48 results on '"Operational strategy"'
Search Results
2. Removal of NH3 and H2S from odor causing tannery emissions using biological filters: Impact of operational strategy on the performance of a pilot-scale bio-filter
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Sameena Begum, Sudharshan Juntupally, Saravanan Palanivel, Gangagni Rao Anupoju, Bharath Gandu, and Vijayalakshmi Arelli
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Environmental Engineering ,Waste management ,Microbial diversity ,Pilot scale ,Full scale ,02 engineering and technology ,General Medicine ,010501 environmental sciences ,021001 nanoscience & nanotechnology ,01 natural sciences ,Odor ,Biofilter ,Environmental science ,0210 nano-technology ,Operational strategy ,0105 earth and related environmental sciences - Abstract
Deodorization of gases emitted from Tanneries using eco-friendly and cost-effective approaches is necessary for the safe disposal of industrial emissions. There is limited research available on the... more...
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- 2021
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3. Optimal operational strategy of hybrid PV/wind renewable energy system using homer: a case study
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Zhang Guiju, Caiyuan Xiao, and Navid Razmjooy
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Renewable Energy, Sustainability and the Environment ,business.industry ,020209 energy ,Photovoltaic system ,02 engineering and technology ,Building and Construction ,Turbine ,Automotive engineering ,Power (physics) ,Renewable energy ,020401 chemical engineering ,Renewable energy system ,Computer data storage ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,Electricity ,0204 chemical engineering ,business ,Operational strategy - Abstract
This study presents an optimal configuration of a hybrid renewable energy source with a wind turbine and a photovoltaic system to fulfil the required electricity power of a medium-size workshop in ... more...
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- 2021
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4. New phase‐changing soft open point and impacts on optimising unbalanced power distribution networks
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Tianrui Li, Eduardo Vega-Fuentes, Chengwei Lou, and Jin Yang
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Mathematical optimization ,Distribution networks ,business.industry ,Computer science ,020209 energy ,020208 electrical & electronic engineering ,Energy Engineering and Power Technology ,02 engineering and technology ,AC power ,Energy storage ,law.invention ,Control and Systems Engineering ,law ,Distributed generation ,Scalability ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,Transformer ,business ,Electrical impedance ,Operational strategy - Abstract
Three-phase unbalanced conditions in distribution networks are conventionally caused by load imbalance, asymmetrical fault conditions of transformers and impedances of three phases. The uneven integration of single-phase distributed generation (DG) worsens the imbalance situation. These unbalanced conditions result in financial losses, inefficient utilisation of assets and security risks to the network infrastructure. In this study, a phase-changing soft open point (PC-SOP) is proposed as a new way of connecting soft open points (SOPs) to balance the power flows among three phases by controlling active power and reactive power. Then an operational strategy based on PC-SOPs is presented for three-phase four-wire unbalanced systems. By optimising the regulation of SOPs, optimal energy storage systems dispatch and DG curtailment, the proposed strategy can reduce power losses and three-phase imbalance. Second-order cone programming (SOCP) relaxation is utilised to convert the original non-convex and non-linear model into an SOCP model which can be solved efficiently by commercial solvers. Case studies are conducted on a modified IEEE 34-node three-phase four-wire system and the IEEE 123-node test feeder to verify the effectiveness, efficiency and scalability of the proposed PC-SOP concept and its operational strategy. more...
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- 2020
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5. Performance analysis of operational strategies for monolithic receiver-reactor arrays in solar thermochemical hydrogen production plants
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Christian Sattler, Andreas Rosenstiel, Anton Lopez-Roman, Stefan Brendelberger, and Cristina Prieto
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thermochemical cycle ,solar fuels ,Energy Engineering and Power Technology ,Flux ,receiver-reactor ,02 engineering and technology ,010402 general chemistry ,Operational optimization ,01 natural sciences ,7. Clean energy ,Array performance ,Limit (music) ,Process engineering ,operational strategy ,Hydrogen production ,Renewable Energy, Sustainability and the Environment ,business.industry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Fuel Technology ,Solar field ,Water splitting ,Environmental science ,Transient (oscillation) ,0210 nano-technology ,business ,snygas - Abstract
Solar thermochemical water splitting was successfully demonstrated with monolithic receiver-reactors in field at 50 kW scale. Since monolithic receiver-reactors are limited in size, several of the reactors will have to be combined in receiver-reactor arrays for large-scale plants. In this study, the yearly performance of solar thermochemical plants for hydrogen production implementing receiver-reactor arrays is investigated. Thereto, a transient receiver-reactor model is used in combination with realistic hourly flux profiles from dedicated MW high temperature solar concentrator systems. The batched operation of receiver-reactors leads to particular requirements of the array. Therefore, an array efficiency is introduced and different control strategies for the solar field are analyzed for performance optimization. Advanced strategies have the potential to substantially (~46%) improve the overall performance compared to the base case. Further design and operational optimization approaches are discussed, which allow approaching the theoretical array performance limit. more...
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- 2020
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6. The impact of emotional energy on the operational strategy of rural tourism enterprises
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Youlin Tang and Qin Yang
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Information Systems and Management ,Coronavirus disease 2019 (COVID-19) ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Energy (esotericism) ,05 social sciences ,Rural tourism ,02 engineering and technology ,Environmental economics ,Computer Science Applications ,0502 economics and business ,0202 electrical engineering, electronic engineering, information engineering ,Stackelberg competition ,Survey data collection ,020201 artificial intelligence & image processing ,Business ,China ,Operational strategy ,050203 business & management - Abstract
Survey data were collected from 179 rural strategic decision-makers in Hunan Province, China. The results show that the emotional energy has a significant long-term impact on rural tourism enterpri... more...
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- 2020
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7. Double-Edged Effect of Temperature on Lithium Dendrites
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Ankit Verma, Feng Hao, Partha P. Mukherjee, and Bairav Sabarish Vishnugopi
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Surface diffusion ,Fundamental study ,Materials science ,Exchange current density ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Energy storage ,0104 chemical sciences ,Dendrite (crystal) ,chemistry ,General Materials Science ,Lithium ,0210 nano-technology ,Operational strategy - Abstract
Lithium metal, although attracting renewed interest for the next revolution in energy storage, continues to be challenged with the detrimental dendrite formation. Recent experimental reports have demonstrated the contrasting impact of thermal attributes on the electrodeposition morphology, showcasing the alleviation and/or aggravation of dendrite formation. Herein, we present a comprehensive discourse to discern the thermally activated physical mechanisms governing lithium electrodeposition morphology. We report that the synergistic effect of enhanced electrolyte transport and surface self-diffusion under a uniform thermal field (∼75 °C) enables adequate dendrite suppression, even at high reaction rates. However, in contrast to this, a localization of the thermal field substantially increases the exchange current density of the confined region, instigating the growth of needle dendrites. Based on our mesoscale analysis, we demarcate safety limits for such an event, beyond which dendrite growth is inevitably triggered. Therefore, though the operational strategy of elevating the cell temperature promises to resolve the challenge of stable electrodeposition, it comes along with the caveat. This fundamental study provides a detailed insight into underlying electrochemical-thermal complexations, critical to the performance and safety of metal-based rechargeable batteries. more...
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- 2020
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8. Increasing the volumetric productivity of fermentative ethanol production using a fed-batch vacuferm process
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Nikolaos Kopsahelis, Anestis Vlysidis, Vasiliki Kachrimanidou, and Ioannis K. Kookos
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Renewable Energy, Sustainability and the Environment ,business.industry ,020209 energy ,Flash evaporation ,Context (language use) ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Scientific method ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,Ethanol fuel ,Process engineering ,business ,Productivity ,Operational strategy ,0105 earth and related environmental sciences - Abstract
This work presents theoretical evidence that the vacuferm technology can confer several advantages even when the fermentor is operated in fed-batch mode with small cycle times aiming to avoid the accumulation of potentially inhibitory side products. More specifically, a mathematical model for a fed-batch fermentor coupled with a vacuum flash tank for in situ ethanol recovery is developed and the simplest possible operational strategy is optimized within the context of maximizing the volumetric productivity of the process. Using numerical values obtained from the literature, it is demonstrated that significant increase in the volumetric productivity of ethanol (up to 33.5 kg EtOH m−3 h−1) can be achieved. Evidently, the results obtained indicate the potential to employ the proposed methodology to operate existing industrial facilities with minor modifications and equipment additions. more...
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- 2020
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9. Review of research on V2X technologies, strategies, and operations
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Hajo Ribberink and Nathaniel S. Pearre
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Architectural engineering ,Service (systems architecture) ,business.product_category ,Renewable Energy, Sustainability and the Environment ,Computer science ,020209 energy ,Context (language use) ,02 engineering and technology ,Grid ,Backup ,Electric vehicle ,0202 electrical engineering, electronic engineering, information engineering ,Energy supply ,business ,Operational strategy ,Reliability (statistics) - Abstract
Vehicle-to-Anything, or V2X, is a term which references technologies that use the energy in the batteries of plug-in electric vehicles (PEVs) for any purpose outside the vehicle. The purpose of this document is to provide a comprehensive and current review of concepts, recently published studies, and demonstration projects/deployments of V2X technology from around the world. While the focus will be kept on recently published studies and current technological developments, some historical perspective and important project reports from earlier periods of V2X development will be included for context. The report is broken down into sections focusing on different classes of V2X service: services to overall regional grid stability and reliability (V2G); reliability and backup energy supply services to individual homes or buildings (V2H); and studies focusing on services to commercial buildings generally inapplicable to residential houses (V2B). Attention will be paid to the operational strategy of the reviewed articles, which reflect a broad spectrum of optimization approaches and objectives. more...
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- 2019
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10. Determination of the intrinsic kinetic parameters of ammonia-oxidizing and nitrite-oxidizing bacteria in granular and flocculent sludge
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Cristopher Da Silva, José Luis Campos, Ángeles Val del Río, Anuska Mosquera-Corral, and Alba Pedrouso
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biology ,chemistry.chemical_element ,Filtration and Separation ,02 engineering and technology ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Kinetic energy ,Oxygen ,Analytical Chemistry ,chemistry.chemical_compound ,Ammonia ,020401 chemical engineering ,chemistry ,Chemical engineering ,Anammox ,Oxidizing agent ,0204 chemical engineering ,Nitrite ,0210 nano-technology ,Operational strategy ,Bacteria - Abstract
The different oxygen affinities of ammonia-oxidizing (AOB) and nitrite-oxidizing bacteria (NOB) are often used to define the operational strategy to achieve partial nitritation (PN) required before the anammox (AMX) process. For this purpose, apparent kinetic parameters are mainly used in the case of granular sludge, which can lead to errors when defining the operational conditions to obtain only nitritation (avoiding nitratation). In the present study, a mathematical methodology is proposed to determine the intrinsic kinetic parameters of AOB and NOB in granular sludge based on data obtained by respirometric assays. Additionally, the oxygen affinity constant (KO2) and maximum specific rate (rmax) of flocculent and granular sludge sample, produced under mainstream and sidestream conditions were determined at various temperatures (15, 20 and 30 °C). The results show that for granules, the intrinsic KO2 and rmax values were lower and higher, respectively, than the apparent values. Furthermore, the KO2 values for flocs and granules at all of the tested temperatures were lower for NOB than for AOB. The values obtained for the kinetic parameters indicated that it is impossible to maintain partial nitritation by only controlling the dissolved oxygen concentration. more...
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- 2019
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11. Operational strategy of customized bus considering customers’ variety seeking behavior and service level
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Jiaguo Liu, Xiaohang Yue, Huida Zhao, and Jian Li
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Economics and Econometrics ,0211 other engineering and technologies ,Social Welfare ,02 engineering and technology ,Management Science and Operations Research ,Industrial and Manufacturing Engineering ,Article ,0502 economics and business ,Operational strategy ,Service (business) ,021103 operations research ,business.industry ,05 social sciences ,Service level ,Environmental economics ,General Business, Management and Accounting ,Customized bus ,Preference ,Work (electrical) ,Public transport ,Variety-seeking behavior ,Construct (philosophy) ,business ,Two-stage model ,050203 business & management - Abstract
In recent years, customized bus (CB) is becoming an innovative model of the public transport system (PTS) in China. This service provides an advanced, timely, personalized, and flexible responses to the demand of the PTS, especially of commuters. Obviously, it could have an impact on public transport (PT) service. For instance, CB services influence the customers' variety-seeking behavior, which results in changes of customer options in different periods. Therefore, customers could be divided into different groups of preference. In this paper, we construct a two-period Hotelling game model by variety-seeking behavior and service level. The results show that, in the first stage, the departure frequency of CB and PT is influenced by variety-seeking behavior and service level. In the second stage, departure frequency is influenced by service level only. Next, although the departure frequency of bus impacts the changes of passenger ratios in different stages, service level appreciably impacts passenger number. From customer surplus and social welfare, we find that adjustment of service level can increase social welfare, which means that CB and PT will reach an optimum effect. The present work can provide a valuable reference to policymakers, practitioners, and others., Highlights • Passengers' changes in different stages were investigated. • The departure frequency, passenger number, and social effects were analyzed. • Operational strategies were proposed. • Interaction between variety-seeking and service investment were studied. more...
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- 2020
12. Differentiation of performance materiality in audit based on business needs
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Vaclovas Lakis, Audrius Masiulevičius, and Vilnius University [Vilnius]
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Technological innovations. Automation ,Entrepreneurship ,Economics, Econometrics and Finance (miscellaneous) ,0211 other engineering and technologies ,audit ,Accounting ,02 engineering and technology ,Audit plan ,Audit ,Management, Monitoring, Policy and Law ,Lietuva (Lithuania) ,Joint audit ,Management of Technology and Innovation ,021105 building & construction ,0502 economics and business ,GE1-350 ,Business and International Management ,Operational strategy ,Materiality (auditing) ,tolerable error ,business.industry ,Corporate governance ,05 social sciences ,HD45-45.2 ,materiality ,risks ,management letter ,[SHS.ECO]Humanities and Social Sciences/Economics and Finance ,Environmental sciences ,Sustainability ,JEL: M - Business Administration and Business Economics • Marketing • Accounting • Personnel Economics/M.M4 - Accounting and Auditing/M.M4.M42 - Auditing ,business ,050203 business & management - Abstract
International audience; Companies are exposed to various risks. Failure to identify and eliminate them may aggravate the development of companies, some of which may be forced to cease operation. Audit can help in revealing the majority of risks. The auditor has an unlimited access to the information, operational strategy, and in some cases even to commercial secrets, of the auditee. Auditor collects a large amount of different information about the company, but it is used only as much as necessary for formulating a conclusion about financial statements. Upon a closer cooperation of the auditor with the persons in charge of the governance of the audited entity, the client needs can be identified and, once the audit plan is slightly revised, the areas that are within the interest of the client can be analysed in more detail. This article aims to investigate the determination of performance materiality in audit to separate classes of transactions based on the principal areas of importance identified by the business undergoing audit. Based on the data collected during the study, a modified model for determining performance materiality in audit was created which can help to identify better the current and potential risks of the distinguished areas. The application of this model enables carrying out an audit in the areas which are of the highest importance to the users of the audit results more effectively and providing them with more detailed information in the management letter. This would help to identify the substantial risks of the auditee in more detail and on time. more...
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- 2018
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13. Methods for optimized design and management of CHP systems for district heating networks (DHN)
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Francesco Bellina and Alessandro Franco
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Exergy ,Computer science ,020209 energy ,Optimum design ,Energy Engineering and Power Technology ,Combined heat and power ,District Heating Network ,Exergy analysis ,Operational strategy ,Renewable Energy, Sustainability and the Environment ,Nuclear Energy and Engineering ,Fuel Technology ,02 engineering and technology ,Intermediate level ,Cogeneration ,020401 chemical engineering ,Robustness (computer science) ,0202 electrical engineering, electronic engineering, information engineering ,Renewable Energy ,0204 chemical engineering ,Design methods ,Sustainability and the Environment ,Industrial engineering ,Incentive ,Efficient energy use - Abstract
The paper analyzes some of the problems connected with the design, construction and management of cogeneration plants for district heating networks (CHP-DHN). Although the advantages of cogeneration systems compared with conventional ones for separate energy production, one of the unresolved problems is that of the variability of operating conditions, can often render the application of these solutions ineffective. In particular, the aim of this study is to propose a multi-objective optimization methodology that tries to take into account both energy and economic aspects. After an analysis of the current scenario, the application and use of CHP plants in the international context and the main technological features, followed by the identification of incentive systems that have allowed or limited the spread, attempts are made to define a design methodology based on a multi-level optimum design based approach for increasing the operation share of CHP. The methodology starts from a general system vision, up to detailed aspects such as the management of a CHP-DHN system, taking into account the multiplicity of variables and constraints involved. This methodology has been applied to two case studies representative of the different applications, to verify its robustness and analyze the possible results obtainable. In particular, a general case was taken into consideration, in which a first level design was performed by analyzing various possible system configurations and evaluating their goodness through the tools provided by the aforementioned multi-objective methodology. Then the methodology has been applied to an intermediate level, taking into consideration an existing CHP-DHN plant and going to evaluate the performance considering possible modification of the operation. The results obtained confirm that a combined energetic and economic approach to design allows to obtain an economically feasible system, but at the same time avoids incurring over-sizing, under-sizing or functioning phenomena far from the concept of energy efficiency, difference of what happens for many plants today in operation. Furthermore, through a simple variation of the modularity of the plant, significant benefits can be obtained. more...
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- 2018
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14. New Procedural Path for F&B Operation and Its Risk Impact on a Nuclear Power Plant
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Wondea Jung
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Risk impact ,Nuclear and High Energy Physics ,010308 nuclear & particles physics ,Computer science ,020209 energy ,02 engineering and technology ,Bleed ,Condensed Matter Physics ,01 natural sciences ,Reliability engineering ,Task (project management) ,law.invention ,Nuclear Energy and Engineering ,law ,0103 physical sciences ,Path (graph theory) ,Nuclear power plant ,0202 electrical engineering, electronic engineering, information engineering ,Operational strategy - Abstract
Although a feed and bleed (F&B) operation is an important emergency task having a significant effect on the risk of a pressurized water reactor–type nuclear power plant, there is a high uncertainty... more...
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- 2018
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15. Optimal conditions for flexible methane production in a demand-based operation of biogas plants
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W. Laperrière, Michel Torrijos, B. Barry, Nicolas Bernet, Jean-Philippe Steyer, B. Pechiné, Laboratoire de Biotechnologie de l'Environnement [Narbonne] (LBE), Institut National de la Recherche Agronomique (INRA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Electricité de France, and Partenaires INRAE more...
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Engineering ,Environmental Engineering ,[SDV]Life Sciences [q-bio] ,020209 energy ,demand-based ,Bioengineering ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,7. Clean energy ,Bioreactors ,Biogas ,biogas ,0202 electrical engineering, electronic engineering, information engineering ,Anaerobic reactor ,Anaerobiosis ,Methane production ,Waste Management and Disposal ,Operational strategy ,0105 earth and related environmental sciences ,Flexibility (engineering) ,Daily production ,Renewable Energy, Sustainability and the Environment ,business.industry ,Environmental engineering ,General Medicine ,overloading ,flexibility ,Base load power plant ,Biofuels ,[SDE]Environmental Sciences ,limits ,business ,Methane ,Intensity (heat transfer) - Abstract
International audience; The aim of the presented work was to study the methane production limits and to determine optimal conditions for flexible operation of an anaerobic reactor in order to set up an operational strategy. Punctual overloads were conducted in a laboratory-scale anaerobic reactor with readily biodegradable solid substrates, and the influences of overload intensity, baseload value and substrate used were investigated. A maximal daily value around 1000 mL/L of reactor for methane production has been assessed. This value did not evolve significantly during experiment time, and conditioned the persistence of overloads as well as the flexibility margin on the reactor, which ranged from +25% to +140% on daily production. Results highlighted the fact that for a maximum flexibility, low organic loading rates are better to work with on this type of reactors. more...
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- 2017
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16. Influence factors and operational strategies for energy efficiency improvement of CNC machining
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Lingling Li, Ying Tang, Congbo Li, and Qian Yi
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0209 industrial biotechnology ,Engineering ,Renewable Energy, Sustainability and the Environment ,Process (engineering) ,business.industry ,Strategy and Management ,05 social sciences ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,02 engineering and technology ,Energy consumption ,Industrial and Manufacturing Engineering ,Manufacturing engineering ,020901 industrial engineering & automation ,Manufacturing ,050501 criminology ,Numerical control ,business ,Operational strategy ,Energy (signal processing) ,0505 law ,General Environmental Science ,Efficient energy use - Abstract
CNC machining is one of the major activities in the manufacturing industry which is responsible for a significant portion of the total consumed energy. However, the energy efficiency of CNC machining is surprisingly low. It is important to provide valuable insights for practitioners to enhance energy efficiency of CNC machining. This paper analyzes the energy consumption characteristics of CNC machining process and exploits the influence factors for energy efficiency improvement through a theoretical analysis. A series of operational strategies for energy efficiency improvement of CNC machining are presented through a review and research framework. The future research directions are identified and summarized for more energy savings. more...
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- 2017
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17. Designing a Fuzzy Expert System with a Hybrid Approach to Select Operational Strategies in Project-Based Organizations with a Selected Competitive Priority
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Alireza Pooya, Ehsan Javanrad, Mohsen Kahani, and Nasser Motahari Farimani
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Engineering ,Fuzzy expert system ,business.industry ,05 social sciences ,0211 other engineering and technologies ,General Social Sciences ,02 engineering and technology ,computer.software_genre ,Hybrid approach ,Expert system ,Engineering management ,Project based ,021105 building & construction ,0502 economics and business ,Systems engineering ,business ,General Economics, Econometrics and Finance ,computer ,Operational strategy ,050203 business & management - Published
- 2017
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18. Customers’ preferences for freight service attributes of China Railway Express
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Qiyuan Peng, Bart Wiegmans, Jingwei Guo, Jafar Rezaei, Yinying Tang, Lori Tavasszy, and Qinglin Li
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Service (business) ,050210 logistics & transportation ,Operations research ,Reliability (computer networking) ,05 social sciences ,0211 other engineering and technologies ,Transportation ,02 engineering and technology ,Management Science and Operations Research ,Investment policy ,Multiple-criteria decision analysis ,Freight demand preferences ,Best-Worst Method (BWM) ,Demand analysis ,Cluster analysis ,Homogeneous ,0502 economics and business ,China Railway Express (CRE) ,021108 energy ,Business ,China ,Operational strategy ,Rail freight services ,Civil and Structural Engineering - Abstract
China Railway Express (CRE) is one of the most important constituent parts of the Belt and Road Initiative. Freight demand analysis is fundamental as a basis for the operational strategy of CRE and the investment policy along the CRE-routes. Most of the existing relevant literature has focused on the organization of the train operations of CRE, with little research related to demand analysis. This paper contributes to filling this gap by estimating customers’ demand preferences for rail freight service attributes, by using a novel multi-criteria decision-analysis (MCDA) method namely Best-Worst Method (BWM). To this end, a BWM survey was conducted in China to capture customers’ preferences for the main attributes that define the transport service offered by CRE. Two variants of BWM, the linear and the Bayesian, are employed for the analysis. Reliability is suggested as the most important attribute for CRE to focus on, to gain customers. We also conduct a cluster analysis based on the results, which helps the CRE operator to identify homogeneous customer segments, and to optimize the use of CRE’s resources with a differentiated pricing strategy. more...
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- 2020
19. Distribution of passenger costs in fixed versus flexible station-based feeder services
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David Leffler, Wilco Burghout, Oded Cats, and Erik Jenelius
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Waiting time ,Service (business) ,050210 logistics & transportation ,Operations research ,business.industry ,Computer science ,05 social sciences ,0211 other engineering and technologies ,Distribution (economics) ,02 engineering and technology ,General Medicine ,demand-responsive feeder ,Traffic dynamics ,simulation ,Fixed service ,Public transport ,021105 building & construction ,0502 economics and business ,automated vehicles ,spatial equity ,business ,Operational strategy ,Transit (satellite) - Abstract
This paper presents a comparative analysis of demand-responsive and fixed-schedule, fixed route operations for a simplified station-based feeder to mass transit scenario. Traffic dynamics, demand-responsive fleet coordination, and the behaviour of individual transit users are represented using a public transit simulation framework. Each operational strategy is simulated for varying levels of demand and two fleet compositions with respect to vehicle capacities and fleet size are compared. The services are evaluated based on resulting passenger waiting times, in-vehicles times and additional waiting time if one is denied boarding a fully occupied vehicle. Results indicate that dividing planned service capacity into larger fleets of smaller vehicles can provide a higher level-of-service to passengers. On an aggregate level, utilizing a fixed operational policy results in shorter and more reliable waiting times for levels of demand where there is slack in service capacity. In scenarios where planned service capacity is sometimes exceeded, the on-demand service provides a more even spatial distribution of passenger waiting times, relative to a fixed service. more...
- Published
- 2020
20. IMPLEMENTING TOTAL PRODUCTIVE MAINTENANCE (TPM) IN MALAYSIAN MANUFACTURING ORGANISATION: AN OPERATIONAL STRATEGY STUDY
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Thurasamy Ramayah, One Yoon Seng, and Muhamad Jantan
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021103 operations research ,Process management ,media_common.quotation_subject ,05 social sciences ,0211 other engineering and technologies ,Developing country ,02 engineering and technology ,Total productive maintenance ,Competitive advantage ,0502 economics and business ,Critical success factor ,Production (economics) ,Operations management ,Quality (business) ,Business ,Inefficiency ,Operational strategy ,050203 business & management ,media_common - Abstract
Total Productive Maintenance (TPM) has been recognized as one of the significant operation strategy to regain the production losses due to equipment inefficiency. Many organizations have implemented TPM to improve their equipment efficiency and to obtain the competitive advantage in the global market in terms of cost and quality. In the implementation of TPM in a manufacturing organization, both Human-oriented and Process-oriented Strategy has been identified as critical success factors. This paper, therefore, focuses on the two TPM operational strategies, which is posited, will improve the extent of TPM implementation in manufacturing organizations. This study is an attempt to look at the TPM implementation from the perspective of a developing country such as MalaysiaKeywords: total productive maintenance, strategy, manufacturing, Malaysia more...
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- 2017
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21. Evaluation of the Standardized Precipitation Index as an early predictor of seasonal vegetation production anomalies in the Sahel
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Anton Vrieling, Dominique Fasbender, Michele Meroni, Felix Rembold, Department of Natural Resources, Faculty of Geo-Information Science and Earth Observation, and UT-I-ITC-FORAGES
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010504 meteorology & atmospheric sciences ,0208 environmental biotechnology ,Growing season ,02 engineering and technology ,Grid cell ,01 natural sciences ,020801 environmental engineering ,ITC-HYBRID ,Linear relationship ,Photosynthetically active radiation ,Climatology ,ITC-ISI-JOURNAL-ARTICLE ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,Electrical and Electronic Engineering ,Precipitation index ,Operational strategy ,METIS-319767 ,0105 earth and related environmental sciences - Abstract
We analysed the performance and timeliness of the Standardized Precipitation Index (SPI) in anticipating deviations from mean seasonal vegetation productivity in the Sahel. Gridded rainfall estimates are used to compute the SPI for 1–6-month timescales, whereas the Z-score of the cumulative value of the Fraction of Absorbed Photosynthetically Active Radiation over the growing season (zCFAPAR) is used as a proxy of seasonal productivity. Results show that the strength of the link varies in space as a function of both the SPI timescale and the timing of the SPI calculation with respect to the vegetative season’s progress. For productivity forecasting, we propose an operational strategy to select per grid cell the SPI timescale and computation time with the highest correlation with zCFAPAR at different moments of the season. The linear relationship between SPI and zCFAPAR is significant for 32–66% of the study area, depending on the timing at which SPI is considered (at 0% and 75% of the seasonal progress, respectively). For these areas, the selected SPI explains on average about 40% of the variance of zCFAPAR and may thus assist in the earlier identification of agricultural drought. more...
- Published
- 2017
22. Complexity and Application of Tobacco Manufacturer Pricing Game considering Market Segments
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Xueli Zhan, Junhai Ma, and Shubing Guo
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0209 industrial biotechnology ,Article Subject ,lcsh:Mathematics ,02 engineering and technology ,lcsh:QA1-939 ,Constructive ,Profit (economics) ,Microeconomics ,symbols.namesake ,020210 optoelectronics & photonics ,020901 industrial engineering & automation ,Market segmentation ,Nash equilibrium ,Modeling and Simulation ,0202 electrical engineering, electronic engineering, information engineering ,Economics ,symbols ,Operational strategy ,Game theory - Abstract
This paper considers price as a strategy using two methods of market segmentation through game theory based on the collected data of several typical cities in Shandong province. Three oligarchs are discussed to analyze the complexity of the market in tobacco system. The effect of different factors on the equilibrium price of Nash equilibrium is discussed. What is more, the variation of parameters drives the system to change to uncertain status, even to bifurcation or chaos. We also discuss the model under normal circumstances, when the three parties jointly take chaos control measures, and its impact on the system. Finally, we clarify chaos control of economic significance. The results indicate that only reasonable pricing strategy is a critical point to achieve maximized profit and maintain orderly operation at the same time, which is a constructive suggestion for tobacco companies’ operational strategy. more...
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- 2017
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23. Optimization model for the design and analysis of an integrated renewable hydrogen supply (IRHS) system: Application to Korea's hydrogen economy
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Jiyong Kim and Minsoo Kim
- Subjects
Renewable Energy, Sustainability and the Environment ,business.industry ,Computer science ,020209 energy ,05 social sciences ,Energy Engineering and Power Technology ,Hydrogen technologies ,02 engineering and technology ,Condensed Matter Physics ,Renewable energy ,Hydrogen supply ,Fuel Technology ,Hydrogen economy ,0502 economics and business ,Economic evaluation ,0202 electrical engineering, electronic engineering, information engineering ,Production (economics) ,050207 economics ,business ,Process engineering ,Integer programming ,Operational strategy - Abstract
This paper presents a framework for the design and assessment of a renewable energy sources (RES)-based hydrogen supply system. We generate an integrated renewable hydrogen supply (IRHS) system that includes various types of RES and hydrogen technologies such as production, storage, and transportation. We then develop a multi-period deterministic optimization model for the IRHS system by using a mixed integer linear programming (MILP) technique. The proposed model optimizes the configuration and operational strategy of the IRHS system. The capability of the proposed model is demonstrated through its application to the design problem of Korea's future hydrogen economy. We perform an economic evaluation to identify the major parameters for the required cost of the energy system infrastructure. more...
- Published
- 2016
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- View/download PDF
24. A systems approach to developing a new metro for megalopoleis
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Clive J. Roberts, Felix Schmid, and Marcelo Blumenfeld
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050210 logistics & transportation ,Engineering ,Transportation planning ,business.industry ,Process (engineering) ,05 social sciences ,0211 other engineering and technologies ,021107 urban & regional planning ,Transportation ,02 engineering and technology ,Transport engineering ,0502 economics and business ,Line (text file) ,business ,Operational strategy ,Civil and Structural Engineering - Abstract
The significant growth in the size of cities has led to an increase in distances travelled that emphasises the systemic shortcomings of metros. Metro systems are hindered by a paradox between the time to access stations and the average speed on the line, which prevents them from offering competitive door-to-door speeds within the natural time budgets of users. The authors present a novel methodology that combines the back-casting method with a systems engineering approach to develop a robust problem-solving process that can cope with the uncertainty of future scenarios. The approach has been used to develop a solution to the paradox, that is based on an operational strategy where autonomous vehicles stop in different patterns at stations along a line. It is proposed that vehicles will travel in platoons and be controlled by vehicle-to-vehicle communication algorithms similarly to those in automated highways. Simulations show that this strategy can increase the average speed on a line by 129%, reducing door-to-door journey times by up to 45%, compared to conventional operations. Moreover, capacity is increased by 30% within conventional platform lengths. In conclusion, this process can lead to solutions that accommodate future demands and change current trends into more desirable futures. more...
- Published
- 2016
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25. Synthesis of tri-generation systems: Technology selection, sizing and redundancy allocation based on operational strategy
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Viknesh Andiappan and Denny K. S. Ng
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Engineering ,Energy demand ,Electrical load ,business.industry ,020209 energy ,General Chemical Engineering ,Real-time computing ,02 engineering and technology ,Thermal load ,Sizing ,Computer Science Applications ,Reliability engineering ,020401 chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,Redundancy (engineering) ,Overall performance ,0204 chemical engineering ,business ,Operational strategy - Abstract
Tri-generation system is a facility which produces heat, power and cooling simultaneously from a single fuel source. In the industry, such system is commonly operated via two strategies; Following Electrical Load (FEL) or Following Thermal Load (FTL). However, these operating strategies may lead to huge amount of energy that is wasted. In this respect, several works have proposed a switching strategy, whereby tri-generation systems would interchange between FEL and FTL modes depending on energy demand. Unfortunately, the design of tri-generation based on this strategy has received limited attention. Besides, tri-generation operations often face challenges in equipment reliability. As tri-generation systems contain a network of interconnected equipment, equipment failures would disrupt the overall performance of a tri-generation system. As such, this work proposes a novel systematic optimisation approach to design a robust tri-generation system which can operate optimally in its operating strategies. In addition, the proposed approach can simultaneously determine type, size and required equipment redundancy (e.g. operating and standby units) of technologies while considering operating strategies in a tri-generation system. A palm biomass-based tri-generation system (BTS) case study is solved to illustrate the proposed approach. more...
- Published
- 2016
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26. A hierarchical pricing decision process on a dual-channel problem with one manufacturer and one retailer
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Qing Ding, Zhicong Pan, and Ciwei Dong
- Subjects
TheoryofComputation_MISCELLANEOUS ,Economics and Econometrics ,Pricing decision ,021103 operations research ,Operations research ,Computer science ,Process (engineering) ,05 social sciences ,Single type ,0211 other engineering and technologies ,02 engineering and technology ,Management Science and Operations Research ,General Business, Management and Accounting ,Industrial and Manufacturing Engineering ,Dual (category theory) ,Product (business) ,0502 economics and business ,Stackelberg competition ,Marketing ,Operational strategy ,050203 business & management ,Communication channel - Abstract
In this paper, we consider a dual-channel problem with one manufacturer and one retailer. The manufacturer, acting as the Stackelberg leader, sells a single type of product through a traditional channel to the retailer and/or through a direct channel to customers. The retailer, acting as the follower, orders the products from the manufacturer and sells to the customers. We consider a hierarchical pricing decision process and find the joint optimal strategy for three prices: the wholesale price, the retail price in the traditional channel, and the selling price in the direct channel. Our framework involves various operational strategies, e.g., dual channels, a single traditional channel, a single direct channel, equal-pricing strategy in which the wholesale price is equal to the selling price in the direct channel, price-matching strategy in which the product is priced the same on the website and the retail store, etc. We provide criteria to identify different operational strategies, and compare the performance of the strategies. Our results show that operating dual channels is optimal for the manufacturer only under some conditions, and equal-pricing strategy and price-matching strategy may not always be optimal for the manufacturer. Our results supplement the findings for dual-channel problem in the literature in a comprehensive model framework. more...
- Published
- 2016
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27. Architecture for demand responsive HVAC in a commercial building for transformer lifetime improvement
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Pradeep Kumar Yemula and Charan Teja S
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business.industry ,020209 energy ,Field data ,020208 electrical & electronic engineering ,Energy Engineering and Power Technology ,02 engineering and technology ,Distribution transformer ,Automotive engineering ,law.invention ,Demand response ,Water chiller ,law ,HVAC ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,Electrical and Electronic Engineering ,Architecture ,Transformer ,business ,Operational strategy - Abstract
Overloading and ageing effects contribute to 12-15% of distribution transformer failures in India. This research is motivated in extending life of transformer by using demand response as an operational strategy where the demand response events are issued by predicting overheating of transformer before it occurs. In this paper heating ventilation and air conditioning is considered as a flexible load for responding to demand response events. A demo site is created at 11 KV/440 V substation with 1.6 MVA transformer at Indian Institute of Technology Hyderabad (IITH) campus and the proposed architecture and algorithm is implemented. This substation supplies power to chiller plant and three academic buildings with heating ventilation and air conditioning (HVAC). Analysis for improving the transformer lifetime is carried out for 5 consecutive days during the period (25–29)th Feb 2020 using real time field data. It is observed that during this period 11 demand response events occurred with a total demand response of 919 kWH. From the obtained results it is observed that there is a saving of 15 hoursof transformer life within a period of 5 days (120 hours) of transformer operation. The key contribution in this paper is to bring together three concepts transformer lifetime estimation, HVAC flexibility and demand response for improving the transformer lifetime. more...
- Published
- 2020
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28. A novel method and operation strategy for the improved performance of an absorption heat transformer
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Yang Jing, Liu Feng, Taixiu Liu, and Jun Sui
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Materials science ,020209 energy ,media_common.quotation_subject ,Energy Engineering and Power Technology ,02 engineering and technology ,Coefficient of performance ,Inertia ,Instability ,Industrial and Manufacturing Engineering ,Automotive engineering ,Waste heat recovery unit ,law.invention ,Improved performance ,Heat consumption ,020401 chemical engineering ,law ,0202 electrical engineering, electronic engineering, information engineering ,0204 chemical engineering ,Transformer ,Operational strategy ,media_common - Abstract
Recently, waste heat recovery in industry applications of absorption heat transformers has developed rapidly. Due to the instability of the heat source and constantly changing heat load, it is difficult to adjust and control an absorption heat transformer to meet the needs of heat supply and heat consumption. Thus, the dynamic performance caused by thermal inertia and solution concentration inertia becomes increasingly important. A dynamic model of a vertical falling-film absorption heat transformer using LiBr/H2O as the working pair is established in this paper and validated by experimental data. The simulation results show that there is a contradiction at different stages of equipment operation. Less solution reserved in the system is more advantageous during start-up and load changing, but reserving less solution is opposite under internal and external fluctuations. Thus, a system improvement method and operational strategy are proposed to resolve this contradiction. The improved system has a faster temperature stabilization speed and higher total Coefficient of performance (COP) under start-up, load changing, and operating condition fluctuations. The stabilization time for start-up and load changing processes can be reduced by 43.8%, and a 20 kW absorption heat transformer can save about 212.2 kJ for each load changing operation. more...
- Published
- 2020
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29. Forecasting electricity consumption based on machine learning to improve performance: A case study for the organization of petroleum exporting countries (OPEC)
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Hanan Aljuaid, Abdullah Khan, Asfandyar Khan, Muhammad Asim, Mukhtar Fatihu Hamza, Haruna Chiroma, Javed Iqbal Bangash, and Muhammad Imran
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Consumption (economics) ,General Computer Science ,business.industry ,020206 networking & telecommunications ,02 engineering and technology ,Machine learning ,computer.software_genre ,Energy conservation ,Improved performance ,chemistry.chemical_compound ,chemistry ,Control and Systems Engineering ,Order (exchange) ,0202 electrical engineering, electronic engineering, information engineering ,Economics ,Petroleum ,020201 artificial intelligence & image processing ,Artificial intelligence ,Electricity ,Electrical and Electronic Engineering ,business ,Cuckoo search ,computer ,Operational strategy - Abstract
Forecasting electricity consumption can help policymakers to properly plan for economic development. This is possible through energy conservation by avoiding excessive consumption of electricity through enhanced operational strategy. Power utilization and financial improvement are in long term relationship with all member nations of the Organization of Petroleum Exporting Countries (OPEC). In order to improve electricity consumption forecasting performance, this paper proposes an alternate machine learning method for forecasting OPEC electricity consumption with improved performance. The modeling of the OPEC electricity utilization forecast depends on the Cuckoo Search Algorithm by means of Levy flights. The proposed method is found to be efficient, operative, consistent, and robust compared to the electricity consumption forecasting methods that have already been discussed by researchers in the literature. In turn, energy conservation can be motivated in the twelve OPEC member countries. more...
- Published
- 2020
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- View/download PDF
30. Optimal operational strategy for an offgrid hybrid hydrogen/electricity refueling station powered by solar photovoltaics
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Xu, Xiao, Hu, Weihao, Cao, Di, Huang, Qi, Liu, Wen, Jacobson, Mark Z., Chen, Zhe, Sustainable Energy Supply Systems, Energy and Resources, Sustainable Energy Supply Systems, and Energy and Resources
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Battery (electricity) ,Hydrogen ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Automotive engineering ,Photovoltaics ,Hybrid hydrogen/electricity refueling station ,Renewable Energy ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Operational strategy ,Sustainability and the Environment ,Mixed-integer linear programming ,Renewable Energy, Sustainability and the Environment ,business.industry ,021001 nanoscience & nanotechnology ,Hydrogen vehicle ,Electrical grid ,0104 chemical sciences ,Expected shortfall ,Hydrogen-fueled vehicles ,Electrical vehicles ,Solar photovoltaics ,chemistry ,Environmental science ,Electricity ,0210 nano-technology ,business ,Conditional value-at-risk - Abstract
This study introduces a novel concept to provide both electric charging and hydrogen refueling at the same location. A hybrid hydrogen/electricity refueling station (HERS) powered only by solar photovoltaics in a remote area without access to the electrical grid is proposed. This station provides electricity for battery electric vehicles (BEVs) and simultaneously produces hydrogen for hydrogen fuel cell vehicles (HFCVs). Owing to the variability of PV power output and electricity price, electricity and hydrogen demands, this study investigates a possible operational strategy for the offgrid HERS. The objective is to propose optimal operational strategies for such a station to maximize profits by selling electricity and hydrogen to owners of both BEVs and HFCVs. Failure to supply electricity and hydrogen is treated as a penalty in the target function. The scenario-based stochastic method is adopted for this uncertainty modeling, and the conditional value-at-risk is also considered for evaluating the financial risks. The results reveal that 1) the proposed HERS can simultaneously supply the demands of the BEVs and HFCVs and 2) the behavior of HERS (providing energy to BEVs or HFCVs) is determined by several major factors, namely, electricity and hydrogen prices, and the penalty coefficients. more...
- Published
- 2020
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31. Optimal Strategy for ATC Enhancement and Assessment in presence of FACTS devices and Renewable Generation
- Author
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Devesh Shukla, Satyendra Singh, and Soumya R. Mohanty
- Subjects
business.industry ,Computer science ,020209 energy ,Emphasis (telecommunications) ,02 engineering and technology ,Reliability engineering ,Renewable energy ,Electric power system ,Electricity generation ,Distributed generation ,0202 electrical engineering, electronic engineering, information engineering ,Renewable generation ,business ,Operational strategy - Abstract
Available Transfer Capability is determinental in facilitating operation of power system economically, reliably and securely. Advancements in the power generation techniques and shift in generation methodologies from centralized to disbursed/distributed generation with increased emphasis on renewable sources has complicated the assessment and enhancement of ATC. In this paper a multi-stage operational strategy for enhancement and assessment of ATC in the presence of renewable sources of generation and FACTS devices is presented. The developed method is implemented on Modified IEEE 24 bus test system. more...
- Published
- 2018
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32. Operational Strategy of Energy Storage to Address Day-Ahead Scheduling Errors in High RE Scenario
- Author
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Anjali Jain, Partha Das, Yamujala Sumanth, Priyanka Kushwaha, Rohit Bhakar, and Jyotirmay Mathur
- Subjects
Job shop scheduling ,Computer science ,020209 energy ,Load modeling ,0202 electrical engineering, electronic engineering, information engineering ,Generating unit ,Renewable generation ,02 engineering and technology ,Operational strategy ,Energy storage ,Reliability engineering ,Scheduling (computing) - Abstract
High penetration of intermittent renewable generation may impose supply-demand mismatch in real time operation due to day-ahead forecast errors. This results in increase of cycling from conventional generating unit fleet there by cost of generation increases. To address the issue, this paper presents a MILP based 2- step security constrained scheduling problem considering Day-ahead hourly scheduling and intra hour re-dispatch. Further, benefits of using Energy Storage Systems for balancing and reserve services are evaluated. Effectiveness of proposed model is studied on IEEE-118 test system. more...
- Published
- 2018
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33. Optimal strategy between extraction and storage of crude oil
- Author
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Farid Mkaouar, Ilyes Abid, Khaled Guesmi, Stéphane Goutte, Laboratoire d'Economie Dionysien (LED), Université Paris 8 Vincennes-Saint-Denis (UP8), IPAG Lab (IPAG Lab), Ipag, Institut de Systématique, Evolution, Biodiversité (ISYEB ), Muséum national d'Histoire naturelle (MNHN)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), IPAG Paris, Laboratoire de Probabilités et Modèles Aléatoires (LPMA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Pierre et Marie Curie - Paris 6 (UPMC), IPAG Business School, Goutte, Stéphane, and Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS) more...
- Subjects
[MATH.MATH-PR] Mathematics [math]/Probability [math.PR] ,Spot contract ,[QFIN.PR]Quantitative Finance [q-fin]/Pricing of Securities [q-fin.PR] ,0211 other engineering and technologies ,General Decision Sciences ,02 engineering and technology ,Agricultural engineering ,Management Science and Operations Research ,[QFIN.CP]Quantitative Finance [q-fin]/Computational Finance [q-fin.CP] ,[SHS]Humanities and Social Sciences ,[MATH.MATH-ST]Mathematics [math]/Statistics [math.ST] ,[MATH]Mathematics [math] ,[SHS.ECO] Humanities and Social Sciences/Economics and Finance ,Oil storage ,Operational strategy ,Stock (geology) ,ComputingMilieux_MISCELLANEOUS ,Mathematics ,[STAT.AP]Statistics [stat]/Applications [stat.AP] ,021103 operations research ,[QFIN]Quantitative Finance [q-fin] ,[MATH.MATH-OC] Mathematics [math]/Optimization and Control [math.OC] ,Crude oil ,[QFIN.ST]Quantitative Finance [q-fin]/Statistical Finance [q-fin.ST] ,[SHS.ECO]Humanities and Social Sciences/Economics and Finance ,[QFIN] Quantitative Finance [q-fin] ,[MATH.MATH-PR]Mathematics [math]/Probability [math.PR] ,[MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC] - Abstract
This paper deals with the optimal choice between extraction and storage of crude oil over time. An oil producer should decide on the proportion of oil extracted to sell and the proportion to store. This optimal operational strategy should be conducted on a daily basis while taking into consideration physical, operational and financial constraints such as: storage capacity, crude oil spot price, total quantity available for possible extraction or the maximum amount which could be invested at time t for the extraction choice. Our main results show that when the stock is close to be full, it is better to sell a higher part of the extracted quantity. Therefore, if the stock is empty, the best strategy is to secure the reserves against oil prices fluctuations. In the case of full stock, it is useless to put more quantity in reserves and the best strategy is to sell more output. But, if the stock and the available reserves for extraction are half full, the optimal strategy is to consider both selling and storing output. more...
- Published
- 2018
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34. Combined operation of outlet streams swing with partial-feed in a simulated moving bed
- Author
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Ji Yeon Song, Kyung Min Kim, and Chang Ha Lee
- Subjects
Pressure drop ,Chromatography ,business.industry ,General Chemical Engineering ,010401 analytical chemistry ,02 engineering and technology ,General Chemistry ,Operating variables ,Raffinate ,STREAMS ,Swing ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Environmental science ,Node (circuits) ,Simulated moving bed ,0210 nano-technology ,Process engineering ,business ,Operational strategy - Abstract
The operational strategy of outlet streams swing (OSS) operation combined with partial-feed (PF) operation, OSS-PF, was studied under the constraint of maximum allowable pressure and flow-rate. Its separation performance and dynamic behavior were compared with those of OSS operation and conventional simulated moving bed (SMB) chromatography. During OSS-PF operation, the switching period consisted of two steps; raffinate was produced during the closed condition of extract node and feed node in the first step, while extracts were produced and feeds were injected during the closed condition of raffinate node in the second step. As a result, OSS-PF operation could be performed under the allowable maximum flow-rate in the corresponding conventional SMB without generating an additional pressure drop at the adsorbent bed, which was different from OSS operation. OSS-PF operation successfully improved the separation performance of the conventional SMB with regard to extract purity, raffinate recovery and raffinate productivity with equivalent eluent consumption. The step ratio during a switching period worked as one of important operating variables in separation performance. The dynamic behavior of OSS-PF operation was analyzed and compared with that of OSS and conventional SMB using simulated concentration profiles in the fluid phase. more...
- Published
- 2016
- Full Text
- View/download PDF
35. Optimization Design of Capacity and Operation Strategy for Building Level Distributed Energy System
- Author
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Naiping Gao, Tong Zhu, Zhu Wu, and Tao Zhang
- Subjects
Exergy ,Engineering ,business.industry ,020209 energy ,Energy balance ,Mechanical engineering ,non-liner programming (NLP) ,02 engineering and technology ,General Medicine ,Energy consumption ,Energy conservation ,Internal combustion engine ,Distributed generation ,Heat recovery ventilation ,0202 electrical engineering, electronic engineering, information engineering ,Distributed energy system(DES) ,Process engineering ,business ,operational strategy ,Engineering(all) ,Optimization design ,Efficient energy use - Abstract
Combined cooling, heating, and power (CCHP) system is an effective solution to implement energy-step-utilization, and achieve energy conservation and emissions reduction. In this paper, the energy requirements are obtained by energy consumption simulation on a building and are classified to several subcategories by energy grade of exergy. The CCHP systems include natural gas internal combustion engine, heat recovery system, gas boiler, absorption chiller, and heat exchangers. The economic efficiency, energy efficiency, and environmental benefits are taken in account to establish a multi-objective evaluation methodology. According the energy balance principle, an integrated optimization model of CCHP system is established by the means of non-liner programming (NLP). The optimization model will automatic match the energy demands’ grade and the result will show the capacity of all the equipment and the operation strategy in the whole year. The computational results also prove the integrated optimization method is valid. more...
- Published
- 2016
- Full Text
- View/download PDF
36. Investigating the Optimum Operational Strategy of Energy Storage Tank by Using Particle Swarm Algorithm
- Author
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Hassan Hajabdollahi and Najmeh Pourgholamali
- Subjects
Fluid Flow and Transfer Processes ,Chiller ,Optimal design ,020209 energy ,Particle swarm optimization ,02 engineering and technology ,Condensed Matter Physics ,Energy storage ,law.invention ,Particle swarm algorithm ,Control theory ,law ,Genetic algorithm ,0202 electrical engineering, electronic engineering, information engineering ,Absorption refrigerator ,Operational strategy ,Mathematics - Abstract
Optimal design of an energy storage tank system is presented in this study. Total annual cost is considered as the objective. To minimize the total annual cost, 24 design parameters including the operational strategy of the chiller in each hour during a sample day are selected. A Particle Swarm Optimization (PSO) algorithm is used for three different strategies including partial storage (PS), full storage (FS), and variable storage (VS), separately. In addition, this procedure is performed for both electrical and absorption chillers. There was a 25.21% and 13.80% improvement in total annual cost observed in the VS strategy compared with the PS and FS strategies, respectively, in the case of an electrical chiller. Furthermore, 23.47% and 8.01% improvement in total annual cost is observed in the VS strategy compared with the PS and FS strategies, respectively, in the case of an absorption chiller. Moreover, the electrical chiller was found to be more suitable in this study but no sensible difference is observed in the FS strategy. Finally the optimum results of the PSO algorithm is compared with the Genetic Algorithm (GA) and differences are reported. more...
- Published
- 2015
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- View/download PDF
37. Estimation and optimization operation in dealing with inflow and infiltration of a hybrid sewerage system in limited infrastructure facility data
- Author
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Mingkai Zhang, Hanchang Shi, Yanchen Liu, and He Jing
- Subjects
Engineering ,business.industry ,0208 environmental biotechnology ,Environmental engineering ,02 engineering and technology ,Inflow ,010501 environmental sciences ,Assessment index ,01 natural sciences ,020801 environmental engineering ,Infiltration (hydrology) ,Wastewater ,Sewerage ,Sewage treatment ,business ,Effluent ,Operational strategy ,0105 earth and related environmental sciences ,General Environmental Science - Abstract
Inflow and infiltration (I/I) are serious problems in hybrid sewerage systems. Limited sewerage information impedes the estimation accuracy of I/I for each catchment. A new method dealing with I/I of a large-scale hybrid sewerage system with limited infrastructure facility data is proposed in this study. The catchment of representative pump stations was adopted to demonstrate the homological catchments that have similar wastewater fluctuation characteristics. Homological catchments were clustered using the self-organizing map (SOM) analysis based on long-term daily flow records of 50 pumping stations. An assessment index was applied to describe the I/I and overflow risk in the catchment based on the hourly wastewater quality and quantity data of representative pump stations. The potential operational strategy of homological catchments was determined by the assessment index of representative pump stations. The simulation results of the potential operational strategy indicated that the optimized operation strategy could reduce surcharge events and significantly improve the quality of wastewater treatment plant effluent. more...
- Published
- 2017
- Full Text
- View/download PDF
38. Optimum sizing and operational strategy of CHP plant for district heating based on the use of composite indicators
- Author
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Michele Versace and Alessandro Franco
- Subjects
Exergy ,Optimization ,Engineering ,020209 energy ,Composite number ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,02 engineering and technology ,Industrial and Manufacturing Engineering ,Combined heat and power ,020401 chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,0204 chemical engineering ,Electrical and Electronic Engineering ,Process engineering ,Operational strategy ,Civil and Structural Engineering ,Waste management ,business.industry ,Mechanical Engineering ,Composite indicators ,Building and Construction ,Composite indicator ,Pollution ,Sizing ,Power (physics) ,Exergy analysis ,General Energy ,Heating system ,Energy (all) ,District heating systems ,Quasi-steady model ,business ,Thermal energy - Abstract
The aim of the paper is to discuss the possible use of Combined Heat and Power (CHP) plants and to highlight some abnormal effects, generated by the available support mechanisms, both in sizing and management and to propose guidelines for defining optimal operational strategies of CHP power plants. Some composite indicators are proposed to give a more comprehensive assessment of the performances of a plant, for the design and optimization phase and for a possible approach to support mechanisms. A new composite indicator is introduced in order to assess the benefits of different scenarios. The method is tested with reference to a case study: a medium size district heating system, powered by a CHP plant supported by conventional auxiliary boilers. Data coming from a real plant equipped with a remote monitoring system are analyzed. Operating data of a typical month are used in order to test the approach for the reference system. The paper shows how the use of the defined composite indicators can modify in a meaningful way the operating strategy of the CHP, increasing a lot the share of thermal energy produced with the CHP unit with respect to the conventional boilers. more...
- Published
- 2017
39. A comprehensive survey on microgrippers design: operational strategy
- Author
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Nicola Pio Belfiore, Matteo Verotti, Alden Dochshanov, Dochshanov, Alden, Verotti, Matteo, and Belfiore, Nicola P.
- Subjects
0209 industrial biotechnology ,Engineering ,Control algorithm ,microgrippers ,business.industry ,Mechanical Engineering ,MEMS ,silicon ,actuation ,microactuation ,Computer Science Applications1707 Computer Vision and Pattern Recognition ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Computer Graphics and Computer-Aided Design ,Manufacturing engineering ,Computer Science Applications ,Computer Science::Robotics ,Engineering management ,020901 industrial engineering & automation ,Mechanics of Materials ,Mechanics of Material ,0210 nano-technology ,business ,Operational strategy - Abstract
This article provides an overview of the operational strategies adopted in microgrippers design. The review covers microgrippers recently proposed in Literature, some of which have been systematically presented in a companion paper, where their topological, kinematic, and structural characteristics are discussed. In the present contribution, the prevalent actuation methods and the operational aspects are discussed: the tip displacement, the tip force, the actuation voltage, and the amplification factor are the reference parameters that are adopted to compare the different types of actuation and operational strategies. In addition, the control strategies and control algorithms currently adopted are reviewed. more...
- Published
- 2017
40. Operational strategy, economic and environmental performance of sludge treatment reed bed systems - based on 28 years of experience
- Author
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Steen Lykke Nielsen and Julie Dam Larsen
- Subjects
Engineering ,Environmental Engineering ,Denmark ,0208 environmental biotechnology ,02 engineering and technology ,010501 environmental sciences ,Reed bed ,Poaceae ,01 natural sciences ,Waste Disposal, Fluid ,Hazardous waste ,Capital cost ,Operating expense ,Operational strategy ,0105 earth and related environmental sciences ,Water Science and Technology ,Waste management ,Sewage ,business.industry ,Environmental engineering ,Dewatering ,020801 environmental engineering ,Europe ,Biodegradation, Environmental ,Sludge dewatering ,Sewage sludge treatment ,business ,Water Pollutants, Chemical - Abstract
Sludge treatment reed bed (STRB) systems have been used for dewatering and mineralisation of sludge in Europe since 1988. STRB systems provide substantial environmental, economic, and operational benefits compared to mechanical sludge dewatering solutions such as belt presses and centrifuges. They require less energy, no chemicals, reduce the sludge volume and produce bio solids with dry solid contents up to 20–40% under Danish climate conditions, depending on the sludge quality. Experience has shown that sludge treated in STRBs represents a high quality product with a low content of pathogens and hazardous organic compounds, qualities that make it suitable for recycling on agricultural land. The upfront capital cost for STRBs are often higher compared to mechanical dewatering devices. However, the operational expenses (OPEX) (including energy, chemicals, bio solid handling) are significantly lower compared to conventional mechanical dewatering devices, delivering an economic break-even of about 3–5 years. This paper provides an overview of the operation and maintenance costs and environmental benefits of a typical STRB based on the experiences gained from the operation of a large number of STRBs with yearly treatment capacities between 100 and 3,000 tonnes of dry solid up to approximately 250,000 PE in Denmark and Europe. more...
- Published
- 2016
41. Grid voltage level spanning operational strategies for battery energy storage systems in distribution grids
- Author
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Joachim Przibylla, Lorenz Viernstein, and Rolf Witzmann
- Subjects
Engineering ,Grid voltage ,business.industry ,020209 energy ,Electrical engineering ,02 engineering and technology ,Business model ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Grid ,Battery energy storage system ,Reliability engineering ,law.invention ,Hardware_GENERAL ,law ,0202 electrical engineering, electronic engineering, information engineering ,Renewable generation ,Battery storage ,business ,Transformer ,Operational strategy - Abstract
With rising renewable generation and battery storage prices decreasing, storage integration in electrical grids is increasingly discussed as an option to avoid conventional grid extension as well as an option for new business models for utilities and customers. While the majority of available literature focuses only on the low-voltage level, the impact that distributed storages can have on the superimposed medium-voltage grid has to be considered. Especially in grids with high distributed renewable generation, battery storages can contribute to a grid operation conforming to standards. In this paper an operational strategy is presented that includes medium-voltage/low-voltage transformers as well as the high-voltage/medium-voltage transformer into the control algorithm. Results obtained by simulations show, that battery storage systems in low-voltage grids can efficiently relieve the superimposed medium-voltage grid and the transformer connecting it to the high-voltage level. more...
- Published
- 2016
- Full Text
- View/download PDF
42. Seasonal predictability of water resources in a Mediterranean freshwater reservoir and assessment of its utility for end-users
- Author
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Marco Turco, Pere Quintana-Seguí, Raül Marcos, and Ma Carmen Llasat
- Subjects
Mediterranean climate ,Environmental Engineering ,010504 meteorology & atmospheric sciences ,Meteorology ,End user ,0208 environmental biotechnology ,02 engineering and technology ,01 natural sciences ,Pollution ,020801 environmental engineering ,Water resources ,Variable (computer science) ,Climatology ,Linear regression ,Environmental Chemistry ,Environmental science ,Predictability ,System 4 ,Waste Management and Disposal ,Operational strategy ,0105 earth and related environmental sciences - Abstract
In this study we explore the seasonal predictability of water resources in a Mediterranean environment (the Boadella reservoir, in north-eastern Spain). Its utility for end-users is assessed through the analysis of economic value curve areas (EVA). Firstly, we have built monthly multiple linear regression (MLR) models for the in-flow, out-flow and volume anomalies by identifying the underlying relationships between these predictands and their potential predictors, both meteorological and human influenced: rainfall, maximum and minimum temperatures, reservoir volume and discharge. Subsequently, we have forecast the monthly anomalies with these models for the period 1981-2010 (up to seven months ahead). We have tested the aforementioned models with four strategies in a leave-one-out cross-validation procedure (LOOCV): a) Climatology (Clim.), b) persistence (Pers.), c) antecedent observations+climatology (A+Clim.), d) antecedent observations+European Centre for Medium-range Weather Forecasts (ECMWF) System 4 anomalies (A+S4). Climatology is the operational strategy against which the other approximations are compared. The second and third approaches only use observations as input data. Finally, the last one combines both observations and ECMWF System 4 forecasts. The LOOCV revealed that reservoir volume is the variable best described by the MLR models, followed by in-flow and out-flow anomalies. In the case of volume anomalies, the predictability displayed provides added value with respect to climatology with a minimum of four months in advance. For in-flow and out-flow this is true at one month ahead, and regarding the latter variable we encounter enhanced predictability also at longer horizons for the summer months, when water demands peak (a valuable result for end-users). Hence, there is a window of opportunity to develop future operational frameworks that could outperform the use of climatology for these variables and forecast horizons. more...
- Published
- 2016
43. Optimal management of an oil exploitation
- Author
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Thomas Lim, Idris Kharroubi, and Stéphane Goutte
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Mathematical optimization ,Profit (accounting) ,Optimization problem ,021103 operations research ,Spot contract ,Renewable Energy, Sustainability and the Environment ,Computer science ,0211 other engineering and technologies ,Energy Engineering and Power Technology ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,02 engineering and technology ,Crude oil ,Maturity (finance) ,Optimal management ,Profit (economics) ,Nuclear Energy and Engineering ,Volatility (finance) ,Oil field ,Robustness (economics) ,Oil storage ,Operational strategy - Abstract
The aim of this paper is to deal with the optimal choice between extraction and storage of crude oil during time under a large panel of constraints for a fixed maturity T. We consider a manager that owns an oil field from which he can extract oil and decide to sell or to store it. This operational strategy has to be done in continuous time and has to satisfy physical, operational and financial constraints such as: storage capacity, crude oil spot price volatility, amount quantity available for possible extraction or the maximum amount which could be invested at time t for the extraction choice. We solve the optimization problem of the manager’s profit under this large panel of constraints and provide an optimal strategy. We then deal with different numerical scenario cases to check the robustness and the corresponding optimal strategies given by our model. more...
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- 2018
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44. Operational Strategy, R&D and Intra-metropolitan Clustering in a Polycentric Structure: The Advanced Electronics Industries of the Los Angeles Basin
- Author
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Luis Suarez-Villa and Wallace Walrod
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Structure (mathematical logic) ,Engineering ,business.industry ,05 social sciences ,0211 other engineering and technologies ,0507 social and economic geography ,021107 urban & regional planning ,02 engineering and technology ,Environmental Science (miscellaneous) ,Structural basin ,Metropolitan area ,Civil engineering ,Urban Studies ,Regional science ,Electronics ,Cluster analysis ,business ,050703 geography ,Operational strategy - Abstract
The multiple clustering of economic activities is one of the most distinctive characteristics of a polycentric metropolitan area. The relationship between intra-metropolitan location, research and development (R&D), operational strategy and production is analysed, to determine whether spatial clusters are more supportive of R&D than non-clustered locations. Two major operational strategies commonly utilised in advanced electronics production, outsourcing and the use of just-in-time (JIT) production methods, and their relationship with intra-metropolitan location and R&D intensity are considered, to determine their effects on spatially clustered and non-clustered establishments. The intra-metropolitan distribution of clusters in the Los Angeles basin, their potential industrial district effects, and the role of externalities are also evaluated, to determine the relationship between polycentricity and high-technology production. Extensive statistical analyses are then undertaken with establishment-level data for seven 4-digit advanced electronics sectors, in the telecommunications, electromedical and advanced computer equipment manufacturing groups in the Los Angeles basin. Comparative statistical analyses on a sample of Silicon Valley establishments are also performed, in order to place the Los Angeles basin's findings in perspective. The results of this research contradict some of the most common assumptions on the benefits of spatial industrial clustering, that have been diffused in the literature. more...
- Published
- 1997
- Full Text
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45. Study on Total Quality Management Activities in Taiwan Tourism Factories
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Yi-Chan Chung
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Total quality management ,business.industry ,020209 energy ,Questionnaire ,Information technology ,02 engineering and technology ,lcsh:Business ,Competition (economics) ,Order (business) ,0202 electrical engineering, electronic engineering, information engineering ,Business ,Marketing ,lcsh:HF5001-6182 ,Set (psychology) ,Operational strategy ,Information technology, operational performance, operational strategy, total quality management ,Tourism - Abstract
As competition becomes increasingly fierce, how to integrate the concept of information technology involvement into total quality management activities and better serve the customers, thus increasing the effectiveness of their services, has become an important focus for many tourism factories in their selection of an appropriate operational strategy. With the tourism factories in Taiwan as the subjects, this study was therefore set out to investigate the impact of operational strategies, information technology involvement and motivation on the executive degree of total quality management (TQM) activities, as well as the correlation between the executive degree of TQM activities and operational performance. This research was conducted from March to April 2016 using 56 effective questionnaires through a questionnaire survey method. According to the research findings, the higher the executive degree of TQM activities was, the more significant a positive impact it would have on operational performance; the execution of differentiation strategies would have a positive impact on the execution of TQM activities; the more a company was involved in information technology, the more significant a positive impact it would have on the execution of TQM activities; the higher the intrinsic motivation was, the more significant a positive impact it would have on the executive degrees of TQM activities. It is therefore advisable for tourism factories to implement TQM activities, adopt differentiation strategies, seek greater information technology involvement and become more strongly motivated toward TQM implementation in order to improve operational performance. more...
- Published
- 2016
- Full Text
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46. An Operations Research Approach For The Planning and Operation Of An Ambulance Service
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Pierre Trudeau, Jean Choquette, Jean-Marc Rousseau, and Jacques A. Ferland
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021103 operations research ,Operations research ,business.industry ,Computer science ,0211 other engineering and technologies ,Scheduling (production processes) ,02 engineering and technology ,Demand forecasting ,Computer Science Applications ,Signal Processing ,0202 electrical engineering, electronic engineering, information engineering ,Emergency medical services ,Ambulance service ,020201 artificial intelligence & image processing ,Operations management ,Minification ,business ,Relocation ,Operational strategy ,Information Systems - Abstract
The operation of emergency medical services (ems) is very complex, involving not only medical but financial and legal factors as well. The problem has many facets, that can be briefly summarized as follows: 1) demand forecasting; 2) conversion of demand into number of vehicles in service; 3) scheduling of personnel; 4) operational strategy, including location, dispatching, relocation of free units and anticipation of future events; 5) minimization of delays, and 6) personnel issues. This paper presents a solution model aimed at four principal areas: demand forecasting, scheduling, optimal location of waiting points and simulation as an evaluation tool. (a) more...
- Published
- 1989
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47. Optimal Operational Strategy in Nuclear Fuel Management
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P. Fornaciari, T. Mazzanti, and P. Civita
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Nuclear and High Energy Physics ,Nuclear fuel ,Fuel cycle ,business.industry ,020209 energy ,02 engineering and technology ,Condensed Matter Physics ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Nuclear Energy and Engineering ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,Process engineering ,business ,Operational strategy - Published
- 1972
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48. Energy management and techno‐economic assessment of a predictive battery storage system applying a load levelling operational strategy in island systems
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Nikos Nikolopoulos, Petros Iliadis, Konstantinos Atsonios, Stefanos Ntomalis, Panagiotis Grammelis, and Athanasios Nesiadis
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Renewable Energy, Sustainability and the Environment ,Levelling ,Computer science ,Energy management ,020209 energy ,Load forecasting ,Energy Engineering and Power Technology ,Techno economic ,02 engineering and technology ,Battery Energy Storage System ,021001 nanoscience & nanotechnology ,7. Clean energy ,Battery energy storage system ,RES forecasting ,Automotive engineering ,Peak Shaving ,load levelling ,Load Forecast ,Fuel Technology ,Nuclear Energy and Engineering ,Battery storage system ,Peaking power plant ,0202 electrical engineering, electronic engineering, information engineering ,0210 nano-technology ,Operational strategy - Abstract
In the present study, a predictive battery energy storage system (BESS) for application in geographical non‐interconnected islands with high renewable energy penetration is proposed, capable of performing load levelling. The system under consideration is composed of diesel and heavy oil generators, a photovoltaic farm, and a small wind turbine. The proposed solution integrates machine learning (ML) methods for the forecasting of load and intermittent solar and wind power productions, alongside a custom scheduling algorithm, which calculates the necessary BESS setpoints that accomplish the desired levelling effect. An important feature of the scheduling algorithm is that the charge and discharge energy amounts of each day are by design equal and independent of the forecasts’ accuracy. This aspect enables economic investigations to identify the appropriate BESS capacity for the particular system, also taking into account the battery's capacity degradation. The overall system is modelled and simulated utilizing the open‐source languages Python and Modelica. Simulations presented a 9.8% peak‐to‐mean ratio (PMR) reduction of the thermal plant's load. Furthermore, economic investigations estimated a marginal BESS cost of 287.1 €/kWh revealing the financial viability of the proposed integrated system, in at least the case of geographical islands. more...
- Full Text
- View/download PDF
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