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Wastewater treatment plants (WWTP) are required to meet increasingly stringent effluent quality standards as well as to improve process sustainability in terms of energy efficiency, in line with the call for a paradigm shift towards the more sustainable concept of wastewater resource recovery facility (WRRF). In this context, optimised Instrumentation, Control and Automation (ICA) systems as well as process and plant-wide modelling have become key tools for optimising economic and environmental costs. The present work reports on the successfull integration of an innovative on-line continuous titrimeter and plant-wide modelling as a support tool for the optimisation of the nitritification unit in a large-scale industrial WWTP. The information gathered from the on-line titrimeter allowed for real-time estimation of the Ammonia Oxidation Rate of the activated sludge and, ultimately, of the nitrification residual capacity of the plant. Results on the titrimeter long-term operation and historical data modelling supported plant managing decisions, such as lowering the dissolved oxygen (DO) set-point of the oxidation unit, straightforwardly resulting in energy saving. Graphical abstract

It is vital to investigate the system dynamics (SD) between change orders and labor productivity to identify the causes of productivity loss in construction projects. Most productivity loss studies are financed by the contractor and rely on the contractor’s data. There is a gap in the literature concerning the labor productivity impacts of change orders on the part of the owner. This research utilizes a previously developed SD model to highlight the problem of productivity loss resulting from issuance of a change order. We conducted a sensitivity analysis to evaluate the impact of overtime, overmanning, temperature, and learning on the behavior of the SD model quantifying change orders’ impact on labor productivity when their effects are simulated. Based on the results, SD is more reliable than the measured mile analysis (MMA) approach for the compensation request, considering the leading factors affecting the productivity loss other than the change order. The model developed in this study can accept or reject the responsibility of a change order for the occurrence of productivity loss.

In this paper, the dynamic modelling of the thermal behaviour and the electrical characterisation of a PV module are presented. The simulation results of the prediction of the PV module internal te...

Depok beach is a tourism destination located in Yogyakarta's south coastal area with its unique attractions. The tourism development at Depok beach finds some problems, especially on tourism sustainability. This research tried to model a system for managing Depok beach as a sustainable tourist attraction. System dynamics were used for modeling the management strategy. The data of this study were gathered by doing observation and in-depth interviews with related stakeholders. This research found that the Depok beach management model is a complex system consisting of social, economic, and ecological subsystems. The management system of Depok beach was quite nice, even one environmental aspect, which is waste management was not fully appropriate. Locals waste management was done traditionally, neglecting any ecological problems that may be occurred. The optimization of Depok beach management might be achieved by strengthening the waste management system.

In this research work a self-driving wheelchair Self-E is designed and implemented. The wheelchair can be used for indoor navigation and it can help elderly and differently abled people on a day-to-day life. With an Android app developed for Self-E, the user can specify destination coordinates just by touching on the screen of his/her electronic gadget. It takes the user to the destination without the need for continuous control like using joystick till the destination is reached. The research involves the dynamic modelling, design, simulation of the model in ROS Gazebo, implementation and testing of the wheelchair. With extensive experiments that demonstrate the performance and accuracy of the system, testing with patients, and users experience indicate that Self-E could be a better option compared to a joystick controlled powered wheelchairs for certain category of users.

Agriculture as a key industry for human food suply will face various concerns in near future. This research is complementary and aims to present the dynamic modelling and simulation, as well as algorithm development of a 4-DOF SCARA-type robotic arm designed for real agricultural cultivation process, such as seeding, watering, fertilizing, weeding, etc. In terms of a previously designed system, the equations of motion profile were solved (acceleration and deceleration control of joints) to reduce inertia, ensure a smooth motion, and minimize torque requirement. The algorithm is evaluated by PTP motion, TCP linear motion, and spline motion. The results show that the developed algorithm can move the TCP using ST-profile. Furthermore, it can control all joints for an estimated time duration. A novel method was developed to manoeuvre the TCP along the shortest path to reach a goal point. Finally, the algorithm was evaluated in a closed path inside the working space.

Automatically and accurately obtaining payload information from Load-Haul-Dump (LHD) vehicles is a typical application of information and intelligence technology in engineering equipment, which provides an important support for efficient and safe construction. In this paper, a novel comprehensive weighing model for LHD with high accuracy and adaptability is proposed by Newton-Euler method. The accuracy of the model has been greatly improved with the consideration of some critical factors such as materials randomness, driving cylinders coupling, dynamic characteristics of mechanism, system damping and working pavement. The effect of the critical factors on the accuracy of weighing model is deeply analysed through significance analysis and comparison tests, which provides an important basis for the improvement of weighing model. Validation shows that the novel model is superior to traditional models in accuracy and adaptability. In theory, the accuracy of novel model is at least 3 times higher than that of traditional models, and its accuracy can still achieve ±0.3% in complex velocity or acceleration motion, and the larger the load mass, the higher the accuracy. As a result, the novel comprehensive weighing model can provide accurate load information for LHD vehicles without affecting working efficiency. It is of great theory and application value to the development of information and intelligence technology in engineering equipment and contributes to efficient and safe construction.

The large number of distributed generators, storages, and other devices which might be connected to the distribution grid pose significant modelling and control questions. It is computationally unattractive and sometimes infeasible to model and control all these devices individually; some method of aggregating them both for modelling and for control is appealing so that they can be represented collectively. It would also be preferable to limit the complexity of the controlled devices' dynamic behavior for easy integration with higher‐level (i.e., higher‐authority) controllers in the cascade. This paper describes a method combining these control goals based on geometric flexibility regions, constrained optimization, and transfer function considerations to enforce approximated first‐order transfer function behaviour at the bus. Time‐domain simulations are used for validation and demonstration.

This paper discusses the dynamic modelling of a solar energy system with vehicle to home (V2H) option for Newfoundland condition. A location was chosen (13 Polina Road) in St. John’s, Newfoundland, Canada. Using BEopt, Homer and MATLAB software, an optimized system was designed for the chosen site to satisfy the house’s energy demand. Furthermore, the concept of V2H is also implemented with aid of smart current sensors installed in the house. When the power provided by the PV panel and the stored energy in the inhouse battery is less than the load’s energy demand, the Nissan Leaf’s battery used to supply home loads in V2H operation mode. The system operates based on the information generated by the sensors. Detailed system dynamic modelling is also presented along with the simulation results. Eight system control modes are proposed and simulated.

[Abstract] Dynamic models typically have unknown parameters that must be estimated from data, and they may also have unknown inputs (disturbances). The concept of observability, which describes the possibility of inferring the internal state of a system by measuring its output, can be extended to account also for the possibility of inferring its unknown parameters and inputs. Such an extension leads to a property that may be called FISPO (Full Input, State, and Parameter Observability). Its analysis is particularly relevant in systems biology, since models from this area often have a large number of unknown parameters, as well as state variables that cannot be measured due to experimental limitations. It is usually challenging to assess the FISPO of nonlinear models, which has motivated the development of specialized software such as the MATLAB toolbox STRIKE-GOLDD. However, despite the increasing popularity of Python among the biological modelling community, there was a lack of computational tools for FISPO analysis in this language. To fill this gap, we have developed an open source software toolbox, StrikePy, which implements the core functionalities in STRIKE-GOLDD. Ministerio de Ciencia e Innovación; 10.13039/501100011033 This work has received funding from MCIN/AEI/10.13039/501100011033 through grant PID2020-113992RA-I00 (PREDYCTBIO), from the Xunta de Galicia, Consellería de Cultura, Educación e Universidade through grant ED431F 2021/003, and from grant RYC-2019-027537-I funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future”. Ministerio de Ciencia e Innovación; 10.13039/501100011033 Xunta de Galicia; ED431F 2021/003

Trabajo presentado en el 8th Symposium on Hydrogen, Fuel Cells and Advanced Batteries, celebrado en Buenos Aires (Argentina), del 10 al 13 de julio de 2022, On-site and on-demand hydrogen production from liquids has been gaining more attention in recent years. For that purpose, it is recommended to use low temperature processes and compact reformers which make methanol a good candidate because methanol does not involve the cleavage of C-C bonds and the reforming can be done at low temperature [1]. Catalytic membrane reactors are a good choice for a compact reforming unit since they have the production, separation and purification phase in the same reactor volume, This work has been funded by projects MICINN/FEDER RTI2018-093996-B-C31, GC 2017 SGR 128 and RTI2018- 096001-B-C32. AC grateful to Generalitat de Catalunya and Addlink Software Científico S.L. for Industrial Doctorate grant 063/2018. JL is a Serra Húnter Fellow and is grateful to ICREA Academia program. We are grateful to Vicente Roda, Alejandro Martinez and Isabel Serrano (EEBE) for technical assistance.

Formulation of the problem. Dry friction dampers are widely used for the protection of buildings from dynamic and seismic loads. Their advantages are the simplicity and reliability of the design, low costs, easy installation and maintenance, as well as high dissipative characteristics. Determining the location of friction dampers inside a building is a complex task that requires a comprehensive analysis of the dynamic properties of the structure and, as a rule, cannot be solved within the framework of standard design methods. Therefore, a crucial problem is the development of novel methods for calculating structures with dry friction dampers allowing finding optimal design solutions to minimize dynamic and seismic impacts. The purpose of the sudy. The method of particle swarm optimization is developed for the prediction of rational locations of friction dampers in multi-storey frame buildings to enhance their resistance to seismic loads. Conclusions. An analytical model describing the dynamic behavior of buildings with friction dampers is proposed. A mathematical model of seismic loads is developed. Non-stationary vibrations of a building under the seismic loads are investigated. The governing non-linear dynamical equations are integrated numerically by the Runge-Kutta method. The rational locations of friction dampers are determined ensuring the minimal inter-storey drifts and accelerations of the building. The obtained results can be used in the design of houses and structures with enhanced resistance to seismic and dynamic impacts.

Power-to-gas is a pathway for the storage of intermittent renewable energy in a chemical form; energy surpluses can be exploited to produce hydrogen (via electrolysis) that can then react with carbon dioxide to produce synthetic methane by using catalytic cooled reactors. Methanation unit has been designed and optimized, defining the number of involved reactors, the number of parallel tubes for each reactor and the staged CO2 injection to moderate the maximum temperature throughout the reactors. The produced synthetic natural gas (SNG) must have a methane content at least equal to 95 mol.-%, achieved by involving a series of 3 cooled reactors. Dynamic behavior of the as-designed system has been investigated for two cases that can occur when a power-to-gas system is operated intermittently: start-up from reactor hot standby and system operated at partial load. Methanation system requires about 130 s to reach the targeted methane content when it is started up from hot standby. In order to broaden the system rangeability (the minimum percentage of full load), different CO2 staged injection should be carried out: part of carbon dioxide bypasses first and second reactor and it is directly conveyed to the third one.

This study uses a dynamic modelling approach to group clients of a microcredit programme in Brazil and follows them over time. Five segments are identified based on variables related to business, owners, families and operations performed within the programme. Results show that borrowers' circumstances are diverse and different actions are needed for each group. Many customers remained in the same segment; some moved to segments with worse conditions. However, the fact that one fourth of borrowers improved conditions is promising, considering the risky nature of entrepreneurial activity and the Brazilian economic context. Our analyses show that mission drift does not occur.

Detailed dynamic modelling of a solar sail requires recording of solar radiation pressure influence. A photon-solar sail is determined by the thrust value and the direction. We define the solar sail’s reflectivity depending on the film materials, the sail design and temperature, the thickness of multiple layers, and degradation factor, with a reasonable degree of accuracy. Thus, this work is devoted to the identification of optical characteristics of thin multilayer films in space flight conditions, i.e. to finding its reflectance, absorbance, and transmittance. In particular, the paper asks whether the solar sail simulates by a mathematical model of the optical characteristics of a multilayer epitaxial thin film. The temperature change effect and optical properties of solar sail degradation are considered as well. Solar sail flight from Earth to Mercury is designed as a simulation of the flight change in optical parameters.

For railway locomotive, its motor bearing is one of the key components, which is likely to be damaged due to the intensified vibration conditions caused by the wheel-rail interaction and gear mesh....

In this paper, the dynamic modelling and adaptive boundary control of a three-dimensional Timoshenko beam are presented for vibration suppression. In order to ensure that no modal information is le...

ObjectiveFor recalcitrant chronic maxillary sinusitis, modified endoscopic medial maxillectomy has been shown to be clinically beneficial after failed maxillary antrostomy as endoscopic medial maxillectomy may offer improved topical therapy delivery. This study compared irrigation patterns after maxillary antrostomy versus endoscopic medial maxillectomy, using computational fluid dynamic modelling.Case reportA 54-year-old female with left chronic maxillary sinusitis underwent maxillary antrostomy, followed by endoscopic medial maxillectomy. Computational fluid dynamic models were created after each surgery and used to simulate irrigations.ResultsAfter maxillary antrostomy, irrigation penetrated the maxillary sinus at 0.5 seconds, initially contacting the posterior wall. The maxillary sinus was half-filled at 2 seconds, and completely filled at 4 seconds. After endoscopic medial maxillectomy, irrigation penetrated the maxillary sinus at 0.5 seconds and immediately contacted all maxillary sinus walls. The maxillary sinus was completely filled by 2 seconds.ConclusionComputational fluid dynamic modelling demonstrated that endoscopic medial maxillectomy allowed faster, more forceful irrigation to all maxillary sinus walls compared with maxillary antrostomy.

Connected and automated vehicle (CAV) technologies and services are rapidly developing and have the potential to revolutionise the transport systems. However, like many innovations, the uptake pathways are uncertain. The focus of this article is on improving understanding of factors that may affect the uptake of highly and fully automated vehicles, with a particular interest in the role of the internet of things (IoT). Using system dynamic modelling, sensitivity testing towards vehicle attributes (e.g., comfort, safety, familiarity) is carried out and scenarios were developed to explore how CAV uptake can vary under different conditions based around the quality of IoT provision. Utility and poor IoT are found to have the biggest influence. Attention is then given to CAV ‘services' that are characterized by the attributes explored earlier in the paper, and it is found that they could contribute to a 20% increase in market share.

This study addresses the use of former gas storage facilities as short-term storage for renewable energy through power-to-gas (PtG) technology in Germany. Three test cases with coupled thermal-hydromechanical (THM) modelling were conducted to evaluate short-term injection and production schedules. The operating rates were controlled by the upper and lower limits of the wellbore pressure. The maximum difference in pore pressure and effective stress was 0.6 MPa in all cases. Fault reactivation analysis was performed on the THM models to estimate fault stability. The critical pore pressure for safe reservoir operation was determined to be 1.25 times the original pore pressure, corresponding to a WBHP value of 20.25 MPa. The upper limit of the gas injection rate for safe storage operation was estimated to be between 100,000 and 150,000 m3/day. The thermal stresses were found to be negligible for short-term cases. The storage capacity of PtG technology was reported to be up to 1,322,400 kWh/d of renewable electricity, which can contribute to Germany becoming a greenhouse gas neutral country by 2050. The workflows and results of the study are applicable to all gas storage in a porous medium, including methane, CO2, and hydrogen.

Since asphalt mortar is highly heterogeneous and occurs as an interfacial bonding material between the asphalt-binder and aggregate, it is very important to have a detailed and adequate understandi...

This article presents a novel hybrid algorithm based on the grey-wolf optimizer and whale optimization algorithm, referred here as grey-wolf optimizer–whale optimization algorithm, for the dynamic parametric modelling of a four degree-of-freedom master–slave robot manipulator system. The first part of this work consists of testing the feasibility of the grey-wolf optimizer–whale optimization algorithm by comparing its performance with a grey-wolf optimizer, whale optimization algorithm and particle swarm optimization using 10 benchmark functions. The grey-wolf optimizer–whale optimization algorithm is then used for the model identification of an experimental master–slave robot manipulator system using the autoregressive moving average with exogenous inputs model structure. Obtained results demonstrate that the hybrid algorithm is effective and can be a suitable substitute to solve the parameter identification problem of robot models.

Nowadays, vehicles with alternative drives are playing an increasingly important role in road transport. Among the various types of alternative-drives, the most widespread ones are hybrid and electric ones, thanks for the rapid development of modern batteries, and hybrid and electrical systems. The above fact establishes the importance of research on various types of electric motors. The Faculty of Engineering of the University of Debrecen has more than a decade of experience in developing prototype race cars with pneumatic and electric drive. For the more effective and conscious development and racing a simulation program has been developed in MATLAB/Simulink environment for the computation of the dynamic functions of a vehicle moving in a linear path. The program is characterized by a modular structure, so the different structural units (vehicle body, front and rear wheels, power train, motor) are modelled and simulated separately. In this study we present models and simulation programs for different electric motor types (series-wound DC and brushless DC motors) in MATLAB/Simulink and apply them in our vehicle dynamics simulation program. From the simulation results the performance of a vehicle – driven by an electric motor – can be predicted in a race situation, consequently the most suitable motor with the optimal characteristics can be selected to it.

A dynamic model of a multi-unit air conditioning (AC) system in a generic bus was developed to investigate different control strategies on the system performance and the cabin comfort level. In this study, a part-load condition was considered, where adopting a proper strategy for governing a multi-unit system is important. Simulink and Simscape toolbox from MATLAB (R2019a) were used to build up the real-time model by integrating a cooling system with a cabin sub-model. The cooling system consists of two independently controlled units, based on a Vapor Compression Cycle (VCC).The cabin is modelled using a moisture air network and is coupled with the cooling system to exchange heat with the refrigerant through the evaporators. Moreover, the sensible and latent loads are incorporated into the cabin by a thermal network. Six different strategies were implemented using different criteria to investigate the average power and Coefficient of Performance (COP) under a part-load condition. The comfort level was obtained in terms of the Predicted Mean Vote (PMV)and Predicted Percentage of Dissatisfied (PPD) indices. Results are suggestive of a link between the implemented control strategy of a multi-unit AC system and its performance. Results showed that five out of the six proposed strategies might be chosen, depending on the adopted trade-off policy between the comfort level and the system energy demand. In this way, the numerical approach introduced here, along with the combination of the presented findings, provides good support for the decision-making on thermal management inside the cabin, based on the energy consumption and the thermal comfort level.

Transmission error is an important excitation source of gear transmission system. In many previous dynamic models, the transmission error is often treated as a simple harmonic function, ignoring the difference among transmission errors caused by different deviations. In fact, each kinds of gear deviation may lead to transmission error with different characteristics, which has different influence on the dynamic characteristics of the system. To analyze the effect of different deviations on dynamic characteristics, it is necessary to explore the characteristics of each deviation and transmission error. This paper takes the profile deviation as the research object and, by analyzing its characteristics, builds the mathematical model of spur gear tooth surface including tooth profile deviation. Based on tooth contact analysis (TCA), the characteristics of transmission errors caused by different factors of tooth profile deviation are analyzed and then the influence of different factors of tooth profile deviation on the dynamic characteristics of spur gear system is discussed. To verify the rationality of the dynamic model, the simulation results are compared with the results in the previous literature. The simulation results show that the effect of these factors of tooth profile deviation on the system is obviously different and it is necessary to consider their comprehensive effect for improving the accuracy of dynamic models. The modelling and analysis method based on TCA in this paper has practical guiding significance for analyzing the influence of different deviations caused by manufacturing and assembling on the dynamic characteristics of gear system.

This study establishes a dynamic modelling for site-related credits. Guidelines of the ‘Leadership in Energy and Environmental Design’ (LEED) system are used for the context and project levels unde...

Round link chain drives can be sorted into the transmission, parallel conveyor and non-parallel conveyor systems according to their applications and guide rail’s layouts. The polygonal action in these systems is irregular. Compared with the literature, this paper proposes a more accurate modelling approach to capture the dynamic behaviour of round link chain drives, which can consider both the irregular polygonal action and non-parallel guide rail’s layout. The dynamic models of the three types of round link chain drives are developed based on the finite segment method. The chain is divided into multiple discrete segments that are connected by Kelvin models. To account for the irregular polygonal action, the sprocket is equivalent to an irregular polygon. To consider the non-parallel guide rail’s layout in the conveyor system, the chain segment out of the guide rail and the corresponding sprocket are treated as a swinging-block mechanism. The proposed approach is applied to model a scraper conveyor. Simulation results show that the irregular polygonal action and non-parallel guide rail’s layout greatly increase the fluctuation of the chain tension force.

In order to understand and to predict cable effects on structures, three-dimensional numerical models for a stranded cable and a beam–cable system consisting of a cantilever beam and two connected ...

Biotechnology applications have contributed significantly to “factory in a lab” research. Although the largely adopted Design–Build–Test–Learn cycle has considerably improved synthetic biology and metabolic engineering capabilities, we are still far from achieving industrial efficiency. As we are now faced with the challenge of exponential population growth and drastic climatic changes affecting the traditional agriculture, there is an imminent need to optimize biotechnology applications, especially for the alternative food source initiative, which has received immense attention recently. Here, I highlight the importance of multi-disciplinary research, and the need to develop integrated systems biology methods, using high-throughput omics data, dynamic modelling and machine learning techniques, to further enhance the lab-based production process. Moving forward in this direction will likely reduce the overall cost and increase the output for the longer term future.

PurposeA construction project is complex and requires dynamic modelling of a range of factors that deters time performance because of uncertainty and varying operating conditions. In construction project systems, the system components are the interconnected stages, which are time-dependent. Within the project stages are the activities which are the subsystems of the system components, causing a challenge to the analysis of the complex system. The relationship of construction project time management (CTM) with the construction project time influencing factors (CTFs) and the adaptability of the time-varying system is a key part of project effectiveness. This study explores the relationship between CTM and CTF, including the potentials to add dynamical changes on every project stage.Design/methodology/approachThis study proposed a dynamic Bayesian network (DBN) model to examine the relationship between CTM and CTF. The model investigates the time performance of a construction project that enhances decision-making. First, the paper establishes a model of probabilistic reasoning and directed acrylic graph (DAG). Second, the study tests the dynamic impact (IM) of CTM-CTF on the project stages over a specific time, including the adaptability of time performance during disruptive CTF events. In demonstrating the effectiveness of the model, the authors selected one-organisation-single-location road-improvement project as the case study. Next, the confirmation of the model internal validity relied on conditional probabilities and the project knowledge experts' selected from the case company.FindingsThe study produced structural dependencies of CTM and CTF with probability observations at each stage. A predictive time performance analysis of the model at different scenarios evaluates the adaptability of CTM during CTF uncertain events. The case demonstration of the model application shows that CTFs have effects on CTM strategy, creating the observations to help time performance restorations after disruptions.Research limitations/implicationsAlthough the case company experts' panel confirms the internal validity of the results for managing time, the model used conditional probability table (CPT) and project state values from a project contract. A project-wide application then will require multi-case data and data-mining process for generating the CPTs.Practical implicationsThe study developed a method for evaluating both quantitative and qualitative relationships between CTM and CTF, besides the knowledge to enhance CTM practice and research. In construction, the project team can use model observations to implement time performance restorations after a predictive or reactive disruption, which enhances decision-making.Originality/valueThe model used qualitative and qualitative data of a complex system to generate results, bounded by a range of probability distributions for CTM-CTF interconnections during time performance disruptions and restorations. The research explores the approach that can complement the mental CTM-CTF modeling of the project team. The CTM-CTF relationship model developed in this research is fundamental knowledge for future research, besides the valuable insight into CTF influence on CTM.

This paper provides the review and prototype development of mecanum wheels mobile robot (MWMR). Nowadays, there is a high market demand for a wheeled machine or wheeled robot for various applications. The ability to move in any direction without altering even a single wheel makes this type of wheel useful for driving, especially in a narrowed or confined space. Various styles of implementing MWMR are discussed in this paper. The kinematic derivation and dynamic modelling are also presented. Characteristically, mecanum wheels face traditional mobile application issues like jerking and slippage, contributing to low positioning accuracy and repeatability. Besides, environmental factors like disturbance and uncertainty also contribute to these issues. The control strategies in previous research have been reviewed and presented in this paper to reduce the effect. Finally, a low-cost prototype of MWMR was developed as an experimental platform for future study.

Tourism is an important economic driver and plays a critical role in the economic development of South Asian countries. However, tourism also brings about some inevitable consequences on the environmental quality of these countries. Using the Autoregressive Distributed Lags, Vector Error‐Correction Model and Panel frameworks, we investigate the inter‐relationships between tourism, energy consumption, CO2 emissions and gross domestic product (GDP) in South Asia, using data for the period 1990–2014. We find that, in the long‐run, tourism positively contributes to GDP, CO2 emissions and to the demand for energy; an increase in GDP improves tourism; and an increase in CO2 levels is not a deterrent for tourists to visit South Asia.

Summary Our insight into the pathogenesis of cholestatic liver disease remains limited, partly owing to challenges in capturing the multitude of factors that contribute to disease pathogenesis in vitro. Tissue engineering could address this challenge by combining cells, materials and fabrication strategies into dynamic modelling platforms, recapitulating the multifaceted aetiology of cholangiopathies. Herein, we review the advantages and limitations of platforms for bioengineering the biliary tree, looking at how these can be applied to model biliary disorders, as well as exploring future directions for the field.

Purpose The primary purpose of this study is to show and guide how to construct a large variety of behaviors in systems dynamic for sport science. Methods By applying a simple algorithm to networked agents, which could, conceivably, offer a straightforward way out of the complexity, computational mechanism which along with its dynamics (payoff, failure, and strategy) involved. Results The model starts with the probability that systemic risk potential such as failure spreads. Even in a very random structure commonly used in sports field, propagation of the potential is guaranteed by an arbitrary network property of a set of elements. Despite the intensive systemic potential, the opposite type of potential like absence of failure could also be driven when there has been a strong investment in protection through a heuristically evolved protection level. Conclusion The implementation still needs to be polished against what happens in the real sports world, but in general, applied conceptual principle and methodological techniques behind the network-agent based mechanisms could be useful for researchers those who need to use systemes dynamic to guard in sport science.

The automatic identification of cardiac condition through dynamic modelling of electrocardiogram (ECG) signal has immense clinical significance as it eliminates the task of manual annotation of ECG recordings. In this study, an interacting multiple model (IMM)-based scheme has been proposed that helps in dynamically modelling and estimating the ECG signal. This model is having the adaptability of interchanging among several morphological representations. It offers the advantage of not necessitating user-specific parameters. This model does not necessitate a priori information about the ECG signal to initialise the filter parameters and delimitation of fiducial points of ECG signal. The particle filter (PF)-based schemes show superiority owing to their freedom from a single assumption on the signal model and noise model. Besides, it has got the potential of simultaneously tracking multiple pathological and morphological changes occurring in biomedical signals. Thus, the parameters of the model are estimated by adopting the PF, so that the myocardial infarction (MI) affected ECG signals can be efficiently tracked. Investigations on ECG signals from the MIT-BIH database and PTB diagnostic ECG database signify that the IMM-PF scheme can represent several MI morphologies with minimum prior information without distorting the helpful diagnostic information of ECG accurately.

To solve the problem of uncertain parameters in dynamic modelling of upper-limb rehabilitation robots, a dynamic parameter identification method based on variable parameters particle swarm optimisation (PSO) is developed. Based on the dynamic model of the system, the algorithm changes the inertia parameter and learning law of the basic PSO algorithm from the fixed-parameter to the function that changes with the number of iterations. It solves the problems of small search space in the early stage and slow convergence speed in the later stage of the basic PSO algorithm, which greatly improves its identification accuracy. Finally, through the comparison and analysis of the simulation results, compared with those of the least square (LS) and unmodified PSO identification algorithms, a great improvement in the identification accuracy of the algorithm is achieved. The control effect in the actual control system is also much better than those of the LS and PSO algorithms.

The damping properties of a commercial polymer concrete are the subject of this application-driven study, which is aimed to investigate the material suitability as a filler of machine bed components to limit vibrations arising in machine tools and automatic machines working at high dynamics. Two main goals are targeted: ( i) quantitative evaluation of the elastodynamic effects due to the polymer concrete insertion into typical components of machine beds, in order to effectively assess its practical potential and ( ii) determination of reliable models of the material, needed to simulate the dynamic response of new design solutions of machines featuring structural components filled with the polymer concrete. The paper is mainly focused on the methodological approach of both the experimental campaign and the signal processing that were carried out. Based on the promising results achieved, the possible use of the polymer concrete as a viable solution to enhance the dynamic behavior of an automatic machine is finally investigated and discussed as a case study.

This paper discusses cooperative path-planning and tracking controller for autonomous vehicles using a distributed model predictive control approach. Mixed-integer quadratic programming approach is used for optimal trajectory generation using a linear model predictive control for path-tracking. Cooperative behaviour is introduced by broadcasting the planned trajectories of two connected automated vehicles. The controller generates steering and torque inputs. The steering and drive motor actuator constraints are incorporated in the control law. Computational simulations are performed to evaluate the controller for vehicle models of varying complexities. A 12-degrees-of-freedom vehicle model is developed and is subsequently linearised to be used as the plant model for the linearised model predictive control-based tracking controller. The model behaviour is compared against the kinematic, bicycle and the sophisticated high-fidelity multi-body dynamics CarSim model of the vehicle. Vehicle trajectories used for tracking are longitudinal and lateral positions, velocities and yaw rate. A cooperative obstacle avoidance manoeuvre is performed at different speeds using a co-simulation between the controller model in Simulink and the high-fidelity vehicle model in CarSim. The simulation results demonstrate the effectiveness of the proposed method.

Although obsessive compulsive disorder (OCD) is effectively treated by cognitive behavior therapy (CBT), less is known about mechanisms underlying treatment response. Anxiety sensitivity (AS) may impact symptom change (velocity) and the rate of change in velocity (acceleration) during CBT for OCD. Latent Difference Score (LDS) analysis was used to show path-analytic dynamic modelling of OCD symptom velocity and acceleration during CBT, as a function of baseline AS. Eighty-four participants with a principal diagnosis of OCD completed 12 weeks of CBT group therapy, and measures assessing AS at pre-treatment, and obsession and compulsion severity at pre-treatment, sessions 4, 8, and end of treatment. LDS velocity models demonstrated that higher levels of baseline AS were associated with subsequent elevations in obsessions throughout treatment, and obsession scores were temporally associated with subsequent changes in compulsion scores. An LDS acceleration model demonstrated that higher levels of baseline AS scores were associated with rapid increases in the severity of obsessions, whereas lower AS scores were associated with rapid decreases in the severity of obsessions. These results have implications for theoretical and treatment modelling of obsessions and compulsions, as well as AS, in OCD. Higher levels of baseline AS negatively impact response to CBT for OCD.

The current healthcare system in Hong Kong is experiencing pressure due to constrained resources, with dramatic increases in inpatient services queue lengths, dissatisfaction with the working environment, unacceptable workforce arrangements and high turnover rate of hospital staff. To maintain the robustness of the healthcare system and a sustainable inpatients flow, the Food and Health Bureau launched a public-private partnership programme to utilise the resources of the public and private hospitals. This research investigates the potential for extension of the programme and further enhancing the sustainability of the long-term inpatient services under a mixed public-private healthcare policy via system dynamic modelling. The findings show that an increase of human resources in public hospitals does not substantially improve inpatient flow rate performance. Further, the results from the system dynamic approach provide insights into the expansion of the service areas of the programme and suggest increasing the number of referrals to private hospitals. Nanyang Technological University The research was supported by the Hong Kong Polytechnic University, Hong Kong and Nanyang Technological University, Singapore. Our gratitude is also extended to the Research Committee and the Department of Industrial and Systems Engineering of the Hong Kong Polytechnic University for supporting this project (G-UA7X).

Existing literature argues that the mortality rate of a specific age is affected not only by its own lags but by the lags of neighbouring ages, known as cohort effects. Although these effects are a...

The paper presents the authors’ estimations according to the scoring modeling techniques; also, internationally spread models of bankruptcy forecasting are systematized. Advantages and disadvantages of dynamic modelling methods as applied to financial condition assessment are presented here. Methodological problems of financial modelling are explained here in detail. Regression, logit-regression and discriminant models are built on the basis of data on the Rosselkhozbank and Sberbank of Russia regulations, taking into account the agrarian specifics of organizations and regional specificity of the Omsk region. An attempt has been made to balance the simplicity of calculations and the accuracy of predictions. Graphs, to be used for express analysis, are constructed on the basis of two core financial indicators.

This paper explores the development of dynamic modelling of macroeconomic fluctuations at the Cowles Commission from Roos, Dynamic Economics (Cowles Monograph No. 1, 1934) and Davis, Analysis of Economic Time Series (Cowles Monograph No. 6, 1941) to Koopmans, ed., Statistical Inference in Dynamic Economic Models (Cowles Monograph No. 10, 1950) and Klein’s Economic Fluctuations in the United States, 1921-1941 (Cowles Monograph No. 11, 1950), emphasizing the emergence of a distinctive Cowles Commission approach to structural modelling of macroeconomic fluctuations influenced by Cowles Commission work on structural estimation of simulation equations models, as advanced by Haavelmo (“A Probability Approach to Econometrics,” Cowles Commission Paper No. 4, 1944) and in Cowles Monographs Nos. 10 and 14. This paper is part of a larger project, a history of the Cowles Commission and Foundation commissioned by the Cowles Foundation for Research in Economics at Yale University. Presented at the Association Charles Gide workshop “Macroeconomics: Dynamic Histories. When Statics is no longer Enough,” Colmar, May 16-19, 2019.

In this paper, a mathematical model is presented to numerically simulate the dynamical responses in a multi-cable suspension platform taking into account the slack cables and guiding devices. The s...

Over the last few years, some novel researches in the field of medical science made a tendency to have therapy without any complications or side-effects of the disease with the aid of prognosis about the behaviors of the microtubules. Regarding this issue, the stability/instability analysis of curved microtubule-associated protein in axons with attention to different size effect parameters based on an exact continuum method is presented. The real property of the living biological cells is presented as the Kelvin-Voight viscoelastic properties. Considering length scale parameter (

Linear guideways play a crucial role in determining precision of machine tools. Understanding their dynamic response is essential for objectively controlling their behavior and performance in operation. Due to highly loaded lubricated contacts, mixed-elastohydrodynamic regime is dominant. The mixed-elastohydrodynamic film maintains the coupling between horizontal degree of freedom (feed velocity) and vertical degree of freedom (loading direction). This paper presents a novel tribo-dynamic solution for linear guideways, taking in to account the lubricant effects and coupling between horizontal and vertical degrees of freedom. An analytical tribology model is used implicitly within the dynamic model. For in-depth tribological quantities including pressure and film thickness distribution, an explicit full numerical solution for mixed-elastohydrodynamic is utilized. Results show that the coupled solution of vertical and horizontal degrees of freedom taking in to account lubricated contacts is essential. It is shown that at moderate and light loads, the effect of this coupling and presence of lubricant is more pronounced.

Purpose The purpose of this study is to investigate the dynamic behavior of the ball bearing with cage broken. Design/methodology/approach By analyzing the complicated relationship and interactions among the ball bearing elements, the dynamic modelling of the ball bearing with broken cage was established, and the dynamic simulations were conducted by solving the ball bearing dynamic equations using varying-step Runge–Kutta integration. Findings The computational results show that there is considerable distinguishment in the dynamic characteristics between the normal cage and the broken cage of the bears. The broken cage makes the trajectory of the cage erratic, and the vibration amplitude is much bigger than that of the normal cage, which makes the motion of the cage unstable. When one of the cage lintels breaks up, the two adjacent balls will collide with each other; what is worse, this may make the balls crush because of the high amplitude of the collision force. The broken cage makes the cage-race interaction force much larger than that of the normal cage, which could promote the guiding ring and quicken the cage wear-failure. Originality/value This study can provide important ideas for the fault identification of the ball bearing with cage broken. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0042/