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In the context of project management, the attention given to project portfolio management has increased in recent years. The use of mathematical programming for portfolio management is also on the rise, because it integrates the project interactions with the multiple objectives of portfolio management into a single model. Among the possible objectives, recent studies have paid special attention to the emerging objective of future preparedness, which has not yet been incorporated into the existing mathematical models. This paper presents a mixed-integer nonlinear optimization model for portfolio selection that considers four main performance measures for project management, namely, value maximization, strategic alignment, balance, and future preparedness. Given the importance of the last measure, the purpose of this paper is to provide a more complete model that provides the marginal contribution and the best combination of projects according to the needs of the company. The model is tested using real data from two companies, one in Brazil and one in Canada, and the results obtained are coherent with their respective practices. [ABSTRACT FROM AUTHOR]

This article is an extension of a work in progress paper originally presented at the conference FiE 2020, Frontiers in Education by (Schirichian et al., 2020), as a result of Schirichian’s master’s in science dissertation. It studies the relations between academic performance, protection factors, life at university, and personal characteristics to understand how they influence students’ academic success in undergraduate engineering programs in Brazil. In this challenging environment, several students overcome these issues and graduate, which indicates that some protection structures allow students to face challenging situations and be successful in their studies. Current research studied the relationships between academic performance, self-efficacy, causal attributions, personal characteristics, and life at university, with a group of 30 students. Models were studied by combining the different variables and aspects evaluated in the research, and the findings show relationship between academic performance and: 1) self-efficacy, causal attributions, and personal characteristics (such as leisure activities, living with their parents, or college accommodations) and those who attended private schools during basic education; 2 protection factors self-efficacy and causal attributions with advancing in the program and the time of enrolment in the university; and 3) the dimensions initiation and persistence, success/internality and failure/internality, indicating that those who perceive themselves as playing a major role in their academic journey tend to have better outcomes. Further results show the influence of social inequalities, particularly for those students who declared themselves brown and who conducted their basic education in public schools (which are generally of lower quality than private ones in Brazil). [ABSTRACT FROM AUTHOR]

Remotely sensed sea-surface temperature (SST) retrievals with a significant positive bias during the occurrence of upwelling phenomena along the southeastern coast of Brazil were reported in our companion paper. As a result, this paper proposes an automated bias correction algorithm to improve the MODIS long-wave multichannel SST (MCSST) retrievals during the abovementioned conditions in this region. In this paper, MODIS daytime SST data (SSTMODIS) and differences between brightness temperatures in MODIS channels 31 and 32 (BT31 − BT32) are analyzed simultaneously with hourly wind surface conditions, in situ SST at 0.3 and 10 m in depth (SSTbuoy03 and SSTbuoy10), and sensible and latent heat fluxes from the Cabo Frio buoy data (at 23° S, 42° W) during 2014. The obtained results show that some upwelling events present air temperature ($T_{\mathrm {air}}$) greater than SSTbuoy03 and low-atmospheric water vapor content. A simultaneous occurrence of these factors during upwelling conditions may lead to a warm-skin layer effect and may cause BT31 to be greater than SSTbuoy03 and BT31 − BT32 to be small (−0.18 °C ± 0.22 °C), affecting the MCSST performance. The proposed bias correction algorithm uses a least-squares curve between SSTbuoy03 and SSTMODIS retrievals when BT31 − BT32 ≤ 0.5 °C (i.e., dry atmospheric conditions). The bias correction algorithm has significantly improved the SSTMODIS bias (RMSE) from 1.43 °C to −0.2 °C (1.60 °C to 0.58 °C) when applied to 22 cloud-free pixels of MODIS during January–March of 2015. [ABSTRACT FROM AUTHOR]

Real-time monitoring is a key tool for several automated features in distribution system. However, due to the limited number of real-time measurements, distribution system monitoring generally relies on load modeling procedures. This paper presents field results for a real-time monitoring tool that was implemented on a Brazilian distribution utility to provide load values for service restoration software. The implemented tool comprises two steps. The first step consists of preprocessing routines that provide the required information for a real-time load estimator that is executed in the second step. The field results provide evidence of the practical viability of the implemented real-time monitoring tool, demonstrating the tool overcomes some usual limitations of real-time load estimation procedures. More specifically, the implemented tool is able to handle multiple and different types of real-time measurements, treat real-time measurements on the feeder and not only in the head of the feeder, handle obviously bad data, and to satisfy the performance requirements on practically sized distribution systems. Besides proposing and confirming a real-time monitoring tool on a real distribution system, this paper shares valuable utility experience on providing new insights and the challenges faced for real-time monitoring projects. [ABSTRACT FROM PUBLISHER]

This paper aims at validating a code for the evaluation of lightning-induced overvoltages developed in the PSCAD-EMTDC environment using experimental results obtained on an experimental facility deployed at the University of São Paulo, Brazil that emulates the return stroke channel with a helical antenna. For this reason, suitable expressions for the helix electromagnetic fields are presented and conditions under which they can be approximated with the ones produced by the classical lightning channel model (i.e., a vertical antenna) are derived. Moreover, the analysis of the deviations between measurements and calculations is used as a tool to propose a channel vertical coordinate dependent function for the speed that guarantees the best fitting. The validation is done considering different line configurations, from a single line to a complex layout with one main feeder and many laterals and in the presence of non-linear elements, such as surge arresters. [ABSTRACT FROM AUTHOR]

In this paper, a simple algorithm is proposed to perform the nowcasting of rainfall in the tropical region. The algorithm applies global positioning system-derived precipitable water vapor (PWV) values and its second derivative for the short-term prediction of rainfall. The proposed algorithm incorporates the seasonal dependency of PWV values for the prediction of a rain event in the coming 5 min based on the past 30 min of PWV data. This proposed algorithm is based on the statistical study of four-year PWV and rainfall data from a station in Singapore and is validated using two-year independent data for the same station. The results show that the algorithm can achieve an average true detection rate and a false alarm rate of 87.7% and 38.6%, respectively. To analyze the applicability of the proposed algorithm, further validations are done using one-year data from one independent station from Singapore and two-year data from one station from Brazil. It is shown that the proposed algorithm performs well for both the independent stations. For the station from Brazil, the average true detection and false alarm rates are around 84.7% and 37%, respectively. All these observations suggest that the proposed algorithm is reliable and works well with a good detection rate. [ABSTRACT FROM AUTHOR]

Mine hoist systems play a vital role in gold ore transportation. They are the connection between the underground mine and the beneficiation plant. As a result, any hoist system interruption compromises the production. In this paper, it is proposed a mission critical analysis and design methodology for power converters in order to achieve proper reliability of the hoist drive system. Since the failure of power devices is responsible for a significant portion of the total downtime of power converters, a detailed study of the insulated gate bipolar transistor (IGBT) power modules lifetime is carried out. The three level neutral-point-clamped and Active Neutral Point Clamped (ANPC) IGBT-based topologies are considered for this application. The recently presented Fault-Tolerant (FT)-ANPC converter is proposed as a higher reliability solution leading to longer power modules and drive system lifetimes. All the studies are based on practical operating data from a 900-m deep shaft hoist system operating in a gold mine in southeastern Brazil. [ABSTRACT FROM AUTHOR]

This paper depicts an accident that happened in 2010 in a Brazilian chemical plant. A combination of different events, installations, and commissioning errors coupled with equipment failures involving the primary substation resulted in catastrophic failure. A single-phase failure of a 138-kV disconnect switch, during closing, initiated events and phenomena that resulted in a complete plant shutdown. This paper will walk the reader through the events, forensics analysis, and power system analysis that allowed the authors to identify what happened, how it happened, and what to do to prevent it from happening again. This paper will show how the anatomy of the problem, involving equipment failure, single-phase arcing, switching transients, overvoltage, capacitive coupling, transferred surge voltages, ungrounded system, transient overvoltage due to an arcing ground fault on an ungrounded system, insulation coordination, flashover, and lack of adequate surge protection, all of which resulted in a catastrophic failure of an arc resistant switchgear and a potentially serious arc flash incident. The research followed some steps that will be commented on here as well as the lessons learned. [ABSTRACT FROM AUTHOR]

The art of estimating future values of a random process, based upon previously observed or estimated values, is usually known as a priori estimation, prediction, or forecasting. Power system state estimation process can be enhanced if state/measurement forecasts are incorporated into it. Important research efforts have been made in this direction bringing a fresh perspective to the state estimation problem. This paper (Part I) presents a comprehensive survey of forecasting-aided state estimators. It gathers up-covering a period of three decades-research results on the main benefits achieved by state estimators with forecasting capability regarding: data redundancy, innovation analysis, observability, filtering, bad data, and network configuration and parameter error processing. Aspects of modeling, forecasting techniques, and computational effort are also addressed. The second of this two-paper series presents the results of the implementation of a forecasting-aided state estimator in the energy management system of the LIGHT Services of Electricity, a company which provides electric energy to Rio de Janeiro, Brazil. [ABSTRACT FROM AUTHOR]

This paper is the second part of a two-part paper addressing power system forecasting-aided state estimation. Part I presented a comprehensive survey on the subject, including future prospects. Part II is devoted to presentation and discussion of numerical results obtained with the implementation of a forecasting-aided state estimator in the energy management system of LIGHT Services of Electricity, which is company that supplies Rio de Janeiro, Brazil. This estimator is submitted to different situations, such as: normal operating conditions, presence of spurious measurements (including those which are critical), and occurrence of unpredictable sudden changes in the state of the LIGHT system. [ABSTRACT FROM AUTHOR]

This paper proposes a procedure and methodology for performance target setting related to continuity metrics in electricity distribution networks. This proposal deals with one of the key issues in the monopoly regulation, which is either the reduction of the information asymmetry among economic agents or the emulation of a competitive environment in industry segments usually considered as natural monopolies. This paper develops an approach toward standard definitions for Customer Average Interruption Duration Index (DEC) and Customer Average Interruption Frequency Index (FEC) based on inter-companies comparative analysis. This approach introduces productive efficiency concepts to the definition of network performance. In order to do so, the data envelopment analysis (DEA) technique, used for defining the efficiency frontier, was combined with the dynamic cluster technique, oriented toward models of identification of similar networks. A technique for comparative analysis was used for the definition of the network expected performance. Examples with the Brazilian electric systems are provided to clarify the methodology suggested by this paper. [ABSTRACT FROM AUTHOR]

This paper investigates the use of the constraint reactive implicit coupling (CRIC) method for the engine of a continuation power flow program. Full Newton continuation power flow methods are robust and accurate but are computationally expensive. Fast decoupled methods provide accurate results and require less computational time, but their performance worsens at heavy loading conditions, where the system active/reactive power decoupling characteristics are lost. This paper makes use of the CRIC method, which preserves the decoupled power flow solution structure but better models the active/reactive coupling. Effective stopping criteria are proposed for the continuation method, which helps to speed up computation. Such stopping criteria are also applied for tracing QV curves for some practical Brazilian power systems, with all operating limits considered. [ABSTRACT FROM AUTHOR]

The Brazilian petroleum and chemical industry had basically used medium-voltage (MV) power assemblies based on ANSI/NEMA for many years. However, in the last three decades, due to the Brazilian Standard Association orientation, the users and manufacturers have been changing their philosophies to the IEC culture. As there has been an everyday increase in the opportunity and also in the need of MV electrical power distribution in petrochemical facilities, there is the chance of adopting an MV switchgear or controlgear design based on ANSI or IEC standards, according to each plant specifications. Although the use and design of MV assemblies are based on the electric power system needs and characteristics, they are also a result of the current scenario and experience of a specific petrochemical facility. Since both ANSI and IEC universes have strong experience, knowledge, and huge safety concerns in electrical equipment design and application, the final choice is an interesting decision. It is important to keep in mind that the use of MV assemblies has to face technical and safety key issues as they are connected to an industrial power system, and both ANSI and IEC deal with such requirements very carefully: each one in its own way. This paper deals with impacting topics related to MV switchgear and controlgear such as the following: 1) ANSI and IEC requirements; 2) rated values and characteristics; 3) ancillary and power equipment application; 4) safety; and 5) ergonomics. [ABSTRACT FROM AUTHOR]

Today the knowledge of the ageing status of an electrical installation and its components is of fundamental interest for correctly inferring on the network economics. In Brazil, covered conductors must withstand an ageing test combining the stresses of heat, voltage to ground and corona. The observed failures indicate the necessity of complementary tests. In this paper Fourier transform infrared spectroscopy (FTIR), electron spin resonance (ESR), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), contact angle and scanning electron microscopy (SEM) measurements on artificially aged and unaged cross-linked polyethylene (XLPE) insulation of medium voltage covered conductors is reported. The ESR spectroscopy results show clear evidence of the presence of free radicals in all unaged and aged XLPE insulation cables suggesting inadequate manufacture and processing conditions. The FTIR showed the presence of carbonyl groups in both, unaged and aged XLPE insulation indicating that oxidation process occurred during the manufacturing process. The TGA analysis demonstrates that the decomposition temperature of XLPE insulation did not change significantly except for one of the manufactures. It was observed in DSC analysis that the ageing of the XLPE insulation causes a decrease in intensity and broadening of the peak corresponding to fusion heat, indicating the bond scission in the backbone of the XLPE. The contact angle measurements showed hydrophilic character for all unaged and aged XLPE insulation possibly due to some oxidation during cables manufacturing. After ageing the contact angle is about 23.1° and 52.4°, indicating a significant increasing in the hydrophilicity of the XLPE insulation. The increase in hydrophilicity of aged XLPE insulation appears to be due to the increase in oxygen functional groups and the results are consistent with the FTIR spectroscopy measurements. The defects observed in SEM analysis of unaged XLPE insulation indicate a nonuniform mechanical and thermal stresses during cables manufacturing. [ABSTRACT FROM PUBLISHER]

This paper describes a 10 V Josephson Voltage Standard (JVS) direct comparison between the National Institute of Standards and Technology (NIST) and the Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO) using automatic data acquisition. The results were in agreement to within 1.1 nV and the mean difference between the two JVSs at 10 V is 0.54 nV with a pooled combined standard uncertainty of 1.48 nV. Considering a recent JVS comparison between NIST and the Bureau International des Poids et Mesures (BIPM), the difference between INMETRO and the BIPM thus was found to be -0.26 nV with a standard uncertainty of 1.76 nV. INMETRO JVS improvements since the 2006 INMETRO-BIPM comparison are also described. [ABSTRACT FROM AUTHOR]

In this paper, we present the results of a hybrid fiber optic and RF-sensing technology for monitoring partial discharges on hydrogenerators, which can also be used for several other applications. The main advantages of the proposed system are passivity, flexibility, nonintrusive, inherently dielectric, and human and equipment risk-free. We describe the performance evaluation of the sensing system in laboratory and in field trial installed in a hydroelectric power station located in north of Brazil. [ABSTRACT FROM AUTHOR]

Schistosomiasis mansoni is a disease with social and behavioral characteristics. Snails of the Biomphalaria species, the disease's intermediate host, use water as a vehicle to infect man, the disease main host. In Brazil, six million people are infected. From 1995 to 2005, more than a million positive cases were reported, 27% of them in the state of Minas Gerais. The objective of this paper is to estimate the prevalence risk of schistosomiasis, terms of remote sensing, climate, socioeconomic, or neighborhood variables or a subset of them. We present two approaches modeling and classifying the infection risk: a global and a regional one, both of them using the aforementioned variables. In the first approach, a unique regression model was generated and used to estimate the disease risk for the entire state. In the second approach, the state was divided in four regions, and a model was generated for each of them. The first model obtained 47.2% of overall accuracy (AC) and the second achieved 62.4%, which were considered unsatisfactory. To improve these results, the concept of imprecise classification, defined in terms of the standard deviation of estimates and several reliability levels, is used for the generation of two imprecise classification maps. The AC for the imprecise classification was 83.8% for the global model and 91.9 % for the regional one, which were now considered acceptable. Particularly, regionalization has proven to be a good guideline to follow in future works involving geographical aspects and large data heterogeneity. [ABSTRACT FROM AUTHOR]

Among the most promising applications provided by interactive Digital Television Systems (iDTV) are the ones that enable TV-Sets to work as the central processing unit of a house. This is supported by the extending of iDTV common functionalities making use of its processing power not only to deal with image and audio but also to execute interactive software applications. This paper proposes a new infrastructure that allows the exchange of data from the iDTV to Home Automation devices, such as sensors, mobile devices, and so on. The integration process among the involved technologies as well as each element in the proposed infrastructure is described in details. This model is supported by Open Services Gateway initiative (OSGi), as a framework for networked devices, and the Brazilian reference middleware, Ginga. Thus it is possible to use devices services in OSGi-based Home Networks, through the Digital TV. in order to prove the model functionalities, we created validating scenarios of service management involving iDTV interaction with mobile phones and electronic sensor devices using WiFi and Bluetooth technologies. [ABSTRACT FROM AUTHOR]

The firm energy of generation plants is a critical component in some electricity markets. It is usually calculated by the regulator and sets a cap to the amount a plant can trade in capacity markets (or auctions), in order to avoid free-riding behaviors. Firm energy is a systemic property and, in case of hydro plants, a synergy is observed whenever a cooperative operation occurs, i.e., the firm energy of a system is greater than the sum of the individual plants. This immediately raises the question of how to divide the system's firm energy among the individual hydro plants. The objective of this work is to investigate the application of different allocation methods of firm energy rights among hydro plants using a game-theoretic framework. It is shown that there is not an optimal and unique approach to make this allocation. The paper investigates the advantages and disadvantages of different methods, such as marginal allocation, average production during the critical period, incremental allocation, finally recommending the Aumann-Shapley as the allocation method. This method is tested for the Brazilian power system, which has around 100 hydro plants. The results obtained are compared with the current allocation adopted by the electricity regulatory agency of Brazil. [ABSTRACT FROM AUTHOR]

This paper describes a study of the leakage current activity on glass-type insulators of high-voltage transmission lines over a three-month period. Three pairs of sensor systems were installed, one on a 500-ky field tower and the other two on 230-ky and 500-ky substation towers, all in the northeast region of Brasil. The locations were chosen due to their particular environment characteristics and the previous knowledge of pollution severity in these locations. The correlation of the leakage current attributes with in situ humidity records, insulator positions on the tower, and seasonality are discussed. [ABSTRACT FROM AUTHOR]

In this paper, an extended impedance-based fault-location formulation for generalized distribution systems is presented. The majority of distribution feeders are characterized by having several laterals, nonsymmetrical lines, highly unbalanced operation, and time-varying loads. These characteristics compromise traditional fault-location methods performance. The proposed method uses only local voltages and currents as input data. The current load profile is obtained through these measurements. The formulation considers load variation effects and different fault types. Results are obtained from numerical simulations by using a real distribution system from the Electrical Energy Distribution State Company of Rio Grande do Sul (CEEE-D), Southern Brazil. Comparative results show the technique robustness with respect to fault type and traditional fault-location problems, such as fault distance, resistance, inception angle, and load variation. The formulation was implemented as embedded software and is currently used at CEEE-D's distribution operation center. [ABSTRACT FROM AUTHOR]

In this paper the design of power system stabilizers for small-signal stability using phasor measurements is considered. An approach based on optimal control with structural constraints is proposed to design a two-level control structure. Time delays are included in the design. The method is combined with order reduction to ensure faster convergence of the design algorithm and to facilitate the choice of the weighting matrices for damping inter-area modes. The control scheme is discussed and modal analysis and time-domain simulations of two Brazilian equivalent systems are performed to assess the control performance. The robustness to loss of communication links, topological changes, and variations of time delay is evaluated. [ABSTRACT FROM AUTHOR]

In September 2000, an airborne synthetic aperture radar (SAR) mission acquired unprecedented full polarimetric P-band data over the Tapajós National Forest (Pará State), which is an area in the Brazilian Amazon which has been continuously monitored in the last three decades. Eight land use/cover classes were identified, namely, primary forest, regeneration older than 25 years, regeneration between 12 and 25 years, regeneration between 6 and 12 years, regeneration younger than six years, crops/pasture, bare soil, and floodplain (FP). The objective of this paper is to analyze the potential of full polarimetric P-band data in distinguishing different land use/cover classes with a minimum established Kappa value of 75%, using the latest development on SAR statistical characterization. The iterated conditional mode (ICM) contextual classifier was applied to amplitude, intensity images, biomass index, and some polarimetric parameters (entropy, α angle, and anisotropy) extracted from the polarimetric P-band data. As the accuracy obtained for eight classes was not acceptable, another two sets, with five and four classes, were formed by the combination of the previous ones. They were defined by confusion matrix analysis and by the graphical analysis of average backscatter values, entropy, α angle, and anisotropy images and by the H/α plans of the land use samples. The classification accuracy with four classes (three levels of biomass plus FP) was then considered acceptable with a Kappa value of 76.81%, using the ICM classification with the adequate bivariate distribution for the HV and VV channels. [ABSTRACT FROM AUTHOR]

Two methods have been largely studied and used in power systems reliability assessment: contingency enumeration and nonsequential Monte Carlo simulation. Both have their advantages and drawbacks. Contingency enumeration is conceptually simple and usually requires low computational effort. Conversely, Monte Carlo simulation is computationally harder, but much more versatile to model random aspects. This paper depicts some important practical aspects regarding the application of both methods, emphasizing how they can be used in a complementary way. The Brazilian interconnected electrical system is used to illustrate the risk assessment of an actual large scale power system, utilizing both techniques. [ABSTRACT FROM AUTHOR]

This paper gives a detailed account of the current practices used in Brazil for probabilistic reliability assessment of the national power grid, from the adequacy point of view. These procedures are utilized by the Brazilian independent electric system operator and were recently made mandatory by the National Electric Energy Regulatory Agency (ANEEL). [ABSTRACT FROM AUTHOR]

This paper proposes an optimization model to minimize the load curtailments necessary to restore the equilibrium of operating point with relaxation of restrictions. This model can be used for the operation planning of electrical power systems. The developed methodology minimizes the load cuts, limiting them to their importance and establishing different stages for them through the relaxation of the minimum limits of voltage and maximum limits of active power flows through the transformers. For instance, when an emergency occurs, if some operational limits are violated for a short period, fewer loads can be cut at a first stage than would be necessary if those violations would not be admitted. If the emergency does not cease, the remaining cuts necessary to recover the violations are made as a second stage of the strategy. On the other hand, if the contingency ceases, within this break, the system is recovered, and at this second stage, unnecessary cuts can be avoided, admitting only small breakings of operational restrictions. This methodology was tested at a system of 291 buses that is equivalent, in heavy load, to the electric network or the State of Parańa in Brazil. [ABSTRACT FROM AUTHOR]

Over the past decade, electric power systems have been restructured based on different models to introduce competition among market participants. Transmission open access for suppliers and customers is one of the most prevailing unbundling services. Usually, a connection tariff is established based on different market factors, including the actual usage of the transmission network. In Brazil, most vertically integrated companies owned by the federal and state governments were unbundled, and new transmission companies are being created. These companies make their assets available to the independent system operator, designated as Operador Nacional do Sistema Elétrico (ONS). One of the main objectives of ONS is to manage transmission services, over a certain voltage level, to ensure nondiscriminatory access to the grid. All transmission users, including regional distribution companies, pay wheeling transmission charges at each delivery or connection point with the major Brazilian network administrated by ONS. This paper presents a methodology for determining the optimal amount of transmission system usage (ATSU) that must be contracted by a regional distribution company, at each connection point. In the proposed approach, the maximum flow at each connection is represented as a random variable in order to obtain the distribution probability of the transmission charges as a function of the ATSU parameter. Besides providing the optimal amounts to be contracted, the proposed probabilistic methodology allows quantifying the risks of violation of each contract and estimating possible penalties. All methodology development steps are described and illustrated through numerical examples. An application to a typical Brazilian regional distribution company is also discussed. [ABSTRACT FROM AUTHOR]

This paper discusses a teaching experience obtained in the undergraduate course of Control Engineering at the Federal University of Santa Catarina (UFSC), Brazil. The course endeavors to introduce the students to the university and to the real world of engineering and to develop an understanding of basic engineering concepts and foster professional skills. By introducing practicing engineering to the course from day one, student motivation is increased, and the relationship between theoretical and practical aspects of engineering is demonstrated more clearly. This "hands-on approach" allows the student a greater insight into the life of an engineer. It strengthens a weakness found in established teaching methods, allowing the individual to embark on his or her engineering education with greater confidence in his or her ability as an engineer. [ABSTRACT FROM AUTHOR]

This paper presents the application of genetic algorithms in the optimization of an offset reflector antenna. The antenna shape is designed in order to obtain a uniform radiation pattern on the Brazilian territory. Modified genetic operators are proposed with the aim to increase the efficiency of the real coded genetic algorithms used lien. [ABSTRACT FROM AUTHOR]

In this paper, the optimal active power dispatch is formulated as a network flow optimization model and solved by interior point methods. The primal-dual and predictor-corrector versions of such interior point methods are developed and the resulting matrix structure is explored. This structure leads to very fast iterations since it is possible to reduce the linear system either to the number of buses or to the number of independent loops. Either matrix is invariant and can be factored offline. As a consequence of such matrix manipulations, a linear system which changes at each iteration has to be solved; its size, however, reduces to the number of generating units. These methods were applied to IEEE and Brazilian power systems and the numerical results were obtained using a C implementation. Both interior point methods proved to be robust and achieved fast convergence in all instances tested. [ABSTRACT FROM AUTHOR]

Free to air television is still an important tool to provide information and communication in many countries. Therefore, the universal access to the television system is very important. This paper presents a set of Digital Television accessible remote control devices designed for the Brazilian Digital Television. A research was conducted, interviewing people with disabilities in Brazil. Three remote control models were proposed, consolidating the main identified requirements, being accessible for a diverse group of impairments. [ABSTRACT FROM PUBLISHER]

GINGA-Nested Context Language (GINGANCL) is a subsystem of GINGA, the standard for the Brazilian mobile broadcasting service, and it specifies the mechanisms and services used to enable various interactive data services. The integral part of GINGA-NCL is the NCL declarative language that provides non-invasive control of a multimedia presentation in time and space, as well as user interaction. In particular, one of its core competitive advantages over other existing technologies, such as Broadcast Markup Language (BML) and Open Mobile Alliance-Rich Media Environment (OMA-RME), is that it is substantially light-weight. Therefore, in this paper, we introduce an implementation of a GINGANCL receiver for mobile handsets. The proposed solution supports full feature GINGA-NCL sets, including XHTML and ECMAScript1. [ABSTRACT FROM AUTHOR]

Information about several papers discussed at the Institute of Electrical and Electronics Engineers/International Federation for Information Processing (IEEE/IFIP) Network Operations and Management Symposium held at Salvador da Bahia, Brazil from April 7-11, 2008 is presented. It focused on the management of information technology (IT) world. Several speakers discussed how to manage networks and services, spectrum management issues, and the terrestrial digital television system.

The article profiles Nelson Fonseca, candidate for member-at-large of the Institute of Electrical & Electronics Engineers Inc. (IEEE) Communications Society. Fonseca received his doctorate degree in computer engineering from the University of Southern California in 1994. He is an associate professor at the State University of Campinas in Brazil and he has supervised almost 30 graduate students and has published almost 150 refereed papers. He used to be the director of the Online Services on the Board of Governors from 2002-2003 and is the chairman of the Multimedia Communications TC. Among his position statement notes that he will form channels to motivate members for the increase of their participation in the society.