Search results for: power market equilibrium model
Commenced in January 2007
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Edition: International
Paper Count: 24499

Search results for: power market equilibrium model

23329 Experimental and Numerical Analysis of Built-In Thermoelectric Generator Modules with Elliptical Pin-Fin Heat Sink

Authors: J. Y Jang, C. Y. Tseng

Abstract:

A three-dimensional numerical model of thermoelectric generator (TEG) modules attached to a large chimney plate is proposed and solved numerically using a control volume based finite difference formulation. The TEG module consists of a thermoelectric generator, an elliptical pin-fin heat sink, and a cold plate for water cooling. In the chimney, the temperature of flue gases is 450-650K. Therefore, the effects of convection and radiation heat transfer are considered. Although the TEG hot-side temperature and thus the electric power output can be increased by inserting an elliptical pin-fin heat sink into the chimney tunnel to increase the heat transfer area, the pin fin heat sink would cause extra pumping power at the same time. The main purpose of this study is to analyze the effects of geometrical parameters on the electric power output and chimney pressure drop characteristics. In addition, the effects of different operating conditions, including various inlet velocities (Vin = 1, 3, 5 m/s) and inlet temperatures (Tgas = 450, 550, 650K) are discussed in detail. The predicted numerical data for the power vs. current (P-I) curve are in good agreement (within 11%) with the experimental data.

Keywords: thermoelectric generator, waste heat recovery, pin-fin heat sink, experimental and numerical analysis

Procedia PDF Downloads 381
23328 A Method of Effective Planning and Control of Industrial Facility Energy Consumption

Authors: Aleksandra Aleksandrovna Filimonova, Lev Sergeevich Kazarinov, Tatyana Aleksandrovna Barbasova

Abstract:

A method of effective planning and control of industrial facility energy consumption is offered. The method allows to optimally arrange the management and full control of complex production facilities in accordance with the criteria of minimal technical and economic losses at the forecasting control. The method is based on the optimal construction of the power efficiency characteristics with the prescribed accuracy. The problem of optimal designing of the forecasting model is solved on the basis of three criteria: maximizing the weighted sum of the points of forecasting with the prescribed accuracy; the solving of the problem by the standard principles at the incomplete statistic data on the basis of minimization of the regularized function; minimizing the technical and economic losses due to the forecasting errors.

Keywords: energy consumption, energy efficiency, energy management system, forecasting model, power efficiency characteristics

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23327 Inter-Area Oscillation Monitoring in Maghrebian Power Grid Using Phasor Measurement Unit

Authors: M. Tsebia, H. Bentarzi

Abstract:

In the inter-connected power systems, a phenomenon called inter-area oscillation may be caused by several defects. In this paper, a study of the Maghreb countries inter-area power networks oscillation has been investigated. The inter-area oscillation monitoring can be enhanced by integrating Phasor Measurement Unit (PMU) technology installed in different places. The data provided by PMU and recorded by PDC will be used for the monitoring, analysis, and control purposes. The proposed approach has been validated by simulation using MATLAB/Simulink.

Keywords: PMU, inter-area oscillation, Maghrebian power system, Simulink

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23326 The Usage of Bridge Estimator for Hegy Seasonal Unit Root Tests

Authors: Huseyin Guler, Cigdem Kosar

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The aim of this study is to propose Bridge estimator for seasonal unit root tests. Seasonality is an important factor for many economic time series. Some variables may contain seasonal patterns and forecasts that ignore important seasonal patterns have a high variance. Therefore, it is very important to eliminate seasonality for seasonal macroeconomic data. There are some methods to eliminate the impacts of seasonality in time series. One of them is filtering the data. However, this method leads to undesired consequences in unit root tests, especially if the data is generated by a stochastic seasonal process. Another method to eliminate seasonality is using seasonal dummy variables. Some seasonal patterns may result from stationary seasonal processes, which are modelled using seasonal dummies but if there is a varying and changing seasonal pattern over time, so the seasonal process is non-stationary, deterministic seasonal dummies are inadequate to capture the seasonal process. It is not suitable to use seasonal dummies for modeling such seasonally nonstationary series. Instead of that, it is necessary to take seasonal difference if there are seasonal unit roots in the series. Different alternative methods are proposed in the literature to test seasonal unit roots, such as Dickey, Hazsa, Fuller (DHF) and Hylleberg, Engle, Granger, Yoo (HEGY) tests. HEGY test can be also used to test the seasonal unit root in different frequencies (monthly, quarterly, and semiannual). Another issue in unit root tests is the lag selection. Lagged dependent variables are added to the model in seasonal unit root tests as in the unit root tests to overcome the autocorrelation problem. In this case, it is necessary to choose the lag length and determine any deterministic components (i.e., a constant and trend) first, and then use the proper model to test for seasonal unit roots. However, this two-step procedure might lead size distortions and lack of power in seasonal unit root tests. Recent studies show that Bridge estimators are good in selecting optimal lag length while differentiating nonstationary versus stationary models for nonseasonal data. The advantage of this estimator is the elimination of the two-step nature of conventional unit root tests and this leads a gain in size and power. In this paper, the Bridge estimator is proposed to test seasonal unit roots in a HEGY model. A Monte-Carlo experiment is done to determine the efficiency of this approach and compare the size and power of this method with HEGY test. Since Bridge estimator performs well in model selection, our approach may lead to some gain in terms of size and power over HEGY test.

Keywords: bridge estimators, HEGY test, model selection, seasonal unit root

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23325 A Neural Network Approach for an Automatic Detection and Localization of an Open Phase Circuit of a Five-Phase Induction Machine Used in a Drivetrain of an Electric Vehicle

Authors: Saad Chahba, Rabia Sehab, Ahmad Akrad, Cristina Morel

Abstract:

Nowadays, the electric machines used in urban electric vehicles are, in most cases, three-phase electric machines with or without a magnet in the rotor. Permanent Magnet Synchronous Machine (PMSM) and Induction Machine (IM) are the main components of drive trains of electric and hybrid vehicles. These machines have very good performance in healthy operation mode, but they are not redundant to ensure safety in faulty operation mode. Faced with the continued growth in the demand for electric vehicles in the automotive market, improving the reliability of electric vehicles is necessary over the lifecycle of the electric vehicle. Multiphase electric machines respond well to this constraint because, on the one hand, they have better robustness in the event of a breakdown (opening of a phase, opening of an arm of the power stage, intern-turn short circuit) and, on the other hand, better power density. In this work, a diagnosis approach using a neural network for an open circuit fault or more of a five-phase induction machine is developed. Validation on the simulator of the vehicle drivetrain, at reduced power, is carried out, creating one and more open circuit stator phases showing the efficiency and the reliability of the new approach to detect and to locate on-line one or more open phases of a five-induction machine.

Keywords: electric vehicle drivetrain, multiphase drives, induction machine, control, open circuit (OC) fault diagnosis, artificial neural network

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23324 The Effect of Taxes on Development: An Albanian Case

Authors: Mergleda Hodo

Abstract:

All national governments aim to achieve economic equilibrium to build sustainable welfare, political stability, and economic equilibrium. There are various instruments to stimulate economic development and growth and achieve macroeconomic objectives. After the collapse of the political and economic system in the 1990s, some countries faced the complex challenge of economic development. This study aims to determine, based on empirical research, whether and to what extent tax revenue has an impact on the economic development of Albania. Furthermore, it gives an overview of the ways in which high tax burdens on the western Balkan countries have negatively affected foreign investment and reduced economic growth. This analysis is important for these selected countries, as the financial system has changed significantly over the years and has been affected significantly by a period of economic transition. The analysis is performed based on secondary data possessed by the World Bank and the central bank of each participating country between 2005 and 2018. The research findings indicate that tax policy affects, to a significant extent, the economic development of Albania. An efficient tax system is when individuals are willing to pay tax liability which will help in improving the economic well-being of a country.

Keywords: tax, development, economic growth, tax revenue

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23323 Design of Direct Power Controller for a High Power Neutral Point Clamped Converter Using Real-Time Simulator

Authors: Amin Zabihinejad, Philippe Viarouge

Abstract:

In this paper, a direct power control (DPC) strategies have been investigated in order to control a high power AC/DC converter with time variable load. This converter is composed of a three level three phase neutral point clamped (NPC) converter as rectifier and an H-bridge four quadrant current control converter. In the high power application, controller not only must adjust the desired outputs but also decrease the level of distortions which are injected to the network from the converter. Regarding this reason and nonlinearity of the power electronic converter, the conventional controllers cannot achieve appropriate responses. In this research, the precise mathematical analysis has been employed to design the appropriate controller in order to control the time variable load. A DPC controller has been proposed and simulated using Matlab/Simulink. In order to verify the simulation result, a real-time simulator- OPAL-RT- has been employed. In this paper, the dynamic response and stability of the high power NPC with variable load has been investigated and compared with conventional types using a real-time simulator. The results proved that the DPC controller is more stable and has more precise outputs in comparison with the conventional controller.

Keywords: direct power control, three level rectifier, real time simulator, high power application

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23322 The Impact of Insider Trading on Open Market Share Repurchase: A Study in Indian Context

Authors: Sarthak Kumar Jena, Chandra Sekhar Mishra, Prabina Rajib

Abstract:

Purpose: This paper aims to derive undervaluation signal from the insiders trading of Indian companies where the ownership is complex and concentrated, investors protection is weak, and the insider rules and regulations are not stringent like developed country. This study examines the relationship between insider trading with short term and long term abnormal return. The study also examines the relationship between insider trading and the actual share repurchase by the firm. Methodology: A sample of 78 companies over the period 2008-2013 are analyzed in the study due to not availability of insider data in Indian context. For preliminary analysis T-test and Wilcoxon rank sum test is used to find the difference between the insider trading before and after the share repurchase announcement. Tobit model is used to find out whether insider trading influence shares repurchase decisions or not. Return on the basis of market model and buy hold are calculated in the previous year and the following year of share repurchase announcement. Findings: The paper finds that insider trading around share repurchase is more than control firms and there is positive and significant difference in insider buying between the previous year of share buyback announcement and the following year of buyback announcement. Insider buying before share repurchase announcement has a positive influence on share repurchase decisions. We find insider buying has a positive and significant relationship with announcement return, whereas insider selling has a negative significant relationship with announcement return. Actual share repurchase and program completion also depend on insider trading before share repurchase. Research limitation: The study is constrained by the small sample size, so the results should be viewed by keeping this limitation in mind. Originality: The paper is to our best knowledge the first study based on Indian context to extend the insider trading literature to share repurchase event and examine insider trading to find out undervaluation signal associated with insider buying.

Keywords: insider trading, buyback, open market share repurchase, signalling

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23321 Ultrasound-Mediated Separation of Ethanol, Methanol, and Butanol from Their Aqueous Solutions

Authors: Ozan Kahraman, Hao Feng

Abstract:

Ultrasonic atomization (UA) is a useful technique for producing a liquid spray for various processes, such as spray drying. Ultrasound generates small droplets (a few microns in diameter) by disintegration of the liquid via cavitation and/or capillary waves, with low range velocity and narrow droplet size distribution. In recent years, UA has been investigated as an alternative for enabling or enhancing ultrasound-mediated unit operations, such as evaporation, separation, and purification. The previous studies on the UA separation of a solvent from a bulk solution were limited to ethanol-water systems. More investigations into ultrasound-mediated separation for other liquid systems are needed to elucidate the separation mechanism. This study was undertaken to investigate the effects of the operational parameters on the ultrasound-mediated separation of three miscible liquid pairs: ethanol-, methanol-, and butanol-water. A 2.4 MHz ultrasonic mister with a diameter of 18 mm and rating power of 24 W was installed on the bottom of a custom-designed cylindrical separation unit. Air was supplied to the unit (3 to 4 L/min.) as a carrier gas to collect the mist. The effects of the initial alcohol concentration, viscosity, and temperature (10, 30 and 50°C) on the atomization rates were evaluated. The alcohol concentration in the collected mist was measured with high performance liquid chromatography and a refractometer. The viscosity of the solutions was determined using a Brookfield digital viscometer. The alcohol concentration of the atomized mist was dependent on the feed concentration, feed rate, viscosity, and temperature. Increasing the temperature of the alcohol-water mixtures from 10 to 50°C increased the vapor pressure of both the alcohols and water, resulting in an increase in the atomization rates but a decrease in the separation efficiency. The alcohol concentration in the mist was higher than that of the alcohol-water equilibrium at all three temperatures. More importantly, for ethanol, the ethanol concentration in the mist went beyond the azeotropic point, which cannot be achieved by conventional distillation. Ultrasound-mediated separation is a promising non-equilibrium method for separating and purifying alcohols, which may result in significant energy reductions and process intensification.

Keywords: azeotropic mixtures, distillation, evaporation, purification, seperation, ultrasonic atomization

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23320 A Comparison of Biosorption of Radionuclides Tl-201 on Different Biosorbents and Their Empirical Modelling

Authors: Sinan Yapici, Hayrettin Eroglu

Abstract:

The discharge of the aqueous radionuclides wastes used for the diagnoses of diseases and treatments of patients in nuclear medicine can cause fatal health problems when the radionuclides and its stable daughter component mix with underground water. Tl-201, which is one of the radionuclides commonly used in the nuclear medicine, is a toxic substance and is converted to its stable daughter component Hg-201, which is also a poisonous heavy metal: Tl201 → Hg201 + Gamma Ray [135-167 Kev (12%)] + X Ray [69-83 Kev (88%)]; t1/2 = 73,1 h. The purpose of the present work was to remove Tl-201 radionuclides from aqueous solution by biosorption on the solid bio wastes of food and cosmetic industry as bio sorbents of prina from an olive oil plant, rose residue from a rose oil plant and tea residue from a tea plant, and to make a comparison of the biosorption efficiencies. The effects of the biosorption temperature, initial pH of the aqueous solution, bio sorbent dose, particle size and stirring speed on the biosorption yield were investigated in a batch process. It was observed that the biosorption is a rapid process with an equilibrium time less than 10 minutes for all the bio sorbents. The efficiencies were found to be close to each other and measured maximum efficiencies were 93,30 percent for rose residue, 94,1 for prina and 98,4 for tea residue. In a temperature range of 283 and 313 K, the adsorption decreased with increasing temperature almost in a similar way. In a pH range of 2-10, increasing pH enhanced biosorption efficiency up to pH=7 and then the efficiency remained constant in a similar path for all the biosorbents. Increasing stirring speed from 360 to 720 rpm enhanced slightly the biosorption efficiency almost at the same ratio for all bio sorbents. Increasing particle size decreased the efficiency for all biosorbent; however the most negatively effected biosorbent was prina with a decrease in biosorption efficiency from about 84 percent to 40 with an increase in the nominal particle size 0,181 mm to 1,05 while the least effected one, tea residue, went down from about 97 percent to 87,5. The biosorption efficiencies of all the bio sorbents increased with increasing biosorbent dose in the range of 1,5 to 15,0 g/L in a similar manner. The fit of the experimental results to the adsorption isotherms proved that the biosorption process for all the bio sorbents can be represented best by Freundlich model. The kinetic analysis showed that all the processes fit very well to pseudo second order rate model. The thermodynamics calculations gave ∆G values between -8636 J mol-1 and -5378 for tea residue, -5313 and -3343 for rose residue, and -5701 and -3642 for prina with a ∆H values of -39516 J mol-1, -23660 and -26190, and ∆S values of -108.8 J mol-1 K-1, -64,0, -72,0 respectively, showing spontaneous and exothermic character of the processes. An empirical biosorption model in the following form was derived for each biosorbent as function of the parameters and time, taking into account the form of kinetic model, with regression coefficients over 0.9990 where At is biosorbtion efficiency at any time and Ae is the equilibrium efficiency, t is adsorption period as s, ko a constant, pH the initial acidity of biosorption medium, w the stirring speed as s-1, S the biosorbent dose as g L-1, D the particle size as m, and a, b, c, and e are the powers of the parameters, respectively, E a constant containing activation energy and T the temperature as K.

Keywords: radiation, diosorption, thallium, empirical modelling

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23319 Application of Support Vector Machines in Fault Detection and Diagnosis of Power Transmission Lines

Authors: I. A. Farhat, M. Bin Hasan

Abstract:

A developed approach for the protection of power transmission lines using Support Vector Machines (SVM) technique is presented. In this paper, the SVM technique is utilized for the classification and isolation of faults in power transmission lines. Accurate fault classification and location results are obtained for all possible types of short circuit faults. As in distance protection, the approach utilizes the voltage and current post-fault samples as inputs. The main advantage of the method introduced here is that the method could easily be extended to any power transmission line.

Keywords: fault detection, classification, diagnosis, power transmission line protection, support vector machines (SVM)

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23318 Belief-Based Games: An Appropriate Tool for Uncertain Strategic Situation

Authors: Saied Farham-Nia, Alireza Ghaffari-Hadigheh

Abstract:

Game theory is a mathematical tool to study the behaviors of a rational and strategic decision-makers, that analyze existing equilibrium in interest conflict situation and provides an appropriate mechanisms for cooperation between two or more player. Game theory is applicable for any strategic and interest conflict situation in politics, management and economics, sociology and etc. Real worlds’ decisions are usually made in the state of indeterminacy and the players often are lack of the information about the other players’ payoffs or even his own, which leads to the games in uncertain environments. When historical data for decision parameters distribution estimation is unavailable, we may have no choice but to use expertise belief degree, which represents the strength with that we believe the event will happen. To deal with belief degrees, we have use uncertainty theory which is introduced and developed by Liu based on normality, duality, subadditivity and product axioms to modeling personal belief degree. As we know, the personal belief degree heavily depends on the personal knowledge concerning the event and when personal knowledge changes, cause changes in the belief degree too. Uncertainty theory not only theoretically is self-consistent but also is the best among other theories for modeling belief degree on practical problem. In this attempt, we primarily reintroduced Expected Utility Function in uncertainty environment according to uncertainty theory axioms to extract payoffs. Then, we employed Nash Equilibrium to investigate the solutions. For more practical issues, Stackelberg leader-follower Game and Bertrand Game, as a benchmark models are discussed. Compared to existing articles in the similar topics, the game models and solution concepts introduced in this article can be a framework for problems in an uncertain competitive situation based on experienced expert’s belief degree.

Keywords: game theory, uncertainty theory, belief degree, uncertain expected value, Nash equilibrium

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23317 Piezoelectric Approach on Harvesting Acoustic Energy

Authors: Khin Fai Chen, Jee-Hou Ho, Eng Hwa Yap

Abstract:

An acoustic micro-energy harvester (AMEH) is developed to convert wasted acoustical energy into useful electrical energy. AMEH is mathematically modeled using lumped element modelling (LEM) and Euler-Bernoulli beam (EBB) modelling. An experiment is designed to validate the mathematical model and assess the feasibility of AMEH. Comparison of theoretical and experimental data on critical parameter value such as Mm, Cms, dm and Ceb showed the variances are within 1% to 6%, which is reasonably acceptable. Hence, AMEH mathematical model is validated. Then, AMEH undergoes bandwidth tuning for performance optimization for further experimental work. The AMEH successfully produces 0.9 V⁄(m⁄s^2) and 1.79 μW⁄(m^2⁄s^4) at 60Hz and 400kΩ resistive load which only show variances about 7% compared to theoretical data. By integrating a capacitive load of 200µF, the discharge cycle time of AMEH is 1.8s and the usable energy bandwidth is available as low as 0.25g. At 1g and 60Hz resonance frequency, the averaged power output is about 2.2mW which fulfilled a range of wireless sensors and communication peripherals power requirements. Finally, the design for AMEH is assessed, validated and deemed as a feasible design.

Keywords: piezoelectric, acoustic, energy harvester

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23316 Impact of Brexit on the Structure of the European Insurance Market: A Solvency and Financial Condition Report Content Analysis of UK Insurance Companies

Authors: Antonia Müller, Svend Reuse

Abstract:

The Brexit referendum in June 2016 led to different publications analysing potential consequences for European and British insurance companies under the European Passport. This study addresses a research gap, regarding the measures taken by insurance companies based in the United Kingdom and thus on structural changes to the European insurance market by an innovative structured Solvency and Financial Condition Report content analysis. In scope are all insurance companies based in the United Kingdom, that fall under the Solvency II supervisory regime. The results show that the majority of British Solvency II insurance companies in scope, conducting cross-border business to the European Union, have applied and reported measures to be able to continue operating this cross-border business after Brexit. In addition, the study shows that 34 new insurance companies based in the European Union were established as a result of Brexit, indicating structural changes to the European insurance market.

Keywords: brexit, europe, insurance market, solvency and financial condition repot, structural changes

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23315 Molecular Characterization of Ardi Goat Assisted by Microsatellite Markers

Authors: M. F. Elzarei, A. M. Alseaf

Abstract:

Hundred uncorrelated animal and thirty six markers were used in this study to study the molecular characterization of Saudi native Ardi goat (BM18189, ILSTS030, INRA005, OarFCB48, BM2113, ILSTS033, INRA023, RM088, CSRD247, ILSTS034, INRA063, SRCRSP1, ILSTS002, ILSTS044, INRA172, SRCRSP5, ILSTS005, ILSTS049, MAF70, SRCRSP8, ILSTS011, ILSTS058, OarAE54, SRCRSP9, ILSTS019, ILSTS059, OARCP34, TGLA53, ILSTS022, ILSTS082, OARE129, TGLA73, ILSTS029, ILSTS087, OARE193, and RM004). Ardi goat showed high variability. The mean number of alleles per locus ranged from 5 in SRCRSP1 locus to 13.5 in CSRD247 locus. Gene diversities varied within a wide range, from 0.53 in ILSTS002 locus to 0.86 in RM088 locus. Hardy-Weinberg equilibrium was tested in order to evaluate the significance of inbreeding occurring in each locus in Ardi population. Only SRCRSP9, INRA005, ILSTS030 loci showed significance in this way.

Keywords: molecular characterization, microsatellite markers, Ardi goats, Hardy-Weinberg equilibrium

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23314 Influences of Market Orientation and Supply Chain Management on Competitive Capability in Case of Automotive Parts Industry

Authors: Nattapong Techarattanased

Abstract:

The objectives of this research were to study the influence of market orientation and supply chain management on competitive capability in case of the automotive parts industry in Thailand. This study employed by survey research and questionnaire was used to collect the data from 400 entrepreneurs in the automotive parts industry in Thailand. The descriptive statistics and multiple regression analysis were used to analyze data. The results revealed that the overall dimensions of marketing orientation, namely, responsiveness, intelligence generation, and intelligence dissemination were rated at the high level. As well, the overall dimensions of supply chain management, namely, collaboration, communication, trust, and commitment were also rated at the high level. Furthermore, the hypothesis testing results showed that supply chain management and market orientation affected competitive capability of the automotive parts industry in Thailand which these two variables could be combined to predict competitive capability of the automotive parts industry in Thailand by 31.5 percent.

Keywords: automotive parts industry, competitive capability, market orientation, supply chain management

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23313 Nigeria Energy Security: The Role of Solar Batteries

Authors: Ihugba Okezie A., Oguzie Emeka E.

Abstract:

Nigeria's renewable energy market is expanding due to increased environmental awareness, supportive government policies, and the need for energy diversification. This paper examines the role of solar batteries in enhancing Nigeria's energy security. With growing energy demands and frequent power outages, integrating solar batteries presents a viable solution to stabilize the energy supply. The study investigates the current state of solar battery technology in Nigeria, its economic and environmental benefits, and the challenges to implementation. Through a literature review, case studies, and stakeholder interviews, the paper provides a comprehensive analysis of solar batteries' contribution to a resilient energy future. Key players include Engie SA, TotalEnergies SE, Starsight Energy, Enel SpA, and North-South Power Co. Ltd. Challenges include high upfront costs, inadequate policies, weak infrastructure, and security risks. The paper recommends that the government should strengthen policies and incentives to encourage investments through tax breaks, subsidies, and financial incentives.

Keywords: renewable energy, solar batteries, energy security, Nigeria’s electricity generation, job creation

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23312 Reduced Power Consumption by Randomization for DSI3

Authors: David Levy

Abstract:

The newly released Distributed System Interface 3 (DSI3) Bus Standard specification defines 3 modulation levels from which 16 valid symbols are coded. This structure creates power consumption variations depending on the transmitted data of a factor of more than 2 between minimum and maximum. The power generation unit has to consider therefore the worst case maximum consumption all the time and be built accordingly. This paper proposes a method to reduce both the average current consumption and worst case current consumption. The transmitter randomizes the data using several pseudo-random sequences. It then estimates the energy consumption of the generated frames and selects to transmit the one which consumes the least. The transmitter also prepends the index of the pseudo-random sequence, which is not randomized, to allow the receiver to recover the original data using the correct sequence. We show that in the case that the frame occupies most of the DSI3 synchronization period, we achieve average power consumption reduction by up to 13% and the worst case power consumption is reduced by 17.7%.

Keywords: DSI3, energy, power consumption, randomization

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23311 Optimal Power Exchange of Multi-Microgrids with Hierarchical Coordination

Authors: Beom-Ryeol Choi, Won-Poong Lee, Jin-Young Choi, Young-Hak Shin, Dong-Jun Won

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A Microgrid (MG) has a major role in power system. There are numerous benefits, such as ability to reduce environmental impact and enhance the reliability of a power system. Hence, Multi-MG (MMG) consisted of multiple MGs is being studied intensively. This paper proposes the optimal power exchange of MMG with hierarchical coordination. The whole system architecture consists of two layers: 1) upper layer including MG of MG Center (MoMC) which is in charge of the overall management and coordination and 2) lower layer comprised of several Microgrid-Energy Management Systems (MG-EMSs) which make a decision for own schedule. In order to accomplish the optimal power exchange, the proposed coordination algorithm is applied to MMG system. The objective of this process is to achieve optimal operation for improving economics under the grid-connected operation. The simulation results show how the output of each MG can be changed through coordination algorithm.

Keywords: microgrids, multi-microgrids, power exchange, hierarchical coordination

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23310 Bringing Feminist Critical Pedagogy to the ESP Higher Education Classes: Feasibility and Challenges

Authors: Samira Essabari

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What, unfortunately, governs the Moroccan educational philosophy and policy today is a concerning neoliberal discourse with its obsession with market logics and individualism. Critical education has been advocated to resist the neoliberal hegemony since it holds the promise to reclaim the social function of education. Significantly, the mounting forms of sexism and discrimination against women combined with hegemonic educational practices are jeopardizing the social function of teaching and learning, hence the relevance of feminist critical pedagogy. A substantial body of research worldwide has explored the ways in which feminist pedagogy can develop feminist consciousness and examine power relations in different educational contexts. In Morocco, however, the feasibility of feminist pedagogy has not been researched despite the overwhelming interest in gender issues in different educational settings. The research on critical pedagogies in Morocco remains very promising. Yet, most studies were conducted in contexts which are already engaged with issues of theory, discourse, and discourse analysis. The field of ESP ( English for Specific Purposes) is pragmatic by nature, and priority in research has been given to questions that adhere to the mainstream concerns of need analysis and study skills and ignore issues of power, gender power relations, and intersectional forms of oppression. To address these gaps in the existing literature, this participatory action research seeks to investigate the feasibility of Feminist pedagogy in ESP higher education and how it can foster feminist critical consciousness among ESP students without compromising their language learning needs. The findings of this research will contribute to research on critical applied linguistics and critical ESP more specifically and add to the practice of critical pedagogies in Moroccan higher education by providing in-depth insights into the enablers and barriers to the implementation of feminist critical pedagogy, which is still feeling its way into the educational scene in Morocco.

Keywords: feminist pedagogy, critical pedagogy, power relations, gender, ESP, intersectionality

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23309 Detection of Voltage Sag and Voltage Swell in Power Quality Using Wavelet Transforms

Authors: Nor Asrina Binti Ramlee

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Voltage sag, voltage swell, high-frequency noise and voltage transients are kinds of disturbances in power quality. They are also known as power quality events. Equipment used in the industry nowadays has become more sensitive to these events with the increasing complexity of equipment. This leads to the importance of distributing clean power quality to the consumer. To provide better service, the best analysis on power quality is very vital. Thus, this paper presents the events detection focusing on voltage sag and swell. The method is developed by applying time domain signal analysis using wavelet transform approach in MATLAB. Four types of mother wavelet namely Haar, Dmey, Daubechies, and Symlet are used to detect the events. This project analyzed real interrupted signal obtained from 22 kV transmission line in Skudai, Johor Bahru, Malaysia. The signals will be decomposed through the wavelet mothers. The best mother is the one that is capable to detect the time location of the event accurately.

Keywords: power quality, voltage sag, voltage swell, wavelet transform

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23308 Analysis of Lift Force in Hydrodynamic Transport of a Finite Sized Particle in Inertial Microfluidics with a Rectangular Microchannel

Authors: Xinghui Wu, Chun Yang

Abstract:

Inertial microfluidics is a competitive fluidic method with applications in separation of particles, cells and bacteria. In contrast to traditional microfluidic devices with low Reynolds number, inertial microfluidics works in the intermediate Re number range which brings about several intriguing inertial effects on particle separation/focusing to meet the throughput requirement in the real-world. Geometric modifications to make channels become irregular shapes can leverage fluid inertia to create complex secondary flow for adjusting the particle equilibrium positions and thus enhance the separation resolution and throughput. Although inertial microfluidics has been extensively studied by experiments, our current understanding of its mechanisms is poor, making it extremely difficult to build rational-design guidelines for the particle focusing locations, especially for irregularly shaped microfluidic channels. Inertial particle microfluidics in irregularly shaped channels were investigated in our group. There are several fundamental issues that require us to address. One of them is about the balance between the inertial lift forces and the secondary drag forces. Also, it is critical to quantitatively describe the dependence of the life forces on particle-particle interactions in irregularly shaped channels, such as a rectangular one. To provide physical insights into the inertial microfluidics in channels of irregular shapes, in this work the immersed boundary-lattice Boltzmann method (IB-LBM) was introduced and validated to explore the transport characteristics and the underlying mechanisms of an inertial focusing single particle in a rectangular microchannel. The transport dynamics of a finitesized particle were investigated over wide ranges of Reynolds number (20 < Re < 500) and particle size. The results show that the inner equilibrium positions are more difficult to occur in the rectangular channel, which can be explained by the secondary flow caused by the presence of a finite-sized particle. Furthermore, force decoupling analysis was utilized to study the effect of each type of lift force on the inertia migration, and a theoretical model for the lateral lift force of a finite-sized particle in the rectangular channel was established. Such theoretical model can be used to provide theoretical guidance for the design and operation of inertial microfluidics.

Keywords: inertial microfluidics, particle focuse, life force, IB-LBM

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23307 Extreme Value Modelling of Ghana Stock Exchange Indices

Authors: Kwabena Asare, Ezekiel N. N. Nortey, Felix O. Mettle

Abstract:

Modelling of extreme events has always been of interest in fields such as hydrology and meteorology. However, after the recent global financial crises, appropriate models for modelling of such rare events leading to these crises have become quite essential in the finance and risk management fields. This paper models the extreme values of the Ghana Stock Exchange All-Shares indices (2000-2010) by applying the Extreme Value Theory to fit a model to the tails of the daily stock returns data. A conditional approach of the EVT was preferred and hence an ARMA-GARCH model was fitted to the data to correct for the effects of autocorrelation and conditional heteroscedastic terms present in the returns series, before EVT method was applied. The Peak Over Threshold (POT) approach of the EVT, which fits a Generalized Pareto Distribution (GPD) model to excesses above a certain selected threshold, was employed. Maximum likelihood estimates of the model parameters were obtained and the model’s goodness of fit was assessed graphically using Q-Q, P-P and density plots. The findings indicate that the GPD provides an adequate fit to the data of excesses. The size of the extreme daily Ghanaian stock market movements were then computed using the Value at Risk (VaR) and Expected Shortfall (ES) risk measures at some high quantiles, based on the fitted GPD model.

Keywords: extreme value theory, expected shortfall, generalized pareto distribution, peak over threshold, value at risk

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23306 Adaptive Control of Magnetorheological Damper Using Duffing-Like Model

Authors: Hung-Jiun Chi, Cheng-En Tsai, Jia-Ying Tu

Abstract:

Semi-active control of Magnetorheological (MR) dampers for vibration reduction of structural systems has received considerable attention in civil and earthquake engineering, because the effective stiffness and damping properties of MR fluid can change in a very short time in reaction to external loading, requiring only a low level of power. However, the inherent nonlinear dynamics of hysteresis raise challenges in the modeling and control processes. In order to control the MR damper, an innovative Duffing-like equation is proposed to approximate the hysteresis dynamics in a deterministic and systematic manner than previously has been possible. Then, the model-reference adaptive control technique based on the Duffing-like model and the Lyapunov method is discussed. Parameter identification work with experimental data is presented to show the effectiveness of the Duffing-like model. In addition, simulation results show that the resulting adaptive gains enable the MR damper force to track the desired response of the reference model satisfactorily, verifying the effectiveness of the proposed modeling and control techniques.

Keywords: magnetorheological damper, duffing equation, model-reference adaptive control, Lyapunov function, hysteresis

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23305 On the Impact of Oil Price Fluctuations on Stock Markets: A Multivariate Long-Memory GARCH Framework

Authors: Manel Youssef, Lotfi Belkacem

Abstract:

This paper employs multivariate long memory GARCH models to simultaneously estimate mean and conditional variance spillover effects between oil prices and different financial markets. Since different financial assets are traded based on these market sector returns, it’s important for financial market participants to understand the volatility transmission mechanism over time and across these series in order to make optimal portfolio allocation decisions. We examine weekly returns from January 1, 2003 to November 30, 2012 and find evidence of significant transmission of shocks and volatilities between oil prices and some of the examined financial markets. The findings support the idea of cross-market hedging and sharing of common information by investors.

Keywords: oil prices, stock indices returns, oil volatility, contagion, DCC-multivariate (FI) GARCH

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23304 PSS and SVC Controller Design by BFA to Enhance the Power System Stability

Authors: Saeid Jalilzadeh

Abstract:

Designing of PSS and SVC controller based on Bacterial Foraging Algorithm (BFA) to improve the stability of power system is proposed in this paper. Same controllers for PSS and SVC has been considered and Single machine infinite bus (SMIB) system with SVC located at the terminal of generator is used to evaluate the proposed controllers. BFA is used to optimize the coefficients of the controllers. Finally simulation for a special disturbance as an input power of generator with the proposed controllers in order to investigate the dynamic behavior of generator is done. The simulation results demonstrate that the system composed with optimized controllers has an outstanding operation in fast damping of oscillations of power system.

Keywords: PSS, SVC, SMIB, optimize controller

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23303 An Extended Basic Period and Power-of-Two Policy for Economic Lot-Size Batch-Shipment Scheduling Problem

Authors: Wen-Tsung Ho, Ku-Kuang Chang, Hsin-Yuan Chang

Abstract:

In this study, we consider an economic lot-size batch-shipment scheduling problem (ELBSP) with extended basic period (EBP) and power-of-two (PoT) policies. In this problem, the supplier using a single facility to manufacture multiple products and equally sized batches are then delivered by the supplier to buyers over an infinite planning horizon. Further, the extended basic period (EBP) and power-of-two (PoT) policy are utilized. Relaxing the production schedule converts the ELBSP to an economic lot-size batch-shipment problem (ELBP) with EBP and PoT policies, and a nonlinear integer programming model of the ELBP is constructed. Using the replenishment cycle division and recursive tightening methods, optimal solutions are then solved separately for each product. The sum of these optimal solutions is the lower bound of the ELBSP. A proposed heuristic method with polynomial complexity is then applied to figure out the near-optimal solutions of the ELBSP. Numerical example is presented to confirm the efficacy of the proposed method.

Keywords: economic lot-size scheduling problem, extended basic period, replenishment cycle division, recursive tightening, power-of-two

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23302 A Novel Microcontroller Based Islanding Protection of Distributed Generation Systems

Authors: Saeid Jalilzadeh, Majid Pakdel

Abstract:

The customer demand for better power quality and higher reliability has forced the power industry to use distributed generations (DGs) such as wind power and photo voltaic arrays. Islanding is a phenomenon occurs when a power grid becomes electrically isolated from the power system and the distribution system is energized by distributed generators. It is necessary to disconnect all distributed generators immediately after islanding occurrence. Therefore a DG system should have the capability to detect islanding phenomena. In this paper, a novel micro controller based relay for anti-islanding protection of a typical DG system is proposed. The simulation results using Proteus software verify the proper operation and effectiveness of the proposed protective relay.

Keywords: islanding, distributed generation (DG), protective relay, micro controller, proteus software

Procedia PDF Downloads 581
23301 The Strategic Engine Model: Redefined Strategy Structure, as per Market-and Resource-Based Theory Application, Tested in the Automotive Industry

Authors: Krassimir Todorov

Abstract:

The purpose of the paper is to redefine the levels of structure of corporate, business and functional strategies that were established over the past several decades, to a conceptual model, consisting of corporate, business and operations strategies, that are reinforced by functional strategies. We will propose a conceptual framework of different perspectives in the role of strategic operations as a separate strategic place and reposition the remaining functional strategies as supporting tools, existing at all three levels. The proposed model is called ‘the strategic engine’, since the mutual relationships of its ingredients are identical with main elements and working principle of the internal combustion engine. Based on theoretical essence, related to every strategic level, we will prove that the strategic engine model is useful for managers seeking to safeguard the competitive advantage of their companies. Each strategy level is researched through its basic elements. At the corporate level we examine the scope of firm’s product, the vertical and geographical coverage. At the business level, the point of interest is limited to the SWOT analysis’ basic elements. While at operations level, the key research issue relates to the scope of the following performance indicators: cost, quality, speed, flexibility and dependability. In this relationship, the paper provides a different view for the role of operations strategy within the overall strategy concept. We will prove that the theoretical essence of operations goes far beyond the scope of traditionally accepted business functions. Exploring the applications of Resource-based theory and Market-based theory within the strategic levels framework, we will prove that there is a logical consequence of the theoretical impact in corporate, business and operations strategy – at every strategic level, the validity of one theory is substituted to the level of the other. Practical application of the conceptual model is tested in automotive industry. Actually, the proposed theoretical concept is inspired by a leading global automotive group – Inchcape PLC, listed on the London Stock Exchange, and constituent of the FTSE 250 Index.

Keywords: business strategy, corporate strategy, functional strategies, operations strategy

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23300 AI/ML Atmospheric Parameters Retrieval Using the “Atmospheric Retrievals conditional Generative Adversarial Network (ARcGAN)”

Authors: Thomas Monahan, Nicolas Gorius, Thanh Nguyen

Abstract:

Exoplanet atmospheric parameters retrieval is a complex, computationally intensive, inverse modeling problem in which an exoplanet’s atmospheric composition is extracted from an observed spectrum. Traditional Bayesian sampling methods require extensive time and computation, involving algorithms that compare large numbers of known atmospheric models to the input spectral data. Runtimes are directly proportional to the number of parameters under consideration. These increased power and runtime requirements are difficult to accommodate in space missions where model size, speed, and power consumption are of particular importance. The use of traditional Bayesian sampling methods, therefore, compromise model complexity or sampling accuracy. The Atmospheric Retrievals conditional Generative Adversarial Network (ARcGAN) is a deep convolutional generative adversarial network that improves on the previous model’s speed and accuracy. We demonstrate the efficacy of artificial intelligence to quickly and reliably predict atmospheric parameters and present it as a viable alternative to slow and computationally heavy Bayesian methods. In addition to its broad applicability across instruments and planetary types, ARcGAN has been designed to function on low power application-specific integrated circuits. The application of edge computing to atmospheric retrievals allows for real or near-real-time quantification of atmospheric constituents at the instrument level. Additionally, edge computing provides both high-performance and power-efficient computing for AI applications, both of which are critical for space missions. With the edge computing chip implementation, ArcGAN serves as a strong basis for the development of a similar machine-learning algorithm to reduce the downlinked data volume from the Compact Ultraviolet to Visible Imaging Spectrometer (CUVIS) onboard the DAVINCI mission to Venus.

Keywords: deep learning, generative adversarial network, edge computing, atmospheric parameters retrieval

Procedia PDF Downloads 168