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Search Results: 1 - 10 of 50582 matches for " Y. Nagasaka "
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A Neural Network and Expert Systems Based Model for Measuring Business Effectiveness of Information Technology Investment  [PDF]
Mahmud Mavaahebi, Ken Nagasaka
American Journal of Industrial and Business Management (AJIBM) , 2013, DOI: 10.4236/ajibm.2013.32030
Abstract:

Today’s indispensable bound between Information Technology (IT) and Business bears heavy expectations on IT to enable firms achieve their strategic business goals and drive competitiveness [1] and revenue growth via offered Technology Solutions and Services. To assess achievement level associated with such expectations, mechanisms must exist for determining the relationship between Organization’s Technology investments and services provided by IT, enabling quantification of effectiveness. In spite of many methods and tools on the market for measuring the Return On Investment (ROI) [2], Net Present Values (NPV), etc., and various studies that have been conducted toward measuring IT’s Business effectiveness, the result has been mostly qualitative, speculative and hypothetical. A mechanism does not seem to exist for measuring [3] quantitatively the effectiveness of incurred technology investment in an organization by leveraging such concepts as Neural Nets or Fuzzy Logic. While Neural Network has been providing possibilities for solving problems in various fields such as Medicine, Engineering, Finance, Economics, etc., [4] its capabilities do not appear to have been explored adequately in the field of Information Technology. Hence, a research is being conducted to develop a Neural Nets/Expert Systems model that can identify within a firm the correlation between IT cost factors, IT services, percentage of utilized services by Business Functions and their associative technology costs inline with the percentage of contributions made by each Function toward achieving Business Objectives. Once developed, the model can calculate Yielded Unit Costs of IT Services and Business Objectives for comparison with their respective optimized unit costs to determine effectiveness and impact that Technology investment has caused on achieving Objectives during a given fiscal period. Neural Network’s modeling is used for developing patterns and quantifying correlations between various layers based on past experiences. Additionally, the model can more accurately forecast required Technology investment for an upcoming fiscal period.

Effect of Wind Generation System Rating on Transient Dynamic Performance of the Micro-Grid during Islanding Mode  [PDF]
Rashad M. Kamel, Aymen Chaouachi, Ken Nagasaka
Low Carbon Economy (LCE) , 2010, DOI: 10.4236/lce.2010.11005
Abstract: Recently, several types of distributed generations (DGs) are connected together and form a small power system called Micro Grid (MG). This paper developed a complete model which can simulate in details the transient dynamic perfor-mance of the MG during and subsequent to islanding process. All MG’s components are modeled in detail. The devel-oped model is used to investigate how the transient dynamic performance of the MG will affected by increasing the rating of wind generation system installed in the MG. Two cases are studied; the first case investigates the dynamic performance of the MG equipped with 10 kW fixed speed wind generation system. The second studied case indicates how the dynamic performance of the MG will be affected if the wind generation system rating increases to 30 kW. The results showed that increasing of wind generation rating on the MG causes more voltage drops and more frequency fluctuations due to the fluctuation of wind speed. Increasing voltage drops because wind turbine generator is a squirrel cage induction generator and absorbs more reactive power when the generated active power increases. The frequency fluctuations due to power fluctuations of wind turbine as results of wind speed variations. The results proved that when the MG equipped with large wind generation system, high amount of reactive power must be injected in the system to keep its stability. The developed model was built in Matlab® Simulink® environment.
Carbon Emissions Reduction and Power Losses Saving besides Voltage Profiles Improvement Using Micro Grids  [PDF]
Rashad M. Kamel, Aymen Chaouachi, Ken Nagasaka
Low Carbon Economy (LCE) , 2010, DOI: 10.4236/lce.2010.11001
Abstract: The objective of this paper is to evaluate the value of enhancement in voltage, amount of emission reduction and amount of power losses saving with using micro grids. The paper is divided in two parts, the first part evaluates the voltage improvement and power losses saving with micro (μ) sources (distributed generators like fuel cell, micro tur-bine, solar cell, wind turbine etc.). The obtained results indicate that using μ sources reduce voltage drop by about 3%, Also, it is found that using μ sources can reduce the power losses to more than one third of its value without using μ sources. The voltage at the buses near the μ sources location will suffer from small drop than the buses far from μ sources locations. The second part calculates amount of CO2, SO2, NOx and particulate matters emissions from main grid and from μ sources which forms micro grid. The results indicates that more penetration of μ sources in the power systems especially the renewable sources (solar and wind) will help in reducing or removing emission problems and solve the green house gas problems. Finally this paper proved with calculations that the micro grid can solve most of the problems which facing the conventional power system and keep the surrounding environment clean from pollution and the micro grid will be the future power system.
Design and Testing of Three Earthing Systems for Micro-Grid Protection during the Islanding Mode  [PDF]
Rashad M. Kamel, Aymen Chaouachi, Ken Nagasaka
Smart Grid and Renewable Energy (SGRE) , 2010, DOI: 10.4236/sgre.2010.13018
Abstract: This paper presents and tests three earthing systems (TT, TN and IT) for Micro-Grid (MG) protection against various fault types when the MG transferred to the islanding mode. The main contribution of this work is including the models of all micro sources which interfaced to the MG by power electronic inverters. Inverters in turns are provided with current limiters and this also included with the inverter models to exactly simulate the real situation in the MG during fault times. Results proved that the most suitable earthing system for MG protection during the islanding mode is the TN earthing system. That system leads to a suitable amount of fault current sufficient to activate over current pro-tection relays. With using TN earthing system, touch voltages at the faulted bus and all other consumer’s buses are less than the safety limited values during islanding mode. For the two others earthing systems (TT and IT), fault currents are small and nearly equal to the over load currents which make over current protection relay can not differentiate between fault currents and overload currents. All models of micro sources, earthing systems, inverters and control schemes are built using Matlab?/Simulink? environment.
Detailed Analysis of Micro-Grid Stability during Islanding Mode under Different Load Conditions  [PDF]
Rashad M. Kamel, A. Chaouachi, Ken Nagasaka
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.35059
Abstract: Today, several types of DGs are connected together and formed a small power system called micro-grid (MG). MG is connected to the primary distribution network and usually operates in normal connecting mode. When a severe fault occurs in the primary distribution network, then the MG will transfer to islanding mode. In this paper a complete model is developed to simulate the dynamic performance of the MG during and subsequent to islanding process. The model contains of a solid oxide fuel cell (SOFC), a single shaft micro turbine, a flywheel, two photovoltaic panels and a wind generator system. All these micro sources are con-nected to the MG through inverters except the wind generation system. The inverters are modeled with two control strategies. The first strategy is PQ control which the inverter will inject a certain active and reactive powers. This type of inverter is used to interface micro turbine, fuel cell and photovoltaic panels to the MG. The second strategy is Vf control. This model is used to interface flywheel will act as the reference bus (slack bus) for the MG when islanding occurs. Two cases are studied: the first case discusses the effect of islanding process on frequency, voltage and active power of all micro sources when the MG imports active and reactive power from the primary distribution network. The second studied case, also, shows the effect of islanding on the previous quantities particularly when the MG exports active and reactive power to the pri-mary distribution network. Results showed that the existence of storage device (flywheel) with appropriate control of its inverter can keep the frequency of the MG and the voltages of all buses within their limited levels. The developed model is built in Matlab® Simulink® environment.
Analysis of Transient Dynamic Response of Two Nearby Micro-Grids under Three Different Control Strategies  [PDF]
Rashad M. Kamel, Aymen Chaouachi, Ken Nagasaka
Low Carbon Economy (LCE) , 2010, DOI: 10.4236/lce.2010.12006
Abstract: The need of reducing CO2 emissions in electricity generation field for solving global warming problems have led to increase the interest in Micro-Grid (MG) especially the one which included renewable sources. MG normally operates in normal interconnected mode and connects with the main grid. When a large disturbance happens in main grid, MG transfer to islanding mode. This paper deals with connecting two nearby Micro-Grids to enhance transient dynamic response of the two MGs after isolated from the main grid. Three cases are investigated. The first case discussed the dynamic response of the two MGs when there is no tie line connection between the two MGs after islanding. Second case, studied the dynamic performance of the two Micro-Grids when there is a private line connects the two MGs after islanding from main grid, while the third case deals with two interconnected MGs (after islanding) and automatic generation control (AGC) applied upon each MG to return the frequency to its nominal value and control the tie line power to be with its scheduled value. Results proofed that when two nearby MGs are connected by private line after islanding from the main grid occurs, dynamic response of the two MGs improved well.
Comparison the Performances of Three Earthing Systems for Micro-Grid Protection during the Grid Connected Mode  [PDF]
Rashad Mohammedeen Kamel, Aymen Chaouachi, Ken Nagasaka
Smart Grid and Renewable Energy (SGRE) , 2011, DOI: 10.4236/sgre.2011.23024
Abstract: This paper presents, tests and compares three earthing systems (TT, TN and IT) for Micro-Grid (MG) protection against various fault types during the connected mode. The main contribution of this work is including the models of all the micro sources which interfaced to the MG by power electronic inverters. Inverters in turns are provided with current limiters and this also included in the inverter models to exactly simulate the real situation in the MG during fault times. Results proved that the most suitable earthing system for MG protection during the connecting mode is the TN earthing system. That system leads to a suitable amount of fault current sufficient to activate over current protection relays. With using TN system, Touch voltages at the faulted bus and all other consumer’s buses are less than the safety limited value if current limiter is included with the transformer of the main grid which connects MG. For the two others earthing systems (TT and IT), fault current is small and nearly equal to the over load current which make over current protection relay can not differentiate between fault current and overload current. All models of micro sources, earthing systems, inverters, main grid and control schemes are built using Matlab®/Simulink® environment.
An emergent framework of disaster risk governance towards innovating coping capability for reducing disaster risks in local communities
Saburo Ikeda,Toshinari Nagasaka
International Journal of Disaster Risk Science , 2011, DOI: 10.1007/s13753-011-0006-7
Abstract: An emergent framework of disaster risk governance is presented as an implementation strategy for integrated risk management that incorporates innovative local coping capabilities that reduce disaster vulnerability. This framework calls for enhancement of self-support and mutual-assistance through strengthening informal or social networking efforts in local communities, rather than depending on formal or institutional governmental-assistance. The framework is supported by a societal platform of disaster risk information, called DRIP, which the NIED (National Research Institute for Earth Science and Disaster Prevention, Japan) has developed since 2006 as a tool that promotes improved disaster risk governance. With the help of DRIP, residents, communities, and other stakeholders, linked horizontally or vertically with social networks, can (1) improve their awareness of disaster risks and management issues by sharing risk information as scientific expertise, experiential knowledge, and local/folk wisdom; (2) customize risk communication through analytic deliberation of risk information by employing risk-scenarios developed by residents themselves; (3) develop collaborative activities for informed decision-making that can fully utilize local resources to reorganize coping capability against disaster risks; and (4) disseminate the generated risk scenarios with action plans to other residents who have not participated in the risk communication process.
Assessment of Wind Energy Potential in Indonesia Using Weibull Distribution Function
Meita Rumbayan,Ken Nagasaka
International Journal of Electrical and Power Engineering , 2012, DOI: 10.3923/ijepe.2011.229.235
Abstract: The wind characteristic information will be useful in identifying prospective areas for wind-energy applications. The purposes of this study are to analyze the wind characteristic for selected locations in Indonesia based on available data. The wind characteristic for Bali, Balikpapan, Surabaya and Jayapura were analyzed based on the daily average wind speed which is available in National Oceanic and Atmospheric Administration (NOAA) website. The wind characteristics were analyzed using statistical analysis and the Weibull parameter as the Weibull distribution generally accepted methodology used to estimate the wind speed frequency distribution. Even though, wind characteristic analysis indicates low potential of wind energy in Indonesia, the result of this study can be useful information about wind research in Indonesia. Evaluation of the potential of wind energy resources in Indonesia need to be conducted as there is very limited research on the assessment of wind energy potential in Indonesia.
Demand and Price Forecasting by Artificial Neural Networks (ANNs) in a Deregulated Power Market
YanBin Xu,Ken Nagasaka
International Journal of Electrical and Power Engineering , 2012,
Abstract: In a deregulated electricity market, where the electricity is trading among power suppliers and retailers in the pool market. The demand and price forecasting become important and play an important role for the market participants. Accurate forecasting tools are essential for producers to maximize their profits, avowing profit losses over the misjudgment of future price movements and for consumers to maximize their utilities. This study proposes two step forecast model by the Artificial Neural Networks (ANNs) to forecast one hour ahead demand and price of electricity. A three-layer BP (Back-Propagation) model was designed to train the historical data, then it was tested to predict both demand and price of electricity. In this study, the data from Queensland electricity market of Australia is used and promising results were obtained.
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