The paper presents new MPPT algorithm for partial shading of series connected PV cells/modules. In the shaded condition, there is a problem of decrease in the total output power of the PV system. The proposed algorith...The paper presents new MPPT algorithm for partial shading of series connected PV cells/modules. In the shaded condition, there is a problem of decrease in the total output power of the PV system. The proposed algorithm aims to reduce this problem by active bypassing of the shaded cells. The algorithm senses the irradiance of each cell and performs calculation in order to decide if to actively bypass the shaded cell or not. Extensive simulation results proved that algorithm works and increases the output power under partial shading conditions. Furthermore, the algorithm becomes more efficient when the number of cells is increased.展开更多
The smart grid is a new generation of standard power distribution grid. The communication infrastructure is critical for the successful operation of the modern smart grids. The use of communication technologies ensure...The smart grid is a new generation of standard power distribution grid. The communication infrastructure is critical for the successful operation of the modern smart grids. The use of communication technologies ensures the reduction of energy consumption, optimal operation of the smart grid and coordination between all smart grids’ components from generation to the end users. This paper presents an overview of existing communication technologies such as ZigBee, WLAN, cellular communication, WiMAX, Power Line Communication (PLC), their implementation in smart grids, advantages and disadvantages. Moreover, the paper shows comparison of communication infrastructure between the legacy grid and the smart grid and smart grid communication standards. The paper also presents research challenges and future trends in communication systems for smart grid application.展开更多
Over the past 20 years,and with greater urgency since the H5N1 papers controversy(2012),dual-use research of concern(DURC)has been extensively debated by the scientific community,regulators,and the public at large.Man...Over the past 20 years,and with greater urgency since the H5N1 papers controversy(2012),dual-use research of concern(DURC)has been extensively debated by the scientific community,regulators,and the public at large.Many have raised the need to regulate DURC;however,despite the urgency of this issue,to date,only two countries have implemented specific regulations,United States and Israel(notably,China is in the final stages of creating a set of DURC-related regulations).In this paper,I have compared these policies as case studies that may benefit other countries.Therefore,the present study aimed to critically compare the DURC policies of the US and Israel and determine whether their different approaches provide a rigorous framework for the regulation of DURC.I have shown that in some aspects,they have adopted similar approaches;for example,allowing local committees to play a role in assessing the research.However,they differ in certain important aspects;for instance,the US policies have laid out a mechanism through which academic institutions and the government decide jointly on how to address risky studies,while the Israeli law places the authority solely in government hands.My aim in comparing the policies is twofold;first,to reveal the weaknesses and strengths of each policy,thereby aiding their improvement,and second,to provide those that are considering developing policies in this field an overview of what the current approaches look like,thereby enabling them to articulate their own approach while taking into account the experience gained by the US and Israel.展开更多
文摘The paper presents new MPPT algorithm for partial shading of series connected PV cells/modules. In the shaded condition, there is a problem of decrease in the total output power of the PV system. The proposed algorithm aims to reduce this problem by active bypassing of the shaded cells. The algorithm senses the irradiance of each cell and performs calculation in order to decide if to actively bypass the shaded cell or not. Extensive simulation results proved that algorithm works and increases the output power under partial shading conditions. Furthermore, the algorithm becomes more efficient when the number of cells is increased.
文摘The smart grid is a new generation of standard power distribution grid. The communication infrastructure is critical for the successful operation of the modern smart grids. The use of communication technologies ensures the reduction of energy consumption, optimal operation of the smart grid and coordination between all smart grids’ components from generation to the end users. This paper presents an overview of existing communication technologies such as ZigBee, WLAN, cellular communication, WiMAX, Power Line Communication (PLC), their implementation in smart grids, advantages and disadvantages. Moreover, the paper shows comparison of communication infrastructure between the legacy grid and the smart grid and smart grid communication standards. The paper also presents research challenges and future trends in communication systems for smart grid application.
基金Financial support for this research was provided by The Israeli Ministry of Science,Technology,and Space(Grant no.3-10739).
文摘Over the past 20 years,and with greater urgency since the H5N1 papers controversy(2012),dual-use research of concern(DURC)has been extensively debated by the scientific community,regulators,and the public at large.Many have raised the need to regulate DURC;however,despite the urgency of this issue,to date,only two countries have implemented specific regulations,United States and Israel(notably,China is in the final stages of creating a set of DURC-related regulations).In this paper,I have compared these policies as case studies that may benefit other countries.Therefore,the present study aimed to critically compare the DURC policies of the US and Israel and determine whether their different approaches provide a rigorous framework for the regulation of DURC.I have shown that in some aspects,they have adopted similar approaches;for example,allowing local committees to play a role in assessing the research.However,they differ in certain important aspects;for instance,the US policies have laid out a mechanism through which academic institutions and the government decide jointly on how to address risky studies,while the Israeli law places the authority solely in government hands.My aim in comparing the policies is twofold;first,to reveal the weaknesses and strengths of each policy,thereby aiding their improvement,and second,to provide those that are considering developing policies in this field an overview of what the current approaches look like,thereby enabling them to articulate their own approach while taking into account the experience gained by the US and Israel.
