• 제목/요약/키워드: dynamic power management

검색결과 271건 처리시간 0.026초

Adaptive Online Voltage Scaling Scheme Based on the Nash Bargaining Solution

  • Kim, Sung-Wook
    • ETRI Journal
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    • 제33권3호
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    • pp.407-414
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    • 2011
  • In an effort to reduce energy consumption, research into adaptive power management in real-time systems has become widespread. In this paper, a novel dynamic voltage scaling scheme is proposed for multiprocessor systems. Based on the concept of the Nash bargaining solution, a processor's clock speed and supply voltage are dynamically adjusted to satisfy these conflicting performance metrics. In addition, the proposed algorithm is implemented to react adaptively to the current system conditions by using an adaptive online approach. Simulation results clearly indicate that the superior performance of the proposed scheme can strike the appropriate performance balance between contradictory requirements.

The Investor's Behavior in Competitive Korean Electricity Market

  • Ahn, Nam-Sung;Kim, Hyun-Shil
    • 한국시스템다이내믹스연구
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    • 제6권2호
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    • pp.25-35
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    • 2005
  • This paper describes the mechanism for new investment to appear in waves of boom and bust causing alternative periods of over and under supply of electricity in Korean market. A system dynamics model was developed to describe the dynamic behavior of new investment in Korean market. The simulation results show the boom and bust cycle in the new investments. When the market price is high, investors decide to build new power plants. However, it takes some delay time to complete new power plants. When the new power plants are being added into the grid, the supply increases and the wholesale price begins to decrease. This causes the cancellation of new power plant or delay the construction. This mechanism causes the boom and bust cycle in new investment.

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Study of Bidirectional DC-DC Converter Interfacing Energy Storage for Vehicle Power Management Using Real Time Digital Simulator (RTDS)

  • Deng, Yuhang;Foo, Simon Y.;Li, Hui
    • Journal of Power Electronics
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    • 제11권4호
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    • pp.479-489
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    • 2011
  • The bidirectional dc-dc converter, being the interface between Energy Storage Element (ESE) and DC bus, is an essential component of the power management system for vehicle applications including electric vehicle (EV), hybrid electric vehicle (HEV), and fuel cell vehicle (FCV). In this paper, a novel multiphase bidirectional dc-dc converter interfacing with battery to supply and absorb the electric energy in the FCV system was studied with the help of real time digital simulator (RTDS). The mathematical models of fuel cell, battery and dc-dc converter were derived. A power management strategy was developed and first simulated in RTDS. A Power Hardware-In-the-Loop (PHIL) simulation using RTDS is then presented. The main challenge of this PHIL is the requirement for a highly dynamic bidirectional Simulation-Stimulation (Sim-Stim) interface. This paper describes three different interface algorithms. The closed-loop stability of the resulting PHIL system is analyzed in terms of time delay and sampling rate. A prototype bidirectional Sim-Stim interface is designed to implement the PHIL simulation.

가정용 연료전지 운전 모드 해석을 위한 동특성 모델 개발 (A Dynamic Simulation Model for the Operating Strategy Study of 1 kW PEMFC)

  • 유상석;이영덕;홍동진;안국영
    • 한국수소및신에너지학회논문집
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    • 제19권4호
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    • pp.313-321
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    • 2008
  • Dynamics of the proton exchange membrane fuel cell is specially important when the system is frequently working on transient conditions. Even though the dynamics of proton exchange membrane fuel cell for residential power generation is less critical than that of PEMFC for transportation application, the system dynamics of PEMFC for RPG can be very important for daily start-up and stop. In particular, thermal management of the PEMFC for RPG is very important because the heat generation from electrochemical reaction is delivered to the home for hot water usages. Additionally, the thermal management is also very important for heat balance of the system and temperature control of the fuel cell. The objective of this study is to develop a dynamic system model for the study of PEMFC performance over various BOP options. Basic simulation results will be presented.

DDNS 기반 가정 에너지 관리 시스템 설계 (Design For System Algorithm for Implement Machine Socialization Environment)

  • 이춘희;김웅준;정회경
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2015년도 춘계학술대회
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    • pp.629-631
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    • 2015
  • 최근 전기 사용량의 실제 수요가 예측 수요를 벗어남에 따라 나타나는 전력 수급의 불안감을 해결하기 위하여 정부는 보다 효율적인 에너지 관리에 많이 노력을 하고 있다. 2011년 국내최초의 대규모 정전사태인 블랙아웃 사태이후 현재 우리나라의 전력 설비 예비율은 10% 이하로서 전력수급위기는 반복되고 있다. 또한, 에너지 관리 시스템에 대한 관심과 수요는 사회 전 분야로 확대되고 있다. 본 논문에서는 건물 내 전력수급을 최적화하기 위해 유무선 공유기와 DDNS(Dynamic Domain Name Service)를 이용하여 전기 소비 장치의 원격제어 및 모니터링을 위한 Presonal Energy Management System 설계한다. 향후, 원격제어 및 접속에 대한 사용자의 설정을 최소화할 수 있는 방안에 대한 추가적인 연구가 필요하다.

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원전 방진기 검사 및 관리 현황 (Status of Inspection and Management for Nuclear Power Plants Snubbers)

  • 조용배;문균영;유현주
    • 한국압력기기공학회 논문집
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    • 제10권1호
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    • pp.20-24
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    • 2014
  • Recently, it is getting more and more important ensuring the integrity for the equipment degradation according to the increase of nuclear power plant operating period. In many equipment of the nuclear power plant, snubbers mainly installed in reactor coolant pumps, steam generators and piping protected the equipment and piping from the occurrence of transient dynamic loads such as the earthquake, thermal load during the plant operation. This report describes the function, regulation, inspection requirements and management status of the snubbers installed in domestic nuclear power plants.

Bank's Market Power and Firm Access to Capital Markets in Asia

  • Lee, Sunglyong;Seol, Youn
    • Management Science and Financial Engineering
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    • 제19권1호
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    • pp.43-47
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    • 2013
  • We investigate the effect of bank's market power on financing constraints of non-financial firms in 11 Asian countries between 1995 and 2009. Using firm-level data we analyze financial constraints with the Euler equation derived from the dynamic investment model. We find that with a highly concentrated banking sector firms which have high market power are less financially constrained. These results are consistent with an information-based hypothesis that more market power increases bank's advantage to produce information on potential borrowers.

계통연계형 풍력, 태양광 및 축전지 하이브리드 시스템의 출력제어 및 동특성 해석 (Power Control and Dynamic Performance Analysis of a Grid-Interactive Wind/PV/BESS Hybrid System)

  • 김슬기;전진홍;조창희;안종보
    • 전기학회논문지
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    • 제56권2호
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    • pp.317-324
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    • 2007
  • Most conventional hybrid systems using renewable energy sources have been applied for stand-alone operation, but Utility-interface may be an useful and viable option for hybrid systems. Grid-connected operation may have benefits such as reduced losses in power system distribution, utility support in demand side management, and peak load shaving. This paper addresses power control and dynamic performance of a grid-connected PV/wind/BESS hybrid system. At all times the PV way and the wind turbine are individually controlled to generate the maximum energy from given weather conditions. The battery energy storage system (BESS) charges or discharges the battery depending on energy gap between grid invertger generation and production from the PV and wind system. The BESS should be also controlled without too frequently repeated shifts in operation mode, charging or discharging. The grid inverter regulates the generated power injection into the grid. Different control schemes of the grid inverter are presented for different operation modes, which include normal operation, power dispatching, and power smoothing. Simulation results demonstrate that the effectiveness of the proposed power control schemes for the grid-interactive hybrid system.

퍼지 논리를 이용한 연료전지/축전지 하이브리드 시스템의 운전제어 (Energy management strategies of a fuel cell/battery hybrid system using fuzzy logics)

  • 정귀성;이원용;김창수
    • 한국수소및신에너지학회논문집
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    • 제15권1호
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    • pp.1-11
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    • 2004
  • Hybrid power systems with fuel cells and batteries have the potential to improve the operation efficiency and dynamic response. A proper load management strategy is important to better system efficiency and endurance in hybrid systems. In this paper, a fuzzy logic algorithm has been used to determine the fuel cell output power depending on the external required power and the battery state of charge(SoC). If the required power of the hybrid system is small and the SoC is small, then the greater part of the fuel cell power is used to charge the battery pack. If the required power is relatively big and the SoC is big, then fuel cell and battery are concurrently used to supply the required power. These IF-THEN operation rules are implemented by fuzzy logic for the energy management system of hybrid system. The strategy is evaluated by simulation. The results show that fuzzy logic can be effectively used to optimize the operational efficiency of hybrid system and to maintain the battery SoC properly.

Knowledge-driven Dynamic Capability and Organizational Alignment: A Revelatory Historical Case

  • Kim, Gyeung-Min
    • Asia pacific journal of information systems
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    • 제20권1호
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    • pp.33-56
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    • 2010
  • The current business environment has been characterized as less munificent, highly uncertain and constantly evolving. In this environment, the company with dynamic capability is reported to be more successful than others in building competitive advantage. Dynamic capability focuses on the link between a dynamically changing environment, strategic agility, architectural reconfiguration, and value creation. Being characterized to be flexible and adaptive to market circumstance changes, an organization with dynamic capability is described to have high resource fluidity, which represents business process, resource allocation, human resource management and incentives that make business transformation faster and easier. Successful redeployment of the resources for dynamic adaptation requires organizational forms and reward systems to be well aligned with firm's technological infrastructures and business process. The alignment is considered to be an executive level commitment. Building dynamic capability is knowledge driven; relying on new knowledge to reconfigure firm's resources. Past studies established the link between the effective execution of a knowledge-focused strategy and relevant setting of architectural elements such as human resources, structure, process and information systems. They do not, however, describe in detail the underlying processes by which architectural elements are adjusted in coordinated manners to build knowledge-driven dynamic capability. In fact, understandings of these processes are one of the top issues in IT management. This study analyzed how a Korean corporation with a knowledge-focused strategy aligned its architectural elements to develop the dynamic capability and thus create value in the dynamically changing markets. When the Korean economy was in crisis, the company implemented a knowledge-focused strategy, restructured the organization's architecture by which human and knowledge resources are identified, structured, integrated and coordinated to identify and seize market opportunity. Specifically, the following architectural elements were reconfigured: human resource, decision rights, reward and evaluation systems, process, and IT infrastructure. As indicated by sales growth, the reconfiguration helped the company create value under an extremely turbulent environment. According to Ancona et al. (2001), depending on the types of lenses the organization uses, different types of architecture will emerge. For example, if an organization uses political lenses focusing on power, influence, and conflict. the architecture that leverage power and negotiate across multiple interest groups would emerge. Similarly, if an organization uses economic lenses focusing on the rational behavior of organizational actors making choices based on the costs and benefits of action, organizational architecture should be designed to motivate and provide incentives for the actors (Smith, 2001). Compared to this view, information processing perspectives consider architecture to be designed to maximize the capacity of information processing by the actors. Using knowledge lenses, the company studied in this research established architectural elements in a manner that allows the firm to effectively structure knowledge resources to form dynamic capability. This study is revelatory single case with a historic perspective. As a result of this study, a set of propositions and a framework are derived, which can be used for architectural alignment.