• Asia pacific journal of information systems
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• 제27권2호
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• pp.99-125
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• 2017

In this study, we propose an operations model to automate a home energy management system (HEMS) that utilizes an energy storage system (ESS) in consideration of consumer utility. Most previous studies focused on the system for the profits obtained from trading charged energy using large-scale ESS. By contrast, the present study focuses on constructing a home-level energy management system that considers consumer's utility over energy consumption. Depending on personal preference, some residential consumers may prefer consuming additional energy to earn increased profits through price arbitrage and vice versa. However, the current system could not yet reflect on this aspect. Thus, we develop an operations model for HEMS that could automatically control energy consumption while considering the level of consumer's preference and the economic benefits of using an ESS. The results of simulations using a dataset of the Korean market show that an operations policy of charging and discharging can be changed depending on consumer's utility. The impact of this policy is not ignorable. Moreover, the technical specifications of ESS, such as self-discharge rate and round-trip efficiency, can affect the operations policy and automation of HEMS.

• 토지주택연구
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• 제9권1호
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• pp.19-28
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• 2018

The purpose of this study is to explore an implication for new perspectives and concrete approaches to Korean Land Banking by analyzing the role of the Land Bank and the Land Storage System in the formation of Chinese Land Market, Land Management, and City Management. Time scope of this research focused on Chinese reform and opening since 1978, when study of land bank began to be actively performed in China. Research targets were Land Bank and Land Storage System related to Chinese Land System, and this research targeted Chinese Land Storage System as research object, which seem to have similar tendency to Korean Land Banking System, after examining the concept of Land Bank and Land Storage System. As the research method, this research arranged the contents and changes of policy based on discussed research documents over Chinese Land Bank and Land Storage System till today since the foundation of the nation. Later, this research investigated the realistic reflection and in-depth investigation of the problems through the operational mechanism and concrete case study of Chinese Land Storage System, a similar policy to Korean land bank, the researchers will look into the reality reflected and will carry out a in-depth study of the problems. China has established its characteristic socialistic market economy system, partly adopting the concept of capitalism, supporting socialism. This way, the researcher considers that such socialistic economic factors with strong welfare aspects can be adopted also in Korea, where capitalistic market economy system is maintained, and be utilized as a new measure for development strategy.

• 디지털콘텐츠학회 논문지
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• 제12권2호
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• pp.141-150
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• 2011

최근 다양한 기기에서 플래시 메모리 저장장치인 SSD가 활용되고 있다. SSD 기반 시스템에서 기존 하드 디스크 기반 버퍼 교체 알고리즘은 플래시 메모리의 특성을 고려하지 않고 이는 시스템의 성능 저하의 원인이 된다. 본 논문에서는 SSD의 특성을 고려하여 읽기 버퍼와 쓰기 버퍼를 분리하고 각각의 버퍼에 서로 다른 크기의 교체 단위와 서로 교체 알고리즘을 적용하는 ABM (Asymmetric Buffer Management) 정책을 제안한다. 추가적으로 제안한 정책을 보완하기 위해 쓰기 교체 지연 정책, 동적 크기 적응화 알고리즘을 적용하였다. 제안한 ABM 정책은 효과적으로 성능을 향상시키는 것으로 나타났으며, 특히 여러 알고리즘 중 가장 성능이 좋은 ABM-LRU-CLC의 경우 기존의 LRU에 비해 최대 32% 성능이 향상되는 것으로 나타났다.

• 한국태양광발전학회지
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• 제6권1호
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• pp.56-68
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• 2020

Cameroon is a lower middle-income country with a population of 25.87 million inhabitants distributed over a surface area of 475,442 ㎢. Cameroon has very rich potentials in renewable energy resources such as solar energy, wind energy, small hydropower, geothermal energy and biomass. However, renewable energy constitutes less than 0.1% of energy mix of the country. The energy generation mix of Cameroon is dominated by large hydropower and thermal power. Cameroon ratified the Paris Agreement in July 2016 with an ambitious 20% greenhouse gas (GHG) emission reduction. This study attempts to investigate some renewable energy deployment policy-instruments that could enable the country enhance renewable energy deployment, gain energy independence, fulfill Nationally Determined Contribution (NDC) and achieve Sustainable Development Goals. It begins with an analysis of the status of energy sector in Cameroon. It further highlights the importance of renewable energy in mitigating climate change by decarbonizing the energy mix of the country to fulfill NDC and SDGs. Moreover, this study proposes some renewable energy deployment policy-solutions to the government. Solar energy is the most feasible renewable energy source in Cameroon. Feed-in Tariffs (FiT), is the best renewable energy support policy for Cameroon. Finally, this study concludes with some recommendations such as the necessity of building an Energy Storage System as well a renewable energy information and statistics infrastructure.

• 한국통신학회논문지
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• 제25권10B호
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• pp.1648-1664
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• 2000

This paper proposes a real-time dynamic storage allocation algorithm QSHF(quick-segregated-half-fit) that provides various memory allocation policies. that manages a free block list per each word size for memory requests of small size good(segregated)-fit policy that manages a free list per proper range size for medium size requests and half-fit policy that manages a free list per proper range size for medium size requests and half-fit policy that manages a free list per each power of 2 size for large size requests. The proposed algorithm has the time complexit O(1) and makes us able to easily estimate the worst case execution time(WCET). This paper also suggests two algorithm that finds the proper free list for the requested memory size in predictable time and if the found list is empty then finds next available non-empty free list in fixed time. In order to confirm efficiency of the proposed algorithm we simulated the memory utilization of each memory allocation policy. The simulation result showed that each policy guarantees the constant WCET regardless of memory size but they have trade-off between memory utilization and list management overhead.

• Water Engineering Research
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• 제3권1호
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• pp.57-62
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• 2002

This research is intended to integrate long-term operation rules and real time operation policy for conservation & flood control in a reservoir. The familiar Yield model has been modified and used to provide long-term rule curves. The model employs linear programming technique under given physical conditions, i.e., total capacity, dead storage, spillways, outlet capacity and their respective elevations to find required and desired minimum storage fur different demands. To investigate the system behavior resulting from the above-mentioned operating policy, i.e., the rule curves, the simulation model was used. Results of the simulation model show that the results of the optimization model are indeed valid. After confirmation of the above mentioned rule curves by the simulation models, gate operation procedure was merged with the long term operation rules to determine the optimum reservoir operating policy. In the gate operation procedure, operating policy in downstream flood plain, i.e., determination of damaging and non-damaging discharges in flood plain, peak floods, which could be routed by reservoir, are determined. Also outflow hydrograph and variations of water surface levels for two known hydrographs are determined. To examine efficiency of the above-mentioned models and their ability in determining the optimum operation policy, Esteghlal reservoir in Iran was analyzed as a case study. A numerical model fur the solution of two-dimensional dam break problems using fractional step method is developed on unstructured grid. The model is based on second-order Weighted Averaged Flux(WAF) scheme with HLLC approximate Riemann solver. To control the nonphysical oscillations associated with second-order accuracy, TVD scheme with SUPERBEE limiter is used. The developed model is verified by comparing the computational solutions with analytic solutions in idealized test cases. Very good agreements have been achieved in the verifications.

• 한국컴퓨터정보학회논문지
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• 제25권2호
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• pp.1-10
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• 2020

본 논문에서는 향상된 히트율과 더 적은 낸드 플래시 메모리 쓰기 연산을 할당하는 디스크 버퍼 교체 정책을 소개한다. 플래시 메모리는 높은 집적도, 높은 신뢰성 및 비휘발성이라는 특징을 가지고 있어 최근 많은 곳에서 사용되고 있다. 하지만 삭제 이후 쓰기 연산 문제, 비대칭적인 연산 속도와 짧은 수명 등의 한계점도 가지고 있다. 이런 문제를 개선하기 위해 본 논문에서는 2WPR 정책을 소개한다. 2WPR 정책은 디스크 버퍼의 각 페이지마다 이후 재참조될 가능성, 각 지역성 및 쓰기 연산에 대한 가중치 분석을 통해 교체할 페이지를 선택한다. 제안된 새로운 정책은 기존 디스크 버퍼 관리 정책에 비해 히트율을 최대 10%까지 향상시킬 수 있으며 플래시 메모리에 대한 쓰기 연산을 최대 5%까지 감소시킬 수 있었다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2009년도 추계학술발표대회
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• pp.77-78
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• 2009

In this paper, we study a pattern-aware write cache policy using a NAND flash memory in disk-based mobile storage systems. Our work is designed to face a mix of a number of sequential accesses and fewer non-sequential ones in mobile storage systems by redirecting the latter to a NAND flash memory and the former to a disk. Experimental results show that our policy improves the overall I/O performance by reducing the overhead significantly from a non-volatile cache over a traditional one.

• 디지털융복합연구
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• 제12권9호
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• pp.153-158
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• 2014

협업을 위한 클라우드 스토리지란 협업에 참여하는 사용자들이 클라우드 스토리지를 공유하여 이용하는 것을 말한다. 협업에 이용되는 클라우드 스토리지는 여러 사람이 새로운 데이터를 저장하고 다른 사용자의 저장된 데이터를 읽을 수 있기 때문에 협업에 참여하는 사용자에 대한 인증과 데이터 보호의 문제가 일반의 그것보다 더 중요하다 할 것이다. 이에 본 논문에서는 협업을 위한 클라우드 스토리지를 공유하는 사용자에 대한 인증 방법과 저장된 데이터를 보호하는 방법을 제안하고자 한다.

• 설비공학논문집
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• 제24권10호
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• pp.733-738
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• 2012

It is important issue to reduce the electric energy to save the operating cost of HVAC system. Even if electrical energy is the clean energy, it is difficult and takes high cost for storage of electricity. These cause the high peak load of electric energy for HVAC in summer season. In korea, government impose the electric charge with several grade for the purpose of cut-off the peak load of electricity. Government has a policy to support to design and install the heat/ice storage system using midnight electricity. In this study, analysis of cooling load and operating characteristics for ice storage system are performed. And, also economical efficiency is compared between ordinary charge system of electricity and midnight rate charge of electricity. The systematic and economical supports are needed for expansion of usage of energy saving equipments.