• Title/Summary/Keyword: Distributed Storage

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Evaluation of Semi-Distributed Hydrological Drought using SWSI (Surface Water Supply Index) (SWSI를 이용한 준분포형 수문학적 가뭄 평가)

  • Kwon Hyung-Joong;Kim Seong-Joon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.48 no.2
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    • pp.37-43
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    • 2006
  • A hydrological drought index, MSWSI (Modified Surface Water Supply Index) was suggested based on SWSI (Surface Water Supply Index). With the available data of spatially distributed observation station of precipitation, dam storage, stream water level and natural groundwater level, South Korea was divided into 32 regions. This was conducted to represent the calculated index as a spatially distributed information. Monthly MSWSI was evaluated for the period of 1974 and 2001. It is necessary to compare this result with PDSI (Palmer Drought Severity Index) and SPI (Standard Precipitation Index), and check the applicability of the suggested index in our hydrological drought situation.

3-Dimensional Calculation on Cold Air Flow Characteristics in a Refrigerator (냉장고 내부의 냉기 유동특성에 관한 3차원 해석(I))

  • Oh, Min-Jung;Lee, Jae-Heon;Oh, Myung-Do
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.7 no.3
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    • pp.382-395
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    • 1995
  • A numerical study has been performed on flow characteristics in a domestic refrigerator whose size is $540mm{\times}1,530mm{\times}680mm$, considering existence of a fan and evaporator. The flow field has been simulated with the low Reynolds number $k-\bar{\varepsilon}$ turbulent model and SIMPLE algorithm based on the finite volume method. The region of fan which makes driving force for cold air distribution was modeled as a region in which momentum sources are generated uniformly. The concept of the distributed pressure resistance was applied to describe the momentum loss from evaporator. The result showed that the rate of cold air distribution into freezing room and cold storage room was almost 7 : 3.

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A Design of a PI Compensator for a Bidirectional DC-DC Converter in a DC Distributed Power System

  • Lee, Joonmin;Seok, Bong Jun;La, Jae Du;Kim, Young Seok
    • Journal of international Conference on Electrical Machines and Systems
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    • v.1 no.3
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    • pp.391-396
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    • 2012
  • The Voltage Bus Conditioner(VBC) is a bidirectional DC-DC converter for damping the instability and any transients of the bus voltage in a DC Distributed Power System(DPS). In this paper, a PI controller for the VBC has been designed for the frequency domain. The proposed PI controller not only dampens the bus transients, but also keeps the storage voltage level. Simulation by Matlab/Simulink and experimental results are presented for the validity of the proposed control technique.

Operational Characteristic Analysis of DC Micro-grid with Detail Model of Distributed Generation (분산전원 상세모델을 적용한 DC Micro-grid의 동작특성 분석)

  • Lee, Ji-Heon;Kwon, Gi-Hyun;Han, Byung-Moon;Cha, Han-Ju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.11
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    • pp.2175-2184
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    • 2009
  • This paper describes operational analysis results of the DC micro-grid using detailed model of distributed generation. Detailed model of wind power generation, photo-voltaic generation, fuel-cell generation was implemented with the user-defined model of PSCAD/EMTDC software that is coded with C-language. The operation analysis was carried out using PSCAD/EMTDC software, in which the power circuit is implemented by built-in model and the controller is modelled by user-defined model that is also coded with C-language. Various simulation results confirm that the DC micro-grid can operate without any problem in both the interconnected mode and the islanded mode. The operation analysis result confirms that the DC micro-grid make it feasible to provide power to the load stably. And it can be utilize to develop the actual system design and building.

Optimal File Migration Policies in Distributed Database Systems (분산 데이터베이스 시스템에서의 최적 파일 이동 정책)

  • 이기태;김재련
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.18 no.33
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    • pp.1-10
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    • 1995
  • The allocation of files is essential to the efficiency and effectiveness of a distributed system that must meet geographically dispersed data processing demands. In this paper, we address an optimization model that generates optimal file migration policies in distributed database systems. The proposed model is a more generalized model that includes system's capacity constraints - computing sites' storage capacity and communication networks' capacity - which have not taken into consideration in previous researches. Using this model, we can establish initial file allocation, file reallocation and file migration polices that minimize a system operating cost under system's capacity constraints at an initial system design or reorganization point The proposed model not only can be adopted by small-sized systems but also provides a foundation for effective and simple heuristics for adaptive file migration in large systems.

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Operation Technology of PV-ESS Integrated Module for DC Micro Grid with Constant Power Tracking Algorithm (일정 전력 추종 알고리즘이 적용된 DC 마이크로 그리드용 PV-ESS 통합형 모듈의 운영 기술)

  • Ryu, Kyung;Kim, Jun-Mo;Lee, Jeong;Won, Chung-Yuen
    • The Transactions of the Korean Institute of Power Electronics
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    • v.25 no.6
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    • pp.433-441
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    • 2020
  • This study proposes a constant power tracking algorithm to compensate for the intermittent characteristics of Photovoltaic connected to a DC micro grid. A PV-ESS integrated module in which distributed ESS is additionally connected is utilized for the proposed algorithm. PV performs P&O MPPT control at all times. To supplement the intermittent characteristics of PV, the proposed constant power tracking algorithm maintains constant power by operating the distributed ESS of the PV-ESS integrated module in accordance with the output state of the PV. By performing PSIM simulation and an experiment, this study verifies the performance of the integrated module of PV-ESS for DC micro grids applying the constant power tracking algorithm.

Issues in Next Generation Streaming Server Design

  • Won, Youjip
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2001.11a
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    • pp.335-354
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    • 2001
  • .Next Generation Multimedia Streaming Technology Massive Scale Support $\rightarrow$ Clustered Solution Adaptive to Heterogeneous Network daptive to Heterogeneous Terminal Capability Presentation Technique .SMART Server Architecture .HERMES File System .Clustered Solution . High Speed Storage Interconnect .' Content Partitioning . Load Management . Support for Heterogeniety . Adaptive End to End Streaming Transport: Unicast vs. Multicast '. Scalable Encoding

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A Study of Economic ESS Utilization Based on Supplement Control Plan for Stable Wind Energy Extraction (풍력발전의 전력공급 안정화를 위한 ESS 보조제어 기법과 경제적 용량 산정 연구)

  • Jung, Seungmin
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.1
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    • pp.22-28
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    • 2018
  • In case of developing a combined system by a number of distributed resources with storage device, a number of application suggests a huge capacity can derive operational flexibility both power supply issues or when unexpected situation imposed. However, it is important to determine a resonable energy capacity because the device have many controversial cost issues in current power system industry. An ESS application which focusing essentially required points can induce appropriate storage capacity that required in economic operation. In this paper, a curtailment supporting algorithm based on storage device is introduced, and applied in the capacity calculation method. The main algorithm pursues handling minor exceeding quantities which can cause mechanical load at blade; This paper tries to include it for configuring hybrid algorithm with pitch control. Several fluctuating conditions are utilized in simulation to reflect critical situation. The analyzing process focuses on the control feasibility with applied capacity and control method.

Alcohol Beverage Utensils Represented on the Tomb Mural Paintings of Foreign Exchange Countries with Koryo Dynasty (고려 대외교류국의 고분벽화에 나타난 주구(酒具))

  • Koh, Kyung-Hee
    • Journal of the Korean Society of Food Culture
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    • v.30 no.5
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    • pp.596-610
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    • 2015
  • This study is on the alcohol beverage utensils represented on the Chinese tomb mural paintings of Song, Liao, Jin, and Yuan those countries had foreign exchange with Koryo Dynasty. These mural paintings are distributed in the areas such as Hebei, Henan, Inner mongolia, Shanxi, Shaanxi, Peijing. etc. The Alcohol beverage vessels were classified mainly into storage vessel, pouring vessel, drinking vessel and ladles according to the purpose. The storage vessels of Song, Liao and Jin were called Jiuping, Jingping, Jiuzun as well as Meiping. Pouring vessels are basically one set of Zhuzi, Wenwan and Jiuzhu, or Zhuhu and Zhuwan. On the mural paintings of Yuan Dynasty, Meiping as storage vessels disappear, and a variety of shapes of pouring vessels such as Mayu and Yuhuchunping appear. This trend indirectly indicates the new arrival of distilled liquor, which seems to have affected transition of the alcohol beverage utensils.

Translocation of Seed Storage Proteins into Microsomes Isoalted from Rice Endosperm Cells

  • Kim, Woo Taek
    • Journal of Plant Biology
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    • v.37 no.3
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    • pp.293-299
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    • 1994
  • Developing rice endosperm cells display two morphologically distinct rough endoplasmic reticulum (ER) membranes, the cisternae ER (C-ER) and theprotein body ER (PB-ER), the latter delimiting the prolamine protein bodies. We (Li et al., 1993) have recently shown that the storage protein mRNAs are not randomly distributed on these ER types; the C-ER is enriched for glutelin mRNAs, whereas the PB-ER harbors predominantly prolamine transcripts. To address whether these ER types have differnet capacities to translate these mRNAs and translocate their proteins into the lumen, a microsomal fraction enriched in C-ER vesicles was prepared from devleoping rice seeds. When present in an in vitro translatin system, the microsomes were able to proteolytically remove the signal peptide and internalize both preproglutelin and preprolamine within the microsomal vesicles. Of the two species, preprolamine was more effectively translocated and processed. These results suggest that the C-ER has the capacity to recognize and bind both storage protein mRNAs during protein synthesis. Moreover, efficient translocation and processing of glutelin requires additional factors that are deficient or absent in the in vitro system.

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