• Title/Summary/Keyword: The Grid

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Improved Mesh Grounding Electrode Model by Changing Arrangements of Internal Conductors of the Mesh Grounding Electrode (메쉬접지극의 내부도체 배치에 따른 개선된 메쉬접지극 모델)

  • Shim, Yong-Sik;Choi, Hong-Kyoo;Kim, Tae-Hoon;Song, Young-Joo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.6
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    • pp.60-66
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    • 2010
  • Mesh grounding electrodes in Korea and abroad are designed as lattice-shaped equidistance grounding grids. In case of a lattice-shaped grounding Grid, however, there is a problem of higher touch voltage at the corner of the grid relative to the center. To overcome this problem, we used oblique-shaped equidistance grounding grid to reduce the area of the corner where mesh voltage occurs. As a result the mesh voltage was reduced. Therefore, this paper suggests the use of oblique-shaped grounding grid instead of the existing lattice-shaped ones. It applied the same grounding design dimensions for both lattice-shaped and oblique-shaped grounding grids, compared and analyzed mesh voltage, GPR, ground resistance, total length of grounding conductor, verified that oblique-shaped grounding grid is superior to the lattice-shaped.

Service Prediction-Based Job Scheduling Model for Computational Grid (계산 그리드를 위한 서비스 예측 기반의 작업 스케줄링 모델)

  • Jang Sung-Ho;Lee Jong-Sik
    • Journal of the Korea Society for Simulation
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    • v.14 no.3
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    • pp.91-100
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    • 2005
  • Grid computing is widely applicable to various fields of industry including process control and manufacturing, military command and control, transportation management, and so on. In a viewpoint of application area, grid computing can be classified to three aspects that are computational grid, data grid and access grid. This paper focuses on computational grid which handles complex and large-scale computing problems. Computational grid is characterized by system dynamics which handles a variety of processors and jobs on continuous time. To solve problems of system complexity and reliability due to complex system dynamics, computational grid needs scheduling policies that allocate various jobs to proper processors and decide processing orders of allocated jobs. This paper proposes a service prediction-based job scheduling model and present its scheduling algorithm that is applicable for computational grid. The service prediction-based job scheduling model can minimize overall system execution time since the model predicts the next processing time of each processing component and distributes a job to a processing component with minimum processing time. This paper implements the job scheduling model on the DEVS modeling and simulation environment and evaluates its efficiency and reliability. Empirical results, which are compared to conventional scheduling policies, show the usefulness of service prediction-based job scheduling.

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A Study on Security Issues and Security Technology Policy about Smart Grid Infrastructure (Smart Grid 인프라의 보안성 분석과 보안기술정책 연구)

  • Park, Dea-Woo;Shin, Jin
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2011.06a
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    • pp.165-169
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    • 2011
  • 저탄소 녹색성장 정책의 일환으로 추진되는 Smart Grid 사업은, 전력인프라와 IT인프라가 융합 되면서 지능화된 전기 에너지의 효율성 향상을 목적으로 전기망 내 송배전을 실시간으로 관리할 수 있게 운영하는 지능형 전기망이다. 하지만 기존의 인터넷망과 IT 통신 인프라와 융합되면서 Smart Grid 인프라에서도 IT보안 취약점 문제가 존재한다. 본 논문에서는 Smart Grid 인프라를 요소별로 분석한다. 그리고 Smart Grid 인프라의 보안성 분석을 통하여 보안의 취약점을 가져 올 수 있는 Smart Grid에 대한 보안 이슈를 분석한다. 그리고 Smart Grid 보안성 기준에 따른 보안기술정책을 연구하고, 보안 표준과 보안 방안을 제시한다. 본 연구를 통하여 안전한 Smart Grid 보안기술정책을 위한 법 제정에 기초자료가 될 것이다.

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A Study on the Usefulness of VGR (Virtual Grid Role) Algorithm for Elevation of Image Quality in DR System (DR 시스템에서 화질 개선을 위한 VGR 알고리즘의 유용성에 관한 연구)

  • Yang, Hyun-Jin;Han, Dong-Kyoon
    • Journal of the Korean Society of Radiology
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    • v.14 no.6
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    • pp.763-772
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    • 2020
  • During X-ray examinations in the DR system, the scattered X-rays physically generated by the patient cause image blurring in poor quality. Although X-rays to increase the contrast of images, this increases the patient's exposure dose and is likely to result in grid induced artifacts. Therefore, the purpose of this study is obtain images similar to those of real-grid with non-grid level conditions using a VGR (Virtual Grid Role) algorithm that serves as a virtual grid. Comparing MTF, SNR and CNR of non-grid and VGR algorithm images obtained with 70% exposure conditions of real-grid images showed that the MTF0.5 differed from 0.265 to 0.350 and the MTF0.1 from 0.412 to 0.467 and the SNR, CNR were also different. In addition, comparing MTF, SNR and CNR of VGR algorithm and real-grid images showed that the MTF0.5 differed from 0.350 to 0.367 and the MTF0.1 from 0.467 to 0.483 and the SNR, CNR by little.

Stationary and Moving Computed Radiography Grids : Comparative Observer's Perception (Computed Radiography에서 고정형 그리드와 이동형 그리드 영상의 인식률 비교)

  • Lee, Kiho;Lee, Changhoon;Jin, Gyehwan
    • Journal of the Korean Society of Radiology
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    • v.9 no.7
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    • pp.515-521
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    • 2015
  • This study assessed the degradation of image quality caused by grid artifacts and $moir{\acute{e}}$ pattern artifacts in a stationary grid, and the degradation of image quality caused by cut off artifacts in a moving grid. X-ray images were acquired in a stationary grid and a moving grid with X-ray exposure conditions of 100 cm, 80 kVp, and 30 mA using a CDRAD phantom and a 24 cm thickness acrylic phantom. Observer's perception of X-ray imaging using CDRAD Analyzer was mean 49.36, standard deviation 3.76, maximum 55.56, and minimum 38.67 in the stationary grid, and 47.04, 12.69, 55.56, and 20.89, respectively, in the moving grid. The stationary grid was superior to the moving grid in terms of the mean and standard deviation of observer's perception.

Analysis of Smart Grid Network Vulnerability Using Smart Phone (Smart Phone을 통한 Smart Grid 네트워크 접속에서 취약성)

  • Lee, Jae-Hyun;Park, Dea-Woo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2010.10a
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    • pp.240-243
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    • 2010
  • Smart Phone supplies are diffused and substitute the Internet PC with Mobile communications which they are applied. Smart Phone in Smart Grid where electric power watch and the IT of existing amalgamate are used with business. Consequently from Smart Grid network connections which lead Smart Phone in about connection and control in about security vulnerabilities and Smart Grid networks the research is necessary in about vulnerability. It uses Smart Phone from the present paper and when approaching electric power watch systems which lead Smart Grid networks, it researches in about connection vulnerability. Also it uses Smart Phone and after connecting in Smart Grid networks a vulnerability in seizure possibility and, electric power information and control information, about private data etc. access authority it analyzes with the problem point which occurs it confronts it researches. And the research direction for a security reinforcement under presenting boil in about Smart Grid network security vulnerabilities which lead Smart Phone.

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UI4GSD: Design and Implementation of User Interface for Grid Service Development Based on Globus Toolkit 4 (UI4GSD: 글로버스 툴킷 4 기반 그리드 서비스 개발을 위한 사용자 인터페이스의 설계 및 구현)

  • Kim, Hyuk-Ho;Lee, Pil-Woo;Kim, Yang-Woo
    • Journal of Internet Computing and Services
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    • v.8 no.5
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    • pp.45-58
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    • 2007
  • This paper presents UI4GSD (User Interface for Grid Service Development) for grid service developers that provides an efficient and friendly development environment based on Globus Toolkit 4, Normally, implementing grid service requires special expert knowledge for Grid as well as programming, Moreover, grid service development as well as testing of the deployed service in the Globus container takes a long Time, which makes the grid service implementation very inefficient, However, UI4GSD can automatically generate a grid service interface file, a build file, and grid service class files as well as a client class file, using the information supplied by developers through GUI. In UI4GSD, a grid service is developed easily based on typical five step processes with required input data fed at each step. As, a result, UI4GSD can provide an easy and convenient development environment thereby increasing the efficiency and convenience in developing grid services.

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A Study on the Construction and Deconstruction of the 'Grid' : The Historical Context and Interpretation ('그리드'(Grid)의 형성과 해체 -서양회화의 사적맥락과 그 해석을 중심으로 -)

  • Kim Jai-Kwan
    • Journal of Science of Art and Design
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    • v.1
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    • pp.125-164
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    • 1999
  • The Grid, a lattice structure adapted in paintings, is one of thesimplest plastic structures based on the intersection of horizontal and perpendicular lines. Though mankind has, from the pre-history to the present day, put it to good use in everyday life as a traditional practice or a magical, esoteric, religious emblem in the case of the teciform of primitve art, it was in the paintings of Piet Mondrian that the Grid showed its modern, artistic transformation. As we suggest in the title, before I state the Grid as a plastic construction of modern painting, this dissertation inquires the Grid structure that extends over paintings through the ages as a painterly conept, especially focused on their formation and deconstruction. To begin with, my dissertation investigates, as a historical background, a general idea of the geometrical structure and phases of its transition in art, prior to dealing with the Grids as plastic strures in modern painting. the core of my study on formal Grids is permeated through the third chapter. The first chapter concentrates on, firstly, difining the notion of the Grid and geometrical structure, secondly, searching for a historical backgrounb with whict the so- called modern Grid-paintings come in, inquiring into the formation of the illusion-Grid as aresult of discovering the linear perpective and the situation of the conflict and reconciliaton between reality and illusion. Based on these considerations, the second cecond chapter will examine the various sitations of formation and adaptation of the paintery Grids in the Literalism-Grid, as we have already seen in the chapter one. And the cardinal third chapter devotes itself to the process of the formation of the so-called Object-Grid and Literal-Grid in the Literalism or Minimalism as its logical extension of the Painterly Grid. With it we can get to an interpretation and understanding of the meaning and qualites of Grid dwelt in Modernism thst transformed the structure of Painterly Grid originally as a plane concept to the third dimentionl structure. And then, the fourth chapter, we try to draw a new meaning andre-interpretation of the Formal-Grid as a representatuinnal structure appeared in the post-modernist paintings, going with its deconstructional situation. Therefore, we can, in our study on Grids, see the various points of view in the interpretation of them as illusion-structure, as plane-structure, and as cubic-structure; its concept differs form times, oscillating between its formation and deconstruction. The Grid, as we have seen in my dissertation, contains various problems and significations in art that deserve to investigate throughly, including some important plastic problem such as space and plane, and, in the case of do-grid, time. We may expect new concepts of it that will have difference meanings. 1 hope my study makes some contributions to understanding the coordination of the abstruse modern and contemporary art.

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A Study on Image Change according to Grid Ratio in Digital Radiography (디지털 방사선에서 격자 비에 따른 영상변화에 관한 연구)

  • Sung-Hun Jeong
    • Journal of radiological science and technology
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    • v.46 no.2
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    • pp.89-97
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    • 2023
  • With the introduction of the D.R system, the grid with high removal rate of scattered radiation is selected and used without considering the grid performance evaluation. Despite the high removal rate of scattered radiation belonging to high grid ratio, it is also possible to see the cut-off phenomenon in which the primary ray involved in the formation of image could be removed as well. Thus, the purpose of this study is to provide the basic data for researches on the usefulness of using the grid by presenting the appropriate grid ratio in the D.R system through the measurement of image in grid such as non-grid, 6:1, 8:1, 10:1, 12:1. The equipments used for this study were radiation generator with grid in 12:1, 10:1, 8:1, 6:1, indirect-type detector, and acryl phantom. As the study for image evaluation, this study measured the SNR, PSNR, MSE, and Entropy. In the results of this study, the PSNR was the highest in 6:1 and the lowest in 8:1. The SNR was high in 6:1 and 8:1, and the lowest in 12:1. In case of Entropy, it was high in 8:1 and 10:1, and the lowest in 12:1. Therefore, when the grid is used, it would be more proper to choose the grid in 8:1 or 10:1 with less loss in information content of primary ray rather than the high grid ratio showing the increased patient exposure dose.

A Review on the Grid-Connected Technology of the Distributed Energy Resources (분산형전원의 계통연계기술 리뷰)

  • Lee, Kyungsoo
    • Proceedings of the KIPE Conference
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    • 2014.07a
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    • pp.371-372
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    • 2014
  • This review focuses on grid-connected technology for distributed energy resources(DER). The grid-connected technology is categorized into three classifications: 1) protection function; 2) power quality improvement function; 3) grid stabilization fuction. Grid codes comparison of Japan, USA, EU and Korea is also described in the paper.

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