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국내 배편계통의 최적 연계(안) (The Optimal Number of Dividing and Connecting Per Feeder in Korea Distribution System)

  • 조남훈;김건중;김재철
    • 대한전기학회논문지:전력기술부문A
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    • 제51권7호
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    • pp.349-361
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    • 2002
  • Occasionally, equipment in a distribution system fails due to damage from weather, vandalism, or other causes. Failures and unexpected events do not always occur as and where expected. Therefore, a good contingency plan, multi-zone or otherwise, provides flexibility by locating switches at various strategic locations so that parts of a feeder can be picked up in the event of line outages at various places. It is possible to create feeder system layout that achieve remarkable contingency support economics, even as their normal peak loading levels approach thermal capacity, by utilizing six, seven, or even nine switchable zones per feeder. But many switchable zones per feeder are of questionable practicality and effectiveness, because of the complexity and time required for the switching operation. In practice, a zonal scheme with between three and four zones will usually provide complete contingency backup for all feeders. Line switches have both capital and maintenance costs, the planning for multi-zonal schemes is considerably more difficult than or loop or single-zone systems, and the required switching operations required during contingencies take more time. But multi-zonal schemes are used because these costs come to far less than the cost of additional capacity required for loop or single-zone. In this paper, we present the optimal number of switchable zones per feeder in Kora distribution system.

비행시험 데이터를 통한 추진제탱크 가압가스 요구량 예측 프로그램 검증 (Verification of Required Pressurant Mass Prediction Program for Propellant Tank through Flight Test Data)

  • 권오성;한상엽;조인현;고영성
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2010년도 제35회 추계학술대회논문집
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    • pp.723-725
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    • 2010
  • 추진제탱크의 가압에 소요되는 가압가스 요구량을 예측하기 위해 개발된 프로그램을 비행시험 데이터를 통해 검증하였다. 개발된 예측 프로그램은 이미 지상에서의 시험데이터를 통해 검증되었으나, 프로그램의 신뢰성을 높이기 위하여 2002년 발사된 3단형과학로켓(KSR-III)의 비행시험 데이터와 비교하였다. 비행시험에서는 추진제탱크로 유입되는 가압가스의 온도를 측정하지 않았으므로 데이터 분석을 통하여 적절한 온도를 가정하였다. 수치해석 프로그램과 비행시험 데이터 비교 결과 가압가스 요구량에 있어 약 6%의 오차를 보여줌으로써 예측 프로그램의 유효성을 입증하였다.

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PREDICTION OF THE DETECTION LIMIT IN A NEW COUNTING EXPERIMENT

  • Seon, Kwang-Il
    • 천문학회지
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    • 제41권4호
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    • pp.99-107
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    • 2008
  • When a new counting experiment is proposed, it is crucial to predict whether the desired source signal will be detected, or how much observation time is required in order to detect the signal at a certain significance level. The concept of the a priori prediction of the detection limit in a newly proposed experiment should be distinguished from the a posteriori claim or decision whether a source signal was detected in an experiment already performed, and the calculation of statistical significance of a measured source signal. We formulate precise definitions of these concepts based on the statistical theory of hypothesis testing, and derive an approximate formula to estimate quickly the a priori detection limit of expected Poissonian source signals. A more accurate algorithm for calculating the detection limits in a counting experiment is also proposed. The formula and the proposed algorithm may be used for the estimation of required integration or observation time in proposals of new experiments. Applications include the calculation of integration time required for the detection of faint emission lines in a newly proposed spectroscopic observation, and the detection of faint sources in a new imaging observation. We apply the results to the calculation of observation time required to claim the detection of the surface thermal emission from neutron stars with two virtual instruments.

ITT Platform의 복화율 개선에 따른 효과 분석 - 부산항 신항을 대상으로 - (The Evaluation of Backhaul Transport with ITT Platform - The Case of Busan New Port -)

  • 박남규;이정훈
    • 수산해양교육연구
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    • 제29권2호
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    • pp.354-364
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    • 2017
  • This study tries to evaluate the effect of ITT introduction in Busan New Port. The study used the estimation model of the number of vehicles required in accordance with the backhaul rate. The model used big data, COPINO e-document for one year in 2015. COPINO recorded the event such as truck ID, container ID, ATA, damage etc when truck arrived at gate. The study finds important information to estimate the required number of trucks for handling current ITT containers in Busan New Port: Daily throughput in Busan New Port is 1650 vans, especially night throughput recorded peak level in 1800 hours to 2400 hours, the throughput between adjacent terminals recorded high, i.e PNIT to HPNT. The transportation capability for 6 hours between terminals is from 4 vans to 7 vans. The required trucks are estimated 89 currently without considering peak level. If we change the back haul rate from current 20% to 40%, 60% and 80%, how much would the cost drop? It was discovered that, if it is raised to 40%, 60% and 80%, the number of vehicle required will be reduced from 89 (current) to 76, 65 and 59. It was also discovered that the total savings will reduce down to 12%, 25% and 34%.

Flow Characteristics Analysis for the Chemical Decontamination of the Kori-1 Nuclear Power Plant

  • Cho, Seo-Yeon;Kim, ByongSup;Bang, Youngsuk;Kim, KeonYeop
    • 방사성폐기물학회지
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    • 제19권1호
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    • pp.51-58
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    • 2021
  • Chemical decontamination of primary systems in a nuclear power plant (NPP) prior to commencing the main decommissioning activities is required to reduce radiation exposure during its process. The entire process is repeated until the desired decontamination factor is obtained. To achieve improved decontamination factors over a shorter time with fewer cycles, the appropriate flow characteristics are required. In addition, to prepare an operating procedure that is adaptable to various conditions and situations, the transient analysis results would be required for operator action and system impact assessment. In this study, the flow characteristics in the steady-state and transient conditions for the chemical decontamination operations of the Kori-1 NPP were analyzed and compared via the MARS-KS code simulation. Loss of residual heat removal (RHR) and steam generator tube rupture (SGTR) simulations were conducted for the postulated abnormal events. Loss of RHR results showed the reactor coolant system (RCS) temperature increase, which can damage the reactor coolant pump (RCP)s by its cavitation. The SGTR results indicated a void formation in the RCS interior by the decrease in pressurizer (PZR) pressure, which can cause surface exposure and tripping of the RCPs unless proper actions are taken before the required pressure limit is achieved.

개질형 On-Site 수소충전소의 리스크 감소를 위해 요구되는 SIL 등급 달성 방안에 관한 연구 (A Study on the Achievement of Required Safety Integrity Level to Reduce Risk for SMR On-Site Hydrogen Refueling Stations)

  • 이진호;임재용
    • 한국안전학회지
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    • 제35권6호
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    • pp.1-8
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    • 2020
  • In recent years, hydrogen has received much attention as an alternative energy source to fossil fuels. In order to ensure safety from the increasing number of hydrogen refueling stations, prevention methods have been required. In this regard, this study suggested an approach to reduce the risk of hydrogen refueling station by increasing Safety Integrity Level (SIL) for a Steam Methane Reformer (SMR) in On-Site Hydrogen Refueling Station. The worst scenario in the SMR was selected by HAZOP and the required SIL for the worst scenario was identified by LOPA. To verify the required SIL, the PFDavg.(1/RRF) of Safety Instrumented System (SIS) in SMR was calculated by using realistic failure rate data of SIS. Next, several conditions were tested by varying the sensor redundancy and proof test interval reduction and their effects on risk reduction factor were investigated. Consequently, an improved condition, which were the redundancy of two-out-of-three and the proof test interval of twelve months, achieved the tolerable risk resulting in the magnitude of risk reduction factor ten times greater than that of the baseline condition.

Boundary Condition for Bare Chassis Brackets of the Commercial Vehicle

  • Yang, Seung Bok
    • International journal of advanced smart convergence
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    • 제11권1호
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    • pp.94-100
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    • 2022
  • It is common for commercial vehicles to make the top part according to the use after making the bear chassis, and to connect various devices with the bear chassis. Various brackets used in bear chassis for the development of all automobiles, including commercial vehicles, play a role of connecting the components required for driving and operating the car to the car body. In commercial vehicles, components necessary for operation are installed in the bear chassis; that is, the bear chassis of commercial vehicles is a space where the devices required for driving and operating the vehicle are installed. The devices required for the configuration of the vehicle are drive, brake, exhaust and steering, etc. These devices are basically connected to the body, the front axis, or the rear axis. The part interlinking the apparatuses required for the vehicle drive to the car body or axis is bracket. In this study, we analyzed the boundary conditions to evaluate the stability of the three brackets that connect the components of the car to the front axis of the new type of 30-seater bus in the development process. In order to analyze the boundary conditions, the boundary conditions according to the driving condition of the vehicle were classified. For stress analysis to evaluate the stability of brackets according to the driving state of the vehicle, it is reasonable to give the bracket a boundary condition of harsh conditions.

지능형 주거 서비스 개발을 위한 고령자 행위 사례분석 연구 - 24시간 자기기입식 행위 분석을 중심으로 - (A Case Study on the Elderly People's Behavior for Developing Smart Home Service - Focus on analyzing behaviors filling up by oneself for 24hours-)

  • 이현수;정현원;정지예;박성준
    • 한국실내디자인학회논문집
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    • 제21권1호
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    • pp.11-19
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    • 2012
  • The purpose of this study is to categorize elderly people's behavior using the questionnaire filling up by oneself for 24hours and to analyze the time required according to behavior and space. Also, through analytical researches, we find a way to develop smart home service. In this study, we carry out a questionnaire targeting a number of 20 elderly people. The questionnaire is to survey elderly people's behaviors for 24hours. Questionnaire items consist of three parts : items for checking time required about a daily behavior, items for analyzing a space in daily lives, generalities. This study is analyzed through descriptive statistics. The results of this study were as follows. Firstly, the elderly people's behaviors were eight categories. Among these behavior's categories, the highest portion is the behavior related to Individual maintenance such as sleep, personal hygiene, nap, etc. by 49%. Secondly, the portion of time required in residence based on daily lives is higher than outside of residence by 73%. Lastly, analyzing each space in residence focused on time required of elderly people's behaviors, bed room is the highest portion by 49%, and followed by living room with 29% and kitchen with 15%, and bath room with 7%.

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디지털 TV EPG 사용자 요구 기능 도출 및 워킹 프로토타잎 개발 (Deriving required functions and developing a working prototype of EPG on digital TV)

  • 박지수;이우훈;류동석
    • 대한인간공학회지
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    • 제23권2호
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    • pp.55-80
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    • 2004
  • Multichannel on digital TV not only gave opportunities to the TV audience to view a wide range of programs. but also made it difficult for them to search for the program which they plan to view among over 1000 programs broadcasted on more than 100 channels. In this paper the functions of EPG (Electronic Program Guides) required by the users on digital TV were derived from the systematic analysis of multichannel viewing situations. In the situation analysis the situations where they viewed programs on more than 100 channels were generated systematically and the viewing processes in those situations were analyzed to identify user needs and derive the required functions of EPG. We surveyed the viewing behavior of the audience who subscribed to a digital satellite broadcast. SkyPerfecTV. in Tokyo. Japan. The purpose of the survey was to verify the validity of the functions derived from the situation analysis and to identify hidden user needs which were difficult to in the situation analysis. The functions were implemented on a working prototype of EPG based on a digital TV simulator which broadcasts 500 programs on 100 channels and can be controlled by three working prototypes of personal remote controllers. The working prototype will be used in Participatory Design to make it possible for the users to experience and verify the usefulness of the required functions of EPG and also find problems in user interface design of EPG

분말 시료의 투과전자현미경 직접 가열 실험법 연구 (An Investigation of In Situ TEM Heating Experiments of Powder Samples)

  • 김윤중;정종만;이영부;이수정;송지호
    • Applied Microscopy
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    • 제31권4호
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    • pp.315-323
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    • 2001
  • Kaolinite분말 시료를 이용한 TEM 직접 가열 실험에서 얻은 결론은 아래와 같다. (1) Gatan사의 가열 시료지지대에서 사용하고 있는 증류수 순환장치는 $500^{\circ}C$이상의 가열 실험에서 시료의 유동을 막는 필수적인 장비이다. (2) $600^{\circ}C$이하의 가열 실험에서는 분말의 두께에 따른 상전이 진행정도의 차이가 나타나기 때문에 앙은 시편과 두꺼운 시편을 고루 관찰하는 노력이 필요하다. (3) $900^{\circ}C$ 이상의 고온 가열 실험에서는 융점이 높은 Mo-grid의 사용이 필수적이다. 전체적으로 온도 상승률이나 온도 지속 시간이 상전이 과정에 미치는 영향이 증가하기 때문에 이들의 정량적인 제어가 가능한 자동제어방식의 사용이 필요하다. (4) 단면 관찰을 위해 고온용 epoxy에 포매된 kaolinite분말의 TEM가열 실험은 고온 가열시 epoxy의 유동 문제를 극복할 새로운 방법의 개발이 필요하다.

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