• 제목/요약/키워드: Independent Operation

검색결과 865건 처리시간 0.034초

외기보상제어 적용에 따른 지열 히트펌프 시스템의 에너지 효율 향상에 관한 연구 (A Study on the Energy Efficiency of a Geothermal Heat Pump System in use the Outdoor Reset Control Application)

  • 정영주;김효준;이용호;황정하;조영흠
    • 한국태양에너지학회 논문집
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    • 제35권1호
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    • pp.45-52
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    • 2015
  • The government is fostering a renewable energy industry as an alternative to handle the energy crisis. Among the renewable energy systems available, geothermal energy is being highlighted as being highly efficient and safely operable without the effect of outdoor air. Accordingly, a study on the geothermal heat pump is in progress in various worldwide perspective. However, Geothermal energy is only in charge of part load of the building due to the high initial installation cost in korea. Moreover, its efficiency is reduced due to the use of independent existing heat sources. In this study, after selecting the building containing the actual installed geothermal heat pump, the use of excellent geothermal heat pump systems was maximized in terms of the energy efficiency. The objective of this study is to show the operation method of geothermal heat pump system to improve energy efficiency through the TRNSYS simulation. This paper proposed operation methods of geothermal heat pump control according to outdoor air temperature. The result of this study is that existing operation method had some problems and if offered improvement is applied to real condition, energy consumption would be decreased.

NONLINEAR CONTROL FOR CORE POWER OF PRESSURIZED WATER NUCLEAR REACTORS USING CONSTANT AXIAL OFFSET STRATEGY

  • ANSARIFAR, GHOLAM REZA;SAADATZI, SAEED
    • Nuclear Engineering and Technology
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    • 제47권7호
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    • pp.838-848
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    • 2015
  • One of the most important operations in nuclear power plants is load following, in which an imbalance of axial power distribution induces xenon oscillations. These oscillations must be maintained within acceptable limits otherwise the nuclear power plant could become unstable. Therefore, bounded xenon oscillation is considered to be a constraint for the load following operation. In this paper, the design of a sliding mode control (SMC), which is a robust nonlinear controller, is presented.SMCis ameansto control pressurized water nuclear reactor (PWR) power for the load following operation problem in a way that ensures xenon oscillations are kept bounded within acceptable limits. The proposed controller uses constant axial offset (AO) strategy to ensure xenon oscillations remain bounded. The constant AO is a robust state constraint for the load following problem. The reactor core is simulated based on the two-point nuclear reactor model with a three delayed neutron groups. The stability analysis is given by means of the Lyapunov approach, thus the control system is guaranteed to be stable within a large range. The employed method is easy to implement in practical applications and moreover, the SMC exhibits the desired dynamic properties during the entire output-tracking process independent of perturbations. Simulation results are presented to demonstrate the effectiveness of the proposed controller in terms of performance, robustness, and stability. Results show that the proposed controller for the load following operation is so effective that the xenon oscillations are kept bounded in the given region.

ESS 안전 운영을 위한 독립형 PMS 개발 (Developed Stand alone PMS for ESS Safety Operation)

  • 오홍근;김철원
    • 한국전자통신학회논문지
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    • 제14권2호
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    • pp.351-360
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    • 2019
  • 최근 정부의 에너지 정책에 힘입어 ESS(: Energy Storage System) 설비가 증가하고 있으며 이로 인해 화재 폭발 등 다양한 사건사고가 발생하고 있다. 현재 ESS는 PMS(: Power Management System) 포함하여 모든 시스템이 현장에 설치되어있는 통합형 ESS로 구축되어 있다. 이 시스템은 사고 발생 시 산화되어 데이터의 부재 가능성이 매우 높을 뿐만 아니라 외부에 존재하는 관리자가 사고 발생 시 신속하게 대응할 방법이 없는 상황이다. 이에 본 논문에서는 별도의 WAS 및 데이터 스토리지 구축을 통해 기존 시스템에서의 주요 기능을 분리하여 외부에서 EMS(: Energy Management system) 운용이 가능함과 동시에 사고 발생 시 원인 및 신속한 대응이 가능한 독립형 PMS 개발을 제안하고자 한다.

병원 내 의학도서관 운영현황 분석을 통한 활성화 방안에 관한 연구 (A Study on the Activation Plan through the Analysis of the Operation Status of the Medical Library in the Hospital)

  • 노영희;신영지
    • 한국도서관정보학회지
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    • 제50권2호
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    • pp.61-96
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    • 2019
  • 본 연구에서는 병원 내 의학도서관을 대상으로 서비스 대상, 장서, 시설 및 환경, 직원, 서비스 등에 대한 전반적인 운영현황을 조사하고, 해당 도서관 사서들을 대상으로 도서관의 수요조사 및 인식조사를 실시하여, 향후 병원 내 의학도서관의 활성화 방안을 제안하고자 하였다. 그 결과, 첫째, 병원 내 의학도서관이 본연의 역할을 수행하고 도서관 서비스의 질을 높임으로써 도서관의 위상을 높이려면, 조직상 독립부서로 분리되어야 한다. 둘째, 병원 내 의학도서관에 대한 장서, 규모, 인력에 대한 법적 기준 제정이 필요하다. 셋째, 체계적인 병원 내 의학도서관 운영을 위해 도서관 고유업무와 행정업무가 구별될 수 있도록 전문직 사서의 지원과 인력 충원이 이루어져야 할 것이다. 넷째, 병원 내 의학도서관 활성화를 위해 국가적 차원의 예산 지원, 사서의 전문화 교육, 운영 가이드라인 개발, 타 도서관과의 네트워크 활성화 등의 정책이 필요한 것으로 보인다.

Postoperative Complications and Their Risk Factors of Completion Total Gastrectomy for Remnant Gastric Cancer Following an Initial Gastrectomy for Cancer

  • Park, Sin Hye;Eom, Sang Soo;Eom, Bang Wool;Yoon, Hong Man;Kim, Young-Woo;Ryu, Keun Won
    • Journal of Gastric Cancer
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    • 제22권3호
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    • pp.210-219
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    • 2022
  • Purpose: Completion total gastrectomy (CTG) for remnant gastric cancer (RGC) is a technically demanding procedure and associated with increased morbidity. The present study aimed to evaluate postoperative complications and their risk factors following surgery for RGC after initial partial gastrectomy due to gastric cancer excluding peptic ulcer. Materials and Methods: We retrospectively reviewed the data of 107 patients who had previously undergone an initial gastric cancer surgery and subsequently underwent CTG for RGC between March 2002 and December 2020. The postoperative complications were graded using the Clavien-Dindo classification. Logistic regression analyses were used to determine the risk factors for complications. Results: Postoperative complications occurred in 34.6% (37/107) of the patients. Intra-abdominal abscess was the most common complication. The significant risk factors for overall complications were multi-visceral resections, longer operation time, and high estimated blood loss in the univariate analysis. The independent risk factors were multi-visceral resection (odds ratio [OR], 2.832; 95% confidence interval [CI], 1.094-7.333; P=0.032) and longer operation time (OR, 1.005; 95% CI, 1.001-1.011; P=0.036) in the multivariate analysis. Previous reconstruction type, minimally invasive approach, and current stage were not associated with the overall complications. Conclusions: Multi-visceral resection and long operation time were significant risk factors for the occurrence of complications following CTG rather than the RGC stage or surgical approach. When multi-visceral resection is required, a more meticulous surgical procedure is warranted to improve the postoperative complications during CTG for RGC after an initial gastric cancer surgery.

프랜차이즈 모기업 핵심역량 자원이 가맹점 관계결속과 재계약의도에 미치는 영향 (Effects of Core Competence and Resource Sharing on the Relational Bond among Franchisees and on Re-contract Intention in the Franchising Parent Companies)

  • 허영욱;주말찬
    • 유통과학연구
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    • 제12권4호
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    • pp.11-22
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    • 2014
  • Purpose - The domestic franchise industry has made significant contributions to industry such as investment, employment, and community economy development, facilitating growth potential. The franchise industry provides management knowhow transfer between parent companies and franchisees as per contracts addressing use of business signs, franchisees' independent position, franchisor support, and royalties to be paid to the franchisors. However, many franchisors lack management knowhow and provide insufficient support because of poor control of franchisees and not having a systematic approach to support. This results in dissatisfied franchisees and failure to establish long-term relationships. Few studies have examined relational commitment and/or re-contract intention by support resources between franchisors and franchisees, despite a considerable output of theories and studies of the growth of the franchise industry. The purpose of this study, therefore, was to examine the effects of the ability to provide resources on relational commitments and re-contract intention, and to suggest causal relationships and implications. Research design, data, and methodology - The subject was domestic franchisors registered with the Association of Franchise with more than 50 franchisees. Franchisees under contract for 2 years and considering re-contract of their franchise 2 years later were used. The subjects totaled 300 franchisees in Seoul. A questionnaire survey was used to investigate the subject of franchisees' concessions during the 10 days from November 21, 2013 to November 30, 2013. After excluding 16 surveys with poor answers, 284 responses were finally used. Four areas and 44 questions were used. A nominal scale was used for four common characteristics questions including gender, ages, educational background, and franchise managing time. Questions regarding ability, relational commitment, and re-contract intention made use of a Likert 5-point scale. Data coding and data cleaning were used. SPSS 18.0 was used as follows. First, frequency analysis was done to investigate demographic characteristics. Second, exploratory factor analysis was done to verify validity of testing tools, and Cronbach's α coefficient was used to verify reliability. Third, correlation analysis and multiple regression analysis were done. An exploratory factor analysis was done to verify validity of concepts. A correlation analysis was done to test relationships between the variables, and multiple regression analysis was done to verify franchisor's ability, franchisees' relational commitment, and re-contract intention. Results - The following were the outcomes. First, store operation management, finance operation management, and human resource management affected the calculated bond. Second, store operation management and finance operation management affected the emotional bond. Third, store operation management, finance operation management, human resource management, and marketing management affected the prescriptive bond. Fourth, calculated bond and prescriptive bond had an effect on re-contract intention. Conclusions - As stated above, in franchise management, parent companies' offer and instruction of core competence to their franchisees as an information resource could improve the relational bond by helping them grow together through the resource sharing. Consequently, core competence factors were promoting factors that could improve franchisees' re-contract intention for a long time.

4-Channel Patch Array Antennas for Home Network System

  • Min Kyeong-Sik;Kim Dong-Jin
    • Journal of electromagnetic engineering and science
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    • 제5권3호
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    • pp.122-125
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    • 2005
  • This paper describes a design of a miniature patch antenna and its 4-channle array for 5.25 GHz wireless LAN band. Each patch element is designed for the low mutual coupling between each element and for the small size of the array antenna. The size of the each element is $7 mm{\times}14.5 mm{\times}5.6 mm$ and it satisfy IEEE 802.11a frequency band. It is arrayed for independent 4-channel operation. The total size of the array antenna is $35.6 mm{\times}52.5 mm{\times}5.6 mm$. The measured reflection coefficients and the radiation patterns of the fabricated antennas show the reasonable agreements with prediction.

장애인과 노약자를 위한 지능형 재활 로봇 시스템(KARES) (Intelligent rehabilitation robotic system for the handicapped and the elderly-KARES)

  • 송원경;김종명;윤용산;변증남
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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    • pp.1541-1544
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    • 1997
  • The rehailitation robot, one of the service robot, is the important area in the service automation. In the paper, we describe the overall configuration of KARES(KAIST Rehabilitation Engineering System), which is an intellingent rehabilitaion robotic system designed to assist the independent livelihood of the handicapped and the eldrly. KARES consists of the 6 degree of freedom robot arm mounted on a wheelchair, the controller ofr the arm, sensors to perceive environment, and user interface. Basic desired hobs in KARES are gripping the target object and moving it to the user's face for eating, drinking, or cooperation work wiht the mouth. Currently, the manual operation of the arm is available for gripping to target objects. The autonomous functionality will be ginven for the facilities of the human operator.

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Decentralized Motion Control of Mobile Manipulator

  • Phan, Tan-Tung;Suh, Jin-Ho;Kim, Sang-Bong
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.1841-1846
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    • 2003
  • The mobile platform-manipulator discussed in this paper is a three link manipulator mounted on a mobile platform. This mobile manipulator is used for welding operation and it is able to operate in a narrow space. The task of the torch, which is mounted at the end effector of the manipulator, is to track along the seam line and the task of the mobile platform is to move the origin point of the manipulator in order to go away from the singularity of the manipulator’s configuration. In this paper, the path planning for the motion of two subsystems (i.e., the manipulator and the mobile platform) was presented by the decentralized control method. Two controllers for the mobile platform and the manipulator were designed, and the relationship between the independent controllers is its state information. The simulation results are also presented to demonstrate the effectiveness of the control method.

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Optimization of Process Variables for the Soda Pulping of Carpolobia Lutea (Polygalaceae) G. Don

  • Ogunsile, B.O.;Uba, F.I.
    • 대한화학회지
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    • 제56권2호
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    • pp.257-263
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    • 2012
  • The selection of suitable delignification conditions and optimization of process variables is crucial to the successful operation of chemical pulping processes. Soda pulping of Carpolobia lutea was investigated, as an alternative raw material for pulp and paper production. The process was optimized under the influence of three operational variables, namely, temperature, time and concentration of cooking liquor. Equations derived using a second - order polynomial design predicted the pulp yield and lignin dissolution with errors less than 8% and 11% respectively. The maximum variations in the pulp yield using a second order factorial design was caused by changes in both time and alkali concentration. Optimum pulp yield of 43.87% was obtained at low values of the process variables. The selectivity of lignin dissolution was independent of the working conditions, allowing quantitative estimations to be established between the pulp yield and residual lignin content within the range studied.