• Title/Summary/Keyword: large-scale systems

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A Study on the Impact of the PMS Quality on Performance in Information Systems Project (IS프로젝트에서 PMS 품질이 성과에 미치는 영향에 대한 연구)

  • Jeong, Cheonsu;Ahn, Hyunchul
    • Knowledge Management Research
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    • v.13 no.3
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    • pp.79-103
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    • 2012
  • Recently because the IS development project is large scale and complicated, the necessity of tools that can manage effectively smooth communications and the harmonized project between the interested parties is exposed. According to this fact, many companies are investing enough to the PMS (Project Management System) for the sake of the systematic management of the IS development project, and also this PMS is emerging as one of the indispensable tools for the successful IS development project by casting off from a auxiliary means for the past project management. However, as had been expected, whether the introduction of the PMS is possible to facilitate communications within a project team, and a main motivation that can derive individual performance and organizational performance that participated in the IS development project is induced or not are not verified still empirically and apparently. With respect to this, a survey was conducted to examine how PMS quality affected user satisfaction, communication, individual performance and project performance. The effects of the data gathered were verified by structural equation model analysis.

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Token-Bucket-based Performance Control Techniques for Large-Scale Shared Storage Systems (대용량 공유 스토리지 시스템을 위한 토큰 버킷기반 성능 제어 기법)

  • Nam Young-Jin;Park Chan-Ik
    • The KIPS Transactions:PartA
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    • v.12A no.7 s.97
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    • pp.605-612
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    • 2005
  • With the increase in I/O performance and capacity, it becomes commonplace that storage systems are shared by multiple storage users. This paper proposes an efficient token-bucket-based performance control technique for the shared storage that can statistically guarantee demanded storage performance from different users. It also verifies the operational characteristics and performance of the proposed scheme under various types of I/O workloads.

A Design of Power Management and Control Systems Using Digital Protective Relays (디지털보호계전기를 활용한 전력감시제어시스템 설계)

  • Lee, Sung-Hwan;Ahn, Ihn-Seok
    • Proceedings of the KIEE Conference
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    • 2000.07a
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    • pp.191-193
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    • 2000
  • In this paper, being different from traditional methods, we design digital protective relay which can be applied to power management and control systems of not only small and medium but also a large scale plants. The digital protective relay was designed with DSP CPU(TMS320C31) to protect and measure more quickly and precisely. We will present test result which it performed according to the standards of Korea Electrical Manufactures Cooperative to prove the faculties of digital protective relay. The test result on the basis of KEMC1120 and IEC60255, show that the operation time error of the digital motor protection relay is improved within ${\pm}5%$.

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An IPLAN-based Program for Technical Assessment of New-connected Facilities (IPLAN을 이용한 전력설비의 계통접속 기술검토 프로그램 개발)

  • Ryu, Heon-Su;Bae, Joo-Cheon
    • Proceedings of the KIEE Conference
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    • 2005.11b
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    • pp.220-222
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    • 2005
  • When a large-scale load or a new generator is connected to power systems, KPX assesses the effect of the connection on power systems to keep security and reliability standards. As the number of connection requests has been increased, KPX is spending much time for technical assessments of the requests. This paper developed an automatic assessment program to reduce analysis time and enhance simulation accuracy. The program is based on IPLAN and. can be applied to both load and generator network connection requests.

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A study on power system stabilizer using output feedback adaptive variable structure control

  • Shin, Jin-Ho;Jeong, Il-Kwon;Choi, Changkyu;Lee, Ju-Jang
    • 제어로봇시스템학회:학술대회논문집
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    • 1994.10a
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    • pp.177-182
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    • 1994
  • In this paper, an output feedback adaptive variable structure control scheme is presented for stabilization of large scale power systems. An additional input signal which is called a power system stabilizer(PSS) is needed to improve the stability of a power system and to maintain the synchronization of generators. The proposed PSS scheme does not require a priori knowledge of uncertainty bounds. It is guaranteed that the closed-loop system is globally uniformly ultimately bounded by the Lyapunov stability theory. Simulation results for a multimachine power system are given to show the feasibility of the proposed scheme and the superiority of the proposed PSS in comparison with the conventional lead-lag PSS of PID-type.

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A New Stabilization Method for a Class of Interconnected Systems By Using Local State Feedback (상태궤환을 이용한 상호 결합된 시스템의 새로운 비집중 안정화 방법)

  • Chae, Seog;Bien, Zeungnam
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.10
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    • pp.1498-1506
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    • 1989
  • A new stabilization scheme is proposed in which the local state feedback is utilized in each decentralized controller for large-scale interconnected systems. In the proposed scheme, the controller is designed in two steps. First, the feedback gain of each decentralized controller is temporarily chosen so that the eigenvalues of each isolated subsystem are placed at the desired locations in the complex plane. Secondly, the feedback gain of each controller is compensated so that the time derivative of the Lyapunov function candidate for the overall closed-loop system should be negative. A sufficient condition which assures the global system to stable is given.

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Standard Classifications and Project Numbering System for Integrated Construction Management of Modernized Korean Housing (Hanok) (신한옥 건설통합정보화를 위한 표준정보분류 및 사업번호체계)

  • Jung, Young-Soo;Kim, Woo-Joong;Ha, Ji-Won
    • Korean Journal of Computational Design and Engineering
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    • v.17 no.4
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    • pp.225-233
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    • 2012
  • A comprehensive research effort in order to develop and disseminate modernized Korean housing (Hanok) has recently been initiated by Korean government. This large scale research project encompasses a wide spectrum of housing development including public policy, architectural plans, modules, construction materials and methods, prefabricated assemblies, automated production, construction management, and advanced information systems. For the purpose of integrating and automating the whole processes from an industry perspective, it is of great importance to develop a standard classification system and project numbering system (PNS) for the modernized Korean housing. This paper focuses on the standard classification systems and PNS for cost and schedule control. The distinct characteristics and managerial requirements were explored and embedded into the proposed classifications for modernized Hanok.

An Analysis of Fuzzy Survey Data Based on the Maximum Entropy Principle (최대 엔트로피 분포를 이용한 퍼지 관측데이터의 분석법에 관한 연구)

  • 유재휘;유동일
    • Journal of the Korea Society of Computer and Information
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    • v.3 no.2
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    • pp.131-138
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    • 1998
  • In usual statistical data analysis, we describe statistical data by exact values. However, in modem complex and large-scale systems, it is difficult to treat the systems using only exact data. In this paper, we define these data as fuzzy data(ie. Linguistic variable applied to make the member-ship function.) and Propose a new method to get an analysis of fuzzy survey data based on the maximum entropy Principle. Also, we propose a new method of discrimination by measuring distance between a distribution of the stable state and estimated distribution of the present state using the Kullback - Leibler information. Furthermore, we investigate the validity of our method by computer simulations under realistic situations.

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Effect of Load Condition on Turning Performance of a VLCC in Adverse Weather Conditions

  • Zaky, Mochammad;Yasukawa, Hironori
    • Journal of Advanced Research in Ocean Engineering
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    • v.4 no.2
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    • pp.53-65
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    • 2018
  • The load condition significantly influences ship maneuverability in calm water. In this research, the effect of the load condition on turning performance of a very large crude oil carrier (VLCC) sailing in adverse weather conditions is investigated by an MMG-based maneuvering simulation method. The relative drift direction of the ship in turning to the wave direction is $20^{\circ}-30^{\circ}$ in ballast load condition (NB) and full load condition (DF) with a rudder angle $35^{\circ}$ and almost constant for any wind (wave) directions. The drifting displacement in turning under NB becomes larger than that under DF at the same environmental condition. Advance $A_d$ and tactical diameter $D_t$ become significantly small with an increasing Beaufort scale in head wind and waves when approaching, although $A_d$ and $D_t$ are almost constant in following wind and waves. In beam wind and waves, the tendency depends on the plus and minus of the rudder angle.

ORDER REDUCTION OF LINEAR SYSTEMS BY MODAL METHOD (모달 방법을 사용한 선형시스템의 오더. 리덕손)

  • Lee, Kun-Yong
    • Proceedings of the KIEE Conference
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    • 1984.07a
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    • pp.84-85
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    • 1984
  • The accurate description of many physical processes leads to high number of different equations which are very difficult to handle for simulation or control purposes. The reduction of high-order, linear, time-invariant systems to lower-order ones has been investigated by many researchers. In this paper, a model technique among these methods is used. This technique has been developed here as if it were extensions of Davison's original method (1), its modification having been made to provide, among other things, steady state agreement between the original large-scale and reduced-order model. The advantage of the modal analysis approach is that only matrix operations have to be executed. Here, it is very simple to obtain a reduced model. An example of illustration is shown using the model method.

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