• International conference on construction engineering and project management
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• 2009.05a
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• pp.732-737
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• 2009

Due to various project delivery methods and the complexity of construction projects in the construction industry, developing the framework of construction management for critical, highly complex projects in the construction industry has become problematic. Currently, a set of construction manuals play a pivotal role in planning and managing construction projects as subcontractors try to complete their scope of work according to the instructions of a general contractor. It is challenging for general contractors to write a construction management procedure manual to cover various types of project delivery methods and construction projects. In construction, the construction procedure manuals describe specific actions to be taken through the project. In reality a few contactors own such manuals and their construction schedules include more construction operation activities. Thus, it is hard to estimate the workload and productivity of construction managers because the manual and the schedule do not present the amount of management efforts required to complete a project. This paper proposes a framework to present construction management tasks according to project delivery methods which can be applied to various construction projects. Actions for management tasks were mapped and were integrated with construction activities throughout the project life cycle. The framework can then be used to give specific instructions to project participants, collect management actions, and replicate management actions throughout the project life cycle. The framework can also be can used to visualize complete construction project to analyze and manage construction management activities in each phase of a project in order to enhance productivity and efficiency. The studies of existing construction manuals were carried out to identify construction managers' responsibilities. An artificial intelligence program, CLIPS (C-Language Integrated Production System) was used to search for appropriate actions for impending tasks from a set of predefined actions to be performed for a given situation. The framework would significantly help construction managers to understand interrelations among management tasks or actions within a project. Furthermore, the framework can be embedded into Building Information Modeling (BIM) or Facility Management Systems (FMS) so that designers and constructors would execute constructability review before construction begins.

• Proceedings of the Korea Society for Simulation Conference
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• 1997.04a
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• pp.65-65
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• 1997

가입자가 B-ISDN(Broadband Integrated Services Digital Network) 서비스에 대한 shb은 수준의 품질 및 안정적인 서비스 제공을 요구함에 따라, 이러한 서비스를 제공하기 위한 ATM (Asynchronous Transfer Mode) 교환기에 대한 신뢰성 설계의 중요성은 증가하 고 있다. 교환기의 중요한 신뢰성 성능 척도 중의 하나인 연결 절단율 (Cutoff connection rate)은 총 연결시간 동안 절단된 연결수로 정의되며, 연결 절단은 호 설정 (Call setup) 단 계를 지나 서비스 중인 연결이 사용자의 요구가 아닌 시스템의 고장으로 종료될 때 발생한 다. 연결 절단율 추정 문제는 기존의 신뢰도 또는 가용도 예측을 위한 시뮬레이션과는 달리 시스템 구성 유니트들의 고장율, 수리율, 그리고 요구된 연결의 트래픽 특성 부분이 혼합된 문제이다. 따라서, B-ISDN 서비스의 중요한 특징인 다양한 트래픽 특성과 시스템의 구성 (Configuration)을 고려하여 연결 절단율을 해석적인 방법을 통하여 추정하는 데네는 어려 움이 있으며 시뮬레이션에 의한 방법이 적절하다. 본 고에서는 B-ISDN 서비스의 트래픽 특 성과 ATM 교환기의 시스템 구성 및 신뢰도 데이터로부터 시스템의 연결 절단율을 추정하 기 위한 시뮬레이터의 기능 및 구조, 시뮬레이션 수행 결과 등을 제시한다. 시뮬레이터는 AweSim 시뮬레이션과 CUser Written Code를 사용하여 개발하였다. 시뮬레이터의 구성 모듈은 크게 호 도착 모듈, 연결 제어 및 자원 할당 모듈, 유니트 고장 및 수리 모듈, 통계 량 수집 모듈 등으로 구성된다. 개발된 시뮬레이터는 B-ISDN 트래픽 파라메터와 연결 절단 율의 상호 관계 규명 및 시스템 설계 대안 (Design alternatives)에 대한 비교/평가에 활용 된다., 수중생물의 경우는 특히 수온, 수량 영양원등이다.(중략). 본 연구의 접근방법으로는 ASRS의 개념적인 Reference Model을 수립하고 이 Reference Model에 대한 Formal Model로 DEVS(Discrete Event System Specification)을 이용하여 시스템을 Modeling하였다. 이의 Computer Simulation을 위하여 DEVS형식론 환경에서의 Simulation Language인 DEVSim ++ⓒ를 이용하여 시스템을 구현하였다.. 실형 결과로는 먼저 선형 상미분방정식의 예로 mass-damper-spring system, 비선형 상미분방정식의 예로는 van der Pol 방정식, 연립 상미분방정식의 예로는 mixing tank problem 등을 보였으며, 그의 공학에서 일어나는 여러 가지 문제들도 다루었다.화물에 대한 방어력이 증가되어 나타난 결과로 여겨지며, 또한 혈청중의 ALT, ALP 및 LDH활성을 유의성있게 감소시키므로서 감잎 phenolic compounds가 에탄올에 의한 간세포 손상에 대한 해독 및 보호작용이 있는 것으로 사료된다.반적으로 홍삼 제조시 내공의 발생은 제조공정에서 나타나는 경우가 많으며, 내백의 경우는 홍삼으로 가공되면서 발생하는 경우가 있고, 인삼이 성장될 때 부분적인 영양상태의 불충분이나 기후 등에 따른 영향을 받을 수 있기 때문에 앞으로 이에 대한 많은 연구가 이루어져야할 것으로 판단된다.태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(minimal $X^{0}$ elements)로 가정한다. 즉, [+wh] 의미의 겹의문사는 동일한 구성요 소를 지닌 병렬적 합성어([$[W1]_{XO-}$ $[W1]_{XO}$ ]$_{XO}$

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.655-663
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• 2016

Increasing green house gas and it consequent climate change problems are discussed as a global issue. Accordingly, future local green house gas emission will increase up to 40% of the entire local green house gas emission and therefore, efforts to reduce the emission in construction industry is urgently required. Therefore, in this study, heating energy demand was analyzed by using the EnergyPlus simulation according to wood material finishes configuration. EnergyPlus has the entry for a variety of buildings and heating, ventilation, air conditioning (HAVC) system components, in particular buildings, air conditioning systems, and performs simultaneous integrated calculated through the feedback between the heat source unit, a verification program according to the ASHRAE Standard 140-2007 to be. The climate data for the simulation we used the data IWEC in Incheon and Gwangju provided by EnergyPlus. The analysis of simulation model was farm and fishing house standard design drawings: 2012, presented at the Korea Rural Community Corporation. The results of simulation of central region and southern region were effected by wood products of simulation model into the interior finish, exterior finish, windows, wooden structure. Also, it was confirmed that the reduced heating energy demand.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.88-95
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• 2018

Maintainability indicates how easily a system can be restored to the normal state when a system failure occurs. Systems developed to have high maintainability can be competitive due to reduced maintenance time, workforce and resources. Quantification of the maintainability is possible in many ways, but only after prototype production or with historical data. As such, the graph theory and 3D model data have been used, but there are limitations in management efficiency and early use. To solve this problem, we studied the maintainability index of weapon systems using SysML-based modeling and simulation technique. A SysML structure diagram was generated to simultaneously model the system design and maintainability of system components by reflecting the maintainability attributes acquired from the system engineering tool. Then, a SysML parametric diagram was created to quantify the maintainability through simulation linked with MATLAB. As a result, an integrated model to account for system design and maintainability simultaneously has been presented. The model can be used from early design stages to identify components with low maintainability index. The design of such components can be changed to improve maintainability and thus to reduce the risks of cost overruns and time delays due to belated design changes.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.6
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• pp.1-7
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• 2012

Due to the increasing demand of network convergence, in future, hybrid/integrated satellite and terrestrial systems will play an important role. In that case, compatibilities between the satellite and terrestrial systems are very important for efficiency of the systems. 3GPP Long Term Evolution (LTE) is one of the 4G system. Therefore, in this paper, we introduce the design of interleaver for mobile satellite system based 3GPP LTE specification. The 4G system including the LTE specification adopted adaptive modulation and coding (AMC) schemes for efficient usage of resources, and the updating interval of resource allocation is an order of msec. However, because of the long round trip delay of satellite systems, we cannot employ the same AMC scheme specified for the terrestrial system, and thus it cannot effectively counteract to short term fadings. Therefore, in order to overcome these problems, we propose an interleaver scheme combined with AMC. We present the interleaver design results considering mobile satellite system based on the LTE and analyze the simulation results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.2
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• pp.107-114
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• 2007

This paper focuses on the performance evaluation of various control allocation methods applied on DURUMI-II UAV system. In order to implement control allocation scheme to aircraft control system, control system can be designed through two step design procedure. The first step is to design a baseline control system for an aircraft without consideration of control surface failure. The second step is to design a control allocator that maps the total control command on the individual control surfaces. In this paper, several control allocation methods such as Psuedo-Inverse CA method, Direct CA method, and Optimization CA method are implemented and integrated to the baseline flight control system of DURUMI-II UAV. The performance of these control allocation methods is evaluated by nonlinear simulation under the flight scenario of control surface failure.

• Journal of the Korean Society of Systems Engineering
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• v.9 no.1
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• pp.33-45
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• 2013

Systems Engineering Approach was applied to the development of operator-support core management system based on the on-site operation experience and document of core management procedures, which is for enhancing operability and safety in PHWR (Pressurized Heavy Water Reactor) operation. The dissertation and definition of the system were given on th basis of investigating and analyzing the core management procedures. Fuel management, detector calibration, safety management, core power distribution monitoring, and integrated data management were defined as main user's requirements. From the requirements, 11 upper functional requirements were extracted by considering the on-site operation experience and investigating documents of core management procedures. Detailed requirements of the system which were produced by analyzing the upper functional requirements were identified by interviewing members who have responsibility of the core management procedures, which were written in SRS (Software Requirement Specification) document by using IEEE 830 template. The system was designed on the basis of the SRS and analysis in terms of nuclear engineering, and then tested by simulation using on-site data as a example. A model of core power monitoring related to the core management was suggested and a standard process for the core management was also suggested. And extraction, analysis, and documentation of the requirements were suggested as a case in terms of systems engineering.

• The Journal of Information Systems
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• v.26 no.4
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• pp.63-85
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• 2017

Purpose Recently, much attention in building smart factory has dramatically increased with an emergence of the Industry 4.0. As we noted a connectivity gap between main concerns of MIS and the automated manufacturing systems such as POP and MES, it is recommended that CPS (Cyber-Physical System) can be an important building block for the smart factory and enrich the depth of MIS knowledge. Therefore, first, this study attempted to identify the connectivity gap between the traditional field of MIS (ERP, SCM, CRM, etc.) and the automated manufacturing systems, and then recommended CPS as a technical bridge to fill the gap. Secondly, we studied concepts and research trend of CPS that is believed to be a virtual mechanism to manage manufacturing systems in an integrated manner. Finally, we suggested research and educational opportunities in MIS based on the CPS perspectives. Design/methodology/approach Since this paper introduced relatively new idea of CPS originally discussed in the field of engineering, traditional MIS research method such as survey and experiment may not fit well. Therefore this research collected technical cases through literature survey in engineering fields, video clips from Youtube, and field references from various ICT Exhibitions and Conventions. Then we analyzed and reorganized them to highlight the necessity of CPS and draw some insight to share with MIS academia. Findings This paper introduced CPS to bridge the connectivity gap between the traditional MIS and automated manufacturing system (smart factory), a concern far away from the MIS academia. Further, this paper suggested future research subjects of MIS such as developing software to share big production data and systems to support manufacturing decisions, and innovating MIS curricula including smart and intelligent manufacturing technology within the context of traditional enterprise systems.

• Progress in Superconductivity and Cryogenics
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• v.18 no.4
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• pp.25-29
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• 2016

The high temperature superconducting (HTS) contra-rotating propulsion (CRP) systems comprise two coaxial propellers sited on behind the other and rotate in opposite directions. They have the hydrodynamic advantage of recovering the slipstream rotational energy which would otherwise be lost to a conventional single-screw system. However, the cooling systems used for HTS CRP system need a high cooling power enough to maintain a low temperature of 2G HTS material operating at liquid neon (LNe) temperature (24.5 - 27 K). In this paper, a single thermo-syphon cooling approach using a Gifford-McMahon (G-M) cryo-cooler is presented. First, an optimal thermal design of a 1.5 MW HTS motor was conducted varying to different types of commercial 2G HTS tapes. Then, a mono-cryogenic cooling system for an integration of two 1.5 MW HTS motors will be designed and analyzed. Finally, the 3D finite element analysis (FEA) simulation of thermal characteristics was also performed.

• Korean System Dynamics Review
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• v.15 no.4
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• pp.5-28
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• 2014

Derivatives can be easily bought by those companies that need to hedge foreign currency debt or foreign currency assets through the financial market, considering their exchange rate exposure from international trade. The derivatives market has been growing rapidly due to the needs for investment and hedging. To manage foreign exchange risk, companies hedge risks through financial derivatives. According to our study, hedging is an effective way to mitigate the impact of exposure to exchange risk, as long as companies are only hedging underlying assets. Yet, covetous attitude toward the profit from derivatives and unexpected changes in exchange rate can cause problems for companies. This study analyzed the structural risks of derivatives with analysis of system dynamics. In particular, many companies suffered substantial loss due to KIKO during the economic crisis. We explained the problem therein through dynamic analysis. In addition, we revealed the structural problem that could cause a sudden spike in losses through simulations.