• Architectural research
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• 제4권1호
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• pp.53-61
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• 2002

The typical Critical Path Method (CPM) leaves it to the construction managers to overcome two problems in developing networks. First, the construction manager needs to prepare information on the type of activities and their precedence relations in order to develop a network schedule. Second, he or she can include space information into the network schedule such as the locations where the activities take place, only with difficulty. These two problems make it difficult for an inexperienced person to create a network. The purpose of this paper is to provide construction managers with set equations of creating a network schedule for multiunit projects. A space-resource combined network creation are presented in this paper, which includes equations for generating a list of required activities, their precedence relations, and information on their location. Information on the space (location) and the resource is the required data for this method. Based on this information, this method divides a project into a number of activities so that each activity contains the information on the location where the activity takes place and the principal resource required for that activity. Precedence relations are then obtained from the sequence of space and resource. This method has the potential to reduce human efforts in scheduling activities.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.311-313
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• 2012

Many efforts have been made and many tools have been developed in order to manage construction projects by a smart device such as a smart phone and smart pad. This research proposed a method to manage construction schedules via a smart device using Flash. The interactive and graphic property of Flash enables a field manager to manage schedules easily and efficiently. A prototype was implemented by Adobe Flex Builder, and it applied a sample network in a smart pad. Further studies would develop network diagrams such as CPM(Critical Path Method).

• 한국건축시공학회지
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• 제10권2호
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• pp.51-57
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• 2010

건설공사의 일정관리는 주어진 기간 내에 프로젝트를 완수하기 위한 중요한 수단이다. 액티비티의 수가 많아지고 복잡한 선후행 관계가 형성될수록 일정관리 소프트웨어를 활용해야 하는 필요성이 증대되고 있다. 또한 정보통신기술이 발달하면서 웹기반의 프로젝트관리 기술과 도구도 발전하고 있고 다수의 프로그램도 개발되어 있다. 본 연구는 웹 기반에서 일정관리 도구를 개발하기 위해 상호작용성이 우수한 플래시를 이용하는 방법을 제안하였다. 제안된 방법을 구현하기 위해 플래시와 액션스크립트로 프로토타입을 작성하였고 웹 화면에서 공정표를 표현하여 적용성을 검토하였다.

• 대한교통학회지
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• 제8권2호
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• pp.67-75
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• 1990

This paper treats the problem to schedule for trains with how transit priority so as to maximizing the number that can be sent during given time periods without interfering with the fixed schedule for train with high transit priority in a track. We transform the this problem into Time Expanded Network without traverse time through application of Ford and Fulkerson Model and construct the Enumeration Algorithm for solutions using TENET Generator (TENETGEN). Finally, we compare our algorithm with Dinic's Maximal-Flow Algorithm and examine the avaliability of our procedures in personal computer.

• 대한산업공학회지
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• 제3권2호
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• pp.93-97
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• 1977

PERT/CPM type scheduling systems use a network to graphically portray the interrelationship among the activities of a project. This network representation of the project schedule shows all the precedence relationship regarding the order in which tasks must be performed. In this paper an algorithm is presented that changes the network configurations without violating precedence relationship of the original network.

• 제어로봇시스템학회논문지
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• 제11권2호
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• pp.167-174
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• 2005

This paper experimentally validates the efficacy of scheduling method that satisfies the performance requirement of periodic data in the Foundation Fieldbus. The scheduling method allocates periodic data traffic to a bandwidth-limited fieldbus medium. The scheduling method generates schedule list that records schedule starting time and schedule period of each periodic data. This study developed an experimental model of a Foundation Fieldbus network system. Using the experimental model, this study showed that the scheduling method can be easily implemented in a practical Foundation Fieldbus network system. The results obtained from the experimental evaluation showed that the scheduling method restricts the delay of periodic data to a pre-specified bound.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권4호
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• pp.1359-1375
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• 2015

Energy efficiency is critical for Wireless Sensor Networks (WSNs) since sensor nodes usually have very limited energy supply from battery. Sleep scheduling and nodes cooperation are two of the most efficient methods to achieve energy conservation in WSNs. In this paper, we propose an adaptive energy optimization approach for target tracking applications, called Energy-Efficient Node Coordination (EENC), which is based on the grid structure. EENC provides an unambiguous calculation and analysis for optimal the nodes cooperation theoretically. In EENC, the sleep schedule of sensor nodes is locally synchronized and globally unsynchronized. Locally in each grid, the sleep schedule of all nodes is synchronized by the grid head, while globally the sleep schedule of each grid is independent and is determined by the proposed scheme. For dynamic sleep scheduling in tracking state we propose a multi-level coordination algorithm to find an optimal nodes cooperation of the network to maximize the energy conservation while preserving the tracking performance. Experimental results show that EENC can achieve energy saving of at least 38.2% compared to state-of-the-art approaches.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.393-399
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• 2009

This paper introduces an automated tool named Advanced Stochastic Schedule Simulation System (AS4). The system automatically integrates CPM schedule data exported from Primavera Project Planner (P3) and historical activity duration data obtained from a project data warehouse, computes the best fit probability distribution functions (PDFs) of historical activity durations, assigns the PDFs identified to respective activities, computes the optimum number of simulation runs, simulates the schedule network for the optimum number of simulation runs, and estimates the best fit PDF of project completion times (PCTs). AS4 improves the reliability of simulation-based scheduling by effectively dealing with the uncertainties of the activities' durations, increases the usability of the schedule data obtained from commercial CPM software, and effectively handles the variability of the PCTs by finding the best fit PDF of PCTs. It is designed as an easy-to-use computer tool programmed in MATLAB. AS4 encourages the use of simulation-based scheduling because it is simple to use, it simplifies the tedious and burdensome process involved in finding the PDFs of the many activities' durations and in assigning the PDFs to the many activities of a new network under modeling, and it does away with the normality assumptions used by most simulation-based scheduling systems in modeling PCTs.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.459-466
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• 2013

Risk exists in all construction projects and resides among the collection of subcontractors and their array of individual activities. Wherever risk resides, the interrelation of participants to one another becomes paramount for the way in which risk is measured. Inherent risk becomes recognizable and quantifiable within network schedules in the form of consuming float - the flexibility to absorb delays. Allocating, owning, valuing, and expending such float in network schedules has been debated since the inception of the critical path method itself. This research investigates the foundational element of a three-part approach that examines how float can be traded as a commodity, a concept whose promise remains unfulfilled for lack of a holistic approach. The Capital Asset Pricing Model (CAPM) of financial portfolio theory, which describes the relationship between risk and expected return of individual stocks, is explored as an analogy to quantify the inherent risk of the participants in construction projects. The inherent relationship between them and their impact on overall schedule performance, defined as schedule risk -the likelihood of failing to meet schedule plans and the effect of such failure, is matched with the use of CAPM's beta component - the risk correlation measure of an individual stock to that of the entire market - to determine parallels with respect to the inner workings and risks represented by each entity or activity within a schedule. This correlation is the initial theoretical extension that is required to identify where risk resides within construction projects, allocate and commoditize it, and achieve actual tradability.

• 대한토목학회논문집
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• 제28권3D호
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• pp.347-353
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• 2008

일반적으로 건설공사의 품질을 확보하고 불필요한 공기지연을 사전에 예방하기 위해서는 각 공정의 내용을 정확하게 숙지하고 관리하는 일이 중요하다. 더욱 중요한 것은 공사계획에 따른 공정이 원활하게 진행될 수 있도록 각각의 공정에 필요한 사전작업들을 체계화하여 관리하는 것이다. 본 연구에서는 건설공사의 품질확보와 공기지연의 사전예방 등의 효과적인 공사진행을 위해서 아파트공사중 토목공사의 공종별로 필요한 사전작업을 일정별로 구분하여 확인, 검사, 승인 등을 체계적으로 할 수 있도록 하였다. 또한 건설공사 실무자들의 체험적인 방법을 통하여 공정표의 작업일정을 토대로 작업담당자별로 사전작업관리항목을 설정하여 제시하였다.