• 인터넷정보학회논문지
• /
• 제8권4호
• /
• pp.105-117
• /
• 2007

프로젝트 관리자는 입찰 또는 개발을 성공하기 위해 비용과 일정을 프로젝트 초기 단계에서 보다 정확히 추정해야만 한다. 평균적으로 대부분의 프로젝트들이 수행하고 있는 명목상의 개발기간은 경험법칙, 선형함수 추정경험 또는 개략적 일정 추정표로부터 유도할 수 있다. 명목상 개발기간에는 다양한 경험법칙이 존재하며, 선형함수 모델은 충분한 정보를 제공하지 못하여 특정 규모의 프로젝트에 적합한 개발노력과 일정을 결정하기 어렵다. 본 논문은 개략적 일정 추정표로부터 개발노력과 일정을 유도하는 통계적 회귀분석 모델을 제시하였다. 먼저, 개략적 일정 추정표에서 제시하고 있는 최대 단축기간, 효율적 개발기간과 명목상 개발기간을 재정의 하였다. 다음으로 개발노력과 기간과의 관계를 고찰하고, 개략적 일정추정표에 제시되지 않은 특정 규모의 소프트웨어에 대한 개발노력 추정 모델과 개발노력에 따른 일정을 보다 정확히 추정할 수 있는 모델을 제시하였다. 제시된 회귀분석 모델은 기존의 방법들과 비교하여 상대오차를 최대 2%까지 줄이는 효과를 얻었다. 또한, 특정 규모의 소프트웨어에 대해서도 개발노력과 일정을 추정할 수 있었다.

• 한국정보처리학회논문지
• /
• 제7권7호
• /
• pp.2050-2059
• /
• 2000

In a video-on-Demand(VOD) service, a server has to return to he normal playback quickly at a certain new frame position after interactive operations such as jump or last playback. In this paper, we propose an efficient scheme to write a transmission schedule for a playback restart of a video stream at a new frame position after interactive operations. The proposed scheme is based on convergence characteristics, that is transmission schedules with different playback startup frame position in a video stream meet each other at some frame position. The scheme applies a bandwidth smoothing from a new frame position to a convergence position without considering all remaining frames of a video stream. And then the scheme transmits video dta according to the new schedule from the new frame position to the convergence position, and then transmits the remaining video data according to the reference schedule from the convergence position, and then transmits the remaining video data according to the reference schedule from the convergence position to the last frame position. In this paper, we showed that there existed the convergence position corresponding to nay frame position in a video stream through many experiments based on MPEG-1 bit trace data. With the convergence we reduced the computational overhead of a bandwidth smoothing, which was applied to find a new transmission schedule after interactive operations. Also, storage overhead is greatly reduced by storing pre-calculated schedule information up to the convergence position for each I frame position of a video stream with video data off-line. By saving information on a transmission schedule off-line along with the video data and searching the schedule corresponding to the specified restarting frame position, we expect the possibility of normal playback of a video stream with small tolerable playback startup delay.

• 대한건축학회논문집:구조계
• /
• 제34권3호
• /
• pp.61-68
• /
• 2018

As construction projects become larger, higher and more complex, efficient use of information is increasingly more important. As a result, there is a growing demand to apply BIM data obtained in the design stage to the construction stage. In this study, we propose a BIM-based construction schedule management system in order to promote introduction and application of BIM in the construction stage. Specifically, we provided how to build BIM database to be used for construction schedule management, and proposed how to obtain progress information and enter information based on analysis of progress schedule. We also provided a system of classifying construction works for more systematic use of BIM database, a process of using BIM database in construction projects, and a step-by-step guideline on how to establish the system. The proposed construction schedule management system provides information on particular construction schedule, as well as information and progress chart on delayed parts of the work so that a change in schedule can be managed. Additionally, by linking system database with the BIM model, construction progress can be checked in 3D simulation and a delay in construction schedule can be managed. As a result, using BIM at construction sites contributes to improving project productivity.

• 한국경영과학회:학술대회논문집
• /
• 한국경영과학회 2000년도 추계학술대회 및 정기총회
• /
• pp.268-271
• /
• 2000

In these days, the technical advances and complexities have generated much of the difficulties in managing the project resources, both time and costing to accomplish the project in the most efficient manner. The project manager is frequently required to render judgements concerning the schedule and resource adjustments. This research develops an analytical model for a schedule-cost and risk analysis based on visual PERT/CPM. We used a two-step approaches ：in the step 1, a deterministic PERT/CPM model for the critical path and estimating the project time schedule and related resource planning, In the second step, we developed a heuristic model for crash and stretch out analysis based upon a time-cost trade-off associated with the crash and stretch out of the project. Computer implementation of this model is provided based on GUI-Type objective-oriented programming for the users and provided displays of all the inputs and outputs in the form of visual graphical. Also developed GUI-type program, Dongeui Visual-PERT/CPM. The results of this research will provide the project managers with an efficient management tool.

• 경영과학
• /
• 제21권1호
• /
• pp.39-55
• /
• 2004

Efficient crew scheduling for cockpit crew is important in airline industry due to operational safety and cost associated with the flight duty time. Because of complexity of regulations imposed to the cockpit crew. it is complicated to generate an efficient schedule. Schedule of cockpit crew can be generated through two steps; selecting of flight patterns. and scheduling of them to the specific time horizon. Heuristic method is developed and applied with massive data in a limited time of computation. A set of flight patterns is selected from all possible flight patterns. which are generated by composing the flight leg based on regulations. by using the set partitioning problem with objective function of oversea stay cost. The selected set of flight patterns found at the first step is allocated to 4 week crew schedule to minimize the variance of total fight time assigned to each crew. The crew schedules obtained are evaluated and compared with the ones currently used in one of major airline company.

• 한국경영과학회지
• /
• 제21권3호
• /
• pp.75-88
• /
• 1996

This paper presents an efficient heuristic technique for minimizing the objectives related to tardiness such as total tardiness, maximum tardiness and root mean of tardiness in the job shop scheduling. The heuristic technique iteratively improves an active schedule through exploring the schedule's neighborrhood, using operation move methods. The move operatio is defined on an active chain of tardy jobs in the active schedule. To find the move operations which have a high probability of reducing tardiness, we develop move methods by exploiting the properties of active chains. Our technique is compared with the two existing heuristic techniques, that is, MEHA(Modified Exchange Heuristic Algorithm) and GSP(Global Scheduling Procedure) under the various environmental with the three levels of due date tightness and several sized problems. The experimental results show that the proposed technique outperforms the two exissting techiques in terms of solution quality and computation time.

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

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제13권3호
• /
• pp.1674-1688
• /
• 2019

As environmental pollution and fossil fuel energy problems from fuel vehicle have occurred, the interest of electric vehicle(EV) has increased. EV industry and energy industry have grown dynamically in these days. It is expected that the next generation of primary transportation will be EV, and it is necessary to prepare EV infra and efficient energy management such as EV communication protocol, EV charge station, and smart grid. Those EV and energy industry fields are now on growth. Also, the study and development of them are now in progress. In this paper, distributed charge signal processing software for smart slow and quick EV charge is proposed and designed for dealing with EV charge demand. The software consists of smart slow and quick EV charge schedule engine and EV charge power distribution core. The software is designed to support two charge station types. One is normal EV charge station and the other is bus garage EV charge station. Both two types collect the data from EV charge stations, and then analyze the collected data. The software suggests optimized EV charge schedule and deliveries EV charge power distribution information to power switchboard system, and the designed software is implemented on embedded system. It is expected that the software provides efficient EV charge schedule.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
• /
• pp.1028-1031
• /
• 1996

Dynamic scheduling is very important in constructing CIM and improving productivity of chemical processing systems. Computation at the scheduling level requires mostly a long time to generate an optimal schedule, so it is difficult to immediately respond to actual process events in real-time. To solve these problems, we developed dynamic scheduling algorithms such as DSMM(Dynamic Shift Modification Method), PUOM(Parallel Unit Operation Method) and UVVM(Unit Validity Verification Method). Their main functions are to minimize the effects of unexpected disturbances such as process time variations and unit failure, to predict a makespan of the updated dynamic schedule and to modify schedule desirably in real-time responding to process time variations. As a result, the algorithms generate a new pertinent schedule in real-time which is close to the original schedule but provides an efficient way of responding to the variation of process environment. Examples in a shampoo production batch process illustrate the efficiency of the algorithms.

• 한국건설관리학회:학술대회논문집
• /
• 한국건설관리학회 2006년도 정기학술발표대회 논문집
• /
• pp.105-110
• /
• 2006

건설공사에서 발생하는 리스크는 시공단계에 많이 발생하므로 공정관리와 통합하여 관리할 수 있다면 효율적일 것이다. 본 연구에서는 공정관리 프로그램을 이용하여 공정리스크를 통합관리하는 방법을 제안하고 있다. 제안된 방법은 사용자 프로그래밍(Visual Basic Application)이 가능한 Microsoft Project에서 구현되었으며, 공사관리자가 공정표를 작성하고 일정관리를 수행하는 과정에서 리스크를 예측하는데 도움을 줄 수 있을 것이다.