• 한국경영과학회지
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• 제35권4호
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• pp.33-53
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• 2010

When purchase prices of a raw material fluctuate over time, the total purchasing cost is mainly affected by reordering time. Existing researches focus on deciding the right time when the demand for each period is replenished at the lowest cost. However, the decision is based on expected future prices which usually turn out to include some error. This discrepancy between expected prices and actual prices deteriorates the performance of inventory models dealing with fluctuating purchase prices. In this paper, we propose a new inventory model which incorporates not only cost but also risk into making up a replenishment schedule to meet each period's demand. For each replenishment schedule, the risk is defined to be the variance of its total cost. By introducing the risk into the objective function, the variability of the total cost can be mitigated, and eventually more stable replenishment schedule will be obtained. According to experimental results from crude oil inventory management, the proposed model showed better performance over other models in respect of variability and cost.

• 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.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.897-901
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• 2005

In the highway engineering, the performance, quantity and status of machines available for the project have direct impact on the project time. For instance, the status of machines, such as working or in trouble, have great influence on the activity execution. Therefore, while scheduling the project, the project manager always increases the spare machines or prolong the activity time to avoid delaying the project time when some of the machines are in trouble in construction site. However, how many are the spare machines and how long are the prolonged activity time, which are estimated subjectively by the manager. This subjective estimation has been criticized for systematically overestimating or underestimating quantity of the machines and the activity time. In the paper, we propose and prototype a model to simulate the status of the machines in construction site, and then to evaluate the schedule feasibility considering the performance, quantity and statues of the machines involved.

• 한국건설관리학회논문집
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• 제10권1호
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• pp.69-77
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• 2009

최근 도심재생사업에 대한 관심과 연구가 활발히 진행되고 있다. 이는 기존 도시의 노후화된 건물과 저급화된 기반시설로 인해 파생되는 사회적 경제적 문제들을 새로운 도시개발 즉 재개발사업을 통해 해결하려는 노력의 일환이다. 그러나 도심재생사업은 사업에 관계되는 다양하고 복잡한 이해관계자들과 규모의 방대함으로 수많은 위험에 노출되어 있어 사업의 성과를 보장할 수 없다는 특징을 가지고 있다. 본 연구는 도심재생사업과 같은 메가 프로젝트의 성과관리를 함에 있어, 기존의 비용/공정 중심의 성과측정체계를 위험관리 관점으로 확장시킴으로서 메가 프로젝트에 대한 종합 성과관리의 효율성을 향상시키기 위한 목적으로 위험성과지수 방법론을 제시하였다. 본 연구에서 제시한 위험성과지수 방법론은 기존의 EVMS와 유사한 체계를 갖추고 있고, 위험성과지수를 구성하는 18종류의 세부지수와 변수를 통해 비용/공정/위험의 3차원적 통합 성과관리가 가능하게 하였다.

• 대한전기학회논문지:전력기술부문A
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• 제55권6호
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• pp.242-248
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• 2006

This paper proposes a coordinated control method for under-load tap changers (ULTCs) with shunt capacitors to reduce the operation numbers of both devices. The proposed method consists of two stages. In the first stage, the dispatch schedule is determined using a genetic algorithm with forecasted loads to reduce the power loss and to improve the voltage profile during a day. In the second stage, each capacitor operates according to this dispatch schedule and the ULTCs are controlled in real time with the modified reference voltages considering the dispatch schedule of the capacitors. The performance of the method is evaluated for the modified IEEE 14-bus system. Simulation results show that the proposed method performs better than a conventional control method.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.143-144
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• 2012

A number of construction projects tied to the concerns and decision-making is also very complicated. In addition, more than any other industry, is inherent in many risk factors. In the course of the construction project on risk factors that exist in the early stages of project risk factors to predict in advance and prepare a project by shortening the construction period and project cost as you can to maximize performance. In this study, I proposed risk management processes and how they are used in web-based schedule risk in the process of change management system, and between 3D CAD, 4D CAD taking into account the linkages, risk management strategy process in the BIM environment.

• ETRI Journal
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• 제46권3호
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• pp.473-484
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• 2024

We introduce a machine learning-based web application to help travel agents plan a package tour schedule. K-nearest neighbor (KNN) classification predicts the optimal tourists' dwelling time based on a variety of information to automatically generate a convenient tour schedule. A database collected in collaboration with an established travel agency is fed into the KNN algorithm implemented in the Python language, and the predicted dwelling times are sent to the web application via a RESTful application programming interface provided by the Flask framework. The web application displays a page in which the agents can configure the initial data and predict the optimal dwelling time and automatically update the tour schedule. After conducting a performance evaluation by simulating a scenario on a computer running the Windows operating system, the average response time was 1.762 s, and the prediction consistency was 100% over 100 iterations.

• 기본간호학회지
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• 제1권1호
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• pp.77-97
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• 1994

The circadian system represents a temporal order which is mediated by the mutual coupling of oscillators and by the synchronizing effects of zeitgebers. It is known that well-being of man depends partly on the maintenance of this order, and that repeated or long lasting disturbances to it such as shift work will Cause harmful effects. This study was a quasi-experimental study to test the effect of shift directions for the clinical nurses on the circadian rhythm. Fourteen nurses working at the general units of Y hospital were selected according to the established criteria. Fourteen subjects were assigned to a weekly shift but the directions of shift work were phase delay first and then phase advance or vice versa. Oral temperature, total sleeping time, frequency of sleep-wake cycle, fatigue, mental performance, and physical symptom were measured during these days except holidays. The data collection period was from April 26, 1993 to July 3, 1993. MANOVA and Wilcoxon signed rank test were used for statistical analysis. The results are summarized as follows. 1. Having worked on evening and night shifts in either phase delay or phase advance schedules, temperature rhythms of shift workers were gradually adapted to the new sleep-wake cycles. A complete adaptation to work on the night shift was achieved the sixth day of the night shift in the phase delay schedule compared to the partial adaptation to the work on the night shift in the phase advance schedule. Accordingly, by putting evening shift between day and night shifts, it will be possible for circadian rhythm to adapt easily to the night shift. 2. There were differences in the total sleeping time, frequency of steep-wake cycle, fatigue, and physical symptom except for mental performance between night shift and day, evening shift. This indicates further that shift workers working on the night shift have a hard time adapting to the shift work compared to the other shifts. 3. Evaluating all the acrophases of temperature rhythm either in phase delay or phase ad-vance schedules, it was shown that night to evening shift in the phase ad-vance schedule revealed the smallest phase move. Also phase advance schedule showed poorer adaptation to shift work than phase delay schedule in connection with total sleeping time, frequency of sleep-wake cycle, fatigue, mental performance, and physical symptom. It is suggested, taken together, these findings reflect that phase delay schedule facilitated the degree of adjustment to the shift work compared to the phase advance schedule.

• 한국IT서비스학회지
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• 제10권4호
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• pp.191-204
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• 2011

Recently, many software companies are trying to improve the software quality and project outcome with more costs and efforts in development time. In the software convergence and integration environments, it is required efforts to gain high quality of software. In other words, it is required to utilize software engineering knowledge and technology for higher software quality and better software project productivity. The Software development productivity can be varied by software process capability according to building a framework for software development, selection and use of appropriate technology, human resource management. Software process capability will influence software project outcome which is the general opinion. This study provides empirical evidence about software engineering efforts and investment approach to lead software project performance. We measured the software engineering efforts by SW engineering level and analyzed the corelation between software engineering level and schedule deviation. And, we verified that this performance is affected by the size of software company. As a result, software process capability is important to build a infrastructure and develop systematically software project. The higher software engineering level can lead to improved software project performance.

• 한국국방경영분석학회지
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• 제32권1호
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• pp.73-89
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• 2006

이 논문에는 한국형 헬기 시제품(KHP) 개발을 위한 EVMS 적용절차를 제시하였다. 무기체계의 연구개발은 사업기간이 긴 사업으로서 불확실성과 위험에 기인한 비용상승의 확률이 높다. 따라서 일정과 기술적 성능을 만족하고 초과비용을 억제하는 것이 연구개발사업을 성공하기 위한 주요 관건이다. EVMS는 성과를 활용하여 비용, 일정 및 기술적 성능을 통제하는 사업관리시스템이다. 그러므로 한국형 헬기 시제품 개발사업의 비용 및 일정을 통해하고, 기술적 성능을 만족시키기 위하여 EVMS의 적용이 요구된다.