• 한국건설관리학회논문집
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• 제5권6호
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• pp.72-79
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• 2004

기존의 CPM 관리방식은 정해진 시간과 비용 내에서 프로젝트를 완료하기 위한 목적으로 건설분야에 활용되어 공기지연이 발생하지 않도록 관리하는데 초점을 두고 있으나, 조기 완공을 유도하지는 못하여 왔다. 기존의 CPM 공정계획의 경우에 학생증후군(Student Syndrome)과 파킨슨법칙(Parkinson's Law)이 작용할 경우 조기 완공의 효과를 얻기는 어렵다. 본 연구는 건설 프로젝트의 공기 산정에 제약이론(Theory of Constraints)을 적용하였으며, 이는 공정계획에서의 새로운 관리기법을 개발하는데 사용되어온 Critical Chain을 일컫는다. 이러한 Critical Chain의 개념은 기존 공정계획 방법에서의 문제점을 해결하기 위하여 이용되었다 본 논문에서는 기존 공정계획 방법의 문제점을 해결하기 위하여 Critical Chain의 개념을 적용하여 확률적인 공기산정과 공정버퍼(buffer)를 이용한 공정계획 합리화 방안을 제시하였다.

• Biomolecules & Therapeutics
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• 제27권5호
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• pp.435-441
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• 2019

The capsaicin receptor TRPV1 (transient receptor potential vanilloid 1) has been an object of intense interest for pharmacological development on account of its critical role in nociception. In the course of structure activity analysis, it has become apparent that TRPV1 ligands may vary dramatically in the rates at which they interact with TRPV1, presumably reflecting differences in their abilities to penetrate into the cell. Using a fast penetrating agonist together with an excess of a slower penetrating antagonist, we find that we can induce an agonist response of limited duration and, moreover, the duration of the agonist response remains largely independent of the absolute dose of agonist, as long as the ratio of antagonist to agonist is held constant. This general approach for limiting agonist duration under conditions in which absolute agonist dose is variable should have more general applicability.

• 한국중재학회지:중재연구
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• 제32권4호
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• pp.103-141
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• 2022

Traditionally, schedule analysis in Korea has been used, mainly through the Critical Path Method, to evaluate the claim for extension of time and/or the amount of liquidated damages for delay. Critical path method, however, cannot identify the delay event and its impact occurred in non-critical path especially in multi facility projects. In multi facility projects that comprise several independent but related facilities or structures, each facility has its own facility critical path the duration of which will be impacted by facility specific critical delays. Thus, only through the non-critical delay analysis along with the critical delay analysis damages not attributable to contractors may be remedied in full. Because all the records and pictures can reveal what has actually happened in post contract review, only the retrospective analysis rather than the prospective analysis based on the assumptions can establish the cause and allocate the each parties' responsibilities appropriately.

• 한국해양공학회지
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• 제37권4호
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• pp.164-171
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• 2023

Vibration and noise must be considered to maximize the efficiency of a yaw system and reduce the fatigue load acting on a wind turbine. This study investigated a method for analyzing yaw-system vibration based on the change in the load-duration distribution (LDD). A substructure synthesis method was combined with a planetary gear train rotational vibration model and finite element models of the housing and carriers. For the vibration excitation sources, the mass imbalance, gear mesh frequency, and bearing defect frequency were considered, and a critical speed analysis was performed. The analysis results showed that the critical speed did not occur within the operating speed range, but a defect occurred in the bearing of the first-stage planetary gear system. It was found that the bearing stiffness and first natural frequency increased with the LDD load. In addition, no vibration occurred in the operating speed range under any of the LDD loads. Because the rolling bearing stiffness changed with the LDD, it was necessary to consider the LDD when analyzing the wind turbine vibration.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2009년도 정기 학술발표대회
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• pp.145.1-145.1
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• 2009

• 한국농공학회지
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• 제41권1호
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• pp.39-51
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• 1999

This study has an object to evaluate runoff characteristics with ILLUDAS model and SWMM owing to each rainfall distribution type of Huff's quartile and each rainfall duration time of 30 ,60, 120 and 180 minutes. As a result of this study, Type-Ⅰ Extreme (TIE) rainfall distribution pattern with Huff's 2nd quartile is adequate for Cheju volcanic island . To decide optimal rain fall duration , time of concentration and critical duration should be compared and analyzed each other. In this study, 30 and 120 miniutes were suggeste to iptiaml duration time of A and B study basins. It is concluded that the magnitude of peak runoff discharge is maximum with Huff's 4th quartile, and that of total runoff volume is maximum with Huff's 4th quartile for ILLUDAS model and with Huff's 1st quartile for SWMM. As rainfall duration time increasing is increasing . Also in case of total runoff volume, volumen by SWMM is less than by ILLUDAS model as to variation ratio of total runoff volume in A and B study basin. Therefore, the resulots of this study canb e sued as basic data in determining adequate rainfoal duration time and rainfall distribution type and used for urban drainage systems analysis and design at small urbanization catchment is Cheju volcanic island.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.397-402
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• 2013

In super-tall building construction projects, schedule risk factors which vertically change and are not found in the low and middle-rise building construction influence duration of a project by vertical attribute; and it makes hard to estimate activity or overall duration of a construction project. However, the existing duration estimating methods, that are based on quantity and productivity assuming activities of the same work item have the same risk and duration regardless of operation space, are not able to consider the schedule risk factors which change by the altitude of operation space. Therefore, in order to advance accuracy of duration estimation of super-tall building projects, the degree of changes of these risk factors according to altitude should be analyzed and incorporated into a duration estimating method. This research proposes a simulation model using Monte Carlo method for estimating activity duration incorporating schedule risk factors by weather conditions in a super-tall building. The research process is as follows. Firstly, the schedule risk factors in super-tall building are identified through literature and expert reviews, and occurrence of non-working days at high altitude by weather condition is identified as one of the critical schedule risk factors. Secondly, a calculating method of the vertical distributions of the weather factors such as temperature and wind speed is analyzed through literature reviews. Then, a probability distribution of the weather factors is developed using the weather database of the past decade. Thirdly, a simulation model and algorithms for estimating non-working days and duration of each activity is developed using Monte-Carlo method. Finally, sensitivity analysis and a case study are carried out for the validation of the proposed model.

• 대한건축학회논문집:구조계
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• 제35권4호
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• pp.175-184
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• 2019

To improve productivity in the architecture, construction and engineering industry, it is critical to understand both current and historic trends in construction productivity. This study analyzes and compares construction productivity trends of South Korea, the U.S., the U.K., and Japan 1995 to 2015 using the following three measures: construction labor productivity, construction duration per floor, and construction duration per 1,000 m2 floor area. As the results, the international competitiveness of each country varied according to which measures were used to analyze them. Among the four countries, the construction labor productivity of the U.S. was the highest, followed by that of South Korea. South Korea also had the second highest productivity growth rate, following that of Japan. On the other hand, when analyzed from the perspective of construction duration, the construction productivity in South Korea appeared relatively lower than those of other countries. There were differences in the location of construction competitiveness of each country analyzed by various measures. Therefore, to accurately diagnose and improve the construction competitiveness in South Korea, strategies based on various measures are need to established simultaneously.

• 한국컴퓨터정보학회논문지
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• 제20권9호
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• pp.81-86
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• 2015

This paper suggests heuristic algorithm with linear time complexity to decide the normal and optimal point at minimum loss/maximum profit maximum shortest scheduling problem with additional loss cost and bonus profit cost. This algorithm computes only the earliest ending time for each node. Therefore, this algorithm can be get the critical path and project duration within O(n) time complexity and reduces the five steps of critical path method to one step. The proposed algorithm can be show the result more visually than linear programming and critical path method. For real experimental data, the proposed algorithm obtains the same solution as linear programming more quickly.

• Journal of Advanced Research in Ocean Engineering
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• 제4권4호
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• pp.163-173
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• 2018

There are many issues in fluid structure interactions when dealing with the free surface flows in a sloshing tank. For example the problem of how yielding a highly nonlinear wave with a simple forced motion over a short duration is of concern here. Nonlinear waves are generated in a rectangular tank which is forced horizontally; its motion consists of a single cycle of oscillation. One of the objectives is to end up with a shape of the free surface yielding a wide range of critical flows by tuning few parameters. The configuration that is studied here concerns a plunging breaker accompanied with a critical jet where great kinematics are simulated. The numerical simulations are performed with a twodimensional code which solves the fully nonlinear free surface boundary conditions in Potential Theory.