• 국제학술발표논문집
• /
• The 1th International Conference on Construction Engineering and Project Management
• /
• pp.935-940
• /
• 2005

This paper presents the results of a statistical analysis using historical data of cost contingency. As a result, a model that predicts and estimates an accurate cost contingency value using the least squares estimation method was developed. Data such as original contract amounts, estimated contingency amounts set by maximum funding limits, and actual contingency amounts, were collected and used for model development. The more effective prediction model was selected from the two developed models based on its prediction capability. The model would help guide project managers making financial decisions when the determination of the cost contingency amounts for multiple projects is necessary.

• 전기학회논문지
• /
• 제57권7호
• /
• pp.1150-1156
• /
• 2008

This paper introduces the PC clustering of the SIMD structure for a distributed processing of on-line contingency to assess a static security of a power system. To execute on-line contingency analysis of a large-scale power system, we need to use high-speed execution device. Therefore, we constructed PC-cluster system using PC clustering method of the SIMD structure and applied to a power system, which relatively shows high quality on the high-speed execution and has a low price. SIMD(single instruction stream, multiple data stream) is a structure that processes are controlled by one signal. The PC cluster system is consisting of 8 PCs. Each PC employs the 2 GHz Pentium 4 CPU and is connected with the others through ethernet switch based fast ethernet. Also, we consider N-1 line contingency that have high potentiality of occurrence realistically. We propose the distributed process algorithm of the SIMD structure for reducing too much execution time on the on-line N-1 line contingency analysis in the large-scale power system. And we have verified a usefulness of the proposed algorithm and the constructed PC cluster system through IEEE 39 and 118 bus system.

• Journal of the Korean Data and Information Science Society
• /
• 제27권6호
• /
• pp.1621-1629
• /
• 2016

This paper studies Bayesian pooling for analysis of categorical data from small areas. Many surveys consist of categorical data collected on a contingency table in each area. Statistical inference for small areas requires considerable care because the subpopulation sample sizes are usually very small. Typically we use the hierarchical Bayesian model for pooling subpopulation data. However, the customary hierarchical Bayesian models may specify more exchangeability than warranted. We, therefore, investigate the effects of pooling in hierarchical Bayesian modeling for the contingency table from small areas. In specific, this paper focuses on the methods of direct or indirect pooling of categorical data collected on a contingency table in each area through Dirichlet priors. We compare the pooling effects of hierarchical Bayesian models by fitting the simulated data. The analysis is carried out using Markov chain Monte Carlo methods.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1995년도 하계학술대회 논문집 B
• /
• pp.620-622
• /
• 1995

This paper presents an analysis of the voltage stability when the contingency is occured in the power system. The evaluation of voltage stability is examined by the system identification based on T/L losses and percent indicator which represents how relatively far-off from the voltage collapse. When contingency happens, the bus voltages can be calculated using the EMTP and then, the time-interval in contingency is linearized between the known operating points in nose curves. For the sample study, the 5-bus and 7-bus systems are selected and, countermeasures for the contingency are established in view of the voltage stability.

• Journal of Electrical Engineering and Technology
• /
• 제4권4호
• /
• pp.438-442
• /
• 2009

Voltage instability is a phenomenon that could occur in power systems due to stressed conditions. The result would be an occurrence of voltage collapse leading to total blackout of the system. Therefore, voltage collapse prediction is an important part of power system planning and operation, and can help ensure that voltage collapse due to voltage instability is avoided. Line outages in power systems may also cause voltage collapse, thereby implying the contingency in the system. Contingency problems caused by line outages have been identified as one of the main causes of voltage instability in power systems. This paper presents a new technique for contingency ranking based on voltage stability conditions in power systems. A new line stability index was formulated and used to identify the critical line outages and sensitive lines in the system. Line outage contingency ranking was performed on several loading conditions in order to identify the effect of an increase in loading to critical line outages. Correlation studies on the results obtained from contingency ranking and voltage stability analysis were also conducted, and it was found that line outages in weak lines would cause voltage instability conditions in a system. Subsequently, using the results from the contingency ranking, weak areas in the system can be identified. The proposed contingency ranking technique was tested on the IEEE reliability test system.

• 한국건설관리학회:학술대회논문집
• /
• 한국건설관리학회 2003년도 학술대회지
• /
• pp.226-229
• /
• 2003

건설사업관리자는 사업을 진행하기 전에 사업의 실패 및 예측하지 못한 위험 발생 가능성에 대비한 공사예비비를 항상 고려해야 한다. 공사예비비를 충분히 이해하지 않고 판단을 내리게 되면 리스크로 인한 총공사비에서의 초과 비용이 누적되어 향후 사업진행에 지장을 줄 수도 있기 때문이다. 그러나 공사예비비를 사업초기부터 고려한다면, 그 사업의 실행 여부를 결정할 시점에서 여러 가지 리스크에 충분히 대비할 수 있다. 그럼에도 불구하고 국내 건설사업에서 실제로 공사예비비를 사업투자나 분석에 반영하고 있는 경우는 적으며, 공사예비비를 정당하게 평가할 수 있는 프로세스 역시 부재하다. 따라서 본 연구에서는 건설사업에서 리스크를 고려한 총공사비가 수립될 수 있도록 공사비 증감요인을 분류하고, 적정 공사예비비의 산정을 보장하기 위해 회귀분석을 통한 공사예비비 산정 프로세스를 제시한다.

• 방사성폐기물학회지
• /
• 제20권4호
• /
• pp.541-550
• /
• 2022

When decommissioning nuclear power plant (NPP), the first task performed is cost estimation. This is an important task in terms of securing adequate decommissioning funds and managing the schedule. Therefore, many countries and institutions are conducting continuous research and also developing and using many programs for cost estimation. However, the cost estimated for decommissioning an NPP typically differs from the actual cost incurred in its decommissioning. This is caused by insufficient experience in decommissioning NPPs or lack of decommissioning cost data. This uncertainty in cost estimation can be in general compensated for by applying a contingency. However, reflecting an appropriate standard for the contingency is also difficult. Therefore, in this study, data analysis was conducted based on the contingency guideline suggested by each institution and the actual cost of decommissioning the NPP. Subsequently, TLG Service, Inc.'s process, which recently suggested specific decommissioning costs, was matched with ISDC (International Structure for Decommissioning Costing)'s work breakdown structure (WBS). Based on the matching result, the guideline for applying the contingency for ISDC's WBS Level 1 were presented. This study will be helpful in cost estimation by applying appropriate contingency guidelines in countries or institutions that have no experience in decommissioning NPPs.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권12호
• /
• pp.761-771
• /
• 2020

This study discusses the role of Board Monitoring Effectiveness (BME) on managers' decisions regarding the business strategies that fit the external business environmental conditions by using a contingency analysis approach. Furthermore, this study will examine how fit strategies affect Sustainability Reporting (SR) of listed companies on the Indonesia Stock Exchange (IDX) from 2014 to 2017. This study uses Conditional Mixed Process (CMP) technique. This CMP method is claimed to be more efficient in analyzing the TSL models. This study found that in highly uncertain conditions, BME had a positive influence on the probability of managers to choose prospector and defender strategies rather than analyzers. These results indicate that BME shows positive impact on the contingency fit between business strategies and environmental uncertainty. In addition, the study documents that only prospectors have a positive impact on SR, however this study failed to document that defenders have positive impact on SR. Meanwhile the unexpected result is analyzers have a significantly positive effect on SR. This study is the first study to investigate the role of BME in contingency fit between business strategies and environmental uncertainties and how it produces effects up to the level of SR.

• 대한전기학회논문지:전력기술부문A
• /
• 제52권7호
• /
• pp.363-370
• /
• 2003

This paper presents the analysis of the load transfer capacity and study of conductor size for variable contingencies in distribution systems. The operation capacity of feeders was changed to improve operation efficiency in KEPCO, considerations for contingencies are still based on the previous capacity. In order to cope with the changes such as operation capacity, it is necessary to study whether the present "contingency support criteria" is reasonable or not, also to confirm the whether the present criteria should be improved or not. We analyze the load transfer capacity and conductor size on a distribution system for contingency levels such as the substation-level, bank-level, feeder-level, and zone-level.one-level.

• 대한전기학회논문지
• /
• 제33권6호
• /
• pp.232-240
• /
• 1984

이 논문은 전력계통에서의 상정사고 해석과 상정사고 대책에 관한 감도 행열에 관해 새로운 앨고리즘을 제시 하였다. 이 앨고리즘은 다른 일방적인 상정사고 해석 앨고리즘에 비해 선로사고나 모선사고시 실재상황에서 일어나는 모선전력 변화를 고려하여 개선된 AC 조류 계산법을 사용하여 정확한 조류변화를 얻었고 계산시간을 단축했다. 이 앨고리즘을 워어드헤일 5모선 계통과 IEEE의 24모선 계통에 적용하여 만족할만한 결과를 얻었다.