• International conference on construction engineering and project management
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• 2005.10a
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• pp.980-985
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• 2005

Since the 1980s, Build-Operate-Transfer and its variations have become a common approach to develop large-scale infrastructure projects. Despite the slight variations in contractual settings, the key issue for all parties concerned is to assess the risks and uncertainties inherent in a project. The risk factors studied and highlighted by past researchers are very diverse. This paper starts with an objective to compare the risk factors in different sectors of infrastructure, and then categorize them into two kinds: general and specific. Following this classification, risk mitigation strategies should be adopted differently at the corporate and project levels. A few short cases have also been used to illustrate the flexible measures or "options" that some project participants have designed to address risks and uncertainties at the two levels.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.330-334
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• 2011

Build-operate-transfer (BOT) projects are privatized infrastructure undertakings that face long-term investment risks and uncertainties. To ensure these projects can be completed on time and operated according to performance specifications, governments usually require BOT concessionaires to furnish performance bonds as a security. However, in order to attract investment, governments often provide abandonment rights for concessionaires to deal with investment risks and uncertainties. In the context of real options, these abandonment rights will increase project value, but the furnish of performance bonds will reduce this value. Currently in the BOT context, there is no real option model that can handle explicitly the impact of performance bonds on project value. In this paper, a real option valuation model is derived to deal with this important issue. The Taiwan high-speed rail project is used as a case study to show the applicability of the proposed model.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.4
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• pp.72-80
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• 2016

The market size of plant projects in overseas is so large that domestic EPC project contractors are actively seeking the overseas projects and then trying to meet completion plans since successful fulfillment of these projects can provide great opportunities for them to expand into new foreign markets. International EPC projects involve all of the uncertainties common to domestic projects as well as uncertainties specific to foreign projects including marine transportation, customs, regulations, nationality, culture and so on. When overseas project gets off-schedule, the resulting uncertainty may trigger unexpected exceptions and then critical effects to the project performance. It usually require much more time and costs to encounter these exceptions in foreign sites compared to domestic project sites. Therefore, an exception handling approach is required to manage exceptions effectively for successful project progress in foreign project sites. In this research, we proposed a methodology for prediction and evaluation of exceptions caused by risks in international EPC projects based on sensitivity analysis and Bayesian Networks. First, we identified project schedule risks and related exceptions, which may meet during the fulfillment of foreign EPC projects that is performed in a sequence of engineering, procurement, preparatory manufacture, foreign shipping, construction, inspection and modification activities, and affect project performance, using literature review and expert interviews. The impact of exceptions to the schedule delay were also identified. Second, we proposed a methodology to predict the occurrence of exceptions caused by project risks and evaluate them. Using sensitivity analysis, we can identify activities that critically affect schedule delay and need to focus by priority. Then, we use Bayesian Networks to predict and evaluate exceptions. Third, we applied the proposed methodology to an international EPC project example to validate the proposed approach. Finally, we concluded the research with the further research topics. We expect that the proposed approach can be extended to apply in exception management in project management.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.902-907
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• 2005

This study was undertaken to develop a comprehensive scheduling method which applied the core concept(DBR) of TOC to PERT, and to combine Monte Carlo Simulation to revise the uncertainties of activities then to eliminate project duration uncertainty. Most of the project duration overlooks the fact that in spite of minimizing the project duration, the uncertainty of constrained resources still puts the reliability of project duration in jeopardy. For the contractor, however, the most important thing is to comply the project scheduling with the planning to reduce the uncertainty of the project activities, operational interaction and project duration. In order to demonstrate that the model can be used in construction project, the scheduling of a steel-structure project was used as a case study to verify the validity of this model.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.49.1-49.1
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• 2011

Utilizing single-epoch spectra and the empirical relation between the size of the broad-line region and AGN continuum luminosity, the so-called single-epoch method has been widely used for estimating AGN black hole masses. However, the systematic uncertainties and the potential biases of this method are not well examined. Taking the full advantage of the high-quality homogeneous spectra from the Lick AGN Monitoring Project (LAMP), we investigate in detail the uncertainties of single-epoch mass estimates by comparing with the reverberation-mapping results. We find that the uncertainty due to AGN variability is less than 0.1 dex, while there is a systematic offset between single-epoch masses and reverberation masses. Particularly, narrow-line Seyfert 1 galaxies show that the Hbeta line widths measured from single-epoch (or mean) spectra are systematically larger than those from rms spectra, indicating a potential bias of single-epoch masses. We will present the detailed measurement method, the test of virial assumption, and the systematic uncertainties.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2007.04a
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• pp.129-146
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• 2007

[ ${\square}$ ] A mathematical model has been developed and used to analyze the limits of He fine leak test. ${\square}$ Uncertainties inherent in using the MIL-STD-883 guidelines for hermeticity evaluation of small packages have been demonstrated. ${\square}$ A new methodology to quantitatively characterize hermeticity has been developed.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.929-934
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• 2005

The complex and dynamic job nature and the ever-changing working environment of construction projects inevitably present uncertainties to construction operations. Identification, evaluation and control of uncertainties constitute main elements of risk management and critical tasks of project management in construction. This paper is focused on application of a simplified discrete-event simulation approach in management of schedule-overrun risks, each being the combination of the occurrence probability of an uncertain interruptive factor and its potential consequence in terms of time delay. A case study observed from a concreting operation in Hong Kong is converted into a simulation model and analyzed with an in-house-developed simulation package for demonstrating how the proposed approach can be implemented to manage multiple schedule-overrun risks on construction projects.

• Journal of Information Technology Services
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• v.8 no.4
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• pp.41-55
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• 2009

Due to the global business environments and severe competitions, SMEs have carried out IS projects for their competitive advantages. However, numerous organizations have faced with difficulties in the IS project management such as large amounts of IT expenses and uncertainties in project implementations. Thus, this study is intended to discover critical risk factors in the IS project management. To achieve this research goal, we have mailed questionnaires to SMEs and SI companies that experienced IS project failures and 63 usual data were collected. The result of analysis with step wise regression showed that 6 factors are related with IS project failures. The study contributes to the literature in two ways. First, this paper empirically identifies IS risk factors for SME manufactures. Second, this research result can be utilized as a checklist for the successful IS implementations. Limitations and future research topics are also discussed.

• Korean Journal of Construction Engineering and Management
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• v.15 no.6
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• pp.44-52
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• 2014

Generally, the most difficult works at scheduling are to estimate the duration of activities and linkages between them because the possibility that the duration and linkages could be exposed to the uncertainties is so high. When estimating a project duration, therefore, the probabilistic estimation of the duration as well as the probabilistic estimation of the linkages between activities should be considered concurrently. The PERT that is one of the most popular techniques applied for the probabilistic estimation of a project duration can not consider the uncertainties of the linkages because it only estimates the probabilistic duration limited to 'FS0' relationship. The purpose of this study is to propose the new method "PLET" for stochastically estimating the project duration based on the probabilistic estimation of the BDM's relationships, and also provide more wide and various probabilsitic information about the project duration by it.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.169-173
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• 2015

The linear scheduling method or line-of-balance (LOB) is a popular choice for projects that involve repetitive tasks during project execution. The method, however, produces deterministic schedule that does not convey a range of potential project outcomes under uncertainty. This results from the fact the basic scheduling parameters such as crew production rates are estimated to be deterministic based on single-point value inputs. The current linear scheduling technique, therefore, lacks the capability of reflecting the fluctuating nature of the project operation. In this paper the authors address the issue of how the variability of operation and production rates affects schedule outcomes and show a more realistic description of what might be a realistic picture of typical projects. The authors provide a solution by providing a more effective and comprehensive way of incorporating the crew performance variability using a Monte Carlo simulation technique. The simulation outcomes are discussed in terms of how this stochastic approach can overcome the shortcomings of the conventional linear scheduling technique and provide optimum schedule solutions.