• International conference on construction engineering and project management
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• 2009.05a
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• pp.642-648
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• 2009

Determining the total duration for a construction project is an integral part of project management in the construction industry. This is to ensure the project and all its associated activities can be carried out and completed within the time frame stipulated. There are several commonly used scheduling methods and techniques in project management, some of which involves manual calculation while others involve computer software. This paper looks into the various time determination methods, extracting out their differences and similarities. It also seeks to draw out the problems when determining time for projects, especially those encountered of case studies. Based on the results from the case studies, there were delays on certain projects even though time determination had been carried out rigorously prior to the commencement of the projects. This paper seeks to develop a time determination model, which incorporates risk management techniques into the calculations in order to improve the method for time estimation to minimize the chances of project delay.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.456-463
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• 2002

Nowadays. risk management in the enterprise is considered as the important activity. Risk management ran be defined as the activity which is the analysis of risk factors related to damages, the estimation of the magnitude of risk, and the determination of investment to protect damage in a company. Initially, risk management was originated in financial areas. But the concept of risk has been expanded in the enterprise. Most companies have extended their activities in various areas. In this tendency, most activities must be considered in supply chain So, risk management must be ronsidered as the concept in the viewpoint of supply chain. The framework of risk management in supply chain and the related mathematical model are represented in this paper. Risk management in supply chain ran provide a positive opportunity not only to protect various damages, but also to improve the relationship between partners.

• International Commerce and Information Review
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• v.9 no.4
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• pp.107-125
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• 2007

With the rapidly increasing of Korean enterprises, the importance of foreign exchange(FX) risk management for the future operation generated from FDI contract is becoming the critical problem of international business. This type of FX risk, called as "economic exposure risk", requires us of the unique risk management principles and techniques. In this paper, we identify the properties of economic exchange rate exposure, analyze the identification and measurement processes of risk sources and strength, and perform the estimation of the main determinants and its profile effects of the invoicing currency for the efficient management of economic FX exposure.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.2
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• pp.239-248
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• 2022

Risks in construction projects are increasing remarkably due to recent changes in the construction environment. Active risk management is required to recognize risks as opportunities. The purpose of this study is to propose a risk management model of the importance determination method through comparative analysis using Kano model, Timko CSC (Customer Satisfaction Coefficient), and ASC (Average Satisfaction Coefficient). Based on previous studies, the validity of risk management factor determination is reviewed through a questionnaire modified Kano model through interviews with working-level workers using the Delphi technique. Through this, a suitable risk management model is presented by selecting key risk management factors recognized by domestic construction project practitioners. As a result of the study, the Kano model developed to verify risk management of construction projects was evaluated to be effective in verifying the risk management of practitioners. It is expected that the Kano model presented in this study will be actively used to verify the importance of risk management for construction projects.

• The Korean Journal of Community Living Science
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• v.15 no.2
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• pp.167-177
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• 2004

The number of foodborne salmonellosis was estimated by using microbial risk assessment(MRA) methodology and the possibility of application was studied through comparison with previous results. The contamination levels of Salmonella sp. were estimated by using published domestic studies(1997∼2000) and monitoring data (1999∼2001) from food-safety related institutes. Data on food consumption came from the 2001 National Health and Nutrition Survey, and dose-response models from studies in other countries. Simulation results showed that there were 753,368 cases of salmonellosis in Korea in 1 year, which is about 115 times that reported in previous years and lower than the WHO's estimation increase. From these results, microbial risk assessment is likely to be available for estimation of the number of foodborne illnesses and determination of the order of priority in food-safety management. Butthe verification methods are not established and most of the data on contamination levels of foodborne bacteria, food consumption, and dose-response relationships have not been established. In addition, the actual conditions of circulation, storage and cooking must be studied further.

• Journal of Korea Water Resources Association
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• v.55 no.spc1
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• pp.1167-1175
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• 2022

In this study, management index method has been developed to estimate the level of deterioration, applied to Cheongju city, and compared with the previous estimation methods of deterioration level of water distribution system. From the results, distribution systems of Yullyang, Naedeok1 and Yongam2 are found to be seriously deteriorated. And it was also found that probability of pipe breakage was estimated as 3.21%, 4.64% which is highest level at the steel pipe of 200 mm and 300 mm diameter. It was found that risk degree was estimated as 0.2609, 0.2644 by using management index method in Naedeok1 which is the most dangerous distribution system in the city. It was also found that results of risk analysis by management index method have been similar with the results of safety analysis by reliability method and indirect estimation method of deterioration level. Therefore, newly developed management index method can be applied and may be useful to the estimation of deterioration level for the future maintenance and management of water distribution system.

• Communications for Statistical Applications and Methods
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• v.26 no.5
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• pp.445-461
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• 2019

It is possible that data are not always fitted with sufficient precision by the existing distributions; therefore this article presents a methodology that enables the use of families of asymmetric distributions as alternative probabilistic models for survival analysis, with censorship on the right, different from those usually studied (the Exponential, Gamma, Weibull, and Lognormal distributions). We use a more flexible parametric model in terms of density behavior, assuming that data can be fit by a distribution of stable distribution families considered unconventional in the analyses of survival data that are appropriate when extreme values occur, with small probabilities that should not be ignored. In the methodology, the determination of the analytical expression of the risk function h(t) of the $L{\acute{e}}vy$ distribution is included, as it is not usually reported in the literature. A simulation was conducted to evaluate the performance of the candidate distribution when modeling survival times, including the estimation of parameters via the maximum likelihood method, survival function ${\hat{S}}$(t) and Kaplan-Meier estimator. The obtained estimates did not exhibit significant changes for different sample sizes and censorship fractions in the sample. To illustrate the usefulness of the proposed methodology, an application with real data, regarding the survival times of patients with colon cancer, was considered.

• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.444-456
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• 2022

Purpose: Laboratories require Preliminary Risk Analysis of Hazard Factors, but there are many laboratories that do not. For the purpose of securing the safety of the laboratory, it is intended to find improvements so that the Risk Assessment can be easily applied. Method: Research papers and data from the Laboratory Safety Management Survey Report by the Ministry of Science and ICT were used. The study was conducted by comparing Preliminary Risk Analysis of Hazard Factors and Risk Assessment under the Occopational Safety and Health Act. Result: A technique for Risk Assessment of a laboratory was proposed. When Risk Assessment of the laboratory, a method was proposed to estimate the size of the possibility(frequency) and severity(intensity). Conclusion: For easy application in the laboratory, a checklist-type Risk Assessment technique was presented and actual evaluation was conducted. It is expected that the laboratory will improve through Risk Assessment to help prevent safety accidents.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.495-504
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• 2009

As the Reliability Centered Maintenance(RCM) is being studied, maintenance tasks can be performed effectively through the Risk Priority Number(RPN) evaluation about the components in the system. The RPN is usually calculated through arithmetical operations of three values, Severity, Occurrence, and Detection for each facility. This RPN provides information that includes risk level of the facility and the priority order of maintenance tasks for facility. However, if there is no sufficient historical failure data, it is difficult to calculate the RPN. In this case, historical failure data from other sources can be used and apply this data to korean railway system. In this paper, it is proposed that a new methodology to model the failure rate as a fuzzy membership function. This method is based on failure data from other sources by means of the fuzzy theory and the expert opinion system. And considering assessment tendency of each expert, distortions that happened when the failure rate of facilities is estimated were minimized. This results determine Occurrence values of facilities. Taking advantage of this result., the RPN can be calculated with Severity and Detection of facilities by using the fuzzy operation. The proposed method is applied the rail-way power substation.

• Journal of Integrative Natural Science
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• v.4 no.3
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• pp.238-242
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• 2011

For any pattern matching based algorithm in WLAN environment, the characteristics of signal to noise ratio(SNR) to multiple access points(APs) are utilized to establish database in the training phase, and in the estimation phase, the actual two dimensional coordinates of mobile unit(MU) are estimated based on the comparison between the new recorded SNR and fingerprints stored in database. The system that uses the artificial neural network(ANN) falls in a local minima when it learns many nonlinear data, and its classification accuracy ratio becomes low. To make up for this risk, the SVM/ANN hybrid algorithm is proposed in this paper. The proposed algorithm is the method that ANN learns selectively after clustering the SNR data by SVM, then more improved performance estimation can be obtained than using ANN only and The proposed algorithm can make the higher classification accuracy by decreasing the nonlinearity of the massive data during the training procedure. Experimental results indicate that the proposed SVM/ANN hybrid algorithm generally outperforms ANN algorithm.