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

• Journal of the Korean Society of Safety
• /
• v.22 no.5
• /
• pp.71-76
• /
• 2007

Failures of equipments for train control systems are linked directly to extensive damages of human lives or financial losses from the increasing uses of train control equipments utilizing computers. Then safety activities for assuring safety and reliability are needed during the system life-cycle. Risk analysis is important phase to increase safety from determining the risk presented by the identified hazard. In this paper, we investigated several methods for risk estimation of safety activities, and then we drew a comparison between original methods to suggest optimized one in the application to train control systems. In the result of the comparison, we had plan to propose the risk analysis method called Best-Practice(BP) risk method combining advantages of the qualitative and the quantitative analysis. In addition, we attempted to apply the BP-risk method to domestic train control systems handling in Korea.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.04a
• /
• pp.458-461
• /
• 2008

The primary objective of this study is to provide simple analytical tools to estimate dynamic characteristics of steel framed floor system in hospital building for vibration serviceability due to human activities, bogie, medical equipment. and so on. In order to evaluate the dynamic characteristics and vibration levels according to steel framed floor system, we had executed impact test and measurement on steel structure floor system in various hospital buildings. But perhaps most importantly, how to make the most of deduced design factor for design of hospital building. therefore we presented the access method such as the three-dimensional F.E. numerical analysis on the basis of the design drawing, and the properties of all floors for estimation of vibration level in hospital building.

• International Journal of Quality Innovation
• /
• v.2 no.1
• /
• pp.117-128
• /
• 2001

It is widely recognized that ISO 9000 certification bring some profits, such as enhancement of quality system and some concerns. Since one of the major concerns is cost for certification, this paper considers the cost for ISO 9000 certification in Japanese companies through review some winning reports and case studies. Specifically, a model that describes the certification activities and their cost is derived through reviewing some winning reports in order to give a framework of cost estimation. Based on the model, we estimate the certification cost in an electric division of a company through an interview survey. Furthermore, we focused on the cost for promotion and administration as a cost for the sake only certification, because these activities will not be needed if a company does not implement ISO certification. It is concluded that this cost may vary approximately 300,000-700,000 (US$) per certification by the interview and telephone surveys to Japanese steel companies.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.20 no.2
• /
• pp.1-17
• /
• 1992

This study was carried out to estimate the recreation carrying capacity of lawn areas in parks. Recreation carrying capacity in this study is composed of two parts, ecological carrying capacity and psychological carrying capacity. As the second part, this apper deals with the estimation of ecological carrying capacity based on user behavior. The study sites were located at Bomun Resort Complex in Kyungju, Korea. And the major species of the lawn areas was Zoysia japonica. The major results ar summarized as follows: 1. The mean numbers of user for the investigation days of peak season, were estimated as 792 people for the lawn area of Doturag World, and 588 people for Seorabul Plaza. The mean use time by user were 163 minutes and 197 minutes for each site. The weighted mean use time by each activity type(passive, active, and strolling) were estimated as 85 minutes, 45 minutes, and 50 minutes, respectively. 2. Forty kinds of diverse active recreation activities were classified into six types of activity categories. Male adults preferred "sports type" activities, whereas female adults and juveniles preferred "play type" activities. 3. Ecological carrying capacity for each level was estimated as 40.7㎡/man for optimum carrying capacity. And these values were calculated on the basis of total treading areas and treading time criteria for each carrying capacity level.

• KIEAE Journal
• /
• v.16 no.3
• /
• pp.129-135
• /
• 2016

Purpose: Building figuration is imperative to perceive the its value, environmental clean status and form. Therefore, maintenance activities of the building exterior are required to keep the housing condition and value. Each household should pay the repair cost which is brought out in the future. For this repair cost, the estimation model would needed to forecast and provide the required cost. This study aimed at providing the estimation model of the repair cost, using the repair survey data between the 2011 and 2014 in Seoul. Method: For these, it took various estimation function of repair cost such as 1st function, inverse function and so on. These above functions would be applied into the building exterior and outdoor facilities which figure the building shape and characteristics. Result: Results of this study are shown ; First, among 11 estimation models, the power function has a better statistics and goodness-of-fit than any other models. Second, the estimation model with a variable of household has a pattern in upward to the right. On the contrary, the model with management area is little downward to the right. Both of them are depended on the estimated parameter of the power function and the parameter smaller than 1.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.1
• /
• pp.31.1-31.1
• /
• 2012

I will report recent progress in understanding properties of stellar and interstellar components of the Milky Way Galaxy on the two extremes - ongoing star formation activities in the Galactic center and stellar relics in the halo. Properties of the interstellar medium in the Galactic center and their relationship with star formation activities will be discussed based on by far the largest mid-IR spectroscopic data set in this region. Correlations between stellar kinematics and metallicities in the halo will be presented, along with a discussion on the estimation of fundamental stellar parameters from a set of empirically calibrated isochrones.

• Environmental and Resource Economics Review
• /
• v.14 no.4
• /
• pp.893-921
• /
• 2005

In this study, we try to find out the effect of private companies' environmental protection activities on the labor demand of companies in Korea manufacturing industries with empirical practice from 1992 to 2002. One of the main difficulties in this empirical work is to identify the effect of environmental protection activities on the labor demand, because the effect can be mixed with the effect of traditional production technologies on the labor demand. We follow the suggestion of Morgenstern et al. (2002) to identify the effect but which is not enough because of endogeneity between the production technology improvement and pollution reduction. So we propose a Fixed-effect Instrumental Variable estimation method as an estimation strategy. The estimation results support the positive relationship between the labor demand increase and the increase in pollution abatement costs. Therefore, we can conclude that the environmental protection activites of Korea manufacturing industries from 1992 to 2002 can help job creation without making a big burden for business activities when we consider the share of pollution abatement costs among total production costs is around 1% during that time.

• Journal of the Korea Safety Management & Science
• /
• v.14 no.3
• /
• pp.127-134
• /
• 2012

Plant safety management that is enforcing introducing more than 95% in domestic manufacturing industry is using total plant efficiency by the evaluation index, and as a result, can see a lot of examples that plant productivity, economy and safety is increased. The efficient safety estimation for a business should analyze an accident data by considering every possible and potential factor. This study's purpose centers plant safety management activities that is management system for plant production and safety efficiency's maximization, plant evaluation system that plant safety management activities factor(reliability, maitainability, safety, service quality) that is enforcing in manufacturing industry can develop evaluation model that can evaluate qualitative activities by quantitative activities in process that maximize plant safety management wishes to do design.

• Journal of Information Technology Services
• /
• v.14 no.3
• /
• pp.67-84
• /
• 2015

Software is more diverse and complex and the level of importance for the maintenance of application software to securely operate software is also gradually increasing in proportion. The calculation method for maintenance cost of application software applied in Korea public enterprises is involved in the range of 10 to 15% of development cost, depending on the Software Project Cost Estimation Guide. Moreover, as most software maintenance cost estimation procedures do not take into consideration of the risk factors related of maintenance, it can be seen as a main cause for the occurrence of maintenance related accidents. This study proposes a maintenance cost estimate model that takes into consideration of the risks related to the software maintenance activities to improve and resolve issues arising from the estimation of maintenance cost. In doing so, maintenance risk factors are analyzed and a risk index is derived through the analysis of risk levels based on the risk factors. Based on such analysis, a maintenance cost estimate method which reflects the maintenance risk index was established.