• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.109.2-110
• /
• 2003

Estrogen is the most important endocrine hormone that has reproduction and physiological process in a number of tissues. However, an excess of estrogen can promotes the growth of hormone-dependent breast cancer. Thus the regulation of estrogen level is important a prevention of estrogen-related cancer. It has been reported that some of flavonoids could inhibit estrogen-dependent cancer. And these compounds are expected as chemopreventive agents on estrogen related disease. (omitted)

• Journal of Korean Society of Transportation
• /
• v.27 no.6
• /
• pp.147-156
• /
• 2009

We present a methodology for modeling and solving the transit frequency design problem with variable demand. The problem is described as a bi-level model based on a non-cooperative Stackelberg game. The upper-level operator problem is formulated as a non-linear optimization model to minimize net cost, which includes operating cost, travel cost and revenue, with fleet size and frequency constraints. The lower-level user problem is formulated as a capacity-constrained stochastic user equilibrium assignment model with variable demand, considering transfer delay between transit lines. An efficient algorithm is also presented for solving the proposed model. The upper-level model is solved by a gradient projection method, and the lower-level model is solved by an existing iterative balancing method. An application of the proposed model and algorithm is presented using a small test network. The results of this application show that the proposed algorithm converges well to an optimal point. The methodology of this study is expected to contribute to form a theoretical basis for diagnosing the problems of current transit systems and for improving its operational efficiency to increase the demand as well as the level of service.

• Korean Journal of Veterinary Research
• /
• v.47 no.4
• /
• pp.417-423
• /
• 2007

Serological surveillance programs in animal populations are becoming increasingly important to estimate prevalence of a specific disease and subsequently to document disease-free status in a region or a country. For these purposes, the programs need to be based on both theoretical and economical aspects from the designing phase. From Aujeszky's disease (AD)-eradication program point of view, group of animals (aggregates, herds) not individual animal is the more important sampling unit of concern. In this study the authors therefore attempted to compute an appropriate sample size tailored to a current surveillance program against AD, assuming that the goal of this program is either herd-level prevalence estimation or documentation of AD-freedom. For prevalence estimation, assuming a finite population with imperfect sensitivity (Se) and specificity (Sp) of ELISA kit for AD diagnosis, the number of herds present, expected herd prevalence, and desired accuracy for a certain level of confidence, sample size was estimated at herd-level in the first stage and individual animal-level in the second stage. A two-stage sampling design was used to calculate a sample size to indicate AD-freedom. In this instance, the computation was based on the possible detection of a predetermined prevalence at a certain herd-level Se and Sp. This study indicated that the sample size varied with predetermined confidence, tolerance, Se and Sp at herd- and animal-level, and within- and among-herd prevalence. In general, smaller sample size was required to estimate AD prevalence than to document of AD-freedom. Compared to individual-based samples, two-stage sampling strategy requires a larger sample size to show disease-freedom. Statistical considerations including herd-level test characteristics when designing surveillance program also are further discussed.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.40 no.3
• /
• pp.18-26
• /
• 2017

Defense industries which require high reliability need an optimized quality management system with well-planned implementation. And the government should examine the overall status of defense industries, then establish practical policies with a proper support plan in required areas to upgrade the quality management level of manufacturers. Thus, DTaQ developed the model for 2 years from 2014, which specialized in quality management level analysis for defense industries. And a survey has been undertaken with that model by DTaQ and Korea Research Center in 2016. The surveyed companies randomly sampled among those which have more than 30 employees and delivery history over past 3 years, and finally 106 defense industries were selected. This paper present survey method and indexes for survey of defense industry quality management level. The survey was conducted in the order of planning, data collection and data processing, and the validity and reliability of the data were verified to increase objectivity of survey results. The survey contents mainly consist of system quality and management quality. System quality includes Product Development Management, Production Operation Management, supply chain quality management, Safety & Environment Management and Reliability Management, on the other hand, management quality includes Strategic Leadership, Human Resource Management, Customer Market Management and Information & Knowledge Management. Thus this proposes the current overall quality management status of the 106 defense industries and shows level differences by company sizes and manufacturing sectors based on the result of survey. Specifically, this paper enables to track the areas which need prompt government support with the policy directions to make quality management level higher. Therefore, it is expected that this can be used as reference data in establishing quality policies for military supplies in the future.

• Journal of Environmental Science International
• /
• v.24 no.8
• /
• pp.1045-1053
• /
• 2015

This study evaluated the effect of water level of water resources on water quality in Ulsan. Two reservoirs, Sayeon Dam and Hoeya Dam, were selected and water quality of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were analyzed from 2012 to 2014. And the characteristics of precipitation were also analyzed for 70 years (1945~2014) because runoff of non-point pollutant was strongly affected by precipitation. As a result, water deterioration of Sayeon Dam and Hoeya Dam were affected in accordance with lowering water level. For example, the concentrations of COD and TN was negatively correlated with the water level when the water level of Sayeon Dam was gradually decreased in 2013. The TN concentration was increased to 1.432 mg/L from 0.875 mg/L while the lowest water level of Sayeon Dam was recorded 45 m in 2014. Additionally the concentration of COD and TN was sensitively increased with 0.213 mg/L/m and 0.058 mg/L/m on account of non-point pollutant runoff. It is indicated that hereafter a control of non-point pollutant runoff is the critical factors to maintain water resources because the contribution of non-point pollutant is expected to increase due to the frequent heavy rain events. Therefore, it is necessary to map out a specific plan for non-point pollutant control based on analyses of runoff characteristics, water pollution sources and reduction plans in water pollutants and to establish a water modelling and database system as a preventive action plan.

• Journal of Navigation and Port Research
• /
• v.29 no.4
• /
• pp.327-333
• /
• 2005

Sea level (MSL, MHWL, or MLWL) change has been main concern to scientists and engineers and it can be primarily due to both change of climate and vertical movement of land. This paper reports the intensive analysis of the sea level changes and broad discussion of the future at the southwestern coast of Korean peninsula. Regression analysis was conducted to investigate general tendency and periodicity of the sea levels at the six different study sites such as Gunsan-I(inner port), Gunsan-O(outer port), Mokpo, Yeosu, Heuksan and Jeju and the results were compared with global values. Besides the changes of sea levels due to global warming, the influence of the man-made structure such as seadike and seawall was attempted to quantify using the minimization of the Root Mean Square(RMS) error. The results show that it is a general tendency that the values of mean sea level rise at the southwestern coast of Korean Peninsula, especially at Gunsan-I and Jeju, are somewhat larger compared to global average values. There is also some evidence that tidal amplifications are found just after construction of man-made structure at Gunsan-I and Mokpo. However, both sites show different mechanism in relation to tidal choking, tidal flat and river discharge. The impact due to construction of man-made structure is considerably larger at Mokpo site, while the impacts due to man-made structure and the effect of sea level rise are relatively identical at Gunsan-I site. This study is expected to provide some intuition to future design.

• Journal of the Korean Applied Science and Technology
• /
• v.4 no.1
• /
• pp.91-97
• /
• 1987

Because of its more complete hydrolysis and rapid absorption, MCT is expected its usefulness in the diets of patients with malabsorption syndrom. Also, several authors reported that serum cholesterol level was lower after MCT feedings. In this study, rate of each experimental group were fed for 4weeks with 20％ MCT, 20％ corn oil, mixed diet of 10％ MCT and 10％ corn oil, mixed diet of 17％ corn oil and 3％ shortening. After experimental diet, it was measured to growth rate and serum cholesterol, triglyceride and phospholipid level. The results were as follows; 1. The body weight gain was the lowest in MCT group and others were lower than control group. 2. Serum total cholesterol level was the lowest in corn oil group and others were significantly lower than control group. Free cholesterol level was lower in all experimental groups than control group too. 3. Serum HDL-cholesterol level was significantly higher in all experimental groups than control group. 4. The ratio of VLDL, LDL-Cholesterol to HDL-Cholesterol was significantly lower in all experimental groups than control group. 5. Serum triglyceride level was higher in all experimental groups than control group. Serum phospholipid level was significantly in only mixed diet group of corn oil and shortening than control group. 6. The ratio of total cholesterol to phospholipid was significantly lower in corn oil diet group than control group.

• Journal of Korean Society of Transportation
• /
• v.23 no.2
• /
• pp.151-160
• /
• 2005

In case of public transit such as bus system, the probability concept is used to evaluate the Level-of-Service of the operations. And each levels could be classified according to the linear probability value. (TCQSM: Transit Capacity and Quality of Service Manual-2nd Edition, TRB, Washington DC., 2003) In this case, the drivers or passengers wouldn't think that the service level isn't equivalent to the linear probability value. Thus the linear probability value doesn't exactly reflect the service level. This study shows the problems of using the linear probability value in classifying the service level through the case of evaluation of bus operation's punctuality, presented in TCQSM. To make up for the problems of such case, two methodologies are presented in this study. The method of determining Level-of-Service criteria using probability density of headway variation's distribution, presented in this paper, adequately reflects passenger's expected waiting time. According to the application result to real bus operation data, it tis better than the method of TCQSM to evaluate the reliability of bus operations. However further research about the relations between utility difference and passenger feeling of service level in necessary to apply the method that uses the utility function. It remains as the limitation of this paper.

• Journal of Convergence for Information Technology
• /
• v.10 no.12
• /
• pp.191-200
• /
• 2020

This study was conducted to identify the oral health status and management behavior and dental use behavior according to the level of education and income of the elderly, and to present the supporting data to prepare policies and systems for the promotion of elderly oral health. The data survey was conducted on 224 elderly people living in the Daejeon area from August 19, 2019 to October 25, 2019, and the collected data were analyzed by chi-square test and logistic regression analysis. As a result, oral health status and management behavior showed significant differences according to education and income level in denture use, implant use, oral hygiene product use, oral health education experience, and oral health management method. There was a significant difference in dental use behavior according to education and income level, and age, education level, implant use, and the main reasons for dental use were found to be factors affecting dental use. Therefore, it is expected that the quality of life of the elderly's oral health can be improved by preparing an institutional plan at the national that considers education and income level based on this study.

• Journal of Engineering Education Research
• /
• v.26 no.6
• /
• pp.3-18
• /
• 2023

The purpose of this study is to identify the difference between the current retention level and the required level of engineering students' career competency that they think they need based on their perceptions. Ultimately, the results of this study are used as basic data when designing the major/general education program and the curricular/extra-curricular career program. The task of this study is to identify the difference between the current retention level and the required level of engineering students' career competency. And based on this, it is to confirm the educational needs of engineering students for the career competency. For this purpose, literature research on career competency education in universities was reviewed in the theoretical background. Next, previous studies on career competency and sub-competence derived from career competency-related studies and detailed questions were analyzed. Based on this, an initial evaluation tool for career competency of engineering students was developed. Finally, through expert review, a career competency evaluation tool with a total of 43 items in 10 competency groups was developed. A career competency evaluation questionnaire was conducted for 197 engineering students who participated in the 2022 Engineering Education Festa, and as a result of the IPA analysis, 'global competency' was found to be the competency with the largest difference between importance and execution. Next, 'major job competency' and 'career development competency' appeared in order. Reflecting the results of this study, it is expected that mutually organic design of competency-based liberal arts curriculum and major curriculum that can cultivate global competency, major job competency, and career development capability will be carried out through learning activities and field practice.