PURPOSES : Traffic congestion on freeway generally occurs when the traffic volume exceeds the road capacity. Most traffic manuals *such as the Korean Highway Capacity Manual) present the highway capacity as approximately 2,000 units/hour. However, in the real world, freeway congestion occurs for various reasons, including unusual driver behaviors, physical road limitations, and large traffic volumes. Thus, the flow rate at a traffic breakdown can have a wide range of volumes. Therefore, using 5-min volume and speed data from the field, this study explores the stochastic features of traffic breakdowns on major urban freeways in Seoul. METHODS : First, a breakdown point is defined by applying a wavelet transform to identify the sharp drop in the speed data near freeway bottlenecks. Second, based on the flow rate at and before a breakpoint, a survival analysis is performed to construct the probability distributions of the traffic breakdown. Log-rank tests are also conducted to verify the similarities of the distributions between freeways. RESULTS : The analysis results confirm the stochastic features of the urban freeways in Seoul. Specifically, the freeways have typical S-shaped distributions of breakdown probabilities. However, the distributions rise steeply (exceeding a 50% of breakdown probability) at flow rates of 1,150 vphpl to 1,700 vphpl; this is lower than the general expectation. CONCLUSIONS : The statistical differences in the probability distributions for freeways indicates that applying a general standard to every urban highway could raise problems. This study has a limitation in identifying the specific causes of traffic congestion owing to the by physical relationships between individual vehicles. An investigation if vehicle trajectory data should be conducted to examine these aspects in further detail.

본 연구는 새만금 간척지에서 방풍시설의 설치에 따른 수림대의 초기 생존율을 분석하기 위하여 생존 분석 기법 중의 하나인 생명표법을 적용하였다. 생명표법은 의학, 사회과학 등 많은 분야에서 활용하고 있는 방법 이며, 본 연구에서는 방풍책의 설치에 따른 초기 수림대 수목의 생존 기간별 생존율, 중위 시간 등을 생명표 를 통해 알아보고, 생존함수 그래프와 위험함수 그래프 그리고 수림대별 비교를 통해 생존율의 차이를 분석 하고자 하였다. 주요 결과로는 곰솔 수림대의 중위 시간은 100% P-tb와 25% P-tb에서는 48.00개월 이었 고, 50% P-tb는 20.85개월로 짧았다. 25% P-tb에서 누적 생존율이 가장 높았으며, 위험률은 50% P-tb가 가장 높았다. 졸참나무 수림대의 경우 모든 수림대에서 중위 시간은 48.00개월 이었으며, 50% P-tb에서 누 적 생존율이 가장 높았고, 위험률은 100% P-tb에서 가장 높았다. 생존율 비교 결과, 곰솔 수림대는 전체적 으로 방풍책의 설치가 생존율에 영향을 미쳤으며, 특히 50% P-tb와 25% P-tb에서 유의미한 차이가 나타났 는데, 25% P-tb가 생존율과 위험률 측면에서 우수한 결과를 나타내었다. 반면에 졸참나무 수림대의 경우 전 체 수림대의 생존율이나 수림대별 생존율은 방풍책의 설치에 영향을 받지 않는 것으로 분석되었다.

Many measurement methods for understanding consumers’ acceptable price range have been developed. Among these, Price Sensitivity Meter (PSM) is one of the most popular. It has been regarded as a convenient research method because of the ease of data collection and data processing. In particular, PSM requires only four questions to determine the price range. Nevertheless, it also has some problems from a theoretical viewpoint. The purpose of the present research is to develop a new price research method for measuring consumers’ acceptable price range. In particular, applying survival analysis to data prepared for PSM, Japanese consumers’ price acceptance ranges for several categories were estimated.

출소 후 바로 범죄를 저질러 삼 개월 만에 다시 시설로 돌아오는 사람도 있고, 삼 년이 지나 재범을 저질러 교도소에 들어오는 범죄자도 있다. 둘 다 재범을 저질렀다는 점에서 동일하나, 분명 정상적인 사회생활을 누린 기간이 다르다는 점에서 두 범죄자의 사회 재적응력이나 재통합 정도는 다르다고 볼 수 있다. 본 연구는 2005년에 출소한 30,224명의 범죄자 자료를 보라미 시스템에서 다운받아, 2011년 5월까지 약 5년간의 재입소율을 생존분석(survival analysis)으로 검토한 연구이다. 출소자들의 재입소에 영향을 주는 요인들이 어떠한 것들이 있는지 살펴보기 위해 본 연구에서는 교정프로그램을 (1)외부접견(귀휴, 체험/견학, 가족만남의날, 접견 포함), (2)교육훈련(교과교육, 직업훈련, 종교활동, 교도작업), (3)의료처우(의무관처방, 자비약품구입) 세 범주로 구분하였고, 종속변수는 재입소까지의 생존기간으로 보았다. 분석 결과, 전체 30,224명의 표본 중 43.5%에 해당하는 13,137명이 2005년 출소 이후 5년 내 다시 범죄를 저질러 시설에 들어온 것으로 나타났다. 이들의 재범 생존기간을 가지고 Cox 회귀분석을 실시한 결과, 외부접견에 해당하는 일부 변수들(체험/견학, 가족만남의날, 접견)이 재복역한 출소자들의 생존기간과 유의미한 양(+)의 관계를 갖는 것으로 나타났다. 또한, 교도작업 등의 일부 변수도 재입소 기간을 지연시키는 긍정적인 양(+)의 영향력을 보이는 것으로 나타났다. 교정시설 내에서 많은 교정프로그램이 운영되고 있지만, 종단적인 차원에서 어떠한 활동들이 가장 출소 후 재범을 지연시키는지 구체적으로 밝혀진 것이 많지 않다. 본 연구 결과가 근거-중심의 교정정책(evidence-based correction)을 수립하는 작은 토대가 되기를 기대한다.

In this study, the contamination levels of total aerobic bacteria, E. coli, total coliform and S. aureus of seasoned dried fishes (SDF) in Korea were investigated. A total of 81 SDF samples were purchased randomly from 28 stores. Contamination range of total aerobic bacteria, total coliform and S. aureus were 150~1,700,000, 10~31,000and 10~220 CFU/g, respectively. E. coli was detected in only one samples in the qualitative test. We have analyzed quantitatively Staphylococcal enterotoxins (SE-type A, C and D) produced by S. aureus contaminated in SDF using a TECRA kit and standard curve. The curve equation was Y = 0.1499 * X + 0.1183 and maximum amount of SEs in SDF was 0.71 ng/ml. Reduction speed of S. aureus in SDF stored at 37 ℃ was the highest among the samples stored for 8 days at different temperature of 7, 18 and 37℃ . On the basis of the results, SDF in Korea can be contaminated by a variety of pathogenic bacteria. Therefore, precautionary measures are necessary for consumer protection, including the improvement of sanitary conditions in the processing plants in Korea.

The environment of automobile industry in the world is rapidly changing. It is changing of high oil price, technology, environment and construction of competition by newly rising an economic district. Automobile company is focusing on three issue because they want to reinforce competition of automobile industry in the world. That is innovation of production profit management through quality management and Lean. Chance of success is separated in R&D, providing distribution, manufacture, distribution, selling in automobile industry. Emphasis on development process, distribution process, manufacture process, circulation and selling process for strengthening the competitiveness and guarantee. In this thesis, we try to analysis the data set period of automobile production by using survival analysis. While using mean comparison of general statistics commit mistakes, survival analysis can used for including censored data in order to heighten analysis efficiency.

Stability of labor market in rural areas was analyzed in this paper with categories of industrial group, employment scale, surviving period, and founder group. The stability of each classified labor market was compared with each other to figure out the stable business class and the unstable class in rural areas. The results of rural areas were compared with those of urban areas. The stability was analyzed with average and coefficient of variation (C.V.) of annual total employees’ change rates. It was revealed that labor market of ‘primary industry’, including agriculture, is unstable. Especially, labor market of ‘mid-size’ and ‘primary industry’ businesses founded as ‘incorporated company’ in rural areas is vulnerable. While labor market of ‘large-size’ is proved to be unstable, it is confirmed that ‘small-size’ or ‘mid-size’, and ‘over-ten-year survived’ businesses have positive contribution to the stable labor market in rural and urban areas. The results show that the stability of labor market is different in each category of business and in each region of rural or urban area. It is expected that the results can be utilized for the regional development policies, of labor and industry part.

The purpose of this study is to analyze willingness to pay (WTP) for organic agricultural products. To accomplish the objective of the study, a consumer survey was conducted. Based on the pilot survey results, parametric survival model was used to analyze the WTP for organic products. The estimation results showed that the WTP for organic agricultural products is 1.4-fold when compared with the conventional products, which is lower than the current price by about 30 percent. The analytical results also showed that such variables as gender, recognitions for organic agricultural products, and consumers’ income have very significant effects on the WTP, and that there are no differences among WTPs by consumption goals. Based on major findings, the most effective countermeasure was suggested for expanding of organic food consumption through the premium reduction of organic products. Reducing the costs of production and distribution, supporting farmers’ income by direct payment system were presented. Furthermore, it is needed to allocate more budget for promoting the consumption and distribution of organic agricultural products, and for enhancing conservation of agricultural environment.