• 대한교통학회지
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• 제20권5호
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• pp.99-111
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• 2002

전산기술의 발달에 힘입어 근래에 모의실험을 이용한 연속교통류의 미시적 분석이 활발히 수행되고 있고 다양한 모의실험 전산모형이 소개되고 있다. 미시적 연속교통류 전산모의실험은 차량추종모형과 차로변경모형을 적용하여 다양한 운전자들의 차량운행행태를 모사하여 분석하는 실험이다. 전산모형은 난수를 토대로 차량의 자유속도와 초기 발생 차로를 배정하기 때문에 낮은 자유속도를 할당받은 차량이 높은 속도의 차로(예:1차로)로 발생되는 경우가 발생한다. 많은 모의실험모형이 사용하고 있는 차로변경의 가정이 "운전자는 자신이 원하는 속도(자유속도)를 유지한다"는 것이며 그러한 가정만의 적용으로 인해 현실적이지 않은 차로 이용률이 결과되고, 따라서 전산모형을 통한 교통류 흐름분석에 문제를 제공하고 있다. 본 논문에서는 미국 도로국에서 20여년 동안 개발되고 수정되어왔으며 현재 실용적으로 가장 많이 사용되고 있는 Freeway Simulation(FRESIM) 전산모형이 내재한 차로변경모형을 토대로 고속도로 기본구간에서의 선택적 차로변경모형을 제시한다. 제시된 모형에서는 (1)저속의 선행차량이 고속의 후행차량에게 차로를 양보하는 가정이 새롭게 추가되고 (2)FRESIM모형에서 사용하는 상수값을 국내 현장조사를 통하여 도출된 분포식을 통한 값으로 대체하였다. 수집된 자료분석결과 연속 교통류에서의 15% 차두시간은 1.34초이며 차로변경시간은 평균 2.22초인 F분포를 따르고, 자유속도는 정규분포를 따르는 것으로 결과되었다. 모의실험결과 무작위난수를 토대로 배정된 차로로 생성된 차량들이 새롭게 제시된 차로변경모형의 적용으로 현장 차로이용률을 95% 신뢰수준에서 모사하는 것으로 분석되었다.

• KSTLE International Journal
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• 제3권1호
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• pp.1-6
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• 2002

The purpose of this paper is to investigate the effects of design parameters on the friction loss in piston skirt. An analytical model to describe the friction characteristics of piston skirt has been presented, which is based on the secondary motion of piston and mixed lubrication theory, It could be shown that the skirt friction closely depends on the side force acted on the piston pin. The side force is inf1uenced by cylinder pressure at low engine speed, but by inertia force at high engine speed. The usage of extensive skirt area and low weight piston is effective to reduce the friction loss at high speed. The low viscosity oil considerably decreases viscous friction as engine speed increases, but it increases boundary friction at low engine speed. From the parametric study, it is found that the skirt axial profile is the most important design parameter related to the reduction of skirt friction.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 제5회 박판성형 SYMPOSIUM
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• pp.45-48
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• 2006

Recently, the use of tubular hydroforming technology has seen increased usage and increased consideration for wide range of tubular automotive applications. In manufacturing hydroformed parts, bending and pre-forming operations are often required prior to the hydroforming process. Higher bending quality of bent tubes is crucial for the successful hydroforming operation because most of plastic strains and wall thinning at the extrados of bend area occur in the bending operation. Springback is also observed due to elastic recovery of tube material after bending. Proper correction of springback is required not only to well place the bent tube into a hydroforming die cavity but also to avoid pinching when the upper die is brought down to closing position. Therefore, prediction of springback at early development stage is one of the key factors to produce high quality hydroformed parts. In this study, a variety of bending experiments has been carried out to investigate springback amount under change in bending angle and material boosting. Throughout the experimental approach, springback characteristics of bent tubes are quantified according to the change in various bending parameters, and a mathematical model to predict correction amount of springback to a given bend angle is found.

• Journal of the Korean Data and Information Science Society
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• 제24권6호
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• pp.1177-1188
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• 2013

현대 사회는 지식 사회로의 변화가 빠르게 진행되고 있으며, 사회 전반에 걸쳐 성장과 발전을 위한 지식공유의 필요성이 증대되고 있다. 한편 대학에서는 다양한 분야의 지식이 창출되는 반면에 몇몇 문제들에 의해 지식공유가 원활히 이루어지지 않고 있다. 지식공유를 통해 학업성과가 영향을 받는지 확인하기 위하여, 본 연구는 K대학생을 대상으로 정보기술의 활용, 학교의 지원, 소통문화가 지식공유의 매개에 의해서 학업성과에 미치는 효과를 실증분석하였다. 설문조사를 통해 요인간의 상호관련성과 영향의 정도를 확인한 결과, 정보기술의 활용, 학교의 지원, 소통문화는 지식공유의 매개에 의해서 학업성과에 영향을 미친다고 할 수 있으며 직접적으로도 학업성과에 영향을 미친다고 할 수 있는 것으로 나타났다.

• 한국주거학회논문집
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• 제8권3호
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• pp.59-66
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• 1997

The purpose of this study is to explore the relationships between the various types of activities occurring in domestic space and the resident's characteristics in Belgium. Data for this study was collected by questionnaires mailed to 133 staff member. both academic and administrative. working at The Free University of Brussels. a university serving the Dutch speaking community in Belgium. General leneal model and Duncan test were used in analyzing the data. The major findings of the study can be summarized as follows: First. families in the life-cycle stage of having no children are more likely to relax and watch T.V. and do housework in the master bedroom than those in the launching stage. Families in the life-cycle stage of elementary school are more likely to eat meals in the kitchen than those in the launching period. Second. families made up two members and under tend to do more housework in the master bedroom than those of three and over. Third. those with aged 30 and under are more likely to relax and watch T.V., and to do housework in the master bedroom than those with aged 51 and over. Forth. the renter status of homeownership tend to more relax and watch T.V., and to do housework in the master bedroom than the owner Fifth. those living with less floor space tend to relax and watch T.V. in the master bedroom more than those with larger residences.

• Asian Journal for Public Opinion Research
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• 제1권2호
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• pp.90-102
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• 2014

By integrating useful insights from social cognitive theory and social capital theory, we aim to develop a model for better understanding people's behaviors related to the use of social networking sites (SNSs) and formalize the role of social capital in individuals' continuous SNS use. Propositions that emphasize the triadic interactive relationships among environmental, personal, and behavioral factors were highlighted in this study. After reviewing previous studies, in this paper we proposed the following: (1) the causation between SNS use and individuals' perceived social capital might be mutual; social capital may not only be the result of media selectivity, but could also be an essential stimulus initiating the start of using SNSs; (2) the influences of SNSs use on the generation of individuals' online social capital might be conditional upon particular patterns of use; (3) both the level of dependence on SNSs and the differentiated patterns of SNSs use vary according to individuals' perceived offline social capital and their personal characteristics, for instance, personality or self-construal, and social anxiety.

• Asian Pacific Journal of Cancer Prevention
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• 제17권1호
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• pp.347-352
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• 2016

Background: This study used receiver operating characteristic curve to analyze Surveillance, Epidemiology and End Results (SEER) adenosquamous carcinoma data to identify predictive models and potential disparities in outcome. Materials and Methods: This study analyzed socio-economic, staging and treatment factors available in the SEER database for adenosquamous carcinoma. For the risk modeling, each factor was fitted by a generalized linear model to predict the cause specific survival. An area under the receiver operating characteristic curve (ROC) was computed. Similar strata were combined to construct the most parsimonious models. Results: A total of 20,712 patients diagnosed from 1973 to 2009 were included in this study. The mean follow up time (S.D.) was 54.2 (78.4) months. Some 2/3 of the patients were female. The mean (S.D.) age was 63 (13.8) years. SEER stage was the most predictive factor of outcome (ROC area of 0.71). 13.9% of the patients were un-staged and had risk of cause specific death of 61.3% that was higher than the 45.3% risk for the regional disease and lower than the 70.3% for metastatic disease. Sex, site, radiotherapy, and surgery had ROC areas of about 0.55-0.65. Rural residence and race contributed to socioeconomic disparity for treatment outcome. Radiotherapy was underused even with localized and regional stages when the intent was curative. This under use was most pronounced in older patients. Conclusions: Anatomic stage was predictive and useful in treatment selection. Under-staging may have contributed to poor outcome.

• Asian Pacific Journal of Cancer Prevention
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• 제17권1호
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• pp.353-356
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• 2016

Background: This study used receiver operating characteristic curve to analyze Surveillance, Epidemiology and End Results (SEER) for glassy cell carcinoma data to identify predictive models and potential disparities in outcome. Materials and Methods: This study analyzed socio-economic, staging and treatment factors. For risk modeling, each factor was fitted by a generalized linear model to predict the cause specific survival. Area under the receiver operating characteristic curves (ROCs) were computed. Similar strata were combined to construct the most parsimonious models. A random sampling algorithm was used to estimate modeling errors. Risk of glassy cell carcinoma death was computed for the predictors for comparison. Results: There were 79 patients included in this study. The mean follow up time (S.D.) was 37 (32.8) months. Female patients outnumbered males 4:1. The mean (S.D.) age was 54.4 (19.8) years. SEER stage was the most predictive factor of outcome (ROC area of 0.69). The risks of cause specific death were, respectively, 9.4% for localized, 16.7% for regional, 35% for the un-staged/others category, and 60% for distant disease. After optimization, separation between the regional and unstaged/others category was removed with a higher ROC area of 0.72. Several socio-economic factors had small but measurable effects on outcome. Radiotherapy had not been used in 90% of patients with regional disease. Conclusions: Optimized SEER stage was predictive and useful in treatment selection. Underuse of radiotherapy may have contributed to poor outcome.

• 복식
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• 제53권8호
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• pp.105-120
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• 2003

Despite the creative strengths fashion illustrations, most fashion related advertisements use photographs instead. Furthermore, there is not much study done on the effects of fashion illustrations. Through this study the authors discover the effectiveness of fashion related magazine advertisements using fashion illustrations by looking into the level of recognition due to interaction effects between advertisements using photographs and advertisements using fashion illustrations. This study, however, does not focus on comparing the different levels of recognition effect between photographs and fashion illustrations. After a literature review of magazines with high rank subscriptions, an experiments was conducted. A booklet was made using 16 fashion illustration advertisements and 16 photograph advertisements all designed to control variables other than advertisement type. Then a survey was taken using the booklet to measure the recognition levels of the different types of advertisements. Through an ANOVA test of the 2 ${\times}$ 3 factorial designed model the authors derived results implying that interaction effects do exist between the different types of advertisements. In the environment where advertisements using photographs dominate, advertisements using fashion illustrations can effectively be recognised by the consumers. Through this study, the authors wish to give guidance to decision makers in the fashion industry related to the type of printed advertisement they should seek.

• 한국수산과학회지
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• 제51권3호
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• pp.305-312
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• 2018

This study was carried out to investigate euphausiid abundance in an acoustic survey from March 2010 to July 2010 to suggest reasonable usage and management of the euphausiid Euphausia pacifica in the coastal area of Guryongpo Pohang. The acoustic data were analyzed by the 2-frequency difference method and the distorted wave born approximation acoustical theoretical model, which is used for organisms of weak target strength with small scatter, such as euphausiid scatter, among other marine organisms. The distribution and monthly density of euphausiids were estimated in the survey area. The results show that the volume back scattering strength frequency difference for euphausiid was 13.91-7.6 dB, and their monthly averag density was $28.2g/m^2$.