• 한국지반신소재학회논문집
• /
• 제16권2호
• /
• pp.1-10
• /
• 2017

본 연구에서는 지오그리드로 보강된 사각형 복합 인공어초의 침하 및 세굴 특성을 알아보기 위해 대형 수조 침하 실험, 2차원 흐름 수조 실험 등 다양한 실내 실험을 수행하였다. 또한 인공어초의 각 배치 형태(배치도 A; 나란히 배치된 형태, 배치도 B; 지그재그로 배치된 형태)에 따른 세굴 특성을 알아보기 위해 수치해석을 수행하였다. 실내 실험 결과 무보강된 인공어초에 비해 지오그리드가 보강된 인공어초의 침하 및 세굴 깊이가 크게 저감되었다. 인공어초 배치 형태에 따른 세굴 특성을 알아보기 위한 흐름 수조 실험과 수치해석을 수행한 결과 배치도 A의 세굴 깊이와 유속 벡터는 배치도 B보다 더 감소하는 경향을 보였다.

• 한국터널지하공간학회 논문집
• /
• 제11권3호
• /
• pp.213-221
• /
• 2009

본 논문은 콘크리트 라이닝의 배면공동 현상, 초기 균열 등과 같은 콘크리트 라이닝 타설시 문제점들을 해결하기 위해 개선 방안을 제시하고 이를 단면크기의 변화에 따른 영향을 연구하였다. 연구를 수행하기 위해 초기 균열 형태와 발생 원인에 대한 분석을 실시하였으며 균열발생 최소화를 위한 개선된 타설 방안을 제시하였다. 제시한 타설 방안의 효율성 및 터널 단면크기에 따른 영향을 확인하기 위하여 기존의 1/20 축소모형실험 및 1/7 축소모형실험을 실시하여 타설율을 비교 분석하였다. 이에 따른 실험 결과는 기존의 타설 방안의 경우 1/20 축소모형실험 보다 1/7 축소모형실험의 타설율이 증가하여 차이를 보였지만 개선된 타설 방안의 경우 유사한 타설율을 나타내 2가지 실험 모두 신뢰성을 갖는 것으로 판단된다.

• Smart Structures and Systems
• /
• 제4권4호
• /
• pp.465-492
• /
• 2008

Proper pretest planning is a vital component of any successful vibration test on engineering structures. The most important issue in dynamic testing of many engineering structures is arriving at the number and optimal placement of sensors. The sensors must be placed on the structure in such a way that all the important dynamic behaviour of a structural system is captured during the course of the test with sufficient accuracy so that the information can be effectively utilised for structural parameter identification or health monitoring. Several optimal sensor placement (OSP) techniques are proposed in the literature and each of these methods have been evaluated with respect to a specific problem encountered in various engineering disciplines like aerospace, civil, mechanical engineering, etc. In the present work, we propose to perform a detailed characteristic evaluation of some selective popular OSP techniques with respect to their application to practical civil engineering problems. Numerical experiments carried out in the paper on various practical civil engineering structures indicate that effective independence (EFI) method is more consistent when compared to all other sensor placement techniques.

• 한국도로학회논문집
• /
• 제20권1호
• /
• pp.97-105
• /
• 2018

PURPOSES : Asphalt concrete pavement is damaged by various causes such as traffic and environmental loads. The distressed pavement should be maintained by various methods to provide a comfortable and safe pavement for the driver. This study evaluates the effect of adding a mixing procedure to enhance the mixture quality in the hot in-placement recycled asphalt pavement method, which is an asphalt-pavement maintenance method. METHODS : Various test methods such as Marshall stability and dynamic stability, were employed to estimate the recycled asphalt mixture with and without an additional mixing, using the hot in-placement recycled asphalt pavement method. RESULTS : The mixture samples used in this study were taken before and after the addition of the mixer in the hot in-placement recycled asphalt pavement method (HIR) at field construction sites in GongJu and JinJu in South Korea. The test results of both mixtures satisfied the asphalt-mixture standard specifications. CONCLUSIONS : This study confirmed that adding a mixer in the HIR method results in a well-mixed new asphalt mixture, rejuvenator, and reclaimed asphalt mixture.

• 영어어문교육
• /
• 제12권3호
• /
• pp.147-166
• /
• 2006

This study investigates the effect of misplacement in a written Computer-delivered ESL Placement Test (CEPT) context. The study aims to address the following two research questions: a) which scoring rubric features cause the misplacement of ESL learner's writing scores? and b) which scoring rubric features improve ESL learner's writing scores? Thirty-four international examinees took the test and participated in surveys at the University of Illinois. Twelve examinees of them attended the CEPT workshop test. In the workshop test, they carried out self-evaluation on their first essays using a scoring rubric and compared with expert raters' results. After the workshop, the examinees responded to a survey and interview. For the first research question, the results of the survey and interview addressed that the majority disagreed with the raters' rating results. The self-evaluation results also indicated that their misunderstanding of organization feature caused the misplacement. For the second question, the CEPT workshop scores were improved due to the score improvement in the organization feature while the contribution of other features to the total scores was little. Most of the examinees pointed out that a lesson on the scoring rubric enhanced their understanding of the writing features of the rubric so that their placement scores were generally improved.

• 대한전기학회논문지:전력기술부문A
• /
• 제54권12호
• /
• pp.567-572
• /
• 2005

This paper presents a scheme to design optimal placement of phase-shifting transformers for power system congestion problems. A good design of phase-shifting transformers placement can improve total transfer capability in interconnected systems. In order to find the optimal placement of phase-shifting transformers, the power flows of the interesting transmission lines are evaluated using sequential quadratic programming technique. This algorithm considers power balance equations and security constraints such as voltage magnitudes and transmission line capacities. The proposed scheme is tested in 10 machines 39 buses and IEEE 57 buses systems. Test result shows that the proposed method can find the optimal placement of phase-shifting transformers to solver power system congestion problems.

• 공학교육연구
• /
• 제16권4호
• /
• pp.15-20
• /
• 2013

The result of the English test for freshmen showed wide difference in the ability of students, which means the graded class is strongly required. This paper describes the case study about the graded English class that was carried out for the freshman. Every freshman must take an English placement test from problems bank and were classified according to the result of the test. In order to resolve the dissatisfaction of the high level students, the statutes of my university for credit were modified. In order to analyze the effect of the graded class, evaluation test using similar problems was carried out at the end of the semester. The effect of the graded class was analyzed by using the paired samples t-test method and there was a meaningful performance improvement at the average score. Additional improvements in the method of classification and credit granted were made by analyzing the results of the evaluation test and survey.

• 공학교육연구
• /
• 제14권2호
• /
• pp.51-59
• /
• 2011

동일한 대학에 진학한 학생들임에도 불구하고, 학생들에 대한 진단평가의 성적이 매우 넓게 분포되어 있으며, 이는 영어수준별 수업이 필요할 수 있음을 의미한다. 하지만, 치밀한 행정적 준비 없이 영어수준별 수업을 시작하는 것은 많은 시행착오를 낳을 수 있다. 본 논문에서는 지방에 소재하는 이공계 대학의 신입생 대상 영어 수준별 수업 시행의 사례를 통하여, 수준별 수업의 운영전반에 대하여 살펴본다. 특히, 진단평가 계획부터 실행 및 분반, 공동기말고사, 성적산출 방법에 이르기까지의 과정을 차례로 짚어본다. 또한 각 단계별로 요점과 함께 문제점, 개선사항을 알아보며, 궁극적으로 교양 영어교육의 질을 향상시킬 수 있는 방향을 살펴본다.

• Journal of the Korean Data and Information Science Society
• /
• 제24권6호
• /
• pp.1401-1408
• /
• 2013

반복이 있는 랜덤화 블록 계획법에서 우산형 대립가설을 검정하기 위한 비모수 방법에는 Kim과 Kim (1992)이 제안한 방법이 있다. 본 논문에서는 Orban과 Wolfe (1982)가 제안한 위치와 Kim (1999)이 제안한 대조군과 처리군의 방법을 확장하여 랜덤화 블록 계획법에서 우산형 대립가설에서의 검정법을 제안하였다. 또한 여러 분포에 대한 모의실험 통하여 기존의 방법과의 검정력을 비교하였다.

• Human Ecology Research
• /
• 제53권4호
• /
• pp.341-350
• /
• 2015

This study explored the determinant variables influence of Chinese consumers' purchase intention towards products featured in Korean TV dramas vis-$\grave{a}$-vis product placement (PPL). We invited 248 Chinese adult consumers who had watched Korean TV dramas in last twelve months to participate in this survey. Data analyses were conducted by Cronbach's ${\alpha}$ reliability test, confirmatory factor analysis, t -test, analysis of variance and hierarchical multiple regression with SPSS ver. 21.0 and AMOS ver. 21.0. We chose PPL effects, product quality perceptions, and product trust as main independent variables. The empirical analysis results demonstrate that female (versus male) and frequency of (or longer time) watching dramas resulted in higher perceived consumer PPL effects, product quality, trust and purchase intention. The positive effects of the product quality and product trust on purchase intentions were confirmed. There are additional mediation effects of product quality perceptions and trust on the relationship between consumer demographic characteristics (gender), TV drama watching conditions (frequency and time) and purchase intention. This research can help Korean corporations produce effective advertising by indicating how PPL affects Chinese consumer consumption behavior. The results are useful for the Chinese government and consumer organizations to improve the domestic consumption environment by developing effective TV drama PPL policies.