• Journal of Biosystems Engineering
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• 제42권4호
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• pp.242-250
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• 2017

Purpose: This study was conducted to determine the appropriate operating conditions through a factorial experiment for the secondary separating part of the self-propelled pepper harvester. Methods: An experimental setup that simulates the secondary separating part of the self-propelled pepper harvester was organized. Test samples were classified into three types according to the number of peppers on a stem, and 12 sets were prepared for each type. Among the operating conditions of the secondary separating part, the rotational speed of drum B (four levels), radial clearance between drums and cylindrical teeth (three levels), and speed ratio between the three drums (two levels) were set as the test factors, and tests were repeated three times for different levels of each factor. The appropriate operating conditions were determined by analyzing the separation ratio and damage ratio of the peppers collected through the secondary separating part. Results: The test factors changed the overall separation ratio and overall damage ratio in similar trends. In other words, the conditions that caused high overall separation ratios also exhibited high overall damage ratios. Owing to the high overall damage ratio in the condition with the highest overall separation ratio, the operating conditions should be selected considering both ratios. Conclusions: When the condition with more than 60% of overall separation ratio and less than 15% of overall damage ratio was considered as the appropriate operating condition, 70 rpm of the rotational speed of drum B, 5 mm of the radial clearance between drums and cylindrical teeth, and 7:3:5 for the speed ratio of the three drums A, B, and C should be applied for the secondary separating part used in this study. Supplementary studies will be required in the future to find optimal operating conditions through the actual field test under further divided test factors.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.5-8
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• 2003

This paper presents a methodology to be able to select an appropriate RP system that suits the end use of a part. Evaluation factors used in process selection include major attributes such as accuracy, roughness, strength, elongation, part cost and build time that greatly affect the performance of RP systems. Crisp values such as accuracy and surface roughness are obtained with a new test part developed. The test part is designed with conjoint analysis to reflect users' preference. The part cost and build time that have approximate ranges due to cost and many variable parameters are presented by linguistic values that can be described with triangular fuzzy numbers. Based on the evaluation values obtained, an appropriate RP process for a specific part application is selected by using the modified TOPSIS(Technique of Order Preference by Similarity to Ideal Solution) method. It uses crisp data as well as linguistic variables, and each weight on the alternatives is assigned by using pair-wise comparison matrix. The ranking order helps the decision making of the selection of RP systems.

• 한국콘텐츠학회논문지
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• 제16권4호
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• pp.418-425
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• 2016

본 논문에서는 지식기반 기법에서 한국어 명사의 의미중의성 해소에 유용한 품사집합을 제시한다. 세종 형태의미분석 말뭉치에서 174,000 문장을 추출하여 테스트 셋으로 이용하고, 표준국어대사전의 뜻풀이와 용례를 이용하여 각 문장의 의미중의성을 해소하였다. 그 결과 전체 테스트 셋의 성능을 가장 좋게하는 15개의 품사집합과 단어별 평균을 가장 높게 하는 17 개의 품사집합이 제시되었다. 실험결과 45 개의 전체 품사집합을 이용하는 것보다 정확도가 최대 12%까지 향상되었다.

• 한국정보과학회논문지:정보통신
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• 제28권2호
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• pp.277-287
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• 2001

통신 프로토콜의 상호운윤성을 시험하기 위한 시험경우를 생성하는 방법론이 논문[1, 2, 3]에서 제안되었고 TCP와 ATM프로토콜에 적용되었다. 이들 방법론으로 생성된 시험경우는 제어부분만을 고려하고 있다. 그러나 실제 시험에 있었서는 데이터를 고려하여야 하며 완전한 시험이 되기 위해서는 이들 변수들이 가질 수 있는 모든 값에 대한 시험을 거쳐야 하지만 이것은 현실적으로 불가능하다. 본 논문에서는 데이터를 포함하는 시험을 하기 위하여 논문[1]에서 도출한 시험경우에 제어 부분과 데이터 부분을 동시에 고려하여 TCP의 연결설정 절차에 대한 시험경우를 도출한다. 이 과정에서 시험경우의 수가 너무 커지는 것을 피하기 위해 최소의 실험횟수로 최대의 정보를 얻을 수 있도록 실험계획법을 이용한다. 실험계획법은 적합성 시험에는 적용되었지만 아직 상호운용성 시험에는 적용되지 않았다. 이 방법을 통해 데이터 부분을 포함하는 상호운용성 시험경우를 생성하고 시험의 검출력을 유지하면서 최소화된 시험경우로 상호운용성 시험을 할 수 있는 기능성을 보인다

• 방송공학회논문지
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• 제15권1호
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• pp.29-39
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• 2010

본 논문에서는 ATSC (Advanced Television Systems Committee) 지상파 디지털 TV 방송 방식에서의 분산 주파수 망(distributed frequency network)을 위해 개발된 분산중계기(Distributed Translator: DTxR)에 대한 실험실 테스트 결과를 기술하고, 그 결과를 분석한다. DTxR 실험실 테스트는 수신부 테스트와 송신부 테스트로 구분된다. DTxR 수신부 테스트는 dynamic range, 랜덤 잡음, 단일 에코, 인접채널 신호의 간섭 테스트 등을 포함하고, DTxR 송신부 테스트는 출력신호의 품질(대역외 방사, 송신 품질, 위상잡음), 출력신호들의 주파수 일치, TxID (Transmitter Identification) 신호가 상용 수신기에 미치는 영향 평가 등을 포함한다. 실험실 테스트 결과에 의하면, DTxR 수신부는 0~17 us 범위 내의 평균 -2.5 dB의 단일 에코 신호를 제거하며, 랜덤 잡음에 대한 TOV (Threshold of Visibility)는 평균 17.5 dB이다. 또한, DTxR 송신부 출력 신호는 미국의 FCC (Federal Communications Commission) 규격을 만족하며, DTxR 출력신호들의 주파수 차이는 0.001 Hz 보다 작다.

• 한국산학기술학회논문지
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• 제17권7호
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• pp.123-133
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• 2016

본 연구의 목적은 간호대학생들의 아르바이트 실태를 파악하고, 아르바이트 경험의 다양한 요인들 중 간호사에게 필요한 의사소통능력, 자기 효능감, 사회적 기술에 미치는 효과와 요인과의 상관관계를 파악하고자 하였다. 본 연구의 대상은 S, B, G시 소재의 간호대학에 재학 중인 대학생 362명을 참여자로 선정하였다. 자료분석방법으로 대상자의 아르바이트 경험유무와 일반적 특성과의 관계는 Chi-square(${\chi}^2$) test, Fisher's exact test검정으로, 일반적 특성에 따른 의사소통능력, 자기 효능감, 사회적 기술척도의 집단 간의 차이는 t-test, Analys of variance(ANOVA)검정으로 분석하였다. 연구에서 나타난 결과는 간호대학생의 91.7%가 아르바이트를 경험하였으며, 8.3%는 아르바이트를 경험하지 않았다. 아르바이트 경험유무와 일반적 특성과의 관련성에서 경제적 수준이 낮을수록 아르바이트를 경험하는 것으로 나타났다. 아르바이트를 하게 된 요인으로는 '용돈 마련'이 77.9%로 가장 높았으며, 아르바이트 분류항목에서 '카운터 및 서빙' 부분이 62.2%로 가장 많았다. 아르바이트 경험에 따른 간호대학생의 의사소통능력, 자기 효능감, 사회적 기술의 정도와 관련하여 아르바이트 시작시기와 통계적으로 유의한 차이가 있는 것으로 나타났다. 특히 중학교 시기에 아르바이트를 경험한 학생들의 의사소통능력, 사회적 기술 능력이 고등학교 시기 이후에 아르바이트를 경험한 학생들에 비해 낮은 점수를 보여주었다. 본 연구결과를 토대로 간호대학생의 아르바이트 경험에 대한 강점을 파악하고 이를 적용할 수 있도록 하는 지속적인 연구가 요구된다.

• 통합자연과학논문집
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• 제5권4호
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• pp.241-245
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• 2012

Categorical data collected based on complex sample design is not proper for the standard Pearson multinomial-based chi-squared test because the observations are not independent and identically distributed. This study investigates effects of bias of point estimator of population proportion and its variance estimator to the standard Pearson chi-squared test statistics when the sample is collected based on complex sampling scheme. This study examines the effect under two population homogeneity test. The standard Pearson test statistic can be partitioned into two parts; the first part is the weighted sum of ${\chi}^2_1$ with eigenvalues of design matrix as their weights, and the additional second part which is added due to the biases of the point estimator and its variance estimator. Our empirical analysis shows that even though the bias of point estimator is small, Pearson test statistic is very much inflated due to underestimate the variance of point estimator. In the connection of design-based variance estimator and its design matrix, the bigger the average of eigenvalues of design matrix is, the larger relative size of which the first component part to Pearson test statistic is taking.

• 한국항공운항학회지
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• 제25권1호
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• pp.35-39
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• 2017

The engine is the most significant and essential part of the aircraft. As a result, systematical handling in the aircraft development stage is required from engine design to implementation to the full-scale airframe. This survey demonstrates the procedures demanded by the KAS 23 Civil Aircraft to acquire the engine Type Certification and the flight test procedures for ensuring the operational stability. Surveys were conducted on domestic and international aircraft engine certifications, technical regulations and documentations related to the Means of Compliance for flight test development stage. In addition, organized reference items that should be considered for the certification of engine flight test procedures were reviewed based on the KC-100.

• 한국농공학회논문집
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• 제48권4호
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• pp.33-40
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• 2006

In present study, the principal stress condition needed to conduct cubical large-scale triaxial test which can reflect three dimensional stress condition (or plain strain condition) in a dam was investigated by performing model test and numerical analysis and the principal stress ratio varying with the height of CFRD was examined. Also, the principal stress ratio in CFRD body was investigated from the monitoring results of horizontal and vertical earth pressure gages, installed in the center zone and lower part of transition zone of the dam body, respectively, in order to consider the principal stress condition in the large-scale triaxial test to model the behavior of CFRD. The result of the study indicated that the principal stress ratio decreased gradually from the lower to the upper part in the dam body for its center axis and was about 0.5 and 0.2 in the lower and upper part, respectively.

• 영재교육연구
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• 제8권2호
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• pp.69-89
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• 1998

The purpose of this study is to develop a test which can be used in identification of the gifted students in the area of mathematics. This study was carried out for two years from 1996. Mathematical giftedness is, in this study, regarded as a result of interaction of mathematical thinking ability, mathematical creativity, mathematical task committment, background knowledge. This study presumed that mathematical thinking ability is composed of seven thinking abilities: intuitive insights, ability for information organization, ability for visualization, ability for mathematical abstraction, inferential thinking ability(both inductive and deductive thinking abilities), generalization and application ability, and reflective thinking. This study also presupposed that mathematical creativity is composed of 3 characteristics: fluency, flexibility, originality. The test for mathematical creative problem solving ability was developed for primary, middle, and high school students. The test is composed of two parts: the first part is concentrated more on divergent thinking, while the second part is more on convergent thinking. The major targets of the test were the students whose achievement level in mathematics belong to top 15~20% in each school. The goodness of the test was examined in the aspects of reliability, validity, difficulty, and discrimination power. Cronbach $\alpha$ was in the range of .60~.75, suggesting that the test is fairly reliable. The validity of the test was examined through the correlation among the test results for mathematical creative problem solving ability, I. Q., and academic achievement scores in mathematics and through the correlation between the scores in the first part and the scores in the second part of the test for mathematical creative problem solving ability. The test was found to be very difficult for the subjects. However, the discrimination power of the test was at the acceptable level.