• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 추계학술대회 학술발표 논문집
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• pp.539-544
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• 1998

Generally, welding gap is a serious factor of a falling-off in weld quality among various kind of weld defect. Welding gap is created between two work piece in GMAW(Gas Metal Arc Welding) of horizontal fillet weld because surface of workpiece is not flat by cutting process. In these days, there were many attempts to detect welding gap. though we prevalently use the vision sensor or arc sensor in welding process, it is difficult to detect welding gap for improvement of welding quality. But we have a trouble to find relationship between welding gap and many welding parameters due to non-linearity of welding process. As mentioned about the various difficult problem, we can detect welding gap precisely using neural networks which are able to model non-linear function. Also, this paper was proposed real-time monitoring of weld bead shape to find effect of welding gap and to estimate weld quality. Monitoring of weld bead shape examined the correlation of welding parameters with bead eometry using learning ability of neural networks. Finally, the developed system, welding gap detecting system and bead shape monitoring system, is expected to the successful capability of automation of welding process by result of simulation.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2000년도 Proceedings of 5th International Joint Symposium on Microeletronics and Packaging
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• pp.17-17
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• 2000

The issue of reflow profiling continues to be a complex topic. The pains often associated with profiling can be reduced greatly if certain guidelines are followed and if there is a strong understanding of the variables that can be encountered during the reflow process. This paper shall discuss the appropriate guidelines and trouble shooting methods for reflow profiling, and in particular shall focus upon the benefits of implementing the linear ramp-to-spike profile. Delta T(T) is defined as the variation of temperature found on an assembly during the reflow process. Too large of a T can result in soldering defects, so to combat T a Ramp-Soak-Spike(RSS) reflow profile often is utilized. However, when using a newer-style reflow oven, the T often is minimized or eliminated, thus, the soak zone of the reflow profile becomes an unnecessary step. Because of this, the implementation of a linear Ramp-To-Spike(RTS) reflow profile should be considered. Benefits such as reduced energy costs, reduced solder defects, increased efficiency, improved wetting, and a simplification of the reflow profile process may be experienced when using the RTS profile. Included in this paper are the suggested process parameters for setting up the RSS and RTS profiles and the chemical and metallurgical reactions that occur at each set point of these profiles. The paper concludes with a discussion and pictures of several profile-related defects. Each of these defects is described, analyzed, and instructions are given for troublshooting these defects.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2002년도 학술대회지
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• pp.432-437
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• 2002

턴키 공사의 실시설계 단계는 기본설계 이후 최종 계약을 위한 준비 단계로써, 수행하여야 할 업무가 많을 뿐만 아니라, 그러한 업무의 결과가 실제 계약서류에 대한 근거가 되므로 턴키 사업 수행자 입장에서는 철저한 관리가 필요한 단계이다. 그러나 국내 건설회사의 경우, 최근까지 단순히 시공 주체로써의 능력만을 키워왔으며 턴키 사업에 대한 경험이 미비하여, 실시설계 단계의 프로세스와 기존사례가 체계화되어 있지 않아 현장관리자가 해당 프로세스에서 업무를 수행하는 데 어려움이 있었다. 이를 해결하기 위해, 먼저 턴키 사업의 이론적 고찰을 통하여 연구의 근거와 필요성을 제시하고, 현장관리자 면담을 통해 실시설계 단계에서 수행하여야 할 업무와 그에 따르는 제반사항에 대해 파악한 후, 실제 발생하였던 의사결정 사항들과 그에 대한 대처방안 및 예방방안에 대해 조사하였다. 그리고 면담조사 결과를 바탕으로 턴키 공사의 실시설계 단계 프로세스 모델과 CBR(Case-Based Reasoning)을 활용한 실시설계관리 방안을 제시하였다.

• 컴퓨터교육학회논문지
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• 제9권1호
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• pp.29-39
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• 2006

본 연구는 학습자의 학습과정과 학습내용, 평가내용을 분석하여 학습내용 중에 이해가 안된 부분이 있거나 문제가 있는 부분을 진단하고 이에 적절한 학습 조언을 제공함으로써 학습의 효과를 높일 수 있도록 하는 적응형 교수 시스템을 제안한다. 학습자의 학습내용 중 한 개념에 대한 학습은 다른 개념의 학습에 영향을 미치며, 한 개념을 학습하기 위해서는 그 개념에 대한 선행개념을 충분히 이해하고 있어야 된다는 점을 고려하여 학습내용을 구성시 컨셉맵을 기반으로 학습개념간의 관련성을 표현하고 있다. 이러한 컨셉맵을 통해 한 개념을 학습하기 전 요구되는 선행개념에 대한 학습 정도를 파악하여 이에 따른 적합한 학습내용을 제공하고, 평가문항과 학습개념과의 관련도를 이용하여 학습자의 학습내용 중 문제 있는 부분을 진단하여 적절한 조언을 제공한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1963-1966
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• 2005

Degenerative lumbar spinal stenosis(DLSS) is a disease inducing low back pain, leg pain, convulsion, numbness, and neurogenic claudication from compression of nerve root. Intervertebra fixation was reported to increase the degenerative of neighbor region after treatment. Recently, a new surgical technique of inserting a fixator between interspinous processes has been introduced. The purpose of this study is to design of the interspinous process fixator with flexibility to complement the trouble of using fixator in DLSS. This study evaluated the existing fixator through the mechanical test and modified fixators using the finite element analysis(FEA). Displacement, stiffness and Von-Mises stress were found to have similar values to those obtained from the mechanical test and the FEA in the biomechanical loading condition. Effects of variation in length and thickness were investigated to design an optimal fixator.

• 한국정밀공학회지
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• 제23권3호
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• pp.195-202
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• 2006

The degenerative lumbar spinal stenosis (DLSS) is a disease inducing low back pain, leg pain, convulsion. numbness, and neurogenic claudication from compression of nerve root. Intervertebra fixation was reported to increase the degeneration of neighbor lesion after treatment. Recently, a new surgical technique of inserting a fixator between interspinous processes has been introduced. The purpose of this study is to design the interspinous process fixator with flexibility to complement the trouble of using fixator in DLSS. This study evaluated the existing fixator through the mechanical test and modified it using the finite element analysis (FEA). The evaluation was based on the displacement, stiffness and von-Mises stress obtained from the mechanical test and calculated from the FEA in the biomechanical loading condition. Effects of variation in length and thickness were investigated to design an optimal fixator. Three prototypes were manufactured using FEA results. Mechanical tests under the biomechanical loading condition were performed to select the best one from these three. The selected fixator increased flexiblity by 32.9%.

• International Journal of Contents
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• 제16권4호
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• pp.50-67
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• 2020

This study investigated whether writing weekly listening logs could influence college English learners' metacognitive awareness and listening proficiency. In addition, the Metacognitive Awareness Listening Questionnaire (MALQ) was applied to examine the learners' knowledge of their listening process. It is process-oriented research conducted by analyzing the MALQ and students' listening logs as to how their metacognitive awareness and listening proficiency have changed during the semester. Eighty-nine students who took an English listening practice course at a university participated in this study. The research findings are as follows. First, it turned out that there was a significant relationship between EFL university students' listening comprehension and some subscales of metacognitive awareness. Second, the students had an opportunity to reflect on learning through regular listening activities, and weekly listening logs, which included important information about listening process and practice. Third, as the students' listening proficiency increased at the end of the semester, it was found that introducing listening logs along with classroom lessons helped the students improve their listening ability. Finally, the high proficiency group students used multiple strategies simultaneously, regardless of the type of listening strategies, while the low proficiency group students used one or two limited listening strategies. However, the low proficiency group students may have had trouble expressing their ideas in English or recognizing the listening strategies they used, not because they did not use a lot of listening strategies. Therefore, teachers should regularly check if students are following their instructions and help them use appropriate strategies for better understanding.

• 산업경영시스템학회지
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• 제39권1호
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• pp.116-122
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• 2016

Recently, the production cycle in manufacturing process has been getting shorter and different types of product have been produced in the same process line. In this case, the control chart using coefficient of variation would be applicable to the process. The theory that random variables are located in the three times distance of the deviation from mean value is applicable to the control chart that monitor the process in the manufacturing line, when the data of process are changed by the type of normal distribution. It is possible to apply to the control chart of coefficient of variation too. ${\bar{x}}$, s estimates that taken in the coefficient of variation have just used all of the data, but the upper control limit, center line and lower control limit have been settled by the effect of abnormal values, so this control chart could be in trouble of detection ability of the assignable value. The purpose of this study was to present the robust control chart than coefficient of variation control chart in the normal process. To perform this research, the location parameter, ${\bar{x_{\alpha}}}$, $s_{\alpha}$ were used. The robust control chart was named Tim-CV control chart. The result of simulation were summarized as follows; First, P values, the probability to get away from control limit, in Trim-CV control chart were larger than CV control chart in the normal process. Second, ARL values, average run length, in Trim-CV control chart were smaller than CV control chart in the normal process. Particularly, the difference of performance of two control charts was so sure when the change of the process was getting to bigger. Therefore, the Trim-CV control chart proposed in this paper would be more efficient tool than CV control chart in small quantity batch production.

• 디지털산업정보학회논문지
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• 제17권4호
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• pp.177-195
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• 2021

The purpose of this study is to examine the trouble of recruitment and research and development of ICT SMEs. Recently, many ICT SMEs have emerged for selling products and services using the technology of the 4th industrial revolution. However, SMEs have relatively deficient resources compared to large companies, the difficulty of maintenance or growth of human resources and intangible resources. This research methodology organized the four stages of the analysis process. The first analysis is the association rules for human resource recruitment. The second analysis is the difficulty of hiring jobs and experienced workers by each stage of company growth. The third analysis is a regression analysis of the trouble of R&D activity. The last analysis is an analysis of association rules on the difficulties of management activities by company growth. As the research result, the first analysis has shown a difference in favored human resources by the ICT industry. The second analysis also showed factor differences in job recruitment difficulties for each stage of corporate growth. In the third analysis, the operation of research institutes in ICT SMEs is influenced by industry type, corporate certification, corporate growth stage, self-technology development, joint technology development, technology transfer, and commercialization. As the last analysis, ICT SMEs showed factor differences in difficulties in management activities by stage of corporate growth. This study contributed empirically emphasizing the troubling phenomenon of human resources and R&D necessary for the growth of ICT SMEs. As a theoretical implication, this research contributed to the research-area expansion of management information using big-data technologies. In particular, this research practically suggests the differentiated direction of recruitment and R&D by ICT SMEs based on industry and each stage of company growth through the association rules of big data.

• Journal of the Korean Wood Science and Technology
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• 제32권4호
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• pp.46-51
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• 2004

본 연구에서는 국산 리기다소나무의 대량 수요 창출과 이용기술 개발, 특히 구조용집성재 라미나로서의 이용 가능성 구명을 위해 고온에서 건조된 판재의 변형량과 변색정도를 조사 평가하였다. 함수율 분포시험을 통해 평가된 고온건조판재 내 적은 함수율 경사, 프롱테스트를 통해 확인된 적은 내부 잔류응력, 집성가공 가능한 적은 변형량 등은 본 연구에서 적용된 고온건조스케쥴이 구조용집성재용 라미나 건조조건으로 사용 가능성이 높다는 결과를 보여주었다. 예비실험을 통해 송진에 의한 접착장애는 발생하지 않는 것으로 확인 되었으나, 잔류수지에 의한 구조용집성재의 접착내구성 및 도장성능 감소현상 구명을 위한 수지정량 분석시험이 추후 요구되었다. 또한 최종 함수율이 집성재 라미나로서 이용 가능한 함수율보다 상당히 낮은 수준으로 건조되었으며 저온열기건조 판재에 비해 변색이 심하므로 함수율 제어 및 변색 억제를 위한 최적의 건조조건 구명에 대한 연구가 좀더 필요할 것으로 사료된다.