• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.673-682
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• 2017

As the culture of making things based on "do-it-yourself" (DIY) activity is increasingly promoted, the use of recent digital technologies and tools, including the 3D printer, have become widespread. However, the use of computerized numerical control (CNC) engraving machine is considered difficult because of the complicated procedures and specialized knowledge required for its operation. Therefore, this study aims to resolve the issue that limits the usability of the CNC engraving machine. This paper presents a novel CNC engraving machine system for non-experts based on human-centered design. First, the size and type of the workpiece and tool are reduced. Second, computer-aided process planning (CAPP) steps such as tool path generation, workpiece clamping, and corresponding coordinate system are automated by compromising productivity and efficiency. As a result, a CNC engraving machine system that can be easily used by non-experts was developed. This development has great significance in that it opens up the possibility of using the CNC engraving machine for a wider range of DIY activities.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.705-708
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• 2020

공공시설에 대한 안전점검은 공공시설의 노후화에 따라 정기적인 검사의 필요성이 요구되고 있다. 기존의 안전점검 방식은 대부분 육안으로 점검하는 것에 의존하는데 이는 점검자의 숙련도에 따라 결과의 품질이 달라지게 된다. 본 논문에서는 XAI 기반의 공공시설물 건전도 안전검사 평가시스템을 제안하며, 이는 점검자의 숙련도와 무관하게 항상 같은 결과를 도출해 내며 XAI 를 통해 사용자에게 안전점검에 대한 결과를 제시해준다. 공공시설물 중 터널 시설물의 안전검사 평가시스템을 기반으로 하는 연구를 진행하였으며 이는 수정없이 교량 시설물 등 다른 공공시설물에 적용이 가능하다. 본 논문은 5 가지로 구분된다. 1) 터널 이미지와 균열에 마스크를 적용한 이미지 두 가지의 데이터 셋을 448x448 로 생성한다. 2) UNet 과 Resnet152 의 두 모델을 적용한 혼합 모델을 이용하여 생성한 데이터 셋을 훈련시킨다. 3) 훈련된 혼합 모델에서 생성된 분할 이미지에 대해 노이즈 제거 과정을 진행한다. 4) 노이즈 제거가 끝난 이미지에 스켈레톤화(Skeletonization)를 적용시켜 균열 이미지의 뼈대를 구한다. 뼈대 이미지 기반으로 균열의 길이, 두께, 위치등의 정보를 얻는다. 5) XAI 부분에서는 뼈대 이미지의 정보를 토대로 균열의 위치, 두께, 길이 등에 대해 계산을 진행한 후 사용자에게 제시해준다.

• KDI Journal of Economic Policy
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• v.28 no.1
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• pp.95-116
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• 2006

Traditionally, foreign labor inflow into Korea has been rare and, hence, issues on foreign workers did not draw much attention. However, changing economic conditions of the Korean economy, such as "labor-shortage" problem in SMEs in manufacturing sector, has made the Korean government open its door to the foreign workers since the early 1990s through the Industrial Trainee System. The inflow of foreign workers, on the other hand, has generated various social and economic problems, such as substantial increase of illegal over-stayers, illegal utilization of foreign unskilled workers by domestic SMEs, to name a few. Against this background, the Employment Permit System was implemented from 2004. This new system aims at supplying foreign workers to SMEs as well as protecting them as legal 'employees'. In any case, it is very important to understand how and to what extent the inflow of foreign workers have affected the Korean economy in order to establish long-term policy stance. This paper aims to empirically assess the economic impact of foreign workers on domestic workers in the manufacturing sector during 1997~20001, focusing on the Industrial Trainee System. The empirical results of the paper can be summarized as follows. First, there is some evidence that male semi-skilled workers are the group that is likely to have been displaced by industrial trainees. Second, we were unable to find any strong evidence suggesting that the inflow of foreign industrial trainees decreased wages of less-skilled Korean workers.

• Journal of the Korean Society for Nondestructive Testing
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• v.13 no.1
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• pp.29-39
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• 1993

초음파탐상검사는 그 검사결과가 여타 비파괴검사법에 비해 검사자, 검사장비, 절차서 등 검사 시스템에의 의존도가 높으며, 이중에서도 특히 검사자의 능력과 숙련도에 크게 좌우된다. 따라서 검사결과의 신뢰도를 높이기 위해서는 무엇보다도 검사자에 대해 엄격한 자격인정(Qualification)이 필요하다. 초음파탐상검사는 원자력 발전소 기기의 가동전중검사시 가장 많이 적용하는 체적검사법으로써, 결함검출 및 평가의 신뢰도를 확보하기 위하여 최근 관련 기술기준에서는 검사자에 대해 보다 엄격한 자격인정을 요구함과 아울러 초음파탐상검사 시스템(검사자, 장비, 절차서)에 대한 기량검증(Performance Demonstration)까지를 요구하고 있다. 위의 두 가지 요건을 성공적으로 충족시킬 수 있다면, 초음파탐상기술의 신뢰도는 크게 향상될 것이다. 본고에서는 최근 보다 강화된 원전 가동전중검사 초음파탐상검사 요원의 자격인정요건에 대해 자세히 알아봄으로써 관련 국내 기술기준의 제정과 앞으로 국내 원전 초음파탐상 검사요원에 대한 본 자격인정요건의 적용에 대비코자 하였다. 한편, "초음파탐상검사 시스템에 대한 기량검증 요건"은 초음파탐상 검사요원의 자격인정 요건과 밀접한 관계가 있으므로 다음에 별도로 기술코자 한다.

• The Korean Journal of Nuclear Medicine
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• v.35 no.3
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• pp.142-151
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• 2001

Purpose: This study was performed to search the relatively specific brain regions related to the semantic processing of Korean and English words on the one hand and the regions common to both on the other. Materials and Methods: Regional cerebral blood flow associated with different semantic tasks was examined using $[^{15}O]H_2O$ positron omission tomography in 13 healthy volunteers. The tasks consisted of semantic tasks for Korean words, semantic tasks for English words and control tasks using simple pictures. The regions specific and common to each language were identified by the relevant subtraction analysis using statistical parametric mapping. Results: Common to the semantic processing of both words, the activation site was observed in the fusiform gyrus, particularly the left side. In addition, activation of the left inferior temporal gyrus was found only in the semantic processing of English words. The regions specific to Korean words were observed in multiple areas, including the right primary auditory cortex; whereas the regions specific to English words were limited to the right posterior visual area. Conclusion: Internal phonological process is engaged in performing the visual semantic task for Korean words of the high proficiency, whereas visual scanning plays an important role in performing the task for English words of the low proficiency.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.5
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• pp.163-173
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• 2020

In this study, on-site corporate instructors participated as student-cum-workers in a degree-linked high skills Meister course to improve job competency and practical ability as proposed in the Work-Study Career Vision. Evaluation questions were then developed and their validity was verified by assessing satisfaction related to expected goals in enhancing advanced training guidance and competency as an evaluator. Satisfaction assessment was conducted based on training preparation, training implementation, training effectiveness and training administration. The Delphi Method was adopted and a total of 48 items were developed in 6 categories under 4 main areas. There were 7 evaluation items on the satisfaction of training course development under training preparation, 21 evaluation items related to the satisfaction of Off-JT and OJT courses under training implementation, 16 evaluation items related to the satisfaction of increased competency as an on-site corporate instructor and the satisfaction of enhanced practical skills and skills application at work under training effectiveness, as well as 6 evaluation items to assess satisfaction with administrative support under training administration. The final conformity assessment was conducted based on the stability, content validity ratio, consensus and convergence indicators of the developed items. Results of this study do not only apply to quality management of the high skills Meister course which is being promoted as a pilot project for work-study programs, but also serves as a rationale that may be considered as a basic research tool in the collection of various opinions to derive overall system improvement factors for the work-study high skills Meister course.

• Journal of the Korean Regional Science Association
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• v.31 no.2
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• pp.79-100
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• 2015

In spite of the various government policies to increase the jobs and to improve the employment environment, the unemployment rate has not reduced. The aims of this study are to analyze the structural mismatch(especially geographical mismatch) between job opening and job seeking, and thus to comprehend more deeply the factors affecting unemployment rates of economic regions in Korea. For the period of 2008~2013, the unemployment rates caused by geographical mismatches between job opening and job seeking have been increased steadily. For Chungcheong, Dongnam and Honam economic region, geographical mismatches of low-educated and low-skilled jobs showed relatively quite high, indicating that the job seeker have a strong tendency of preferring certain areas in looking for their jobs. It means that the job seeker can get a job only to move the other areas within an economic region. However, for Capital region, which is the largest job seekers in Korea, geographical mismatches in all types of jobs showed very quite low. So, it is very difficult for the job seeker to escape from unemployment when changing the other areas in looking for a job in Capital region. The results of this study gives an important implication that a nationwide uniform unemployment policy may not be effective to reduce unemployment conditions, and a differentiated unemployment policy should be established in considering the characteristics of geographic mismatches by the types of job in terms of the level of education and skill for each economic region.

• Korean Journal of Applied Biomechanics
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• v.18 no.3
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• pp.33-42
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• 2008

The purpose of this study was to analyze kinematic variables during Side kick motion in Taekwon Aerobics. The subjects of this study were the 7 skilled and 7 unskilled female college students. A QTM and an Auto Track were used to acquire raw data. The sampling rates camera was 100 Hz. The parameters were calculated and analyzed with Visual3D and SPSS 12.0. The results were as following; 1. In the elapsed time, there was no significance difference statically between a skilled and unskilled group. 2. In the cases of knee angle, there was significant difference statically at Maximum Knee Flexion2(p=0.046, F=4.925). 3. In the cases of knee angular velocity, there was significant difference statically at Maximum Knee Flexion1(p=0.031, F=5.940). 4. In the flexion/extension of hip angle, there was significant difference statically at Maximum Knee Flexion2(p=0.012, F=8.668). 5. In the abduction/adduction of hip angular velocity, there was significant difference statically at Minimum Knee Flexion (p=0.019, F=7.324). 6. In the external rotation/internal rotation of hip angular velocity, there was significant difference statically Minimum Knee Flexion(p=0.005, F=11.87).

• Journal of Convergence for Information Technology
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• v.9 no.8
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• pp.140-147
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• 2019

The purpose of this study is to find biomechanical parameters for optimal shoes production through an ergonomic usability assessment of five existing types of shoes preferred by B-BOY. Ten experts and ten non-experts participated in the experiment, and 12 infrared cameras (Qualis, Oqus), force plate (Kistler, 9286AA) and foot pressure plate (Zebris Gmbh, Zebris PDM-System) were used to obtain the data. The results of the study are as follows. First, P shoes with a friction coefficient of 0.38 and a free moment of 0.32 N/m/kg are desirable in terms of traction capability and safety. Second, on the cushion, it was found that the N shoes 2.51 N, sec/kg and non-expert, and 2.86 N and sec/kg were suitable. Third, it is deemed appropriate for C shoes with a forefoot average pressure of 10.11 KPa (right), 10.05 KPa (left), and V shoes with a rearfoot average pressure of 8.4 KPa (right) and 8.36 KPa (left). In conclusion, the combination of the structure and material of V shoes should be developed for traction and stability, N shoes for cushion, and walking balance for C and V shoes.

• Tunnel and Underground Space
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• v.31 no.1
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• pp.10-24
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• 2021

Rock mass classification for construction of underground facilities is essential to secure their stabilities. Therefore, the reliable values for rock mass classification from the precise information on rock discontinuities are most important factors, because rock mass discontinuities can affect exclusively on the physical and mechanical properties of rock mass. The conventional classification operation for rock mass has been usually performed by hand mapping. However, there have been many issues for its precision and reliability; for instance, in large-scale survey area for regional geological survey, or rock mass classification operation by non-professional engineers. For these reasons, automated rock mass classification using LiDAR becomes popular for obtaining the quick and precise information. But there are several suggested algorithms for analyzing the rock mass discontinuities from point cloud data by LiDAR scanning, and it is known that the different algorithm gives usually different solution. Also, it is not simple to obtain the exact same value to hand mapping. In this paper, several discontinuity extract algorithms have been explained, and their processes for extracting rock mass discontinuities have been simulated for real rock bench. The application process for several algorithms is anticipated to be a good reference for future researches on extracting rock mass discontinuities from digital point cloud data by laser scanner, such as LiDAR.