• Title/Summary/Keyword: assembly works

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Contemplation of the Campus Planning (캠퍼스 개발계획에 대한 고찰)

  • Lee, Ja-Won
    • Journal of the Economic Geographical Society of Korea
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    • v.11 no.1
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    • pp.148-163
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    • 2008
  • As with cities, all components of a campus must be carefully calibrated to provide the facilities, services like energy, water, electricity, information and communication; classrooms, libraries and laboratories for working; transportation networks and systems for movement of persons, goods, and services; athletic and other facilities for health and competition; places to eat, recreate and socialize; places to display and store works of arts; spaces for the performing arts' spaces for active assembly or solitary pondering. The goal of this study is how to observe the campus planning and development as a part in the context of the community. This study was taken into account neighborhood concerns and Harvard design guidelines. As an observer for the university's northern campus edge, this study suggests in the context of a long and sometimes turbulent history of dialogue and negotiations between Harvard University and first host community, Agassiz which is one of Cambridge's thirteen neighborhoods.

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A Study on the Coloring and the Arrangement of Colors of Korean Traditional Embroidery (한국 전통 자수의 색채와 배색에 관한 연구)

  • Yun, Ji-Young;Ha, Ji-Soo
    • Journal of the Korean Society of Costume
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    • v.56 no.8 s.108
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    • pp.95-112
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    • 2006
  • This study examines the Korean traditional and characteristic coloring through the color of Korean traditional embroidery. This research gives the chance to establish the cultural identity of Korea and presents the aesthetic standard of color images. Also, practical use of Korean traditional colors through this study provide opportunities which develope cultural merchandise in the world. were chosen as the references to analyzed the Korean traditional colors through gungsu: court embroidery, buddhist embroidery, everyday embroidery and clothing embroidery. Because this book published in commemoration of '20th General Conference and 21th General Assembly of ICOM' in 2004, which presented excellence of Asian culture. The color of these works were divided by 'Pantone Solid Color Chips' which organized by CMYK color system and categorized by Obangsaek. 'Gungsu' had vivid and splendid color sense which used strong and bright colors and 'buddhist embroidery' had mild and mysterious feelings which used low saturation.'Everyday embroidery' used the red color group frequently and 'clothing embroidery' had brighter colors comparing to other embroidery groups. The 'Chung(blue)' group had diverse color tone rather than one-tone color. This means that Koreans prefer the 'Chung' and used it regularly, also this color symbolized the racial characteristics. Even though 'Whang(yellow)' was prohibited because the color for emperor, in the case of embroidery, there were a variety of yellow colors from 'gold' to pale yellow and grayish yellow. The arrangement of colors in 'gungsu', tone on tone, complementary and bicolore coloring was used mostly which presented a strong and elegant color sense. On the other side, 'buddhist embroidery' used tonal coloring which gave gentle and noble feeling. 'Everyday embroidery' presented separation and accented coloring which was the example of common people's humor and originality. In the case of 'clothing embroidery', there was dominant lightness, separation, tone on tone and camaieu coloring which added gorgeousness in Korean traditional clothing.

A Study on the Development and Surface Roughness of Roller Cam SCM415 by 5-Axis Machining (5축 가공에 의한 SCM415 롤러 캠 개발과 표면조도 연구)

  • Kim, Jin Su;Lee, Dong Seop;Kang, Seong Ki
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.4
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    • pp.397-402
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    • 2013
  • In this study, we carried out the each lines of section, using GC (green silicon carbide) whetstone, the SCM415 material which separated by after and before heat treatments process, in 3+2 axis machining centers for integrated grinding after cutting end mill works, the spindle speed 8000 rpm and feed rate 150 mm/min. For the analysis of the centerline average roughness (Ra), we measured by 10 steps stages. Using Finite element analysis, we found the result of the load analysis effect of the assembly parts, when applied the 11 kg's load on both side of the ATC (Automatic tool change) arm. The result is as follows. For the centerline average roughness (Ra) in the non-heat treatment work pieces, are appeared the most favorable in the tenth section are $0.510{\mu}m$, that were shown in the near the straight line section which is the smallest deformation of curve. In addition, the bad surface roughness appears on the path is to long by changing angle, the more inclined depth of cut, because the chip discharging is not smoothly.

Research on the actual vibration exposure of workers engaging in vibration induced works (진동작업 종사 근로자의 진동노출 실태에 관한 연구)

  • Kim, Kab-Bae;Chung, Eun-Kyo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.04a
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    • pp.178-185
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    • 2012
  • In Korea, researches on the exposure assessment of the hand-transmitted vibration started from the mid-90, however, they were performed in the limited industries such as auto-assembly plants and the evaluation of the vibration was mostly conducted by ISO 5349(1986). Therefore, it was necessary to assess hand-transmitted vibration levels of workplace such as ship building/repairing industry or mining industry where occupational injuries are largely occurred and to evaluate the vibration levels using revised ISO 5349(2001). The SVAN 949 Four Channels Sound & Vibration Analyser was used for the measurement. The workers using a chain saw were exposed to $1.7{\sim}2.8m/s^2$ of daily vibration level. Workers using a rock drill in a coal mining were exposed to the highest vibration acceleration among workers and the levels were $7.1{\sim}10.8m/s^2$. Vibration levels of grinders were different according to the types of grinders. The hand-transmitted vibration of 3 types of grinders were measured and the levels were $3.3{\sim}11.1m/s^2$. Workers using a impact wrench were exposed to $1.5{\sim}1.6m/s^2$ of vibration. Out of 20 kinds of machines, only 4 tools provided the information of vibration acceleration on the instructions. In addition, the current condition of workplaces to control vibration was not much different from the past because there are no vibration exposure limit.

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Development and Implementation of a Skill Transfer System for a Self-Tapping Screw-Tightening Operation

  • Matsumoto, Toshiyuki;Doyo, Daisuke;Shida, Keisuke;Kanazawa, Takashi
    • Industrial Engineering and Management Systems
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    • v.10 no.3
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    • pp.209-220
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    • 2011
  • Self-tapping screws have some operational peculiarities. In spite of their economical advantage that requires no prior tapping operation, a weakness of self-tapping screw-tightening operations is that screws can easily be tightened at a non-right angle, thus resulting in an improper tightening strength. Increases in outsourced workers have reduced labor costs, but the accompanying high worker fluidity means that new workers are more frequently introduced into factories. It is necessary to train new workers for self-tapping screw-tightening operations, which occupies a considerable portion of ordinary assembly works. The purpose of this study is to develop and implement a skill transfer system for the operation. This study (1) proposes a set of characteristic values for evaluating the quality of the operation and develops a device that can measure these values; (2) proposes criteria for evaluating the resultant quality of the tightening; and (3) develops a skill training system for better work performance. Firstly, sets of characteristic values for evaluating the quality of the operation, namely, torque, vertical pressure forces and horizontal vibration forces, are proposed. A device that can measure these values is developed. Secondly, criteria for evaluating the resultant quality of the tightening are identified, involving tightening torque, maximum vertical pressure and timing, vibration area during the processing and tightening period, and work angle. By using such parameters, workers with the proper aptitude can be identified. Thirdly, a skill training system for the operation is developed. It consists of screwdriver operation training and screw-tightening training with feedback information about the results of the operation. Finally, the validity of the training system is experimentally verified using new operators and actual workers.

Study on the Mechanical Face Seal Performance for a 7-ton-Class Turbopump (7톤급 터보펌프 기계평면실의 성능 시험 연구)

  • Bae, Joonhwan;Kwak, Hyun D.;Choi, Changho
    • Tribology and Lubricants
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    • v.32 no.5
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    • pp.154-159
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    • 2016
  • This paper presents an experimental study of the leakage performance and endurance performance of a mechanical face seal in the 7-ton-class turbopump of the Korea Space Launch Vehicle 2 third-stage engine. We install a mechanical face seal between the fuel pump and turbine to prevent the mixing of the fuel and turbine gas. We design and manufacture a prototype mechanical face seal, which has two parts, namely, a bellows seal assembly and mating ring. We set up a test facility to measure the leakage and endurance of the mechanical face seal. For the similarity tests, we use water under real operating conditions such as high rotational speed, high temperature, and high pressure. Through investigation of the leakage and carbon wear rate, it is possible to evaluate the performance of the mechanical face seal. The results of the leakage and endurance performance test demonstrate the absence of any leakage from the prototype mechanical face seal after a trial run and clarify that the acceptable wear rate fully satisfies the turbopump requirements. Finally, we install a qualified mechanical face seal in a 7-ton-class turbopump and perform a validation test in the turbopump real-propellant test facility in the Korea Aerospace Research Institute. The test results confirm that the mechanical face seal works well under real operating conditions.

Research Trends of Scheduling Techniques for Domestic Major Industries (국내 주요 산업별 스케줄링 기법의 연구동향)

  • Lee, Jae-yong;Shin, Moonsoo
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.41 no.1
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    • pp.59-69
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    • 2018
  • The up-to-date business environment for Korean manufacturers is very complex and rapidly changing. Especially, the companies have faced with various changes derived from small quantity batch production, diversification of customer demands, and short life cycles of products. Consequently, the Korean manufacturing companies are in need of more efficient production planning and scheduling techniques. In this paper, the research trend of scheduling techniques is investigated to provide relevant information to researchers in this field. Furthermore, some implications for future researches are presented regarding literatures published in Korea over the last 10 years. This paper presents an entire investigation into Korean research works on scheduling (2,569 papers) that are published from 2007 to 2016. Especially, detailed analysis was carried out in the following three industry : 1) semiconductor, 2) shipbuilding and 3) automobile. In this paper, approaches to scheduling presented in the literature are categorized into the following three categories : 1) application, 2) algorithm, and 3) simulation modeling. First, in the semiconductor industry, scheduling techniques related to semiconductor cleaning processes, photolithography processes, chemical processes, transport and transport equipment have been found to be dominant. Second, the shipbuilding industry is focused on assembly processes, transporter, crane and various existing production management system. On the other hand, the scheduling research of the automobile industry is mainly focused on the vehicle movement routing and procurement supply-chain planning algorithm in terms of logistics. The conclusion of this study are expected to provide many implications for various types of academic and practical follow-up studies related to scheduling in consideration of main characteristics of semiconductor, shipbuilding and automobile industries.

Design Considerations on Large-scale Parallel Finite Element Code in Shared Memory Architecture with Multi-Core CPU (멀티코어 CPU를 갖는 공유 메모리 구조의 대규모 병렬 유한요소 코드에 대한 설계 고려 사항)

  • Cho, Jeong-Rae;Cho, Keunhee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.2
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    • pp.127-135
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    • 2017
  • The computing environment has changed rapidly to enable large-scale finite element models to be analyzed at the PC or workstation level, such as multi-core CPU, optimal math kernel library implementing BLAS and LAPACK, and popularization of direct sparse solvers. In this paper, the design considerations on a parallel finite element code for shared memory based multi-core CPU system are proposed; (1) the use of optimized numerical libraries, (2) the use of latest direct sparse solvers, (3) parallelism using OpenMP for computing element stiffness matrices, and (4) assembly techniques using triplets, which is a type of sparse matrix storage. In addition, the parallelization effect is examined on the time-consuming works through a large scale finite element model.

The Construction Status of Fuel Test Loop Facility (핵연료 노내조사시험설비의 시공 현황)

  • Park, Kook-Nam;Lee, Chung-Young;Kim, Hark-Rho;Yoo, Hyun-Jae;Yoo, Seong-Yeon
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.305-309
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    • 2007
  • FTL(Fuel Test Loop) is a facility that confirms performance of nuclear fuel at a similar irradiation condition with that of nuclear power plant. FTL construction work began on August, 2006 and ended on March, 2007. During Construction, ensuring the worker's safety was the top priority and installation of the FTL without hampering the integrity of the HANARO was the next one. The installation works were done successfully overcoming the difficulties such as on the limited space, on the radiation hazard inside the reactor pool, and finally on the shortening of the shut down period of the HANARO. The Commissioning of the FTL is to check the function and the performance of the equipment and the overall system as well. The FTL shall start operation with high burn up test fuels in early 2008 if the commissioning and licensing progress on schedule.

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Integrate Processing Scheme of Flow Control Language (흐름 제어 언어의 통합 처리)

  • Kim, Tae-Wan;Chang, Chun-Hyon
    • The KIPS Transactions:PartD
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    • v.11D no.2
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    • pp.415-422
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    • 2004
  • Automation systems improve the productivity of works which relate to product design, facilities management, fault processing and quality evaluation. In these systems, the description language for monitoring and control process is called new control language. These are five flow control languages : IL, ST, FBD, SFC and LD. IL and ST are based on left form. FBD, SFC and LD are based on graphic form. Generally, a software which monitors and controls a system is allowed to use just one flow control language. It is impossible to use more than two languages for simulation in the same system environment. In this paper, we analyzed the characteristics of flow control languages and the process of programming in the legacy system. In addition, for the Integrated processing of languages, we propose Extended ST based on the high-level ST language. Based on this research, we implement a graphical language editor and EST-IL convertor. The graphical language editor makes sequence rules, and converts graphical language into EST. EST-IL convertor has a function to convert EST into IL which is similar to assembly language. As the result of this paper, we present a scheme which integrates all the flow control language processing based on IL.