• Title, Summary, Keyword: Engineering education

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Investigation of Regraphitization during Cam Shaft Remelting (캠 샤프트 재용융 처리시 재흑연화 현상에 관한 연구)

  • Oh, Young-Kun;Kim, Gwang-Soo;Koh, Jin-Hyun
    • Korean Journal of Materials Research
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    • v.8 no.7
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    • pp.648-652
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    • 1998
  • TIG remelting was performed to harden the surface of automobile earn shaft. Multipass remelting was conducted in longitudinal direction under argon gas atmosphere. The microstructure of as-east earn shaft was gray iron which consisted of flake graphite and pearlitic matrix. The remelted area had microstructue of both fine pearlite and ledeburite structure that consisted of globular austenite and $Fe_3C$. Hardness for as-cast earn shaft had HRc 25~28, however it increased at remelted area to HRc 53~55. Black line was found at heat affected zone next to the fusion line, that is remelt area of previous pass, during multipass remelting. Black line was identified as graphite, which was transformed from $Fe_3C$. in the ledeburite structure. It is observed that all graphites were nucleated at $Fe_3C$. and matrix interface. High density energy laser remelting process was also applied to verify whether black line could be eliminated. However, black line was still existed as observed in TIG remelting process. Regraphitization was simulated on the ledeburitic structure specimen using Gleeble 1500 with conditions of 1100 and 100$0^{\circ}C$ for 0.5, I, 3, 5 and 1Osee. From the fact that graphite was formed even at the simulation condition of 100$0^{\circ}C$ for 0.5sec, it is seen that regraphitization is an inevitable phenomenon generated whatever processes used during multipass overlap remelting.

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Classification of Micro-Landform on the Alluvial Plain Using Landsat TM Image: The Case of the Kum-ho River Basin Area (Landsat TM 영상(映像)을 이용한 충적평가(沖積平野) 미지형(微地形) 분류(分類) -금호강(琴湖江) 유역평야(流域平野)를 대상으로-)

  • Jo, Myung-Hee;Jo, Wha-Ryong
    • Journal of the Korean association of regional geographers
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    • v.2 no.2
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    • pp.197-204
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    • 1996
  • We attempt to classifing method of micro-landform on the alluvial plain, such as natural-levee, backmarsh and alluvial fan, using false color composite of Landsat Thematic Mapper image. The study area is Kumho River Basin on the southeastern part of Korea peninsula. The most effective image for micro-landform classification is the false color composite of band 2, 3 and 4 with blue, green and red filtering. The most favorable time is the middle third of November, because of the density differentiation of green vegetation in most great. In this time the paddy field on the back-marsh is bare by rice harvesting. But on the natural levee the green vegetation, such as vegetables and lower herbs under fruit tree, remain relatively more. On the alluvial fan, the green vegetation condition is medium. For the verification of the micro-landform classification, we employed the field survey and grain size analysis of the deposition of each micro-landform on the sample area. It is clarified that the classification method of micro-landform on the alluvial plain using the Landsat TM image is relatively useful.

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Investigation into a Prototyping Tool for Interactive Product Design: Development, Application and Feasibility Study of MIDAS (Media Interaction Design Authoring System) (인터랙티브 제품 디자인을 위한 프로토타이핑 도구: MIDAS의 활용 사례 및 유용성 연구)

  • Yim, Ji-Dong;Nam, Tek-Jin
    • Archives of design research
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    • v.19 no.5
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    • pp.213-222
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    • 2006
  • This paper presents MIDAS (Media Interaction Design Authoring System), an authoring toolkit for designers and artists to develop working prototypes in new interaction design projects. Field research were conducted to identify the requirements and a case study of designing new interactive products was carried out to examine the feasibility of the new tool. MIDAS provides easier ways of integrating hardware and software, to manage a wide range of electric input and output elements and to employ 3D Augmented Reality technology within conventional multimedia authoring tools, such as Director and Flash, which are popularly used by designers. MIDAS was used in case study projects of design education as well as by voluntary designers for evaluation. From the result of case studies, it was found that many design projects were successfully accomplished using MIDAS. Designers who participated in the projects reported that MIDAS not only helped them to concentrate more on ideation but also was very easy to use as they implemented the physical interface concepts without advanced engineering skills. It is expected that MIDAS can also support prototyping in interactive media an, tangible user interface development and related human computer interaction fields.

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Enhanced Catalytic Activity of Cu/ZnO/Al2O3 Catalyst by Mg Addition for Water Gas Shift Reaction (Mg 첨가에 따른 수성가스전이반응용 Cu/ZnO/Al2O3 촉매의 활성 연구)

  • Park, Ji Hye;Baek, Jeong Hun;Hwang, Ra Hyun;Yi, Kwang Bok
    • Clean Technology
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    • v.23 no.4
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    • pp.429-434
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    • 2017
  • To investigate the effect of magnesium oxide addition, $Cu/ZnO/MgO/Al_2O_3$ (CZMA) catalysts were prepared using co-precipitation method with fixed molar ratio of Cu/Zn/Mg/Al as 45/45/5/5 mol% for low-temperature water gas shift reaction. Synthesized catalysts were characterized by using BET, $N_2O$ chemisorption, XRD, $H_2-TPR$ and $NH_3-TPD$ analysis. The catalytic activity tests were carried out at a GHSV of $28,000h^{-1}$ and a temperature range of $200{\sim}320^{\circ}C$. At the same condition, magnesium oxide added catalyst (CZMA 400) showed that the lowest reduction temperature and stable presence of $Cu^+$, that is active species and abundant weak acid site. Also magnesium oxide added catalysts (CZMA) showed higher catalytic activity at temperature range above $240^{\circ}C$ than the catalyst without magnesium oxide (CZA). Consequently, CZMA 400 catalyst is considered to be excellent catalyst showing CO conversion of 77.59% without deactivation for about 75 hours at $240^{\circ}C$, GHSV $28,000h^{-1}$.

Analysis of Vibration Characteristics for a Molded Dry-type Potential Transformer (몰드형 건식 계기용 변압기 진동 특성 분석)

  • Kim, Moosun;Jang, Dong Uk;Kim, Seung Mo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.3
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    • pp.209-214
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    • 2017
  • Most of the present potential transformers of train vehicles are of the oil-type filled with insulating oil and are susceptible to problems such as explosion due to the increase in the internal pressure during train operation and poor reliability near the end of their life cycle. As a solution to this problem, it is necessary to develop a molded dry-type potential transformer with excellent pressure-resistance performance using insulating resin. In order to localize the product, the Korea Railroad Research Institute has been developing a molded dry-type potential transformer. As part of this research, it is necessary to analyze the vibration characteristics of the developed product and to check the transformer performance in a vibration environment. In this study, a resonance test and simulated long-term life test of the developed product were conducted according to the KS R 9144 and IEC 61373 standards, respectively, which are vibration test methods for railway vehicle parts. Their natural frequencies were analyzed by comparing the results of the numerical modal analysis and resonance test, in order to confirm their adherence to the standards. Also, the performance test after the simulated long-term life test confirmed that the operation of the developed transformer was not problematic even in a long-time vibration environment.

A Study on the Change of the View of Love using Text Mining and Sentiment Analysis (텍스트 마이닝과 감성 분석을 통한 연애관의 변화 연구 : <공항가는 길>과 <이번 주 아내가 바람을 핍니다>를 중심으로)

  • Kim, Kyung-Ae;Ku, Jin-Hee
    • Journal of Digital Convergence
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    • v.15 no.2
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    • pp.285-294
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    • 2017
  • In this study, change of the view of love was analyzed by big data analysis in TV drama of married person's love. Two dramas were selected for analysis with opposite theme of love story. The sympathy of audience for the one month period from the end of the drama was analyzed by text mining and sentiment analysis. In particular, changes in the meaning of home meaning are identified. Home is not 'a place where a husband and wife play a social role', but 'a place where they can share real sympathy and one can be happy'. If individuals are not happy, they need to break their homes. In this study, the current divorce rate and the question regarding the matter should be considered. But based on Google Trends, in Korean society, interest in marriage were still higher than romance. It means that people prefer to 'a love to get marriage' in Korean modern society, than 'love for love affair'. It seems to be reflection of cognition change, marriage should be based on true love. This study is expected to be applied to the study of trend change through social media.

Investigation into Occupational Disease of Merchant Crew (상선승무원들의 질병실태 조사)

  • Kim Jae-Ho;Chang Seong-Rok;Moon Serng-Bae;Ha Hae-Dong;Yang Won-Jae;Lee Sang-Woo
    • Journal of Navigation and Port Research
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    • v.30 no.6
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    • pp.551-559
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    • 2006
  • The purpose of this study was to find out morbidity rate and pattern of disease and affect of variables related disease and medical management of seafares'. The subjects this study were 1049 seafares' were took education in Korea Institute of Maritime and Fisheries Technology. This questionnaire was focused on finding the basic data for prevention of disease and promotion health for the seafares'. The collected data were analyzed by using descriptive statistics, Chi-square, cross tab, linear regression by SPSS 10.1 package. The result of this study are as follow. 1)The morbidity rate within recent 12 months was 69.0%. 2)there were significant differences qf occurred disease in age(p<0.05), income(p<0.01), career of ship on board(p<0.01), rank(p<.01), perceived health status(p<0.01), worry of health(p<0.01), fatigue symptoms(0.01), satisfy of job(p<0.05), rest time(p<0.05) 3) Considering disease unable to work more than 4 hour, the number of those who had oral disease 7.3%> tinea 6.6%> gastric ulcer 6.4, and musculoskeletal disease group were 20.9%, which revealed the highest rate oral disease 13.6%> skin disease> 12.4%, digestive disease> 12.1%. 4) As refer to medical management, The pain above 31days 35.7%, hospitalization and treatment below 7days were each 50.2%, 42.8%, medical service were doctor's office 27.9, which revealed the highest rate.

A Study on the Disaster Prevention Technology of the Switchboard with Upper and Lower Bending Type Seismic Pads (상하굴절형 내진패드를 설치한 수배전반 방재기술에 관한 연구)

  • Lee, Taeshik;Seok, Gumcheul;Lee, Jaewon;Kim, Taejin;Kim, Jaekwon;Cho, Woncheol
    • Journal of Korean Society of Disaster and Security
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    • v.10 no.1
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    • pp.85-90
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    • 2017
  • The purpose of this study is to investigate the effect of vertical and horizontal refraction on the lower part of the power supply and control system of various facilities and machinery that use electricity, so that the power distribution system, which is an important electric facility installed in buildings and public facilities, Type earthquake resistant pads to protect the substructure and prevent short-circuiting on the upper part of the system. The GR-63-CORE (Scale 8.3 class) It is earthquake disaster prevention and disaster prevention technology that satisfies seismic performance. As a research result, it is possible to protect the electricity and communication infrastructure, which can contribute to shortening the time for recovering the electric facilities to the normal state in case of an earthquake, and preventing the fire caused by the destruction of the electricity supply facility in case of an earthquake. As a result, it is possible to minimize the spread of fire that occurs when a large-scale earthquake occurs and to minimize the damage of people and damage to property, and it can contribute to the securing of electric infrastructure that enables citizens to quickly recover to daily life even after suffering a major earthquake. In addition, the technology can be applied to ensure the seismic resistance of the equipment in the communication and computer room, and it can be applied to various fields where the facility function can be stopped due to the shaking of the earthquake base.

On-Land Seismic Survey of Korea (한국의 육상 탄성파탐사)

  • Kwon, Byung-Doo
    • Economic and Environmental Geology
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    • v.39 no.4
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    • pp.441-450
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    • 2006
  • The on-land seismic survey in Korea was begun in mid-1960s. Kim et al.(1967) of Korea Geological Survey reported on the result of gravity and seismic reflection surveys conducted in the Pohang area for the period of 1963-64 to assess its possibility of oil entrapment. Hyun and Kim (1966) carried out a refraction survey on the tunnel wall. Since then, the KGS geophysicists had conducted seismic surveys on Kyungsang sedimentary basin as a main project for several years. In 1970s, on-land seismic surveys had been conducted for various purposes such as site investigation for the nuclear power plants and industrial complex, exploration for ground water, mineral resources and underground tunnel. The first reflection survey with CMP acquisition was attempted in 1978 by using a digital recording system. But most of on-land seismic surveys had employed the refraction method until 1980s. In 1990s, high resolution reflection and various borehole seismic surveys such as tomography, uphole, downhole, cross-hole methods have been attempted by universities and engineering companies. The applications of on-land seismic surveys have been enlarged for both academic and industrial purposes such as investigation of geologic structure of the fault and tidal flat area, construction of highway, railroad and dam, geothermal energy and mineral resource exploration, environmental assessment for waste disposal sites and archaeological investigations. In 2002, the first crustal seismic survey was carried out on the profile of 294km length across the whole peninsular. It is expected that the advanced technology and experience acquired through offshore seismic surveys, which have been conducted in continental shelf of Korea and foreign oil fields, will stimulate the more active on-land seismic explorations.

Effect of Systems Thinking Based STEAM Education Program on Climate Change Topics (시스템 사고에 기반한 STEAM 교육 프로그램이 기후변화 학습에 미치는 효과)

  • Cho, Kyu-Dohng;Kim, Hyoungbum
    • The Journal of the Korea Contents Association
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    • v.17 no.7
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    • pp.113-123
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    • 2017
  • This research is designed to review the systems thinking and STEAM theory while ascertaining the effects of the classroom application of the STEAM programs based on systems thinking appropriate for studying climate change. The systems thinking based STEAM program has been developed by researchers and experts, who had participated in expert meetings in a continued manner. The program was applied to science classes over the course of eight weeks. Therefore, the application effects of the systems thinking based STEAM program were analyzed in students' systems thinking, STEAM semantics survey, and students' academic achievement. The findings are as follows. First, the test group has shown a statistically meaningful difference in the systems thinking analysis compared to the control group in the four subcategories of 'Systems Analysis', 'Personal Mastery', 'Shared Vision' and 'Team Learning' except for 'Mental Model'. Second, in the pre- and post-knowledge tests, the independent sample t-test results in the areas of science, technology, engineering, art and mathematics show statistically meaningful differences compared to the control group. Third, in the academic performance test regarding climate change, the test group displayed higher achievement than the control group. In conclusion, the system-based STEAM program is considered appropriate to enhance amalgamative thinking skills based on systems thinking. In addition, the program is expected to improve creative thinking and problem-solving abilities by offering new ideas based on climate change science.