• 시스템엔지니어링학술지
• /
• 제12권1호
• /
• pp.7-23
• /
• 2016

Plant engineering industry is considered as a key industry which will drive the future of Korea. However, Korean plant engineering companies have recently made huge losses in overseas businesses and the lack of engineering capability is pointed out as a main cause of this situation. Unlike Korean plant engineering companies, world leading engineering companies such as Flour and Bechtel have their own systems Engineering Standards/Guides ensuring successful fulfillments of the concept and basic design processes. An engineering standard for an organization is an essential means to shorten the time for engineering design, to maintain the engineering quality and to secure the engineering efficiency in the development of the complex system. Korean plant engineering companies'lack of engineering capability comes from the absence of the engineering standard. In the paper, we have developed a steel-making plant engineering standard based on a systems engineering standard. We chose both ISO/IEC/IEEE 15288 and NASA SE Handbook as main reference standards. First, we have introduced a life-cycle definition and a physical hierarchy of a general steel-making plant. Then we have introduced detailed engineering processes of each life-cycle stage. The full scope of the study was from the feasibility study to the basic design but in the paper, we have only introduced detailed engineering processes and exit criteria for the feasibility study and the concept design.

• 시스템엔지니어링학술지
• /
• 제11권1호
• /
• pp.81-93
• /
• 2015

Steam Reforming H2 Generation (SRH2G) System is a chemical process to produce hydrogen through steam reforming of hydrocarbon. Largely speaking, there are two types of materials for the SRH2G: 1) Oil and coal, and 2)Natural Gas such as shale gas. From the perspective of cost, quality (purity), and environmental burden (pollution), the latter is much more desirable than the former. For this reason, research on SRH2G using natural gas is actively carried out, and implemented and operated in the various industry. In this paper, we develop a natural gas based SRH2G system via systems engineering approach. Specifically, we first derived stakeholder requirements, followed by systems requirements and finally system architecture via a tailored SE process for plant (called Plant Systems Engineering (PSE) process) based on ISO/IEC 15288. The developed method was applied to iron and steel plant as a case study. Through the case study, by the SE approach, we were convinced that a successful system satisfying stakeholders' requirements within the given constraints can be developed, verified and validated.

• 대기
• /
• 제30권4호
• /
• pp.377-390
• /
• 2020

Not only emissions, but also atmospheric circulation is a key factor that affects local particulate matters (PM) concentrations in Korea through ventilation effects and transboundary transports. As part of the atmospheric circulation, air stagnation especially adversely affects local air quality due to weak ventilation. This study investigates the large-scale circulation related to air stagnation over Korea during winter and projects the climate change impacts on atmospheric patterns, using observed PM data, reanalysis and regional climate projections from HadGEM3-RA with Modified Korea Particulate matter Index. Results show that the stagnation affects the PM concentration, accompanied by pressure ridge at upper troposphere and weaken zonal pressure gradient at lower troposphere. Downscaling using HadGEM3-RA is found to yield Added-Value in the simulated low tropospheric winds. For projection of future stagnation, SSP5-8.5 and SSP1-2.6 (high and low emission) scenarios are used here. It has been found that the stagnation condition occurs more frequently by 11% under SSP5-8.5 and by 5% under SSP1-2.6 than in present-day climate and is most affected by changes in surface wind speed. The increase in the stagnation conditions is related to anticyclonic circulation anomaly at upper troposphere and weaken meridional pressure gradient at lower troposphere. Considering that the present East Asian winter monsoon is mainly affected by change in zonal pressure gradient, it is worth paying attention to this change in the meridional gradient. Our results suggest that future warming condition increase the frequency of air stagnation over Korea during winter with response of atmospheric circulation and its nonlinearity.

• Environmental Engineering Research
• /
• 제21권1호
• /
• pp.84-90
• /
• 2016

Regionally the lowest average concentration of TOC was observed with 0.66 mg/L in Nakdong river, while the highest concentration of TOC was observed with 0.91 mg/L in Yeongsan river. The average concentration of TOC for national water quality monitoring site showed that the lowest average concentration of TOC was 1.58 mg/L in Han river, while the highest concentration of TOC was 3.37 mg/L in Yeongsan river. Seasonally, the average concentration of TOC at six upstream sites showed 0.77 mg/L and 0.56 mg/L, 0.69 mg/L and 0.63 mg/L, 0.80 mg/L and 0.73 mg/L, and 1.21 mg/L and 0.68 mg/L between wet season and dry season in Han river, Nakdong river, Gem river and Yeongsan river, respectively. For the national water quality site, the average concentration of TOC between wet season and dry season was 1.70 mg/L and 1.45 mg/L in Han river, 2.01 mg/L and 1.75 mg/L in Nakdong river, 2.01 mg/L and 1.60 mg/L in Gem river, and 3.75 mg/L and 3.00 mg/L in Yeongsan river. The distribution of TOC in upstream and national water quality monitoring sites on four major rivers have been influenced by seasonal and regional characteristics in Korea.

• 시스템엔지니어링학술지
• /
• 제10권2호
• /
• pp.21-31
• /
• 2014

Recently, global market competition of iron and steel products is ever increasing due to over-supply from increased number of industries in rapidly growing countries, such as China, Brazil, and Indonesia. To occupy the big market, major industries are trying to develop high quality, high performance steel products via developing a new iron and steel making process. In other words, development of a new and innovative steel plant is a key to cope with the tough situation. Design and development for the life cycle of iron and steel making plant is very much complex and multi-disciplinary. In this paper, Plant Systems Engineering (PSE), a tailored SE process for industrial plant based on ISO/IEC 15288 is used for the design of Continuous Casting Process (CCP) Plant system. The CCP is a crucial process in steel making plant, whose design technology is occupied by the advanced foreign companies. For the sake of increasing engineering capability for the design of CCP, we applied PSE Process for the renovation of the existing CCP Process. Through the study, we were convinced that the applied method can be used for other plant systems, and SE is really the way of thinking, design, and development of modern complex and multi-disciplinary systems where high risk factors are present throughout the whole life cycle.

• 디지털융복합연구
• /
• 제10권10호
• /
• pp.483-490
• /
• 2012

현대사회의 발전에 따라 삶의 질이 향상되면서, 귀금속보석은 사치품이라기보다는 패션의 일환으로 신변장식품이라는 의식변화와 함께 그 수요가 점점증가하고 있다. 인터넷(Internet) 등 멀티미디어(Multimedia)가 급속히 증가됨에 따라 파격적(破格的)인 디자인(Design)과 독특한 제품을 애용하는 인구가 늘어나고 있다. 그러나 앞으로는 한정된 천연보석의 고갈로 인하여, 천연보석만으로 그 수요를 감당할 수 없기 때문에 합성보석, 인조보석, 모조보석(模造寶石), 유기질, 물질 비경질 형태의 준(準) 광물(鑛物) 등(等)을 보석대용으로 사용한다. 그래서 합성보석의 대체성(代替性)은 필연적이기 때문에 다양한 합성보석, 유리( 琉璃)등의 소재가 개발되고 있고. 보석가공기술 및 독창적인 디자인개발이 뒤 따른다면, 합성보석에 대한 부가가치를 극대화 할 수 있다, 이에 따라 귀금속보석 산업에 있어서도 그 역할(役割)이 크게 기여(寄與) 할 것으로 본다. 세계 여러 나라는 귀금속보석 산업이 부를 추구 하는 효자산업으로 발전하고 있고, 우리나라도 2007년(年) 7월(月) 재경부가 우리나라의 귀금속보석 산업을 국가의 새로운 "신 성장 동력산업으로 육성 발전시켜 나가겠다는 귀금속보석 산업의 활성화정책"을 발표 하였다. 이에 본 연구는 귀금속산업의 활성화 방안을 찾아보기 위하여 합성보석을 이용한 보석 컷 디자인을 연구함으로써, 보석의 획일적(劃一的)인 연마형태(硏磨形態)에서 벗어나 독특하고 패션적인 커팅과 보석에 색상과 문양을 주어 다양한 보석디자인을 개발을 하고, 천연보석중심의 보석 디자인보다는 대중적이며, 많은 사람들이 함께 공유할 수 있는 합성보석을 이용하여 보석을 디자인 하였으며, 보석의 한정된 디자인 형태에서 벗어나 보석의 새로운 디자인을 발견하고 차별화된 제품을 생산함으로써 품질의 고급화로써 경쟁력(競爭力)을 확보(確保)하여 주얼리 디자인(Jewelry Design)의 창작영역 확대에 기여(寄與)하고자 보석 디자인 중심으로 연구를 하게 되었다.

• 한국공작기계학회논문집
• /
• 제13권1호
• /
• pp.100-106
• /
• 2004

All vehicles need the good quality of riding. Especially shifting shock is very important in the evaluation of the riding. Shifting shock is caused by transmission operation that one part and other part of gem are contacting together. This shock affect the feeling of driving. It is clear from these results that the shifting shock is affected by clutch pressure, pressure mode, inertia etc.

• 품질경영학회지
• /
• 제50권3호
• /
• pp.305-332
• /
• 2022

Purpose: As the public interest in entrepreneurship has been highlighted and entrepreneurship policies have been generated, this study is to construct Entrepreneurship Ecosystem (EE) models which have a significant relationship to national entrepreneurship with quantitative analysis. It aims to provide implications to EE policymakers that which national components are effective in cultivating innovative entrepreneurship and validate its EE quality based on quantitative performance goals. Methods: This study utilizes secondary data, categorized under the PESTLE factor from credible international organizations (WB, UNDP, GEM, GEDI, and OECD) to determine significant factors in the quality of the entrepreneurial ecosystem. This paper uses the Multiple Linear Regression (MLR) analysis to select the significant variables contributing to entrepreneurship performance. Using the AUC-ROC performance evaluation method for machine learning MLR results, this paper evaluates the performance of EE models so that it can allow approving EE quality by predicting potential performance. Results: Among nine hypothesis models, MLR analysis examines that the number of the Unicorn company, Unicorn companies' economic value, and entrepreneurship measured as GEI can be reasonable dependent variables to indicate the performance derived from EE quality. Rather than government policies and regulations, the social, finance, technology, and economic variables are significant factors of EE quality determining its performance. By having high Area Under Curve values under AUC-ROC analysis, accepted MLR models are regarded as having high prediction accuracy. Conclusion: Superior EE contributes to the outstanding Unicorn companies, and improvement in macro-environmental components can enhance EE quality.

• Nutrition Research and Practice
• /
• 제12권3호
• /
• pp.258-264
• /
• 2018

BACKGROUND/OBJECTIVES: Diet quality scores or indices, based on dietary guidelines, are used to summarize dietary intake into a single numeric variable. The aim of this study was to examine the association between the modified diet quality index for Koreans (DQI-K) and mortality among Health Examinees-Gem (HEXA-G) study participants. SUBJECTS/METHODS: The DQI-K was modified from the original diet quality index. A total of 134,547 participants (45,207 men and 89,340 women) from the HEXA-G study (2004 and 2013) were included. The DQI-K is based on eight components: 1) daily protein intake, 2) percent of energy from fat, 3) percent of energy from saturated fat, 4) daily cholesterol intake, 5) daily whole-grain intake, 6) daily fruit intake, 7) daily vegetable intake, and 8) daily sodium intake. The association between all-cause mortality and the DQI-K was examined using Cox proportional hazard regression models. Hazard ratios and confidence intervals were estimated after adjusting for age, gender, income, smoking status, alcohol drinking, body mass index, and total energy intake. RESULTS: The total DQI-K score was calculated by summing the scores of the eight components (range 0-9). In the multivariable adjusted models, with good diet quality (score 0-4) as a reference, poor diet quality (score 5-9) was associated with an increased risk of all-cause mortality (hazard ratios = 1.23, 95% confidence intervals = 1.06-1.43). Moreover, a one-unit increase in DQI-K score resulted in a 6% higher mortality risk. CONCLUSIONS: A poor diet quality DQI-K score was associated with an increased risk of mortality. The DQI-K in the present study may be used to assess the diet quality of Korean adults.

• 한국멀티미디어학회논문지
• /
• 제20권10호
• /
• pp.1662-1670
• /
• 2017

A-Scan NDT equipment is widely used in the industrial field because it is inexpensive and easy to carry but it is necessary to have a skilled inspection specialist who is trained to analyze the waveform of ultrasonic signal. Since the welding quality is judged subjectively by the specialist, there is a problem in the reliability of the quality. In the C-Scan NDT which overcomes the shortcomings of the A-Scan, welding part can be represented in the form of two dimensional image by combining one dimensional ultrasonic waveform so that the quality of welding can be grasped without the help of specialist. In order to develop C-Scan NDT, it is necessary to develop an array type two dimensional transducer and an algorithm to composing image by combining ultrasonic signals generated from a two dimensional transducer. In addition, the noise component must be minimized in the ultrasonic signal in order to display the quality of welding in the form of images. Therefore we propose a method to remove noise component from the ultrasonic wave and construct a two dimensional ultrasonic image.