• 한국자동차공학회논문집
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• 제8권5호
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• pp.1-11
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• 2000

This study is aimed to develop a proto-type LPG engine for medium-duty commercial vehicles in order to substitute for conventional diesel engine. Recently, it is recognized that diesel engines are main cause for smoke pollution in urban site. So, it is expected to reduce this environmental emission by developing and substituting LPG engine which has the advantage of practical use in a short development period in aspects of infrastructures. For that, after analysing the specifications and performance characteristics of a base diesel engine, parts of combustion chamber, intake system, fuel supply and ignition systems suitable for LPG combustion were re-designed and manufactured. And and engine controller for fuel supply and ignition distributions was matched by feedback mapping based on the speed-load conditions. The torque and power of LPG engine were increased by 6∼12% on the overall driving conditions compared to the base diesel engine, and fuel consumption rate marked the similar level based on the fuel price. Exhaust emissions such as THC, CO, NOx recorded the same order with conventional LPG engine for passenger car.

• 약학회지
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• 제51권3호
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• pp.199-205
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• 2007

Thermostable asparaginase was purified to homogeneity from mesophilic Strepfomyces lincolnensis M-20 by 30${\sim}$70% ammonium sulfate precipitation and asparagine-Sepharose CL 6B affinity column chromatography, The apparent molecular mass of L-asparaginase by SDS-PAGE was found to be 47 kDa, whereas by its mobility on Sephacryl S-300 column was around 180 kDa, indicating that the enzyme at the native stage acts as tetramer, The purified enzyme showed a single band on acrylamide gel electrophoresis. The optimum pH and temperature were pH 9.5 and 55${\circ}$C, respectively. Chemical modification experiments of purified asparagines implied the existence cystein residue located at or near active site. Purified asparaginase retained the 85% of the initial activity after incubation at 90${\circ}$C for 30 min. A correlation between themostability and resistance to proteolysis of commercial asparaginase and purified asparaginase from Strepfomyces lincolnensis M-20 was investigated. Purified thermostable asparaginase was resistant to trypsin and chymotrypsin treatment, while the commercial asparaginase was not themostable and was susceptible to proteolytic treatment with trypsin and chymotrypsin.

• 대한영양사협회학술지
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• 제22권4호
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• pp.310-319
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• 2016

Limitation of a questionnaire survey which is widely used is time and money, limited numbers of participants, biased confidence interval and unreliable results. To overcome these, we performed tendency and network analysis of diet using big Data in Koreans. The keyword on diet were collected from the portal site Naver from January 1, 2015 until December 31, 2015 and collected data were analyzed by simple frequency analysis, N-gram analysis, keyword network analysis and seasonality analysis. The results showed that diet menu appeared most frequently by N-gram analysis, even though exercise had the highest frequency by simple frequency analysis. In addition, keyword network analysis were categorized into four groups: diet group, exercise group, commercial diet program company group and commercial diet food group. The analysis of seasonality showed that subjects' interests in diet had increased steadily since February, 2015, although subjects were most interested indiet in July, these results suggest that the best strategies for weight loss are based on diet menu and starting diet before July. As people are especially sensitive to diet trends, researches are needed about annual analysis of big data.

• 한국환경보건학회지
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• 제27권2호
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• pp.1-9
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• 2001

This study was carried out to investigate the microbial characteristics of the urban air pollution in the subway stations, streets, department stores, wholesale markets, underground shopping centers, buildings, parks, houses and apartments in the Seoul and the suburbs area. Total cell count, total mold count and the presence of opportunistic pathogens(Streptococcus pneumoniae, Klebsiella pneumoniae, Aspergillus spp., Penicillium spp.) were evaluated determine the microbial air quality. Total cell count and mold count of indoor air in the houses and apartments were 2.9$\times$10$^2$-6.3$\times$10$^2$cfu/㎥ and 60-1.8$\times$10$^2$cfu/㎥, respectively, and the department stores and wholesale markets had much lower cell count than the houses and apartments. Ground level of commercial stations were 2.6 fold higher than the general subway stations, and Apergillus spp. and Penicillium spp. which could cause the bronchus and lung diseases were detected 17 sampling site out of 45. Dust were collected from the commercial facilities and houses, and total cell and mold count of the dust were 4.3$\times$10$^3$-1.7$\times$10$^{6}$ cfu/g and 2.3$\times$10$^3$-6.5 $\times$10$^4$cfu/g, respectively. Therefore the dust might be one of the main reservoir of microorganims.

• 한국정보시스템학회지:정보시스템연구
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• 제27권4호
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• pp.35-70
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• 2018

Purpose Recently, 3D factory simulation technology has emeged as a powerful tool for modeling and analysis of a wide range of production systems, however, it has been not paid much attention in Korea. In this context, this paper aims to provide a comprehensive literature review on discrete event simulation softwares and introduce a promising 3D factory simulation software called FlexSim and its application domains. Design/methodology/approach In order to demonstrate worldwide popularity and technical superiority of FlexSim software, we analyzed the recent list of rankings for commercial discrete simulation softwares released by winter simulation conference and users' opinions collected from business software review site. Moreover, several main application domains are derived from a review of the previous research papers that deal with applications of FlexSim software. Findings FlexSim software recently moved up the list of major commercial simulation softwares, and technical superiorities of the software demonstrate that it is a promising tool for practical 3D factory simulation. Moreover, recent research papers suggest that FlexSim software can be used as a component of smart factory system. In this context, it is expected that FlexSim software becomes more popular in the era of industry 4.0.

• 대한건축학회논문집:계획계
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• 제33권12호
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• pp.73-83
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• 2017

Due to the changes in the contemporary society, small-scale traditional markets have declined and lost their functions as the center of neighborhood commercial and cultural affairs. While most traditional markets are deteriorating, there exist rare cases of neighborhood small-scale traditional markets that continuously maintain their vitality and popularity. This paper examines urban spatial characteristics of those markets. As for the cases, this paper inventoried eighteen such markets in Gwanak-gu, Seoul. The research methods include literature reviews, on-site investigation of total 18 such markets, and participant observations. The findings of this paper are as follows: There are distinctive differences in the urban-spatial characteristics of physical environmental factors between the revitalized markets and declining markets. In terms of neighborhood and commercial environment, the franchised super-markets are not necessarily in competition with small-scale traditional markets. The former often has symbiotic relationship the latter, if the small scale traditional markets are strategically located in between residential areas and subway stations, providing active pedestrian networks. There are many outdoor display stands in the revitalized markets, while the declining markets rarely have them. The market improvement projects such as transforming the open space into arcade space, hardly have effects on revitalization of the small-scale traditional markets.

• 융복합기술연구소 논문집
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• 제11권1호
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• pp.33-37
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• 2021

The application of multicopters using a battery is limited by the short endurance due to the low energy density. A propeller is one of crucial components that determine the performance of the multicopter. In the present study, a systematic method for predicting the endurance of multicopters is described. Propeller performance database are constructed using the data from UIUC Propeller Data Site. Using the 'trendline' function of MS Excel software, the performance of the commercial propellers are represented as a function of polynomials. The multicopter's endurance is computed iteratively using Peukert's Law and considering the voltage drop effect. We evaluated the endurance of multicopters that use commercial propellers. The endurance of the multicopter was within the range of 28 min. to 36 min. It is expected that the present method can be utilized for optimal propeller selection for the given multicopters.

• 풍력에너지저널
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• 제15권1호
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• pp.50-59
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• 2024

Floating LiDAR systems provide significant savings in cost and time compared to the fixed meteorological mast measurement type, and have the advantage of being able to be deployed in various locations due to less restriction on the depth of the installation site. However, to use the wind data collected by a floating LiDAR system commercially, verification procedure is required to ensure that the collected data have sufficient availability. The Carbon Trust OWA roadmap presents guidelines in three stages for the reliability of the wind data collected using a floating LiDAR system. Companies developing wind farms are requesting at least Stage 2 (pre-commercial stage) presented by OWA, and many overseas companies are leading the domestic and overseas markets. In this paper, we introduce the case of OWA Stage 2 certification for the commercial operation of floating LiDAR systems.

• 한국산학기술학회논문지
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• 제17권8호
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• pp.698-705
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• 2016

본 연구의 목적은 택지개발사업의 계획특성이 사업지구의 지가변동에 미치는 영향을 분석하여 택지개발사업의 효율적인 추진을 위한 정책적 시사점을 도출하는 것이다. 이를 위해 우선 청주시 택지개발사업 추진단계별 지가변동 규모와 양상을 분석하였다. 그리고 이론적 고찰 및 선행연구 검토를 통해 지가변동에 영향을 주는 택지개발사업의 계획특성 요소 16개((1)지가변동률, (2)사업구역 면적, (3)주거용지 비율, (4)상업용지 비율, (5)준주거용지 비율, (6)근린생활시설용지 비율, (7)공동주택 비율, (8)도로율, (9)공원 녹지율, (10)학교 비율, (11)$1m^2$당 조성비, (12)일반주거지역 비율, (13)준주거지역 비율, (14)상업지역 비율, (15)준공업지역 비율, (16)자연녹지지역 비율)를 선정하였다. 선정된 계획특성 요소 16개 중 지가변동에 영향을 미치는 요인을 분석하기 위하여 SPSS 20.0 Version을 이용하여 상관관계를 분석하였다. 지가변동의 양상을 분석한 결과, 지구가 지정되기 2년 전부터 지가가 상승되기 시작하였고 준공이후 지가상승이 안정화되는 것으로 분석되었다. 그리고 지가변동에 영향을 주는 계획특성 요소를 분석한 결과 (2)사업구역 면적, (4)상업용지 비율, (6)근린생활시설용지 비율, (8)도로율, (11)$1m^2$당 조성비, (12)일반주거지역 비율이 지가변동에 영향을 미치는 것으로 분석되었다.

• 한국경영과학회지
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• 제33권3호
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• pp.59-76
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• 2008

Studies of recommender systems have focused on improving their performance in terms of error rates between the actual and predicted preference values. Also, many studies have been conducted to investigate the relationships between customer information processing and the characteristics of recommender systems via surveys and web-based experiments. However, the actual impact of recommendation on product pages for customer browsing behavior and decision-making in the commercial environment has not, to the best of our knowledge, been investigated with actual clickstream data. The principal objective of this research is to assess the effects of product recommendation on customer behavior in e-Commerce, using actual clickstream data. For this purpose, we utilized an online bookstore's clickstream data prior to and after the web site renovation of the store. We compared the recommendation effects on customer behavior with the data. From these comparisons, we determined that the relevant recommendations in product pages have positive relationships with the acquisition of customer attention and elaboration. Additionally, the placing of recommended items in shopping cart is positively related to suggesting the relevant recommendations. However, the frequencies at which the recommended items were purchased did not differ prior to and after the renovation of the site.