• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.174-182
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• 2007

There are not many studies on the maintenance and replacement for the ITS equipments. Most of ITS center has no comprehensive regulation on the equipment replacement. This study was focusing on estimation of equipment replacement period and the number of spare parts in stock using the actual failure data of Road Side Equipment (RSE) by Dedicated Short Range Communication (DSRC). The failure data showed a type of bath-tub curves. The data, however, did not fit to any probability distribution curve, which means that the preventive replacement cannot be strongly applied for the RSE. In the aspect of practical strategy, this study suggest that repairing cost and failure frequency be used for decision of replacement of RSE after the 1 or 2 year warrant period. The future study needs to include more RSE failure data as well as other equipments of the ITS.

• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.251-260
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• 2017

The option pricing of Black와 Scholes (1973) and Merton (1973) has been widely reported to fail to reflect the time varying volatility of financial time series in many real applications. For example, Duan (1995) proposed GARCH option pricing method through Monte Carlo simulation. However, financial time series is known to follow a fat-tailed and leptokurtic probability distribution, which is not explained by Duan (1995). In this paper, in order to overcome such defects, we proposed the option pricing method based on GARCH models with normal mixture errors. According to the analysis of KOSPI200 option price data, the option pricing based on GARCH models with normal mixture errors outperformed the option pricing based on GARCH models with normal errors in the unstable period with high volatility.

• Proceedings of the Korea Association of Information Systems Conference
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• 1997.10b
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• pp.111-136
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• 1997

정보시스템 기획(IS planning)은 경영환경의 변화로부터 야기되는 조직의 정보요구 를 제대로 파악함으로써 새로운 정보시스템의 구축이나 실행과정에 반영하는 중요한 과업중 의 하나이다. 하지만, 아직까지 정보요구를 반영한 정보시스템 기획유형에 관한 연구나 정 보시스템 기획의 효과성에 관한 영향에 대한 실증적인 연구가 없었다. 그리하여, 본 연구에 서는 기업의 경쟁력 강화 목표를 달성하기 위해 필요한 정보시스템의 효율적인 관리와 활용 을 위하여 정보시스템 기획에 관한 상황 이론적 접근을 시도하였다. 본 연구는 과업환경을 중심으로 발생하는 정보요구의 유형에 따라 정보시스템 계획을 어떻게 추진하는 것이 바람 직한 것인지를 파악하고, 정보시스템을 기획 시 정보요구 수준과의 적합성(fitness)에 따라 정보시스템 기획의 효과성은 어떻게 달라지는 지를 파악하고자 한다. 이를 위하여 본 연구 에서 사용된 Construct와 변수들은 기존의 정보시스템 기획관련 문헌을 이용하였다. 본 연 구를 위하여 국내 매출액 1000대 기업을 대상으로 설문지를 우송하였으며, 그 중 187부가 회수되었다. 자료분석의 결과, 정보요구 수준과 정보시스템 기획유형간의 관련성은 긍정적 으로 관련되어 있었으며, 정보요구 수준에 따른 기획의 효과성에는 차이가 없었으나, 정보 시스템 기획유형에 따른 기획의 효과성은 유의한 차이가 있었다. 특히, 정보요구 수준과 정 보시스템 기획유형간의 적합성에 의한 정보시스템 기획의 효과성에 대한 t-test결과는 적합 한 조직(fit organization)보다는 적합하지 않은 조직(unfit organization)의 성과가 더 높은 것으로 나타났다.성 형질전환 계통의 식물체 내에서의 바이러스 증식 및 이동과 관련된 저항성 기작, 여러 가지 PVY 계통에 대한 저항성 유무, 수량, 생육 특성 및 주요 화학 성분 함량 등을 발표하고자 한다.-glucose로 구성된 다당류 이었다. 아미노산은 Asp 및 Glu의 산성 아미노산과 Ala, Leu 등의 함량이 높게 나타났으며, 비알칼리 추출물에서 Ser과 Thr의 함량이 높게 나타났다. 다당류 T-AS는 평균 분자량이 2,000 kD와 12kD에서 주 peak를 나타냈으며, 수용성 분획의 평균 분자량은 12kD이고 비수용성 분획은 36~2,000 kD의 평균 분자량 분포를 갖는 것으로 나타났다. IR과 NMR 분석 결과 890 cm-1에서 흡수 peak를 나타내어 $\beta$-(1,3)0glucan과 $\beta$-(1,6)-glucan의 구조를 갖는 다당류로 확인 되었다. T-AS 분획은 C:H:O:N의 함량비가 38.9:5.7:49.6:1.84%이며, 이 물질의 융점은 163 $^{\circ}C$로 연한 갈색을 나타낸다. 분리된 GLG의 항암활성 기전 규명을 위해, in vivo 항암실험, 항보체 활성능, 항체 생성능, serum protein 분비능, 대식세포의 탐식능과 활성능 및 세포간 물질 분비 등의 상관관계를 조사하였다. 다당류 GLG 분획물들 가운데 항보체의 활성이 높았던 분획은 sarcome 180에 대한 항암 활성이 높게 나타났다. 다당류 T-AS의 보체 활성화 기작은 classical과 alternative complement pathway의 양 경로를 통해 활성화 되었다. T-AS 분획은 mouse내의 특정

• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.104-107
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• 2007

현재까지 수리학 분야에서 가장 많이 회자되고 인용된 공식이 있다면 아마도 1800년에 발표한 Manning의 유속 공식이라고 해도 과언은 아닐 것이다. 그만큼 그 쓰임새가 많았을 뿐만 아니라 사용의 편리생과 정확도에서도 매우 우수하였기 때문일 것이다. 그러나, 아무리 우수한 공식이라도 약점이 있듯이, Manning의 유속공식 역시 조도계수n을 추정하는데 많은 어려움이 있는 것도 주지의 사실이다. 이러한 어려움을 극복하기 위하여, 본 연구에서는 확률통계에서 사용되는 엔트로피 개념을 이용한 3차원 유속분포식인 Chiu의 유속공식을 사용하였다. 그러나 지금까지 실증적으로 Chiu의 유속공식과 Manning땅의 유속공식을 비교분석하였던 논문은 Chiu와 Choo의 논문에서 일부 언급된 것 외 논문에서는 찾아볼 수 없는 것이 현실이다. 따라서 본 연구에서는 하상경사를 임의로 변경 가능한 실험수로를 선택하여 정밀법에 의한 유속측정을 우선 실시하였다. 같은 지점의 같은 단면에서 하상경사(${\Theta}$)가 0.000935부터 0.025794까지 28번의 경사변화를 주고 각 경사마다 유량을 측정하여 28개의 유량측정 데이터를, Chiu의 유속공식과 Manning의 유속공식에 각각 적용하여, Chiu의 M과 Manning의 n사이의 관계뿐만 아니라, 하상경사변화에 따른 관련인자들을 함께 분석하였으며, 실측된 평균유속과도 함께 분석하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.5
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• pp.563-569
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• 2012

The studies of opinion mining or sentiment analysis have been the focus with social web proliferation. Sentiment analysis requires sentiment resources to decide its polarity. In the existing sentiment analysis, they have been built resources designed with intensity of sentiment polarity and decided polarity of opinion using the ones. In this paper, I will present sentiment categories for not only polarity of opinion but also the basis of positive/negative opinion. I will define psychological emotions to primary sentiments for the reasonable classification. And I will extract the informations of sentiment from social web texts for the actual distribution of sentiments in social web. Re-classifying primary sentiments based on extracted sentiment information, I will organize sentiment categories for the social web. In this paper, I will present 23 categories of sentiment by using proposed method.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.2
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• pp.76-88
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• 2017

The urban park plays important roles in protecting the urban landscape and improving citizens' health, recreation, and the emotional life. Above and beyond these roles, the urban park is expected to rearrange urban spatial structures as a kind of urban system. The purpose of this paper is to identify empirically to change urban spatial structures by construction of the urban park. This study regards gentrification around the urban park as a process to change urban spatial structures. The gentrification means the regeneration and upgrading of deteriorated urban property by the middle class or commercial developers. The site of case analysis is the Seoul Forestry Park in Sungdong-gu, Seoul. The Seoul Forestry Park is regarded as a representative urban park of Seoul, and caused gentrification around park after the 2005 opening. This study operationally defines the gentrification index and the accessibility index from an urban park and offers an empirical analysis of relation among the urban park, the gentrification and urban spatial structure in a statistic district which is the minimum unit of Korean statistic data in 2000, 2005, and 2010, using Difference-in-Difference method and linear probability model. The results of this empirical study show that the Seoul Forestry Park changes urban spatial structures by gentrification. It reverses a trend of migration of gentrifiers before and after construction of the Seoul Forestry Park. It suggests urban park construction as an alternative method for urban regeneration by inducing the middle class into the inner city of Seoul.

• Environmental and Resource Economics Review
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• v.16 no.2
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• pp.337-361
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• 2007

Using the sample of bituminous coal prices, this study calculates the cash flows of selective procurement strategies compared to the previous routine procurement strategies, and analyzes the revenue-improvement and revenue-stabilization effects of different procurement strategies. In empirical analyses, these effects of routine and selective procurement strategies are compared by forecasting model and forecasting period. The revenue-improvement and revenue-stabilization effects are analyzed to compare the distribution of return flows, that is the means and standard deviations of procurement revenue flows. The revenue-improvement and revenue-stabilization effects of selective procurement strategies compared to the previous routine procurement strategies are as follows. Compared with routine procurement strategies, the selective procurement strategies turn out to yield higher means of returns (except for some forecasting periods and models). On the contrary, the standard deviations of returns decrease. With longer forecasting periods, the amounts of increases in the means become larger, but the degrees of decreases in the standard deviations vary. Although there exist some variations, some forecasting models outperform the others in terms of means and standard deviations.

• Journal of the Economic Geographical Society of Korea
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• v.25 no.1
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• pp.131-146
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• 2022

The purpose of this study is to examine the locational characteristics of cafes in Jeju Island and the changes. For the purpose, we identify the spatial distribution patterns of openings and closings by period from the first opening of cafes in Jeju Island to the present. In particular, we analyze the spatial distribution characteristics found in the locations of cafes that have been opened and closed after the outbreak of COVID-19, in which new stores have significantly increased. In addition, we identify the regional attributes and the influence of online that have affected the distribution of currently open cafes and cafes that have opened or closed during the COVID-19 outbreak. As a result of empirical analysis, Jeju Island is a tourist destination and island region with the characteristics of determining major destinations through information search, showing a different distribution form from the location of cafes in inland cities. In particular, as a result of frequency analysis by extracting keyword search volume for cafes in Jeju Island, online accessibility such as information search for new areas and places in Jeju Island has become more diversified and expanded after COVID-19. In addition, as a result of calculating the distance to cafes by road size, the relationship between physical location and road accessibility, which has traditionally been an important factor, was relatively low. This study is meaningful in that it revealed the distribution patterns and characteristics of cafe locations in Jeju Island by reflecting the influence of online and offline.

• Journal of Korean Society of Transportation
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• v.36 no.3
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• pp.184-194
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• 2018

Recently, the need to introduce bus lines on a welfare basis is increasing as public intervention in bus routes is accelerated through semi-public bus system. The main objective of this study is to establish the concept of PSO (public service obligation) bus line on a welfare basis and propose a classification method of PSO bus line under semi-public bus system. We introduced 3 indexes such as "equity" in terms of bus line distribution, "publicity" in terms of age distribution, and "profitability" in terms of bus operating revenues. On the basis of 3 indexes, we introduced the PSO bus line, which is fair and public, even if it is not profitable. Based on the concept established in this study, we divided 130 ordinary city bus lines in Busan Metropolitan City into 8 PSO bus lines. Also, considering the positive impact of public buses, which are less profitable, but improve the mobility of residents and secure public community, we suggested the need to introduce public buses in bus service shortage areas.

• Journal of the Korean Regional Science Association
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• v.34 no.2
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• pp.35-47
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• 2018

This research aims to examine the spatial patterns of vacant housings and the factors determining housing vacancy in Daegu using individual-level building DB. The results of the spatial pattern analysis showed a donut shaped-spatial concentration of vacant housings in the central areas of the city. The results of logistic regression analysis revealed that not only individual building characteristics, such as building area, number of floors, and building age, but also socio-economic characteristics of community, such as urban redevelopment district, number of adjacent vacancies, recent population change, and ratio of elderly, are important factors affecting housing vacancies.