• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.15 no.5
• /
• pp.71-82
• /
• 2016

Information System for rear-end collision avoidance is a unit service of C-ITS pilot project. Road environment that the number of vehicles at the same driving high-speed has a possibility that the communication delay or failure caused by heavy load of vehicle to vehicle communication. In this study, effects of the road network about a communication failure rate of information system for rear-end collision avoidance was analyzed quantitatively with micro traffic simulation. The simulation was carried out in situation that crash of two vehicles are occurred at merging area with speed limit 80km/h and information of collision is prvoided to the rear vehicle. From simulation results, it can confirm the trend of the increasing 14% of potential conflict according to 10% increasing of the communication failure rate. C-ITS service has a goal of increasing safety. The coommunication failure rate increases due to heavy load of vehicle causes a fatal result in road safety administrator position. For the success of C-ITS project, a communication system developers side should perform the effort to reduce the communication failure rate.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.11
• /
• pp.7736-7744
• /
• 2015

Considering the significant waste of industrial energy, effective use of low temperature waste heat is extremely important. In this study, a heat pump cycle with double effect and double stage was realized, which escalates the hot water temperature from $50^{\circ}C$ to $70^{\circ}C$ using $160^{\circ}C$ high temperature heat source and $17^{\circ}C$ low temperature heat source. The steam generated in the first generator condenses in the first condenser generating steam in the second generator. The steam condenses in the second condenser and is provided to the second evaporator. Part of the water out of the second evaporator is supplied to the first evaporator, which evaporates using low temperature waste heat. The evaporated steam enters the first absorber and the second evaporator. The steam out of the second evaporator is absorbed into the solution at the second absorber. The hot water temperature is raised in the second condenser and in the second absorber. Proper flow rates and UA values, which satisfied temperature lift $20^{\circ}C$ and COP 1.6, were deduced through trior and error. The COP increases as the temperature of the high temperature water increases, hot water temperature decreases and flow rate increases, waste water temperature and flow rate increases, solution circulation rate decreases. On the other hand, the temperature rise of the hot water increases as the temperature of the high temperature water increases, hot water temperature increases and flow rate decreases, waste water temperature and flow rate increases, solution circulation rate increases. In addition, the COP and hot water temperature rise increase as UAs of the heat exchangers increase.

• Journal of Korean Society for Geospatial Information Science
• /
• v.21 no.3
• /
• pp.37-46
• /
• 2013

Similarity measure of catchments is essential for regionalization studies, which provide in depth analysis in hydrological response and flood estimations at ungauged catchments. However, this similarity measure is often biased to the selected catchments and is not clearly explained in hydrological sense. This study applied a type of hydrological similarity distance measure-Flood Estimation Handbook to 25 Geum River catchments, Korea. Three Catchment Characteristics, Area(A)-Annual precipitation(SAAR)-SCS Curve Number(CN), are used in Euclidian distance measures. Furthermore, six index of Flow Duration Curve are applied to clustering analysis of SPSS. The catchments' grouping of hydrological similarity measures suggests three groups (H1, H2 and H3) and the four catchments are not grouped in this study. The clustering analysis of FDC provides four Groups; F1, F2, F3 and F4. The six catchments (out of seven) of H1 are grouped in F1, while Sangyeogyo is grouped in F2. The four catchments (out of six) of H2 are also grouped in F2, while Cheongju and Guryong are grouped in F1. The catchments of H3 are categorized in F1. The authors examine the results (H1, H2 and H3) of similarity measure based on catchment physical descriptors with results (F1 and F2) of clustering based on catchment hydrological response. The results of hydrological similarity measures are supported by clustering analysis of FDC. This study shows a potential of hydrological catchment similarity measures in Korea.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.2
• /
• pp.229-237
• /
• 2016

The purpose of this paper is to empirically identify whether unit bias exists or not under the flat rate pricing in the Korean mobile telecommunication market and to give the desirable form of pricing plans for minimizing this irrational behaviors. Our results show that with the flat rate pricing consumers tends to make more voice or data traffic over their optimal consumption level, meaning the existence of unit bias in the Korean mobile market. These results imply that under the current pricing plans subscribers may pay higher monthly fee than their optimal cost which maximizes their utility, for using the telecommunications service. Thus, policy makers need to consider adopting mobile operators' segmentation of the flat rate pricing plans for the reduction of subscribers' telecommunications costs and the improvement of consumer welfare.

• Journal of the Korea Society of Computer and Information
• /
• v.17 no.2
• /
• pp.139-147
• /
• 2012

In this paper, we discuss the structure of biological knowledge discovery system based on text mining and automatic inference. Given a set of biology documents, the system produces a new hypothesis in an integrated manner. The text mining module of the system first extracts the 'event' information of predefined types from the documents. The inference module then produces a new hypothesis based on the extracted results. Such an integrated system can use information more up-to-date and diverse than other automatic knowledge discovery systems use. However, for the success of such an integrated system, the precision of the text mining module becomes crucial, as any hypothesis based on a single piece of false positive information would highly likely be erroneous. In this paper, we propose a probabilistic filtering method that filters out false positives from the extraction results. Our proposed method shows higher performance over an occurrence-based baseline method.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.2
• /
• pp.107-113
• /
• 2014

The derivation of optimal information from decision table is based on the concept of indiscernibility relation and approximation space in rough set. Because decision table is more likely to be susceptible to the superposition or inconsistency in decision table, the reduction of attributes is a important concept in knowledge representation. While complete subsets of the attribute's domain is considered in algebraic definition, incomplete subsets of the attribute's domain is considered in information-theoretic definition. Therefore there is a marked difference between algebraic and information-theoretic definition. This paper proposes a conditional entropy using rough set as information theoretical measures in order to deduct the optimal information which may contain condition attributes and decision attribute of information system and shows its effectiveness.

• Journal of Korean Society of Forest Science
• /
• v.65 no.1
• /
• pp.107-112
• /
• 1984

Theoretical studies on the effects of forest road are considered to be significant from a present viewpoints which is headed for mordernization and activation of forestry. 1) From a viewpoint of wood production techniques, forest road is enable to economical transport of all kinds of forest products and easy transport to forest of operative tools and necessary materials, and largely contribute to efficiency of all operations, including reforestation, tending, forest protection and conservation of forests. 2) And, from a viewpoint of forest management, development of forest road makes wood marketability be secured and curtailment of various indirect expenditure with the operation efficiency be possible. 3) Forest road, also in living aspects of inhabitants in mountainous villages, plays direct and indirect roles in promoting their welfare including improvement of employment for forest labor, traffic benefits in mountainous area and introduction of culture. Therefore, as a premise to realize intensive management in forestry, the necessities of forest road were increased in its aspects of important and fundamental facilities as well as production basis.

• CRM연구
• /
• v.2 no.2
• /
• pp.21-40
• /
• 2009

This study conducted to examine how consumer's perception of COO(Country of (Brand) Origin) image affects brand association knowledge, how coo image and brand association knowledge affect buying intention, how these relationship differs in hedonic and utilitarian products and the moderating effect of consumer's ethnocentrism in the influence of brand association to buying intension. The results indicated the followings: First, it was significant COO Image affect brand association knowledge, more strong significant in Hedonic products than in utilitarian products. But it was not supported COO Image affect buying intension significantly. Second, Brand association knowledge affected buying intention significantly. And the last, consumer's ethnocentrism mediated between brand association knowledge and buying intention strong significantly.

• Journal of Gifted/Talented Education
• /
• v.19 no.2
• /
• pp.381-404
• /
• 2009

The purpose of the study was to find out the usefulness of teachers' recommendation in selecting gifted students. For the study 87 teachers teaching 4th grade students from 20 elementary schools in the area of Incheon, 103 gifted students who were recommended by teacher, and 65 gifted students who were not recommended by teacher participated. To measure their cognitive ability, Raven intelligence test, creative problem solving test in science, and TTCT were used. In addition, learning methods, motives for achievement, faith in academic ability, problem solving tendency, and assignment preferences were assessed to find out their affective qualities. The results were as follows. First, the students who were recommended by teachers were highly advanced in both cognitive and affective aspects related to giftedness compared to non recommended students. Second, there were no significant differences both in the cognitive and affective aspects among the students recommended by teachers whether they passed the second step(test for giftedness) and the third step(test for academic aptitude) or not. Third, the discriminant analysis showed $70{\sim}80$ percent accuracy on teacher recommendation in identifying gifted students. The implication of the study related to teacher recommendation and future direction on identification of gifted students were discussed in depth.

• Journal of Digital Convergence
• /
• v.17 no.9
• /
• pp.97-104
• /
• 2019

With the development and spread of smart devices, the proportion of mobile shopping is gradually increasing, and the market for mobile gift certificates is also increasing. This study examines the usage status and acceptance attitude of mobile gift certificates for university students who are major customers of mobile gift certificates. Also, based on the extended integrated technology acceptance model (UTAUT2), the results of the analysis of the mediating effect of the intention of the user on the relationship between acceptance of mobile vouchers and recommendation intention were presented. As a result of the analysis, it was shown that the effort expectation, hedonic motivation, price utility, and habit had significant influence on the intention to use the mobile gift certificates. Also, the intention to use mobile gift certificates has mediating effects between effort expectation, hedonic motivation, price utility and recommendation intention. The results of this study can be applied to strategic marketing such as recruitment of new customers through mobile gift certificates while explaining customers' acceptance of technology to mobile gift vouchers or future prospective customers.