• Journal of The Korean Association For Science Education
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• v.35 no.4
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• pp.665-676
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• 2015

In this case study, we analyzed the processes of STEAM lessons conducted by preservice secondary science teachers. Three preservice science teachers at a college of education in Seoul participated in this study. After the workshop for STEAM education, they planned and practiced STEAM lessons. All of the teaching-learning materials were collected before lessons, and their lessons were observed and videotaped. Semi-structured interviews were also conducted before and after their lessons. The processes of STEAM lessons were analyzed while focusing on PCK and PDC. Their difficulties, needs, and views on STEAM education were also studied. It was found that they have taken much efforts to reflect the objectives and characteristics of STEAM education, and prepared teaching-learning materials by searching on the internet and arranging creative contents. Their great difficulty was to determine topics for STEAM lessons. While one preservice teacher satisfied with her lesson perceived STEAM education positively, the others perceived that it would be very difficult to practice STEAM lessons in school. For their STEAM lessons to be successful, the workshop needs to include some specific information on grades, proper topics for each grade, ways of making materials, and tips for effective STEAM lessons. In addition, it will be effective if the workshop is carried out after their study on constructivist learning theory and if they experience successful STEAM lessons.

• 대한공업교육학회지
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• v.42 no.1
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• pp.125-139
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• 2017

The purpose of this study was to provide a basic research data for increasing the satisfaction by analyzing perception of middle school beginning technology teachers 'technology home economics' class for free semester program. In order to investigate the class operation status, the survey questionnaires from 100 teachers were collected from middle school beginning teachers who teach technology home economics subject currently and analyzed by statistical program(SPSS ver.18). The main results of this study were as follows: First, there was no statistically significant difference to contents and satisfaction of lesson between teachers who experienced free semester program and not. In comparison of male teachers and female teachers, male teachers thought that free semester program was more helpful for student's 'career exploration' than female teachers, and there was statistically significant difference. Second, in the teacher's response according to have practice space and not, the satisfaction average of teachers who have practice space was higher(M=3.64) than those who have not at 'career exploration' and there was statistically significant difference satisfaction. Third, among the teachers who have experienced free semester program, male teachers were having more difficulty 'determining the assessment criteria' than the female teachers and there was statistically significant difference. Fourth, to improve the satisfaction of technical lesson, technology teachers asked to solve lack of practice material, increase of lesson-time, lack of practice space and lesson contents etc. Fifth, technology teachers asked free semester program seminars and information because free semester program lesson contents was given by internet and research groups of technology education.

• Journal of Korean Society for Geospatial Information Science
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• v.25 no.2
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• pp.3-12
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• 2017

Leaving positive or negative comments of places where he or she visits on location-based services is being common in daily life. The sentiment analysis of place reviews written by actual visitors can provide valuable information to potential consumers, as well as business owners. To conduct sentiment analysis of a place, a spatial sentiment lexicon that can be used as a criterion is required; yet, lexicon of spatial sentiment words has not been constructed. Therefore, this study suggested a method to construct a spatial sentiment lexicon by analyzing the place review data written by Korean internet users. Among several location categories, theme parks were chosen for this study. For this purpose, natural language processing technique and statistical techniques are used. Spatial sentiment words included the lexicon have information about sentiment polarity and probability score. The spatial sentiment lexicon constructed in this study consists of 3 tables(SSLex_SS, SSLex_single, SSLex_combi) that include 219 spatial sentiment words. Throughout this study, the sentiment analysis has conducted based on the texts written about the theme parks created on Twitter. As the accuracy of the sentiment classification was calculated as 0.714, the validity of the lexicon was verified.

• The KIPS Transactions:PartB
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• v.10B no.2
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• pp.143-150
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• 2003

Error concealment plays an important role in combating transmission errors. Methods of error concealment which produce better quality are generally of higher complexity, thus making some of the more sophisticated algorithms is not suitable for real-time applications. In this paper, we develop temporal and spatial error resilient video encoding and data hiding approach to facilitate the error concealment at the decoder. Block interleaving scheme is introduced to isolate erroneous blocks caused by packet losses for spatial area of error resilience. For temporal area of error resilience, data hiding is applied to the transmission of parity bits to protect motion vectors. To do error concealment quickly, a set of edge features extracted from a block is embedded imperceptibly using data hiding into the host media and transmitted to decoder. If some part of the media data is damaged during transmission, the embedded features are used for concealment of lost data at decoder. This method decreases a complexity of error concealment by reducing the estimation process of lost data from neighbor blocks. The proposed data hiding method of parity bits and block features is not influence much to the complexity of standard encoder. Experimental results show that proposed method conceals properly and effectively burst errors occurred on transmission channel like Internet.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5B
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• pp.456-477
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• 2006

Due to advances in wireless communication technology and increasing demand for various types of wireless access, cellular, WLAN, and portable internet(such as WiBro and IEEE 802.16) systems are likely to be integrated into a unified wireless access system. This expectation premises the availability of multi-mode handsets and cooperative interworking of heterogenous wireless access networks allied by roaming contracts. Under such environments, a user may lie in the situation where more than one wireless accesses are available at his/her location, and he/she will want to choose the 'best' access among them. In this paper, we define the 'best' access(es) as the access(es) that charges minimum cost while fulfilling the required QoS of wireless access, and address the problem of choosing the optimal set of accesses theoretically by introducing a graph representation of service environment. Two optimal selection algorithms are proposed, which individually consider cases where single or multiple wireless access can be supported by multi-mode handsets.

• Journal of KIISE:Information Networking
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• v.32 no.1
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• pp.20-28
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• 2005

TCP(Transmission Control Protocol) is one of the most important Internet protocols, which is widely used in wireless networks as well as wired networks. However, when TCP is deployed for wireless networks, it takes severe performance degradation because TCP was designed for wired network. To overcome this drawback, a number of TCP variants have been proposed in the literature. However, most previous schemes did not consider TCP enhancement over heterogeneous networks. In heterogeneous networks, an mobile node (MN) may move from one access network to another(i.e., vertical handover). In the case of vertical handover, an MN experiences a TCP performance degradation caused by the packet loss and the sudden change of link characteristics between two different access networks. In this work, we investigate the TCP performance degradation occurred in vortical handover across heterogeneous networks. First, we have conducted the measurement study over GPRS-WLAN testbed. In the measurement study. we observed the TCP performance degradation in the case of handover from WLAN to GPRS. In order to study more different TCP behaviors during vertical handover, we performed comprehensive simulations using a network simulator 2(ns-2). Based on measurement and simulation results, we investigated how to improve TCP performance in vertical handover and we concluded that the existing mechanisms cannot be perfect solutions and new mechanisms are strongly required.

• Journal of Distribution Research
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• v.15 no.5
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• pp.81-102
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• 2010

The present study analyzes the choice factors and possibility of traditional and other competing markets through consumer behavior analyses in order to suggest factors that can help reactivate traditional markets. Hence, Multinomial Logit Model is used as it is an optimum model to understand discrete selection. The results suggested some tendencies regarding traditional market. For example, traditional market is more activated when the market is large and has more parking spaces, and when the level of consumer satisfaction is high. While, increased travel distance and time have negative effects on visitor's choice. Governmental supports are turned out to have less to do with the consumer attraction. People with higher incomes tend to prefer other types of market. The results also suggested there is more likelihood of traditional markets being reactivated if the market is not fiercely competing with other types of markets. Internet market is ranked top in consumer's choice possibility, while traditional market is ranked at the bottom. The plausible factors to reactivate traditional market were physical factors(including increasing shops and parking facilities), which is followed by governmental support.

• Archives of design research
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• v.16 no.1
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• pp.35-44
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• 2003

In the past era, acquisition and utilization of useful information was the main origin of competition. Nowadays, unlike that era, is the era of knowledge information(management) in which we should create a new knowledge on the basis of information and apply it to the field of practice. And more acquisition of information is no more the competitive power of any person, any company and any nation because in such the era of knowledge management, anyone can access and get the information he needs, utilizing internet-based searching system. Such demands of the times of knowledge management change rapidly in each field through knowledge management system and researches about knowledge management are actively processed in various academic branches. However, in our field of design, researches about those demands(knowledge management) still remain on the level of one-dimensional searching service for general data about design. Therefore, in this study, we developed building database of researches on form, color, aesthetical elements, preference image word, satisfaction etc. about CI/BI of home electronics goods, living goods, apparels, and food goods companies, also suggesting searching system through which you can obtain useful data and information helpful for designers to process CI/BI works of new product by using that database. Especially, in case of developing specific CI/BI, various search results through help of suggested system will supply a useful design concept. And more, cross table which is the result of analysis two-dimensional categorical data about existing design factors(such as form, color, aesthetical elements, preference image word, and satisfaction) will make contribution for designers to create a new design knowledge.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.2
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• pp.77-86
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• 2008

The information of university entrance examination is important information to examinees as well as each universities. And this information can be used various fields. By using this information, examinees can choose the university which is most suitable regions through oneself's grade, and universities can decide the entrance policy and public relations of university. Furthermore, this information can be used important data to promote student's welfare. Therefore the introduction of College Matriculation System which can share between examinees and universities is keenly required. This study has developed the College Matriculation System which is Web2.0- based by using Naver Map API. By using this system, the information about candidates, and successful candidates and registrants for admission can be analysed, also the ratio of successful candidates in comparison with candidates and the change ratio of candidates during these three years can be analyzed. Besides, it can be supported the entrance public relations policy of universities by managing the public relations history, and it can be provided the information of university by grade to examinees on matriculation information based. Therefore, it was possible that manage and practical use of various data through connected with map based on web 2.0 which is opened. And it is considered possible to express more various information based on map constructing GIS system of user center that is not GIS system of existent offerer center.

• Journal of the Korean Geographical Society
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• v.48 no.5
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• pp.686-708
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• 2013

The goal of this investigation is to examine the matter as to how various cyberpolitical activities such as on-line civic participation, cyber parties, development and movement of civil society networks are appeared in cyberspace; and how political activities in cyberspace are associated with offline environment. This research was based on in-depth and open-ended interviews centering around 20s (32 interviewees) and the major results are as in the following. First, in terms of on-line civic participation, searching political issues occur in places, where internet users can access information easily relatively, and creating or reconstructing political information is identified in places giving stability or affinity to the public society. Second, even though each party's homepage for the channel of cyber parties has enough capacity as bridgespace, which takes charge of supporting f lows of people, goods, capital, and ideas, most of them don't play a role to establish virtual or real networks. Exceptively, cyber parties contribute to make temporalized places, where nobody takes the responsibility, somewhat. Third, the development and movement of civil society networks is divided into several segments according to political interests and tendency in online; furthermore, such a cyberpolitical activity influences human networks and the decision of major places for political activities in offline.