• The KIPS Transactions:PartD
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• v.12D no.4 s.100
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• pp.521-530
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• 2005

Many researches are going on with regard to issues and problems related to mobile database systems, which are caused by the weak connectivity of wireless networks, the mobility and the Portability of mobile clients. Mobile computing satisfies user's demands for convenience and Performance to use information at any time and in any Place, but it has many Problems to be solved in the aspect of data management. The purpose of our study is to design Mobile Query Processing System(MQPS) to solve problems related to database hoarding, the maintenance of shared data consistency and the optimization of logging, which are caused by the weak connectivity and disconnection of wireless networks inherent in mobile database systems under mobile client-server environments. In addition, we proved the superiority of the proposed MQPS by comparing its performance to the C-I-S(Client-Intercept- Server) model.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.1
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• pp.69-80
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• 2005

Recent popularity of web-ready mobile devices such as PDA and cellphone has made mobile Internet access very popular. However, most of existing Web contents and services are optimized for desktop computing environment and not well suited for mobile devices. Considering different system features of mobile devices such as small display and limited input capability, an alternative scheme to access the Web efficiently is required. On the other hand, personalization plays an important role in the tailored access to the Web contents and services. In this paper, we propose a proxy- based personalization scheme of Web service pages for mobile users. For that purpose, in addition to log data. service related features of Web pages are considered for the correct identification of popular services. It automatically provides mobile users with the tailored list of Web services well suited for diverse mobile devices. Consequently, mobile users can utilize customized Web services with minimum navigation on the mobile devices with limited capability. In order to show its effectiveness, we have performed several experiments on the prototype system and reported some of the results.

• The Journal of the Acoustical Society of Korea
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• v.21 no.4
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• pp.407-414
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• 2002

In this paper, we present a method that automatically generates concatenate morpheme based language models to improve the performance of Korean large vocabulary continuous speech recognition. The focus was brought into improvement against recognition errors of monosyllable morphemes that occupy 54% of the training text corpus and more frequently mis-recognized. Knowledge-based method using POS patterns has disadvantages such as the difficulty in making rules and producing many low frequency concatenate morphemes. Proposed method automatically selects morpheme-pairs from training text data based on measures such as frequency, mutual information, and unigram log likelihood. Experiment was performed using 7M-morpheme text corpus and 20K-morpheme lexicon. The frequency measure with constraint on the number of morphemes used for concatenation produces the best result of reducing monosyllables from 54% to 30%, bigram perplexity from 117.9 to 97.3. and MER from 21.3% to 17.6%.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.81-81
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• 2021

가뭄관련 의사결정 시 필요한 정보는 기상 현황 및 전망, 수원현황, 생공·농업 수요현황, 공급계통 등으로서 지자체담당자가 일일이 취득하기에는 번거롭고 어려운 업무라고 할 수 있다. K-water 국가가뭄정보분석센터에서는 이러한 지자체의 업무지원을 위하여 통합 가뭄의사결정 종합상황판을 개발하고 2021년 3월부터 정식오픈하였다. 2019년부터 서비스했던 이전 상황판에서 제공하지 못했던 정보들을 보다 상세하게 제공함으로써 지자체 담당자가 지역에서 발생되는 가뭄을 보다 효율적으로 파악하고 적절한 대응을 하는데 도움이 될 수 있도록 구성하였다. 통합 가뭄의사결정 종합상황판은 국가가뭄정보포털(https://www.drought.go.kr)에 접속하고 GPKI 인증서로 로그인을 하면 접근할 수 있다. 접속한 인증서의 지역을 기준으로 초기 정보가 제공되고 사용자가 선택한 지역을 기준으로 제공되는 정보가 동시에 변경되도록 되어 있어 원하는 지역의 가뭄 관련 정보를 획득하는데 매우 편리하다. 상황판은 다양한 분야의 정보를 요약해서 제공하는 메인화면과 각 분야의 상세 정보를 차트와 통계 형태로 제공하는 3개의 상세화면으로 구성되어 있다. 메인화면에서는 기상현황, 생활 및 공업 현황, 가뭄현황 및 전망, 가뭄대응과 관련된 통계정보와 현황정보를 제공하여 사용자는 해당지역의 가뭄현황을 통합적으로 판단할 수 있다. 특히, 중앙화면에 수원현황, 용수공급체계, 시설현황, 가뭄119정보를 GIS 인터페이스로 제공하여 사용자가 편리하게 속성정보를 획득할 수 있도록 되어 있다. 또한, 4개의 화면에서 제공하는 모든 정보는 Excel 파일로 다운로드하여 활용할 수 있도록 구성하여 담당자가 보고서 등 작성 시 매우 유용하게 활용할 수 있도록 개발하였다. 지자체담당자는 개선된 상황판을 활용함으로써 가뭄관련 업무 시 보다 손쉽게 관련 정보를 획득하고 대응할 수 있을 것으로 예상되며, 이는 가뭄을 실제 담당하는 지자체의 가뭄 대응능력 향상으로 귀결되어 국가적인 가뭄정책 추진 시 많은 도움이 될 것으로 기대된다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.5
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• pp.813-826
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• 2023

Organization members often use the Internet for non-work purposes during work hours, which is called cyberloafing. Certain types of cyberloafing (e.g., webhard, adult, and gambling sites access) can be a major cause of malware infection, which can ultimately generate significant damages to organizations. It therefore is important to examine the relationship between cyberloafing and cybersecurity risks of organizations. We analyzed log data from an internet filtering system of a financial institute and found that the more employees access to blacklist sites, the higher the possibility of malicious code infection. In other words, cyberloafing increases cybersecurity risks of organizations. We suggest that organizations need to monitor and control their members' internet use in an appropriate way.

• Journal of Korean Society of Transportation
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• v.34 no.1
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• pp.1-14
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• 2016

In the recent years, the internet has become accessible without limitation of time and location to anyone with smartphones. It resulted in more convenient travel information access both on the pre-trip and en-route phase. The main objective of this study is to conduct a stationary test for traffic information web/mobile application access indexes from TCS (Toll Collection System); and analyzing the relationship between the web/mobile application access indexes and actual traffic volume on expressways, in order to analyze searching behavior of expressway related travel information. The key findings of this study are as follows: first, the results of ADF-test and PP-test confirm that the web/mobile application access indexes by time periods satisfy stationary conditions even without log or differential transformation. Second, the Pearson correlation test showed that there is a strong and positive correlation between the web/mobile application access indexes and expressway entry and exit traffic volume. In contrast, truck entry traffic volume from TCS has no significant correlation with the web/mobile application access indexes. Third, the time gap relationship between time-series variables (i.e., concurrent, leading and lagging) was analyzed by cross-correlation tests. The results indicated that the mobile application access leads web access, and the number of mobile application execution is concurrent with all web access indexes. Lastly, there was no web/mobile application access indexes leading expressway entry traffic volumes on expressways, and the highest correlation was observed between webpage view/visitor/new visitor/repeat visitor/application execution counts and expressway entry volume with a lag of one hour. It is expected that specific individual travel behavior can be predicted such as route conversion time and ratio if the data are subdivided by time periods and areas and utilizing traffic information users' location.

• Spatial Information Research
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• v.22 no.4
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• pp.67-76
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• 2014

Recently, through the development of IT and mobile technology, spatial information plays a role of infrastructure of the people life and the national economy. Many kinds of applications including SNS and social commerce is to leverage the spatial information for their services. In the case of domestic, spatial open platform that can provide national spatial data infrastructure services in a stable manner has been released. And many people have been interested to the open platform services. However, the open platform currently has many difficulties to analyze its service status and load in real time, because it does not hold a real-time monitoring system. Therefore, we propose a method that can analyze the real-time service status of the open platform using the analysis of the web server log information. In particular, we propose the results of the analysis as follows: amount of data transferred, network bandwidth, number of visitors, hit count, contents usage, and connection path. We think the results presented in this study is insufficient to understand the perfect service status of the open platform. However, it is expected to be utilized as the basic data for understanding of the service status and for system expansion of the open platform, every year.

• Convergence Security Journal
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• v.4 no.2
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• pp.17-25
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• 2004

As Internet and Internet users are rapidly increasing and getting popularized in the world the existing firewall has limitations to detect attacks which exploit vulnerability of web server. And these attacks are increasing. Most of all, intrusions using web application's programming error are occupying for the most part. In this paper, we introduced real-time web-server agent which analyze web-server based log and detect web-based attacks after the analysis of the web-application's vulnerability. We propose the method using real-time agent which remove Process ID(pid) and block out attacker's If if it detects the intrusion through the decision stage after judging attack types and patterns.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.12
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• pp.937-943
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• 2013

Internet Explorer is the popular internet browser the most in domestic. In some version of Internet Explorer, user information could be leaked cause CORS(Cross-Origin Resource Sharing) Internet Explorer support. Different before, without setup a malicious program, attacker can get the user information even account information, credit card usage list and user information with SNS or internet portal site logged in regardless of secure program. Not only Internet Explorer but also mobile browser, it could be. In this paper, we make study of the potential disclosure of user information by attack using CORS, second attack and the way to improvement of vulnerability of CORS.

• Proceedings of the KIEE Conference
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• 2009.04a
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• pp.322-326
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• 2009

본 연구는 지열원식 냉난방 히트펌프 시스템의 상태를 실시간으로 감시하고 열 성능을 실시간으로 평가할 수 있도록 한 지열원식 냉난방 히트펌프 시스템의 상태 감시 및 열 성능 평가 방법에 관한 것으로서, 이러한 본 연구는, 프로그램 실행을 통하여 측정 간격이 설정되고, 다이얼로그 박스 상에서 시스템 개요, 공사개요, 히트펌프설비개요, 지열루핑 설비개요, 버퍼탱크, 건물개요 등을 입력받은 후 시스템의 개통도 이미지 파일프로그램 로딩과 각종 계측기를 통해 전기적인 데이터의 취득 기능 등의 데이터측정 준비를 위한 기본 제1단계와; 취득된 전기적인 데이터를 물리 신호로 변환한 후 기본 데이터 산정하고 결과를 도시하는 "시스템 실시간 작동 상태 감시" 기능의 제2단계와; 기본 순간치 데이터를 근거로 "시스템의 열성능 평가 변수 값 산정과 결과"를 도시하는 제3단계와; 2단계에서의 기본 데이터와 3단계에서의 열성능 평가 변수 값을 후처리용 데이터 파일로 저장하는 제4단계와; 현장에 설치된 지열원식 히트펌프 시스템의 상태를 TCP/IP 프로토콜을 활용하여 원격지(본사)에서 IP 접속을 통하여 원거리 원격 작동상태 감시 기능 및 제어를 수행하는 제5단계를 수행하게 된다.