• Proceedings of the Korea Information Processing Society Conference
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• 2001.04b
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• pp.727-730
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• 2001

초고속 인터넷 서비스의 확대에 따라 이를 교육에 직 간접적으로 응용하기 위한 노력이 지속적으로 진행되어 왔다. 특히 웹 기반의 가상강의 저작도구를 통한 웹 코스웨어는 원거리 학습자들의 학습 욕구를 자기 주도적인 학습을 통해 가능케 했고 기존의 텍스트, 사운드를 통한 가상강의에서 동영상이 가미된 주문형 교육 서비스(EOD: Education On Demand)가 가능해졌다. 그러나 이를 이용하는 학습자는 전체적인 모듈의 이해를 통해 수업이 진행됨에 따라 학습과정에서는 질의응답을 튜터를 통해 웹 캐스팅이 이루어졌다. 따라서, 질의응답은 텍스트 형식의 E-mail, 채팅, 게시판, 방명록을 통해 이루어지므로 학습자가 요구한 질의 내용을 잘못 이해하고 튜터가 학습 과정에서의 피드백을 제공하지 못함으로써 개인 학습의 동기부여가 감소됨에 따라 흥미를 잃게 되었다. 본 논문에서는 이러한 문제점을 개선하기 위해 멀티 캐스팅 기법을 통해 교육용 서버를 이용한 학습지원도구를 분석, 설계한다. 가상강의는 기본적인 컨텐츠를 제시하고 그를 통해 수업이 진행되는 과정에서의 질의응답을 일대다(One-To-Many)의 멀티 캐스팅 서비스를 튜터가 지정한 교육용 서버를 통해 텍스트 형식이 아닌 강의자료로 쓰인 문서 파일에 직접 작성하여 전송하게 된다. 따라서 튜터는 메일링 서비스를 통해 질문사항을 자신의 폴더 서비스로 확인하고 즉시 학습자에게 피드백을 제공함으로써 튜터와 학습자들간의 커뮤니케이션이 활발히 이루어지며, 상호작용의 증가를 통해 웹 기반의 컨퍼런싱(WBC: Web Based Conferencing)을 가질 수 있게 된다.rver는 Client가 요청한 Content(services)를 전달 해 주는 컨텐트 전달 모듈(Content Deliver Module)과 서버 Phonebook 엑세스 모들(Server Phonebook Access Module)로 구성되어 있다.외 보다 높았다(I/O ratio 2.5). BTEX의 상대적 함량도 실내가 실외보다 높아 실내에도 발생원이 있음을 암시하고 있다. 자료 분석결과 유치원 실내의 벤젠은 실외로부터 유입되고 있었고, 톨루엔, 에틸벤젠, 크실렌은 실외뿐 아니라 실내에서도 발생하고 있었다. 정량한 8개 화합물 각각과 총 휘발성 유기화합물의 스피어만 상관계수는 벤젠을 제외하고는 모두 유의하였다. 이중 톨루엔과 크실렌은 총 휘발성 유기화합물과 좋은 상관성 (톨루엔 0.76, 크실렌, 0.87)을 나타내었다. 이 연구는 톨루엔과 크실렌이 총 휘발성 유기화합물의 좋은 지표를 사용될 있고, 톨루엔, 에틸벤젠, 크실렌 등 많은 휘발성 유기화합물의 발생원은 실외뿐 아니라 실내에도 있음을 나타내고 있다.>10)의 $[^{18}F]F_2$를 얻었다. 결론: $^{18}O(p,n)^{18}F$ 핵반응을 이용하여 친전자성 방사성동위원소 $[^{18}F]F_2$를 생산하였다. 표적 챔버는 알루미늄으로 제작하였으며 본 연구에서 연구된 $[^{18}F]F_2$가스는 친핵성 치환반응으로 방사성동위원소를 도입하기 어려운 다양한 방사성의 약품개발에 유용하게 이용될 수 있을 것이다.었으나 움직임 보정 후 영상을 이용하여 비교한 경우, 결합능 변화

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.8
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• pp.1588-1596
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• 2015

In the Internet of Things (IoT), resource-constrained devices such as sensors are capable of communicating and exchanging data over the Internet. The IETF standard group has specified an application protocol CoAP, which uses UDP as a transport protocol, allows such a lightweight device to transmit data. Also, the IETF recommended the DTLS binding for securing CoAP. However, additional features should be added to the DTLS protocol to resolve several problems such as packet loss, reordering, fragmentation and replay attack. Consequently, performance of DTLS is worse than TLS. It is highly required for lightweight devices powered by small battery to design and implement a security protocol in an energy efficient manner. This paper thus discusses about DTLS performance in the perspective of energy consumption. To analyze the performance, we implemented IEEE 802.15.4 based test network consisting of constrained sensor devices in the Cooja simulator. We measured energy consumptions required for each of DTLS client and server in the test network. This paper compares the energy consumption and amount of transmitted data of each flight of DTLS handshake, and the processing and receiving time. We present the analyzed results with regard to code size, cipher primitive and fragmentation as well.

• Journal of Korea Spatial Information System Society
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• v.2 no.2 s.4
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• pp.25-37
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• 2000

As computer systems of high capacity and high performance recently emerged, various researches about GISs(Geographic Information Systems) have been in progress and many GIS applications have also been developed. From the domestic situation where many people are using mobile devices, because of the recent advances in the mobile technology, we can infer that the time will come when every individual will carry a mobile device with a GPS(Global Positioning System) module resulting from the development of a miniature GPS Module. Therefore, a mobile GIS that can allows users to deal with dynamic GIS data management and perform their tasks while moving will be required. This paper discusses the design and implementation of a mobile GIS using the shareware DBMS, called postgresSQL. The Mobile GIS in which a mobile concept is utilized at the GIS data server makes it possible to insert, delete, update GIS data, to zoom in and zoom out displayed maps, and to locate the user's position on the client device. Therefore, It is possible to manage dynamic GIS data in order to deal with GIS data on the maps while moving, connect various GIS data servers through the middleware, and connected with ITS (Intelligent Transport System) which is one of applications of the Mobile GIS developed in this paper.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.14-23
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• 2014

Existing attending management systems require a high cost and are lack of convenience. In this paper, we propose a convenient and practical attending management system as follows: First, our system allows us to construct an attendance book in an easy and simple way. A professor does not have to provide the information of students using the small screen of his smartphone. Instead, each student manages his own information via the app designed for a student in our system. Then the professor can construct the attendance book using another app designed for the professor by confirming the requests from the app designed for a student. Second, our system enables a professor to utilize the pictures of students as well as other information of students to have a good relationship with students. Third, our system provides a functionality of checking attendance automatically by calling the names of students via the app designed for the professor. Then the professor has only to match the name with the face of each student. Fourth, our system provides a functionality of checking attendance in a very fast manner. Our system can complete this behavior within a short time since all students can join the attendance simultaneously by using the app designed for the student. Fifth, our system can prevent an illegal attendance easily by utilizing the distance information.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.2
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• pp.47-62
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• 2016

An integrated database(DB) system was developed to manage the marine geological data and geophysical data acquired from around the Korean peninsula from 2009 to 2013. Geological data such as size analysis data, columnar section images, X-ray images, heavy metal data, and organic carbon data of sediment samples, were collected in the form of text files, excel files, PDF files and image files. Geophysical data such as seismic data, magnetic data, and gravity data were gathered in the form of SEG-Y binary files, image files and text files. We collected scientific data from research projects funded by the Ministry of Oceans and Fisheries, data produced by domestic marine organizations, and public data provided by foreign organizations. All the collected data were validated manually and stored in the archive DB according to data processing procedures. A geographic information system was developed to manage the spatial information and provide data effectively using the map interface. Geographic information system(GIS) software was used to import the position data from text files, manipulate spatial data, and produce shape files. A GIS DB was set up using the Oracle database system and ArcGIS spatial data engine. A client/server GIS application was developed to support data search, data provision, and visualization of scientific data. It provided complex search functions and on-the-fly visualization using ChartFX and specially developed programs. The system is currently being maintained and newly collected data is added to the DB system every year.

• The Journal of Society for e-Business Studies
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• v.22 no.2
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• pp.169-185
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• 2017

Juliano Rizzo and Thai Duong, the authors of the BEAST attack [11, 12] on SSL, have proposed a new attack named CRIME [13] which is Compression Ratio Info-leak Made Easy. The CRIME exploits how data compression and encryption interact to discover secret information about the underlying encrypted data. Repeating this method allows an attacker to eventually decrypt the data and recover HTTP session cookies. This security weakness targets in SPDY and SSL/TLS compression. The attack becomes effective because the attacker is enable to choose different input data and observe the length of the encrypted data that comes out. Since Transport Layer Security (TLS) ensures integrity of data transmitted between two parties (server and client) and provides strong authentication for both parties, in the last few years, it has a wide range of attacks on SSL/TLS which have exploited various features in the TLS mechanism. In this paper, we will discuss about the CRIME and other versions of SSL/TLS attacks along with countermeasures, implementations. We also present direction for SSL/TLS attacks resistance in practice.

• Spatial Information Research
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• v.12 no.2
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• pp.165-179
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• 2004

With the spread of wireless internet, the interest in mobile applications and services is increasing. Korea Wireless Internet Standardization Forum has been establishing the standards for mobile platform and map service in the wireless internet environment. This study aims to present a paragon of mapping middleware that plays the role of broker for wireless internet map service: in particular, it focuses on the interoperability with generic map servers. In this study, we developed a method for applying current map servers to the wireless internet map service, and analyzed the request/response structure of the map servers which have different operation characteristics in order to allow our middleware to fully utilize the functionalities of the map servers. The middleware we developed is composed of .NET-based XML Web Services: it has a lightweight module for image map and a map representation module for choropleth map, symbol map, chart map, etc. This mapping middleware is a broker between mobile client and generic map server, and supports .NET clients and Java clients as well. Its component-based interoperability grants the extensibility for the wireless internet dedicated map servers of the future in addition to the current generic map servers.

• Journal of the Korea Society of Computer and Information
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• v.16 no.7
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• pp.137-148
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• 2011

Different from the traditional client-server model, it is possible for participants in a cooperative distributed system to get quality services regardless of the number of participants in the system since they voluntarily pool or share their resources in order to achieve their common goal. However, some selfish participants try to avoid providing their resources while still enjoying the benefits offered by the system, which is termed free-riding. The results of free-riding in cooperative distributed systems lead to system collapse because the system capacity (per participant) decreases as the number of free-riders increases, widely known as the tragedy of commons. As a consequence, designing an efficient incentive mechanism to prevent free-riding is mandatory for a successful cooperative distributed system. Because of the importance of incentive mechanisms in cooperative distributed system, a myriad of incentives mechanisms have been proposed without a standard for performance evaluation. This paper draws general incentive design considerations which can be used as performance metrics through an extensive survey on this literature, providing future researchers with guidelines for the effective incentive design in cooperative distributed systems.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.133-138
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• 2006

Electronic Navigational Charts(ENCs) are official nautical charts which are equivalent to paper charts with supplementary information. Although their main purpose is to be used for the safe navigation of ships, they also contain much information on coasts and seas which may be interesting to ordinary people. However, there is no easy way to access them because of therir specialized data format, access method and visualization. This paper proposes on implementation of SVG for the access and services of ENCs. SVG(Scalable Vector Graphic) makes it possible to make use of Vector graphics for servicing maps in basic internet browsing environment. Implement of SVG for ENC applications by this research is free of special server side GIS mapping system and client side extra technology. The implementation of SVG for ENC Applications can be summarized as follows: Firstly, SVG provides spatial information to possess searching engine to embody SVG map. Secondly, SVG can provide high-quality vector map graphics and interactive facility without special Internet GIS system. It makes it possible to use services with very low cost. Thirdly, SVG information service targeting on maritime transportation can be used as template, so it can be used dynamically any other purpose such as traffic management and vessel monitoring. Many good characteristics of SVG in mapping at computer screen and reusability of SVG document provide new era of visualization of marine geographic information.

• Korean Journal of Digital Imaging in Medicine
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• v.13 no.1
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• pp.13-20
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• 2011

Now a days in our society, occupation boundaries have become blurred, and come into the limelight in the prior occupation or miss about new workplace. Medical area is no exception also, So we face urgent problem about protecting and spreading RT work-sphere simultaneously. This research allow to identify on RT role area of digital environment that is obscure profession-realm specially, and open up a new field hereafter. We examined present RT role area of digital environment in the more than thirty medical facility(general or university hospital) through questionnaire/visit survey from PACS administrator. Survey sentence comprises total 29 sentence over all main quadrisection-(eX. hospital formation & treatment state and PACS team composition & organization and PACS team workplace and PACS team daily workload), We performed comparative analysis in general contents perspectively. further more, divided main 5 section based on upper analysis and then manufactured output in consideration of each medical facility's operation state. There are comparative problem of hospital policy, So we maintained information security of each facility exhaustively. First, we separated a survey output into main 5 section as follows-(eX. PACS server & maintenance manage, Client/interlock manage, PACS data conversion, 3D reconstruction, PACS data im/export)-that received by 35 medical facility. And then manufactured output with comparative analysis about RT role area each section, general IT managing team about medical environment was out of existence that fill up with RT manpower in the surveyed medical facility consequently. What is worse, hospitals that entirely fill up with another worker were 3 place amazingly. Our specific statistic results show, the respondents was 63% that agree with reorganization of formation base on independence team, and supplement of the personnel average -continuous with upper agreement simply-was about 2.64. Further more, if reorganization break out with only RT manpower, quota TO will increase by geometric progression. Protecting and spreading role workplace is much accounted of the our inevitable project surely and more than 95% PACS administrator's have confidence in this proposition unconditionally. Henceforth, look forward to meeting the RT vision of many-sided multiplayer, based on acquire a specialized IT knowledge actively and open up a new work-field with frontier spirit.