• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.5
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• pp.394-400
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• 2013

WoT (Web of Things) was proposed to realize intelligent thing to thing communications using WEB standard technology. It is difficult to adapt security protocols suited for existing Internet communications into WoT directly because WoT includes LLN(Low-power, Lossy Network) and resource constrained sensor devices. Recently, IETF standard group propose to use DTLS protocol for supporting security services in WoT environments. However, DTLS protocol is not an efficient solution for supporting end to end security in WoT since it introduces complex handshaking procedures and high communication overheads. We, therefore, divide WoT environment into two areas- one is DTLS enabled area and the other is an area using lightweight security scheme in order to improve them. Then we propose a mutual authentication scheme and a session key distribution scheme for the second area. The proposed system utilizes a smart device as a mobile gateway and WoT proxy. In the proposed authentication scheme, we modify the ISO 9798 standard to reduce both communication overhead and computing time of cryptographic primitives. In addition, our scheme is able to defend against replay attacks, spoofing attacks, select plaintext/ciphertext attacks, and DoS attacks, etc.

• Cartoon and Animation Studies
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• s.46
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• pp.181-206
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• 2017

In the near future, we are expected to live in a Mixed Reality environment where reality and virtuality coexist as today we live using the Internet and smartphones in our daily lives. The relevant content based on the idea of Mixed Reality crystallizing is currently expanding, and it is time for research on it. This study examines the current situation and the development direction of mixed reality contents. Typical mixed reality contents can be classify by wearability. We analyzed HoloLens, a mixed reality wearable device that is worn on a head, which is a example of wearable device. As an example of unwearable device, we also analyzed the Room2Room which is a communication system that combines video with augmented reality-based telepresence avatar. Mixed Reality content will develop in the direction of implementing expanded use of information and more natural realism through the interactive combination of Reality, Virtual Reality, and Augmented Reality. As head-mounted wearable technology develops, Mixed Reality content is expected to become popular by increasing the number of Mixed Reality device users if convenience and price competitiveness are secured. The way of unifying Mixed Reality wearable devices must be established in order to increase convenience, and the environment based on Mixed Reality will be created through diversifying leisure activity content. Telepresence Avatar is expected to develop into Mobile Hologram Avar as Mixed Reality content accessible anywhere and at anytime beyond space limits. Another potential for development of Telepresence Avatar is the combination of Avatar moving on user's thought, Augmented Human technology and Mixed Reality.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.169-185
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• 2017

Given that nowadays things get very fast due to the pervasive use of the Internet and mobile devices, decision-making time can be an important variable in the online economic decisions. Although in experimental and behavioral economics, measures like scores or earnings are usually preferred, this study argues that the time variable can be dealt with as a new decision outcome. Thus, by selecting some psychological factors presumably impactful in the online context (i.e., incidental emotions, psychological distances, and individual's impulsivity), this study tested their effect on decision time in the online centipede game. As a result, the mean decision time in the game was longer (1) in the happiness condition than in the anger condition and (2) in the friend condition than in the stranger condition. The people with attention difficulties spent a short time in the decision and the people who dislike complex problems spent a short time in explaining their decision. This study can contribute to the field as it used the decision time as the dependent variable and it tested the effect of psychological factors in the context of online decision-making. Future studies can be conducted in other online decision situations or by considering other psychological variables.

• The Journal of Society for e-Business Studies
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• v.16 no.4
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• pp.197-220
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• 2011

The smartphone is simply beyond the means of communication equipment, to line up the turning point of mobile convergence, is recognized as a service tool of new concept the camera, game, multimedia function, digital multimedia broadcasting, mobile internet etc, that use of smartphone is working toward developed a variety and new business models. The study is empirically studied casualties that self-determination influences flow and satisfaction which is intrinsic motivation of smartphone. There are many studies on flow, is intrinsic motivation, influencing satisfaction and Loyalty, but there are little studies which variables influences flow. this study is explore causality of autonomy, competence, relatedness which are major variables of self-determination theory that studied factors effecting intrinsic motivation influencing flow and satisfaction. This study developed a research model to explain the use of smartphone, and collected 670 survey responses from the office workers of seoul S company who had experiences with such smartphone. To prove the validity of the proposed research model, SEM analysis is applied with valid 670 questionnaires. The results, firstly, autonomy positively influences flow. secondly, competence significantly influences flow. thirdly, relatedness significantly influenced flow. also, upper above results shows that flow influences satisfaction.

• Journal of Korea Game Society
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• v.11 no.6
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• pp.127-138
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• 2011

The creation and interchange of information through the Internet network forms online community and makes Social Network Game (SNG) as a new entertainment by grafting it onto the most popular online games. SNG means the service which amalgamates social network service (e.g., Facebook, Twitter, etc) strong points and the fun of online game. It promotes the intimacy of relation between the friends above social network service and the gaming amusement for users. The domestic SNG market is currently fast changing according to the smart environment which is quickly shifted. The existing online game field will continuously maintain a market size. SNOG will be more developed because it is competitive from the business perspective of managing cost and production cost when compares with the existing online game. In relation to Facebook, Twitter, etc. overseas SNS platform base SNOG service, the domestic competition for launching SNG is expected to heat up as NHN, Daum and SK Communication introduce open type SNS. This study examines the successful factors and strategy for domestic SNOG by studying the case of MapleStory Adventures successful possibility. The possible successful factors are combing SNS on the existing popular online game, marketing through the existing users, and solving the platform problem of a failure factor of NexonStar. This case study is expected to contribute to the domestic SNOG industry development by providing several implications for the successful factors and strategy of SNOG which will be continuously developed.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.5
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• pp.722-727
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• 2010

This paper is presented to study simplification of face image using cubic spline interpolation for a business card with 2D barcode. People often forget business card's owner because business cards don't be included a face picture generally. To solve such problem, many applications have be developed through mobile devices, Internet and so on. But they couldn't caught up with value of existing business card mad by paper. Hence, some methods which can put information on business card using 1D or 2D barcode had suggested. but they couldn't include information like face image or company logo image which have too much data. Therefore, we study the simplification method of face image to encode from a face image to 2D barcode. The simplification method using spline curves defined by feature points which we dotted on face, ears, hair, eyebrows, nose, lips, neck, etc.. on a face area. for experiment, we see real face image and simplified face image made by proposed method after we automatically extract face watch through camera. In experimental results, data of simplified face image was reduced as small as it can be expressed by 2D barcode, and confirmed that it can effectively express features.

• The Journal of Information Systems
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• v.24 no.1
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• pp.95-117
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• 2015

With the active smartphones user exceeding 500 million by the end of 2014, China has now become the largest smartphone market in the world. Smartphone companies provide variety of information through a range of applications, such as communications, entertainment, games, and so on. There were many studies conducted about the user acceptance and continuous intention of mobile service. However, it is still not quite clear what factors attract people to reuse smartphone in China. This paper examines the continuous intention of smartphone about Chinese customers. This study incorporates perceived enjoyment as a additional construct into a extended TAM model, by integrating a hedonic service of smartphone. We propose a research model that reflects the individual characteristics and usage contexts of smartphone, such as innovativeness, social influence, and service quality, and analyze the structural relationship between the main variables through empirical study. This study empirically investigated a research model and conducted a survey of smartphone service users in China. Our study proved that perceived enjoyment has a positive influence on continuous intention to use smartphone services. This paper provides the managers an insight that smartphone companies should take more consideration on how to provide more enjoyable service and attract customers to reuse their services.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.2
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• pp.164-171
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• 2006

Recently Digital multimedia broadcasting (DMB) has been available as a commercial service. The users sometimes have difficulty in finding their preferred multimedia contents and need to spend a lot of searching time finding them. They are even very likely to miss their preferred contents while searching for them. In order to solve the problem, we need a method for recommendation users preferred only minimum information. We propose an algorithm and a system for recommending users' preferred contents using preference transition probability from user's usage history. The system includes four agents: a client manager agent, a monitoring agent, a learning agent, and a recommendation agent. The client manager agent interacts and coordinates with the other modules, the monitoring agent gathers usage data for analyzing the user's preference of the contents, the learning agent cleans the gathered usage data and modeling with state transition matrix over time, and the recommendation agent recommends the user's preferred contents by analyzing the cleaned usage data. In the recommendation agent, we developed the recommendation algorithm using a user's preference transition probability for the contents. The prototype of the proposed system is designed and implemented on the WIPI(Wireless Internet Platform for Interoperability). The experimental results show that the recommendation algorithm using a user's preference transition probability can provide better performances than a conventional method.

• Journal of KIISE:Information Networking
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• v.30 no.1
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• pp.75-81
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• 2003

User authentication, including confidentiality, integrity over untrusted networks, is an important part of security for systems that allow remote access. Using human-memorable Password for remote user authentication is not easy due to the low entropy of the password, which constrained by the memory of the user. This paper presents a new password authentication and key agreement protocol suitable for authenticating users and exchanging keys over an insecure channel. The new protocol resists the dictionary attack and offers perfect forward secrecy, which means that revealing the password to an attacher does not help him obtain the session keys of past sessions against future compromises. Additionally user passwords are stored in a form that is not plaintext-equivalent to the password itself, so an attacker who captures the password database cannot use it directly to compromise security and gain immediate access to the server. It does not have to resort to a PKI or trusted third party such as a key server or arbitrator So no keys and certificates stored on the users computer. Further desirable properties are to minimize setup time by keeping the number of flows and the computation time. This is very useful in application which secure password authentication is required such as home banking through web, SSL, SET, IPSEC, telnet, ftp, and user mobile situation.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1529-1532
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• 2003

최근 인터넷과 모바일 시스템이 급속히 발달함에 따라 이를 통하여 지리정보와 같은 공간데이터를 제공하는 서비스가 증가하였다. 이는 대용량 데이터에 대한 관리 및 빠른 처리와 급증하는 사용자에 대한 높은 동시처리량 및 높은 안정성을 요구하였고, 이를 해결하기 위하여 비공유 공간 데이터베이스 클러스터가 개발되었다. 비공유 공간 데이터베이스 클러스터는 고가용성을 위한 구조로서 문제가 발생할 경우 다른 백업노드가 대신하여 서비스를 지속시킨다. 그러나 기존의 비공유 공간 데이터베이스 클러스터는 클러스터 구성에 대한 회복을 위하여 로그를 계속 유지하므로 로그를 남기기 위해 보통의 질의처리 성능이 저하되었으며 로그 유지를 위한 비용이 증가하였다. 또한 노드단위의 로그를 갖기 때문에 클러스터 구성에 대한 회복이 직렬적으로 이루어져 고가용성을 위한 빠른 회복이 불가능 하였다. 따라서 본 논문에서는 비공유 공간 데이터베이스 클러스터에서 고가용성을 위한 병렬 회복 기법을 제안한다. 이를 위해 클러스터 구성에 대한 회복을 위한 클러스터 로그를 정의한다. 정의된 클러스터 로그는 마스터 테이블이 존재하는 노드에서 그룹내 다른 노드가 정지된 것을 감지할 때 남기기 시작한다. 정지된 노드는 자체회복을 마친 후 클러스터 구성에 대한 회복을 하는 단계에서 존재하는 복제본 테이블 각각에 대한 클러스터 로그를 병렬적으로 받아 회복을 한다. 따라서 정지된 노드가 발생할 경우에만 클러스터 로그를 남기므로 보통의 질의처리의 성능 저하가 없고 클러스터 로그 유지 비용이 적으며, 클러스터 구성에 대한 회복시 테이블단위의 병렬적인 회복으로 대용량 데이터인 공간데이터에 대해 빠르게 회복할 수 있어 가용성을 향상시킨다.들을 문법으로 작성하였으며, PGS를 통해 생성된 어휘 정보를 가지고 스캐너를 구성하였으며, 파싱테이블을 가지고 파서를 설계하였다. 파서의 출력으로 AST가 생성되면 번역기는 AST를 탐색하면서 의미적으로 동등한 MSIL 코드를 생성하도록 시스템을 컴파일러 기법을 이용하여 모듈별로 구성하였다.적용하였다.n rate compared with conventional face recognition algorithms. 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 변화가 선조체 영역에서 국한되어 나타나며 그 유의성이 움직임 보정 전에 비하여 낮음을 알 수 있었다. 결론: 뇌활성화 과제 수행시에 동반되는