• Journal of Digital Convergence
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• v.12 no.2
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• pp.243-248
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• 2014

The demand for messenger service goes on growing rapidly with widespread use of smartphones. Generally, the smartphone messenger provides group communication functions in which users can make the group and communicate with each other. In the mobile meeting, the attendees can participate in the meeting with use of smartphone messengers wherever they are. To make the mobile meeting put to practical use, the mobility and privacy should be ensured to attendees. To satisfy the mobility requirement, the user which is not belong to the group members should not be able to participate in the meeting. To ensure the privacy requirement, the attendees should have not to repudiate the meeting results. In this study, the mobile meeting authentication scheme is proposed which provides mobility and privacy. The proposed scheme consists of meeting group creation, group key generation, group signature and verification protocols. All attendees should have to participate in the signature verification because it is based on the challenge-response type protocol. Thus, it's not possible to collude with malicious attendees to change the meeting results.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.2
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• pp.373-381
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• 2017

Currently, various types of user authentication methods based on public certificates are used in domestic financial transactions. Such an authorized certificate method has a problem that a different security module must be installed every time a user connects an individual financial company to a web server. Also, the financial company relying on this authentication method has a problem that a new security module should be additionally installed for each financial institution whenever a next generation authentication method such as biometric authentication is newly introduced. In order to solve these problems, we propose an integrated authentication system that handles user authentication on behalf of each financial institution in financial transactions, and proposes an integrated authentication protocol that handles secure user authentication between user and financial company web server. The new authentication protocol is a modified version of OAuth2.0 that increases security and efficiency. It is characterized by performing a challenge-response protocol with a pre-shared secret key between the authentication server and the financial company web server. This gives users a convenient and secure Single Sign-On (SSO) effect.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.10-19
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• 2014

Despite the movement of safe traffic by the Korean government to reduce deaths in traffic accidents, the casualties increase year by year. In particular, more and more accidents and casualties are reported from car collisions from the back of the vehicles parked for managing traffic accidents on the road, cleaning main roads and medial strips, repairing roads. In order to response to these accidents, the government should take protective measures for road users. In the last decade, seventy-one cases have been reported to occur during highway repair and maintenance. As a result, eight persons were killed and seventy-six were injured, showing the high death rate of 11.3 percent. Therefore, it seems urgent to take some actions against it. The United States and European countries legislate that vehicles of road repair and maintenance should be mandatorily equipped with shock absorber at the back. Korea, however, does not have such legislative measures, which are needed at this time to protect workers on the road. This study compares the performance of the traditional shock absorber for road maintenance vehicles with that of the rear safety guard using air bag, manufactured in accordance with related laws in Korea. Based on the results of the 60km/h rear collision test, this paper proposes improvements in related laws and regulations in an attempt to reduce casualties.

• Archives of design research
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• v.14 no.3
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• pp.127-134
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• 2001

This study suggests a model of experimental visual artworks with interactive art forms in which 2-D paintings are transformed to interactive 3-D animation works. Multimedia programming was employed to evolve objective still paintings to the animation of computer 3-D images with respect to visual ideas derived from visual components in the still painting and to response to the reactions users. The format and technique of the art works are based upon the contents developed by the author and the research materials are selected from the surrealistic paintings of tile world-famous Belgian painter, Rene Magritte. In the present paper, following topics are discussed in detail: a study of various visual cases occurring in transforming still paintings to animation works containing interactive components; a study of 3-D imaging and image processing techniques to transform 2-D paintings to 3-D images; animation techniques for interaction and overall structuring techniques; multimedia programming and user interface.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.9
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• pp.2285-2301
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• 2012

Peer-to-Peer (P2P) networks are becoming more and more popular in video content delivery services, such as Video on Demand (VoD). Scalability feature of P2P allows a higher number of simultaneous users at a given server load and bandwidth to use stream service. However, the quality of service (QoS) in these networks is difficult to be guaranteed because of the free-riding problem that nodes download the recourses while never uploading recourses, which degrades the performance of P2P VoD networks. In this paper, a distributed trust model is designed to reduce node's free-riding phenomenon in P2P VoD networks. In this model, the P2P network is abstracted to be a super node hierarchical structure to monitor the reputation of nodes. In order to calculate the reputation of nodes, the Hidden Markov Model (HMM) is introduced in this paper. Besides, a distinction algorithm is proposed to distinguish the free-riders and malicious nodes. The free-riders are the nodes which have a low frequency to free-ride. And the malicious nodes have a high frequency to free-ride. The distinction algorithm takes different measures to response to the request of these two kinds of free-riders. The simulation results demonstrate that this proposed trust model can improve QoS effectively in P2P VoD networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5231-5248
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• 2016

As a service-oriented paradigm, web service composition has obtained great attention from both academia and industry, especially in the area of cloud service. Nowadays more and more web services providing the same function but different in QoS are available in cloud, so an important mission of service composition strategy is to select the optimal composition solution according to QoS. Furthermore, the selected composition solution should satisfy the service level agreement (SLA) which defines users' request for the performance of composite service, such as price and response time. A composite service is feasible only if its QoS satisfies user's request. In order to obtain composite service with the optimal QoS and avoid SLA violations simultaneously, in this paper we first propose a QoS evaluation method which takes the SLA satisfaction into account. Then we design a service selection algorithm based on our QoS evaluation method. At last, we put forward a parallel running strategy for the proposed selection algorithm. The simulation results show that our approach outperforms existing approaches in terms of solutions' optimality and feasibility. Through our running strategy, the computation time can be reduced to a large extent.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.187-192
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• 2001

High-Rise Building Construction Project which has high uncertainty and complexity, causes lots of problems under construction. In particular, the integration between design phase and construction phase highly affects a construction project in terms of cost and time. To possibly make the flexible response and preliminary verification against the construction planning problems in high rise building project, this paper proposes the Engineering-Construction Management System based on 4D CAD that put the time factor together with 3D CAD. The usefulness of this system has been verified through the actual project. It could helps the reducing trials and errors during construction phase by catching the factors on problems of project. Ultimately it will allow users to save project cost and duration by field application.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.573-579
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• 2017

The game industry using Smart phones and related market is rapidly growing every year and a graphical view of the game fun and games player is in a diverse environment improvement. Game visuals in the design of the application of the user's perspective, very simple tricks, unlike such as the game's environment is pc, but more sophisticated and to improve the quality of the game, planning is required. Ranking the top rankings, game downloads this study, therefore, has recently structured questionnaire based on the case in existing research conducted a survey. The surveyed more than 200 million people downloaded the Onmyoji game users in China was limited to the preferences of each gui survey analyzed. Preference shown in graphic identify success factors should be improved to lighting of the basic elements of design / ux ui and applications should be taken into account when designing the game. A Study on Design Factors for research purposes. The results verification the importance of visual elements, information elements, manipulation, and rapid response.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.4 no.1
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• pp.43-51
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• 2010

In this paper, we developed a digital Taekwondo trainer system based on the electronic protector was authorized by the World Taekwondo Federation for the improvement of user's training effects and athletic performances. Our system consists of E-Kick Bag with sensors for sensing hits, taekwondo trainer program and receiver for interconnection of E-kick Bag to program. Taekwondo trainer system also has an advantage to improve training effects and athletic performances such as hit-accuracy and reaction velocity by appointing a hitting target for users with 6 LED indicators. The taekwondo trainer program is a user interface to provide training courses such as progress training of response time and stamina, preparation training for real sparring by training scenario. It has also characteristics which are to strengthen and supplement user's pros and cons by analyzing hitting intensity and accuracy from training. In this paper, we implemented a test targeting eight taekwondo players on the playing list include a member of the Korea national team and conducted a survey in order to evaluate the utility of our system.

• Journal of the Korea Society of Computer and Information
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• v.13 no.2
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• pp.41-50
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• 2008

This paper proposes the recommendation system which is a new method using RFM method in mobile internet environment. Using a implict method which is not used user's profile for rating, is not used complicated query processing of the request and the response for rating, it is necessary for user to keep the RFM score about users and items based on the whole purchased data in order to recommend the items. As there are some problems which didn't exactly recommend the items with high purchasablity for new customer and new item that do not have the purchase history data. in existing recommendation systems, this proposing system is possible to solve existing problems, and also this system can avoid the duplicated recommendation by the cross comparison with the purchase history data. It can be improved and evaluated according to the criteria of logicality through the experiment with dataset, collected in a cosmetic cyber shopping mall. Finally, it is able to realize the personalized recommendation system with high purchasablity for one to one web marketing through the mobile internet.