• The KIPS Transactions:PartC
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• v.12C no.7 s.103
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• pp.949-958
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• 2005

In the paper we study key agreement schemes when a party needs to establish a session key with each of several parties, thus having multiple session keys. This situation can be represented by a graph, tailed a key graph, where a vertex represents a party and an edge represents a relation between two parties sharing a session key. graphs to establish all session keys corresponding to all edges in a key graph simultaneously in a single session. A key agreement protocol of a key graph is a natural extension of a two-party key agreement protocol. We propose a new key exchange model for key graphs which is an extension of a two-party key exchange model. using the so-called randomness re-use technique which re-uses random values to make session keys for different sessions, we suggest two efficient key agreement protocols for key graphs based on the decisional Diffie-Hellman assumption, and prove their securities in the key exchange model of key graphs. Our first scheme requires only a single round and provides key independence. Our second scheme requires two rounds and provides forward secrecy. Both are proven secure In the standard model. The suggested protocols are the first pairwise key agreement protocols and more efficient than a simple scheme which uses a two-party key exchange for each necessary key. Suppose that a user makes a session key with n other users, respectively. The simple scheme's computational cost and the length of the transmitted messages are increased by a factor of n. The suggested protocols's computational cost also depends on n, but the length of the transmitted messages are constant.

• The KIPS Transactions:PartB
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• v.11B no.3
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• pp.369-380
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• 2004

In this paper, we propose a web page weighting scheme based on WordNet-based collaborative evaluation and hyperlink to improve the precision of web search engine. Generally search engines use keyword matching to decide web page ranking. In the information retrieval from huge data such as the Web, simple word comparison cannot distinguish important documents because there exist too many documents with similar relevancy. In this paper, we implement a WordNet-based user interface that helps to distinguish different senses of query word, and constructed a search engine in which the implicit evaluations by multiple users are reflected in ranking by accumulating the number of clicks. In accumulating click counts, they are stored separately according to lenses, so that more accurate search is possible. Weighting of each web page by using collaborative evaluation and hyperlink is reflected in ranking. The experimental results with several keywords show that the precision of proposed system is improved compared to conventional search engines.

• Convergence Security Journal
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• v.14 no.7
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• pp.3-8
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• 2014

Recently, A utilization request of the U-Healthcare services are increasing rapidly. This is because the increase in smartphone users and ubiquitous computing technology was developed. Furthermore, the demand for access to and use of medical information systems is growing rapidly with a smartphone. This system have the advantage such as they can access from anywhere and anytime in the healthcare information system using their smartphone quickly and easily. But this system have various problems that are a privacy issue, the location disclosure issue, and the potential infringement of personal information. this problems are arise very explosive. Therefore, we propose a secure information security system that can solve the security problems in healthcare information systems for healthcare workers using smartphone. Our proposed system, doctors record, store, modify and manage patient medical information and this system would be safer than the existing healthcare information systems. The proposed system allows the doctor to perform further authentication by transmitting using SMS to GOTP message when they accessing medical information systems. So our proposed system can support to more secure system that can protect user individual information stealing and modify attack by two-factor authentication scheme. And this system can support confidentiality, integrity, location information blocking, personal information steal prevent using cryptography algorithm that is easy and fast.

• Spatial Information Research
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• v.15 no.2
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• pp.111-121
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• 2007

The GPS positioning offer 3D position using code and carrier phase measurements, but the user can obtain the precise accuracy positioning using carrier phase in Real Time Kinematic(RTK). The main problem, which RTK have to overcome, is the necessary to have a reference station(RS) when using RTK should be generally no more than 10km on average, which is significantly different from DGPS, where distances to RS can exceed several hundred kilometers. The accuracy of today's RTK is limited by the distance dependent errors from orbit, ionosphere and troposphere as well as station dependent influences like multipath and antenna phase center variations. For these reasons, the author proposes Network based GPS Carrier Phase Differential Positioning using Multiple RS which is detached from user receiver about 30km. An important part of the proposed system is algorithm and software development, named DAUNet. The main process is corrections computation, corrections interpolation and searching for the integer ambiguity. Corrections computation of satellite by satellite and epoch by epoch at each reference station are calculated by a Functional model and Stochastic model based on a linear combination algorithm and corrections interpolation at user receiver are used by area correction parameters. As results, the users can obtain the cm-level positioning.

• Journal of Digital Convergence
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• v.13 no.4
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• pp.227-233
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• 2015

The recent health care is growing rapidly want to receive offers users a variety of medical services, can be exploited easily exposed to a third party information on the role of the patient's hospital staff (doctors, nurses, pharmacists, etc.) depending on the patient clearly may have to be classified. In this paper, in order to ensure safe use by third parties in the health care environment, classify the attributes of patient information and patient privacy protection technique using hierarchical multi-property rights proposed to classify information according to the role of patient hospital officials The. Hospital patients and to prevent the proposed method is represented by a mathematical model, the information (the data consumer, time, sensor, an object, duty, and the delegation circumstances, and so on) the privacy attribute of a patient from being exploited illegally patient information from a third party the prevention of the leakage of the privacy information of the patient in synchronization with the attribute information between the parties.

• Convergence Security Journal
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• v.15 no.1
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• pp.37-47
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• 2015

This study aims at exploring effects of airport special guard's security service value on customers' satisfaction and customers' loyalty. Users of airport facilities located in Incheon were selected as the population in Jun. 2013 and the sample was extracted using cluster random sampling and 460 people were used for a final analysis. The questionnaire used for the study was composed of total 22 items including 6 items of socio-demographical characteristics, 6 items of security service value, 6 items of customers' satisfaction and 4 items of customers' loyalty etc. and using SPSSWIN 18.0, factor analysis, reliability analysis, multiple regression analysis, path analysis etc. were used. The credibility of the questionnaire was indicated to be over ${\alpha}$=.809. The findings are as follows. First, security service value has an effect on customers' satisfaction. if monetary value is enhanced, satisfaction with service composition is high. second, security service value has an effect on customers' loyalty. If monetary value and time value are enhanced, will of continuous use and will of recommendation of others are high. Third, customers' satisfaction has an effect on customers' loyalty. If satisfaction with service composition and satisfaction with use decision are increased, will of continuous use and will of recommendation of others are high. Fourth, airport special guard's security service value has a direct and indirect effect on customers' satisfaction and customers' loyalty. That is, it means customers' satisfaction is an important variable to mediate security service value and customers' loyalty.

• Journal of Korea Game Society
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• v.9 no.6
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• pp.45-56
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• 2009

This Study has limited our scope to the study of satisfaction factor. Due to the extensiveness of fun factors of games. We had identified satisfaction factors through investigating various theories based on funology. Then, we have directly applied the satisfaction factors to games in order to define the satisfaction factors of online FPS game. Then, we have applied the satisfaction factors on to four online games, at the first phase of the study. We interviewed a group of online FPS game experts to identify the constituent elements of the factors and concluded the second phase of our investigation based on the results from the first and second phases, we have conducted a survey to verify the hypothesis. We have verified the reciprocal relationship between the satisfaction factors and game popularity by conducting a multiple regression analysis on the survey results. To conclude, there is a correlation between online FPS games and the satisfaction factors; the satisfaction factors cause the users to be absorbed into the game and to enjoy it for a long period of time.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.10
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• pp.4335-4338
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• 2015

Background: Oral cancer is the third most common malignancy in Saudi Arabia, the highest incidence of which is reported from Jazan province. The objective of this study was to evaluate the association of various locally used substances, especially shamma, with oral cancer in the Jazan region of Saudi Arabia. Materials and Methods: A hospital-based case-control study was designed and patient records were scanned for histologically confirmed oral cancer cases. Forty eight patients who were recently diagnosed with oral cancer were selected as cases. Two healthy controls were selected for each observed case and they were matched with age (+/- 5 years) gender and location. Use of different forms of tobacco such as cigarettes, pipe-smoking and shamma (smokeless-tobacco) was assessed. Khat, a commonly used chewing substance in the community was also included. Descriptive analysis was first performed followed by multiple logistic regression (with and without interaction) to derive odds ratios (ORs) and 95% confidence interval (CIs). Results: Mean age of the study sample (56% males and 44% females) was 65.3 years. Multinomial regression analysis revealed that shamma use increased the odds of developing oral cancer by 29 times (OR=29.3; 10.3-83.1). Cigarette (OR=6.74; 2.18-20.8) was also seen to have an effect. With the interaction model the odds ratio increased significantly for shamma users (OR=37.2; 12.3-113.2) and cigarette smokers (OR=10.5; 2.88-3.11). Khat was observed to have negative effect on the disease occurrence when used along with shamma (OR=0.01; 0.00 - 0.65). Conclusions: We conclude that shamma, a moist form of smokeless tobacco is a major threat for oral cancer occurrence in the Jazan region of Saudi Arabia. This study gives a direction to conduct further longitudinal studies in the region with increased sample size representing the population in order to provide more substantial evidence.

• Journal of Korea Multimedia Society
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• v.7 no.1
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• pp.132-144
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• 2004

With the rapid development of internet technology, the number of internet users and the amount of multimedia information on the internet is ever increasing. Recently, the web sites, such as e-business sites and shopping mall sites, deal with lots of image information. As a result, it is required to support content- based image retrieval efficiently on such image data. This paper proposes an intelligent image retrieval system, which adopts XML, technology. To support object-based col)tent retrieval on product catalog images containing multiple objects, we describe a multi -level metadata structure which represents the local features, global features, and semantics of image data. To enable semantic-based and content-based retrieval on such image data, we design a XML-Schema for the proposed metadata and show how to represent such metadata using XML- documents. We also describe how to automatically transform the retrieval results into the forms suitable for the various user environments, such as web browser or mobile browser, using XSLT The proposed scheme can be easily implemented on any commercial platforms supporting XML technology. It can be utilized to enable efficient image metadata sharing between systems, and it will contribute in improving the retrieval correctness and the user's satisfaction on content-based e-catalog image retrieval.

• Journal of Broadcast Engineering
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• v.25 no.1
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• pp.94-104
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• 2020

Currently media consumption over fixed/mobile Internet is mostly conducted by adaptive media streaming technology such as DASH (Dynamic Adaptive Streaming over HTTP), which is an ISO/IEC MPEG (Moving Picture Experts Group) standard, or some other technologies similar to DASH. All these heavily depend on the HTTP caches that ISPs (Internet Service Providers) are obliged to provide sufficiently to make sure fast enough Web services. As a result, as the number of media streaming users increases, ISPs' burden for HTTP cache has been greatly increased rather than CDN (Content Delivery Network) providers' server burden. Hence ISPs charge traffic cost to CDN providers to compensate for the increased cost of HTTP caches. Recently in order to reduce the traffic cost of CDN providers, P2P (Peer-to-Peer)-assisted DASH system was proposed and a peer selection algorithm that maximally reduces CDN provides' traffic cost was investigated for this system. This algorithm, however, tends to concentrate the burden upon the selected peer. This paper proposes a new peer selection algorithm that distributes the burden among multiple peers while maintaining the proper reduction level of the CDN providers' cost. Through implementation of the new algorithm in a Web-based media streaming system using WebRTC (Web Real-Time Communication) standard APIs, it demonstrates its effectiveness with experimental results.