• Journal of the Korean Data and Information Science Society
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• v.28 no.1
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• pp.163-171
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• 2017

With the advance of function of smart phone system and internet services, mobile trade grows more popular in the area of e-business or banking. These environmental changes, it makes the needs of authorized certificates. Authorized certificate is not only important in these days but also future society. In 2015, 27 millions of Korean people used public key certificate, but most of them does not know the details on the public key certificate. Therefore, in this paper, we explain and investigate the characteristics on the public certificate and explain the relation ship between authorized certificate and public key encrytion. By investigating several papers, internet data, newspapers and books, we found the historical changes, substantial aspects, the encryption systems on the authorized certificate. Also we study the pros and cons of authorized certificate. Finally we predict the number of issued authorized certificate for the future society based on nonparametric statistical method.

• Journal of Korea Game Society
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• v.11 no.3
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• pp.43-53
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• 2011

The purpose of this study was to enhance the factors of the purchase intention of a mobile game for applying existing. For this study, an exploratory analysis was conducted on 40 ordinary peoples to survey through open-ended questionnaires. After that, the factors was examined by 30 experts. finally, closed-ended survey was conducted to confirm the validity and Reliability Verification. As a result, the factors have been identified with 9. From among these, 2 factors were a Newly derived -The factors of a innovation service and device- Through this study, This research will be useful to provide The basis for extended studies of Marketing, Game-development, Market analysis, etc

• Journal of the Korea Computer Graphics Society
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• v.24 no.4
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• pp.39-54
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• 2018

Recently, augmented reality(AR) based building information applications using a smart phone provide information in the static form irrespective of the distance between a user and a target building. If many target buildings are located close to each other, discrimination of information is reduced due to overlapping information objects. Furthermore, it is difficult to intuitively grasp the current position of the user in the previous AR-based applications. In this paper, to solve these limitations, we have designed and implemented a novel building information system in which the location and size of information objects are adaptively displayed according to locations of a user and target buildings, and which allows users to intuitively understand their location by providing a 3D map that displays the user's location and all target buildings within a given distance in real-time. The AR-based building information application proposed in this paper focuses on the building guide in Deoksu Palace in Jung-gu, Seoul.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1407-1414
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• 2016

In this study, we develop that Location Recommending System using personal emotion information based on Collaborative Filtering. Previous Location Recommending System recommended a place visited by the user of the rating or the pattern of location for the user place. These systems are not high user satisfaction because that dose not consider the user status or have not objectively the information. Using user's personal emotion information to recommend a high-affinity users who have visited the place felt similar emotions objectively can improve user satisfaction with the place. In this study, a user using a mobile application directly register the recognized emotion information using the current position and bio-signal, and using the registered information measuring the similarity of user with a similarity emotion, predicts a preference for the place it is recommended to emotional place. The system consists of a user interface, a database, a recommendation module.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1198-1206
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• 2010

Recently smart phone and tablet PC are regarded as the most valuable mobile devices, so the demand of customers for multimedia supporting has been greatly increased. The network operators are now considering the deployment of relay stations ensuring low installation costs for its service cell to improve the cell capacity. Enhancing the relay stations, however, increases intra-cell interference, which is affecting the quality of service and outage ratio. In this paper, we present MPFR(Multihop Partial Frequency reuse) as the new frequency reuse scheme to increase cell throughput while maintaining low outage ratio for the OFDMA cellular multihop networks. Dynamic power control is also introduced to improve cell capacity. Overall cell throughput and outage ratio are observed by the simulation, and comparison between MPFR and conventional multihop frequency reuse schemes is convincing the performance enhancement.

• Journal of Korea Spatial Information System Society
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• v.12 no.1
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• pp.95-99
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• 2010

Spatial information systems have developed in order to provide users with customized land information in u-City environments. The spatial information systems can detect spatial information for users anytime anywhere. Information which is analyzed by data mining techniques can be offered for other users. Therefore, we propose open map API-based prototype which utilizes frequent pattern mining technique. Proposed prototype can mine interesting trip routes and unknown attractions in location data of geophoto. Also, proposed prototype is the first attempt which analyzes spatial patterns can be represented on a map which is selected by users. Our prototype can be applied to the smart phone like mobile devices.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.3
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• pp.371-378
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• 2016

We have studied on the maritime navigation with functions of navigation route search and maritime safety information for small-size fishery ships, fishing boats, yachts, and boats in coastal seas. We have designed a smart phone application which is more exact information on marine obstacles of islands, aquafarms, and rocks by using land navigation techniques. Our navigation system is relatively easy to be used for costal navigation and may be a substitute for expensive ECDIS(Electronic Chart Display and Information System). Our system consists of maritime navigation databases to manage necessary maritime data and a mobile application to support maritime navigation for operators. We believe that our research findings can improve safety navigation in coastal seas by supporting lower cost, no time-consuming installation and maintenance, and easy-to-use operations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.570-572
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• 2015

NFC (Near Field Communication) is an area of the RFID technology is a kind of short-range wireless communication. NFC technology is to utilize the data transfer, the access control system is usefully employed in many fields, such as mobile payment. Recently smartphone application development using NFC is activated, recognition of the convenience of the current NFC tag is insignificant state. In this paper, it is the content of the Application that was created in order to provide the knowledge of convenience food to the customer to visit the mart. Users with Mart, using smartphones, at a NFC tag that is attached to the food display stand food information, purchasing tips, keeping method, data such efficacy is provided over the screen of the smartphone. If you purchased the food is placed in the refrigerator "moves to the food list of application to click the button, through the food list screen their food list in the refrigerator, and by providing information such as expiration date, the user There is help me to be able to buy the more convenient food.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.145-151
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• 2006

In conjunction with the rapid progress of IT(information technology) an increasing amount of data are being generated. The amount of new data is so big and the type of new data generated from clients or sensor devices needed to be in ubiquitous environment is so various that it is hard to manage and control them. Especially data to be occurred in ubiquitous environment are generated through PDA(personal digital assistant) smart phone, mobile device or sensor units etc. Therefore, to manage and control them generated from ubiquitous devices for decision making, we can use data warehouse as an integrated storage. A data warehouse integrates and aggregates data of several different DBMS into one DBMS. Also the updated data from source data have to be effectively propagated to the data warehouse. Therefore, in this paper, we proposed a mode) for an exact and efficient data management methodology in new IT paradigm environment, ubiquitous computing environment, to apply updated data on the warehouse to make decision. We also show brief result compared to conventional methodology.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.106-115
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• 2014

Until now, because a new product (or facility) launched in market has been retired from one year of age, we can have had ASL by stub-curve method by Iowa curve. Recently, many innovative products with important role in market like display and solar-cell etc. are more durable and, what are better, they have the constant variance in ASL because of their good quality. Of course, there are some ones like smart mobile phone with relatively big dispersion in ASL. Estimating ASL of products like display and solar-cell etc., the new approach is needed. In this paper a new method applied traditional Iowa curve with accelerated reliability test (indoor/outdoor) etc. is proposed.