• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2001.10a
• /
• pp.50-54
• /
• 2001

Information systems development entails planning, analysis, design and construction phases. The analysis phase identifying user requirements is the most important of these phases. Since unidentified defects in the early phase causes increased work and costs as development proceeds, the quality of analysis results affects the quality of the resultant system. Major tasks in the analysis phase are data modeling and process modeling. Research on building a knowledge-based system for data modeling have been conducted much, however, not sufficiently for process modeling. As a system environment with high user interaction increases, research on process modeling methods and knowledge- based systems considering such environment are required. In this research, a process modeling framework for information systems with high user interaction is suggested and a knowledge-based system for supporting the suggested framework is implemented. A proposed model consists of the following tasks: event analysis, process analysis, and event/process interaction analysis. Event analysis identifies business events and their responses. Process analysis break down the processes of an enterprise into progressively increasing details. Decomposition begins at the function level and ends when the elementary process level is reached. Event/process interaction analysis verifies the results of process analysis and event analysis. A knowledge-based system for supporting a proposed process modeling framework is implemented in a web-based environment.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2006.11a
• /
• pp.288-300
• /
• 2006

In this paper, we consider a channel ordering problem that seeks to minimize the total interference in mobile radio networks. If a base station receives connection request from a mobile user, one of the empty channels that are fixed to the base station is assigned to the mobile user. Among several channels available, we can choose one that seems to make least interference with other channels assigned to adjacent base stations. However, a pair of channels that are not separated enough do not generate interference if both of them are not simultaneously used by mobile users. That is, interference between channels may vary depending on the channel assignment sequence for each base station and on the distribution of mobile users. To find a channel assignment sequence that seems to generate minimum interference, we develop an optimization model considering various scenarios of mobile user distribution. Simulation results show that channel assignment sequence determined by the scenario based optimization model significantly reduces the interference provided that scenarios and interference costs are properly generated.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.29 no.5
• /
• pp.19-25
• /
• 2015

The management of energy resources for efficient utilization of the energy resources while reducing the system costs is a critical technical issue. Among many kinds of the energy resource management, the energy reduction for indoor lighting systems is getting much concern as a large portion of energy consumption has been made for indoor lightings. In this paper, an energy-efficient lighting control scheme for indoor lighting systems in order to reduce the energy consumption by controlling the luminous flux and the lighting direction under the illuminance constraints is proposed. With the use of the user location information for the luminaire which is closely located to the user, the proposed scheme firstly sets the light direction of the luminaire to be aligned to the user location. Then, an optimization problem to find the luminous flux of each luminaire is formulated in order to minimize the luminous flux sum of the luminaires with the constraints for the dynamic ragne of the luminous flux, and the light flux for each luminaire is determined by the solution of the problem. Simulation results show that the proposed scheme outperforms the luminaire control scheme with only the luminous flux control in the evaluation of satisfaction of the required illuminance level.

• Journal of Korean Society of Transportation
• /
• v.30 no.4
• /
• pp.71-81
• /
• 2012

The Korean government has actively accepted private investments in building expressways to improve its financial status. As of 2012, 422km of 9 private expressways are under operation, and until 2016 additional 15 are planned to be built with private investments. However, on average, each private expressway is at most 37km long, which works against economies of scale in maintenance and thus leads to inefficiencies such as traffic jams, driver inconveniences, and the increase in operating costs. To resolve these problems, the present study suggested that the maintenance and tolling system should be unified across each private operator. Unifying the operation of private expressways was expected to reduce user travel times and tolls, and save operator maintenance costs. These economic effects were expected to be tantamount to hundreds of billions of dollars. The shared toll collecting system will also reduce user's delays by removing main line tollgates. This can save another hundreds of billions of dollars by ensuring driver's convenience and safety.

• The Journal of the Korea Contents Association
• /
• v.11 no.1
• /
• pp.92-101
• /
• 2011

However, in order to create a stereoscopic 3D image, independently, it is required to spend expensive manufacturing costs and to have special techniques. As 3D display devices have been generalized, there is an increasing need for implementing a stereoscopic 3D image without a burden of expensive costs. This paper proposes some methods to implement stereoscopic 3D images easily by utilizing a marker tracking technology using a single camera. In addition, the study made it possible for the resolution of an image to be adjustable dynamically. This paper will be committed to the promotion of the field of UCC (User Created Contents) using stereoscopic 3D images by attracting the active participation of general users in the field of the implementation of stereoscopic 3D images.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.1
• /
• pp.166-183
• /
• 2013

It requires a lot of costs and manpower to manage an election. The electronic voting scheme can make the election system economic and trustful. The widespread use of smart phones causes mobile voting to be a major issue. The smart phone can be used as a mobile voting platform since it can carry out many services in addition to basic telephone service. To make mobile voting practical and trustful, we analyzed two subjects of study. Firstly, the way to make a biometric based mobile ID, which has legal binding forces. In mobile voting, user identification is accomplished on line since the voter should be able to vote wherever they go. The digital ID conducts a similar role to the need for a resident card. The user's identity is bound to the resident card legally. To bind the user's identity to the smart phone, we use USIM. Biometric recognition is also needed to authenticate the user, since the user cannot prove him or her on line face-to-face. The proposed mobile ID can be reissued by means of introducing a random secret value. Secondly, the mobile voting scheme is proposed where candidates can accept election results without doubt. The goal of an election is to select a leader among two or more candidates. Existing electronic voting schemes mainly focus on the study of ballot verification accomplished by voters. These approaches are not safe against collusion attacks where candidates and the election administration center are able to collude to fabricate election results. Therefore, a new type of voting and counting method is needed where candidates can directly take part in voting and counting stages. The biometric based multi-signature scheme is used to make the undeniable multi-signed ballot. The ballot cannot be verified without the help of all candidates. If candidates accept election results without a doubt, the fairness of the election is satisfied.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.46 no.1
• /
• pp.46-55
• /
• 2009

We study the problem of searching documents containing each of several keywords (conjunctive keyword search) over encrypted documents. A conjunctive keyword search protocol consists of three entities: a data supplier, a storage system such as database, and a user of storage system. A data supplier uploads encrypted documents on a storage system, and then a user of the storage system searches documents containing each of several keywords. Recently, many schemes on conjunctive keyword search have been suggested in various settings. However, the schemes require high computation cost for the data supplier or user storage. Moreover, up to now, their securities have been proved in the random oracle model. In this paper, we propose efficient conjunctive keyword search schemes over encrypted documents, for which security is proved without using random oracles. The storage of a user and the computational and communication costs of a data supplier in the proposed schemes are constant. The security of the scheme relies only on the hardness of the Decisional Bilinear Diffie-Hellman (DBDH) problem.

• Journal of Internet Computing and Services
• /
• v.20 no.6
• /
• pp.119-127
• /
• 2019

This paper proposes a new authentication model to solve the problem of personal information takeover and personal information theft by service providers using centralized servers for user authentication and management of personal information. The centralization issue is resolved by providing user authentication and information storage space through a decentralize platform, blockchain, and ensuring confidentiality of information through user-specific symmetric key encryption. The proposed model was implemented using the public-blockchain Ethereum and the web-based wallet extension MetaMask, and users access the Ethereum main network through the MetaMask on their browser and store their encrypted personal information in the Smart Contract. In the future, users will provide their personal information to the service provider through their Ethereum Account for the use of the new service, which will provide user authentication and personal information without subscription or a new authentication process. Service providers can reduce the costs of storing personal information and separate authentication methods, and prevent problems caused by personal information leakage.

• Informatization Policy
• /
• v.21 no.1
• /
• pp.77-98
• /
• 2014

The Korean government has been promoting the establishment of comprehensive information systems as one of supports for preschools' administration. This support is expected to enhance the efficiency of preschool education support systems and to improve the quality of educational services. The gap between government's expectation on an introduction of the information system and preschool educators' expectations has also been an issue in deploying this new system. This study identifies user resistance factors for comprehensive preschool administration assistance systems' deployment. We find that the performance expectancy, social influence, effort expectancy, and the psychological cost of user resistance have impacts on the user resistance. When these factors related resistance are resolved in the process of systems' deployment, active participation in these systems by preschool educators would be increased.

• The KIPS Transactions:PartD
• /
• v.14D no.5
• /
• pp.545-554
• /
• 2007

The user authentication and authorization in the current home network system almost works at home and home users, sometimes novice, should manage the system directly. This situation can make much of troubles, sometimes cause some suity problems. Moreover, the system costs high to build up, demands special user knowledge to maintain. In this paper, we propose the user authentication and authorization system based on remote management server to solve the problems, designed and implemented the system. To verify the system performance and function, we built a demo system for information appliances. The results of the test, the authentication and authorization function works well and reliably.