• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.5
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• pp.1033-1047
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• 2017

Traditional explicit authentication, which requires awareness of the user's authentication process, is a burden on the user, which is one of main reasons why users tend not to employ authentication. In this paper, we try to reduce such cost by employing implicit authentication methods, such as biometrics and location based authentication methods. We define the 4-level security assurance model, where each level is mapped to an explicit authentication method. We implement our model as an Android application, where the implicit authentication methods are touch-stroke dynamics-based, face recognition based, and the location based authentication. From user experiment, we could show that the authentication cost is reduced by 14.9% compared to password authentication-only case and by 21.7% compared to the case where 6-digit PIN authentication is solely used.

• International Journal of Contents
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• v.8 no.3
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• pp.79-82
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• 2012

In digital contents distribution environments, a user authentication is an important security primitive to allow only authenticated user to use right services by checking the validity of membership. For example, in Internet Protocol Television (IPTV) environments, it is required to provide an access control according to the policy of content provider. Remote user authentication and key agreement scheme is used to validate the contents accessibility of a user. We propose a novel user authentication scheme using smart cards providing a secure access to multimedia contents service. Each user is authenticated using a subset of attributes which are issued in the registration phase without revealing individual's identity. Our scheme provides the anonymous authentication and the various permissions according to the combination of attributes which are assigned to each user. In spite of more functionality, the result of performance analysis shows that the computation and communication cost is very low. Using this scheme, the security of contents distribution environments in the client-server model can be significantly improved.

• Journal of the Korean Data and Information Science Society
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• v.27 no.6
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• pp.1557-1564
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• 2016

Recently, an extended warranty of a system following the expiration of the basic warranty is becoming increasingly popular to the user. In this respect, we suggest a two stage maintenance policy under the non-renewing warranty from the user's point of view in this paper. In the first stage, the user has to decide whether or not to purchase the extended warranty period. And, in the second stage, the optimal replacement period following the expiration of the warranty is determined. Under the extended warranty, the failed system is minimally repaired by the manufacturer at no cost to the user. We utilize the expected cost from the user's perspective to determine the optimal two stage maintenance policy. Finally, a few numerical examples are given for illustrative purpose.

• 한국IT서비스학회:학술대회논문집
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• 2003.11a
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• pp.233-240
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• 2003

To develop high-quality software systems satisfying the customer's needs, user-centered design (UCD) process has been emphasized in the area of human-computer interaction. And component-based development (CBD) has been extensively studied to realize a systematic software reuse, thereby reducing the time-to-market and the development cost. Balanced integration of user-centered design process and CBD process will be a promising way for successful software construction, which effectively achieves three goals: the quality of software, the cost of software development, and the time-to-market. However, traditional CBD methodology seems to lack the concept of user-centered design process and the relevant methods. This paper proposes a way of incorporating user-centered design process into a CBD methodology. Firstly, this paper gives the brief introduction of UCD. Secondly, we explain typical UCD activities and methods along the phase of systems development lifecycle and propose the use of usability maturity model (UMM) for integrating UCD activities and methods with those of CBD methodology. Finally, as a case study, we describe the results of comparing the UCD activities to the activities of MaRMI-III, which has been developed as a CBD methodology at ETRI.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.1
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• pp.37-46
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• 2019

In order to present the enhancement direction for the military administrative facilities, that can satisfy the user demands and achieve cost-effectiveness the goal of public projects, this research analyzes the features of functional spaces using Analytical Hierarchy Process(AHP). Basically, the scope is selected to four facilities commander office, private office, public office, and meeting room, because they have an effect on military administrative facilities. Since the space is established by a combination of their own functions, this research begins with an analysis of functional spaces of military administrative facilities, which is verified through literature review and interview with expert. Thereafter, an AHP survey is conducted to military personnel to analyze the priority of functional spaces and to re-classify the functional spaces of each Military administrative facilities. Resultingly, the difference of functional spaces preference according to ranks and facility type are identified. Even though the same military facilities, it means that user satisfaction is different. Therefore, user satisfaction should be considered for each facility at the construction plan. It can minimize overlapped and unused spaces, which can help ensure cost-effectiveness. Consequently, this research suggested the methodology and the process that can take user satisfaction and can support the enhancement of military facilities standards.

• Journal of Advanced Navigation Technology
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• v.15 no.1
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• pp.76-82
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• 2011

Most previous work on network selection in heterogeneous wireless networks has concentrated on the quality of the network alone. Therefore, users are not satisfied with network quality based network selection due to different user preferences. To solve this problem, we proposes a QoE-aware network selection algorithm that is based on the consumption patterns of user preferences which is divided into normal user, cost-sensitive user, quality-sensitive user and video quality as well as network quality. As a result of experiments, cost-sensitive user and quality-sensitive user are satisfied with enhanced QoE by 36% and 3% from the proposed network selection algorithm compared to the normal user, respectively.

• The KIPS Transactions:PartD
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• v.16D no.6
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• pp.945-960
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• 2009

The purpose of this study is to define determinants of VoIP user acceptance and to verify significant causality among latent variables - performance expectancy, effort expectancy, cost expectancy, social influence, facilitating conditions, behavioral intend, use behavior - based on UTAUT model. We presented the expanded hypotheses including the new factor, cost expectancy and analyzed the moderating effect of user age, gender and usage experience variables. For a accuracy of predicted results, we focused on survey analysis with 641 real user samples. Compared to previous studies, it is meaningful that this research verified the conceptual difference between behavioral intention and usage behavior. As a result, all proposed hypotheses accepted and moderating effects are supported significantly in age and use experience moderating variables.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.4
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• pp.130-137
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• 2010

This paper analyzes the main factors affecting user selection of a small-sum electronic payment system using survey data of 396 users. Several findings emerge. First, users consider three pillars and eight factors in adopting a new system : system features(stability, security, and flexibility), transaction cost(payment commission and settlement period), and financial capability of provider(stability of financial structure, risk management capability, and funding capability). Second, the stability of the financial structure of the system provider is the most important factor to user acceptance of a new e-payment system. Users tend to consider uncertainty risk more seriously than transaction cost. This reflects the reality that electronic payment system service industry has not fully fledged yet. Third, some moderating effects exist according to payment methods and business usages. As for payment methods, speedy settlement cycle for wired/wireless phone payment, system stability for credit card and account transfer payment, and security for advance payment means are crucial factors. As for business usages, the stability of financial structure for online game content, system stability for music and video content, proxy payment commission for e-learning content, flexibility of the payment system for digital adult content, and security for public services are decisive ones.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.6
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• pp.675-682
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• 2010

Groundwater is an essential drinking water source in Gyungbuk, South Korea. The primary source of nitrate in groundwater is from nitrogen fertilizers. Efficient management of a small drinking water plant requires a good understanding of its status such as the objective and the cognition of users. The objective of this study is to understand user situation and produce useful user-friendly policy based on user cognition. Most people who participated in this study, should take their groundwater from a good quality source. Even though they would like to have a good facility for getting safe water, they were reluctant to do it due to the cost used. It means that people who drink groundwater have no idea that health safety is affected by groundwater quality. The volume used depended upon personal activities such as agriculture and stockbreeding. We can easily find groundwater with nitrate that exceeds drinking water standards. Therefore, we have to carry out groundwater management with two categories ; 1) drinking water only and 2) others according to objectives in small drinking water systems.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.863-870
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• 2002

The current class scheduling has difficulties in reflecting students' preferences for the classes that they want to take and forecasting the demands of classes. Also, it is usually a repetitive and tedious work to allocate classes to limited time and cesourres Although many research studios in task allocation and meeting scheduling intend to solve similar problems, they have limitations to be directly applied to the class-scheduling problem. In this paper. a class scheduling system using multi agents-based negotiation is suggested. This system consists of student agents, professor agents and negotiation agents each agent arts in accordance with its respective human user's preference and performs the repetitive and tedious process instead of the user The suggested system utilizes negotiation cost concept to derive coalition in the agent's negotiation. The negotiation cost is derived from users' bidding prices on classes, where each biding price represents a user's preference on a selected class. The experiments were performed to verify the negotiation model in the scheduling system. The result of the experiment showed that it could produce a feasible scheduling solution minimizing the negotiation cost and reflecting the users' performance. The performance of the experiments was evaluated by a class success ratio.