• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.125-128
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• 2002

In this paper, a new interactive TV service model is proposed. The MPEG-4 system is specified for composing and managing various object streams including user interactions. The data broadcasting model supporting user interactions is designed using MPEG-4 system in our proposal. We evaluate possibility of proposed service model using simulation player. This player supports MPEG-2 TS which contains MPEG-2 video and AC-3 audio streams as a main service and MPEC-4 system data as interactive services as well as user specific EPG information, and XML data, etc as supplemetary services. The player also supports a multi-channel environment. The synchronization between audio and visual data is achieved by DTS and PTS in TS.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.2
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• pp.329-341
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• 2017

A multi-server architecture has been proposed to increase the efficiency of resources due to the rapid growth of computer networks and service providing servers. The smartcard-based authentication protocol in the multi-server environments has been continuously developed through various studies. Recently, Chun-Ta Li et al proposed an authentication protocol that solves Xiong Li el al's authentication protocol vulnerability to user impersonation attack and session key disclosure attack. However, Chun-Ta Li et al's authentication protocol has a problem with user impersonation in the vulnerability analysis and has an unsuitable authentication process. Therefore, this paper proposes a smartcard-based authentication protocol in the multi-server environments that solves the denial of service attack and replay attack vulnerabilities of the authentication protocol proposed by Xiong Li et al.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.820-822
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• 2010

Mobile WiMAX system provides various classes of traffic such as real-time and non-realtime services. These services have different QoS requirements and the QoS aware scheduling has been an important issue. Although many of scheduling algorithms for various services in OFDMA system have been proposed, it is needed to be modified to be applied to Mobile WiMAX system. Since Mobile WiMAX supports five kinds of service classes, it is important to take QoS characteristics of each class into consideration. In this paper, we propose an efficient packet scheduling algorithm to support QoS of each class. Proposed scheme selects a service class first considering QoS Characteristics of each class and choose an appropriate user in the selected class. Simulation results show that the proposed algorithm has better performance than the other algorithm.

• Journal of the Korean Operations Research and Management Science Society
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• v.36 no.4
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• pp.43-61
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• 2011

We first develop a value ecosystem framework to model the SDP(Service Delivery Process) of web services. Since the web service has been evolving from the basic web architecture (e.g., traditional world wide web) to a prosuming platform based on virtualization technologies, the proposed framework of the value ecosystem focuses on capturing the key characteristics of SDP in each type of web services. Even though they share the basic elements such as PP(Platform Provider), CA(Customization Agency) and user group, the SDP in the traditional web services (so-called Web1.0 in this paper) is quite different from the most recent one (so-called Web2.0). In our value ecosystem, users are uniformly distributed over (0, ${\Delta}$), where ${\Delta}$��represents the variety level of users' preference on the web service level. PP and CA provide a standard level of web service(s) and prosuming service package, respectively. CA in Web1.0 presents a standard customization package($s_a$) at flat rate c, whereas PP and CA collaborate and provide customization service with a usage-based scheme. We employ a multi-stage game model to analyze and compare the SDPs in Web1.0 and Web2.0. Our findings through analysis and numerical simulations are as follows. First, the user group is consecutively segmented, and the pattern of the segmentations varies across Web1.0 and Web2.0. The standardized service level s (from PP) is higher in Web1.0, whereas the amount of information created in the value ecosystem is bigger in Web2.0. This indicates the role of CA would be increasingly critical in Web2.0: in particular, for fulfilling the needs of prosuming and service customization.

• Journal of Convergence for Information Technology
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• v.12 no.5
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• pp.150-158
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• 2022

The purpose of this study is to confirm the effectiveness of the evaluation of long-term care insurance visiting care service institutions for the elderly from the user's point of view. To this end, data from a survey of 266 users collected through allocation sampling by region(14 cities and counties) in Jeollabuk-do and public data from 47 institutions were combined and analyzed using a multi-layered model. The main research results are as follows. First, among the five evaluation areas, the higher the score in the 'Rights·Responsibility' area, which is to give users a sense of rights and respect users, the higher the service quality and satisfaction. Second, among the five evaluation areas, the 'Rights·Responsibility' area had an effect on loyalty. In addition, it was found that the 'Outcome' area for satisfaction with institutions and employees and changes in users had an effect on loyalty. Third, it was found that 'Institutional Management', 'Environment·Safety', 'Process' did not affect service quality, satisfaction, and loyalty. Based on these results, it is proposed to reorganize the evaluation scale that users can recognize and that is faithful to the purpose.

• Asia pacific journal of information systems
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• v.14 no.3
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• pp.121-144
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• 2004

Developing a personalized system on a user's behalf which is working around the Internet-based marketplace is one of the challenging issues in intelligent e-business, especially mobile commenrce. It has been highly recommended that such a mobile personalized system has to perceive the user's needs a priori by tracking user's current context such as location with activity and then to identify the current needs dynamically and proactively. Automatically and unobtrusively getting user's context is an inevitable feature for the development of autonomous mobile commenrce. However, personalization methodologies and their feasible architectures for context-aware mobile commerce have been so far very rare. Hence, this paper aims to propose a context-aware mobile commerce development methodology by applying agent and semantic web technologies for personalized reminder system, which is one of the mobile commerce support system. We revisited associationism to understand a buyer's need identification process and adopt the process as 'purchase based on association' to implement a personalized reminder system. Based on this approach, we have showed how the agent-based semantic web service system can be used to realize need-aware reminder system. NAMA(Need-Aware Multi-Agent), a prototype system, has been implemented to show the feasibility of the methodology and framework under mobile setting proposed in this paper. NAMA embeds bluetooth-based location tracking module and identify what a user is currently looking at through her/his mobile device such as PDA. Based on these capabilities, NAMA considers the context, user profile with preferences, and information about currently available services, to aware user's current needs and then link her/him to a set of services, which are implemented as web services.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2004.11a
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• pp.242-248
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• 2004

Personalized reminder systems have to identify the user's current needs dynamically and proactively based on the user's current context. However, need identification methodologies and their feasible architectures for personalized reminder systems have so far been rare. Hence, this paper aims to propose a proactive need identification mechanism by applying agent and semantic web technologies and RFID-based context subsystem for a personalized reminder system, which is one of the supporting systems for a robust ubiquitous service support environment. We have created a prototype system, RFID-based NAMA (Need Aware Multi-Agent), to demonstrate the feasibility of the methodology and of the mobile settings framework that we propose in this paper. NAMA considers the context, user profile with preferences, and information about currently available services, to discover the user's current needs and then link the user to a set of services, which are implemented as web services.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.5
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• pp.74-84
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• 2008

To support advanced collaboration among knowledge workers distributed geographically, there have been extensive researches under the scope of ubiquitous computing environments. Especially, to cope with several known problems in traditional room-based collaboration environments such as uncomfortable sharing of visuals and documents and difficult operation of collaboration tools, several conceptual frameworks are designed and prototyped. Focusing on practical and interactive collaboration with remote nodes, in this paper, we conceptually design an agent-based service composition model for multi-party collaboration environments. The proposed model is designed to automatically discover and combine services to achieve given tasks in a collaboration environment by using high-level user commands (without the knowledge of internal architecture). Based on the service composition model, we develop a multi-agent-based management toolkit for multi-party collaboration environments. It provides easy-to-use GUI to operate various services in an environment and perform service composition algorithm to discover appropriate services and combine them. To explore the possibility of the toolkit we implement collaboration services to support video conference by using the toolkit.

• Journal of information and communication convergence engineering
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• v.2 no.3
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• pp.139-144
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• 2004

In order to transmit various types of multimedia data (i.e. voice, video, and data) over a wireless channel, the coding and modulation scheme needs to be flexible and capable of providing a variable quality of service, data rates, and latency. In this paper, we study a mobile multimedia COMA network combined with the concatenated Reed-Solomon/Rate Compatible Punctured Convolution code (RS/RCPC). Also, this paper propose the combination of concatenated RS/RCPC coder and COMA RAKE receiver for multimedia COMA traffic which can be sent over wireless channels. From the results, using a frequency selective Rayleigh fading channel model, it is shown that concatenated RS/RCPC coder at the wireless physical layer can be effective in providing reliable wireless multimedia CDMA network. And the proposed scheme that combine concatenated RS/RCPC coder and CDMA RAKE receiver provides a significant gain in the BER performance over multi-user interference and multipath frequency selective fading channels.

• The Korean Journal of Food & Health Convergence
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• v.10 no.4
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• pp.9-19
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• 2024

This qualitative study explores the impact of online food delivery platform attributes on customer satisfaction and repurchase intentions. Employing a phenomenological approach, we conducted in-depth interviews and focus group discussions with 15 participants to gain rich insights into user experiences. Thematic analysis revealed key factors influencing satisfaction and loyalty: service quality dimensions (efficiency, reliability, fulfillment, privacy), expectation disconfirmation, perceived usefulness and ease of use, multi-level customer value, relationship quality, electronic word-of-mouth, value co-creation, and phased loyalty formation. Our findings extend customer behavior theory in digital platforms, offering a comprehensive framework for understanding the complex mechanisms underlying user satisfaction and repurchase decisions. The study provides valuable implications for platform operators, highlighting the importance of exceeding customer expectations, enhancing user experience, building trust, leveraging user-generated content, and fostering co-creation processes. Methodologically, we demonstrate the efficacy of qualitative approaches in uncovering nuanced insights in digital service contexts. While acknowledging limitations in generalizability, this research establishes a solid foundation for future investigations into the rapidly evolving domain of online food delivery services. The integrated theoretical approach offers a robust model for analyzing customer behavior in emerging digital service environments, contributing significantly to both academic understanding and practical application in the field of digital service provision and platform management.