• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.206-215
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• 2007

Ad-Hoc network technology is a mobile internet technology of the future that will be used widely not only in Mobile Network but also in Wireless Personal Area Network (WPAN) and Ubiquitous Network For this to occur, distributed routing protocol design, loop prevention for link information reduction in overhead for control messages and route restoration algorithm must be improved or complemented. Security techniques that can guarantee safe com-munication between Ad-Hot nodes net also be provided. This study proposes and evaluates a new authentication mechanism for MANET. The mechanism segregates the roles of certification authority to keep with the dynamic mobility of nodes and handle rapid and random topological changes with minimal over-head. That is, this model is characterized by its high expandability that allows the network to perform authentication service without the influence of joining and leaving nodes. The efficiency and security of this concept was evaluated through simulation.

• The Journal of Society for e-Business Studies
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• v.15 no.3
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• pp.99-129
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• 2010

The objective of this research is to identify the factors which influence users' intention to use mobile Internet. There are lots of researches based on Technology Acceptance Model trying to identify the factors which have influence on accepting mobile Internet and its related services. These researches, however, have some limitation in the sense that they focus only on the features of mobile Internet itself while users make overall decision after the comparison of a new service channel with existing service channels in many directions. Therefore, we are going to analyze the impact of users' perception on the difference between mobile and stationary Internet toward their intention to use mobile Internet. We identified the features like ubiquitous availability, context awareness, compatibility, friendliness, and economic value from literature review and developed a structural model about the impact of users' perception on the differences of these features between mobile and stationary Internet toward their intention to use mobile Internet through mediate variables such as perceived ease of use, perceived playfulness, and perceived usefulness. After that, we conducted an experimental analysis for the model, and addressed a solution to rev up the usage of mobile Internet based on the results of the analysis.

• Asia pacific journal of information systems
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• v.24 no.4
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• pp.611-635
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• 2014

Information systems (IS) have become ubiquitous and changed every aspect of how people live their lives. While some IS have been successfully adopted and widely used, others have failed to be adopted and crowded out in spite of remarkable progress in technologies. Both the technology acceptance model (TAM) and the IS Success Model (ISSM), among many others, have contributed to explain the reasons of success as well as failure in IS adoption and usage. While the TAM suggests that intention to use and perceived usefulness lead to actual IS usage, the ISSM indicates that information quality, system quality, and service quality affect IS usage and user satisfaction. Upon literature review, however, we found a significant void in theoretical development and its applications that employ either of the two models, and we raise research questions. First of all, in spite of the causal relationship between intention to use and actual usage, in most previous studies, only intention to use was employed as a dependent variable without overt explaining its relationship with actual usage. Moreover, even in a few studies that employed actual IS usage as a dependent variable, the degree of actual usage was measured based on users' perceptual responses to survey questionnaires. However, the measurement of actual usage based on survey responses might not be 'actual' usage in a strict sense that responders' perception may be distorted due to their selective perceptions or stereotypes. By the same token, the degree of system quality that IS users perceive might not be 'real' quality as well. This study seeks to fill this void by measuring the variables of actual usage and system quality using 'fact' data such as system logs and specifications of users' information and communications technology (ICT) devices. More specifically, we propose an integrated research model that bring together the TAM and the ISSM. The integrated model is composed of both the variables that are to be measured using fact as well as survey data. By employing the integrated model, we expect to reveal the difference between real and perceived degree of system quality, and to investigate the relationship between the perception-based measure of intention to use and the fact-based measure of actual usage. Furthermore, we also aim to add empirical findings on the general research question: what factors influence actual IS usage and how? In order to address the research question and to examine the research model, we selected a mobile campus application (MCA). We collected both fact data and survey data. For fact data, we retrieved them from the system logs such information as menu usage counts, user's device performance, display size, and operating system revision version number. At the same time, we conducted a survey among university students who use an MCA, and collected 180 valid responses. A partial least square (PLS) method was employed to validate our research model. Among nine hypotheses developed, we found five were supported while four were not. In detail, the relationships between (1) perceived system quality and perceived usefulness, (2) perceived system quality and perceived intention to use, (3) perceived usefulness and perceived intention to use, (4) quality of device platform and actual IS usage, and (5) perceived intention to use and actual IS usage were found to be significant. In comparison, the relationships between (1) quality of device platform and perceived system quality, (2) quality of device platform and perceived usefulness, (3) quality of device platform and perceived intention to use, and (4) perceived system quality and actual IS usage were not significant. The results of the study reveal notable differences from those of previous studies. First, although perceived intention to use shows a positive effect on actual IS usage, its explanatory power is very weak ($R^2$=0.064). Second, fact-based system quality (quality of user's device platform) shows a direct impact on actual IS usage without the mediating role of intention to use. Lastly, the relationships between perceived system quality (perception-based system quality) and other constructs show completely different results from those between quality of device platform (fact-based system quality) and other constructs. In the post-hoc analysis, IS users' past behavior was additionally included in the research model to further investigate the cause of such a low explanatory power of actual IS usage. The results show that past IS usage has a strong positive effect on current IS usage while intention to use does not have, implying that IS usage has already become a habitual behavior. This study provides the following several implications. First, we verify that fact-based data (i.e., system logs of real usage records) are more likely to reflect IS users' actual usage than perception-based data. In addition, by identifying the direct impact of quality of device platform on actual IS usage (without any mediating roles of attitude or intention), this study triggers further research on other potential factors that may directly influence actual IS usage. Furthermore, the results of the study provide practical strategic implications that organizations equipped with high-quality systems may directly expect high level of system usage.

• Journal of Intelligence and Information Systems
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• v.13 no.4
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• pp.1-16
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• 2007

According to the expansion of the Internet use and the utilization of e-business, there are an increasing number of studies of intelligent-based systems for the preparation of ubiquitous environment. In addition, expert systems have been developed from Stand Alone types to web-based Client-Server types, which are now used in various Internet environments. In this paper, we investigated the environment of development for web-based expert systems, we classified and analyzed them according to type, and suggested general typical models of web-based expert systems and their architectures. We classified the web-based expert systems with two perspectives. First, we classified them into the Server Oriented model and Client Oriented model based on the Load Balancing aspect between client and server. Second, based on the degree of knowledge and inference-sharing, we classified them into the No Sharing model, Server Sharing model, Client Sharing model and Client-Server Sharing model. By combining them we derived eight types of web-based expert systems. We also analyzed the location problems of Knowledge Bases, Fact Bases, and Inference Engines on the Internet, and analyzed the pros & cons, the technologies, the considerations, and the service types for each model. With the framework proposed from this study, we can develop more efficient expert systems in future environments.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.1
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• pp.1-10
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• 2012

Mobility and quality of service (QoS) are becoming the more important issues in wireless communications. The traditional Internet service is expanding into new access media and applications. Since wireless communication services are accompanied by frequent handovers at remote sites, scalable and fast handover has become a prerequisite for ubiquitous communication. In this paper, the differentiated service (Diffserv) model is deployed in heterogeneous proxy mobile IPv6 (PMIPv6) networks to satisfy the QoS guaranteed service and fast handover requirements. The operational procedures for QoS guaranteed global roaming are presented. In addition, QoS management and handover cost evaluation schemes based on a mobile host's movement scope are proposed. This paper analyzes the reduction in handover delay in a network-based localized mobility management framework. We propose and analyze a PMIPv6 optimized with a global mobile access gateway (G-MAG), which is a network-based entity, to further improve the handover performance in terms of handover delay while maintaining minimal signaling overhead in the air interface among converged heterogeneous wireless networks. The handover signaling procedures with host-based MIPv6 are compared with network-based proxy MIPv6 (PMIPv6) and fast PMIPv6 assisted by G-MAG to show how much handover delay reduction can be achieved. Analytical results show that the handover delay is significantly reduced.

• Journal of KIISE:Information Networking
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• v.35 no.5
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• pp.453-463
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• 2008

The missing child problem is no more a personal problem. It became a social problem that all parents must consider. To this, this study applies USN/RFID technology integrated with GIS for the prevention of missing child. Although RFID is not designed for location sensing, but now it is regarded as a device to facilitate real time location awareness. Such advantages of RFID can be integrated with 4S(GIS/GPS/LBS/GNSS) achieving much synergy effects. In order to prevent kidnapping and missing child, it is necessary to provide a missing child preventing system using a ubiquitous computing system. Therefore, the missing child preventing system has been developed using high-tech such as RFID, GPS network, CCTV, and mobile communication. The effectiveness of the missing child prevention system can be improved through an accurate location tracking technology. This study propose and test a location sensing system using the active RFID tags. This study verifies technical applied service, and presents a system configuration model. Finally, this paper confirms missing child prevention system utilization possibility.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.9
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• pp.369-380
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• 2013

Recently, role-based distributed system models have been proposed to support adaptive interactions in ubiquitous application environment. A Role-based distributed model regards an application as an organization composed of roles, and separate players running role processes from the roles. When an application is running, it binds a role with a player, and the player runs dynamically assigned role processes provided by an application for supporting adaptability. However, there has not been much attention on researches about development and runtime environment for role-based distributed systems. In this paper we suggest an application framework as an environment for developing and executing role-base distributed systems. The application framework is divided into two parts: an organization framework to manage and construct an organization composed of roles necessary in the application, and a player framework to provide running environment for players. In this paper, we focus on the organization framework which supports the creation and management of organizations, directory service for players and allocation of players to roles, and message brokering between roles and players. The proposed framework makes developers to be able to develop highly adaptive distributed systems in the ubiquitous environment.

• The KIPS Transactions:PartC
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• v.14C no.1 s.111
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• pp.95-104
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• 2007

Mobile multimedia services such as TV-call or video streaming are gradually becoming popular in the 3rd or more generation mobile network (IMT-2000). Multimedia traffic is expected to continue increasing into the coming years, and IP technology is considered to be the efficient way of transporting such huge volumes of multimedia traffic. IP-based IMT network platform represents an evolution from IMT-2000. The structure of IP-based IMT network as ubiquitous platform is three-layered model : Middleware including Network Control PlatForm (NCPF) and Service Support PlatForm (SSPF), IP-BackBone (IP-BB), access network including sensor network. Mobility Management (MM) architecture in NCPF is proposed for IP-based IMT network in order to manage routing information and location information separately. The generous existing method of multicast control in IP-based IMT network is Remote Subscription. But Remote Subscription has problem that should be reconstructed whole multicast tree when sender in multicast tree moves to another area. To solve this problem, we propose the way to put Multicast-manager in NCPF.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.733-737
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• 2008

Construction supply chain management focused on materials in construction industry plays a critical role which controls the success and failure of a project. For the efficiency of construction supply chain management, the framework which provides project participants with the information originated from whole construction logistics steps without the omission and discontinuation of information flow is required. The new management framework that can support this environment is necessary because of setting up the complicated and distributed environment including logistics information management by intelligent equipment, co-working management with pre-framework legacy system and various devices(UMPC and PDA etc.) as the information confirmation and electrical transmission tool between the project participants different from former construction supply chain management environment while recently developing ubiquitous technologies such as RFID/USN and intelligent equipment to support logistics process. Therefore, the objective of this study is to introduce the concept of SOA (Service Oriented Architecture) as an alternative of effective information integration under the complex and distributed environment and to propose the SOA-based application model for building intelligent construction supply chain management framework.

• Information Systems Review
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• v.6 no.2
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• pp.79-94
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• 2004

The Internet is now an ubiquitous technology in business and possesses the potential to make the concept of value chain into an attainable reality. We posit that the way the Internet is utilized, the extent of the Internet's impact on business performance, and the extent the firms are prepared to take advantage of the Internet varies from country to country and from industry to industry. Based on data collected from 54 firms in the U.S. and 135 in South Korea, we compared the two countries (U.S. and South Korea) and two major industry groups (manufacturing and service) regarding the pattern of Internet utilization on the Internet from a value chain perspective. The findings show that U.S. companies utilize the Internet more extensively in such areas as human resources management, automation, sales, and advertising than the South Korean counterparts. However, we did not find a statistically significant difference in the way the two countries use the Internet within a value chain model. We also compared Internet practices by industry sector (i.e., service vs. manufacturing) within each country. The results show that firms in the service sector tend to use the Internet more extensively than the manufacturing counterparts in both countries. Particularly in Korea the difference between the sectors was significant in the extent to which they utilized the Internet to support such business activities as inter-organizational alliance, communication, and marketing.