• Journal of KIISE:Computer Systems and Theory
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• v.34 no.5_6
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• pp.214-227
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• 2007

A context-aware service in ubiquitous computing environments aims to supply services according to users' situation information that is dynamically occurring. The existing context-aware workflow systems, such as FollowMe and uFlow, provide context-aware services based on a workflow, which uses users' situation information as transition conditions of a service. But they can't apply users' new service demands, which may dynamically occur even when a workflow is on going, to a workflow scenario. In this paper we propose a context-aware workflow system, which can reapply users' new service demands into an initial workflow without interrupting or deleting the workflow. The proposed system can provide context-aware services without interrupting of service by recognizing exactly a place holder that has to be changed in a workflow scenario and by reconstructing only the changed parts through an incremental parsing method. Therefore, a user can immediately apply his new service demands to an on-going workflow scenario, and he can be guaranteed continuous executions of context-aware services according to a workflow scenario, which includes new service demands.

• The KIPS Transactions:PartB
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• v.14B no.4
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• pp.281-286
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• 2007

This paper proposes an intelligent context awareness middleware(ICAM) for Ubiquitous Computing Environment. In this paper we have researched about the context awareness middleware. The ICAM model is based on ontology that efficiently manages analyses and learns about various context information and can provide intelligent services that satisfy the human requirements. Therefore, various intelligent services will improve user's life environment. We also describe the current implementation of the ICAM for service adaptation based on fuzzy inference that help applications to adapt their ubiquitous computing environments according to rapidly changing. For this, after defining the requirements specifications of ICAM, we have researched the inferred processes for the higher level of context awareness. The Fuzzy Theory has been used in process of inferences, and showed constructing the model through the service process. Also, the proposed fuzzy inferences has been applied to smart Jacky, and after inferring the fuzzy values according to the change of temperature, showed the adaptability of Smart Jacky according to the change of surroundings like temperature as showing the optimal value of status.

• The Journal of Information Systems
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• v.15 no.4
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• pp.73-98
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• 2006

The purpose of this study was to verify and analyze the factors that influence the acceptance intention of u-Commerce users under ubiquitous computing environments. To accomplish this, the Technology Acceptance Model(TAM) of Davis(1989), which has widely been cited in new technologies such as information technology(IT) and information systems(IS) studies was used to develop the research model. First of all, personal characteristics affecting the acceptance intention of u-Commerce were identified as individual variables through literature review. Utilizing the use of the individual variables and the TAM model, the u-Commerce acceptance intention model was established. The research findings indicated that IT acceptance forms and frequencies in IT use did not have a significant impact on perceived usefulness and perceived ease of use of u-Commerce. It was also found that the perceived usefulness proposed in the u-Commerce acceptance model influenced the perceived usefulness. Both ease of use and usefulness were identified to influence attitude for use. Finally, usefulness and attitude for use also positively influenced acceptance intention. The contribution of this study was the examination of the factors affecting acceptance intention of users in u-Commerce and the verification of the usefulness of the TAM model in describing the acceptance of u-Commerce users using structure acceptance model. Furthermore, this study has empirically analyzed how personal characteristics widely used in the study of acceptance of IT can influence the acceptance of u-Commerce.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4B
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• pp.226-234
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• 2005

Context-Aware is the most important facts to reason a personalized and optimized service and to provide it to user. In the previous researches, user and surrounding environment were main facts of Context-Aware and middleware or center server has been proposed to support Context-Aware. In the daily space(for example, home, office, Car, etc), interactions between user and service can be a important facts of Context-Aware. In this paper, Context Autogenesis service model is introduced, simplified the Context-Aware process and designed the middleware which performs decentralize management for Context-Aware information of user's portable devices, so that problems occurred during the management and operation of existing Context-Aware system can be minimized and supporting user anonymity

• The KIPS Transactions:PartA
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• v.17A no.2
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• pp.93-102
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• 2010

There are many complicated situations which could be occurred in users' surroundings, so it is required to develop automation services to provide users with appropriate services in ubiquitous computing environments. However, most of the current context-aware workflow systems express context-aware services only with a single workflow. Therefore, they have difficulties in providing users with various and composite services by combining different workflows. In this paper we propose a CAWL-based context-aware workflow system, where CAWL is a context-aware workflow language to express a composite workflow model by describing individual service workflows. The proposed system can provide users with various composite workflow services based on a service scenario, which is described with CAWL. And by reusing a number of single workflows to construct composite workflow services, it is possible to save time and effort to develop context-aware workflows.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.11
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• pp.861-865
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• 2009

As the hospital environment has been increasingly changed into a ubiquitous environment, the application services for the hospital environment are also faced with new requirements. In particular, the emergence of various mobile devices and the introduction of a wireless sensor network technology have accelerated the realization of the u-healthcare. The multi-agent paradigm has been introduced for satisfying both the integration of information and the various application scenarios established from various environments. This paper describes the software structure and u-applications for u-hospital information system based on ubiquitous environments. And it suggested the construction of a multi agent based distributed framework for supporting u-hospital information system. The suggested framework includes the JADE and distributed object group framework. And it implemented u-application services for supporting doctors and nurses, which provides the patient's health information and ward environment information. Especially, it is using a dynamic security mechanism on the security situation, which has not been emphasized in existing researches, and this paper shows the results for each user through the GUI.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.4
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• pp.115-129
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• 2007

The ubiquitous and autonomic computing environments is open and dynamic providing the universal wireless access through seamless integration of software and system architectures. The ubiquitous computing have to offer the user-centric pervasive services according to the wireless access. Therefore the roaming services with the predefined security associations among all of the mobile devices in various networks is especially complex and difficult. Furthermore, there has been little study of security coordination for realistic autonomic system capable of authenticating users with different kinds of user interfaces, efficient context modeling with user profiles on Smart Cards, and providing pervasive access service by setting roaming agreements with a variety of wireless network operators. This paper proposes a Roaming Coordinator-based security management framework that supports the capability of interoperator roaming with the pervasive security services among the push service based network domains. Compared to traditional mobile systems in which a Universal Subscriber Identity Module(USIM) is dedicated to one service domain only, our proposed system with Roaming Coordinator is more open, secure, and easy to update for security services throughout the different network domains such as public wireless local area networks(PWLANs), 3G cellular networks and wireless metropolitan area networks(WMANs).

• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.783-798
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• 2004

An e-business client application in ubiquitous mobile computing environment may become disconnected from the enterprise server due to broken communication connections caused by the limitation of mobile computing environments(limited battery life of the mobile device, low bandwidth communication, incomplete wireless communication infrastructure, etc). It Is even Possible that mobile client application Intentionally operates in disconnected mode to reduce communication cost and the power consumption of the mobile device. We use “data hoarding” as a means of providing local autonomy to allow transactions to be processed and committed on the mobile host despite of disconnection. The key problem to this approach is the synchronization problem that serialize potentially conflicting updates from disconnected clients on master objects of the server database. In this paper, we present a new transaction synchronizing method that splits a transaction into a set of independent component transactions and give the synchronization priority on each component taking the possibility of use and conflicts in the server into consideration. Synchronization is performed component by component based un synchronization priority. After the Preferred component of a no bile transaction succeeds in synchronization with the server, the mobile transaction can pre-commit at server. A pre-committed transaction's updated value is made visible at server before the final commit of the transaction. The synchronization of the component with low synchronization priority can be delayed in adaption to wireless bandwidth and computing resources. As a result, the availability of important data updated by mobile client is increased and it can maximize the utilization of the limited wireless bandwidth and computing resources.

• 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.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.433-438
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• 2014

The demanding in construction of the stand-alone networks and interconnection between convergence devices have led an increase in research on MANET and the application of MANET has been paid much attention as a Ubiquitous computing which is growing fast in the field of computer science. With performance both as hosts and routers, easy network configuration, and fast response, mobile nodes participating in MANET are suitable for Embedded computing but have vulnerable points, about lack of dynamic network topology due to mobility, network scalability, passive attacks, and active attacks which make it impossible to manage continuous security authentication service. In this study, proposes S-EKE authentication mechanism for a robust authentication based on MANET and through identify wireless environment security vulnerabilities, currently being used in OTP S/Key and DH-EKE analyzes.