• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.695-696
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• 2008

UFC(Ubiquitous Fashionable Computer) is a human oriented fashionable computer with which we exploit the ubiquitous computing environment by our intuitive interface[1]. The multipoint conference in the UFC is expected to be one of the leading applications in the ubiquitous environments. In this paper, we introduce GUI for multipoint conference system in UFC.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.1
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• pp.1-6
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• 2008

The ubiquitous sensor network technique is widely applied to variety of information fields such as home automations, logistics, traffic controls, public administrations, health and environment monitoring and etc. It is particularly useful in the areas where energy consumption is minimal and where continuous monitoring of the surrounding environments, which generates streams of data, are required. In this study, we have designed and implemented a living environment automatic control system which collects the streams of temperature, humidity, light and noise data of a simulated house setting in real-time fashion, then controls the home environment based on the collected data according to the users favorites. In order to differentiate the proposed system from the currently existing similar system, we have demonstrated not only the feasibility of collecting data using sensor network in the controlled environment but also the ability to control the various household equipments through wireless communications.

• Journal of Information Technology Applications and Management
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• v.14 no.2
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• pp.1-10
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• 2007

The ubiquitous computing system is expected to be widely utilized in digital home, logistics control, environment/disaster management, medical/health-care services and other applications. The ubiquitous sensor network (USN) is a key infra-structure of this system. Nodes in the USN are exposed to adverse environments and required to perform their missions with very limited power supply only. Also the sensor network is composed of much more nodes. In case some node consumes up its power capacity under a certain required level, the network topology should change and re-routing/ re-transmission of data is necessitated. Resultantly communication protocols studied for conventional wireless networks or ad-hoc networks are not suitable for the sensor network. Schemes should be devised to control the efficient usage of node power in the sensor network. This paper proposes a routing algorithm to enhance the efficiency of power consumption for USN node and analyzes its performance by simulation.

• KIISE Transactions on Computing Practices
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• v.22 no.8
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• pp.387-392
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• 2016

Context-aware systems require sensor data collecting model and context representing model to provide user-demand services. Sensor data collecting model consists of sensor access information, sensor value, and definition of value types. Context representing model involves certain keywords to symbolize environmental information including the field from sensor data collecting model that is described in markup language such as XML. However, duplicated keywords could be assigned to different contextual information by service developers. As a result, the system may cause misunderstanding and misleading wrong situational information from unintended contextual information. In this paper, we propose a context classification model for collecting appropriate access information and defining the specification of context.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.1
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• pp.66-71
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• 2006

Recently, there are lots of concerning on ubiquitous environment of robots and URC (Ubiquitous Robotic Companion). In this paper, a practical ubiquitous interface system far controlling mobile robots in indoor environments was proposed. The interface system was designed as a manager-agent model including a PC manager, a mobile manager, and robot agents for being able to be accessed by any network. In the system, the PC manager has a 3D virtual environment and shows real images for a human-friendly interface, and share the computation load of the robot such as path planning and managing geographical information. It also contains Hybrid Format Manager(HFM) working for transforming the image, position, and control data and interchanging them between the robots and the managers. Mobile manager working in the minimized computing condition of handsets has a mobile interface environment displaying the real images and the position of the robot and being able to control the robots by pressing keys. Experimental results showed the proposed system was able to control robots rising wired and wireless LAN and mobile Internet.

• Journal of Internet Computing and Services
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• v.6 no.5
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• pp.1-9
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• 2005

In a role based access control through attribute certificate, the use of role assignment certificates and role specification certificates can reduce management cost and the overhead incurred by changing roles, Highly distributed computing environments such as ubiquitous computing environments not having global or broad control. need another attribute certificate management technique, Actually just having role specification certificate separately reduce management cost, But for better performance we structure role specification, We group roles and make the role group relation tree, It results secure and efficient role renewing and distribution, For scalable role specification certificate distribution, the multicasting of packets is used, We take into account the packet lass and quantify performance enhancements of structuring role specification certificates.

• Convergence Security Journal
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• v.5 no.1
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• pp.85-92
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• 2005

For an efficient role based access control in highly distributed computing environment to reduce management cost, we utilize attribute certificates. Especially highly distributed computing environments such as ubiquitous computing environments which cannot have global or broad control, need another attribute certificate management technique. The techniques for transmission of the attribute certificates and management of the group keys should be considered to reduce management cost. For better performance we structure attribute certificates. We group roles and make the role group relation tree. It results secure and efficient role renewing and distribution. For scalable attribute certificate distribution, multicasting packets are used. We take into account the packet loss and quantifying performance enhancements of structuring attribute certificates.

• The KIPS Transactions:PartC
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• v.13C no.6 s.109
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• pp.691-700
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• 2006

To support context-aware services in ubiquitous computing environments, there are required dynamic context managing, context reasoning and context modeling technologies. In previous researches, context services are designed using context ontology used in context aware middleware. So, context service cannot change the context ontology in execution time. In this paper, we propose a hierarchical ontology-based context management model and design a context-aware middleware based on this model for supporting active application adaptability and reflecting users' requirements dynamically in contextual changes. It also provides efficient support for inferencing, interpreting, acquiring and discovering various contexts to build context-aware services and presents a resolution method for context conflict which is occurred in execution of service. As the middleware is implemented on the OSGi framework, it can cause interoperability among devices such as computers, PDAs, home appliances and sensors. It can also support the development and operation of context aware services, which are required in the ubiquitous computing environment.

• Journal of Korea Multimedia Society
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• v.8 no.8
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• pp.1088-1098
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• 2005

Context-Aware is a one of the important researches in ubiquitous computing for providing optimal service to users by acquiring user's intentions and environmental information. Diverse researches are focused on the users and its environment facts for Context-Aware base and introduce a sensing based middleware which engages sever/sensor that operates identifier information to provide services. Context-Aware service which is limited by users and environment facts has the problem of overlapping sensing, unnecessary searching and anonymity of users. Also Server-Centric Context-Aware system requires very high cost to manage and operate the services. On this paper, We introduce Autogenous Context service model to simplify the Context-Aware process and design the middleware which performs decentralize management for Context-Aware information of user's portable devices to minimize problems which is occurred during the management and operation of existing Context-Aware system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.713-718
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• 2011

The advancement of computer network technology, coupled with the growing prevalence of Internet, is promoting ubiquitous computing, also called next-generation computing paradigm, as an important study field that many researches are joining and undergoing. In this paper, as the support technology for creating ubiquitous computer environment, we design the SSDLbased on XMLwhich is used for sending and receiving data by USN application service in a standardized form. A ref model, with no regard to different platforms or implementation languages, is proposed in our research on the basis of web service so that most of unspecified users could apply the standardized protocol designed for sensor data to real sensor data in various application environments based on the designed language. Therefore, through this research we can take advantage of acquisition of USN-based technology and technology draft related to application service.