• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6C
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• pp.611-618
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• 2009

Recently, an indoor location-aware technology has been focused on as a key technology for context awareness in ubiquitous computing environments. The conventional Cricket system was designed with a non-centralized architecture, which has advantages in terms of user privacy, deployment, scalability, decentralized administration, network heterogeneity, and low cost. In this paper, an indoor location system based on TDOA between RF and ultrasound signals is designed, which improves the Cricket system. A 2.4GHz frequency is employed for transmitting RF messages, which is in an ISM band. The beaconing frequency is doubled to enhance the channel utilization rate. The ultrasonic pulse duration is optimized to increase the coverage of ultrasonic signals. The function of calculating location coordinates is embedded in a listener. The location-update rate and location accuracy are also improved.

• Journal of Information Technology Applications and Management
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• v.12 no.3
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• pp.97-109
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• 2005

The internet and wireless communication technologies are creating ubiquitous environments in which various services are expected anytime and anywhere. Many hardware facilities have been developed and system structures are suggested for mobile services to realize a ubiquitous computing environment with appropriate quality. But these applications are not designed in the consideration of the general capabilities to perform user's wireless and mobile communication/transaction. Consequently, different needs from users are not sufficiently satisfied yet. In this study, we suggest structure of the emerging network system for mobile commerce that provides users with seamless and ubiquitous environments using location information which exploit context-aware technology.

• 전자공학회논문지 IE
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• v.43 no.1
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• pp.67-72
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• 2006

According to the growth of wireless networks, and the spread of mobile devices, the provision of recommender services to help consumers find items to purchase with the use of the suited contexts is an important issue in mobile commerce. In this paper, we propose a proactive mobile commerce service that enables a consumer to obtain relevant information efficiently by using differentiated recommendation in context-aware environment. This paper describes the recommendation method and presents grocery shopping application prototype that implement the method. Several experiments are performed and the results verify that the proposed method's recommendation performance is better than other existing methods.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.177-178
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• 2006

The real-time tracking system is an essential factor for the development of low cost sensor networks for use in pervasive computing and ubiquitous networking. In this paper, we address the interference problems of the sensor network platform with ultrasonic for location tracking system. Ubiquitous indoor environments often contain substantial amounts of metal and other such reflective materials that affect the propagation of radio frequency signals in non-trivial ways, causing severe multi-path effects, dead-spots, noise, and interference. Especially we present a novel reducing interference location system that is particularly well suited to support context-aware computing. The system called Pharos, aims to combine the advantages of real-time tracking systems that implement distributed environment with regardless of infrastructure or infrastructure-less wireless sensor networks.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.5-10
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• 2004

In this paper, we propose a service control framework and user interface in a class automation of ubiquitous computing environment. We propose UPnP-based service control architecture and introduce an example service scenarios for automatic classroom. We present context-aware design approaches to argument user interface. We also present intelligent content authoring that facilitates producing e-learning content using activity context.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.579-582
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• 2009

With the aid of the increasing interests of Context-aware Augmented Reality Agent (AR Agent), various researches of AR Agent have been performed to explore the possibility of the agent as novel interface and the entity responding autonomously by user's input. However, in previous works, AR Agents are lack of specific method for using various contextual information. To revolve around those problems, we propose the Behavior Generation System for Context-aware AR Agent using layered architecture. Based on Belief-Desire-Intention (BDI) model and Hierarchical Task Network (HTN) searching, the sequence of agent behavior has been selected in behavior planning layer. Then, the agent evaluates appropriateness of behaviors using previous behavior and the type of input before activation. This behavior generation system can be applied for edutainment, game, and assistant agent, which need intuitive and effective behaviors to convey information. Through this research, we expect that the Context-aware AR Agent could support for not only information delivery, but also the capability of effective communication for user.

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.633-642
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• 2004

A self-adaptation with context-awareness is needed within network to meet costumed services according a user's changing constraints. But the existing network has many difficulty in adding new functions because of slow standardization of network and slow deployment of new services. To solve this problem, an active network can support the suitable environment to add new function such as self- adaptation. Therefore, this Paper suggests Self Adaptation Service(SAS) using agent-based active network and the constraint-based Service Creation Environment(SCE) to support self-adaptation with context-awareness. SAS provides benefits to support the context-aware service and the fast deployment of new services.

• The KIPS Transactions:PartA
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• v.12A no.6 s.96
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• pp.477-484
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• 2005

Applications in ubiquitous environments should provide the best services to users by considering the changes of users requirements and service environments, and should adapt service behaviors to the underlying platform's behaviors according to contextual changes. To reflect users requirements actively and provide more flexible services, we propose 2-level context adaptation method for supporting dynamic application adaptability in contextual changes. We offend the range of contexts to users requirements for supporting context adaptation. It can reflect users preferences in offering application services. For application adaptability, we use adaptation policies to allow applications require how they adapt to specific contexts, and to make them react actively on such situations.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.8 no.1
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• pp.42-51
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• 2008

We believe that smart spaces, offering pervasive services, will proliferate. However, at present, those islands of smart spaces should be joined seamlessly with each other. As users move about, they will have to roam from one autonomous smart space to another. When they move into the new island of smart space, they should setup their devices and service manually or not have access to the services available in their home spaces. Sometimes, there will conflicts between users when they try to occupy the same space or use a specific device at the same time. It will also be critical to elder people who suffer from Alzheimer or other cognitive impairments when they travel from their smart space to other visited spaces (e.g., grocery stores, museums). Furthermore our experience in building the Gator Tech Smart House reveals to us that home residents generally do not want to lose or be denied all the features or services they have come to expect simply because they move to a new smart space. The seamless inter-space interaction requirements and issues are raised automatically when the ubiquitous pervasive computing system tries to establish the user's service environment by allocating relevant resources after the user moves to a new location where there are no prior settings for the new environment. In this paper, we raise and present several critical inter-space interactions issues impacting middleware architecture design of ubiquitous pervasive computing. We propose requirements for resolving these issues on seamless inter-space operation. We also illustrate our approach and ideas via a service scenario moving around two smart spaces.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.329-329
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• 2006