• Journal of the HCI Society of Korea
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• v.8 no.1
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• pp.11-17
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• 2013

Context aware systems are those systems that are aware about the environment and perform productive functions automatically by reducing human computer interactions(HCI). In this paper, we present common architecture principles of context-aware systems to explain the important aspects of context aware systems. Our study focuses on identifying common concepts in pervasive computing approaches, which allows us to devise common architecture principles that may be shared by many systems. The principles consists of context sensing, context modeling, context reasoning, context processing, communication modelling and resource discovery. Such an architecture style can support high degree of reusability among systems and allows for design flexibility, extensibility and adaptability among components that are independent of each other. We also propose a new architecture based on broker-centric middleware and using ontology reasoning mechanism together with an effective behavior based context agent that would be suitable for the design of context-aware architectures in future systems. We have evaluated the proposed architecture based on the design principles and have done an analyses on the different elements in context aware computing based on the presented system.

• Proceedings of the Korea Contents Association Conference
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• 2013.05a
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• pp.51-52
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• 2013

Recent advances in WSN and the wide use of social sensing technologies have been changing our daily lives. In the process of creating intertwining connections and interconnections greatly influencing on the way we communicate with other people, WSN and social communication media have a number of important capabilities that support their utilization in distress broadcast during emergency situations. This paper proposes a system model that makes better utilization of WSN and social sensing capabilities in sending out distress messages to the intended recipients more efficiently and effectively.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.295-295
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• 2006

• Spatial Information Research
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• v.18 no.1
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• pp.101-107
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• 2010

Context-aware technologies have become the one of core technologies for intelligent urban geospatial services in ubiquitous computing environment. To provide context-aware intelligent services, various technologies including for context-aware modelling, context-aware sensing and context-aware service middleware are required. Among them, especially, ontologies are very useful for modelling, interpreting and reasoning context informations across various domains. In this research, the recent trends of context-awareness technologies and ontologies are reviewed to build a conceptual architecture for intelligent urban geospatial services. Considering it, the strategies of intelligent urban geospatial services are proposed.

• Journal of Internet Computing and Services
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• v.12 no.4
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• pp.35-43
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• 2011

Cognitive Radio (CR) ad hoc network is highly considered as one of promising future ad hoc networks, which enables opportunistic access to under-utilized licensed spectrum. Similarly to other CR networks, the spectrum sensing is a prerequisite in CR ad hoc network. Collaborative spectrum sensing can help increasing sensing performance. For such an infrastructureless network, however the coordination for the sensing collaboration is really complicated due to the lack of a central controller. In this paper, we propose a novel collaborative spectrum sensing scheme in which the final decision is made by the node with the highest data reliability based on a sequential Dempster Shafer theory. The collaboration of sensing data is also executed by the proposed contention-aware reporting mechanism which utilizes the sensing data reliability order for broadcasting spectrum sensing result. The proposed method reduces the collecting time and the overhead of the control channel due to the efficiency of the ordered sequential combination while keeping the same sensing performance in comparison with the conventional cooperative centralized spectrum sensing scheme.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.546-549
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• 2005

It is evident that advancement of ubiquitous technologies in the near future guarantees more convenient and plentiful living. With regarding to car life, we dream of an automatic driving without any effort of operation. This paper touches the realization issue, a convergence of wireless sensor network and Telematics specializing on an information routing mechanism between participating components in Telematics sensor communication network. We list up new requirements of wireless sensor network deployed for Telematics services. Then context-aware routing architecture is proposed in order to solve these constraints, in which a network topology for routing can be dynamically configured according to the combination of context models of network components.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.715-717
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• 2003

Some previous works for nearest neighbor (NN) query processing technique can treat a case that query/data are both moving objects. However, they cannot find exact result owing to vagueness of criterion. In order to escape their limitations and get exact result, we propose new NN query techniques, exact CTNN (continuous trajectory NN) query, approximate CTNN query, and dynamic CTNN query. These are all superior to pervious works, by reducing of number of calculation, considering of trajectory information, and using of continuous query concept. Using these techniques, we can solve any situations and types of NN query in location-aware environment.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.9
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• pp.621-628
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• 2013

This paper presents a framework for context-aware smart phone applications based on Android. The mobile context-aware system is composed of a low level context collection module, a high level context generation module and a service provision module. Existing android system cannot provide an appropriate application framework to integrate these independent modules. In this paper, we provide an application framework which make each module a component, and provide appropriate services to each component. This framework hides the Android platform, so that the complexity for organical combination can be minimized and the application developers can make the mobile context-aware applications easily.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.5
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• pp.1-8
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• 2012

A Smart phone is the one of the mobile devices widely used in our daily life. Moreover, various type of sensing data gathering from smart phone are effectively applicable to recognize of their users or smart phone status. Therefore, many smart phone applications based on sensor data have been actively developed. In this paper, we investigate an unexpected conditions recognition method using continuous sensing data from a single three-axis accelerometer. In addition, we implemented an application using the proposed method which provides the services notifying an abrupt changes of the smart phone conditions. By the experimented results, the application can be useful to protect the smart phone on the user's unaware conditions such as falling or a robbery case.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6A
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• pp.484-493
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• 2009

For the flexible frequency utilization, cognitive radio technique has been prominently considered. The most important requirement in cognitive radio networks is to protect the communications of primary users. Spectrum sensing task by secondary users should be seriously considered in cognitive radio networks, since the spectrum sensing process makes their current quality of service worse. In this paper, we propose the channel sensing scheduling method that keeps the requirements for protecting the primary and guarantee the secondary user's quality of service as possible. The quality of service of secondary user is analyzed in terms of packet delay and loss while the protection-requirements in terms of sensing interval and sensing time predefined. In numerical analysis, we can get appropriate parameters which guarantee QoS in various environment. And simulation results show that this method can improve the performance, delay and the number of transmitted packets against consecutive sensing method.