• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.6
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• pp.187-195
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• 2009

Recently, with the development of ubiquitous computing, the study and development about context awareness models is required for the application of ubiquitous environment. This paper presents the design and implementation of a matrix based context awareness model for vehicle environment. The matrix construction method using 5W1H and CAM (Context Awareness Model) expression is proposed for context awareness modeling. The system with the proposed model is implemented by Zigbee modules for the recognition of individual identification and position and a navigator for current spatial and temporal information of GPS. The result of experiments shows that the proposed model is available.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.8 no.4
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• pp.254-259
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• 2008

Uncertainty of result of context awareness always exists in any context-awareness computing. This falling-off in accuracy of context awareness result is mostly caused by the imperfectness and incompleteness of sensed data, because of this reasons, we must improve the accuracy of context awareness. In this article, we propose a novel approach to model the uncertain context by using ontology and context reasoning method based on Bayesian Network. Our context aware processing is divided into two parts; context modeling and context reasoning. The context modeling is based on ontology for facilitating knowledge reuse and sharing. The ontology facilitates the share and reuse of information over similar domains of not only the logical knowledge but also the uncertain knowledge. Also the ontology can be used to structure learning for Bayesian network. The context reasoning is based on Bayesian Networks for probabilistic inference to solve the uncertain reasoning in context-aware processing problem in a flexible and adaptive situation.

• The Journal of the Korea Contents Association
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• v.11 no.2
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• pp.22-30
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• 2011

In the IT convergence environment changed with not only the quality but also the material abundance, it is the most crucial factor for the strategy of personalized recommendation services to investigate the context information. In this paper, we proposed the recommendation using the service ontology based context awareness modeling. The proposed method establishes a data acquisition model based on the OSGi framework and develops a context information model based on ontology in order to perform the device environment between different kinds of systems. In addition, the context information will be extracted and classified for implementing the recommendation system used for the context information model. This study develops the ontology based context awareness model using the context information and applies it to the recommendation of the collaborative filtering. The context awareness model reflects the information that selects services according to the context using the Naive Bayes classifier and provides it to users. To evaluate the performance of the proposed method, we conducted sample T-tests so as to verify usefulness. This evaluation found that the difference of satisfaction by service was statistically meaningful, and showed high satisfaction.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.3
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• pp.304-309
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• 2007

What is important in ubiquitous computing is collecting users' context information from various sensors and providing services suitable for use's current situation. Particularly in mobile environment, each area has different context awareness structure and this makes it difficult to share information with other areas. As a result, context resources for recognizing users' context ate insufficient. Moreover, because mobile devices have a limited processing capacity, there are difficulties in the real time analysis of users' context. This paper proposed a context awareness and integration model for analyzing users' context actively and providing adaptive services using mobile devices. The proposed model distinguishes users' context between dynamic and static structure to analyze the context, and obtains context resources by sharing context information of users within an area.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.382-389
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• 2006

Developing context awareness service In these day, It demands high security in context awareness service. So GEO-RBAC that provide user assignment of spatial role, assignment of permission, role schema, role instance and spatial role hierarchy to context awareness service is access control model to perfect in context awareness service. But GEO-RBAC is not considering temporal constraints that have to need context awareness environment. Consequently this paper improves the flexibleness of GEO-RBAC to consider time and period constraints notion and the time of GTRBAC that presents effective access control model. also we propose GEO-RBAC to consider temporal constraints for effective access control despite a various case.

• Journal of the Korean Society for information Management
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• v.28 no.3
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• pp.123-139
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• 2011

Context-awareness as a key technology of ubiquitous computing needs a context model that understands and processes situational information coming from diverse sensors and devices, and can be applied diversely in various domains. Semantic web based ontologies use structured standard format and express meaning of information, so it is possible to recognize effectively context-awareness situations, allowing the system to share information and understand situation by inference. In this paper, we propose a layered ontology model to support generality and scaleability of the context-awareness system, and applied the model to u-Convention domain. In addition, we propose a effective reasoning method to handle compound situation by combining OWL-DL and SWRL rules.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.4
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• pp.423-429
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• 2006

The systems in the ubiquitous computing environment need to provide users with context-aware services, intelligently interacting with the surrounding environment. Therefore, the systems in the ubiquitous computing environment require context-awareness ability in order to gather and analyze context information in various situations and environments. However, existing context-aware systems lack the ability to systematically generate and handle various types of context information, and only a few systems have ability learning from environment. In this paper, a general context model is defined to describe various contexts and a context-awareness framework is implemented based in the model, which makes it straightforward to handle and generate various types of context from diverse sensor. The framework is designed to allow a system to sensed, combined, inferred, and learned context information, in order to provide users with services in dynamic environments. We have implemented the proposed framework and applied it to a u-Health management system.

• Journal of Information Technology Services
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• v.9 no.1
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• pp.113-125
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• 2010

Recently, a smart space with Ubiquitous Environment is expanding rapidly due to the development of Ubiquitous Sensor Network. Therefore, more appropriate and intelligent services of the context awareness system is being required. The previous context awareness system can provide a service to the user through the inference only on the current situation. But, it does not handle certain situation properly when the system provides abnormal result. Also it does not have any proper method of generating reliable semantic data from sensed raw data. In this paper, we are trying to solve the problems as the following approaches. First, the system recognizes abnormal result and corrects it by learning feedback from the user. Second, we suggest a method of converting sensed data into more reliable semantic data. Third, we build the system based on an Ontological context model that is capable of interoperability and reusability. Therefore, the context awareness system of our study can enhance the previous system that can generate more reliable context data, can provide more effective inference method, and can provide more intelligent system structure.

• Journal of Korea Spatial Information System Society
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• v.12 no.1
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• pp.28-36
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• 2010

Some context is characterized by a single event in computing environment, but many other contexts are determined by a lot of things which occur with a space and a time. The Realtime Sensor Network context-awareness service that interacts with the physical space can have property such as time. A methodology that is specified the relationship between the contexts and the service needs to be developed to Realtime context-awareness deal with spatio-temporal. In this paper, we propose an approach which should include spatio-temporal property in the context model, and verify its effectiveness using enhanced Petri-Net. The context-awareness service modeling of Realtime Sensor Network is discussed the properties of model such as basic Petri-Net, patterned Petri-Net, or Spatio-temporal Petri-Net. The proposed methodology demonstrated using an example that is SAEMANGUEM warming watching system. The use of Spatio-temporal Petri-Net will contribute not only to develop the application but also to model the spatio-temporal context awareness.

• Journal of Internet Computing and Services
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• v.7 no.5
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• pp.123-134
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• 2006

In this research paper, We have proposed an interpretation structure concerned with context-awareness which is essential to provide intelligent service. The proposed model has an interpretation structure that integrated information of both external and internal context, and been designed to keep independency between context information and application service. To verify the interpretation structure that proposed, we established a test bed (Ubi-Class) in which the concept of context awareness has been introduced to the existing class room, and constituted a scenario, and tested whether intelligent service is performed according to context interpretation.