• 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.

• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.3
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• pp.19-31
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• 2008

Currently, RFID is receiving attention from the industry and the academy because it is considered as an enabling technology for ubiquitous computing, in particular context perception. In this paper, we survey the existing context-aware RFID systems and introduce three main issues in the systems - the context information, the context-aware services, and the context-aware RFID system architectures. We classify context information into six groups, the services into five context-aware service types, and the systems into four architecture styles. This study will help stakeholders such as customers and developers to understand their RFID systems and to develop new services.

• Journal of Intelligence and Information Systems
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• v.13 no.2
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• pp.27-41
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• 2007

Nowadays the context-aware systems have been regarded as a promising opportunity to create differentiated e-marketplaces. Context-aware system aims to provide personalized services by understanding the user's current situation which is automatically acquired from the context data. This aim naturally leads us to a motivation to evaluate to what extent a system is context-aware. Even though lots of endeavors have stated about the level of context-aware system, a structured evaluation has been so far very rare. Hence, the purpose of this paper is to propose a two-phased methodology for assessing context-aware systems. In the first phase, we perform a requisite analysis to discriminate a context-aware system from general or context-based systems. Once an information system is recognized as context-aware system, then level of collaboration, mobility and embeddedness is derived to determine the level of context-aware system in the second phase. To do so, device collaboration diagram (DCD) is proposed to visualize the system architecture. Moreover, readiness and level of system are Jointly considered in the phase to provide a development strategy for each context-aware system development project. To show the feasibility of the idea proposed in this paper, legacy context-aware systems are actually analyzed and evaluated.

• 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.

• Journal of Information Processing Systems
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• v.10 no.4
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• pp.581-588
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• 2014

To facilitate the implementation of a wide variety of context-aware applications based on mobile devices, general-purpose context-aware framework that applications can use by calling is needed. The context-aware framework is a middleware that performs the sensing, reasoning, and retrieving based on the knowledge base. The knowledge base must systematically represent the information required on the behavior of the context-aware framework, such as context information and reasoning information. It must also provide functions for storage and retrieval. To date, previous research on the representation of the context information have been carried out, but studies on the unified representation of the knowledge base has seen little progress. This study defines the knowledge base as the unified context information, and proposes the UniOWL, which can do a good job of representing it. UniOWL is based on OWL and represents the information that is necessary for the operation of the context-aware framework. Therefore, UniOWL greatly facilitates the implementation of the knowledge base on a context-aware framework.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.8
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• pp.394-406
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• 2008

Even though context is the most important feature in context-aware systems, the existing requirements engineering cannot support methodology for elicitation and specification of contexts. In this paper, we propose a requirements elicitation method and a requirements specification method for context-aware systems. Our requirements elicitation method is a 6-stepped, incremental, and iterative process. At the beginning steps in the process, we identify the requirements for business logic. Afterwards, we gather the requirements for context logic, model contexts, and identify subsystems. For requirements specification, we suggest a context-aware use case diagram, a context diagram for context modeling, and a context-type-use-case-dependency diagram for the traceability of use cases on the change of context types. We also introduce a case study that we apply our approaches to a real system, and a qualitative evaluation of our approaches. Our study will help stakeholders to efficiently elicit requirements for context-aware systems and to specify them clearly.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.2
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• pp.119-124
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• 2016

According to the expansion of smartphone penetration and development of wearable device, personal context information can be easily collected. To use this information, the context aware recommender system has been actively studied. The key issue in this field is how to deal with the context information, as users are influenced by different contexts while rating items. But measuring the similarity among contexts is not a trivial task. To solve this problem, we propose context aware post-filtering to apply the context compensation. To be specific, we calculate the compensation for different context information by measuring their average. After reflecting the compensation of the rating data, the mechanism recommends the items to the user. Based on the item recommendation list, we recover the rating score considering the context information. To verify the effectiveness of the proposed method, we use the real movie rating dataset. Experimental evaluation shows that our proposed method outperforms several state-of-the-art approaches.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.6
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• pp.659-664
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• 2006

The Context-Aware system is the core technology in the Ubiquitous Computing Environment. Recently, the practical use of a sensor is magnified and the application fields of it are gradually extended in order to collect necessary context information. Context-Aware service integrates the context information which is collected by sensors, and then provides, a suitable service to a user through the process of analysis and reasoning. This service is studied in a variety of fields such as marketing, medical treatment, education and so on. In this paper, we analyze the method of recognizing surrounding context and the result of the awareness by using differential and structural property of multiple valued logic function; propose the model that provides appropriate service depending on the change of surrounding contort; confirm the applicability of the Context-aware system by showing the example of application.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.3
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• pp.300-305
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• 2005

Context-aware intelligent services are essential in ubiquitous computing and intelligent robots environments, which make decisions on which services to start with the consideration of surrounding contexts. In the ubiquitous and intelligent environments, context-aware service engines should be light-weighted due to the resource restrictions on the devices. This paper presents a context-aware service engine which is designed for light-weighted devices. The context-aware service engine has been designed with special attention to improve the execution speed and to minimize the memory requirement.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1984-1988
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• 2009

MRT has various surveillance systems for passenger's safety and facility protection which are consisted of fire detection, trespasser observation and so on. However, these systems are not closely related each other because it is designed just for its own purpose, so it could be make wrong decision to surveillance system without important information to determine an accident or disaster. For more accurate event detection, surveillance system needs total situation-aware method using complementary data. This study introduces context-aware system for complex and accurate event detection. Therefore, we apply context-aware system to MRT surveillance system, selecting context-aware parameters and appling them to it.