• Journal of KIISE:Computing Practices and Letters
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• v.12 no.4
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• pp.254-263
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• 2006

Ontology-based context models are widely used in ubiquitous computing environment because they have advantages in the acquisition of conceptual context through inferencing, context sharing, and context reusing. Among the benefits, inferencing enables context-aware applications to use conceptual contexts which cannot be acquired by sensors. However, inferencing causes processing delay and thus becomes the major obstacle to the implementation of context-aware applications. The delay becomes longer as the amount of contexts increases. In this paper, we propose a context pre-fetching method to reduce the size of contexts to be processed in a working memory in attempt to speed up inferencing. For this, we extend the query-tree method to identify contexts relevant to the queries of a context-aware application. Maintaining the pre-fetched contexts optimal in a working memory, the processing delay of inference reduces without the loss of the benefits of ontology-based context model. We apply the proposed scheme to our ubiquitous computing middleware, Active Surroundings, and demonstrate the performance enhancement by experiments.

• Journal of KIISE:Software and Applications
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• v.36 no.4
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• pp.283-290
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• 2009

Context-awareness is one of the key features of ubiquitous paradigm. A methodology that is specifying the relationships between the contexts and services needs to be developed to intelligently and sensitively deal with dynamic environment. The existing models on context-aware modeling are difficult to verify the correctness of models with respect to timeliness. In this paper we propose an approach which includes timing constraint in the relations of the context model, and verify its effectiveness using colored Petri-Net. Moreover, a context-modeling toolkit including context-awareness engine and simulator is developed to support agent-based context-aware service. The effectiveness of the proposed methodology is demonstrated using an example of Usilvercare.

• Journal of Communications and Networks
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• v.13 no.6
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• pp.567-582
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• 2011

The growing popularity of the Internet has caused the size and complexity of communications and computing systems to greatly increase in recent years. To alleviate this increased management complexity, novel autonomic management architectures have emerged, in which many automated components manage the network's resources in a distributed fashion. However, in order to achieve effective collaboration between these management components, they need to be able to efficiently exchange information in a timely fashion. In this article, we propose a context dissemination framework that addresses this problem. To achieve scalability, the management components are structured in a hierarchy. The framework facilitates the aggregation and translation of information as it is propagated through the hierarchy. Additionally, by way of semantics, context is filtered based on meaning and is disseminated intelligently according to dynamically changing context requirements. This significantly reduces the exchange of superfluous context and thus further increases scalability. The large size of modern federated cloud computing infrastructures, makes the presented context dissemination framework ideally suited to improve their management efficiency and scalability. The specific context requirements for the management of a cloud data center are identified, and our context dissemination approach is applied to it. Additionally, an extensive evaluation of the framework in a large-scale cloud data center scenario was performed in order to characterize the benefits of our approach, in terms of scalability and reasoning time.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.205-211
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• 2008

Conventional context-aware service models permit the access of resources only by user authentication, but the ubiquitous environments where the context information around users is changing frequently require the resource access control according to the rapid changes. This paper proposes a scheme to control access permission of resource dynamically as context information of user changes. Our access control model is based on traditional CASA (Context-Aware Security Architecture), but can restrict the access of the user already has been authorized. With the real-time checking of context information, our scheme gives different access controls according to changes in environmental information, and provides more secure services than conventional context-aware models.

• Journal of Audiology & Otology
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• v.25 no.3
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• pp.124-130
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• 2021

Background and Objectives: The study investigated vowel context effects on the perception of stop consonants in Malayalam. It also probed into the role of vowel context effects in determining the frequency of occurrence of various consonant-vowel (CV) syllables in Malayalam. Subjects and Methods: The study used a cross-sectional pre-experimental post-test only research design on 30 individuals with normal hearing, who were native speakers of Malayalam. The stimuli included three stop consonants, each spoken in three different vowel contexts. The resultant nine syllables were presented in original form and five gating conditions. The consonant recognition in different vowel contexts of the participants was assessed. The frequency of occurrence of the nine target syllables in the spoken corpus of Malayalam was also systematically derived. Results: The consonant recognition score was better in the /u/ vowel context compared with /i/ and /a/ contexts. The frequency of occurrence of the target syllables derived from the spoken corpus of Malayalam showed that the three stop consonants occurred more frequently with the vowel /a/ compared with /u/ and /i/. Conclusions: The findings show a definite vowel context effect on the perception of the Malayalam stop consonants. This context effect observed is different from that in other languages. Stop consonants are perceived better in the context of /u/ compared with the /a/ and /i/ contexts. Furthermore, the vowel context effects do not appear to determine the frequency of occurrence of different CV syllables in Malayalam.

• Korean Journal of Child Studies
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• v.25 no.4
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• pp.33-48
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• 2004

The purpose of this study was to examine if mothers and their children used different interaction strategies depending on the interacting contexts. Sixty-five mothers and their children were observed while they interacted with each other in two contexts, that is, a free play context and a joint problem solving context. The result of this study showed that first, the mothers' strategies and their children's strategies were closely related. When the mothers used positive strategies, their children also responded with positive strategies. In contrast, when the mothers used negative strategies, their children also tended to use negative strategies. Second, the contexts which the mothers and their children interacted affected the strategies that the mothers and their children used. The mothers and the children were more likely to use positive strategies in the context of free play than in the context of the joint problem solving. This result points out the importance of free play as the context of producing a positive atmosphere where the mothers and their children interacted positively and had a good time. Suggestions for further study and implications for parents were provided.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.2
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• pp.143-148
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• 2005

In this paper, we introduce smart home service based on ubiquitous environment and context awareness. We define the multi- context environment and the context collision caused by many user that the existing study of smart home is unconcerned with. Heal home is the space where various contexts are created and disappeared in. Smart home appliances are restricted within their service. We divide the home space by main uses of rooms and group smart service by sensory organ. And we introduce the multi-context manager consist with context interpreter, context collision manager and smart service manager.

• Korean Institute of Interior Design Journal
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• v.19 no.3
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• pp.251-259
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• 2010

The purpose of this study is to show the characteristics of integrated welfare center space by applying Context-Awareness technology in order to provide user-friendly services for efficient use of integrated welfare centers as more and more people are interested in using welfare integrated welfare centers which have increasingly been supplied. For this study, we propose the spaces which provide users of integrated welfare centers with proper services by applying Context-Awareness after reviewing the theory of Context-Awareness through literature study as well as case analysis and choosing the reasonable Context-Awareness technology for integrated welfare centers. As it is possible to efficiently provide users with safety service, information service and convenient service by the analysis of space, users' movement in lobby where Context-Awareness is applied and the lobbies of integrated welfare centers in Munsan area, Paju-si out of domestic cases about integrated welfare centers, the different type of spaces from the existing one is expected.

• Journal of The Korean Association For Science Education
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• v.24 no.4
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• pp.774-784
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• 2004

In the previous study, six factors which could disturb students' problem solving in an everyday context were identified and discussed. In this study, teaching materials to help students overcome those disturbing factors for successful problem solving in an everyday context were developed and applied to twenty-nine grade 10 students, and the effects of teaching materials were analyzed. According to the analysis of the correlation between the performance in everyday context problem solving and the benefit from the teaching materials, it was found that students who received the help from the teaching materials showed better performance with statistical significance. And students noted that teaching materials were helpful for them to solve the physics problems. Analyzing the overall performance of students in solving the everyday context problem, students in the experimental group showed better performance than the control group and this performance difference was larger among low-score students in school science testing. However, these differences were not statistically significant because the sample size was small. And, based on the analysis of interviews with students, it was also found that some students who showed low performance might not receive help from the teaching materials because the materials were too complex to be read easily, or because the basic concepts needed to solve the problem were not understood. Therefore, the results obtained from the interviews will be used to design more effective teaching for problem solving in an everyday context.

• 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.