• Journal of KIISE
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• v.43 no.7
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• pp.763-772
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• 2016

With the spread of smartphones containing multiple on-board sensors, the market for context aware applications have grown. However, due to the limited power capacity of a smartphone, users feel discontented QoS. Additionally, context aware applications require the utilization of many forms of context and sensing information. If context transition has occurred, types of needed sensors must be changed and each sensor modules need to turn on/off. In addition, excessive sensing has been found when the context decision is ambiguous. In this paper, we focus on power consumption associated with the context transition that occurs during indoor/outdoor detection, modeling the activities of the sensor associated with these contexts. And we suggest a freezing algorithm that reduces power consumption in context transition. We experiment with a commercial application that service is indoor/outdoor location tracking, measure power consumption in context transition with and without the utilization of the proposed method. We find that proposed method reduces power consumption about 20% during context transition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4227-4239
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• 2013

Knowledge transfer occurs in various social contexts, within individuals and groups, and, thus, is closely linked to social networks in an organization. This paper applies social network theory and social identity theory to knowledge management area. The subject of this study was organization members who transfer their knowledge. 296 questionnaires were collected and analyzed. The results are as follows. First, in-group and out-group's tie strength have a significant effect on knowledge transfer. Second, the study shows that the knowledge transfer influences positively individual, team and organizational performance. Lastly, the study verifies that the applied knowledge has a moderating effect on the relationship of the in-group's tie strength and knowledge transfer.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.4
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• pp.239-250
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• 2013

Context-aware mobile computing has become the primary approach to realize automatic, autonomous, and user-centric computing in the context of largely increasing the amount of mobile devices used that embed available sensors. However, designing an inference engine nonetheless requires the tasks of analyzing contexts, situations that can be inferred, etc. Moreover, a mobile device has limited resources and limited computation capability, which results in recognizing the common sense of its unsuitable environment for processing inference. Hence, we propose context-situation reasoning elements and their formal models in this paper, and we verify the formal models' applicability by applying them to an example. Finally, we design and implement an inference engine that realize the context-situation inference elements in computing environment, and we experiment an example by using the proposed inference engine to verify applicability and reusability of the inference engine.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.343-350
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• 2015

This paper presents a context recognition method using environmental sound signals, which is applied to a mobile-based client monitoring system. Seven acoustic contexts are defined and the corresponding environmental sound signals are obtained for the experiments. To evaluate the performance of the context recognition, MFCC and LPCC method are employed as feature extraction, and statistical pattern recognition method are used employing GMM and HMM as acoustic models, The experimental results show that LPCC and HMM are more effective at improving context recognition accuracy compared to MFCC and GMM respectively. The recognition system using LPCC and HMM obtains 96.03% in recognition accuracy. These results demonstrate that LPCC is effective to represent environmental sounds which contain more various frequency components compared to human speech. They also prove that HMM is more effective to model the time-varying environmental sounds compared to GMM.

• Journal of the Korean Geographical Society
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• v.41 no.4 s.115
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• pp.470-490
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• 2006

The paper critically examines resource mobilization theories, frame theory, and new social movement theories, and proposes studies on the spatiality of the social movements as one potential to mitigate the limitation in these theories. The resource mobilization theories and the frame theory, the strategy-oriented approaches, lack contextual understandings of the origin of social movements. While new social movement theories provide macro-scale analysis and the structural explanations of the origins of social movements, they have covered limited geographical areas. The spatiality of social movements promotes deep understandings of local differences, and contexts in and through which grievances are constructed and collective actions are organized. Physical structures and symbolic representations of places are often created and utilized as social movement strategies. The spatiality of social movements can be a useful conceptual tool to explain the diversity and the dynamics of social movements.

• Journal of Preventive Medicine and Public Health
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• v.46 no.sup1
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• pp.28-34
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• 2013

Physical activity (PA) professionals and participants recognize enhanced quality of life (QoL) as a benefit of and motivator for PA. However, QoL measures are often problematic and rarely consider the participants' perspective. This paper focuses on recent findings from a larger project on the role of QoL in PA and health promotion. More specifically, we focus on the views of participants and potential participants to better understand the relationship of PA and QoL. In earlier stages of the project we began with a conceptual model of QoL and developed a survey. We now focus on participants' views and ask two questions: 1) what is QoL? and 2) how does PA relate to QoL? We first asked those questions of a large sample of university students and community participants as open-ended survey items, and then asked focus groups of community participants. Overall, participants' responses reflected the multidimensional, integrative QoL model, but the responses and patterns provided information that may not be picked up with typical survey measures. Findings suggest that PA contributes to multiple aspects of QoL, that social and emotional benefits are primary motivators and outcomes for participants, and that the meaning of QoL and PA benefits is subjective and contextualized, varying across individuals and settings. Programs that directly target and highlight the multiple dimensions and integrative QoL, while considering the individual participants and contexts, may enhance both PA motivation and participants' health and QoL.

• Education of Primary School Mathematics
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• v.6 no.1
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• pp.11-28
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• 2002

The purposes of this study were to analyze elementary school mathematics textbooks developed in accordance with the 7th national amended curriculum and to find implications for the development of a new revised curriculum to meet the needs of the knowledge-based society. Elementary school mathematics textbooks and accompanying practice books were analyzed. Teacher's manuals were also studied to examine the intentions of the textbook developers. The two major questions were sought. First, to what degree do elementary school mathematics textbooks and practice books match with the intentions of the national curriculum\ulcorner Second, how do elementary school mathematics textbooks and practice books facilitate student's learning for understanding mathematics\ulcorner The findings were as follows. First textbooks, practice books, and teacher's manuals appeared not to reflect the intentions of the 7th amended curriculum to the full extent. Second, characteristics and roles of textbooks, practice books, and teacher's manuals were not clearly defined and therefore, they were not very feasible for teaming for understanding mathematics. The recommendations for a new revised curriculum were suggested. First, regarding the contents presented in the textbooks, the idea of structure of subject matter need to be considered in order to help students to understand connections of concepts and relationships between concepts and functions in mathematics. Second, more ill defined problems should be presented to develop problem solving ability in real life contexts in students. Third, contents for relearning and enrichment need to be reorganized to reflect students' real ability. Fourth, uses of the concrete and the manipulative need to be more realistically suggested. Fifth, more prototypes of performance assessment tasks, scoring rubrics, and portfolios need to be presented in a more teacher-friendly manner. Sixth, characteristics and roles of textbooks and practice books need to be more discernible.

• Education of Primary School Mathematics
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• v.19 no.1
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• pp.61-78
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• 2016

The purpose of this study was to investigate the perceptions and perspectives on meanings and use of manipulatives in mathematics lessons. For the investigation, the researcher reviewed related literature and analyzed the perceptions of preservice teachers on the meanings and use of manipulatives in mathematics lessons. The participants were 75 preservice elementary school teachers who took a teaching practice course at the 1st or the 2nd semester in 2015. These preservice teachers observed mathematics lessons for two weeks during the student teaching periods. They were requested to observed the use of manipulatives in mathematics lessons and wrote about their ideas on the meanings and use of manipulatives. Result of the research was that the perceptions on the meanings and use of manipulatives from the preservice teachers' perspectives are as follows. Manipulatives in mathematics lessons were self-made or pre-made manufactures. The using time of manipulatives during lessons varies, and the teachers provide the manipulatives with contexts. Providing in-depth observation during a teaching practice course is allowed opportunities for preservice teachers to reflect their mathematics teaching and learning methods in the classroom.

• Education of Primary School Mathematics
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• v.19 no.1
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• pp.19-30
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• 2016

This study examined pre-service teachers' pedagogical content knowledge of fraction division in a context where they were asked to write a story problem for a symbolic expression illustrating a whole number divided by a proper fraction. Problem-posing is an important instructional strategy with the potential to create meaningful contexts for learning mathematical concepts, especially when real-world applications are intended. In this study, story problems written by 135 elementary pre-service teachers were analyzed with respect to mathematical correctness. error types, and division models. Patterns and tendencies in elementary pre-service teachers' knowledge of fraction division were identified. Implicaitons for teaching and teacher education are discussed.

• Journal of Internet Computing and Services
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• v.16 no.5
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• pp.75-86
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• 2015

Internet of Thing (IoT) computing is an environment where various devices with sensors and actuators are connect, and interact together to acquire contexts and provide useful services. With the advances of IoT technologies, its usability becomes an in important issue. However, there exist various types of faults in IoT computing which are not conventionally addressed in software research community. Providing reliable IoT services is challenging. In this paper, we present a hierarchy of IoT faults and analyze causes and symptoms of the faults. Based on the analysis, we define effective methods for managing IoT faults. We believe that our proposed framework for managing IoT faults can be utilized in reducing the development cost of IoT applications and enhancing the quality of the applications.