• 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 Mathematical Education
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• v.52 no.2
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• pp.217-230
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• 2013

This study attempts to propose the construction of textbook contents of fraction division and to suggest a method to strengthen the connection among problem context, manipulation activities and symbols by proposing an algorithm of dividing fractions based on problem contexts. As showing the suitable algorithm to problem context, it is able to understand meaningfully that the algorithm of fractions division is that of multiplication of a reciprocal. It also shows how to deal with remainder in the division of fractions. The results of this study are expected to make a meaningful contribution to textbook development for primary students.

• Educational Technology International
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• v.18 no.2
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• pp.249-263
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• 2017

The purpose of this study was to examine whether respondents showed gender differences in life- learning competency, self-directed learning ability, problem-solving ability, and academic achievement and to identify relationships among variables of university students in the context of higher education. To address those goal, the data set was analyzed that nationally collected from Korea Youth Competency Measurement and International Comparative Research III by National Youth Policy Institute in South Korea. 680 samples were used in the study that were 343 males and 337 females of university students. As results, statistically significant difference was showed in the participants' gender. Male university students were higher score than female university students in All variables. Also, learning agility in life-learning competency was strongly related to self-directed learning ability and problem-solving. Thinking skills in life-learning competency was strongly related to academic achievement in university students in higher education. In terms of learning strategy in the context of higher education, some suggestions have been made for university students.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.3
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• pp.1263-1279
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• 2020

Activating appropriate roles for a session in the role-based access control (RBAC) model has become challenging because of the so-called role explosion. In this paper, factors and issues related to user-driven role management are analysed, and a session role activation (SRA) problem based on reasonable assumptions is proposed to describe the problem of such role management. To solve the SRA problem, we propose an extended RBAC model with context-based role filtering. When a session is created, context conditions are used to filter roles that do not need to be activated for the session. This significantly reduces the candidate roles that need to be reviewed by the user, and aids the user in rapidly activating the appropriate roles. Simulations are carried out, and the results show that the extended RBAC model is effective in filtering the roles that are unnecessary for a session by using predefined context conditions. The extended RBAC model is also implemented in the Apache Shiro framework, and the modifications to Shiro are described in detail.

• Journal of Educational Research in Mathematics
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• v.22 no.1
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• pp.101-115
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• 2012

Analogy, a plausible reasoning on the basis of similarity, is one of the thinking strategy for concept formation, problem solving, and new discovery in many disciplines. Statistics educators argue that analogy can be used as an useful thinking strategy in statistics as well. This study investigated the characteristics of students' analogical thinking in statistics. The mathematically gifted were asked to construct similar problems to a base problem which is a statistical problem having a statistical context. From the analysis of the problems, students' new problems were classified into five types on the basis of the preservation of the statistical context and that of the basic structure of the base problem. From the result, researchers provide some implications. In statistics, the problems, which failed to preserve the statistical context of base problem, have no meaning in statistics. However, the problems which preserved the statistical context can give possibilities for reconceptualization of the statistical concept even though the basic structure of the problem were changed.

• School Mathematics
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• v.17 no.3
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• pp.423-446
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• 2015

This study aims to look into the characteristics of argumentation in the task context of 'Monty Hall problem' at a high school probability class. As a result of an analysis of classroom discourses on the argumentation between teachers and second-year students in one upper level class in high school using Toulmin's argument pattern, it was found that it would be important to create a task context and a safe classroom culture in which the students could ask questions and refute them in order to make it an argument-centered discourse community. In addition, through the argumentation of solving complex problems together, the students could be further engaged in the class, and the actual empirical context enriched the understanding of concepts. However, reasoning in argumentation was mostly not a statistical one, but a mathematical one centered around probability problem-solving. Through these results of the study, it was noted that the teachers should help the students actively participate in argumentation through the task context and question, and an understanding of a statistical reasoning of interpreting the context would be necessary in order to induce their thinking and reasoning about probability and statistics.

• 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.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2005.05a
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• pp.131-138
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• 2005

Recommender systems have been widely advocated as a way of coping with the problem of information overload in e-business environment. Most of the existing recommender systems focused on what kind of items to recommend, although when to recommend to the target customer considering their context is an important issue. Even right item might be a spam advertisement or wrong recommendation for the customer if it can not be recommended at the right context. It is particularly important for recommendations where the user's context is changing rapidly, such as in both handheld and ubiquitous computing environment. Therefore, we propose CARS (Context-Aware Recommender System) based on CBR and context-awareness for ubiquitous computing environment. CBR is used to generate a target customer class and proper context. Context-awareness is used to gather suer context information from sensors, networks, device status, user profiles, and other sources. An illustrative case example is suggested to explain the procedure of CARS.

• Journal of Korean Elementary Science Education
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• v.17 no.1
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• pp.75-87
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• 1998

The problem solving processes of elementary school children who are talented in science have been seldom studied. Researchers often resort to thinking aloud method to collect data of problem solving processes. The major purpose of the study is investigating high ability elementary school students' problem solving processes through the analysis of written responses to science problems in everyday context. 67 elementary students were participated Chungcheongbuk-do Elementary Science Contest held on October, 1997. The written responses of the contest participants to science problems in everyday context were analyzed in terms of problem solving processes. The findings of the research are as follows. (1) High ability elementary students use various concepts about air and water in the process of problem solving. (2) High ability elementary students use content specific problem solving strategies. (3) The problem solving processes of the high ability elementary students consist of problem representation, problem solution, and answer stages. Problem representation stage is further divided into translation and integration phases. Problem solving stage is composed of deciding relevant knowledge, strategy, and info..ins phases. (4) High ability elementary students' problem solving processes could be categorized into 11 qualitatively different groups. (5) Students failures in problem solving are explained by many phases of problem solving processes. Deciding relevant knowledge and inferring phases play major roles in problem solving. (6) The analysis of students' written responses, although has some limitations, could provide plenty of information about high ability elementary students' problem solving precesses.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.5
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• pp.836-858
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• 2010

Web Services allow a user to integrate applications from different platforms and languages. Since mobile applications often run on heterogeneous platforms and conditions, Web Service becomes a popular solution for integrating with server applications. However, because of its verbosity, XML based SOAP messaging gives the possible overhead to the less powerful mobile devices. Based on the mobile client's behavior that it usually exchanges messages with Web Service continuously in a session, we design the Handheld Flexible Representation architecture. Our proposed architecture consists of three main components: optimizing message representation by using a data format language (Simple_DFDL), streaming communication channel to reduce latency and the Context-store to store context information of a session as well as redundant parts of the messages. In this paper, we focus on the Context-store and describe the architecture with the Context-store for improving the performance of mobile Web Service messaging. We verify our approach by conducting various evaluations and investigate the performance and scalability of the proposed architecture. The empirical results show that we save 40% of transit time between a client and a service by reducing the message size. In contrast to solutions for a single problem such as the compression or binarization, our architecture addresses the problem at a system level. Thus, by using the Context-store, we expect reliable recovery from the fault condition and enhancing interoperability as well as improving the messaging performance.