• International Journal of Fuzzy Logic and Intelligent Systems
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• 제8권4호
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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.

• 한국수학교육학회지시리즈A:수학교육
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• 제52권2호
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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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• 제18권2호
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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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• 제14권3호
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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.

• 대한수학교육학회지:수학교육학연구
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• 제22권1호
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• pp.101-115
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• 2012

유사성을 근거로 하는 개연적 추론인 유추는 수학뿐만 아니라 물리 등의 여러 분야에서 개념 형성, 문제해결, 새로운 발견 등을 위해 사용되는 하나의 사고전략이다. 통계교육자들은 통계에서도 역시 유추가 유용한 사고전략으로 사용될 수 있다고 언급한다. 본 연구에서는 수학과는 다른 특성을 지닌 통계에서 학생들의 유추적 사고의 특징을 살펴본다. 이를 위해 수학영재학급 학생들을 대상으로 실생활 맥락이 담긴 통계문제를 기저문제로 제시하고 이와 유사한 문제를 만들도록 하였다. 학생들이 만든 문제는 기저문제의 통계적 맥락의 보존 여부 및 기저문제의 기본구조 유지 여부에 따라 다섯 가지 유형으로 분류되었다. 각 유형의 특징을 분석한 결과 다음과 같은 시사점을 얻을 수 있었다. 통계에서는 기본구조가 유지되어도 통계적 맥락이 훼손되는 경우 그 문제의 의미를 찾을 수 없으나, 기본구조가 변형되었다 하더라도 통계적 맥락이 보존되는 경우 통계적 개념에 대한 재개념화에 기여할 수 있다는 가능성을 확인하였다.

• 대한수학교육학회지:학교수학
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• 제17권3호
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• pp.423-446
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• 2015

본 연구의 목적은 고등학교 확률 수업의 '몬티홀 문제' 과제 맥락에서 나타난 논증과 정의 특징을 알아보는 것이다. 고등학교 2학년 상 수준 한 학급의 학생을 대상으로 교사와 학생 사이의 논증과정에 관한 수업담화를 Toulmin의 논증패턴을 이용하여 분석한 결과, 논증 중심의 담화 공동체로 만들기 위한 과제 맥락과 학생들이 질문하고 반박할 수 있는 안전한 교실 문화의 중요성이 밝혀졌다. 또한 복잡한 문제를 함께 해결해 나가는 논증과정을 통해 학생들은 수업에 더 몰입하게 되었으며, 실제적인 경험적 맥락은 개념의 이해를 풍부하게 해 주었다. 그러나 논증과정에서 나타난 추론은 통계적 추론이 아니라 대부분 확률 문제 풀이 위주의 수학적 추론이 나타났다. 이러한 연구 결과는 맥락에 따라 결과를 해석하는 과정에서 학생들의 통계적 추론이 일어남을 교사가 이해할 필요가 있고, 과제 맥락과 질문을 통해 학생들이 논증과정에 적극적으로 참여하도록 해야 한다는 확률 통계 수업에 대한 시사점을 제공할 수 있다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제16권2호
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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.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2005년도 춘계학술대회
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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.

• 한국초등과학교육학회지:초등과학교육
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• 제17권1호
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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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• 제4권5호
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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.