• Title/Summary/Keyword: Context model

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A Hierarchical Mobile Context Model and User Context Inference Methods based on Smart Phones (스마트 폰 기반 계층적 모바일 컨텍스트 모델 및 사용자 상황 추론 기법)

  • Lee, Meeyeon;Lee, Jung-Won;Park, Seung Soo
    • Journal of Software Engineering Society
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    • v.24 no.1
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    • pp.19-26
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    • 2011
  • Since smart phones have various embedded sensors and high portability/usability, they have emerged as suitable targets to collect information and to provide intelligent services. That is, with a smart phone, we can collect information about user's circumstances and phone usage from sensors and infer his/her current state which is the significant basis for context-aware services. However, a service system should be founded on a context model to ensure reasonable context-awareness, because context information the system needs depends on its target services. Therefore, in this paper, we propose a hierarchical mobile context model for context inference of smart phone users in their daily life. We classify high-level context which can be draw from sensing data into three levels, Context-Behavior-Situation, and define inference methods for each level. With our mobile context model, we can user's meaningful context in his/her daily life besides simple actions or states.

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The Design of User Model for Context-Aware Service in Ubiquitous Environment (Ubiquitous 환경에서의 Context-Aware Service를 위한 User Model 설계)

  • Park, Jong-Won;Lee, Keung-Hae
    • Proceedings of the Korea Information Processing Society Conference
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    • 2004.05a
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    • pp.845-848
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    • 2004
  • Ubiquitous Computing 환경은 컴퓨터 중심의 환경이 아닌 사용자가 편리성과 효율성이 극대화된 서비스들을 제공 받을 수 있는 사용자 중심의 환경이다. 이러한 환경에서 사용자들은 자신의 정보가 언제 어디서 사용되고 있고 어떠한 목적으로 유출되고 있는지 알기 어렵다. 따라서 사용자를 식별하고 개인의 특성에 따라 관련된 서비스를 제공하는데 있어 사용자의 필요정보를 적절하게 보호할 수 있는 메커니즘이 필요하다. 본 논문에서는 Ubiquitous환경에서 특정목적에 국한된 서비스 제공이 아닌 다양한 목적에 따라 서비스가 제공될 수 있도록 사용자의 목적과 상황에 맞는 User Model을 제안하고자 한다. 또한 사용자의 상황에 맞는 Context Content를 구별하여 Privacy등급을 결정하고 사용자마다 독립적이고 안전한 Context-Aware Service를 제공하는 User Model은 사용자마다 정해진 정적 Context와 상황에 따라 변화하는 동적 Context를 모두 고려하여 높은 신뢰성과 안전성을 지닌 방법을 제공한다. 그리고 제안된 User Model의 정의와 시나리오를 설명한다.

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Context-Aware Middleware based on Ontology in Ubiquitous Computing Environment (유비쿼터스 컴퓨팅 환경에서의 온톨로지 기반 상황 인식 미들웨어)

  • Jung Heon-Man
    • KSCI Review
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    • v.14 no.1
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    • pp.165-173
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    • 2006
  • To support service based on context-aware in ubiquitous computing environment, there are required context managing, context reasoning and context modeling technologies. In this paper, we propose a hierarchical ontology-based context management model and design a context-aware middleware based on this model for supporting active application adaptability and reflecting users' requirements dynamically in contextual changes. It also provides efficient support for inferencing, interpreting, acquiring and discovering various contexts to build context-aware services and presents a resolution method for context conflict which is occurred in execution of service. The proposed middleware can support the development and operation of various context-aware services, which are required in the ubiquitous computing environment.

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Development of a Matrix-based Context Awareness Model for Vehicle Environment (자동차 공간을 위한 Matrix기반의 상황인식 모델 개발)

  • Ko, Jae-Jin;Choi, Ki-Ho
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.8 no.6
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    • pp.187-195
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    • 2009
  • Recently, with the development of ubiquitous computing, the study and development about context awareness models is required for the application of ubiquitous environment. This paper presents the design and implementation of a matrix based context awareness model for vehicle environment. The matrix construction method using 5W1H and CAM (Context Awareness Model) expression is proposed for context awareness modeling. The system with the proposed model is implemented by Zigbee modules for the recognition of individual identification and position and a navigator for current spatial and temporal information of GPS. The result of experiments shows that the proposed model is available.

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Recommendation using Service Ontology based Context Awareness Modeling (서비스 온톨로지 기반의 상황인식 모델링을 이용한 추천)

  • Ryu, Joong-Kyung;Chung, Kyung-Yong;Kim, Jong-Hun;Rim, Kee-Wook;Lee, Jung-Hyun
    • The Journal of the Korea Contents Association
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    • v.11 no.2
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    • pp.22-30
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    • 2011
  • In the IT convergence environment changed with not only the quality but also the material abundance, it is the most crucial factor for the strategy of personalized recommendation services to investigate the context information. In this paper, we proposed the recommendation using the service ontology based context awareness modeling. The proposed method establishes a data acquisition model based on the OSGi framework and develops a context information model based on ontology in order to perform the device environment between different kinds of systems. In addition, the context information will be extracted and classified for implementing the recommendation system used for the context information model. This study develops the ontology based context awareness model using the context information and applies it to the recommendation of the collaborative filtering. The context awareness model reflects the information that selects services according to the context using the Naive Bayes classifier and provides it to users. To evaluate the performance of the proposed method, we conducted sample T-tests so as to verify usefulness. This evaluation found that the difference of satisfaction by service was statistically meaningful, and showed high satisfaction.

A Study on Security Model Design of Adaptive Access Control based Context-Aware (상황인식 기반 적응적 접근제어 보안모델 설계에 관한 연구)

  • Kim, Nam-Il;Kim, Chang-Bok
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.8 no.5
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    • pp.211-219
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    • 2008
  • This paper is proposed context-aware based access control, model by extending original access control model. In this paper, we survey the recent researches about security model based context-aware such as xoRBAC and CAAC. For exactly policy evaluation, we make an addition Context Broker and Finder in existing CAAC security model. By this security model, Context information and context decision information is able to be collected easily for more correct policy decision. This paper controlled access of possible every resources that is able to access by user's event and constraint from primitive access resources. In this paper proposed security model can be offer dynamically various security level and access authority method alone with specified policy and constraint adjustment at user's role.

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Implementation of a context-awareness framework and context model for ubiquitous computing environment (유비쿼터스 컴퓨팅 환경을 위한 상황 모델 정의 및 상황 인식 프레임워크 구현)

  • Lee Jung-Eun;Park Hyun-Jung;Park Doo-Kyung;Yoon Tae-Bok;Park Kyo-Hyun;Lee Jee-Hyong
    • Journal of the Korean Institute of Intelligent Systems
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    • v.16 no.4
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    • pp.423-429
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    • 2006
  • The systems in the ubiquitous computing environment need to provide users with context-aware services, intelligently interacting with the surrounding environment. Therefore, the systems in the ubiquitous computing environment require context-awareness ability in order to gather and analyze context information in various situations and environments. However, existing context-aware systems lack the ability to systematically generate and handle various types of context information, and only a few systems have ability learning from environment. In this paper, a general context model is defined to describe various contexts and a context-awareness framework is implemented based in the model, which makes it straightforward to handle and generate various types of context from diverse sensor. The framework is designed to allow a system to sensed, combined, inferred, and learned context information, in order to provide users with services in dynamic environments. We have implemented the proposed framework and applied it to a u-Health management system.

OSGi based Service Middleware for Context-Aware Applications (상황 인식 응용을 위한 OSGi 기반 서비스 미들웨어)

  • Jung, Heon-Man;Lee, Jung-Hyun
    • The KIPS Transactions:PartC
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    • v.13C no.6 s.109
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    • pp.691-700
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    • 2006
  • To support context-aware services in ubiquitous computing environments, there are required dynamic context managing, context reasoning and context modeling technologies. In previous researches, context services are designed using context ontology used in context aware middleware. So, context service cannot change the context ontology in execution time. In this paper, we propose a hierarchical ontology-based context management model and design a context-aware middleware based on this model for supporting active application adaptability and reflecting users' requirements dynamically in contextual changes. It also provides efficient support for inferencing, interpreting, acquiring and discovering various contexts to build context-aware services and presents a resolution method for context conflict which is occurred in execution of service. As the middleware is implemented on the OSGi framework, it can cause interoperability among devices such as computers, PDAs, home appliances and sensors. It can also support the development and operation of context aware services, which are required in the ubiquitous computing environment.

Context Prediction Using Right and Wrong Patterns to Improve Sequential Matching Performance for More Accurate Dynamic Context-Aware Recommendation (보다 정확한 동적 상황인식 추천을 위해 정확 및 오류 패턴을 활용하여 순차적 매칭 성능이 개선된 상황 예측 방법)

  • Kwon, Oh-Byung
    • Asia pacific journal of information systems
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    • v.19 no.3
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    • pp.51-67
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    • 2009
  • Developing an agile recommender system for nomadic users has been regarded as a promising application in mobile and ubiquitous settings. To increase the quality of personalized recommendation in terms of accuracy and elapsed time, estimating future context of the user in a correct way is highly crucial. Traditionally, time series analysis and Makovian process have been adopted for such forecasting. However, these methods are not adequate in predicting context data, only because most of context data are represented as nominal scale. To resolve these limitations, the alignment-prediction algorithm has been suggested for context prediction, especially for future context from the low-level context. Recently, an ontological approach has been proposed for guided context prediction without context history. However, due to variety of context information, acquiring sufficient context prediction knowledge a priori is not easy in most of service domains. Hence, the purpose of this paper is to propose a novel context prediction methodology, which does not require a priori knowledge, and to increase accuracy and decrease elapsed time for service response. To do so, we have newly developed pattern-based context prediction approach. First of ail, a set of individual rules is derived from each context attribute using context history. Then a pattern consisted of results from reasoning individual rules, is developed for pattern learning. If at least one context property matches, say R, then regard the pattern as right. If the pattern is new, add right pattern, set the value of mismatched properties = 0, freq = 1 and w(R, 1). Otherwise, increase the frequency of the matched right pattern by 1 and then set w(R,freq). After finishing training, if the frequency is greater than a threshold value, then save the right pattern in knowledge base. On the other hand, if at least one context property matches, say W, then regard the pattern as wrong. If the pattern is new, modify the result into wrong answer, add right pattern, and set frequency to 1 and w(W, 1). Or, increase the matched wrong pattern's frequency by 1 and then set w(W, freq). After finishing training, if the frequency value is greater than a threshold level, then save the wrong pattern on the knowledge basis. Then, context prediction is performed with combinatorial rules as follows: first, identify current context. Second, find matched patterns from right patterns. If there is no pattern matched, then find a matching pattern from wrong patterns. If a matching pattern is not found, then choose one context property whose predictability is higher than that of any other properties. To show the feasibility of the methodology proposed in this paper, we collected actual context history from the travelers who had visited the largest amusement park in Korea. As a result, 400 context records were collected in 2009. Then we randomly selected 70% of the records as training data. The rest were selected as testing data. To examine the performance of the methodology, prediction accuracy and elapsed time were chosen as measures. We compared the performance with case-based reasoning and voting methods. Through a simulation test, we conclude that our methodology is clearly better than CBR and voting methods in terms of accuracy and elapsed time. This shows that the methodology is relatively valid and scalable. As a second round of the experiment, we compared a full model to a partial model. A full model indicates that right and wrong patterns are used for reasoning the future context. On the other hand, a partial model means that the reasoning is performed only with right patterns, which is generally adopted in the legacy alignment-prediction method. It turned out that a full model is better than a partial model in terms of the accuracy while partial model is better when considering elapsed time. As a last experiment, we took into our consideration potential privacy problems that might arise among the users. To mediate such concern, we excluded such context properties as date of tour and user profiles such as gender and age. The outcome shows that preserving privacy is endurable. Contributions of this paper are as follows: First, academically, we have improved sequential matching methods to predict accuracy and service time by considering individual rules of each context property and learning from wrong patterns. Second, the proposed method is found to be quite effective for privacy preserving applications, which are frequently required by B2C context-aware services; the privacy preserving system applying the proposed method successfully can also decrease elapsed time. Hence, the method is very practical in establishing privacy preserving context-aware services. Our future research issues taking into account some limitations in this paper can be summarized as follows. First, user acceptance or usability will be tested with actual users in order to prove the value of the prototype system. Second, we will apply the proposed method to more general application domains as this paper focused on tourism in amusement park.

An Ontology-based Context Aware Model for the Implementation of Integrated Security Control System (통합보안관제 시스템 구축을 위한 온톨로지 기반의 상황인식 모델)

  • Han, Kwang-Rok;Kim, Jeong-Bin;Sohn, Surg-Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.6
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    • pp.2246-2255
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    • 2010
  • In this paper, we describe an ontology-based context aware model that collects context information from USN sensor and CCTV image and reasons about context in order to development an integrated security control system in the industrial environments. The context model represents autonomous and heterogeneous data as ontologies and recognizes the context through DL(description logic) inference in the smart computing environment. We expect that the integrated security control system can automatically detects the risk in the industrial field and reduces the safety and security incidents by applying this context model to the system.