• KSII Transactions on Internet and Information Systems (TIIS)
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• 제3권3호
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• pp.219-234
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• 2009

This paper presents a novel approach for extracting simultaneously human daily activity patterns and discovering the temporal relations of these activity patterns. It is necessary to resolve the services conflict and to satisfy a user who wants to use multiple services. To extract the simultaneous activity patterns, context has been collected from physical sensors and electronic devices. In addition, a context model is organized by the proposed incremental statistical method to determine conflicts and to infer user intentions through analyzing the daily human activity patterns. The context model is represented by the sets of the simultaneous activity patterns and the temporal relations between the sets. To evaluate the method, experiments are carried out on a test-bed called the Ubiquitous Smart Space. Furthermore, the user-intention simulator based on the simultaneous activity patterns and the temporal relations from the results of the inferred intention is demonstrated.

• 한국컴퓨터정보학회논문지
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• 제22권7호
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• pp.17-29
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• 2017

IRecently, researches on the recognition of indoor user situations through various sensors in a smart home environment are under way. In this paper, the case study was conducted to determine the operation of the robot vacuum cleaner by inferring the user 's indoor situation through the operation of home appliances, because the indoor situation greatly affects the operation of home appliances. In order to collect learning data for indoor situation awareness model learning, we received feedbacks from user when there was a mistake about the cleaning situation. In this paper, we propose a semi-supervised learning method using user feedback data. When we receive a user feedback, we search for the labels of unlabeled data that most fit the feedbacks collected through genetic algorithm, and use this data to learn the model. In order to verify the performance of the proposed algorithm, we performed a comparison experiments with other learning algorithms in the same environment and confirmed that the performance of the proposed algorithm is better than the other algorithms.

• 한국정보통신학회논문지
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• 제20권5호
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• pp.1013-1019
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• 2016

본 논문에서는 Delay Tolerant Network(DTN)에서 Markov chain으로 노드의 속성 정보를 분석하여 노드의 이동경로를 예측하는 알고리즘을 제안한다. 기존 DTN에서의 예측기반 라우팅 기법은 노드가 미리 정해진 스케줄에 따라 이동하게 된다. 이러한 네트워크에서는 스케줄을 예측할 수 없는 환경에서 노드의 신뢰성이 낮아지는 문제가 있다. 본 논문에서는 이러한 문제를 극복하기 위해 노드의 속성 정보를 Markov chain을 적용하고 일정 구간에서 시간에 따른 노드의 이동 경로를 예측하는 CMCP(Context-awareness Markov-Chain Prediction)알고리즘을 제안한다. 제안하는 알고리즘은 노드의 속성 정보 중 노드의 속력과 방향성을 근사한 후 Markov chain을 이용하여 제한된 주기와 버퍼의 범위에서 확률전이 매트릭스를 생성하여 노드의 이동 경로를 예측하는 알고리즘이다. 주어진 모의실험 환경에서 노드의 이동 경로 예측을 통해 중계 노드를 선정하여 라우팅 함으로써 메시지 전송 지연 시간이 감소하고 전송률이 증가함 보여주고 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권11호
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• pp.2839-2852
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• 2013

Context-awareness is an essential part of ubiquitous computing, and over the past decade video based activity recognition (VAR) has emerged as an important component to identify user's context for automatic service delivery in context-aware applications. The accuracy of VAR significantly depends on the performance of the employed human body segmentation algorithm. Previous human body segmentation algorithms often engage modeling of the human body that normally requires bulky amount of training data and cannot competently handle changes over time. Recently, active contours have emerged as a successful segmentation technique in still images. In this paper, an active contour model with the integration of Chan Vese (CV) energy and Bhattacharya distance functions are adapted for automatic human body segmentation using depth cameras for VAR. The proposed technique not only outperforms existing segmentation methods in normal scenarios but it is also more robust to noise. Moreover, it is unsupervised, i.e., no prior human body model is needed. The performance of the proposed segmentation technique is compared against conventional CV Active Contour (AC) model using a depth-camera and obtained much better performance over it.

• International Journal of Computer Science & Network Security
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• 제23권7호
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• pp.91-100
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• 2023

Pervasive computing is characterized by a key characteristic that affects the operating environment of services and users. It places more emphasis on dynamic environments where available resources continuously vary without prior knowledge of their availability, while in static environments the services provided to users are determined in advance. At the same time, Cloud computing paradigm introduced flexibility of use according to the user's profile and needs. In this paper, we aimed to provide Context-Aware Transactional Service applications with solutions so that it can be integrated and invoked like any service in the digital ecosystem. Being able to compose is not enough, each service and application must be able to offer a well-defined behavior. This behavior must be controlled to meet the dynamicity and adaptability necessary for the new user's requirements. The motivation in this paper is to offer design patterns that will provide a maximum of automatism in order to guarantee short reaction times and minimal human intervention. Our proposal includes a cloud service model by developing a PaaS service that allows CATS adaptation. A new specification for the validation of CATS model has been also introduced using the ACTA formalism.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2005년도 공동추계학술대회
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• pp.359-368
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• 2005

Personalized reminder systems have to identify the user's current needs dynamically and proactively based on the user's current context. However, need identification methodologies and their feasible architectures for personalized reminder systems have been so far rare. Hence, this paper aims to propose a proactive need awaring mechanism by applying agent, semantic web technologies and RFID-based context subsystem for a personalized reminder system, which is one of the supporting systems for a robust ubiquitous service support environment. Rescorla-Wagner model is adopted as an underlying need awaring theory. We have created a prototype system. called NAMA(Need Aware Muiti-Agent)-RFID. to demonstrate the feasibility of the methodology and of the mobile settings framework that we propose in this paper Moreover, to test if the proposed system works in terms of scalability, a simulation was performed and the results are described.

• 정보과학회 논문지
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• 제43권5호
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• pp.531-540
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• 2016

최근 모바일 환경의 다양한 센서 정보를 이용한 상황인지 서비스가 활발히 연구되고 있다. 본 논문에서는 모바일 및 웨어러블 센서 데이터를 사용해 다양한 맥락에서 나타날 수 있는 사용자의 식사상황을 효과적으로 인식할 수 있는 확률모델을 제안한다. 식사행위와 관련된 상황들을 체계적으로 모델링하기 위해 행위이론의 4가지 행위 요소 및 육하원칙의 5가지 구성 요소들을 모바일 및 웨어러블의 저수준 센서 데이터로 추론 가능한 범위에 맞게 통합하여 인식모델을 구축하고, 트리구조의 베이지안 네트워크 모델링 방식을 사용하여 인식의 경량화를 시도하였다. 제안하는 시스템의 유용성을 입증하기 위하여 1주일간 다양한 배경의 4명 사용자로부터 식사상황 및 일상생활에 대한 383분의 데이터를 수집하였다. 실험결과 기존의 대표적인 분류기들과 비교하여 상대적으로 우수한 인식률(93.21%)이 도출되는 것을 확인하였다. 또한 실제 시나리오를 통한 내부 분석을 수행하여 인식에 사용되는 각 요소들의 유용성을 검증하였다.

• Asian Journal of Business Environment
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• 제12권2호
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• pp.13-28
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• 2022

Purpose: Natural products are becoming gradually popular because of their health - related benefits and consumers' environmental awareness. However, research in this field remains limited, the present study attempts to address this research gap by measuring the influencing levels of the antecedents on natural product brand love. Research design, data and methodology: The study employs S-O-R (Stimulus - Organism - Response) framework together with Innovation Resistance Theory and Dual-Factor Theory to propose the research model, in which health and environmental stimuli influence both of facilitators and inhibitors of internal states or organism, and then shape purchase intention and brand love as consumers' responses. The mixed research method is designed with the application of structural equation model (SEM) to analyze 530 consumers collected by convenience sampling. Results: The results revealed that two chosen stimuli, including health awareness and environmental concern were positively related to both facilitators (natural content and regional products) and inhibitors (image barrier and usage barrier) and these four factors were significantly associated to purchase intention and brand love. Furthermore, purchase intention played the mediating role on the relationship between the four organisms and brand love. Conclusions: The originality of this paper is extend S-O-R theory into natural product context with mediating effects in an emerging economy. The findings make theoretical contribution on consumer behavior and managerial implication.

• 한국항행학회논문지
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• 제12권5호
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• pp.470-482
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• 2008

본 논문에서는 유비쿼터스 환경을 위에 컨텍스트 정보를 이용한 역할기반 접근제어 모델을 제안한다. 컨텍스트 정보를 이용한 접근제어의 기본적인 개념은 어떠한 정보나 객체에 접근할 수 있는 권한을 역할에 배정하여, 사용자를 그 역할에 할당함으로써 정보나 객체에 접근할 수 있는 권한을 획득할 수 있도록 하는 것이다. 그러므로 사용자는 자신에게 할당된 역할과 그 역할이 지니고 있는 권한에 맞는 정보 또는 객체에 접근하게 됨으로써 안전하게 정보나 객체의 이용을 보장할 수 있도록 한다. 본 논문에서 제안하는 모델은 GEO-RBAC 모델에서 부족한 제약 사항을 고찰하여 새로운 제약 조건을 제시하고 다양한 경우에서의 역할 충돌을 고려하였다. 또한 GEO-RBAC 모델에 적합한 위임 모델을 제안하기 위하여, 기존 모델의 장/단점을 분석하고 이를 개선하여 GED-RBAC에 적합한 위임 모델을 제안한다.

• Asia pacific journal of information systems
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• 제15권1호
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• pp.115-133
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• 2005

This study is to develop an information security management model(ISMM) for small and medium sized enterprises(SMEs). Based on extensive literature review, a five-pillar twelve-component reference ISMM is developed. The five pillars of SME's information security are: centralized decision making, ease of management, flexibility, agility and expandability. Twelve components are: scope & organization, security policy, resource assessment, risk assessment, implementation planning, control development, awareness training, monitoring, change management, auditing, maintenance and accident management. Subsequent survey designed and administered to expose experts' perception on the importance of these twelve components revealed that five out of tweleve components require relatively immediate attention than others, especially in SME's context. These five components are: scope and organization, resource assessment, auditing, change management, and incident management. Other seven components are policy, risk assessment, implementation planning, control development, awareness training, monitoring, and maintenance. It seems that resource limitation of SMEs directs their attention to ISMM activities that may not require a lot of resources. On the basis of these findings, a three-phase approach is developed and proposed here as an SME ISMM. Three phases are (1) foundation and promotion, (2) management and expansion, and (3) maturity. Implications of the model are discussed and suggestions are made for further research.