• Proceedings of the Korean Information Science Society Conference
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• 2006.10c
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• pp.597-600
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• 2006

기존의 상황 인식 서비스 인프라에서는 리소스에 대한 접근 권한을 사용자의 기본 인증으로만 접근을 허용하였다. 그러나 주변 상황 정보가 빈번하게 바뀌는 유비쿼터스 환경에서는 사용자의 권한이 주변 상황에 따라 달라질 수가 있다. 본 논문에서는 사용자의 상황 정보가 변경되는 경우에 따라 리소스에 대한 접근을 제어하고자 한다. 접근 제어 기법으로는 기존의 CASA에서의 상황 정보에 적용되는 요소인 사용자의 주위 환경 정보에 몇몇 상황 정보를 더 추가하여 리소스에 대한 접근을 사용자의 주변 환경 정보에 따라 제어하고자 한다. 기존의 CASA에서의 상황 정보에 서비스를 받고 있는 장소의 주위 환경 정보를 추가하였고, 권한을 가진 사용자에게도 여러 상황 정보에 따라 리소스 접근을 통제한다.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.85-88
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• 2011

모바일 환경으로 업무 환경이 변화함에 따라 발생할 수 있는 요구사항인 탈 사무실화, 기기의 다양성, 실시간성을 만족하면서 보안성을 유지하기 위해 context aware RBAC 모델이 적용되고 있다. 하지만 기존의 상황인식 역할기반 접근제어 모델은 주변 사용자에 대한 고려가 없고 사용자의 단독적인 정보 유출이 가능하다는 단점을 가지고 있다. 이를 해결하기 위해 본 연구에서 제안하고 있는 사용자간의 관계를 고려한 상황인식 역할기반 접근제어 모델에서는 기존의 기법에서 고려하지 않은 주변 사용자의 역할 및 관련된 사용자와의 관계를 고려하여 위치와 시간만으로 제어되지 않는 정보에 대한 유출을 방지한다. 이 모델을 적용할 경우 주변사용자의 권한에 의해 사용자의 권한이 통제되므로 문서에 대한 내부자의 편법적인 사용을 방지하는 것이 가능하고 실시간으로 문서에 대한 권한을 부여할 수 있다. 또한 문서에 대한 권한을 모두 부여할 경우와 동일한 업무 효율성을 가지면서 필요하지 않은 시간에 발생할 수 있는 보안 위협을 방지할 수 있다.

• The KIPS Transactions:PartB
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• v.13B no.5 s.108
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• pp.507-514
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• 2006

Various application systems are developed using RFID as a part of ubiquitous computing, and it is expected that RFID chip will become wide-spread for the distribution industry especially. Efficient and efact intelligent-type of warehouse management system is essential for small-to-medium-sized enterprises in the situation having a trouble in the viewpoint of expense and manpower. In this paper, we implement small-scale warehouse management system using log-based context awareness technology. This system is implemented to be controlled on web, configuring clients to control RFID readers and building up DBMS system in a server. Especially, it grasps user's intention of storing or delivering based on toE data for the history of user's access to the system and it reports user's irregular pattern of warehouse use and serves predictive information of the control of goods in stock. As a result, the proposed system can contribute to enhance efficiency and correctness of small-scale warehouse management.

• Journal of Communications and Networks
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• v.2 no.1
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• pp.18-34
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• 2000

The evolution of mobile communications is inducting several new issues belonging to the system engineering disciplines. this paper tires to underline some of the most important problems staring room the novel requirements and the application characteristics expected for Third Generation Mobile System. Based on these new service peculiarities. the radio resource control and the architectural solutions to be chosen for the Mobile core network are becoming key issues to be investigated for the forthcoming configurations. Particularly. the service acceptance control and the perspective of integration with the IP (internet Protocol) context are of great importance for the definition of the radio control functions and the specification of the switching and nobility control features respectively．The paper presents some basic considerations on the cellular planning issues arising in W-CDMA ( wideband -code division Multiple access) systems. by underlying the most significant innovative elements that are to be introduced in the planning process form the mobile operator viewpoint..

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.744-751
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• 2008

Ubiquitous computing is a new paradigm of telecommunication technology and is embedded with advanced computing technology to process a large amount of data in a normal environment. Generally, ail equipment is embedded with sensors and operating devices to interaction with communication functions. That is why ubiquitous computing must be able to access any devices anywhere at anytime in order to perform appropriate functions. Unfortunately, however, it is difficult to make an optimized design for applications which can effectively interaction with various functions in distributed environment like ubiquitous computing. Therefore, this paper is aimed at deploying interface with server nodules and virtual prototyping by utilizing LabVIEW and embedded application software with additional network function. In addition, given information about sensors collected from context-awareness and location-awareness, it will suggest the ideal ubiquitous application based on context-awareness and apply the advanced application to device control and monitoring through context awareness of lab.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.2
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• pp.221-226
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• 2010

Ubiquitous computing is technology that provides services appropriate for the user. At places where environmental and situational context are relevant in making the determination of what services are appropriate, there are sensor nodes installed, which automatically collect, manage and control environmental information. In this computing environment, in order to meet the requirements of services provided to users, a context awareness system is needed for context awareness processing. In this thesis, using RFID/USN sensors, the context of a user entering and leaving an area was produced, and the user's identification information was received via the RFID reader and antenna. At the same time, to decide whether or not to allow access for the user, a distance sensor node was installed to collect context data. Based on this, a system that provides practical services needed in real life for users was designed and implemented. The context of a user entering an area was produced, which the system recognized and provided appropriate services for the user.

• Convergence Security Journal
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• v.11 no.4
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• pp.77-83
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• 2011

In addition to the rapid development of health information technology services for the development of new medical information, a lot of research is underway. Improve health care services for patients are many ways to help them. However, no information about the security, if only the technology advances in health care systems will create an element of risk and threat. Today's issues and access issues are stable over a public network. Ad hocsensor network using secure, non-integrated health information system's security vulnerabilities does not solve the security vulnerabilities. In the development and utilization of health information systems to be subject to greater restrictions. Different security policies in an environment with a medical information system security policy mechanism that can be resolved if people get here are needed. Context-aware and flexible policy of integration and confidential medical information through the resistance should be guaranteed. Other cross-domain access control policy for telecommunications should be protected. In this paper, that the caller's medical information system, diversification, diversification Security agent in the environment, architecture, design, plan, role-based security system are proposed. The proposed system architecture, design work in the field and in the utilization of one model are expected to be.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.3
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• pp.248-253
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• 2008

This paper presents a sensing system for smart home which can detect an location transition events such as entrance/exit of a member and identify the user in a group at the same time. The proposed system is compose of two sub-systems; a wireless sensor network system and a database server system. The wireless sensing system is designed as a star network where each of sensing modules with ultrasonic sensors and a Bluetooth RF module connect to a central receiver called Bluetooth access point. We propose a method to discriminate a user by measuring the height of the user. The differences in the height of users is a key feature for discrimination. At the same time, the each sensing module can recognize whether the user goes into or out a room by using two ultrasonic sensors. The server subsystem is a sort of data logging system which read the detected event from the access point and then write it into a database system. The database system could provide the location transition information to wide range of context-aware applications for smart home easily and conveniently. We evaluate the developed method with experiments for three subjects in a family with the installation of the developed system into a real house.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7A
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• pp.700-709
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• 2007

The heterogeneous wireless access networks has been envisioned to characterize the future wireless networks. In such environments, TCP(Transmission Control Protocol) has to experience poor end-to-end performance because bandwidth and link delay change suddenly when a mobile node moves over different types of wireless networks, which is called vertical handoff. In this paper, we propose a new TCP which maintains each set of congestion control variables, which we call TCP context, for each type of wireless network. The proposed TCP can switch the TCP context against vertical handoff in order to adjust quickly to a newly arrived network. In simulations, the proposed TCP has higher throughput than TCP SACK(Selective Acknowledgment Options) due to its great features to vertical handoff situations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4754-4773
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• 2018

In sensor medium access control (SMAC) protocol, sensor nodes can only access the channel in the scheduling and listening period. However, this fixed working method may generate data latency and high conflict. To solve those problems, scheduling duty in the original SMAC protocol is divided into multiple small scheduling duties (micro duty MD). By applying different micro-dispersed contention channel, sensor nodes can reduce the collision probability of the data and thereby save energy. Based on the given micro-duty, this paper presents an adaptive duty cycle (DC) and back-off algorithm, aiming at detecting the fixed duty cycle in SMAC protocol. According to the given buffer queue length, sensor nodes dynamically change the duty cycle. In the context of low duty cycle and low flow, fair binary exponential back-off (F-BEB) algorithm is applied to reduce data latency. In the context of high duty cycle and high flow, capture avoidance binary exponential back-off (CA-BEB) algorithm is used to further reduce the conflict probability for saving energy consumption. Based on the above two contexts, we propose an improved SMAC protocol, micro duty adaptive SMAC protocol (MDA-SMAC). Comparing the performance between MDA-SMAC protocol and SMAC protocol on the NS-2 simulation platform, the results show that, MDA-SMAC protocol performs better in terms of energy consumption, latency and effective throughput than SMAC protocol, especially in the condition of more crowded network traffic and more sensor nodes.