• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.493-506
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• 2008

In this paper we suggest dynamic access control model based on context satisfied with requirement of u-healthcare environment through researching the role based access control model. For the dynamic security domain management, we used a distributed object group framework and context information for dynamic access control used the constructed database. We defined decision rule by knowledge reduction in decision making table, and applied this rule in our model as a rough set theory. We showed the executed results of context based dynamic security service through u-healthcare application which is based on distributed object group framework. As a result, our dynamic access control model provides an appropriate security service according to security domain, more flexible access control in u-healthcare environment.

• Journal of the Korea Society of Computer and Information
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• v.13 no.2
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• pp.79-85
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• 2008

The middleware that provides RFID-based ubiquitous application service should process the data inputted constantly in real time, and acquire and deliver the answers of the questions in the application service. Studies for developing a Data Stream Management System(DSMS) has been performed in order to process a large amount of data stream inputted constantly in this way. Previous algorithms on data stream were mostly focused on reducing the average error between the answers of the successive questions and abandon the data according to the priority of them when a load occurs. This article is composed of presenting the necessity of the studies on the DSMS and speedy data processing, suggesting an algorithm to make Possible the speedy data processing using buffers and prompt questions and answers, and testing the performance of the data processing rate and whether a buffer is generated correspondingly to the algorithm suggested, in either a single or a multiple buffer, through simulations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.763-766
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• 2005

Ubiquitous Computing owes Internet and development of computer network and appeared. RFID (Radio frequency Identification) technology is noted by point technology to realize this. However, PML that present in Auto-lD Center is defined point part to describe information of object, and necessary part is to use defining extension separately in actuality application. So that can define object type that can be used for electron tag data processing in RFID application service because do fetters to Auto-lD Center's PML Core in this treatise hereupon and apply in physical distribution circulation service field, designed object information data model.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.1120-1127
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• 2008

This paper presents implementation of localization system using UWB (Ultra-Wide Band) sensors and its experimental results along with development of context-aware services. In order for precise measurement of position, we experimented various conditions of pitch angles, yaw angles, number of sensors, height of tags along with measuring errors at each installation. As an application examples of the location tracking system, we developed an intelligent health training management system based on context-aware technology. The system provides appropriate training schedule to a trainee by recognizing position of the trainee and current status of gymnastic equipments and note the usage of the equipment through a personal digital assistant (PDA). Error compensation on position data and moving direction of the trainee was necessary for context-aware service. Hence, we proposed an error compensation algorithm using velocity of the trainee. Experimental results showed that proposed algorithm had made error data reduce by 30% comparing with the data without applying the algorithm.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.6
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• pp.104-113
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• 2011

While converging USN Services, a single physical infrastructure can be used in several services and in several physical infrastructures can make up a single service. Therefore the physical infrastructure and service have to manage separately for effective convergence of USN Services. However, established Identification Scheme is not suitable to distinguish various services that USN provides. This paper suggests USN Service Identification Scheme that can be separated and managed. Through USN Service Identification Scheme suggested, firstly, it is possible to obtain Service Identification Scheme utilizing various technology such as RFID TAG, QR Code, radio broadcasting, etc. because it is possible to process USN Service Identification Scheme. Secondly, it is easy to mange the service, develope the user application program and interlock with established USN Standard technique as view from service provider. Thirdly, it is possible to manage systematically USN Service. Fourthly, users can search USN Service easily, so it can contribute actively for invigoration of USN service. This thesis, firstly, has analyzed about standard related USN Service and USN Identification Scheme. Secondly, this has suggested brand-new USN Service Identification Scheme based on established USN Identification Scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.899-902
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• 2009

As computer network and wireless technology continue to grow rapidly, a wide range of remote application has been applied to medical field such as remote medical consulting and remote patient monitoring. This research aims to design RF telecommunication-based healthcare application to collect and manage patient's physiological data, and describe the overall procedure of experiment. MySQL database is designed to record patient's physiological data including temperature, blood pressure and heart rate and save information about medical behaviors such as doctor's prescription for patients. Therefore, users approved by healthcare application can query patient's data and collected data can be used to reorganize data for clinical test. As a result, temperature and humidity of patient's room which must be checked frequently can be processed automatically through ubiquitous sensor network. The information entered from mobile phones or web is saved in database, ensuring systematical management through computer. Moreover, patient's family members can easily access hospital data, improving their experience with medical service.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.131-140
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• 2011

Smart packet agent is an application that is proposed to provide routing protocol and service module in ubiquitous network environment. However, it uses multi-hop broadcast, thus it causes increasing network traffic, low-speed data transmission, and the unnecessary joining nodes. In this paper, a transmit technique that uses unicast-based multi-hop to have lower network traffic and faster transmission time than the multi-hop broadcast technique. In our scheme, u-Zone Master establishes temporary routing paths by calculating moving nodes' hop-counter. Therefore, it reduces smart packet agent's network traffic and retransmission rate. Besides, this paper proposed an UDP transmission that bases on sliding window. Hence, the Stop & Wait transmission speed is improved. The results, which are taken by analyzing performance prove that the proposed scheme has better performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.453-456
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• 2007

In this paper, we describes a design of Wireless Mesh Network based middleware that applied into USN(Ubiquitous Sensor Networks). WMN based middleware is a technique which links data between widely distributed sensor devices and WMN for context-awareness. The use of WMN base middleware in this paper makes possible communication on insufficiently network constructed area by use of WMN. WMN based middleware also anaylze events comprehensively that originated from specific sensor device. Based on the result from analyzed data with predetermined value WMN based middleware will given an order to designated actuator devices. Middleware operate each function of sensor network management and application service separately.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.4
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• pp.352-362
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• 2008

In the mobile ad hoc network, network nodes are continuously capable of movement, but have battery limitations and these characteristics of MANET cause network link failure. Therefore, when performing ubiquitous services with the application of MANET, a technique is required to improve the packet transmission rates as to enable continuous packet transmission while flexibly adapting to topology changes caused by the mobility of nodes. In this paper, we are proposing PAOMDV(Possibility based AOMDV) and OLSR-ME(OLSR with Modified Energy Efficiency) which are mixed-type protocols to solve the problem for design a more efficient protocol. Especially by classifying mobile ad hoc networks as clusters, OLSR-ME protocol is implemented on communication within the clusters, while PAOMDV is used in protocols between clusters. In addition, a selection algorithm for forwarding nodes that responding packet relays in the case of increased hops was proposed for designing a more efficient protocol than existing protocols. We verified the performance of the proposed protocols through a comparative experiment with AODV, AOMDV, ZRP, and the existing protocols. We confirmed the results of the experiment revealed that the proposed protocol had the best packet transmission rate, the shortest delay between nodes, and showed better results in routing overhead.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.3
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• pp.15-22
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• 2010

Today's rapid shifts toward a new paradigm are combining city spaces with reality and technology, which is known as a ubiquitous environment. An ubiquitous environment means that 'whenever' and 'wherever' become connected. It is a great possibility that this will change our future lifestyle. Korea has the biggest advantage in the implementation of this new environment, such as having an excellent network infrastructure. Using these attributes of a ubiquitous environment, changes are being made toward ubiquitous cities within developing fields of construction, landscaping, streets, art, and the environment. This research is based on background of research that activated media pole in public city space has been done research about reality of digital skill, fusion, and sense of ubitizen, and Kang-Nam U-street applied by ubiquitous technique. While reflecting an environment that can be utilized in a modern digital society, the application of ubiquitous technology to media pole can be a space for the two-way communication of the current paradigm. It would also be meaningful to create a new cultural space through media pole. Through evaluation, citizens of the ubiquitous age are going to interact to raise the satisfaction that media pole in city space can prevent giving direction to develop and trial and error about service ability, identity, and publicity. Finally, the media pole can be used as a fundamental element to suggest directions for change when viewed as future development.