• Journal of Internet Computing and Services
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• v.23 no.5
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• pp.25-31
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• 2022

In ultra dense networks (UDNs), macro user equipments (MUEs) have significant interference from small-cell access points (SAPs) since a number of SAPs are deployed in the coverage of macro base stations of 5G mobile communication systems. In this paper, we propose a dynamic channel assignment scheme to increase the performance of MUEs for the uplink of UDNs even though the number of SAPs is increased. The target of the proposed dynamic channel assignment scheme is that the signal-to-interference and noise ratio (SINR) of MUEs is above a given SINR threshold assigning different subchannels to SUEs from those of MUEs. Simulation results show that the proposed dynamic channel assignment scheme outperforms others in terms of the mean MUE capacity even though the mean SUE capacity is decreased a little lower.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.5
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• pp.19-32
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• 2009

In this paper, we design thin-client framework capable of application sharing & data access on the Internet, and apply related skills, such as X windows system, pseudo server, CODA file system, MPI(Message Passing Interface). We suggest a framework for the thin client to access data produced by working on a server optimally as well as to run server side application, even in the case of network down. Additionally, it needed to reflect all local computing changes to remote server when network is restored. To design thin client framework with these characteristics, in this paper, we apply distributed pseudo server and CODA file system to our framework, also utilize MPI for the purpose of more efficient computing & management. It allows for implementation of network independent computing environment of thin client, also provide scalable application service to numerous user through the elimination of bottleneck on caused by server overload. In this paper, we discuss the implementing method of thin client framework in detail.

• The KIPS Transactions:PartD
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• v.14D no.7
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• pp.707-718
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• 2007

Recently, much studies for providing mobile users with suitable and useful content services, LBS(Location Based Service) corresponding to the change of users' location, are actively going on. First and foremost, this is basically owing to the progress of location management technologies such as GPS, mobile communication technology and the spread of personal devices like PDA and the cellular phones. Besides, the research scope of LBS has been changed from vehicle tracking and navigation services to intelligent and personalized services considering the changing information of conditions or environment where the users' are located. For example, it inputs the information such as heavy traffic, pollution, and accidents. The query languages which effectively search the stored vehicle and environment information have been studied depending on the increase of the information utilization. However, most of existing moving object query languages are not enough to provide a recommendation service for a user, because they can not be tested and evaluated in real world and did not consider changed environment information. In order to retrieve not only a vehicle location and environment condition but also use them, we suggest a moving object query language for recommendation service and implement a moving object query process system for supporting a query language. It can process a nearest neighbor query for recommendation service which considers various attributes such as a vehicle's location and direction, environment information. It can be applied to location based service application which utilizes the recommended factors based on environmental conditions.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.6
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• pp.197-204
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• 2015

Recent changes in health care environment including aging population and prevalence of chronic disease encourage the adoption of new innovative technological solutions including wearable vital sensors, wireless networks, and smart phone. In this paper, we present an effective at-home lifestyle monitoring system that can be used for self-management and health intervention of patient himself in the Management-by-Exception perspectives. We implemented the filtering and queuing algorithms as a preprocessor of monitoring system to enhance efficiency of proposed system, and the effective UX design for self-management of patients themselves. The 94,467 actual clinic data was used to test the efficiency of the proposed system. As as a result, 64.8% of the incoming vital data was identified to be filtered out.

• The KIPS Transactions:PartC
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• v.17C no.5
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• pp.399-406
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• 2010

Many problems are arisen due to the weakness in the security and invasion to privacy by malicious attacker or internal users while various data services are available in ubiquitous network environment. The matter of controlling security for various contents and large capacity of data has appeared as an important issue to solve this problem. The allocation methods of Ito, Saito and Nishizeki based on traditional polynomial require all shares to restore the secret information shared. On the contrary, the secret information can be restored if the shares beyond the threshold value is collected. In addition, it has the effect of distributed DBMS operation which distributes and restores the data, especially the flexibility in realization by using parameters t,v,k in combinatorial design which has regularity in DB server and share selection. This paper discuss the construction of new share allocation method and data distribution/storage management with the application of matrix structure of t-(v,k,1) design for allocating share when using secret sharing in management scheme to solve the matter of allocating share.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2581-2585
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• 2010

In the field of network sense for the Ubiquitous environment, the technology of RFID is a significant part. Due to the real time processing of information and the property of network, RFID has been used in service field such as distribution, administrative control of physical distribution, remote measuring device, and security. instead of currently used bar-code. The management system of port facilities using the current RFID technology has the effects of reducing working hours and improvement in data processing, but it is not proper for human resource allocation since it is dominantly worked for physical resources. In this paper, we designed and implemented personnel control system using RFID of 2.4GHz in port facilities which presents a monitoring system for safety operation and increase of efficiency using RFID in order to overcome the limitations and problems of current port operation management techniques.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.2
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• pp.423-437
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• 2015

The IPv6 which solved the exhaustion problem of IPv4's IP address is going to be used for many kinds of industries. As a result, there are some products which can be connected to other connectable things, it called Internet of Things (IoT). With growing new propagated products including networking, each product can get an IP address of IPv6, which means it is possible that things also have their own IP addresses. Thus, IP address management system is more important and needs tracking and collecting system for unused products with IP addresses. This study suggests new distribution tracking and inventory management system for IoT products, which offers a current location of things and manages stocks in the warehouse with the static IP address and the location-based service.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.520-523
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• 2010

In the field of network sense for the Ubiquitous environment, the technology of RFID is a significant part. Due to the real time processing of information and the property of network, RFID has been used in service field such as distribution, administrative control of physical distribution, remote measuring device, and security, instead of currently used bar-code. The management system of port facilities using the current RFID technology has the effects of reducing working hours and improvement in data processing, but it is not proper for human resource allocation since it is dominantly worked for physical resources. In this paper, we designed and implemented personnel control system using RFID of 2.4GHz in port facilities which presents a monitoring system for safety operation and increase of efficiency using RFID in order to overcome the limitations and problems of current port operation management techniques.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.133-135
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• 2015

This paper is about the design of flowerpot management system which allows you to manage the flowerpot more efficiently and conveniently using Internet of Things when you start to grow plants. IoT connects all things to the network to provide various services to users, it has recently been focused on the center of the IT convergence techniques. So by using the realization sensor based IoT technology the need for research and development of IoT technologies were designed for the system. Basically, Device is using soil humidity sensor and Arduino, Android smart phone and smart light bulb. Transmit the humidity value of the flowerpot that measured by the sensor in a wireless communication, by controlling the state according to the value of the humidity, users can be provided a visual information and set up a flowerpot management and plan.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1078-1087
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• 2014

In the conventional centralized mobility management schemes, it can lead to single points of failure, occurrence of a bottleneck, since all data and control are concentrated on the mobility anchor which is located in home network. In the current research of distributed mobility management, it is doing research into distributed mobility management which is supported by distributed mobility anchors. Such schemes do not consider a failure of the mobility anchor. However, it could be an issue under tactical environment since it occur non-service problem due to anchor movement, maintenance, failure, etc. In this paper, we proposed new DMM scheme named T-DMM(Tactical-Distributed Mobility Management) which can support handover even if mobility anchor breaks down. From the numerical analysis, we evaluate signaling cost and handover latency.