• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.263-266
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• 2013

The universal cloud computing environment, the increase of mobile devices, and the emergence of various web-based services require large amounts of storage space. With the widespread use of Web-based storage services, such as Google Drive, Naver Ndrive, Daum Cloud, there is a need for more storage space. Therefore, storage areas can be provided according to the needs of users of virtualized storage resources through a network, and a large, easy to extend, and royalty in a specific geographical location, cloud storage may be the limelight. In this paper, find out about the features of open source software technology, Hadoop, Swift, GlusterFS for Cloud Storage infrastructure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.482-485
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• 2007

Recent generation of wireless computing has focus on the integrating of exisitng technologies to enhance the mobile capabilities and developing a new approaches to meet the needs of the growing pool of applications. This paper describes an integrated IEEE802.15.4 wireless CDMA based healthcare system that interacts and received the data wirelessly from wireless medical devices of patient and forward to medical center by using the cellular network. Mobile application had been developed not only as the middle ware to handle the receive and transmit of medical data between wireless sensor network and cellular network but also provides the interface for monitoring and analyzing the health condition of patients continuously at cellular phone regardless of its physical location. This system thus enables the remote healthcare monitoring and supports medical data seamlessly roams between IEEE802.15.4 wireless network and CDMA network beyond and outside the hospital environment.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.11_12
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• pp.654-662
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• 2005

Mobile portable devices for wireless network solely depend on a limited battery power. Therefore, we need to design for wireless communication protocols with an energy efficiency. TCP-Westwood is one of the most important approaches on TCP performance improvement in wireless environments that estimates the available bandwidth by using the sampling mechanism. The advantage is that data can be transmitted efficiently using the estimation of available bandwidth. However, when the sender with TCP-Westwood is in a wireless environment, it does not consider of the sampling mechanism operation. In this thesis, a new energy saving transport protocol, called E2TP(Energy Efficient Transport Protocol), is proposed to solve problems which occur when the sender with TCP-Westwood is in a wireless environment. Also, when there are packet loss while doing frequent link error in a wireless environment, E2TP provides the instantaneous segment size adjustment for a more efficient data retransmission. The simulation result proves that the proposed E2TP has better performance in energy efficiency and throughput than both TCP and TCP-Westwood.

• Journal of KIISE
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• v.42 no.11
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• pp.1430-1440
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• 2015

In contrast with battery-based wireless sensor networks (WSNs), solar-powered WSNs can operate for a longtime assuming that there is no hardware fault. Meanwhile, a mobile sink can save the energy consumption of WSN, but its ineffective movement may incur so much energy waste of not only itself but also an entire network. To solve this problem, many approaches, in which a mobile sink visits only on clustering-head nodes, have been proposed. But, the clustering scheme also has its own problems such as energy imbalance and data instability. In this study, therefore, a cluster-based energy-aware data-sharing scheme (CE-DSS) is proposed to effectively support a mobile sink in a solar-powered WSN. By utilizing the redundant energy efficiently, CE-DSS shares the gathered data among cluster-heads, while minimizing the unexpected black-out time. The simulation results show that CE-DSS increases the data reliability as well as conserves the energy of the mobile sink.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.1
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• pp.35-45
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• 2007

The log data collected from mobile devices contains diverse meaningful and practical personal information. However, this information is usually ignored because of its limitation of memory capacity, computation power and analysis. We propose a novel method that detects landmarks of meaningful information for users by analyzing the log data in distributed modules to overcome the problems of mobile environment. The proposed method adopts Bayesian probabilistic approach to enhance the inference accuracy under the uncertain environments. The new cooperative modularization technique divides Bayesian network into modules to compute efficiently with limited resources. Experiments with artificial data and real data indicate that the result with artificial data is amount to about 84% precision rate and about 76% recall rate, and that including partial matching with real data is about 89% hitting rate.

• The Transactions of the Korea Information Processing Society
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• v.6 no.6
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• pp.1481-1492
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• 1999

As Internet is popularized by the advent of Web concept having characteristics such as open network, user-friendly, and easy-usage, there are many changes in Information systems providing various information. Web is rapidly transferred traditional Information systems to Web-based Information systems, because it provides not only text information but also multimedia information including image, audio, video, and etc. Also, as information contents were changed from text-based simple abstract information to full-text information, there was appeared various document formats processing Full-text information. But, as they naturally demand large systems memory, long processing time, broader transmission bandwidth, and etc, estimating of these factors is necessary when constructing information systems. This paper focuses on how to design and construct information system processing full-text information and providing function of an integrated document. Primarily, we should review standard document format which is used or developed, and any document format is appropriate to process full-text information in review with viewpoint of information system. Also, practically we should construct information system providing full-text information based on PDF document.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.4
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• pp.266-278
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• 2013

In this paper, to manage the efficient control of IP packet flows crossing multi-provider networks such as Internet, we propose a SDN(Software Defined Networking)-based policy controller. The proposed policy controller leverages the visibility of underlying network and manages both virtual links and ports to inter-connect networking elements. The controller is capable of quickly composing multiple on-demand virtual networks and dynamically managing the composed networks, thus it can provide more flexible and optimized overlay networking environment to end-user applications. More specifically, we first look into the proposed structure and features of policy controller. With two kinds of service applications, we then verify the applicability of the proposed controller by evaluating its service composition time.

• 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 Korea Computer Industry Society
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• v.3 no.2
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• pp.209-216
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• 2002

World Wide Web has potential possibility of infrastructure for parallel computing environment connecting massive computing resources, not just platform to provide and share information via browser. The approach of Web-based parallel computing has many advantages of the ease of accessibility, scalability, cost-effectiveness, and utilization of existing networks. Applet has the possibility of decomposing the independent/parallel task, moving over network, and executing in computers connected in Web, but it lacks in the flexibility due to strict security semantic model. Therefore, in this paper, Web-based parallel computing environment using mobile agent, Aglet (Agile applet) was designed and possible implementation technologies and architecture were analyzed. And simple simulation and analysis was done compared with applet-based approach.

• Journal of Gifted/Talented Education
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• v.24 no.2
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• pp.243-269
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• 2014

The purpose of this study was to offer suggestions for students, teachers, and parents, respectively, to develop effective gifted education programs in Korea by examining the programs from Vanderbilt Programs for Talented Youth (PTY) at Tennessee in the USA. The method is based on the analyses of PTY web pages, recent materials on programs from PTY, interviews with the executive director of PTY, participation in the endorsement program, and observation in SAVY(Saturday Academy at Vanderbilt for the Young) program. In order to improve gifted education programs in Korea, the results indicate as follows: in respect to students, early identification and education, interdisciplinary humanities curriculums, integrated curriculum models, and information of individual learning plans are essential; in regards to teachers, tailored gifted teacher programs and gifted endorsement programs are necessary; in consideration of parents, programs for supporting parents' groups with professional gifted educators are indispensible.