• IEIE Transactions on Smart Processing and Computing
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• v.3 no.4
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• pp.173-180
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• 2014

Random access protocols feature inherent sensing functionality and distributed coordination, making them suitable for cognitive radio communication environments, where secondary users must detect the white space of the primary spectrum and utilize the idle primary spectrum efficiently without centralized control. These characteristics have led to the adoption of carrier-sensing-multiple-access/collision-avoidance (CSMA/CA) in cognitive radio. This paper proposes a new analytical framework for evaluating the performance of a CSMA/CA protocol that considers the characteristics of idle periods based on the primary traffic behavior in cognitive radio systems. In particular, the CSMA/CA-based secondary network was analyzed in the terms of idle period utilization, which is the average effective data transmission time portion in an idle period. The use of the idle period was maximized by taking its statistical features into consideration.

• International Journal of Advanced Culture Technology
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• v.1 no.2
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• pp.7-12
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• 2013

Mobility management is an important issue in Mobile Ad Hoc Networks (MANETs) because location information of mobile nodes is frequently changed and it aggravates the performance in MANETs drastically. In this paper, we propose a fuzzy logic based mobility management scheme using group quorum system by considering the mobile nodes' locality in order to manage location information of mobile nodes in MANETs efficiently. The proposed scheme selects mobility databases adaptively from group quorum system by considering the degree of locality of a mobile node. The performance of the proposed scheme is evaluated by an analytical model and compared with that of existing mobility management scheme.

• International Journal of Advanced Culture Technology
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• v.1 no.1
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• pp.11-14
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• 2013

In this paper, we propose a prototype of the SpeechWeb application using the information selection agent. We describe its design and implementation method and illustrated the processing results with the aid of some screenshots. Proposed SpeechWeb application presents the associated contents to the user by the aid of dynamic voice-anchors. These contents are presented using the apriori algorithm, which is one of data mining techniques. The application is better than the existing user-initiative structure from the viewpoint of making the user's interesting induction. Moreover, we believe that our proposed application is effective in information retrieval through wired and wireless telephone networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.4
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• pp.1889-1910
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• 2017

This paper investigates a protocol so-called Adaptive Harvest Then Transmit (AHTT) for wireless powered communication networks (WPCNs) in multiple-input single-output (MISO) downlink systems, which assists in transmitting signals from a multi-antenna transmitter to a single-antenna receiver. Particularly, the power constrained relay is supplied with power by utilizing radio frequency (RF) signals from the source. In order to take advantage of multiple antennas, two different linear processing schemes, including Maximum Ratio Combining (MRC) and Selection Combination (SC) are studied. The system outage capacity and ergodic capacity are evaluated for performance analysis. Furthermore, the optimal power allocation is also considered. Our numerical and simulation results prove that the implementation of multiple antennas helps boost the energy harvesting capability. Therefore, this paper puts forward a new way to the energy efficiency (EE) enhancement, which contributes to better system performance.

• Child Health Nursing Research
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• v.15 no.2
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• pp.210-218
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• 2009

Purpose: The existing web sites for premature babies are operated by non professionals and thus do not provide any medical or professional information necessary for rearing premature babies. The purpose is to construct a new website with lots of medical and professional tips for premature babies. Methods: First, topics of discussions are collected from the bulletin boards of three websites, operated by non professionals, for premature babies. And new website for premature babies is constructed based on the identified topics and also based on professional consultation with six professors. Results: The newly constructed website provides professional tips for the above topics as well as introduction of it's object, general medical information and baby rearing information and the bulletin board for parents of premature babies. Conclusion: By providing professional tips for mothers of premature babies, the new website is expected to provide detailed, accurate and professional information on issues most parents of premature babies concern.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.4
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• pp.509-518
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• 1993

Protocol conversion is to resolve the imcompatibility between networks so that users on different protocols can communicate with each other. This paper designs a formal model, EPN , to increase its modeling power and analyze conversion protocol and proposes a conversion algorithm using it. The conversion algorithm has two capabilities : synchronization and automatic error recovery function. Therefore burden of protocol converter design will be reduced, automatic protocol converter design can be possible and implementation for half-gateway will be easy.

• International journal of advanced smart convergence
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• v.5 no.1
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• pp.30-33
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• 2016

With the advent of big data, data mining is more increasingly utilized in various decision-making fields by extracting hidden and meaningful information from large amounts of data. Even as exponential increase of the request of unrevealing the hidden meaning behind data, it becomes more and more important to decide to select which data mining algorithm and how to use it. There are several mainly used data mining algorithms in biology and clinics highlighted; Logistic regression, Neural networks, Supportvector machine, and variety of statistical techniques. In this paper it is attempted to compare the classification performance of an exemplary algorithm J48 and REPTree of ML algorithms. It is confirmed that more accurate classification algorithm is provided by the performance comparison results. More accurate prediction is possible with the algorithm for the goal of experiment. Based on this, it is expected to be relatively difficult visually detailed classification and distinction.

• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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• pp.382-385
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• 2004

In this paper, a new clustering algorithm using the Guaranteed Distance is proposed. In the new algorithm, the appropriate distribution of clusterheads is accomplished by guarantee the stochastic average distance between clusterhead (CH)s. Using this algorithm, the communication cost from clusterheads to their member nodes and the load variance in each clusterheads are reduced. Therefore, the network lifetime can be extended and the fair energy consumption for all nodes can be achieved.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.448-453
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• 2003

Use of wireless LAN limited to special fields in restricted space as enterprises and university networks becomes gradually generalized and its needs are gathering strength. This paper shows transfer modes and structures of 2.400 wireless LAN spreaded at present. And we made experiments on an influence of transmission characteristics and rates of Packet signals in various User's environments and analyzed optimum transmission levels of signals fitted in User's environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.417-422
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• 2003

Ad Hoc network not only can be the constitution of multiple piconet, but also can be the extension to the scatternet. By changing the length of the packets, it will transmit packets according to the amount of the transmission. There are two forms of the bluetooth. The one is the DM which is slower in speed but higher in reliance than the DH. The other is the DH which is faster in speed but lower in reliance than the DM. This paper tries to compare and analyze the performances of mobile hosts according to the forms of the packets in bluetooth Ad Hoc network.