• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.406-412
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• 2019

In this paper, we propose two algorithms for classifying services with similar delay characteristics into three classes and allocating radio resources according to priority in LTE-A system where H2H and M2M services coexist. The first is to allocate resources from the higher priority class to the lower priority class, and each class gives priority to H2H over M2M, and the other is to give priority to H2H regardless of delay characteristics except for the class with the highest priority. The RA success probability was analyzed according to the access rate(${\alpha}$) of M2M devices in each class. In comparison with the conventional systems, it was improved from 0.5 to 0.52 for ${\alpha}_{2M}=0.05$ in two classes. In the three classes, the success probability was slightly increased from 0.5 to 0.57 for ${\alpha}_{2M}={\alpha}_{3M}=1$ and from 0.5 to 0.58 for ${\alpha}_{2M}=0.5$ and ${\alpha}_{3M}=0.1$. Although 6 services are considered in the proposed scheme, the RA success probability is almost similar to the previous scheme because the average arrival rate of H2H of each class is set to the same.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.352-360
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• 2019

This paper proposes a docking assessment algorithm for an autonomous underwater vehicles (AUVs) with sensor uncertainties. The proposed algorithm consists of two assessments, state assessment and probability assessment. The state assessment verifies the reachability by comparing forward distance to the docking station with expected distance to reach same depth as the docking station and necessity for correcting its route by comparing calculated inaccessible areas based on turning radius of the AUV to position of the docking station. When the AUV and the docking station is close enough and the state assessment is satisfied, the probability assessment is conducted by computing success probability of docking based on the direction angle, relative position to the docking station, and sensor uncertainties of the AUV. The final output of the algorithm is decided by comparing the success probability to threshold whether to try docking or to correct its route. To verify the validation of the suggested algorithm, the scenario that the AUV approaches to the docking station is implemented through Matlab simulation.

• Knowledge Management Research
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• v.4 no.2
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• pp.95-105
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• 2003

The purpose of the current study is to explore what are critical success factors(CSFs) from Posco Engineering and Construction Company's knowledge management practice. From a deep case study of the company, five CSFs are delineated. The first factor is to clarify knowledge management vision and strategy so that people in the company clearly understand directions of where the company goes to implement knowledge management. The second one is to grip the whole picture of knowledge management realms. Narrow eyes for the knowledge management leads to failure. The third factor depends on how to acquire people's cooperation. The fourth one has something to do with a way of approach. Unilateral or delegated approach is fragile for the successful implementation of knowledge management. Shared approach raises the probability of success. The fifth one is to monitor implementation acts and processes.

• Journal of applied mathematics & informatics
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• v.27 no.5_6
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• pp.1481-1488
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• 2009

A construction of Cartesian authentication codes over unitary geometry is presented and its size parameters are computed. Assuming that the encoding rules are chosen according to a uniform probability distribution, the probabilities of success for different types of attacks are also computed.

• Journal of the Korean Data and Information Science Society
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• v.21 no.6
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• pp.1109-1115
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• 2010

In this paper, exact confidence interval of hyper-geometric parameter, that is the probability of success p in the population is discussed. Usually, binomial distribution is a well known discrete distribution with abundant usage. Hypergeometric distribution frequently replaces a binomial distribution when it is desirable to make allowance for the finiteness of the population size. For example, an application of the hypergeometric distribution arises in describing a probability model for the number of children attacked by an infectious disease, when a fixed number of them are exposed to it. Exact confidence interval estimation of hypergeometric parameter is reviewed. We consider the performance of exact confidence interval estimates of hypergeometric parameter in terms of actual coverage probability by small sample Monte Carlo simulation.

• Journal of Communications and Networks
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• v.15 no.2
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• pp.132-141
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• 2013

In this paper, we present diversity coded orthogonal frequency division multiplexing (DC-OFDM), an approach to maximize the probability of successful reception and increase the reliability of OFDM-based systems through diversity coding. We focus on the application of DC-OFDM to vehicular networks based on IEEE 802.11p technology and analyze the performance improvement using this new technology. It is shown that DC-OFDM significantly improves the performance of vehicular ad hoc networks in terms of throughput and the expected number of correctly received symbols.

• ETRI Journal
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• v.30 no.5
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• pp.663-673
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• 2008

The multi-scenario topology of multi-channel hybrid ubiquitous sensor networks (USNs) is studied and a novel link auto-diversity cross-layer cooperative scheduling scheme is proposed in this paper. The proposed scheme integrates the attributes of the new performance evaluation link auto-diversity air-time metric and the topology space in the given multi-scenario. The proposed scheme is compared with other schemes, and its superiority is demonstrated through simulations. The simulation results show that relative energy consumption, link reception probability, and end-to-end blocking probability are improved. The addressing ratio of success with unchanged parameters and external information can be increased. The network can tolerate more hops to support reliable transportation when the proposed scheme is implemented. Moreover, the scheme can make the network stable. Therefore, the proposed scheme can enhance the average rate performance of the hybrid USN and stabilize the outage probability.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.11
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• pp.5218-5233
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• 2018

The coexisting wireless body area networks (WBAN) is a very challenging issue because of strong inter-networks interference, which seriously affects energy consumption and spectrum utilization ratio. In this paper, we study a power control strategy with nearest neighbor nodes distribution for coexisting WBAN based on stochastic geometry. Using homogeneous Poisson point processes (PPP) model, the relationship between the transmission power and the networks distribution is analytically derived to reduce interference to other devices. The goal of this paper is to increase the transmission success probability and throughput through power control strategy. In addition, we evaluate the area spectral efficiency simultaneously active WBAN in the same channel. Finally, extensive simulations are conducted to evaluate the power control algorithm.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.187-195
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• 2013

In this paper, we propose a transmission power control scheme for performance improvement of VANET using STPC algorithm considering traffic-flow model. In traffic congestion, a transmission power between car and car increases the collision probability of control messages, which causes the problems to decrease the performance of VANET. The proposed scheme is evaluated by OPNet modeler 16.0 for analyzing its performance and effectiveness in terms of end-to-end delays in hops, packet success probability, and throughput. The simulation result show that the proposed scheme reduces a delay in hops and increases high packet transmission success ratio. Furthermore, a throughput under high density traffic is improved effectively.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.3
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• pp.19-26
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• 2012

To resist the relay attacks in RFID system, it is commonly used RFID distance bounding protocols using the round trip time measurement for 1 bit challenge and response between a reader and a tag. If the success probability of relay attacks for the 1 bit challenge and response can be reduced in these protocols, it is possible to make an efficient distance bounding protocol. In this paper, we propose an efficient RFID distance bounding protocol based on 2 bit challenge and response which is modified the RFID distance bounding protocol proposed by Hancke and Khun based on 1 bit challenge and response. The success probability of relay attack for the proposed protocol is (7/16)n for the n times of challenge and response, which is much lower than (3/4)n given by Hancke and Khun's protocol.