• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.7-16
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• 2012

In this paper we describe a VoIP transcript system which is able to record call conversation between counselor and customer in an IP contact center based on IP telephony environment. The transcript system, designed and implemented in this paper, uses packet sniffering to capture packets without imposing network overhead on overall system. It can decode H.323 and SIP which are used to setup call sessions in VoIP environment and captures voice data and record without any loss of contents. Implemented transcript system can be integrated with CTI system in that it can manage and record call more effectively. It is designed generically so that it is implemented both on Windows and Linux environment.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.7 s.361
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• pp.81-87
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• 2007

While conventional frequency reuse techniques for cellular communication systems divide frequency resources into multiple regions and each mobile is statically assigned to a certain frequency region, frequency reuse techniques for cellular OFDMA communication systems can be regarded as dynamic scheduling problems of finding best-fitted subcarriers for each packet transmission. Unlike conventional frequency reuse techniques allocating mutually exclusive frequency resources to adjacent cells, this paper proposes the use of a frequency reuse technique with irregular frequency allocation patterns assigned statically based on the cell numbers. This paper shows that the use of irregular frequency patterns can allow efficient interference avoidance and high data throughputs comparable to those with carefully planned frequency patterns.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.2
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• pp.115-125
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• 2015

This paper presents a Cuckoo search algorithm to secure adversaries misdirecting multi-hop routing in Mobile ad hoc networks (MANETs) using a robust Trust Predicated Routing Framework with an optimized cluster head selection. The clustering technique designed in this framework leads to efficient routing in MANETs. The heavy work load in the node causes an energy drop in cluster head, which leads to re-clustering of the group, and another cluster head is selected to avoid packet loss during data transmission. The problem in the re-clustering process is that the overall efficiency of the routing process is reduced and the processing time is increased. A Cuckoo search based optimization algorithm is proposed to solve the problem of re-clustering by selecting the secondary cluster head within the initially formed cluster group and eliminating the reclustering process. The proposed framework enables a node to select a reliable and secure route for MANET and the performance can be evaluated by comparing the simulated results with the AODV routing protocol, which shows that the performance of the proposed routing protocol are improved significantly.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.1
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• pp.14-19
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• 2009

In Mobile Ad-hoc Network, link failure and packet loss may occur frequently due to its nature of mobility and limited battery life. In this paper, an enhanced robust routing protocol based on AODV(Ad hoc On-demand Distance Vector routing) by monitoring variation of receiving signal strength is proposed. New metric function that consists of node mobility and hops of path is used for routing decision. For preventing route failure by node movement during data transmission, a new route maintenance is presented. If the node movement is detected, the routing agent switches local path to its neighbor node. Simulation results show that the performance of the proposed routing scheme is superior to previous AODV protocol.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.516-521
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• 2010

In the high-speed packet service, next generation mobile communication system has emerged as a major feature. If the fire of these high-speed D kit services and non-continuous transmission of data due to the symmetrical nature of daeyiteo traffic for D-CDMA system has been actively studied. In this paper, we apply turbo codes for D-CDMA has been investigated. Considering the nature of the system configuration of the transmission frame type, such as physical channel structure and channel coding has been investigated. In addition to TD-CDMA system, one HARQ gibeopjung hase Combining the performance analysis techniques were applied.

• The Journal of Korean Academic Society of Nursing Education
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• v.20 no.4
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• pp.587-595
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• 2014

Purpose: This study undertakes to identify factors influencing the perception university students in Korea hold toward having children. Method: A cross-sectional, descriptive study was conducted on 187 university students (79 males and 108 females) from one university located in a metropolitan area. Participating students completed a packet of self-report questionnaires on values concerning gender roles, marriage, family and children along with their personal demographic details. The resulting data were analyzed using t-tests, one-way ANOVA and Pearson's correlation coefficients as well as descriptive statistics. Stepwise multiple regression was performed to identify factors that most influenced the value of children held among university students. Results: The value of having children was negatively associated with the value of family, but positively associated with the value of marriage. In addition, the value of family had a negative relationship with the value of marriage, but a positive relationship with the value of gender role. Stepwise multiple regression found that the equation consisting of gender and value of marriage explained about 42.0% of the variance of the value of having children. Conclusion: Considering the findings from this study, programs promoting the positive values of marriage are required for university students to have positive values toward having children.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.605-609
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• 2002

Reliable multicast data transmission in a 1:N environment needs more sophisticated error control mechanism than that of in 1:1 environment due to ACK implosion and duplicated retransmission. Although there have been many related research on error control in reliable multicast, real implemented protocols are rare. As one of the reliable multicast transport protocols, ECTP is selected as an international standard reliable multicast protocol by ITU-T and ISO and implemented on RedHat 7.2 machine by us. In this paper, we evaluate the performance of the error control mechanism in the respect of throughput and generated control packet numbers with a real implementation code. From the results, it is concluded that the suitable values of error control parameters can be obtained from the local group size and network environments.

• The Transactions of the Korea Information Processing Society
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• v.3 no.6
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• pp.1386-1396
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• 1996

In the distributed multimedia application, high throughput and low delay is one of the most important QoS(Quality of Service) requirement. Emerging high speed communication offers transmission rate above Gbps, but it can not be utilized efficiently by the performance bottlenecks of communication protocols. To overcom the problem, we propose a horizontal processing architecture that processes data as soon as it arrive from the network. Unfortunately, the OSI protocol stack often imposes ordering constraints that prevent concurrent processing of the protocol layers. By using a fixed packet format, the network layer through the presentation layer are processed in parallel. Our prototype shows that the proposed model has performance improvement up to 61% more advantage than the conventional approach.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7B
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• pp.694-702
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• 2009

Geographical routing protocol, where nodes only need local information exchange to make routing decisions, is a very efficient routing scheme for wireless sensor networks in scalability. However, pure geographical routing does not take account of wireless link condition. If wireless link condition is not considered, when the routing table is updated, the nodes with bad link conditions are updated in the routing table and can be chosen as the next hop. This brings out the retransmissions because of received packet's errors. Also, because of these retransmissions, additional power is consumed. In this paper, we propose geographical routing scheme considering wireless link condition, where reliable data transmission is made and the consumed energy is minimized.

• Journal of Communications and Networks
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• v.16 no.4
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• pp.465-474
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• 2014

Wireless sensor network (WSN) is considered to be one of the most important research fields for ubiquitous healthcare (u-healthcare) applications. Healthcare systems combined with WSNs have only been introduced by several pioneering researchers. However, most researchers collect physiological data from medical nodes located at static locations and transmit them within a limited communication range between a base station and the medical nodes. In these healthcare systems, the network link can be easily broken owing to the movement of the object nodes. To overcome this issue, in this study, the fast link exchange minimum cost forwarding (FLE-MCF) routing protocol is proposed. This protocol allows real-time multi-hop communication in a healthcare system based on WSN. The protocol is designed for a multi-hop sensor network to rapidly restore the network link when it is broken. The performance of the proposed FLE-MCF protocol is compared with that of a modified minimum cost forwarding (MMCF) protocol. The FLE-MCF protocol shows a good packet delivery rate from/to a fast moving object in a WSN. The designed wearable platform utilizes an adaptive linear prediction filter to reduce the motion artifacts in the original electrocardiogram (ECG) signal. Two filter algorithms used for baseline drift removal are evaluated to check whether real-time execution is possible on our wearable platform. The experiment results shows that the ECG signal filtered by adaptive linear prediction filter recovers from the distorted ECG signal efficiently.