• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.123-126
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• 2016

Energy efficiency in heterogeneous network is considered as one of the main issues when deploying the wireless sensor network. In heterogeneous network, the random distribution of initial energy at each node could lead to an instability of the network. Therefore, a resonable policy must be established in order to maintain the fairness in energy consumption and extend the working time of each node in the network. In this paper, we evaluate the performance of the distributed clustering protocol (DCP) in heterogeneous network on different scenarios. Simulation results are compared with the results of a LEACH protocol in a heterogeneous network. In addition, the performance of system in heterogeneous network are also compared with the homogeneous network to illustrate the effect of imbalance in the initial energy on the life time of each node in the system. The result illustrates that the DCP protocol demonstrates better performance than LEACH protocol in both the heterogeneous and the homogeneous networks.

• Journal of Korean Clinical Nursing Research
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• v.22 no.1
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• pp.1-9
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• 2016

Purpose: This study was done to identify effects of oral care protocol on oral mucositis and oral care performance in hematologic malignancy patients receiving chemotherapy. Methods: The design of this study was a nonequivalent control group pretest-posttest design. Both groups were patients diagnosed with hematologic malignancies who were receiving chemotherapy-each group had 20 patients. In the experimental group, patients were given intensive education on oral care based on the oral care protocol, whereas in the controlled group, each patient was given an educational brochure. Before chemotherapy, and 3 days, 7 days, and 14 days after chemotherapy, oral mucositis status of two groups were assessed using the guide to physical assessment of the oral cavity. Oral care performance was examined before chemotherapy and 14 days later. Results: The experimental group with the oral care protocol showed a significant difference (F=18.15, p<.001) in the oral mucositis status, and also in oral care performance (t=-10.33, p<.001). Conclusion: Findings indicate that the application of the oral care protocol is an effective tool for lowering the occurrence of oral mucositis and enhancing oral care performance in hematologic malignancy patients receiving chemotherapy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.7
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• pp.1256-1271
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• 1994

In this paper a GFC protocol based on HMR(High-speed Multimedia Ring) with a dynamic quota allocation is proposed and the performance of proposed protocol is evaluated by simulation. The HMR a medium access protocol proposed for Gbit ATM-LAN, can be applied to the GFC protocol without any modification because it uses only 4 bits for medium access of several topologies such as bus, ring and stared-bus, and priority control for satisfaction of different QoS(Quality of Service) requirements. The quota allocation method of HMR called static quota allocation has a problem of excessive access delay for the traffic with high burstness. In this paper a dynamic quota allocation method which allocates quota to the nodes according to the queue length is proposed and the performance of HMR with dynamic quota allocation is evaluated by seven simulation scenarios of CCITT. The HMR with proposed method shows better shows better access delay characteristics than the HMR with static quota allocation. Also the simulation results show that access delay performance of HMR is better than that of ATMR proposed by Japan and is similar to that of DQDB proposed by Australia.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12B
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• pp.1656-1664
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• 2001

When a packet loss occurs in a communication network operating a TCP protocol, the TCP protocol regards it that the loss has resulted from network congestion. Then the TCP protocol performs congestion control. When it is applied to the wireless network having quite a high BER characteristics, the performance of TCP protocol is degraded very much. In this paper, we propose an Explicit Error Notification(EEN) algorithm to improve the performance of the wireless TCP When a packet loss occurs in the wireless network, the TCP receiver decodes the TCP segment sequence number and the address of the TCP sender and receiver, and then informs the TCP sender of the error in wireless network by sending a NACK. It is to distinguish packets in error from losses of network congestion. In this paper, the performance of the proposed EEN algorithm is analyzed and simulated. In fact, as more errors are corrected, the proposed algorithm shows a larger improvements in performance.

• Journal of the Korea Society of Computer and Information
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• v.15 no.2
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• pp.99-107
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• 2010

SNMP(Simple Network Management Protocol) is most commonly used as a standard protocol for effective network management by supporting the increasing size of the network and the variety of network elements such as router, switch, server and so on. However, SNMP has performance drawbacks of network overhead, processing latency, and the inefficiency in data retrieval. In this paper, we propose two schemes to improve the performance of SNMP; 1) the first scheme to reduce the amount of redundant OID information within a SNMP-GetBulk response message, 2) the second scheme of newly proposed SNMP-GetUpdate message combined with the cache in MNS. Through the analysis with real experiments, we show that our first scheme reduces the network overhead and the second scheme improves the processing latency and the retrieval of SNMP MB tables. And, therefore the scalability of network management can be improved.

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.153-158
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• 2008

The technology of Software Defined Radio (SDR) is a possible solution to interwork flexibly between various wireless transport protocols. Ubiquitous network, like u-health service network, includes sensor devices or nodes which do not facilitate all the same transport protocols to access network. As such this may be in such unreachable situations as poverty of all required AP (Access Point)’s, faults or contention in a path of particular protocol communication, etc. This paper presents research results of modeling and simulation to analyze transport performance of multi-protocol ubiquitous network which includes SDR-based interwork nodes and congestion-controlled AP’s. Focusing mainly on dynamics of overall transport performance rather than protocol execution procedures, this paper employs the Zeigler’s DEVS (Discrete Event Systems Specification) methodology and DEVSim++simulation environment to experiment.

• 대한공업교육학회지
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• v.33 no.1
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• pp.233-248
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• 2008

Stream Control Transmission Protocol(SCTP) is a new transport protocol that is known to provide improved performance than Transmission Control Protocol(TCP) in multi-homing environment that is having two and more IP addresses. But currently single-homed computer is used primarily that is having one IP address. To identify whether mean transfer time for SCTP is faster that for TCP in single-homed environment considering packet loss, we make up real testbed regulating the bandwidth, delay time and packet loss rate on router and observe the transfer time. We write server and client applications to measure SCTP and TCP mean transfer time by C language. Analysis of these experimental results from the testbed implementation shows that mean transfer time of SCTP is not better than performance of TCP in single homed environment exceptional case. Main reasons of performance are that SCTP compared to TCP stops transmitting data by timeout and data transmission is often delayed when SACK congestion happens. The result of study shows that elaborate performance tuning is required in developing a new SCTP module or using a implemented SCTP module.

• Journal of the Ergonomics Society of Korea
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• v.29 no.1
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• pp.47-53
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• 2010

An analysis of biosignal and performance data collected during driving has increasingly employed in research to explore a human-vehicle interface design for better safety and comfort. The present study developed a protocol and a system to effectively analyze biosignal and driving performance measurements in various driving conditions. Electrocardiogram (ECG), respiration rate (RR), and skin conductance level (SCL) were selected for biosignal analysis in the study. A data processing and analysis protocol was established based on a comprehensive review of related literature. Then, the established analysis protocol was implemented to a computerized system so that immense data of biosignal and driving performance can be analyzed with ease, efficiency, and effectiveness for an individual and/or a group of individuals of interest. The developed analysis system would be of use to examine the effects of driving conditions to cognitive workload and driving performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.1
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• pp.58-65
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• 2016

Satellite communication is a wide area network (WAN) which provides communication service worldwide. However, the performance of TCP can be seriously degraded in the satellite networks due to limited bandwidth, long round-trip time (RTT) and high bit error rate (BER) over satellite links. In order to improve the performance of TCP, this paper proposes cross-layer Performance Enhancing Proxy (PEP) in digital video broadcasting-return channel via satellite (DVB-RCS) networks. The proposed protocol sets TCP Congestion Window (CWND) size by using satellite resource allocation information exchanged between TCP and the link-layer. we implement PEP testbed based on Linux to evaluate the performance of the proposed protocol. The simulation results show that the proposed protocol performs better than standard TCP both in single and multiple sessions in variant BER, because the proposed protocol sets TCP CWND size by using satellite resource allocation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.7
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• pp.1230-1251
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• 2011

This document specifies a new IPv6 deployment protocol called CHANC, which stands for Configuring Hosts to Auto-detect (IPv6, IPv6-in-IPv4, or IPv4) Network Connectivity. The main part is an application level tunneling protocol that allows Internet Service Providers (ISPs) to rapidly start deploying IPv6 service to their subscribers whom connected to the Internet via IPv4-only access networks. It carries IPv6 packets over HTTP protocol to be transmitted across IPv4-only network infrastructure. The key aspects of this protocol are: offers IPv6 connectivity via IPv4-only access networks, stateless operation, economical solution, assures most firewall traversal, and requires simple installation and automatic configuration at customers' hosts. All data packets and routing information of the IPv6 protocol will be carried over the IPv4 network infrastructure. A simple application and a pseudo network driver must be installed at the end-user's hosts to make them able to work with this protocol. Such hosts will be able to auto-detect the ISP available connectivity in the following precedence: native IPv6, IPv6-in-IPv4, or no IPv6 connectivity. Because the protocol does not require changing or upgrading customer edges, a minimal cost in the deployment to IPv6 service should be expected. The simulation analysis showed that the performance of CHANC is pretty near to those of native IPv6, 6rd, and IPv4 protocols. Also, the performance of CHANC is much better than that of D6across4 protocol.