• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.6
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• pp.471-478
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• 2013

Powerful error control and increase in the number of bits per symbol should be provided for future high-quality communication systems. Each message bit may have different importance in multimedia data. Hence, UEP(unequal error protection) may be more efficient than EEP(equal error protection) in such cases. And the LDPC(low-density parity-check) code shows near Shannon limit error correcting performance. Therefore, the effect of UEP with LDPC codes is analyzed for high-quality message data in this paper. The relationship among MSE(mean square error), BER(bit error rate) and the number of bits per symbol is analyzed theoretically. Then, total message bits in a symbol are classified into two groups according to importance to prove the relationship by simulation. And the UEP performance is obtained by simulation according to the number of message bits in each group with the constraint of a fixed total code rate and codeword length. As results, the effect of UEP with the LDPC codes is analyzed by MSE according to the number of bits per symbol, the ratio of the message bits, and protection level of the classified groups.

• Journal of the Korea Society of Computer and Information
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• v.17 no.6
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• pp.75-81
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• 2012

This paper has proposed Message Count Control Mechanism based Link State Update(LSU) Algorithm that has not had a strong influence on the depreciation of QoS routing performance. Most existing LSU algorithms have the limit that cannot control the count of LSU message. Especially, adaptive algorithms have a bad performance when traffic are excessive and fickle. We classify as the importance of LSU message that have a influence on available bandwidth and determine the transmission of the message according to update rate per a unit of time. We have evaluated the performance of the proposed model and the existing algorithms on MCI simulation network using the performance metric as the QoS routing blocking rate and the mean update rate per link, it thus appears that we have verified the performance of this algorithm.

• The Research Journal of the Costume Culture
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• v.17 no.5
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• pp.791-806
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• 2009

Internet brand community's message makes significant contributions for fashion industry. Therefore, if we understand and implement the characteristics of the message on the Internet brand's community, it can be useful for future marketing strategy. This study was to classified the internet community and to examine messages with regard to direction, write motive and prior knowledge. The messages were taken from February, 20th, to August, 7th in 2008. Content analysis method was used for this study. The results were as follows: First, Fashion brand community divided into user initiative type and enterprise establishing type. Second, User initiative type had positive direction message more than enterprise establishing type had. Third, User initiative type had large volumes of information searching or sharing related message, but enterprise establishing type had large quantities of personal experience related message about write motive. Fourth, There was no difference numerical prior knowledge between user initiative type and enterprise establishing type, and then both had a high rate of prior knowledge.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.517-522
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• 2011

Global Navagation Satellite System(GNSS) is divided into Local Area Differential GNSS and Wide Area Differential GNSS. Wide Area DGNSS has more complicated structure and massage type. And transfer rate is limited, so efficient message scheduling algorithm is needed to guarantee user's accuracy and integrity. There are about 30 message types in Wide Area DGNSS. Each message type has different update interval. In this paper, the performances of message scheduling algorithm for Wide Area Differential GNSS are investigated. For all message types, results show that max update time interval requirement is satisfied.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.2
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• pp.201-209
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• 2023

Time comparison techniques are required for generating and keeping Coordinated Universal Time (UTC) and to distribute standard clocks. These techniques play an important role in various fields, including science, finance, military, and communication. Among these techniques, Two-Way Satellite Time and Frequency Transfer (TWSTFT) ensures a relatively high accuracy, with a time comparison accuracy at a nanosecond level. However, TWSTFT systems have some limitations, such as the dependency on extra network links. In this paper, we propose an improved method for TWSTFT system operation and design a message structure for the suggestion. Additionally, we estimate the data rate and redundancy for the new TWSTFT signal with the designed message structure.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.10
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• pp.1248-1257
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• 1999

MDDS는 디스크 시스템의 성능을 향상시키기 위해 하이퍼큐브의 각 노드에 디스크 블록들을 분산 저장하며, 인접한 노드에서 분산 저장하고 있는 디스크 블록을 중복 저장하고 있는 디스크 시스템이다. 본 논문에서는 디스크 서비스 시간을 분석하기 위한 선행 연구로서 소스 노드에서 생성된 디스크 서비스 요구 메시지가 디스크 서비스를 제공하는 목적 노드에 수신될 때까지의 시간인 전송 시간을 분석한다. 이러한 메시지의 전송 시간을 분석하기 위해 이 메시지가 링크를 통해 전송되지 못하고 대기할 확률인 전송 대기 확률을 분석한다. 이들 메시지의 전송 대기 확률을 분석하기 위해 메시지가 각 링크에서 전송되지 못하고 대기해야 하는 시간인 전송 대기 시간을 분석한다. 또 디스크 서비스 요구 메시지의 전송을 위해 링크가 사용되는 비를 분석하며, 메시지의 전송 대기 확률, 전송 대기 시간, 메시지 전송을 위해 링크가 사용될 비를 이용하여 디스크 서비스 요구 메시지의 전송 시간을 분석한다. Abstract Mirrored Declustering Disk System(MDDS) is the disk system to enhance the performance of disk system for hypercube. In MDDS, each node stores the disk blocks using the declustering technique. And the node also duplicates the disk blocks stored in neighboring nodes. In this paper, as the leading research for analyzing the disk service time, we analyze the transmission time of the disk service request message from the source node to the destination node. To analyze the transmission time of disk service request message, we analyze the probability of blocking the message related to the disk service request. For the analysis of the blocking probability, we analyze the blocking time at the link. We also analyze the rate at which the transmission link is used for transferring the disk service requests. And we analyze the transmission time of disk service request message by using the blocking probability, the blocking time, and the usage rate of link for transmitting the message.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.12
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• pp.1224-1228
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• 2010

The existing cluster-based routing protocols have some problems. Firstly, because of selecting cluster head at random, they occur a node concentration problem. Secondly, they have a low reliability for data communication due to the less consideration of node communication range. Finally, data communication overhead is greatly increased because of sending all sensor node information to sink node for constructing clusters. To solve these problems, we in this paper, propose a cluster-based routing protocol using message reception success rate. Firstly, to solve the node concentration problem, we design a cluster head selection algorithm based on node connectivity and devise cluster spliting/merging algorithms. Secondly, to guarantee data communication reliability, we use message reception success rate. Finally, to reduce data communication overhead, we use only neighbor nodes information at both cluster construction and cluster head selection.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7248-7258
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• 2014

The study was conducted as a quasi-experimental study targeting 60 patients with ischemic heart disease to determine how the smoking cessation program that uses telephone counseling and text messaging (short message) affects smoking cessation self-efficacy, nicotine dependence, co levels, and smoking cessation rate of the first, second experimental group at varying times of arbitration and control group. An examination of the effects of this program revealed the control group to have a significant increase in smoking cessation self-efficacy, smoking cessation rate than the first and second group but a significant decrease in the nicotine dependence, co levels. In addition, although the control group showed a significant increase in smoking cessation self efficacy, smoking cessation rate and a significant decrease in co levels than other groups, there was no difference in nicotine dependence. Therefore, a smoking cessation program that uses telephone counseling and text messaging (short message) for patients with ischemic heart disease worked for the smoking cessation rate and appeared to be more effective, depending on the times of arbitration.

• Journal of information and communication convergence engineering
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• v.8 no.6
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• pp.623-629
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• 2010

A geographical routing protocol is typically utilized for a route selection of VANET. Even if it is conceptually well adapted into VANET, message delivery tends to be unreliable with frequent network partitions, which mainly come from the inherent characteristics such as high mobility and irregular traffic density. In this paper, we deal with a method to enable reliable message delivery with reflecting the traffic density on routing decision. By concatenating the message delivery cost of each of inbetween junction section, $1^{st}$ and $2^{nd}$ shortest paths are initially determined. When it is not possible to deliver the message on a junction on the 1st path, we utilize two novel ideas, that is, letting the message stay on the junction to find out a new relay node, and putting a replicated copy to reach via a detour path. By using the NS-2 network simulator, our method has been examined in terms of message delivery rate and delay. It shows that our method is much efficient than the other method in the low density environment, while it brings similar results in the high density environment.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.4
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• pp.86-94
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• 2012

VANETs can provide traffic warring service to help drivers drive safely based on the information of the traffic condition. The driver can drive safely through the warning service information provided by the VANET and know the traffic condition exactly more than through only the sight of driver. In this paper we suggest a new mechanism of updating the table to broadcast the message more rapidly based on the table driven method as the way of sending the emergency message in the VANETs. When updating the table, nodes sends only based on the message transmission success rate. In the result of simulation we could find that the suggested mechanism would reduce the delay time of the emergency message broadcast compared to the existing mechanism.