• Journal of the Korea Society for Simulation
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• v.16 no.2
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• pp.55-64
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• 2007

The sensor nodes on the sensor network transmit the reply for the queries of ADV(Advertisement) message from sink node, and the sink node presents the received information to users. To find the relevant sensor nodes, routing algorithms disseminates ADV messages to the whole network. Thus not only the relevant sensor nodes but also the irrelevant ones consume considerable amount of energy. To alleviate such kind of energy consumption, this thesis proposes a new routing algorithm and coins it Directed Messaging. It propagates ADV message only to the limited direction and changes the direction until the requested sensor node is found. In this way, Directed Messaging reduces unnecessary energy consumption and enhance the efficiency of the networks. Performance of the Directed Messaging algorithm is evaluated through simulation and compared with Directed Diffusion algorithm. Simulation results show that it has better performance than Directed Diffusion.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.944-956
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• 2013

Drivers need lots of information when they drive on the highway, however it is necessary and important to be provided information which is appropriate formation. In order to offer the suitable information, adequate size, quantity, and frequency of provided information are required for the drivers. To evaluate propriety of the expressed message of VMS that provides real-time traffic conditions, first of all, the amount of message about legibility distance and viewing should be estimated. In this research, drivers' characteristics of VMS message design were also reviewed to enhance the efficiency of VMS. And legibility distance, the amount of viewing information, and ratio of viewing information were analyzed on the currently operating VMS. The results of this study proposed that the appropriate size, quantity, and frequency were concluded by the legibility and memory of message on the real driving conditions. Consequently, these design methods of VMS could be expected to improve the transmitting capability of highway information to drivers.

• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.277-285
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• 2002

This paper proposes and analyzes an error control scheme for the transmission control based real-time communication, such as FDDI, TDMA, and wireless LAN, which delivers the message according to the round robin fashion after the off-line bandwidth allocation. Taking into account the time constraint of each message, the proposed error control scheme makes the receiver transmit the error report via asynchronous traffic while the sender resend the requested message via overallocated access time which is inevitably introduced by the bandwidth allocation procedure for hard real -time guarantee. The error control procedure does not interfere other real -time message transmissions. In addition, as each frame contains the size of the message it belongs, the receiver can recognize the end of completion of message transmission. This enables earlier error report to the receiver so that the sender can cope with more network errors. The analysis results along with simulation performed via SMPL show that the proposed scheme is able to enhance the deadline meet ratio of messages by overcoming the network errors. Using the proposed error control scheme, the hard real -time network can be built at cost lower than, but performance comparable to the expensive dual link network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10B
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• pp.1043-1049
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• 2009

Broadcast of sink node is used for network management, data collection by query and synchronization in wireless sensor networks. Simple flooding scheme induces the broadcast storm problem. The MPR based broadcast schemes reduce redundant retransmission of broadcast packets. MPR is a set of one hop neighbor nodes which have to relay broadcast message to cover all two hop neighbors. Though MPR can reduce redundant retransmission remarkably, it still suffers from energy waste problem caused by collision and duplicate packets reception. This paper proposes a new MPR based sink broadcast scheme using 3-channel. The proposed scheme reduces energy consumption by avoiding duplicate packet reception, while increases reliability by reducing collision probability remarkably. The results of analysis and simulation show that the proposed scheme is more efficient in energy consumption compared to the MPR based scheme. The result also shows that the proposed scheme reduces delivery latency by evading a contention with other relay nodes and improves reliability of broadcast message delivery by reducing collision probability.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.43-50
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• 2010

Recently, the Internet telephony has been used rather than the traditional telephony by many Internet users, with low cost. Session Initiation Protocol(SIP) is the standard of application layer protocol for establishment and disconnection of the session for Internet telephony. SIP mainly runs over the UDP for transport. So in case of the loss of the INVITE request message, the message is retransmitted by an appropriate timer for reliable transmission of the UDP message. Though the retransmission is useful for ensuring the reliability of SIP messages sent by the users, it may cause the overload traffic in the SIP proxy server. The overload in SIP proxy servers results in the loss of many input messages. This paper presents a non-linear overload control algorithm to resolve the overload condition of the server. we simulate our proposed algorithm using the network simulator ns-2. The simulation results show that the throughput of the server with the proposed algorithm have been improved about 12% compared to the existing linear control algorithm.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.8
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• pp.825-834
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• 2018

Broadcasting is a basic data communication method for interconnection networks. There are two types of broadcasting. One-to-all broadcasting is to transmit a message from one node to all other nodes and all-to-all broadcasting is to transmit a message from all the nodes that have messages to other nodes. And by the using way of the transmission port per unit time, there are two schemes of broadcasting. Single port telecommunication(SLA) is to transmit messages from one node that contains the messages to one adjacent node only and all port telecommunication(MLA) is to transmit messages from one node to all adjacent nodes within a time of unit. Matrix hypercube is that an interconnection network has improved network cost than that of hypercube with the same number of nodes. In this paper, we analyze broadcasting scheme of matirx hypercube. First, we propose one-to-all and all-to-all broadcasting algorithms of matrix hypercube. And we prove that one-to-all broadcasting times are 2n+1 and $2{\lceil}{\frac{n}{2}}{\rceil}+1$ based on the SLA and MLA models, respectively. Also, we show all-to-all broadcasting time using SLA model is $5{\times}2^{\frac{n}{2}}-2$ when n=even, and is $5{\times}2^{\frac{n-1}{2}}+2$ when n=odd.

• Asia Marketing Journal
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• v.11 no.4
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• pp.49-67
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• 2010

Previous researches have proven that corporate social responsibility(adhere CSR) is positively related to corporate performance. But Most of CSR related researches have several limitations. One of limitations is that those researches treated CSR as unidimensional construct. Almost researchers in the area of CSR concepts insisted that CSR is consist of multi dimensions. Carroll's four dimensions of CSR have been utilized by numerous academicians. Carroll asserted that CSR is composed of four dimensions: economic, legal, ethical, and philanthropic responsibility. But Carroll's dimensions were revised as three dimensions by Schwartz and Carroll, because ethical and philanthropic responsibility are not mutually exclusive. If CSR construct is composed of multiple dimensions, a message related to one of dimensions changes beliefs or evaluations about other dimensions that are not mentioned in the message. This phenomenon is called as "spillover effect". According to Ahluwalia, Unnava, and Burnkrant, negative information spills over to attributes that are associated with the target attributes but not mentioned in the message. Like this, this preponderant effect of negative information over positive information has been termed the "negativity effect". In this paper, authors try to prove the spillover effect and negativity effect among Schwartz and Carroll's three dimensions(economic, legal, and ethical responsibility) of CSR. The results of this study show that messages related to legal and ethical responsibility cause spillover effect and influence consumers' evaluation to other dimensions. Moreover, when negativity effect is added on spillover effect, spillover effect is more increased. It means that negative messages related to legal and ethical responsibility is more harmful to corporate image than negative message related to economic responsibility. The results of this study will help companies to manage corporate image using CSR messages as marketing communication tools. Companies should manage messages related to legal and ethical responsibility for more efficiently managing corporate image. Specially, because negative messages related to legal and ethical responsibility are more harmful to corporate image, companies must take care not to spread out negative message related to legal and ethical responsibility. Finally, we discuss the implications of the findings and limitations.

• ICROS
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• v.4 no.1
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• pp.28-32
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• 1998

본 글에서는 실시간 분산처리 제어기를 위한 시뮬레이터의 구조를 제시한다. 분산처리 환경에서 각각의 노드 간에 비주기적으로 발생하는 메시지와 주기적으로 발생하는 데이터의 교환을 위한 통신 구조와 가상머신을 이용한 객체지향형 시뮬레이터 구조를 제시하고자 한다. 그리고 제안된 구조의 소프트웨어를 이용하여 PID 제어기를 설계하는 예제를 보여준다.

• 대학교육
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• s.86
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• pp.74-86
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• 1997

인도의 간디는 이 세상에는 일곱 가지의 사회악이 있다고 말했다. 원칙이 없는 정치, 노동이 없는 생산, 도덕이 없는 상업, 양심이 없는 쾌락, 특성이 없는 교육, 인간성이 없는 과학, 희생이 없는 종교 예배가 그 내용이다. 마치 지금 우리 사회를 적확하게 진단하고 우리에게 던져준 메시지처럼 보인다. 이제 우리는 우리가 부딪친 몇 가지 주요 현안을 살펴보고, 21세기를 앞두고 이 땅에서 지식인이 나갈 행보를 곰곰히 생각할 시점에 왔다.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.5
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• pp.464-474
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• 2000

All-to-all personalized communication, or complete exchange, is at the heart of numerous applications, such as matrix transposition, fast Fourier Transform(FFT), and distributed table lookup.We present an efficient all-to-all personalized communication algorithm for a 2D torus inwormhole-routed networks. Our complete exchange algorithm adopts divide-and-conquer approach toreduce the number of start-up latency significantly, which is a good metric for network performancein wormhole networks. First, we divide the whole network into 2x2 basic cells, After speciallydesignated nodes called master nodes have collected messages to transmit to the rest of the basic cell,only master nodes perform complete exchange with reduced network size, N/2 x N/2. When finishedwith this complete exchange in master nodes, these nodes distribute messages to the rest of the masternode, which results in the desired complete exchange communication. After we present our algorithms,we analyze time complexities and compare our algorithms with several previous algorithms. And weshow that our algorithm is efficient by a factor of 2 in the required start-up time which means thatour algorithm is suitable for wormhole-routed networks.