• 제어로봇시스템학회논문지
• /
• 제9권12호
• /
• pp.1055-1064
• /
• 2003

In many automated systems, such as manufacturing systems and process plants, a fieldbus is a very important component for the exchange of various and sometimes crucial information. Some of the information has a tendency to rapidly lose its value as time elapses after its creation. Such information or data is called real-time data that includes sensor values and control commands. In order to deliver these data in time, the fieldbus network should be tailored to have short delay with respect to the individual time limit of various data. Fine-tuning the network for a given traffic requires the knowledge on the relationship between the protocol parameters such as timer values and the performance measure such as network delay. This paper presents a mathematical performance model to calculate communication delays of the Profibus-FMS network when the timer value and the traffic characteristics are given.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권5호
• /
• pp.2362-2378
• /
• 2017

To mitigate the performance degradation caused by performance anomaly, a number of channel assignment algorithms have been proposed for multi-rate wireless mesh networks. However, network conditions have not been fully considered for routing process in these algorithms. In this paper, a joint scheme called Multi-rate Dijkstra's Shortest path - Rate Separated (MDSRS) is proposed, combining routing metrics and channel assignment algorithm. In MDSRS, the routing metric are determined through the synthesized deliberations of link costs and rate matches; then the rate separated channel assignment is operated based on the determined routing metric. In this way, the competitions between high and low rate links are avoided, and performance anomaly problem is settled, and the network capacity is efficiently improved. Theoretical analysis and NS-3 simulation results indicate that, the proposed MDSRS can significantly improve the network throughput, and decrease the average end-to-end delay as well as packet loss probability. Performance improvements could be achieved even in the heavy load network conditions.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
• /
• pp.269-273
• /
• 2004

This paper presents a comparative performance analysis of a network accelerator model based on M/M/l queuing system. It assumes the Poisson distribution as its input traffic load. The decoding delay is employed as a performance analysis measure. Simulation results based on the proposed model show only $15\%$ differences with respect to actual measurements on field traffic for BCM5820 accelerator device. The performance analysis model provides with reasonable hardware structure of network servers, and can be used to span design spaces statistically.

• 제어로봇시스템학회논문지
• /
• 제11권8호
• /
• pp.709-716
• /
• 2005

As a way to build more efficient and intelligent container cranes for todays hub ports, communication networks are used to interconnect numerous sensors, actuators, controllers, and operator switches and consoles that are spatially distributed over a crane. Various signals such as sensor values and operator's commands are digitized and broadcast on the network instead of using separate wiring cables. This not only makes the design and manufacturing of a crane more efficient, but also easier implementation of intelligent control algorithms. This paper presents the performance evaluation of CAN(Controller Area Network), TTP(Time Triggered Protocol) and Byteflight that can be used for cranes. Through discrete event simulation, several important quantitative performance factors such as the probability of a transmission failure, average system delay (data latency) and maximum system delay have been evaluated.

• Journal of Communications and Networks
• /
• 제17권2호
• /
• pp.118-125
• /
• 2015

In this paper, we propose a method to reduce mobile social network services (SNSs) traffic using a mobile integrated SNS gateway (MISG) to improve network communication performance between the mobile client and SNS servers. The gateway connects the client and SNS servers using the contents adapter and the web service adapter and helps to improve communication performance using its cache engine. An integrated SNS application, the user's client, communicates with the gateway server using integrated SNS protocol. In addition, the gateway can alert the client to new SNS contents because of the broker server implemented by the message queuing telemetry transport protocol. We design and develop the modules of the gateway server and the integrated SNS application. We then measure the performance of MISG in terms of content response time and describe the result of the experiment.

• Journal of Communications and Networks
• /
• 제10권4호
• /
• pp.384-395
• /
• 2008

Random network coding can be viewed as a single block code applied to all source packets. To manage the concomitant high coding complexity, source packets can be partitioned into generations; block coding is then performed on each set. To reach a better performance-complexity tradeoff, we propose a novel concatenated network code which mixes generations while retaining the desirable properties of generation-based coding. Focusing on the code's erasure performance, we show that the probability of successfully decoding a generation on erasure channels can increase substantially for any erasure rate. Using both analysis (for small networks) and simulations (for larger networks), we show how the code's parameters can be tuned to extract best performance. As a result, the probability of failing to decode a generation is reduced by nearly one order of magnitude.

• 대한임베디드공학회논문지
• /
• 제6권4호
• /
• pp.231-241
• /
• 2011

Recently, system virtualization has been applied to consumer electronics (CE) such as smart mobile phones. Although multi-core processors have become a viable solution for complex applications of consumer electronics, the issue of utilizing multi-core resources in the virtualization layer has not been researched sufficiently. In this paper, we present a new hypervisor design and implementation for multi-core CE devices. We concretely describe virtualization methods for a multi-core processor and multi-core-related subsystems. We also analyze bottlenecks of network performance in a virtualization environment that supports multimedia applications and propose an efficient virtual interrupt distributor. Our new multi-core hypervisor improves network performance by 5.5 times as compared to a hypervisor without the virtual interrupt distributor.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2019년도 춘계학술대회
• /
• pp.456-458
• /
• 2019

본 연구에서는 LTE-R을 기반으로 하는 철도통신에서 응용서비스로서 스트리밍 오디오의 전송성능을 분석하고자 한다. 본 연구에서 성능분석은 NS(Network Simulator)-3에 기반한 컴퓨터 시뮬레이션을 사용하여 수행하며, 분석대상 응용서비스로는 MPEG(Moving Picture Experts Group)-4의 오디오 프레임을 사용한다. 본 연구의 결과는 LTE-R 네트워크 구축뿐 아니라 LTE-R 네트워크를 대상으로 하는 응용서비스 개발의 기초자료로 활용이 가능하다.

• 산업경영시스템학회지
• /
• 제45권3호
• /
• pp.214-227
• /
• 2022

The successful implementation of green supply chain management(GSCM) practices requires a level of cooperation that can be difficult to conduct. Despite this challenge, limited scholarly attention has been paid to exploring how the implementation of GSCM practices can be effectively facilitated and enhanced through accumulated social capital with suppliers. Based on social capital theory, this study postulates that supplier network characteristics derived from social capital with key suppliers can be critical antecedents of GSCM, which in turn enhances the firm's environmental performance. To test hypotheses, data were collected from 330 firms in 15 countries, and structural equation modeling was employed. Results show that GSCM improves environmental performance, and structural and cognitive social capitals of the supplier network act as antecedents and lead to GSCM implementation.

• 경영과정보연구
• /
• 제35권2호
• /
• pp.45-66
• /
• 2016

기업들은 기술협력 네트워크를 통하여 새로운 고급기술과 지식을 내부화시키고 활용함으로써 규모 및 범위의 경제를 실현할 수 있고, 기술협력 네트워크의 파트너 기업과 위험과 비용을 분담할 수 있으며, 제품의 시장우위를 선점하거나 시장에서의 자사의 위치를 강화할 수 있다. 이러한 기술협력 네트워크의 이점에 근거하여 현재까지 기존의 관련연구들은 일반적으로 기술협력이 기업의 경영성과에 긍정적인 영향을 미치는가에 집중되어왔다. 그러나 기존의 기술협력과 경영성과의 관계를 규명한 연구들은 단지 경영성과에 관한 기술협력 네트워크의 역할을 조명하는데 그친다. 본 연구에서는 기존의 연구들에서 간과된 기술협력 네트워크의 중간과정을 보호 메커니즘, 관계학습, 관계성과로 분류하고, 이를 자원기반이론의 일반적 구조인 자원, 역량, 성과에 각각 적용하였다. 실증분석의 결과는 다음과 같다. 관계특유투자와 관계자본은 역량으로서의 관계학습에 긍정적인 영향을 미치고 있는 것으로 나타났다. 둘째, 정보교환, 공동의 정보이해, 관계특유 기억개발은 관계지향성에 긍정적인 영향을 나타내고 있으나, 정보교환이 효율성과 효과성에 미치는 유의성은 발견되지 않았다. 셋째, 관계특유투자는 관계자본에 긍정적인 영향을 미치고 있으며, 효율성과 효과성은 장기지향성에 긍정적인 영향을 미치고 있는 것으로 나타났다. 본 연구는 비대칭적인 기술의존 구조를 형성하는 기술협력 네트워크 관계에서 자원기반이론에 입각하여 기존의 연구들이 간과하고 있는 보호 메커니즘, 관계학습, 관계성과의 역할을 규명함으로써 보호 메커니즘과 관계학습의 중요성을 제시하였다. 또한 협력 파트너와의 관계에서 기업의 어떠한 행동변화를 유발함으로써 관계성과에 도달하는가를 살펴봄으로써 보호 메커니즘은 기술협력 파트너와의 관계학습을 통해 관계성과에 영향을 제공할 수 있다는 점을 분석하는데 의의가 있다고 볼 수 있겠다.