• The Magazine of the IEIE
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• v.28 no.12
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• pp.61-73
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• 2001

근거리 통신 네트워크(LAN : Local Area Network), 원거리 통신 네트워크(WAN : Wide Area Network), 대도시 지역 네트워크(MAN : Metro Area Network)는 서로 다른 표준의 전송 속도 및 프로토콜을 사용하기 때문에 네트워크 연동 등에 있어서 비용 대비 성능을 최적화 하기에 매우 어려운 상황이다. 최근에는 서로 다른 이들의 네트워크에 소요되는 대역폭의 증가에 따라 통신사업자 및 장비업체에서는 각 네트워크의 전송속도가 초당 10기가비트로 수렴될 것으로 예상하고 있다. 10기가비트 이더넷 기술은 IEEE 802.3 그룹에서 표준화가 진행중인 초고속 LAN 기술로서 기가비트에 그쳤던 LAN의 속도 개선과 아울러 MAN-WAN의 종단 네트워크 일부로써 LAN을 사용할 수 있도록 하는 차세대 기간 네트워크 기술이다. 인터넷 서비스 제공자(Internet Service Provider)들이 10기가비트 이더넷 기술을 사용되면 LAN과 MAN/WAN으로 분리되었다. 네트워크 경계가 허물어질 것으로 예상된다. 특히 급증하는 향후 트래픽의 대부분이 인터넷 트래픽임을 감안하면 이에 적합한 해결책이 절실하게 요구된다. 본 고에서는 이러한 10기가비트 이더넷 기술과 관련된 국제 표준화 동향과 기술 요소 및 10기가비트 이더넷 기술을 이용하는 경우의 응용 사례를 살펴보고자 한다.

• International journal of advanced smart convergence
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• v.8 no.2
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• pp.218-226
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• 2019

The use of Information and Communication Technologies (ICT) is the key to operate a change from the traditional manual reading of water meters and sensors to an automated system where high frequency data is remotely collected and analyzed in real time, one of the main components of a Smart Water Grid. The recent boom of ICT offers a wide range of both wired and wireless technologies to achieve this objective. We review and present in this article the most widely recognized technologies and protocols along with their respective advantages, drawbacks and applicability range which can be Home Area Network (HAN), Building Area Network (BAN) or Local/Neighborhood Area Network (LAN/NAN). We also present our findings and we give recommendations on the application of ICT in Smart Water Grids and future work needed.

• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.175-181
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• 2005

Recent measurements of local-area and wide-area traffic have shown that network traffic exhibits at a wide range of scales-Self-similarity. Self-similarity is expressed by long term dependency, this is contradictory concept with Poisson model that have relativity short term dependency. Therefore, first of all for design and dimensioning of next generation communication network, traffic model that are reflected burstness and self-similarity is required. Here self-similarity can be characterized by Hurst parameter. In this paper, when different many data traffic being integrated under various environments is arrived to communication network, Hurst Parameter's change is analyzed and compared with simulation results.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.91-94
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• 1998

ATM technology is reaching a certain level of maturity that allow for its deployment in local as well as in wide area networks. Concurrently, audiovisual applications are foreseen as one of the major users of such broadband networks. We present in this paper requriement of real-time multimedia service on B-ISDN networks and simulating the transport of MPEG-2 encoded multimedia data over ATM networks using CBR, VBR, ABR of ATM Traffic Service. We compare each delay time considering network performance and propose need for real-time multimedia service.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1319-1327
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• 2015

As wind power farm (WPF) installations continue to grow, monitoring and controlling large-scale WPFs presents new challenges. In this paper, a hierarchical network architecture is proposed in order to provide remote monitoring and control of large-scale WPFs. The network architecture consists of three levels, including the WPF comprised of wind turbines and meteorological towers, local control center (LCC) responsible for remote monitoring and control of wind turbines, and a central control center (CCC) that offers data collection and aggregation of many WPFs. Different scenarios are considered in order to evaluate the performance of the WPF communications network with its hierarchical architecture. The communications network within the WPF is regarded as the local area network (LAN) while the communication among the LCCs and the CCC happens through a wide area network (WAN). We develop a communications network model based on an OPNET modeler, and the network performance is evaluated with respect to the link bandwidth and the end-to-end delay measured for various applications. As a result, this work contributes to the design of communications networks for large-scale WPFs.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.1
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• pp.35-42
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• 2021

The position accuracy of the stand-alone Regional Navigation Satellite System (RNSS) users is more than tens of meters because of various error sources in satellite navigation signals. This paper focuses on wide-area differential (WAD) positioning technique, which is already applied in Global Navigation Satellite System (GNSS), in order to improve the position accuracy of RNSS users. According to the simulation results in the very narrow ground network in regional area, the horizontal position error of stand-alone RNSS is about RMS 11.6 m, and that of RNSS with WAD technique, named the WAD-RNSS, is about RMS 2.5 m. The accuracy performance has improved by about 78%.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.1
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• pp.43-48
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• 2021

Most existing studies on the wide-area differential global positioning system (WADGPS) used standard positioning service (SPS) receivers in their observation reference stations which provide the central control station global positioning system (GPS) measurements to generate augmentation data. In the present study, it is considered to apply a precise positioning service (PPS) receiver to an observation reference station which is located in the threatened jamming area. Therefore, the reference station network consists of a PPS receiver based observation reference station and SPS receiver based observation reference stations. In this case, to maintain correction performance P1C1 differential code bias (DCB) should be compensated. In this paper, P1C1 DCB estimation algorithm was applied to the PPS/WADGPS system and performance test results using measurements in the Korean Peninsula were presented.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.341-360
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• 2012

The network topology for a wide area sensor network has to support connectivity and a prolonged lifetime for the many applications used within it. The concepts of structure and group in sociology are similar to the concept of cluster in wireless sensor networks. The clustering method is one of the preferred ways to produce a topology for reduced electrical energy consumption. We herein propose a cluster topology method based on sociological structures and concepts. The proposed sociological clustering topology (SOCT) is a method that forms a network in two phases. The first phase, which from a sociological perspective is similar to forming a state within a nation, involves using nodes with large transmission capacity to set up the global area for the cluster. The second phase, which is similar to forming a city inside the state, involves using nodes with small transmission capacity to create regional clusters inside the global cluster to provide connectivity within the network. The experimental results show that the proposed method outperforms other methods in terms of energy efficiency and network lifetime.

• Journal of KIISE:Information Networking
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• v.37 no.1
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• pp.27-34
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• 2010

In this paper, we examine a long-range dependence in an active measurement of a network traffic which has been a well known characteristic from analyses of a passive network traffic measurement. To this end, we utilize RTT(Round Trip Time), which is a typical active measurement measured by PingER project, and perform a relevant analysis to a time series of both RTT and its volatilities. The RTT time series exhibits a long-range dependence or a 1/f noise. The volatilities, defined as a higher-order variation, follow a log-normal distribution. Furthermore, volatilities show a long-range dependence in relatively short time intervals, and a long-range dependence and/or 1/f noise in long time intervals. From this study, we find that the long-range dependence is a characteristic of not only a passive traffic measurement but also an active measurement of network traffic such as RTT. From these findings, we can infer that the long-range dependence is a characteristic of network traffic independent of a type of measurements. In particular, an active measurement exhibits a 1/f noise which cannot be usually found in a passive measurement.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.5
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• pp.980-997
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• 2013

Nowadays, wireless communication has a great advantage in technology. We use wireless devices almost in all expected life such as: entertainment, working and recently in the healthcare area, where Wireless Body Area Networks (WBANs) become a hot topic for researchers and system designers. Recent work on WBANs focus on related issues to communication protocol, especially ZigBee network is fine tuned to meet particular requirements in healthcare area. For example, some papers present real-time patient monitoring via ZigBee communication given the short distance between body sensors and remote devices, while the other work solve the limited coverage problem of Zigbee by designing mechanisms to relay Zigbee data to other types of wire or wireless infrastructure. However, very few of them investigate the scenarios of ZigBee coexisting or integrated with other networks. In this paper, we present the real-time data transmission from ZigBee end devices to Wide Area Network (WAN), Worldwide interoperation for microwave access network (WiMAX) and Long Term Evolution network (LTE). We provide in detail the ZigBee gateway components. Our simulation is conducted by OPNET, we visualize many topology network scenarios in ZigBee hybrid system. The results in simulation show that ZigBee end devices can successfully transmit data in real-time to other network end devices.