• 산업기술연구
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• 제27권B호
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• pp.235-243
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• 2007

Sensor network is used to obtain sensing data in various area. The interval to sense the events depends on the type of target application and the amounts of data generated by sensor nodes are not constant. Many applications exploit long sensing interval to enhance the life time of network but there are specific applications that requires very short interval to obtain fine-grained, high-precision sensing data. If the number of nodes in the network is increased and the interval to sense data is shortened, the amounts of generated data are greatly increased and this leads to increased amount of packets to transfer to the network. To transfer large amount of packets fast, it is necessary that the delay between successive packet transmissions should be minimized as possible. In Sensor network, since the Operating Systems are worked on the event driven, the Timer Event is used to transfer packets successively. However, since the transferring time of packet completely is varies very much, it is very hard to set appropriate interval. The longer the interval, the higher the delay and the shorter the delay, the larger the fail of transfer request. In this paper, we propose ESTEO which reduces the delay between successive packet transmissions by using SendDone Event which informs that a packet transmission has been completed.In ESTEO, the delay between successive packet transmissions is shortened very much since the transmission of next packet starts at the time when the transmission of previous packet has completed, irrespective of the transmission timee. Therefore ESTEO could provide high packet transmission rate given large amount of packets.

• Journal of Information Technology Applications and Management
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• 제23권2호
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• pp.61-80
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• 2016

The wireless mesh network (WMN) is a next-generation technology for data networking that has the advantage in cost and the flexibility in its construction because of not requiring the infra-structure such as the ethernet. This paper focuses on the optimal link scheduling problem under the wireless mesh network to effectuate real-time streaming by using the constraint programming. In particular, Under the limitation of half-duplex transmission in wireless nodes, this paper proposes a solution method to minimize the makespan in scheduling packet transmission from wireless nodes to the gateway in a WMN with no packet transmission conflicts due to the half-duplex transmission. It discusses the conflicts in packet transmission and deduces the condition of feasible schedules, which defines the model for the constraint programming. Finally it comparatively shows and discusses the results using two constraint programming solvers, Gecode and the IBM ILOG CP solver.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권9호
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• pp.2213-2231
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• 2013

Compressed sensing is a novel technology used in the field of wireless communication and sensor networks for channel estimation, signal detection, data gathering, network monitoring, and other applications. It plays a significant role in highly secure, real-time, well organized, and cost-effective data communication in smart-grid (SG) systems, which consist of multi-tier network standards that make it challenging to synchronize in power management communication. In this paper, we present a multi-layer communication model for SG systems and propose compressed-sensing based data transmission at every layer of the SG system to improve data transmission performance. Our approach is to utilize the compressed-sensing procedure at every layer in a controlled manner. Simulation results demonstrate that the proposed monitoring devices need less transmission power than conventional systems. Additionally, secure, reliable, and real-time data transmission is possible with the compressed-sensing technique.

• 반도체디스플레이기술학회지
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• 제20권3호
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• pp.108-112
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• 2021

For smart mobile devices, the wireless communication module is one of the hardware modules that consume the most energy. If we can build a multi-channel multi-interface environment using heterogeneous communication modules and operate them dynamically, data transmission performance can be highly improved by increasing the parallelism. Also, because these heterogeneous modules have different data rates, transmission ranges, and power consumption, we can save energy by exploiting a power efficient and low speed wireless interface module to transmit/receive sporadic small data. In this paper, we propose a power efficient data transmission method using heterogeneous communication networks. We also compared the performance of our proposed scheme to a conventional scheme, and proved that our proposed scheme can save energy while guaranteeing reasonable data delivery time.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.576-585
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• 2017

Dynamic thermal rating (DTR) of overhead transmission lines can provide a significant increase in transmission capacity compared to the static thermal rating. However, the DTR are usually estimated by the traditional thermal model of overhead conductor that is highly dependent on the solar, wind speed and wind direction data. Consequently, the estimated DTR would be unreliable and the safety of transmission lines would be reduced when the solar and wind sensors are out of function. To address this issue, this study proposed a novel thermal model of overhead conductor based on the thermal-electric analogy theory and Markov chain. Using this thermal model, the random variation of conductor temperature can be simulated with any specific current level and ambient temperature, even if the solar and wind sensors are out of function or uninstalled. On this basis, an estimation method was proposed to determine the DTR in the form of probability. The laboratory experiments prove that the proposed method can estimate the DTR reliably without measured solar and wind data.

• 한국멀티미디어학회논문지
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• 제18권9호
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• pp.1047-1057
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• 2015

In this paper, we propose an effective wireless transmission technology, under poor wireless transmission channel surroundings caused by speedy flying, that are able to transmit high quality video recording information and surveillance data via accessing to various wireless networking services architecture such as One-on-One, Many-on-One, One-on-Many, Over the Horizon. The Real-Time Position Analysis(RAPA) method is also suggested to provide more meaningful video information of shooting area. The suggested wireless transmission technology and RAPA can make remote control of UAV's flight route to get valuable topography information. Because of the benefit to get both of video information and GPS data of shooting area simultaneously, the result of study can be applied to various application sphere including UAV that requires high speed wireless transmission.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제8권1호
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• pp.11-17
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• 2008

Typical wireless sensor networks used in structural monitoring are continuous types wherein data transmission is progressive at all time that may include irrelevant and insignificant data and information. Continuous types of wireless monitoring systems often pose problems of handling large-sized data that may deteriorate the performance of the system. The proposed method is to suggest an event-triggered monitoring system that captures and transmits relevant data only. An error signal generated by the Principal Components Analysis (PCA) is utilized as an index for event detection and selective data transmission. With this new monitoring scheme, the remote server is relieved of unwanted data by receiving only relevant information from the wireless sensor networks. The performance of the proposed scheme was verified with simulation studies.

• International journal of advanced smart convergence
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• 제2권1호
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• pp.27-29
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• 2013

This paper discusses comparative analysis of the effects of surge protection devices (SPD) upon the power line communication channels. The quality of the data transmission channel is measured based on the data rate for the various channel parameters which include channel length and application method of the lightning protection device. The performance measurements are also carried out for various lengths of the communication channel. Experiment results show that specific combination of SPDs applied in the network causes severe degradation of the channel quality which is associated with the combination of grade levels and channel lengths.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2011년도 추계학술대회
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• pp.78-81
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• 2011

본 논문에서는 ATSC (Advanced Television Systems Committee) 지상파 DTV (digital television) 방송 시스템에서 부가 데이터 전송률을 향상시키면서 비트 오율 (bit error rate) 성능을 개선하기 위한 다중 안테나 부가데이터 전송 방식을 제안한다. 제안된 다중 안테나 전송방식은 Alamouti 기법을 사용하여 단일 안테나 전송 방식에 비해 신호대 잡음비 이득을 얻는다. 또한, 제안하는 전송 방식은 기존의 ATSC 지상파 DTV 수신기와 역호환성을 가진다는 장점이 있다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2011년도 추계학술대회
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• pp.247-250
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• 2011

본 논문에서는 ATSC (Advanced Television Systems Committee) 지상파 DTV (digital television) 방송 시스템에서 부가 데이터 전송률을 향상시키면서 비트 오율 (bit error rate) 성능을 개선하기 위한 다중 안테나 부가데이터 전송 방식을 제안한다. 제안된 다중 안테나 전송방식은 Alamouti 기법을 사용하여 단일 안테나 전송 방식에 비해 신호대 잡음비 이득을 얻는다. 또한, 제안하는 전송 방식은 기존의 ATSC 지상파 DTV 수신기와 역호환성을 가진다는 장점이 있다.