• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.770-773
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• 2004

The transmission loss coefficient is very important acoustic property in parallel with absorption and acoustic impedance categorizing the acoustical materials, which can control the acoustical problems. At the same time, the transmission loss coefficient is a key parameter to choose the optimum material for the analysis of acoustical characteristics of material using SEA(Statistical Energy Analysis). In this paper, the acoustic transmission loss measurement system using 4-microphone TL tube is applied to the exhaust system, which is one of the most important acoustic control parameters in a car, based on the idea calculating the full transfer matrix. The theoretical background and measurement system are introduced, and finally the measurement results are verified.

• Journal of Ubiquitous Convergence Technology
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• 제1권1호
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• pp.35-41
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• 2007

In mobile ad-hoc wireless networks, one of the most important challenging issues is how to conserve energy, maximizing the lifetime of route(networks) in the view points of both power and mobility of nodes. However, many transmission methods presented in the previous works can not satisfy these two objectives simultaneously. To obtain these two goals, in this paper we propose an architecture to support power saving transmission services with route stability in mobile ad-hoc wireless networks. The proposed architecture consists of two parts, the underlying route stability method to support route(network) lifetime and the power saving transmission methods. The performance evaluation of the proposed architecture is achieved via simulation and analysis.

• Wind and Structures
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• 제10권3호
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• pp.249-268
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• 2007

Past experience indicates that the majority of failures of electrical transmission tower structures occurred during high intensity wind events, such as downbursts. The wind load distribution associated with these localized events is different than the boundary layer wind profile that is typically used in the design of structures. To the best of the authors' knowledge, this study represents the first comprehensive investigation that assesses the effect of varying the downburst parameters on the structural performance of a transmission line structure. The study focuses on a guyed tower structure and is conducted numerically using, as a case study, one of the towers that failed in Manitoba, Canada, during a downburst event in 1996. The study provides an insight about the spatial and time variation of the downburst wind field. It also assesses the variation of the tower members' internal forces with the downburst parameters. Finally, the structural behaviour of the tower under critical downburst configurations is described and is compared to that resulting from the boundary layer normal wind load conditions.

• 에너지공학
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• 제22권2호
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• pp.83-89
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• 2013

에너지사용은 우리생활과 밀접한 관계성을 유지하고 있다. 사계절이 뚜렷한 우리나라로서는 건물분야에 냉,난방이 필수품처럼 여겨지는 세대에 살고있어 에너지 사용과 유지에 새로운 트렌드를 요구하고 있다. 이에따라 정부는 신축 및 기존건축물의 에너지효율 개선을 위해서 단열기준을 지속적으로 강화하여 에너지절감을 꾀하고 있다. 공동주택의 에너지효율 분석중 가장 중요한 요소가 열관류율이며 그값은 외피면적비에 대한 창면적비에 따라 난방에너지 요구량이 큰차이를 보여주고 있다. 그러므로 지속적인 효율개선 정책과 외피면적에 대한 창면적비의 규제가 필요한 시점이라 생각한다.

• ETRI Journal
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• 제34권6호
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• pp.807-815
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• 2012

In this paper, we propose a scheme for partially dynamic lane control for energy saving in multilane-based high-speed Ethernet. In this scheme, among the given transmission lanes, at least one lane is always operating, and the remaining lanes are dynamically activated to alleviate the network performance in terms of queuing delay and packet loss in the range of acceptance. The number of active lanes is determined by the decision algorithm based on the information regarding traffic and queue status. The reconciliation sublayer adjusts the transmission lane with the updated number of lanes received from the algorithm, which guarantees no processing delay in the media access control layer, no overhead, and minimal delay of the exchanging control frames. The proposed scheme is simulated in terms of queuing delay, packet loss rate, lane changes, and energy saving using an OPNET simulator. Our results indicate that energy savings of around 55% (or, when the offered load is less than 0.25, a significant additional savings of up to 75%) can be obtained with a queuing delay of less than 1 ms, a packet loss of less than $10^{-4}$, and a control packet exchange time of less than $0.5{\mu}s$ in random traffic.

• International Journal of Contents
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• 제7권1호
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• pp.8-13
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• 2011

For energy-efficiency in Wireless Sensor Networks (WSNs), when a sensor node detects events, the sensing period for collecting the detailed information is likely to be short. The lifetime of WSNs decreases because communication modules are used excessively on a specific sensor node. To solve this problem, the TARP decentralized network packets to neighbor nodes. It considered the average data transmission rate as well as the data distribution. However, since the existing scheme did not consider the energy consumption of a node in WSNs, its network lifetime is reduced. In this paper, we propose an energy awareness congestion control scheme based on genetic algorithms in WSNs. The proposed scheme considers the remaining amount of energy and the transmission rate on a single node in fitness evaluation. Since the proposed scheme performs an efficient congestion control, it extends the network lifetime. In order to show the superiority of the proposed scheme, we compare it with the existing scheme through performance evaluation. It is shown that the proposed scheme enhances the data fairness and improves the network lifetime by about 27% on average over the existing scheme.

• Journal of Communications and Networks
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• 제12권4호
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• pp.358-365
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• 2010

We develop a low complexity cooperative diversity protocol for low energy adaptive clustering hierarchy (LEACH) based wireless sensor networks. A cross layer approach is used to obtain spatial diversity in the physical layer. In this paper, a simple modification in clustering algorithm of the LEACH protocol is proposed to exploit virtual multiple-input multiple-output (MIMO) based user cooperation. In lieu of selecting a single cluster-head at network layer, we proposed M cluster-heads in each cluster to obtain a diversity order of M in long distance communication. Due to the broadcast nature of wireless transmission, cluster-heads are able to receive data from sensor nodes at the same time. This fact ensures the synchronization required to implement a virtual MIMO based space time block code (STBC) in cluster-head to sink node transmission. An analytical method to evaluate the energy consumption based on BER curve is presented. Analysis and simulation results show that proposed cooperative LEACH protocol can save a huge amount of energy over LEACH protocol with same data rate, bit error rate, delay and bandwidth requirements. Moreover, this proposal can achieve higher order diversity with improved spectral efficiency compared to other virtual MIMO based protocols.

• Journal of information and communication convergence engineering
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• 제7권2호
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• pp.223-230
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• 2009

For pulse trigger way and the energy injection rate according to PET ($Pause^{10-90}$ $Energy^{20-40}$ $Trigger^{1-7}$) function, indeed, human body condition, period of dormancy in this research about this back correctly adjustment possible and designed harmless micro carrying along style hair exclusion so that can design and manufacture and run special quality examination and Xenon flash lamp to crawl in human body. Because creating individual's skin model to do stable treatment by light transmission way by skin impedance and measure, must embody treatment special quality of most suitable that draw skin color, energy, wave length, approximately, transmission time, pulse delay etc. and want. Specially, saved standard of war treatment pulse modeling by skin impedance, and manufacture pulse modeling system of most suitable by skin subordinate, and embody suitable treatment pulse. Specially, embody as could do root of a hair exclusion being emitted in pulse form using multi wave length of 560nm, 590nm, 640nm, 755nm and embodied clinical data. If become research repletion furthermore little more, is seen that can approximate in commercialization.

• 한국통신학회논문지
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• 제37B권12호
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• pp.1186-1194
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• 2012

무선 센서 네트워크에서 에너지 효율성을 문제를 해결하기 위해 다중 홉 전송 방식을 사용할 수 있다. 다중 홉전송 방식은 전체 에너지 소비량을 줄일 수는 있으나 네트워크의 라이프타임을 심각하게 감소시킬 수 있다. 노드들은 자신의 잔여에너지에 따라 다른 노드의 패킷을 릴레이 해줄지를 결정해야 한다. 이러한 문제를 해결하기 위해 우리는 strike and bargaining 알고리즘 (SBA)를 제안한다. 라우팅 경로는 각 노드의 특정값 (wage)에 따라 결정된다. 각 노드는 주변 노드와 wage를 협상한 후 합당한 wage를 결정하고 그에 따라 최적의 라우팅 경로를 결정한다. 분석과 시뮬레이션을 통해 우리는 SBA가 최적의 성능에 근접할 수 있음을 보인다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권4호
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• pp.894-903
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• 2014

Insertion loss prediction of large acoustical enclosures using Statistical Energy Analysis (SEA) method is presented. The SEA model consists of three elements: sound field inside the enclosure, vibration energy of the enclosure panel, and sound field outside the enclosure. It is assumed that the space surrounding the enclosure is sufficiently large so that there is no energy flow from the outside to the wall panel or to air cavity inside the enclosure. The comparison of the predicted insertion loss to the measured data for typical large acoustical enclosures shows good agreements. It is found that if the critical frequency of the wall panel falls above the frequency region of interest, insertion loss is dominated by the sound transmission loss of the wall panel and averaged sound absorption coefficient inside the enclosure. However, if the critical frequency of the wall panel falls into the frequency region of interest, acoustic power from the sound radiation by the wall panel must be added to the acoustic power from transmission through the panel.