• 한국통신학회논문지
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• 제37권4B호
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• pp.258-268
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• 2012

무선 센서 네트워크(WSN)에서는 저가 및 저 전력 센서로 구성되기 때문에 센서의 임무를 성공적으로 수행하면서 적은 에너지를 소모하는 것이 중요한 문제로 부각된다. 기존의 클러스터링 WSN에서는 헤드의 결정 및 헤드에 의한 데이터 수집과 전송 방안이 전체 네트워크의 성능에 큰 영향을 준다. 본 논문은 클러스터링 WSN에서 데이터 전송의 방향성을 고려한 하이브리드(Hybrid) 클러스터링 방법을 제안한다. 데이터의 효율적인 전송을 위해 모든 센서노드가 싱크로 데이터를 전송할 때 클러스터헤드를 거쳐 전송할 것인지 클러스터 헤드를 거치지 않고 싱크로 직접 전송할 것인지를 싱크, 헤드위치, 해당 센서노드의 위치에 따라 이원화 하는 하이브리드 라우팅 기법이다. 실험을 통하여 LEACH(Low Energy Adaptive Clustering Hierarchy) 방식과 비교하여 데이터를 싱크에서 역방향으로 전송 하지 않음으로써 거리와 에너지소모를 줄일 수 있음을 확인하였다.

• 디지털산업정보학회논문지
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• 제11권3호
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• pp.79-90
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• 2015

Multipath routing technique is recognized as one of the effective approaches to improve the reliability of data forwarding. However, the traditional multipath routing focuses only on how many paths are needed to ensure a desired reliability. For this purpose, the protocols construct additional paths and thus cause significant energy consumption. These problems have motivated the study for the energy-efficient and reliable data forwarding. Thus, this paper proposes an energy-efficient concurrent multipath routing protocol with a small number of paths based on interaction between paths. The interaction between paths helps to reinforce the multipath reliability by making efficient use of resources. The protocol selects several nodes located in the radio overlapped area between a pair of paths as bridge nodes for the path-interaction. In order to operate the bridge node efficiently, when the transmission failure has detected by overhearing at each path, it performs recovery transmission to recover the path failure. Simulation results show that proposed protocol is superior to the existing multipath protocols in terms of energy consumption and delivery reliability.

• Coupled systems mechanics
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• 제6권2호
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• pp.157-174
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• 2017

In the present investigation reflection and transmission of plane waves at an elastic half space and piezothermoelastic solid half space with fractional order derivative is discussed. The piezothermoelastic solid half space is assumed to have 6 mm type symmetry and assumed to be loaded with an elastic half space. It is found that the amplitude ratios of various reflected and refracted waves are functions of angle of incidence, frequency of incident wave and are influenced by the piezothermoelastic properties of media. The expressions of amplitude ratios and energy ratios are obtained in closed form. The energy ratios are computed numerically using amplitude ratios for a particular model of graphite and Cadmium Selenide (CdSe). The variations of energy ratios with angle of incidence are shown graphically. The conservation of energy across the interface is verified. Some cases of interest are also deduced from the present investigation.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2005년도 춘계학술대회 논문집
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• pp.5-9
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• 2005

One of the imminent problems to be solved within wireless sensor network is to balance out energy dissipation among deployed sensor nodes. In this paper, we present a transmission relay method of communications between BS (Base Station) and CHs (Cluster Heads) for balancing the energy consumption and extending the average lifetime of sensor nodes by the fuzzy logic application. The proposed method is designed based on LEACH protocol. The area deployed by sensor nodes is divided into two groups based on distance from BS to the nodes. RCH (Relay Cluster Head) relays transmissions from CH to BS if the CH is in the area far away from BS in order to reduce the energy consumption. RCH decides whether to relay the transmissions based on the threshold distance value that is obtained as a output of fuzzy logic system. Our simulation result shows that the application of fuzzy logic Provides the better balancing of energy depletion and Prolonged lifetime of the nodes.

• Earthquakes and Structures
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• 제18권6호
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• pp.743-752
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• 2020

The phenomenon of reflection and transmission of plane waves at an interface between fluid half space and orthotropic piezothermoelastic solid half-space with two-temperature has been investigated. Energy ratios of various reflected and transmitted waves are computed with the use of amplitude ratios. The law of conservation of energy across the interface has been justified. It is found that the energy ratios are the functions of angle of incidence, frequency of independent wave and depend on the different piezothermoelastic material. A piezothermoelastic material has been considered which is in welded contact with water. Variations of energy ratios corresponding to the reflected waves and transmitted waves are computed and shown graphically for the two different models. A particular reduced case of interest is also discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권4호
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• pp.1419-1436
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• 2020

For an energy harvesting sensor network, when the network lifetime is not the only primary goal, maximizing the network performance under environmental energy harvesting becomes a more critical issue. However, clustering protocols that aim at providing maximum information throughput have not been thoroughly explored in Energy Harvesting Wireless Sensor Networks (EH-WSNs). In this paper, clustering protocols are studied for maximizing the data transmission in the whole network. Based on a long short-term memory (LSTM) energy predictor and node energy consumption and supplement models, an uneven clustering protocol is proposed where the cluster head selection and cluster size control are thoroughly designed for this purpose. Simulations and results verify that the proposed scheme can outperform some classic schemes by having more data packets received by the cluster heads (CHs) and the base station (BS) under these energy constraints. The outcomes of this paper also provide some insights for choosing clustering routing protocols in EH-WSNs, by exploiting the factors such as uneven clustering size, number of clusters, multiple CHs, multihop routing strategy, and energy supplementing period.

• Journal of Korean Vacuum Science & Technology
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• 제2권1호
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• pp.1-8
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• 1998

The uniform distributed pumping model is used to derive analytic expressions of the pressure profile for the molecular flow regime in linearly tapered or flared(conical or pyramidal) tubes with wall sorption. The concept of transmission conductance for sticky tubes of arbitrary shape is newly introduced to calculate the transmission probability using the pressure profile. The transmission probability obtained analytically for a conical sticky tube is compared with that from the Monte Carlo simulation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.391-395
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• 1997

The transmission of sound and vibration through structures is of interest in many noise control problems, including architectural acoustics, sound transmission through air craft, spacecraft and ship, and the transmission of noise through machinery and engine enclosures. Statistical Energy Analysis provides a simple and accurate method of approaching these problems. In this paper, comparing the measured coupling loss factor of plate-beam with measured coupling loss factor of mass on the junction will be inspected.

• Wind and Structures
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• 제8권2호
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• pp.89-106
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• 2005

For estimating the vortex excited vibrations of overhead transmission lines, the Energy Balance Principle (EBP) is well established for spans damped near the ends. Although it involves radical simplifications, the method is known to give useful estimates of the maximum vibration levels. For very long spans, there often is the need for a large number of in-span fittings, such as in-span Stockbridge dampers, aircraft warning spheres etc. This adds complexity to the problem and makes the energy balance principle in its original form unsuitable. In this paper, a modified version of EBP is described taking into account in-span damping and in particular also aircraft warning spheres. In the first step the complex transcendental eigenvalue problem is solved for the conductor with in-span fittings. With the thus determined complex eigenvalues and eigenfunctions a modified energy balance principle is then used for scaling the amplitudes of vibrations at each resonance frequency. Bending strains are then estimated at the critical points of the conductor. The approach has been used by the authors for studying the influence of in-span Stockbridge dampers and aircraft warning spheres; and for optimizing their positions in the span. The modeling of the aircraft warning sphere is also described in some detail.

• 한국의학물리학회지:의학물리
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• 제16권3호
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• pp.155-159
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• 2005

생체에 이식되는 장치에 사용하기 위한 무선에너지 전송 시스템을 개발하였다. 이것은 체내에 이식된 장치에 경피적으로 전기에너지를 공급할 수 있는 것이다 경피적으로 결합된 트랜스포머의 권선간의 거리는 인간의 피부 두께를 고려하여 약 10$\~$20 mm이다. 본 연구에서는 Class-E 공진증폭기를 사용하여 높은 효율을 얻고자 하였다. 최대 전류는 각 주파수에서 50 mA 이상의 전류를 얻을 수 있었다. 개발된 시스템은 500 kHz, 1 MHz 및 4 MHz의 서로 다른 주파수에서 정확하게 동작하고 있다는 것을 보여주고 있다.