• International Journal of Internet, Broadcasting and Communication
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• 제13권3호
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• pp.25-33
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• 2021

Energy-harvesting wireless sensor networks(EH-WSNs) can collect energy from the environment and overcome the technical limitations of existing power. Since the transmission distance in a wireless sensor network is limited, the data are delivered to the destination node through multi-hop routing. In EH-WSNs, the routing protocol should consider the power situations of nodes, which is determined by the remaining power and energy-harvesting rate. In addition, in applications such as environmental monitoring, when there are urgent data, the routing protocol should be able to transmit it stably and quickly. This paper proposes an adaptive routing protocol that satisfies different requirements of normal and urgent data. To extend network lifetime, the proposed routing protocol reduces power imbalance for normal data and also minimizes transmission latency by controlling the transmission power for urgent data. Simulation results show that the proposed adaptive routing can improve network lifetime by mitigating the power imbalance and greatly reduce the transmission delay of urgent data.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.925-928
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• 2013

본 논문에서는 기존 유선 전력 전송 기반 에너지 하베스팅 시스템에서 발생되는 문제점을 해결하기 위해 릴레이 기반의 무선 전력 전송 방식을 제안한다. 본 논문에서 제안하는 방식은 에너지 블록 내에 4방향코일을 배치하여 전자기 유도 기반의 무선 전력 전송을 수행할 수 있으며, 전송 신뢰성을 확보하기 위한 릴레이 제어 알고리즘을 통해 송 수신 경로를 확장할 수 있다.

• 한국철도학회논문집
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• 제9권1호
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• pp.1-6
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• 2006

The purpose of this study is to calculate transmission loss of the high speed railway's wall section accurately. Transmission loss measurement of ideal case i.e. the wall in the laboratory condition was carried out in first, which results were compared with those by statistical energy method. Transmission loss values of high speed railway calculated out by experimental method are compared with those from closed form solution. Commercial statistical energy analysis was also used to predict the outside pressure level using those measured transmission loss values. Simple SEA model could estimate reasonable exterior sound pressure level.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권6호
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• pp.1357-1378
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• 2013

Energy constraint of wireless sensor networks makes energy saving and prolonging the network lifetime become the most important goals of routing protocols. In this paper, we propose an Energy Efficient Chain-based Routing Protocol (EECRP) for wireless sensor networks to minimize energy consumption and transmission delay. EECRP organizes sensor nodes into a set of horizontal chains and a vertical chain. Chain heads are elected based on the residual energy of nodes and distance from the header of upper level. In each horizontal chain, sensor nodes transmit their data to their own chain head based on chain routing mechanism. EECRP also adopts a chain-based data transmission mechanism for sending data packets from the chain heads to the base station. The simulation results show that EECRP outperforms LEACH, PEGASIS and ECCP in terms of network lifetime, energy consumption, number of data messages received at the base station, transmission delay and especially energy${\times}$delay metric.

• ETRI Journal
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• 제31권3호
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• pp.348-350
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• 2009

To fit the limited volume and power consumption of the passive radio frequency transmission system of the electronic time fuze, an improved coded mark inversion (CMI) is proposed in this letter. From the performance analysis, the energy transmission efficiency of this encoding method is at least 50% higher than that of CMI and NRZ. Finally, the experiment results show that by adopting this improved CMI, the change of DC voltage through magnetic coupling is lower than 0.2 V when the accuracy of data transmission is above 99.5%.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.435-447
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• 2019

Energy Flow Finite Element Analysis (EFFEA) is a promising tool for predicting dynamic energetics of complicated structures at high frequencies. In this paper, the Energy Flow Finite Element (EFFE) formulation of complicated Mindlin plates was newly developed to improve the accuracy of prediction of the dynamic characteristics in the high frequency. Wave transmission analysis was performed for all waves in complicated Mindlin plates. Advanced Energy Flow Analysis System (AEFAS), an exclusive EFFEA software, was implemented using $MATLAB^{(R)}$. To verify the general power transfer relationship derived, wave transmission analysis of coupled semi-infinite Mindlin plates was performed. For numerical verification of EFFE formulation derived and EFFEA software developed, numerical analyses were performed for various cases where coupled Mindlin plates were excited by a harmonic point force. Energy flow finite element solutions for coupled Mindlin plates were compared with the energy flow solutions in the various conditions.

• 한국정보통신학회논문지
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• 제18권1호
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• pp.183-190
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• 2014

본 논문에서는 다중 채널을 지원하는 무선 센서 네트워크에서 에너지 소비를 줄이기 위하여 우선순위를 기반으로 사용가능한 채널의 수를 달리하는 전송 기법을 제안한다. 센서 네트워크에서는 센서 노드들은 데이터 전송시에 가장 많은 에너지를 소비하고 전송거리가 길수록 더 많은 에너지를 소모한다. 그러므로 먼 거리에서 전송된 패킷의 전송 실패로 인한 재전송은 추가적인 많은 에너지 소모를 유발한다. 이에 본 논문에서는 재전송으로 인한 추가적인 에너지 소모를 줄이기 위해서 전송 거리가 먼 센서 노드들에게 높은 우선순위를 배정하여 안정적인 전송 환경을 제공한다. 높은 우선순위의 수신 데이터를 위해서 사용가능한 채널의 수를 보다 많이 할당한다. 실험의 결과 제안 기법은 연결실패확률과 재전송에 따른 에너지 소모량에서 좋은 성능을 보였다.

• 한국입자에어로졸학회지
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• 제17권2호
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• pp.37-42
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• 2021

Although the installation of droplet protection screen (DPS) is known to prevent droplet transmission, there is still a lack of knowledge in effectiveness of DPS installation to block the airborne transmission. In this study, the prevention ability of DPS against airborne transmission was evaluated according to the DPS height. When the DPS was not installed, the maximum concentration of PM1.0 at the location opposite to infected person was 35% of that at the infected person location. When the DPS was installed, the DPS effectively prevented the airborne transmission, consequently approximately 7% of generated particles were measured at the opposite location from particle generation position (infected person location). The prevention ability of DPS increased with DPS height, the maximum prevention efficiency of 95.1% was obtained when the DPS height was 900mm. Moreover, the speed of airborne transmission was delayed by installation of DPS, and the delay time increased with DPS height.

• 전기전자학회논문지
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• 제22권3호
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• pp.651-657
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• 2018

IEEE 802.11 무선랜은 20MHz부터 160MHz의 전송 대역폭을 지원한다. 일반적으로 전송 시 대역폭이 증가함에 따라 전송속도가 증가하지만, 동시에 단위 주파수당 전송파워가 낮아져 오류율이 증가하고 재전송을 유발할 수 있다. 본 논문에서는 이러한 현상이 전송 에너지 소비에 미치는 영향을 분석하기 위한 수학적 모델링을 수행한다. 그리고, 이를 바탕으로 전송 대역폭을 결정하는 기법을 제시한다. 제시된 기법은 기존 전송 결과를 기반으로 대역폭별 오류율을 추정하고 이를 바탕으로 대역폭별 에너지 소비 테이블을 업데이트 후 이들 간의 비교를 통해 최적 대역폭을 결정한다. VoIP 트래픽을 가정한 시뮬레이션을 통해 다양한 환경에서 제안한 기법의 에너지 소비 성능을 평가한다.

• Tribology and Lubricants
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• 제21권5호
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• pp.227-235
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• 2005

This paper presents a tribological study on the failure cases of automatic transmission components in a passenger car. The automatic transmission system is composed of torque converter, clutch, brake, planetary gear, and valve body controlling oil pressure of an automatic transmission fluid. The most largest influence components in an automatic transmission are a torque converter and clutch plate in which are influenced by a wear and torque converting energy loss. The failure case study of an automatic transmission indicates that the tribological design and maintenance technologies should be considered as a key design concept. This means that the failure and power energy loss come from the friction, wear and a oil leakage of an automatic transmission, which is related to the oil seal and O-ring seal failures.