• 융합신호처리학회논문지
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• 제8권4호
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• pp.279-284
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• 2007

공급 전원의 교체가 어려운 무선 센서 네트워크에서 전력 소모량을 줄이기 위하여 효율적 라우팅에 관한 연구가 다양하게 진행되고 있다. 그 중 라우팅 분야는 현재 동적 클러스터링 방식이 가장 효율적인 방식으로 연구되고 있다. 동적 클러스터링 방식은 클러스터를 구성하는 부분과 데이터를 전송하는 부분으로 구성된다. 데이터를 전송하는 부분의 전력 소모는 크로스오버 영역을 중심으로 전송거리가 가까운 센서 노드는 전력 소모량이 $d^2$에 비례하고, 전송거리가 먼 센서노드는 $d^4$에 비례된다. 그러므로 크로스오버 영역 밖의 먼 거리 전송을 줄이는 것은 중요하다. 본 논문은 동적 클러스터 방식의 데이터 전송 부분에서 전송거리가 크로스오버 영역 밖의 먼 거리 전송을 최소화함으로 전력 소모량을 줄이는 방법을 제안하였다. 이 방식은 데이터 전송에 있어서는 크로스오버 영역 내에 브리지 클러스터를 구축하여 경유하는 방식으로 전송거리와 관계없이 각 노드의 소비전력이 균등하고, 모든 노드의 전체 전력 소모량을 줄이는 방식이다. 이 제안의 타당성을 모의 실험을 통해 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.407-410
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• 2002

As a part of electro-mechanical totally implantable artificial heart, a transcutaneous energy transmission system has been developed. By mutual magnetic induction between the first coil on the skin and the subcutaneously implanted second coil, the system transfers electrical power through the skin. This research aimed a minimizing the size of the implanted part as well as maximizing the transfer efficiency. When an air gap is 1$\sim$2cm, voltage gain and current gain low and it is hard to transfer energy due to large leakage flux. That is, the required input voltage and input current must be large compared with the output voltage and output current, respectively, This paper research the inverter topology and the control method in order to increase the voltage gain and the current gain. For this purpose, this inverter employs double tune to compensate the large leakage inductance of primary and secondary of the transcutaneous transformer. And the output energy of transcutaneous energy transmission system supply for Lithium-ion battery charger.

• Medical Lasers
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• 제10권4호
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• pp.214-219
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• 2021

Background and Objectives To evaluate the difference in near-infrared (810 nm) laser energy transmission through teeth with and without cracks. Materials and Methods Extracted teeth were sectioned and examined visually for the presence of cracks with the aid of photographs and a trans-illuminator. Fourteen sections, each with cracks (Group A) and no cracks (Group B) were identified and placed 15 mm from the tip of a 300 micron fiber, prior to activation with an 810 nm diode laser (0.1W, 50 ms interval,100 ms duration). A power meter positioned behind the tooth recorded the average energy that was transmitted through the samples. Unpaired t-test analysis was used to determine if the tooth sections with cracks allowed higher power passage compared to sound teeth. Results The mean power recording for the cracked teeth (Group A) was significantly greater (p = 0.0005) than that for the non-cracked teeth (Group B). Conclusion Within the limitations of this study, it is evident that significantly higher laser energy passes through teeth with cracks in comparison to teeth without cracks. A recent clinical study has also shown that lasers could be used to assess symptomatic cracked teeth. Hence, further research is required to determine the relative increase in energy required to identify symptomatic cracked teeth.

• 문화기술의 융합
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• 제10권3호
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• pp.879-884
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• 2024

무선 센서 네트워크 기술은 4차 산업혁명의 발전과 함께 중요성이 더욱 부각되고 있다. 이에 따라 LEACH, PEGASIS, 그리고 EEACP와 같은 다양한 프로토콜이 개발되어 에너지 효율을 높이는 시도가 이루어지고 있다. 그러나 EEACP 프로토콜은 여전히 전송 간 에너지 소모 측면에서 개선의 여지가 남아있다. 특히 데이터 수신 각 설정과 관련된 비효율적인 경로로 인해 네트워크의 생존성이 저하될 수 있다. 제안하는 A-EEACP 프로토콜은 이러한 문제를 해결하기 위해 싱크 노드를 중심으로 데이터 전송 방향을 최적화하여 에너지 소모를 줄이고 네트워크의 생존성을 향상시켰다.

• 한국통신학회논문지
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• 제38A권7호
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• pp.571-579
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• 2013

본 논문은 셀룰러 네트워크에서 D2D (device-to-device) 통신을 고려한 시스템의 에너지 효율적인 모드 선택 기법 (mode selection) 및 파워 할당 기법 (power allocation)을 제안한다. 본 논문에서는 각 단말(device)의 에너지 효율성의 합 측면에서 에너지 효율성 (energy efficiency)을 분석한다. 먼저, 각 단말의 모든 가능한 모드에 대해 에너지 효율을 최대화하는 전송 파워를 계산한다. 제안하는 파워 할당 기법은 시스템 용량 측면에서 최적은 아니지만, 에너지 효율성 측면에서 최적의 성능을 보인다. 제안하는 전송 파워 할당 기법을 기반으로, 모든 가능한 모드에 대해 에너지 효율성을 구한다. 다음 단계로, 모든 가능한 모드 중에서 최대의 에너지 효율성을 갖는 모드를 구하며 동시에 해당 모드의 할당 전송 파워를 도출할 수 있다. 제안 기법은 에너지 효율성 측면에서 최적의 성능을 보이며, 기존 기법에 비해 월등한 성능을 보인다.

• International Journal of Computer Science & Network Security
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• 제22권9호
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• pp.389-395
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• 2022

A Mobile Sensor Network is widely used in real time applications. A critical need in Mobile Sensor Network is to achieve energy efficiency during routing as the sensor nodes have scarce energy resource. The nodes' mobility in MWSN poses a challenge to design an energy efficient routing protocol. Clustering helps to achieve energy efficiency by reducing the organization complexity overhead of the network which is proportional to the number of nodes in the network. This paper proposes"EERA: Energy Efficient Routing Algorithm for Mobile Sensor Network" is divided into five phases. 1, Cluster Formation 2.Cluster head and Transmission head selection 3.Path Establishment / Route discovery and 4,Data Transmission. Experimental Analysis has been done and is found that the proposed method performs better than the existing method with respect to four parameters.

• Carbon letters
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• 제26권
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• pp.61-65
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• 2018

Comprehensive calculations of the Rh decoration effect on zigzag CNTs with n ranging from 7 to 12 were conducted in this work to understand the effect of Rh doping on geometric structures and electronic behaviors upon metallic and semiconducting CNTs. The obtained results indicated that Rh dopant not only contributes to the deformation of C-C bonds on the sidewall of CNTs, but also transforms the electron distribution of related complexes, thereby leading to a remarkable increase of the conductivity of pure CNTs given the emerged novel state within the energy gap for metallic CNTs and the narrowed energy gap for semiconducting CNTs. Our calculations will be meaningful for exploiting novel CNT-based materials with better sensitivity to electrons and higher electrical conductivity compared with pure CNTs.

• 소음진동
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• 제8권6호
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• pp.1053-1061
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• 1998

In this paper. the power flow analysis(PFA) method is applied to the prediction of the vibrational energy density and intensity of coupled co-planar plates. To cover the energy transmission and reflection at the joint of the plates. the wave transmission approach is Introduced with the assumption that all the incident waves are normal to the joint. By changing the frequency ranges and internal loss factors. we have obtained the reliable PFA results. and compared them with the analytical exact solutions.

• Journal of information and communication convergence engineering
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• 제10권1호
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• pp.21-26
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• 2012

As the new requirements for wireless sensor networks are emerging, real-time communications is becoming a major research challenge because resource-constrained sensor nodes are not powerful enough to accommodate the complexity of the protocol. In addition, an efficient energy management scheme has naturally been a concern in wireless sensor networks for a long time. However, the existing schemes are limited to meeting one of these two requirements. To address the two factors together, we propose real-time communications with two approaches, a protocol for satisfied conditions and one for unsatisfied. Under the satisfied requirement, existing real-time protocol is employed. On the other hand, for the unsatisfied requirement, the newly developed scheme replaces the existing scheme by adjusting the transmission range of some surplus nodes. By expanding the transmission range, the end-to-end delay is shortened because the number of intermediate nodes decreases. These nodes conserve their energy for real-time communications by avoiding other activities such as sensing, forwarding, and computing. Finally, simulation results are given to demonstrate the feasibility of the proposed scheme in high traffic environments.

• 한국소음진동공학회논문집
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• 제20권9호
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• pp.856-862
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• 2010

In this paper, the power flow analysis(PFA) method was developed to predict the vibrational responses of coupled co-planar orthotropic plates in frequencies ranging from medium to high. To cover the power transmission and reflection at the joint of the orthotropic plates, the wave transmission approach is applied with the assumption that all the incident waves are normal to the joint. Through numerical analyses, the power flow energy density and intensity fields of coupled co-planar orthotropic plates were compared with those of classical modal solutions by changing the frequency and internal loss factor, and they show good agreement in terms of the global decay and the attenuation patterns of the energy density.