• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.2
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• pp.185-189
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• 2016

Energy-saving heat depending on the country's rise in oil prices up to the product development is regarded as pending issues. Therefore, in recent years, been a continuing research studies developed for increasing the economic efficiency and reliability achieved in effectively using the side of the energy for heating using electrical to address these problems and, in particular made active the technology developed for high performance and renal material becoming. This paper is to study the development of highly efficient induction heating device according to the excellent heat transfer characteristics for energy transfer. Induction heating is used as the phenomenon of electromagnetic induction, such as heat transfer conduction or convection of the existing methods are no different. Medium heat without beating is absorbed directly into the water column switched rapidly, have features that heats evenly. In addition, high-frequency induction heating in a variety of frame designs. Heating element heats only when utilized properly, it is possible to heat the focus.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2B
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• pp.80-90
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• 2006

WSN(Wireless Sensor Network) performs to detect and collect environmental information for one purpose. As examples, WSN is applicable for home network, patient management of a hospital, logistics management, status detection during the war and so on. The WSN is composed of a sink node and several sensor nodes and has a constraint in an aspect of energy consumption caused by limited battery resource. So many required mechanisms in WSN should consider the remained energy condition. A routing mechanism is requested to deliver the collected information to a sink considering energy efficiency in WSN. There have been many researches to establish (a) route(s) for data delivery to the sink. In this paper, we propose establishment of efficient routes. We proposed a uniform routing mechanism together with considering energy efficiency. For the routing, we define energy probability as routing metrics information and Performs suppression of exchange of control messages. In addition, we derive to uniformly consume the energy of the sensor node when establishing the routes. Also, we evaluate and analyze the energy efficiency for proposed mechanisms through NS-2 simulator.

• Journal of IKEEE
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• v.27 no.4
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• pp.411-417
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• 2023

Unmanned aerial vehicle (UAV)-assisted relay has the advantages of ease of deployment, good communication channels, and mobility over traditional terrestrial relay, which greatly improves wireless connectivity. In this paper, we design a UAV-enabled relay network that can utilize radio frequency bands to harvest energy from sources and utilize terahertz (THz) bands to transmit information between secondary transmitters and receivers. Next, we solve the optimal position of the UAV that maximizes the relay channel capacity, and propose an algorithm to design two trajectories of UAV (a straight and an elliptical trajectory) using the derived solution. Numerical results show that the straight trajectory is better in terms of harvested energy and channel capacity.

• Computational Structural Engineering
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• v.9 no.1
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• pp.65-76
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• 1996

The initiation and growth of microcracks or microvoids inside concrete results in the progressive degradation of concrete. This damage processing along processing along with plastic deformation is main cause of nonlinear behavior of concrete. In this study, a continuum damage model of concrete is developed for the analysis of the nonlinear behavior of concrete due to damage and elasto-plastic deformation. Anisotropic damage tensor is used to describe the anisotropy of concrete and hypothesis of equivalent elastic energy is used to define the effective elastic tensor. The damage model including the damage evolution law and constitutive equation is derived with damage variable and damage surface which is defined by damage energy release rate by using the Helmholtz free energy and dissipation potential based on the thermodynamic principles. By adopting a typical plasticity model of concrete, plasticity of concrete is included to this model. Afinite element analysis program implemented with this model was developed and finite element analysis was performed for the analyses of concrete subjected to uniaxial and biaxial loadings. Comparison of the results of analysis with those of experiments and other models shows that the model successfully predicts the nonlinear behavior of concrete.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.439-440
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• 2015

유도가열은 석유, 가스 등의 연료를 사용하는 종래의 설비에 비해 에너지 효율이 높고 관리가 수월하며, 공해를 유발하지 않는 등의 많은 장점으로 인해 산업 분야에 다양하게 응용되어 사용하고 있다. 유도가열의 원리는 전자유도작용을 이용하여 와전류에 의한 손실과, 히스테리시스 손실에 의한 주울열이 발생하는데, 이렇게 발생된 열로 가열하는 방법이며 가열 속응성, 고효율, 친환경, 안정성의 장점을 갖는다. 그러나 공진형 유도가열 인버터 시스템은 환경의 변화나 피가열체의 부식 등의 이유로 공진주파수가 변하는 단점이 있다. 따라서 기존의 단점을 극복하기 위해 자동으로 공진점을 추종할 수 있는 알고리즘을 제안하였고, 기존의 복잡한 제어회로나 알고리즘을 극복하여 시스템의 간소화를 실현하였다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.1
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• pp.47-56
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• 2009

Rock bolts and shotcrete play a crucial role as a main support system in the underground space. Thus, the safety of the underground space may be affected by the defect of rock bolts. In order to evaluate the rock bolt integrity by using non-destructive technique, the transmission method of the guided ultrasonic waves, which are generated by using the piezo disk elements has been successfully performed. The energy generated by the piezo disk elements, however, is not enough for the rock bolts in the field. In addition, the piezo disk elements should be installed at the end of the steel bar during construction of the rock bolts. The purpose of this study is the devolvement of the reflection method, which may generate enough energy, and the application in the field rock bolts. Both laboratory and field tests are carried out. The guided ultrasonic waves with high energy are generated by the hammer impact with the center punch, and the AE sensor is used to measure the reflected guided waves. The received guided waves are analyzed by the wavelet transform. The peak value of the wavelet transform produces the energy velocity, which is used for the evaluation of the rock bolt integrity. The energy velocity increases with an increase in the defect ratio in both laboratory and field rock bolts. This study demonstrates that the hammer-impact reflection method may be a suitable method for the evaluation of the rock bolt in the field.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.54-54
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• 2018

억새(Miscanthus spp.)는 우리나라 등 동아시아가 원산이며 바이오매스량이 많아 바이오에너지 원료작물로서 잠재성이 크기 때문에 2세대 바이오에탄올 생산 원료로 주목을 받고 있고, 축산깔개 및 토양개량제 등으로도 이용되고 있다. 미국과 유럽 등에서는 생태계 교란 방지를 위해 4배체 물억새(M. sacchariflorus)와 2배체 참억새(M. sinensis)의 종간 교잡 이질 3배체인 불임성 억새(M. x giganteous)을 주로 재배하고 있으나, 단일 유전형의 품종으로 병해충과 자연재해에 취약하여 다양한 억새 품종의 개발이 시급한 실정이다. 본 연구는 억새를 재료로 하여 반수체 및 배수체 확보를 통한 배수성 별 특성 평가와 함께 기내배양을 통해 탈분화 및 재분화 시스템을 구축하여 억새의 육종 효율을 높이기 위해서 실시하였다. 억새 종자로부터 캘러스의 유도는 MS배지와 N6배지에 1mg/L 2.4-D를 첨가하였을 때 비배발생 캘러스(nonembryogenic callus)가 유도되었고, N6배지에 3~5 mg/L 2,4-D를 첨가하였을 때 배발생 캘러스(embryogenic callus)가 발생하였다. MS배지보다는 N6배지에서 캘러스 유도율이 높았으며, 식물생장조절제로 2,4-D와 BA 조합처리 보다 2,4-D 단용 처리하였을 때 캘러스 유도율이 더 높았다. 억새 종에 따른 캘러스 유도율은 물억새가 25.2~49.3%, 참억새는 30.3~52.0%였고 거대억새는 62.6~81.1%로 나타났다. 억새 신초 및 줄기로부터의 캘러스 유도율은 물억새가 4.4~17.2%, 참억새는 1.8~7.7%, 거대억새는 15.3~19.9%로 나타나 종자에 비해 매우 낮았다. 미성숙화기로부터의 캘러스 유도는 억새 종에 따른 차이가 없었으며, 3mg/L 2,4-D 첨가 배지에서 캘러스 유도율이 비교적 낮았고(60~80%), 1mg/L와 5mg/L의 2,4-D가 첨가된 배지에서 캘러스 유도율이 높게(90~95%) 나타났다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.2099-2106
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• 2006

In this paper, we addressed the node positioning method for minimizing the sensing energy consumption in wireless sensor networks with adjustable sensing ranges. It is necessary for minimizing the sensing energy consumption to minimize the overlapped sensing area by neighboring nodes. To find a optimal node position, we derived a optimal equations by using the overlapped areas, each node's radiuses and expended angles of opposite neighboring nodes. Based on it, we devised a new node positioning method, called as ASRC(Adjustable Sensing Ranges Control). Unlike existing condition based model, our proposed method was derived from mathematical formula, and we confirmed its validity of sensing energy consumption through simulations.

• 전기의세계
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• v.13 no.1
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• pp.6-15
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• 1964

전기적 기계적 에너지 변환장치로서의 2상유도전동기 braking 현상의 고도적인 dynamics를 정확히 고찰하기 위하여 직류제동과 프라킹(plugging)의 두 현상을 취급하였는데, Larangian 방법에 의하여 도출된 일반화된 전기기계의 운동방정식을 선형변환으로서 .alpha..betha.dq 변환, +-, fb변환 등을 행하여 변형시킨 식에 위 각 현상의 조건을 대입 계산으로 푸는 한편, 적의 비선형성을 갖는 운동방정식을 analog전자계산기에 씨뮤레이트한 후 각 조건 및 정수를 변화시켜 현상을 고찰하여 위 계산으로 얻은 곡선과 비교하였고, 다음에 실제기계의 실험으로 구한 자료를 첨가하였다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1127-1128
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• 2011

실제 운용중인 수도사업장을 대상으로 펌프모터로 가장 많이 쓰이는 유도전동기의 유량제어를 위해 기존의 방법인 밸브개도에 의한 유량제어 방법과 최근기술인 인버터를 이용한 유량제어 방법을 비교분석하여 효율성을 평가 하였고, 최근 전력전자 기술의 발전에 따라 문제시되고 있는 인버터 사용에 따른 고조파를 분석하여 인버터 시스템 도입에 따른 안정성을 평가하였다. 본 연구에서 평가한 펌프모터의 속도 제어를 위한 기존의 방법인 밸브개도에 의한 유량제어 방법과 인버터를 이용한 유량제어 방법에 대한 효율성 및 안정성 평가결과를 바탕으로 인버터시스템을 산업현장에 적극 도입함으로서 에너지 절감에 따른 생산원가 절감 및 수용가의 용수공급 예측을 통한 관망운영의 안정성을 기대할 수 있다.