• International Journal of Internet, Broadcasting and Communication
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• 제10권2호
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• pp.68-73
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• 2018

In recent years, the utilization of the WSN have been rapid. Energy consumption of these networks must be as low as possible. LEACH algorithm is one of the clustering technique. We modify the traditional LEACH algorithm in such way that it will be capable to self-organize large number of nodes and for saving communication resources such as processing time and initiation time. The efficiency of the network highly depends on how the algorithm divides cluster area and selects cluster head. The proposed algorithm can be evaluated through the extensive simulation the result we obtained shows that the life time of a network is increased when energy load is distributed equally among the sensor.

• International Journal of Advanced Culture Technology
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• 제11권1호
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• pp.325-331
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• 2023

In this paper, we propose a mixed neural network structure of CNN and LSTM that can be used to detect or predict odor occurrence, which is most required in manufacturing industry or real life, using odor complex sensors. In addition, the proposed learning model uses a complex odor sensor to receive four types of data such as hydrogen sulfide, ammonia, benzene, and toluene in real time, and applies this data to an inference model to detect and predict odor conditions. The proposed model evaluated the prediction accuracy of the learning model through performance indicators according to accuracy, and the evaluation result showed an average performance of 94% or more.

• Journal of Mechanical Science and Technology
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• 제17권12호
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• pp.1969-1976
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• 2003

In the early phases of the product life cycle, Life Cycle Assessment (LCA) is recently used to support the decision-making for the product concepts, and the best alternative can be selected based on its estimated LCA and benefits. Both the lack of detailed information and time for a full LCA for a various range of design concepts need a new approach for the environmental analysis. This paper explores a new approximate LCA methodology for the product concepts by grouping products according to their environmental characteristics and by mapping product attributes into environmental impact driver (EID) index. The relationship is statistically verified by exploring the correlation between total impact indicator and energy impact category. Then, a neural network approach is developed to predict an approximate LCA of grouping products in conceptual design. Trained learning algorithms for the known characteristics of existing products will quickly give the result of LCA for newly designed products. The training is generalized by using product attributes for an EID in a group as well as another product attributes for the other EIDs in other groups. The neural network model with back propagation algorithm is used, and the results are compared with those of multiple regression analysis. The proposed approach does not replace the full LCA but it would give some useful guidelines for the design of environmentally conscious products in conceptual design phase.

• ETRI Journal
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• 제45권4호
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• pp.570-580
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• 2023

Sensor nodes are the most significant part of a wireless sensor network that offers a powerful combination of sensing, processing, and communication. One major challenge while designing a sensor node is power consumption, as sensor nodes are generally battery-operated. In this study, we proposed the design of a low-power, long range-based wireless sensor node with flexibility, a compact size, and energy efficiency. Furthermore, we improved power performance by adopting an efficient hardware design and proper component selection. The Nano Power Timer Integrated Circuit is used for power management, as it consumes nanoamps of current, resulting in improved battery life. The proposed design achieves an off-time current of 38.17309 nA, which is tiny compared with the design discussed in the existing literature. Battery life is estimated for spreading factors (SFs), ranging from SF7 to SF12. The achieved battery life is 2.54 years for SF12 and 3.94 years for SF7. We present the analysis of current consumption and battery life. Sensor data, received signal strength indicator, and signal-to-noise ratio are visualized using the ThingSpeak network.

• 한국위성정보통신학회논문지
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• 제11권3호
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• pp.123-126
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• 2016

무선 센서 네트워크 하에서 불균일 네트워크의 에너지 효율은 주요 이슈 중의 하나로 고려된다. 불균일 네트워크에서, 개별 노드 초기 에너지의 무작위 분포는 네트워크 불안정을 초래할 수 있다. 따라서 네트워크 상 각 노드의 동작 시간 증가와 에너지 소비의 공평성 유지를 위해서는 적합한 방법이 마련되어야 한다. 본 논문에서는 서로 다른 시나리오의 불균일 네트워크 하의 분산 클러스터링 프로토콜(DCP)의 성능 평가를 보여준다. 본 시뮬레이션 결과는 불균일 네트워크에서의 LEACH 프로토콜 결과와 비교하였다. 추가적으로 불균일 네트워크에서의 시스템 성능을 균일 네트워크와 비교함으로써, 불균형 초기 에너지가 시스템의 개별 노드의 수명에 미치는 영향을 설명한다. 시뮬레이션 수행 결과 균일 및 불균일 네트워크에서 LEACH 프로토콜과의 성능 비교 결과는 DCP의 성능이 모든 경우에 성능 우위에 있음을 나타내었다.

• International Journal of Railway
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• 제6권1호
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• pp.13-25
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• 2013

Railpad prevents damage of the tie and ballast by reducing the impact and high frequency vibration, which occurs when a vehicle load transfers to a tie. But elasticity of the railpad can decrease under vehicle load and over usable period. If that happens, railpad will become stiffer. Increase in stiffness of the railpad also translates into a rise in track maintenance cost because it accelerates the damage of the track. In this study, accelerated heat ageing test was performed to predict an expectable lifetime of the railpad. As a result, it was predicted to be about sixteen years at $25^{\circ}C$ that life time of railpad using NR rubber from Arrhenius relationship. Also, it was predicted to be about thirty-two days at $100^{\circ}C$. At this time, a standard rate of thickness change is approximately within 12%.

• 한국정밀공학회지
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• 제21권11호
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• pp.125-129
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• 2004

For the diagnosis of compressor abnormal condition in air-conditioner, AE signal which is derived from wear condition, compressed air and assembly error is analyzed experimentally. The burst and continuous type AE signal occurred by metal contact and compressed air and AE raw signal of compressors were directly acquired in production line. After extracting samples according to waveforms, Early Life Test(ELT) is conducted and classified to normal and abnormal waveform. The efficient parameters of waveform pattern are investigated in time and frequency domain and the diagnosis algorithm of air-conditioner by Neural Network estimation is suggested.

• International Journal of Computer Science & Network Security
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• 제23권7호
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• pp.119-130
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• 2023

Worldwide organizations use the benefits offered by Cloud Computing (CC) to store data, software and programs. While running hugely complicated and sophisticated software on cloud requires more energy that causes global warming and affects environment. Most of the time energy consumption is wasted and it is required to explore opportunities to reduce emission of carbon in CC environment to save energy. Many improvements can be done in regard to energy efficiency from the software perspective by considering and paying attention on the energy consumption aspects of software's that run on cloud infrastructure. The aim of the current research is to propose a framework with an additional phase called parameterized development phase to be incorporated along with the traditional Software Development Life cycle (SDLC) where the developers need to consider the suggested techniques during software implementation to utilize low energy for running software on the cloud and contribute in green computing. Experiments have been carried out and the results prove that the suggested techniques and methods has enabled in achieving energy consumption.

• 한국인터넷방송통신학회논문지
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• 제17권1호
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• pp.167-172
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• 2017

무선 센서 네트워크의 수명 연장을 위해서 이동 노드를 활용하는 방법들이 제안되었고 최근 드론 기술의 발달로 드론을 활용한 데이터 수집에 관련된 연구들이 활발하게 진행되고 있다. 지상의 무선 센서 네트워크와 드론을 연동할 경우 데이터 수집의 실시간성과 효율성이 높아지는 장점이 있다. 그러나 기존의 연구들은 드론의 에너지 소모를 줄이기 위해 비행 거리를 최소화하는 문제만을 집중하고 있어 노드들의 에너지 소모가 균일하지 못하는 문제를 발생 시킨다. 이러한 불균형적인 노드의 에너지 소모는 각 네트워크의 단절을 가속화하고 이로 인해 드론의 비행거리가 증가하는 문제가 발생한다. 본 논문에서는 이러한 문제를 해결하기 위해 각 클러스터의 내용을 수집하여 드론과 직접 통신하는 랑데부 노드 선정 시 드론의 예상 비행거리와 노드의 수명을 고려한 기법을 제안하였다.

• 정보과학회 논문지
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• 제41권11호
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• pp.958-966
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• 2014

무선 센서 네트워크는 분산처리 환경을 제공해준다. 센서 노드들은 계산 능력, 네트워크 대역폭, 전력 등이 제한된 환경에서 배치되고 스스로 네트워크를 구성하여 수집된 데이터들을 싱크노드로 전송한다. 이런 전형적인 무선 센서 네트워크에서는 네트워크 패킷들 간의 충돌이 발생하며 이로 인해 네트워크 수명이 단축된다. 클러스터링과 네트워크 내부처리는 네트워크 내부의 패킷을 줄여 문제점을 해결한다. 제한된 에너지를 가진 센서 노드가 가능한 오랫동안 동작하게 하는 것이 큰 이슈이기 때문에 많은 연구들이 에너지 절약에 중점을 두고 진행되고 있다. 하지만 본 논문에서는 프로세싱 타임라인에 기반을 둔 협력 처리 모델을 제안한다. 이 모델은 처리의 검증, 총 실행시간의 예측, 무선 센서 네트워크에서 분산 처리에 필요한 최적의 노드 개수의 결정 등을 포함한다. 제안된 모델의 정확성을 실험을 통해 나타내고, 사례 연구로 이 모델이 분산처리 어플리케이션에 사용가능함을 보인다.