• 한국정보통신학회논문지
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• 제15권8호
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• pp.1820-1831
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• 2011

본 논문에서는 제한된 에너지 자원을 사용하는 센서 노드에서 실시간 및 비실시간 태스크의 실행이 요구되는 경우, 효율적인 전력 소비와 실시간 태스크의 마감시한 보장 및 비실시간 태스크의 향상된 평균 응답 시간을 제공하는 혼합 태스크 스케줄링 기법을 제안하였다. 제안한 혼합 태스크 스케줄링 기법은 기존 EDF 기반 DVS 스케줄링 기법, FIFO 기반 TinyOS 스케줄링 기법과 태스크 클러스터링 기반의 비선점형 실시간 스케줄링 기법과 성능을 비교하여 그 우수성을 검증하였다.

• 디지털콘텐츠학회 논문지
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• 제7권4호
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• pp.279-285
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• 2006

본 논문에서는 다중경로 페이딩 환경에서 하이브리드 SC/MRC-Lc/L 다이버시티 수신기법을 이용하여 Multi-Carrier DS-CDMA 시스템의 성능 개선을 알아보고, 광대역 DS-CDMA 시스템과 비교, 분석하였다. 결과적으로 Multi-Carrier DS-CDMA 시스템에서 부분대역간섭에 대한 영향은 성능 열화정도가 전체 주파수 대역 중 일부대역에서 만 받았다. 또한, 하이브이드 SC/MRC-Lc/L 다이버시티 수신 시 Multi-Carrier DS-CDMA 시스템은 입력 다이버시티 가지의 수를 적절히 선택함으로서 시스템의 복잡성과 성능 대 비용을 결정할 수 있다.

• 한국경영과학회지
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• 제30권4호
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• pp.27-43
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• 2005

This paper presents a new hybrid data mining technique using error pattern modeling to improve classification accuracy when the data type of a target variable is binary. The proposed method increases prediction accuracy by combining two different supervised learning methods. That is, the algorithm extracts a subset of training cases that are predicted inconsistently by both methods, and models error patterns from the cases. Based on the error pattern model, the Predictions of two different methods are merged to generate final prediction. The proposed method has been tested using practical 10 data sets. The analysis results show that the performance of proposed method is superior to the existing methods such as artificial neural networks and decision tree induction.

• Journal of Power Electronics
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• 제10권3호
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• pp.277-284
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• 2010

This paper presents a novel hybrid carrier based space vector modulation for cascaded multilevel inverters. The proposed technique inherits the properties of carrier based space vector modulation and the fundamental frequency modulation strategy. The main characteristic of this modulation are the reduction of power loss, and improved harmonic performance. The carrier based space vector modulation algorithm is implemented with a TMS320F2407 digital signal processor. A Xilinx Complex Programmable Logic Device is used to develop the hybrid PWM control algorithm and it is integrated with a digital signal processor for hybrid carrier based space vector PWM generation. The inverter offers less weighted total harmonic distortion and it operates with equal electrostatic and electromagnetic stress among the power devices. The feasibility of the proposed technique is verified by spectral analysis, simulation, and experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2687-2689
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• 2004

LMI(Linear Matrix Inequalities) technique is implemented to control hybrid bio system with electric element Biological materials such as muscle and tissue are modeled as electrically passive element in the system. State feedback controller for the hybrid system is designed with constrained control input. The hybrid bio electrical system is characterized in terms of the time and frequency.

• Journal of Electrical Engineering and Technology
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• 제11권3호
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• pp.670-674
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• 2016

The control performance of hybrid PWM inverter using a phase current measurement is presented in this paper. The hybrid PWM technique consists of space vector pulse width modulation (SVPWM) and six-step voltage control operation. The SVPWM is performed to reduce the harmonic components in the low speed region, and the six-step modulation is applied to increase the maximum speed of the IPMSM in the high speed region. Therefore, it is possible to obtain a great performance in both the low speed range and high speed range. However, the six-step modulation cannot be completely implemented, since the inverter that includes the lag-shunt sensing method has an immeasurable current region. In this paper, a quasi-six-step modulation using a modified voltage vector is proposed. The validity and usefulness of the proposed PWM technique is verified by MATLAB/Simulink and experimental results.

• Journal of Communications and Networks
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• 제14권6호
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• pp.703-709
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• 2012

In this paper, we propose a hybrid decode-amplify-forward incremental cooperative diversity protocol using SNR-based relay selection. In the proposed protocol, whenever destination unsuccessfully receives the source's signal, one of relays that exploit hybrid decode-amplify-forward technique is chosen to retransmit the signal. We derive approximate closed-form expressions of outage probability and average channel capacity. Monte-Carlo simulations are presented to verify the theoretical results and compare the performance of the proposed protocol with the direct transmission protocol and conventional incremental relaying protocols.

• 한국멀티미디어학회논문지
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• 제23권1호
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• pp.31-42
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• 2020

During the 4th Industrial Revolution, service platforms utilizing diverse contents are emerging, and research on recommended systems that can be customized to users to provide quality service is being conducted. hybrid recommendation systems that provide high accuracy recommendations are being researched in various domains, and various filtering techniques, machine learning, and deep learning are being applied to recommended systems. However, in a recommended service environment where data must be analyzed and processed real time, the accuracy of the recommendation is important, but the computational speed is also very important. Due to high level of model complexity, a hybrid recommendation system or a Deep Learning-based recommendation system takes a long time to calculate. In this paper, a Cascade-hybrid recommended algorithm is proposed that can reduce the computational time while maintaining the accuracy of the recommendation. The proposed algorithm was designed to reduce the complexity of the model and minimize the computational speed while processing sequentially, rather than using existing weights or using a hybrid recommendation technique handled in parallel. Therefore, through the algorithms in this paper, contents can be analyzed and recommended effectively and real time through services such as SNS environments or shared economy platforms.

• Smart Structures and Systems
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• 제3권4호
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• pp.405-422
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• 2007

A new hybrid damping technique for vibration reduction in flexible structures, wherein a combination of layers of hard passive damping alloys and active (smart) magnetostrictive material is used to reduce vibrations, is proposed. While most conventional vibration control treatments are based exclusively on either passive or active based systems, this technique aims to combine the advantages of these systems and simultaneously, to overcome the inherent disadvantages in the individual systems. Two types of combined damping systems are idealized and studied here, viz., the Noninteractive system and the Interactive system. Frequency domain studies are carried out to investigate their performance. Finite element simulations using previously developed smart beam elements are carried out on typical metallic and laminated composite cantilever beams treated with hybrid damping. The influence of various parameters like excitation levels, frequency (mode) and control gain on the damping performance is investigated. It is shown that the proposed system could be used effectively to dampen the structural vibration over a wide frequency range. The interaction between the active and passive damping layers is brought out by a comparative study of the combined systems. Illustrative comparisons with 'only passive' and 'only active' damping schemes are also made. The influence and the mode dependence of control gain in a hybrid system is clearly illustrated. This study also demonstrates the significance and the exploitation of strain dependency of passive damping on the overall damping of the hybrid system. Further, the influence of the depthwise location of damping layers in laminated structures is also investigated.

• 정보과학회 논문지
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• 제42권7호
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• pp.939-945
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• 2015

2009년을 기점으로, 스마트 기기 시장은 폭발적으로 성장하기 시작했다. 이렇게 보급된 스마트 기기는 사용자에게 다양한 서비스를 제공한다. 그 중, 클라우드 메시징 서비스는 다양한 서비스에 적용되어 사용되고 있다. 클라우드 메시징 서비스는 비동기적으로 메시지를 전달하는 서비스를 의미한다. 클라우드 메시징 서비스를 통해 메시지를 모바일 단말에 전송하는 방식으로는 IP 기반 메시지 전송 기법과 Publish/Subscribe 기법이 있다. 각각의 기법은 메시지 전송을 위해 기본적으로 전송되어야 하는 메시지가 존재한다. 본 논문에서는 기본적으로 전송되어야 하는 메시지 량을 줄이기 위해, 사용자 맞춤형 기반 Hybrid 메시지 전송 기법을 제안한다. Hybrid 메시지 전송 기법에서는 Exponential Moving Average (EMA)와 K-means 알고리즘을 이용해 사용자 맞춤형 분석을 수행하고, 이를 이용해 각 시간대 별로 메시지 전송 기법을 결정하게 된다.