• Journal of the Korean Data and Information Science Society
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• 제26권2호
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• pp.525-533
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• 2015

Modern production process is a very complex structure combined observations which are correlated with several factors. When the error signal occurs in the process, it is very difficult to know the root causes of an out-of-control signal because of insufficient information. However, if we know the time of the change, the system can be controlled more easily. To know it, we derive a maximum likelihood estimator (MLE) of the change point in a process when observations are from a multivariate IMA(1,1) process by monitoring residual vectors of the model. In this paper, numerical results show that the MLE of change point is effective in detecting changes in a process.

• 대한의용생체공학회:의공학회지
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• 제13권1호
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• pp.1-8
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• 1992

In the field of prosthesis arm control, the pattern classification of the EMG signal is a required basis process and also the estimation of force from collected EMG data is another necessary duty. But unfortunately, what we've got is not real force but an EMG signal which contains the information of force. This is the reason why we estimate the force from the EMG data. In this paper, when we handle the EMG signal to estimate the force, spatial prewhitening process is applied from which the spatial correlation between the channels are removed. And after the orthogonal transformation which is used in the force estimation process, the transformed signal Is inputed into the probabilistic model for pattern classification. To verify the different results of the multiple channels, SNR(signal to noise ratio) function is introduced.

• 한국정보전자통신기술학회논문지
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• 제2권3호
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• pp.17-22
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• 2009

본 연구의 목적은 운동역학 및 정형외과 등에서 많이 사용하는 근전기록장치의 범용 신호처리 소프트웨어를 개발하는 것이다. 개발한 신호처리 소프트웨어는 임상, 재활, 인간공학 및 스포츠 등에서 많이 사용하는 근전기록장치에 범용적으로 사용 가능하다. 모니터링, 주파수 분석, 제로 크로싱 및 비교 분석 등의 신호처리가 자동으로 처리 가능한 각각의 모듈을 개발하였다. 그리고 연속적인 모니터링, 분석이 쉬운 출력물, 사용이 쉬운 UI가 가능하도록 개발하였다. 개발된 신호처리 소프트웨어는 임상, 재활, 인간공학 및 스포츠 등의 여러 분야에 사용 가능하도록 개발하였고, 작동 실험 결과에서 볼 수 있듯이 측정된 근전신호는 좋은 특성 결과를 보였다. 본 연구에서 개발된 신호처리 소프트웨어는 신경외과 및 정형외과 등에서 사용하는 근전기록장치의 소프트웨어로 적용 가능할 것으로 판단된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권8호
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• pp.1913-1925
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• 2012

In order to efficiently utilize limited radio resources, resource allocation schemes in OFDMA-based wireless networks have gained intensive attention recently. Instead of improving the throughput performance, the utility is adopted as the metric for resource allocation, which provides reasonable methods to build up the relationship between user experience and various quality-of-service (QoS) metrics. After formulating the optimization problem by using a weighted bipartite graph, a modified bipartite matching method is proposed to find a suboptimal solution for the resource allocation problem in OFDMA-based wireless systems with feasible computational complexity. Finally, simulation results are presented to validate the effectiveness of the proposed method.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2016년도 제53차 동계학술대회논문집 24권1호
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• pp.321-322
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• 2016

본 논문에서는 수배전반에서 부하 설비 또는 외부의 영향을 확인할 수 있는 장치 및 보호설비가 설치되어 있으나 자체 사고를 신속히 검출하고 판단할 수 있는 기술의 확보를 위하여 해상도가 낮은 저가의 열화상 센서에 고속 DSP(Digital Signal Process)를 사용하여 영상 처리 기법인 이차원 보간법 기술을 이용하여 아크플래시에 의해 발생되는 열 특성을 검출하고 검출된 데이터를 전송하여 전기화재사고를 미연에 방지할 수 있는 장치 개발을 위한 기초 특성 연구를 수행하였다.

• 제어로봇시스템학회논문지
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• 제4권4호
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• pp.506-516
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• 1998

In this paper, an algorithm is proposed to detect the malfunction of plasma-etching characteristics using EPD signal trajectories. EPD signal trajectories offer many information on plasma-etching process state, so they must be considered as the most important data sets to predict the wafer states in plasma-etching process. A recent work has shown that EPD signal trajectories were successfully incorporated into process modeling through critical parameter extraction, but this method consumes much effort and time. So Principal component analysis(PCA) can be applied. PCA is the linear transformation algorithm which converts correlated high-dimensional data sets to uncorrelated low-dimensional data sets. Based on this reason neural network model can improve its performance and convergence speed when it uses the features which are extracted from raw EPD signals by PCA. Wafer-state variables, Critical Dimension(CD) and uniformity can be estimated by simulation using neural network model into which EPD signals are incorporated. After CD and uniformity values are predicted, proposed algorithm determines whether malfunction values are produced or not. If malfunction values arise, the etching process is stopped immediately. As a result, through simulation, we can keep the abnormal state of etching process from propagating into the next run. All the procedures of this algorithm can be performed on-line, i.e. wafer to wafer.

• 한국정보통신학회논문지
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• 제17권8호
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• pp.1784-1789
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• 2013

본 논문에서는 성긴 신호의 복원을 위하여 기존의 직교매칭퍼슛 (orthogonal matching pursuit, OMP) 기술을 보완한 Parallel OMP (POMP) 기법을 제안하고 성능을 분석한다. POMP알고리즘의 과정은 간단하지만 기존 OMP와 비교하여 더 좋은 성능을 보이는 알고리즘이다. POMP 는 첫 번째 반복 과정에서 관찰 행렬과 상관도가 높은 인덱스 집합을 여러 개 선택한다. 선택된 각각의 인덱스를 첫 번째 인덱스로 하는 각각의 POMP 블록에서 OMP 알고리즘 기법이 병렬적으로 동작한다. 마지막으로 신호 복원을 위해 가장 작은 잔류 오차(residual)를 갖는 POMP블록의 인덱스 집합을 선택한다. 컴퓨터 시뮬레이션을 통해 제안된 POMP가 기존의 신호 복원 기술에 비하여 완벽복원비율과 평균 제곱 오차 (MSE) 측면에서 좋은 성능을 보임을 확인하였고, 이미지복원에 있어서는 눈으로 확인 가능할 정도의 성능 개선을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권1호
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• pp.45-61
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• 2010

In the communication channel, the received signal is affected by many factors that can cause errors. These effects mean that received signal strength (RSS) based methods incur more errors in measuring distance and consequently result in low precision in the location detection process. As one of the approaches to overcome these problems, we propose using direction calibration to improve the performance of the RSS-based method for distance measurement, and sequentially a weighted least squares (WLS) method using reliability factors in conjunction with a conventional RSS weighting matrix is proposed to solve an over-determined localization process. The proposed scheme focuses on the features of the RSS method to improve the performance, and these effects are proved by the simulation results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권2호
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• pp.216-233
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• 2013

Conventional optimization designs of wireless networks mainly focus on spectral efficiency (SE) as a performance metric. However, as diverse media services are emerging, a green wireless network, which not only meets the quality of experience (QoE) requirements for users and also improves energy efficiency (EE), is the most appropriate solution. In this paper, we firstly propose the unit QoE per Watt, which is termed QoE efficiency (QEE), as a user-oriented metric to evaluate EE for wireless networks. We then analyze which is the kind of wireless resource given priority to use under different scenarios to obtain an acceptable QEE. Particularly, power, delay and data-rate related to QoE are separately addressed for several typical services, such as file download, video stream and web browsing services. Next, the fundamental tradeoffs are investigated between QEE and SE for wireless networks. Our analytical results are helpful for network design and optimization to strike a good balance between the users perceived QoE and energy consumption.

• 반도체디스플레이기술학회지
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• 제20권1호
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• pp.18-24
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• 2021

The current settlement and distribution used in theme, background and signal music market other than conventional music is being carried out with either the comprehensive settlement method or the measured meter-rate settlement method in the payment process of collected user fees and compensation depending on the use-permission types. In this settlement and distribution process, however, the reliability issues are often being raised because of the difficulty of tracking rights due to changes in music source rights management information, etc, and the opaque settlement and distribution method itself. This paper proposes a new settlement and distribution platform using a blockchain for the reliable collection and distribution of copyright fees among music user group, monitoring organization group, trust organization group and copyright holders, based on the monitoring information of the theme, background and signal music usage. This platform also provides the transparency in settlement and distribution process among stakeholders through smart contract system.