• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2000년도 하계종합학술대회논문집
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• pp.49-52
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• 2000

In this paper we have developed an image security system based on Internet Web in order to overcome the problem of existing systems that use the dedicated network. The developed system resolves the safety problem of the centralized control model by adapting the distributed control model based on Web, and has the functions of remote control and automatic monitoring for grouped multiple sites on Web browser. And the system can operate various computers or operating system because it's operating software was designed by the concepts of Java Virtual Machine and Virtual Instrument. Also, our system has not need of additional cost for network construction by using Internet and can greatly improve the managemental efficiency of system because the maintenance and publishing of software updates can be performed through Web Server.

• 한국정보통신학회논문지
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• 제19권2호
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• pp.414-421
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• 2015

본 논문에서는 두 사람의 합쳐진 심전도 신호를 분리하여 개인의 심전도 신호로 복원하는 방법을 제안한다. 합쳐진 심전도 신호를 분리하기 위해, 두 사람의 평균 심전도 신호를 사전에 측정하여 가지고 있다고 가정한다. 평균 심전도 신호는 합쳐진 심전도 신호에서 개인의 심전도 신호를 식별하는데 활용될 수 있다. 심전도 신호는 거의 주기 신호의 특성을 가지고 있기 때문에, 자기상관성을 구하면 심박 수의 배수마다 높은 피크 값을 가진다. 이를 통해 각 개인의 심박 주기를 파악할 수 있다. 파악된 두 사람 각각의 주기와 평균 심전도 신호를 이용하여 각각의 R-peak가 어느 사람의 R-peak인지 분류할 수 있다. 즉, 각 사람의 평균심전도 신호를 찾아진 R-peak위치에 배치하여 각 사람의 심전도신호의 추정신호를 만든 뒤 각 신호에 가중치를 얼마나 줘야 하는지 LMSE 최적화를 통해 계산된다. 이 가중치를 기반으로 복원신호를 만들어낸다. 이 복원신호에 에러 신호를 각 복원신호의 비율만큼 더해주는 추가 보정작업을 거침으로써 보다 실질적인 신호로 복원한다. 실험 결과를 통해 합쳐진 심전도 신호가 성공적으로 개인의 심전도 신호로 분리되는 것을 알 수 있다.

• 융합신호처리학회논문지
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• 제16권1호
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• pp.1-8
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• 2015

In many image processing tasks, connected component labeling (CCL) is performed to extract regions of interest. CCL was usually done in a sequential fashion when image resolution was relatively low and there are small number of input channels. As image resolution gets higher up to HD or Full HD and as the number of input channels increases, sequential CCL is too time-consuming to be used in real time applications. To cope with this situation, parallel CCL framework was introduced where multiple cores are utilized simultaneously. Several parallel CCL methods have been proposed in the literature. Among them are NSZ label equivalence (NSZ-LE) method[1], modified 8 directional label selection (M8DLS) method[2], and HYBRID1 method[3]. Soh [3] showed that HYBRID1 outperforms NSZ-LE and M8DLS, and argued that HYBRID1 is by far the best. In this paper we propose an improved hybrid parallel CCL algorithm termed as HYBRID2 that hybridizes M8DLS with label backtracking (LB) and show that it runs around 20% faster than HYBRID1 for various kinds of images.

• Smart Structures and Systems
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• 제4권4호
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• pp.429-438
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• 2008

The aim of this paper is to define the required measurements and processing tools necessary for developing a maintenance approach applied to rotating machines in the presence of multiple faults. The system responses measured were accelerations and transmission errors. Acceleration measurements provide most of the information on bearing conditions, while transmission error measurements provide pertinent information on gear conditions. The measurements were carried out for several operating conditions (loads and speeds). System responses were processed in several analyzing domains (Time, Spectrum, and Cepstrum domains). The approach developed enables the detection and identification of combined faults and it can be applied to other types of rotating machines once the critical elements and their associated faults have been defined.

• Journal of Information Processing Systems
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• 제17권6호
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• pp.1083-1096
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• 2021

Compressed sensing-based matching pursuit algorithms can estimate the sparse channel of massive multiple input multiple-output systems with short pilot sequences. Although they have the advantages of low computational complexity and low pilot overhead, their accuracy remains insufficient. Simply multiplying the weight value and the estimated channel obtained in different iterations can only improve the accuracy of channel estimation under conditions of low signal-to-noise ratio (SNR), whereas it degrades accuracy under conditions of high SNR. To address this issue, an improved weighted matching pursuit algorithm is proposed, which obtains a suitable weight value u_op by training the channel data. The step of the weight value increasing with successive iterations is calculated according to the sparsity of the channel and u_op. Adjusting the weight value adaptively over the iterations can further improve the accuracy of estimation. The results of simulations conducted to evaluate the proposed algorithm show that it exhibits improved performance in terms of accuracy compared to previous methods under conditions of both high and low SNR.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2007년도 춘계학술발표대회
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• pp.1310-1312
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• 2007

Throughput improvement problem in wireless mesh network can be alleviated by equipped mesh router with multiple radios tuned into orthogonal channels. However, some links on the same channel also can be activated concurrently if the Signal-to-Noise and Interference Ratio (SNIR) at their receiver endpoints is not lower than the threshold. We propose a greedy algorithm to investigate the problem of how to schedule a set of feasible transmission under physical interference model by using the spatial time-division multiple-access (STDMA) scheme. We also consider the fairness in scheduling to prevent some border nodes from starvation. We evaluate our algorithms through extensive simulation and the results show that our algorithms can achieve better aggregate throughput and fairness performance than 802.11 standard.

• 한국음향학회지
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• 제14권2호
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• pp.92-100
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• 1995

본 연구에서는 결함이 있는 볼베어링을 모델링하여 결함의 형태별로 진동분석을 하였다. 진동측정은 단일결함과 복합결함이 있는 볼베어링에 대하여 결함위치와 회전속도 변화에 대한 진동신호를 측정하고, 신호 성분들은 고주파 공진기법을 이용해 FFT시켰다. 실험결과 단일결함과 복합결함이 있을 때 결함으로 인해 발생하는 주파수는 결함 특성 주파수와 그 배수의 고조파 성분 피크들이 나타남을 확인하였다. 고주파 공진기법을 이용한 신호처리는 결함의 유무 뿐만 아니라 결함의 부위도 진단이 가능함을 알 수 있었다.

• Journal of Ubiquitous Convergence Technology
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• 제2권2호
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• pp.59-66
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• 2008

In this study, Software Defined Radio (SDR) technology-based digital filterbank architecture applicable to a multiple-channel processing system such as a wireless mobile communication system using Code Division Multiple Access (CDMA) technology is proposed. The technique includes a micro-processor to redesign Finite Impulse Response (FIR) filter coefficients according to specific system information and to download the filter coefficients to one digital Band Pass Filter (BPF) to reconfigure another system. The feasibility of the algorithm is verified by computer simulation and by implementing a multiple-channel signal generator that is reconfigurable to other system profiles, including those of a Wideband Code Division Multiple Access (WCDMA) system and a CDMA system.

• 한국정보기술학회 영문논문지
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• 제10권1호
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• pp.1-14
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• 2020

Antenna selection is a method to enhance the performance of spatial multiplexing multiple-input multiple-output (MIMO) systems, which can achieve the diversity order of the full MIMO systems. Although various selection criteria have been studied in the literature, they should be adjusted to the detection operation implemented at the receiver. In this paper, antenna selection methods that optimize the post-processing signal-to-noise ratio (SNR) and eigenvalue are considered for the lattice reduction (LR)-based receiver. To develop a complexity-efficient antenna selection algorithm, the incremental selection strategy is adopted. Moreover, for improvement of performance, an additional iterative selection method is presented in combination with an incremental strategy.

• 대한전자공학회논문지TE
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• 제42권2호
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• pp.1-6
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• 2005

Ryu 등은 선형 선배열센서를 이용하여 표적의 방위각 궤적을 추적하는 알고리즘을 제안하였다. Ryu 등이 제안한 방위각 추적 알고리즘은 선형 선배열센서의 출력신호를 이용하여 신호부공간을 추정하고, 추정된 신호공간으로부터 각 표적의 방위각 이노베이션을 구하며, 이렇게 구한 방위각 이노베이션을 각 표적에 할당된 칼만필터의 입력으로 사용함으로써 표적의 방위각 궤적을 추적한다. 이러한 구조를 가지는 Ryu의 방위각 추적 알고리즘은 별도의 데이터연관 필터가 필요 없으며 효율적이라는 장점을 가지고 있다. 그러나 Ryu의 방위각 추적 알고리즘은 선형 선배열센서를 사용하는 환경에서 제안되었기 때문에 임의형상 배열센서에 적용하기에는 부적합하다. 배열센서를 사용하는 여러 응용분야에서 배열센서를 구성하는 센서들은 실제로 위치오차를 가지며, 배열센서는 임의형상 배열센서가 된다. 본 논문에서는 Ryu 알고리즘의 장점과 추적 성능을 그대로 유지하면서 임의형상 배열센서에 적용할 수 있는 방위각 추적 알고리즘을 제안한다.