• 한국음향학회지
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• 제27권1호
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• pp.26-32
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• 2008

UBSS (under-determined blind source separation)는 BMMR (blind mixing matrix recovery) 과정과 BSR (blind source recovery) 과정으로 구분된다. 일반적으로 이 두 과정은 취득된 데이터의 sparseness를 이용하여 수행되는데, 얼마나 sparseness를 정확히 측정하느냐에 따라 그 성능이 좌우된다. 본 논문에서는 Gini 계수를 이용한 sparseness의 측정 방법을 BSR 과정에 도입하여, $l_1$-노름, $l_q$-노름과 쌍곡탄젠트 (hyperbolic tangent)를 이용하는 측정 방법들과 비교하였으며, 보다 정확한 sparseness 측정과 향상된 BSR 성능을 획득하였다. 이는 컴퓨터 모의 실험을 통하여 검증되었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.585-590
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• 2004

Many machine failures are not detected well in advance due to the masking of background noise and attenuation of the source signal through the transmission mediums. Advanced signal processing techniques using adaptive filters and higher order statistics have been attempted to extract the source signal from the measured data at the machine surface. In this paper, blind deconvolution using the eigenvector algorithm (EVA) technique is used to recover a damaged bearing signal using only the measured signal at the machine surface. A damaged bearing signal corrupted by noise with varying signal-to-noise (s/n) was used to determine the effectiveness of the technique in detecting an incipient signal and the optimum choice of filter length. The results show that the technique is effective in detecting the source signal with an s/n ratio as low as 0.21, but requires a relatively large filter length.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권6호
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• pp.817-824
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• 2016

A simultaneous bidirectional transceiver over a single wire has been developed in a 65 nm CMOS technology for a command and control bus. The echo signals of the simultaneous bidirectional link are cancelled by controlling the decision level of receiver comparators without power-hungry operational amplifier (op-amp) based circuits. With the clock information embedded in the rising edges of the signals sent from the source side to the sink side, the data is recovered by an open-loop digital circuit with 20 times blind oversampling. The data rate of the simultaneous bidirectional transceiver in each direction is 75 Mbps and therefore the overall signaling bandwidth is 150 Mbps. The measured energy efficiency of the transceiver is 56.7 pJ/b and the bit-error-rate (BER) is less than $10^{-12}$ with $2^7-1$ pseudo-random binary sequence (PRBS) pattern for both signaling directions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권5호
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• pp.1929-1950
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• 2020

Reliable and secure data transmission in the application environment assisted by the wireless sensor network is one of the major challenges. Problem like blind forwarding and data inaccessibility affect the efficiency of overall infrastructure performance. This paper proposes routing protocol for forwarding and error recovery during packet loss. The same is achieved by energy and hops distance-based formulation of the routing mechanism. The reachability of the intermediate node to the source node is the major factor that helps in improving the lifetime of the network. On the other hand, intelligent hop selection increases the reliability over continuous data transmission. The number of hop count is factor of hop weight and available energy of the node. The comparison over the previous state of the art using QualNet-7.4 network simulator shows the effectiveness of proposed work in terms of overall energy conservation of network and reliable data delivery. The simulation results also show the elimination of blind forwarding and data inaccessibility.

• 대한방사선기술학회지:방사선기술과학
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• 제41권1호
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• pp.61-66
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• 2018

The recent 3D printing technology is used in various medical, manufacturing, and education fields and is more efficient in terms of production process, time, and cost than existing production. Especially in fracture surgery, interest and research have been focused on improving accuracy, shortening of operation time and recovery time, and reducing reoperation. However, because of the financial and technical problems of the 3D printer and the file conversion program, the 3D printing is made directly at the hospital, and it is not generally used for diagnosis of fracture and surgical research. In this study, to solve those problems, clavicle CT imaging was switched into Osirix Open Source DICOM Viewer, Stereolithography file conversion programs and commercial Terarecon 3D DICOM Viewer, file conversion programs, and then clavicle fracture model was directly made through 3D printer of fused filament fabrication wire additive processing method, and then the accuracy of the shape was compared and analyzed. Clavicle fracture models printed in two methods were blind-tested on clinicians of general hospitals' orthopedics and radiologic technicians with over 10 years of experiences, and then their analysis opinions of resolution reviews were analyzed. The result showed no difference. The 3D printing model with open source DICOM STL file conversion program used was applicable to clinical, so it is considered useful in precision diagnosis of fracture and operation plans.