• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.5
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• pp.632-639
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• 2012

Ad-hoc networks can be used various environment, which it is difficult to construct infrastructures, such as shadowing areas, disaster areas, war area, and so on. In order to support to considerable and various wireless services, more spectrum resources are needed. However, efficient utilization of the frequency resource is difficult because of spectrum scarcity and the conventional frequency regulation. Ad-hoc networks employing cognitive radio(CR) system that guarantee high spectrum utilization provide effective way to increase the network capacity. In conventional CR based ad-hoc network, it uses constant threshold value to detect primary user signal, so the results become not reliable. In this paper, to solve this problem, we apply adaptive threshold value to the CR based ad-hoc network, and adaptive threshold is immediately changed by SNR(Signal to Noise Ratio). From the simulation results, we confirmed that proposed algorithm has the greatly better detection probabilities than conventional CR based ad-hoc network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1575-1581
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• 2003

As a society has progressed rapidly toward a highly advanced digital information age, a multimedia communication service for acquisition, transmission and storage of image data as well as voice has being commercialized externally and internally. However, in the process of digitalization or transmission of data, noise is generated by several causes, and researches for eliminating those noises have been continued until now. There were the existing FFT(fast fourier transform) and STFT(short time fourier transform) for removing noise but it's impossible to know information about time and time-frequency localization capabilities has conflictive relationship. Therefore, for overcoming these limits, wavelet transform which is presented as a new technique of signal processing field is being applied in many fields recently. Because it has time-frequency localization capabilities it's Possible for multiresolution analysis as well as easy to analyze various signal. And when two wavelet base were designed to form Hilbert transform pair, wavelet pair provide superior performance than the existing DWT(discrete wavelet transform) in data characteristic detection. Therefore in this parer, we removed impulse noise by using adaptive-length median filter and two dyadic wavelet base which is designed by truncated coefficient vector.

• Journal of the Institute of Convergence Signal Processing
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• v.15 no.3
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• pp.91-96
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• 2014

For Sound source direction and separation method, Frequency Domain Binaural Model(FDBM) shows low computational cost and high performance for sound source separation. This method performs sound source orientation and separation by obtaining the Interaural Phase Difference(IPD) and Interaural Level Difference(ILD) in frequency domain. But the problem of reflection occurs in practical environment. To reduce this reflection, a method to simulate the sound localization of a direct sound, to detect the initial arriving sound, to check the direction of the sound, and to separate the sound is presented. Simulation results show that the direction is estimated to lie close within 10% from the sound source and, in the presence of the reflection, the level of the separation of the sound source is improved by higher Coherence and PESQ(Perceptual Evaluation of Speech Quality) and by lower directional damping than those of the existing FDBM. In case of no reflection, the degree of separation was low.

• Korean Journal of Veterinary Research
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• v.42 no.1
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• pp.101-108
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• 2002

The p27 coding region of the SIVmac239 isolate was amplified by PCR and cloned into an expression vector, pMAL-cri, which expressed high levels of the p27 protein from Escherichia coli. The purified p27 protein was used for detection of anti-SIV antibodies with the sera from 11 macaques and 21 marmosets by immunoblot assay of which one macaque was suspicious for the SIV infection. The optimum conditions of ELISA was studied by the check board system with the recombinant purified p27 protein. For the plate coating, 200ng/well of the purified p27 was satisfactory. The conjugate was diluted 1:1000. The sera from the 32 monkeys were negative for the anti-SIV by ELISA.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.2
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• pp.113-118
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• 2011

In this paper, we develop a speaker gender classification technique using collaborative sensor fusion for use in a wireless sensor network. The distributed sensor nodes remove the unwanted input data using the BER(Band Energy Ration) based voice activity detection, process only the relevant data, and transmit the hard labeled decisions to the fusion center where a global decision fusion is carried out. This takes advantages of power consumption and network resource management. The Bayesian sensor fusion and the global weighting decision fusion methods are proposed to achieve the gender classification. As the number of the sensor nodes varies, the Bayesian sensor fusion yields the best classification accuracy using the optimal operating points of the ROC(Receiver Operating Characteristic) curves_ For the weights used in the global decision fusion, the BER and MCL(Mutual Confidence Level) are employed to effectively combined at the fusion center. The simulation results show that as the number of the sensor nodes increases, the classification accuracy was even more improved in the low SNR(Signal to Noise Ration) condition.

• Journal of the Korea Convergence Society
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• v.10 no.10
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• pp.27-31
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• 2019

The purpose of this study is to gather biofilm of unit chair waterline in the laboratory, to analyze microorganisms, to apply the existing draw-off method and the method of using disinfectant, and to compare the change of the number of microorganisms. The water was provided by the waterline of the unitchair, and the gathered samples were cultured with the use of R2A agar plate. Bacterial species separated through the identification of microorganisms were analyzed. To identify the decrease of microorganism for draw-off, samples were gathered in the intervals of 30 seconds, 60 seconds and 120 seconds, and to identify the effect of disinfectant, samples after disinfection were gathered. The quantitative comparison of microorganisms through the gathered samples was done by SPSS program. The number of identified bacteria are 8 species, most of which are gram-negative bacterium, and Sphingomonas type. The rapid decrease of the number of microorganism through draw-off for 60 seconds was confirmed, and microorganisms after disinfection weren't detected right away. Based on the method and result of this study, the water pipe of unit chair, which can be neglected easily, can be managed, so cross infection can be prevented, and systemic management can be possible.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.389-396
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• 2022

Deep Learning is based on a perceptron, and is currently being used in various fields such as image recognition, voice recognition, object detection, and drug development. Accordingly, a variety of learning algorithms have been proposed, and the number of neurons constituting a neural network varies greatly among researchers. This study analyzed the learning characteristics according to the number of neurons of the currently used SGD, momentum methods, AdaGrad, RMSProp, and Adam methods. To this end, a neural network was constructed with one input layer, three hidden layers, and one output layer. ReLU was applied to the activation function, cross entropy error (CEE) was applied to the loss function, and MNIST was used for the experimental dataset. As a result, it was concluded that the number of neurons 100-300, the algorithm Adam, and the number of learning (iteraction) 200 would be the most efficient in deep learning learning. This study will provide implications for the algorithm to be developed and the reference value of the number of neurons given new learning data in the future.

• Journal of fish pathology
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• v.37 no.1
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• pp.79-88
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• 2024

Aeromonas spp. infections have been reported to cause significant economic losses not only in the ornamental fish industry but also in aquaculture. In December 2022-January 2023, an Aeromonas infection occurred on a goldfish in korea, A gram-negative bacterium was isolated from the skin and internal organs of infected goldfish (Carassius auratus). The results showed that the isolate was identified as Aeromonas veronii using 16S rDNA targeted oilgpnucleotide primers, furthermore characteristics of A. veronii was confirmed by enterotoxin gene, infectious experiment, antibiotic resistance. In-vivo pathogenicity of isolates to goldfsh resulted in 100% mortality in challenged host within one week of post experiment injection. As a result of PCR analysis targeting three enterotoxin-encoding genes, cytotoxic enterotoxin (act) was identified in A. veronii isolate in this study. Antimicrobial susceptibility pattern of isolate showed it was to susceptible to most antimicrobial agents tested but resistant to ampicillin, imipenem, meropenem and clindamycin.

• Tuberculosis and Respiratory Diseases
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• v.58 no.2
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• pp.167-173
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• 2005

Background : Airborne particles during Yellow Sand phenomena are known to be associated with the respiratory disease. The purpose of this study was to evaluate the concentration and metal component properties of Yellow Sand particles and compare with airborne microbial concentration and species in non Yellow Sand and Yellow Sand phenomena. Methods : Samplings were carried out in 2002 in Seosan, during non Yellow Sand and Yellow Sand phenomena. Samples were taken using the 8-stage Cascade impactor and metallic elements were analyzed by XRF. Those were culture on the media for bacterial and fungal culture and celline for virus. Results : The concentration of total suspended particulate matter were respectively $80.2{\mu}g/m^3$, $40.3{\mu}g/m^3$ in non Yellow Sand and Yellow Sand phenomena. The concentration of metallic elements such as Ca, Fe, Cu and Zn in Yellow Sand phenomena were higher than its in non Yellow Sand. Two bacteria, Bacillus species and Staphylococcus were grown in two periods. In both periods, several fungal spores(Mucor species, Cladosporum, Alternaria, Aspergillus, Penicillium, and Alternaria species) were identified. The differences of bacteria and fungus species not observed in Yellow Sand and non Yellow Sand. Any viruses were not isolated in between both periods. Conclusions : The concentration of total suspended particulate matter and some metallic elements in Yellow Sand phenomena were higher than its in non Yellow Sand. The difference of bacteria and fungus species was not observed in non Yellow Sand and Yellow Sand phenomena.

• Tuberculosis and Respiratory Diseases
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• v.63 no.4
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• pp.331-336
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• 2007

Background: Although pulmonary tuberculosis (TB) is a respiratory disease, the presence of Mycobacterium tuberculosis (Mtb) DNA or Mtb itself has been reported in the peripheral blood (PB) of several patients with pulmonary TB. Additionally, it was recently announced that active pulmonary TB patients donated PB, and that this blood was then transfused to other individuals in Korea. Methods: Sixty-nine patients with bacteriologically-confirmed pulmonary TB (35), non-tuberculous mycobacterial (NTM) lung disease (6), and other lung diseases (28) were enrolled in this study, which was conducted to determine if Mtb DNA could be detected in the PB by PCR. In addition, 10 pulmonary TB patients with high-burden bacilli were also enrolled in this study for the culture of Mtb in PB. Results: PCR detected the presence of Mtb in 22.8% (8/35) of the pulmonary TB patients, in 16.7% (1/6) of the patients with NTM lung disease, and in none of the patients with other diseases (0%). In addition, no Mtb was cultured from the PB of the 10 pulmonary TB patients. Conclusion: Although Mtb DNA was detected in the PB of some patients with pulmonary TB, viable Mtb was not isolated from the PB of those patients, which indicates that patients that viable Mth may not be transmitted via trasfusion of blood of pulmonary TB patients.