• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.2
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• pp.93-102
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• 2010

The FMCW(Frequency Modulation Continuous Wave) radar possesses range-velocity ambiguity to identify the correct combination of beat frequencies for each target in the multi-target situation. It can lead to ghost targets and missing targets, and it can reduce the detection probability. In this pap er, we propose an effective identification algorithm for the correct pairs of beat frequencies and the signal processing hardware architecture to effectively support the algorithm. First, using the correlation of the detected up- and down-beat frequencies and Doppler frequencies, the possible combinations are determined. Then, final pairing algorithm is completed with the power spectrum density of the correlated up- and down-beat frequencies. The proposed hardware processor has the basic architecture consisting of beat-frequency registers, pairing table memory, and decision unit. This method will be useful to improve the radar detection probability and reduce the false alarm rate.

• Journal of Information Technology Applications and Management
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• v.24 no.1
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• pp.1-10
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• 2017

Recently, the problem of plagiarism has emerged as a big social issue because not only literature but also thesis become the target of plagiarism. Even the government requires conformation for plagiarism of high-ranking official's thesis as a standard of their ethical morality. Plagiarism is not just direct copy but also paraphrasing, rewording, adapting parts, missing references or wrong citations. This makes the problem more difficult to handle adequately. We propose a plagiarism detection scheme called a bit signature in which each unique word of document is represented by 0 or 1. The bit signature scheme can find the similar documents by comparing their absolute and relative bit signatures. Experiments show that a bit signature scheme produces better performance for document copy detection than existing similar schemes.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.2
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• pp.429-449
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• 1996

An objective definition of the anomaly is not avaliable and most investigators define the term differently or fail to describe their criterion. Because dental anomaly may lead to many complications, early detection and diagnosis of dental anomalies are essential steps in the evaluation of the child patient and in treatment planning. These procedures require detailed medical and dental histories, through clinical examination and the use of radiographs. So, this study was designed to find out the prevalence of dental anomalies. The clinical and roentgenographic examination was undertaken for 8,054 children at age from 0 to 15 years and statistical analysis was done. The results were as follows : 1. Among the examined subjects, 2,134 subjects(26.5%) showed dental anomalies. The prevalence of individual dental anomalies were as follows : supernumerary teeth 15.6%, congenitally missing teeth 6.6%, fusion 2.2%, odontoma 0.35%, microdontia 1.2%, macrodontia 0.05%, gemination 0.22%, talon cusp 0.36%, dens evaginatus 0.24%, dens invaginatus 0.15%, dilaceration 0.27%, taurodontism 0.09%, abnormal tooth position 1.7%, natal & neonatal teeth 0.92%, amelogenesis imperfecta 0.01%. 2. Significant correlations between the groups with individual dental anomalies were as follows : between group I and other groups, there was negative correlation, especially group I and group II. And the correlation coefficient between male and female showed differences. 3. For the supernumerary teeth group, the prevalence of male was higher than female(p<0.001). While for the congenitally missing teeth, macrodontia, microdontia, abnormal tooth position group, the prevalence of female was greater than male(p<0.001). 4. For the congenitally missing teeth group, the mandibular primary lateral incisor showed the highest incidence in primary dentiton, while mandibular lateral incisor in permanent dentition. In the mandible(72.5%), this site showed higher prevalence than in maxilla. In the case with deciduous congenitally missing teeth, the prevalence of successive permanent congenitally missing teeth was about 33.9%, the incidence was highest in mandibular lateral incisors. 5. Most supernumerary teeth existed on middle area and showed inverted position and unerupted state. In addition, supernumerary teeth showed higher incidence on maxilla (99.3%). 6. In the case with deciduous fused teeth, the prevalence of successive permanent congenitally missing teeth was 39.9%, while that of successive permanent fused teeth was 2.7%. And the highest rate of the prevalence (40.3%) appeared in fusion of mandibular deciduous lateral incisor and canine. 7. In the case of odontoma, the prevalence was higher in maxilla(78.6%) and anterior region(82.7%) than mandible and posterior region.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.371-374
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• 2001

본 논문에서는 움직임 보상을 이용한 Motion-Adaptive De-interlacing Method를 제안 한다. 정확한 움직임 추정을 위해서 Pre-filter로서 EBMF(Edge Based Median Filter)를 사용하며 새로운 Block Matching Method를 제안한다. Temporal Filter로서 Motion Missing Error를 제거하기 위해 입력 영상의 움직임 영역에 따라 각각 다른 임계 값을 적용하는 AMPDF(Adaptive Minimum Pixel Difference Filter)를 적용하였으며 MMD(Maximum Motion Detection)와 SAD(Sum of Difference)를 이용하여 빠른 움직임 영역에서 화질을 향상시켰다. 최종적으로 잘못된 움직임 보상에 기인하는 화질의 열화를 방지하기 위한 Motion Correction Filter를 제안한다.

• Proceedings of the Korea Contents Association Conference
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• 2019.05a
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• pp.179-180
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• 2019

Nowadays, clustering algorithm is considered as a promising solution for lacking human-labeled and massive data of social media sites in numerous machine learning tasks. Many researchers propose disaster event detection systems have ability to determine special local events, such as missing people, public transport damage by clustering similar tweets and hashtags together. In this paper, we try to extend tweet hashtag feature definition by applying word embedding. The experimental results are described that word embedding achieve better performance than the reference method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.6
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• pp.2735-2751
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• 2020

The emergence of Software Defined Networking (SDN) overcomes the limitations of traditional networking architectures. There are some advantages in SDN which are centralized global network view, programmability, and separation of the data plane and control plane. Due to the limitation of data plane storage capacity in SDN, it is necessary to process the redundancy rules of switch. In this paper, we propose a method for active detection and processing of redundant rules. We use the result generated by the customized probe package to detect redundant rules. And by checking the forwarding behavior of probe packets in the data plane, the redundancy rules are further processed. Furthermore, in order to quickly check the dynamic networks, we propose an incremental algorithms for rapidly evolve the network strategies. We conduct simulation experiments on Matlab to verify the feasibility of the algorithm. The influence of some parameters on the result are discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.11
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• pp.918-925
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• 2007

In this paper, different criteria fur determining hue change time in the hue detection based transient liquid crystals technique were compared. Results showed that methods utilizing threshold of intensity or saturation gave many missing points and quality of the calculated results were strongly depends on the value of threshold. Wider bandwidth in the hue bandwidth method showed better distribution of calculated hue change time, but induced ambiguity in the hue change time. In the time-hue curve fitting method, the distribution of evaluated hue change time was smooth and reasonable, and, by the nature of curve fitting, the noise effect on the hue was successfully considered in calculating of the hue change time. Compared to other methods, it is expected that the time-hue curve fitting method would provide better and accurate hue change time in the hue detection based transient liquid crystals technique.

• Journal of Internet Computing and Services
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• v.18 no.5
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• pp.39-46
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• 2017

In this paper, we proposes method of vanishing point detection using orthogonality of vanishing point, under the "Manhattan World" assumption that the structure of the city is mostly grid and vanishing point are orthogonal to each other. The feature that the vanishing point are orthogonal to each other can be useful for inferring the missing point that are not detected among the three vanishing point, and prevent the vanishing point detected close to the other vanishing point. In this paper, we detect Vertical vanishing point through statistical approach and detect Horizontal and Front vanishing point through structural approach. Experimental results show that the proposed method improves the detection accuracy of the vanishing point compared with the existing method.

• Speech Sciences
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• v.10 no.1
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• pp.95-105
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• 2003

This paper describes a new parameter for voice activity detection which serves as a front-end part for automatic speech recognition systems. The new parameter called run-ratio is derived from the runs test statistic which is used in the statistical test for randomness of a given sequence. The run-ratio parameter has the property that the values of the parameter for the random sequence are about 1. To apply the run-ratio parameter into the voice activity detection method, it is assumed that the samples of an inputted audio signal should be converted to binary sequences of positive and negative values. Then, the silence region in the audio signal can be regarded as random sequences so that their values of the run-ratio would be about 1. The run-ratio for the voiced region has far lower values than 1 and for fricative sounds higher values than 1. Therefore, the parameter can discriminate speech signals from the background sounds by using the newly derived run-ratio parameter. The proposed voice activity detector outperformed the conventional energy-based detector in the sense of error mean and variance, small deviation from true speech boundaries, and low chance of missing real utterances

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.559-562
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• 2003

In this paper, we introduce a new method detecting thyristor faults of the power converter module in Control Rod Control System. When we control the currents in each coil of Control Rod Drive Mechanism by using the current control method, the current value can follow the current reference despite the faults like the missing phase or the diode acting. Comparing the fault current values with the normal current values, the bad transient characteristics of the abnormal current can make the operations of control rods incorrect. In this case, the information from the current trends cannot be enough to detect the fault occurrence in thyristors. Instead of the coil currents, the state of thyristors can be watched by measuring the coil voltages. In the existing system of Westinghouse type, the ripple detector takes charge of this task. But this detector has some shortcomings in the point of time for fault detection, we come to devise a new fault detection method solving the problems which belong to the ripple detector.