• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.1-8
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• 2010

Wireless multimedia service through the access to mobile telephone network or data network is a vital part of contemporary life, and the demand for frequency spectrum for new services is expected to explode as the ubiquitous computing proliferate. Cognitive radio is a technology, which automatically recognizes and searches for temporally and spatially unused frequency spectrum, then actively determines the communication method, bandwidth, etc. according to the environment, thus utilizing the limited spectrum resources efficiently. In this paper, we investigate the effects of imperfect sensing, misdetection and false alarm, on the primary and secondary users' spectrum usage through the analysis of continuous time Markov Chain. We analyzed the effects of the parameters such as sensing error, offered load on the system performance.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.4
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• pp.441-455
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• 2015

In the present study, a face safety monitoring system was developed that will enable judging collapse risks on faces during tunnel construction to secure workers' safety. This system enables detecting abnormal behaviors of faces by analyzing the displacement of faces measured in real time using the x-MR control chart technique. In addition, an algorithm to judge false alarms was developed so that abnormal behaviors of faces and errors occurring in the process of work can be distinguished from each other by comparing the number of measured values exceeding the management criteria and moving range k. The results of the present study are applicable to real-time monitoring of behavior on the face in dangerous ground sections to minimize damage to workers.

• Korean Journal of Culture and Social Issue
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• v.12 no.4
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• pp.77-99
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• 2006

The purpose of this study was to find out the effects of auto-mobile tinting upon driver's cognitive responses and behaviors through two laboratory experiments, a field experiment and a traffic accident data. The results of two laboratory experiments showed that there were higher false alarm responses under the conditions of 65%, 50%, 35% tinting level than thoses under the 100% level condition. It was also shown that the drivers who had bad sight made more missing responses than the drivers who had normal vision. The main results of the laboratory experiment were repliceted through both the field experiment and the survey research of car accidents. The results of this study were discussed in terms of the previous studies performed abroad. We strongly suggested 70% tinting level as a regulation standard for safe driving and the strategies for implementing the regulation rule.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.1
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• pp.19-27
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• 2014

As frequency resource has taken on greater importance, Cognitive Radio(CR) technology has been considered as the solution to improve spectrum utilization by allowing a secondary user to utilize a licensed band when the primary user is absent. So spectrum sensing is significant part of CR for high performance. Recently, cooperative spectrum sensing that secondary users share each sensing results is proposed to improve spectrum sensing accuracy. In this paper, OR rule based cooperative spectrum sensing scheme using reporting error probability which occurs in user to fusion center(FC) channel The simulation results show that proposed scheme mitigates false alarm probability limitation which appears in existing cooperative spectrum sensing scheme by restricting the number of cooperating users using reporting error probability.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.16 no.1
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• pp.90-97
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• 2005

Objectives : The present study was conducted to investigate a correlation of ADS and KEDI-WISC measures. Methods : The data of 91 children were used. On KEDI-WISC, PIQ, VIQ, and 11 subtest measures, and on ADS, 4 variables (ommission error rate, commission error rate, response time mean, and response time deviation) were analyzed. Results : The correlations of Ommission Error Rate and Coding, Digit Span, and Arithmetic, the correlations of Commission Error Rate and Object assembly, Picture Completion, Arithmetic, Digit Span, and Coding, the correations of Response Time Mean and Coding, and the correlations of Response Time Deviation and PIQ, and Coding were significant. Conclusion : ADS variables and several IQ scores are significantly related.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4C
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• pp.476-483
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• 2009

Tracking and detecting targets by the microwave seeker is affected by the clutter reflecting from the earth's surface. In order to detect retreating targets in look-down scenario, which appear in the sidelobe clutter (SLC) region, in the microwave seeker of high pulse repetition frequency (HPRF) mode, it is necessary to understand statistical characteristics of the surface SLC. Statistical analysis of SLC has been conducted for several kinds of the surface using data obtained by the captive flight test of the microwave seeker in the HPRF mode. The probability density function (PDF) fitting is conducted for several kinds and conditions of the surface. PDFs and PDF parameters, which best describe statistical distribution of the SLC power, are estimated. By using the estimated PDFs and PDF parameters, analyses for setting the target-detection thresholds, which give a desired level of target-detection false alarm probability, are made. These analysis materials for statistical characteristics of SLC power and the target-detection threshold can be used in various fields, such as development of a target-detection method, the constant false alarm rate processing.

• Journal of Digital Convergence
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• v.11 no.10
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• pp.731-736
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• 2013

Recently attention deficit of children has caused various social problems. Those children who has symptoms like ADHD (Attention Deficit/Hyperactivity Disorder) has to be provided with methods which can enhance their attention level in a child-friendly way such as 3D games. This paper shows a research on how to measure the level of attention for attention deficit children using their favorite 3D games. Firstly, we speculated on the methods about attention measurement used in the medical area. And then we searched measurement variables which can effectively evaluate the level of attention during a game play time. Secondly, we have conducted experiment whether there exists difference about the value of the measurement variables between the two groups, normal children group and attention deficit children group. Those variables are omission error, commission error, average response time, and standard deviation of response time. Though our experiment has only been limited to visual attention level, four measurement variables revealed mutual differences.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.11 no.2
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• pp.290-296
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• 2000

Objective：This study aims to investigate the cognitive characteristics of clinically referred children with symptoms of inattention, cach as having ADHD, tic disorder, and emotional disorder. Methods：65 boys(38 with ADHD, 17 with Tic disorder, and 10 with Emotional disorder) were individually assessed using the KEDI-WISC(FIQ, VIQ, PIQ) and T.O.V.A.(errors of omission, errors of commission, reaction time, variability, anticipatory response, multiple response), and the results of those tests were analyzed. Results：There was significant difference among three diagnostic groups of the VIQ of KEDIWISC and the reaction time of T.O.V.A. after the correction of the effect of age difference. Conclusion：The findings suggest that the reaction time of T.O.V.A. might be the useful variable to differentiate the ADHD from other psychiatric disorders and the effect of age and IQ difference should be considered carefully to diagnose in clinical setting.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.16 no.2
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• pp.199-210
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• 2005

Objective : Attention deficit hyperactivity disorder(ADHD) affects $5-10\%$ of children in Korea, with more boys and girls being diagnosed. Despite seriousness of ADHD, little is known about its causes. From the current genetic epidemiologic studies, ADHD is known as a heritable disorder. Till now, however, there have been very few genetic studies about ADHD in Korea. The aim of the this study is to examine the association between dopamine transporter gone type 1 and ADHD using case-control design in Korean ADHD probands and normal controls. Materials and Method : Child Psychiatric Genetic research team in Seoul National University Hospital, Clinical Research Institute recruited the ADHD probands using clinical interview/observation, diverse rating scales, and neuropsychological tests. For eliminating phenocopy or ADHD, diagnosis of ADHD was based upon clinical data, psychometric data, and parent/teacher reports. Total 85 ADHD-probands were recruited as final study subjects and independent 100 normal adults participated in this study as control group. For all the ADHD probands, and controls, the 3'-UTR-VNTR polymorphism of DAT1 was analyzed. Based on the DAT1 allele and genotype informations, Chi-square test based on case-control design was performed. Results : As for genetic study, total of 85 probands and 100 controls were included for the genetic analysis. Four different alleles, 350bp (7repeat), 440bp (9repeat), 480bp (10repeat) and 520bp (11repeat) were found in DAT1 gene of study subjects. In case-control analysis, ADHD probands and parents have significantly more 9 repeat allele and 9/10 genotype. Also, The probands with 9repeat allele have more commission errors in ADS. Conclusion : The positive association between ADHD and DAT1 gene was replicated in this report like other previous results for caucasian children and Korean children with ADHD. There are ongoing studies on other candidate genes such as DRD4 and DRD5 and it would be required to explore the association of these candidate genes in Korean children with ADHD. These ongoing genetic research will contribute to the understanding of heterogenous genetic and environmental etiologies of ADHD phenotype, which will lead to the development of more comprehensive treatment and preventive interventions for ADHD.

• Korean Journal of Health Psychology
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• v.16 no.3
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• pp.557-575
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• 2011

This study tried to examine the characteristics of attention deficits in patients with Obstructive Sleep Apenea(OSA) with different age levels, and to examine which indices of polysomnograms might be related to the indices of attention deficits in OSAs. Two age-level groups and a normal control group were subjected to two computerized attention tests, including a continuous performance test(CPT) and a change blindness task(CBT). In addition, the three groups were subjected to a Polysomnography to extract several sub-indicators of polysomnogram, and an Epworth Sleepiness Scale which measures subjective sleepiness. As results, the OSAs showed significantly more omission and commission errors in CPT, and they showed lower accuracy in CBT compared to the normal group. The results of a correlational analysis showed that attention deficits in OSA are significantly correlated with arterial oxygen saturation among sub-indicators of polysomnograms. In conclusion, OSAs seems to be less attentive, having difficulties in response inhibition, and having deficiencies in noticing important environmental changes. Age seems to make these deficiencies even worse. Especially, the relationship between attention deficiency and hypoxia which could cause irreversible cerebrum damage has an implication in cognitive impairment prevention through early treatment.