• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.251-258
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• 2004

This paper proposes a method for estimating the illuminant chromaticity using the distributions of the camera responses obtained by a CCD camera in a real-world scene. Illuminant estimation using a highlight method is based on the geometric relation between a body and its surface reflection. In general, the pixels in a highlight region are affected by an illuminant geometric difference, camera quantization errors, and the non-uniformity of the CCD sensor. As such, this leads to inaccurate results if an illuminant is estimated using the pixels of a CCD camera without any preprocessing. Accordingly, to solve this problem the proposed method analyzes the distribution of the CCD camera responses and selects pixels using the Mahalanobis distance in highlight regions. The use of the Mahalanobis distance based on the camera responses enables the adaptive selection of valid pixels among the pixels distributed in the highlight regions. Lines are then determined based on the selected pixels with r-g chromaticity coordinates using a principal component analysis(PCA). Thereafter, the illuminant chromaticity is estimated based on the intersection points of the lines. Experimental results using the proposed method demonstrated a reduced estimation error compared with the conventional method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.6
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• pp.917-926
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• 1999

In this paper, the recording device for measuring the magnetic field waveforms associated with the cloud lightning discharges was made by the loop-type magnetic field sensor, and the measuring system of a distance between lightning stroke point and observatory site was proposed. The parameters including the time interval of superimposed pulses, zero-to-zero crossing time and the percentage depth of the dip for the positive and the negative magnetic field waveforms were statistically analyzed as a function of the distance between the lightning discharge point and the observatory site. The results could be summarized as follows; Several superimposed pulses were observed at the initial front part of the magnetic field waveform produced by cloud lightning discharges, and the mean time interval between superimposed pulses was about $4\mu\textrm{s}$. Also, the bipolar characteristic appeared significantly and the percentage depth of the dip was about 57~65%. It was known that the zero-to-zero crossing time of the electromagnetic fields is gradually decreased as a distance between lightning discharge point and observatory site is increased.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.77-84
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• 2011

While The passwords that combined with characters and numbers are easy to memorize and use, they have low complexity. Therefore they can easily be revealed by the shoulder-surfing attack when they are inputted through the input devices such like keyboard. To overcome these problems, many new authentication schemes, which change the user secret different form or let users input their secrets through the more complex manners, have been suggested, but it is still hard to find the balanced point between usability and security. S3PAS is one of well-known schemes which had both usability and security against shoulder-surfing attack. However, this scheme was not considered about intersection attack that the attacker tried to pass the authentication system after observing several authentication sessions. In this paper, we consider the security problem of S3PAS; what the attacker can do when he can observe the authentication sessions in several times. We confirm it through user study and experiments. And also we consider the alternative that overcomes the problem.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.2
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• pp.161-166
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• 2024

The current generation of adolescents stands out as the most digitally interconnected in the annals of history, navigating an era characterized by unprecedented levels of technological connectivity. This study explored the impact of smartphone addiction on the quality of peer relationships among adolescents, with a focus on the mediating role of depression. Analyzing data from 2,288 responses of 14-year-old adolescents extracted from the 2022 cross-sectional data of the Korean Children and Youth Panel Survey 2018, research questions were tested. The findings showed that smartphone addiction among adolescents exacerbates depression, consequently leading to a deterioration in the quality of peer relationships. The results contribute to expanding scholarly understanding of the intersection between digital technology and the mental and social well-being of adolescents. Furthermore, there is a call to action for parents, teachers, counselors, policy maker, and practitioner in education institutions to establish programs that monitor and intervene in cases of excessive smartphone use among adolescents.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.7 no.1
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• pp.33-38
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• 2014

Purpose: To determine the therapeutic effectiveness of ultrasound-guided medial branch block (MBB) for the herniated lumbar disc patients who did not relieve their symptoms after percutaneous epidural neuroplasty (PEN). Materials and Methods: From August 2011 to February 2013, 559 patients with herniated lumbar disc have undergone PEN. Among them, ultrasound-guided MBBs were performed for the patients who had sustained low back pain and refered pain to lower extremities. Eighty eight patients were followed at 1 month and 39 patients could be followed at 6 month. All procedures have been performed by the one operator, and 23 G, 10 cm needle was placed and 0.5% lidocaine was injected under ultrasound guide. To target medial branches from L1 to L5, the groove at the root of transverse process and the base of superior articular process has been identified on transverse scan. Patients were evaluated by Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) at each follow-up. Significant pain relief was described as a 50% or more reduction in VAS and significant improvement in function was described as at least a 40% reduction in ODI. Results: VAS showed that preprocedure pain ($7.35{\pm}1.68$; $mean{\pm}SD$) significantly decreased 1 month after block ($3.36{\pm}2.98$) and 6 month ($3.05{\pm}2.27$) (p<0.05). ODI also showed that preprocedure score ($32.82{\pm}8.77$) significantly decreased at 1 month ($15.14{\pm}14.01$) and 6 month ($12.97{\pm}8.82$) (p<0.05). Significant pain relief was observed in 64.49% at 1 month and 64.10% at 6 month. Significant functional improvement in 59.81% at 1 month and 61.54% at 6 month. Conclusion: Ultrasound-guided medial branch block may sufficiently treat the facet problems secondary from disc disease.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.22-24
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• 2005

이동 컴퓨팅 환경에서 통신 네트워크가 갖는 무선 채널 대역폭의 협소함과 이동 단말기의 에너지 제약으로 인해, 다수의 이동 클라이언트들에게 데이터를 전달할 때에는 다수의 클라이언트들의 동시 데이터 접근을 지원하는 브로드캐스트 방법을 사용함으로써 제약점들을 보완할 수 있다. 본 논문에서는 클라이언트의 에너지와 데이터에 대한 접근시간(access time)의 효율을 높이기 위해 데이터의 접근빈도(access frequency)를 고려한 브로드캐스트 방법과 브로드캐스트 인덱스를 추가하는 방법을 함께 반영한 OAF(Data Access Frequencies)브로드캐스팅 기법을 제안한다. DAF브로드캐스팅 기법은 데이터의 접근빈도를 고려한 인덱스를 교차하여 추가함으로써 접근빈도가 높은 데이터를 원하는 다수의 사용자에 대한 접근시간을 줄임으로써 모든 사용자의 평균 접근시간을 줄이는데 목적이 있다. 수학적 분석을 통해 DAF브로드캐스팅 기법을 평가하고 기존의 브로드캐스트 방법과 DAF브로드캐스팅 기법의 성능을 비교 분석한다.

• The Journal of the Korea Contents Association
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• v.22 no.3
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• pp.390-400
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• 2022

University Identity can effectively convey the core values for which schools aim by establishing university identity and integrating one unique image. Therefore, most universities are actively implementing promotional strategies such as newly defining university identity or releasing cultural products. Recently, university brands have been continuously exposed and differentiated through SNS such as Instagram, YouTube, and Facebook as well as existing advertisements and homepages. This study analyzes the identities of the top 80 universities in Korea and China, by referring to the rankings of Asian universities in the 2021 QS World University Rankings, and addresses differences in terms of design shape, number of colors, and use of English. Moreover, 'Cohen's Kappa' consistency analysis was applied to secure data accuracy by analyzing the difference in visual expression of university identity between the two countries through quantification and cross-analysis of visualized university identity design of Korean and Chinese universities. As a result of the study, it is creative, irregular, and has a lot of use of blue, red, and green, and most of them can be seen in less than two colors. In addition, it turns out that word marks and abstract forms of expression are used for university identity design. This study can present implications as effective basic data for internationalizing universities and creating differentiated university identity designs in the future.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.12
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• pp.217-229
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• 2016

The purpose of this study is to determine the nature and recognition of the isolated students and bystanders in respect of friendship in Middle School Physical Education. To achieve these objectives, we analyzed statistical material through PQR and inductive category by completing open questionnaires for 360 students bullied in public middle school in a large city. According the results, first, damages defender of participants showed the highest percentage, 70.2%. There were bystanders(12.3), the alienated(7.4) inflictor(5.5), contributor(4.6) in descending order. Second, according to the results of inductive analysis regarding the nature and recognition of bystanders in physical education, the biggest reason for not helping their colleagues in need is as following: ① improper friendship(32.8), ② lack of moral and emotional empathy(28.1), ③ lack of exercise ability(15.6), ④ psychological burden(12.5), ⑤ improper class attitude(10.9). In numerical order, improper friendship can be the biggest problem that.

• 한국노년학
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• v.39 no.2
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• pp.231-240
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• 2019

The study aimed to identify risk factors for falls as well as hospitalization status according to disease and demographic characteristics of demented inpatients by investigating the in-depth Injury Patient Surveillance System data collected by Korea Centers for Disease Control and Prevention(KCDC). Older adults over 60 years old who were diagnosed with dementia were included(n=1,732). Their data were analyzed after being assigned to either a fall group or a non-fall group. STATA was used for statistical analyses, such as frequency analysis, chi-square (χ²) test, and logistics regression. It was found that 8.0% of the demented inpatients experienced falls. According to the analysis on category of fall and non-fall group were statistically significant difference in age and Charlson Comorbidity Index(CCI) and bone density deficiency. Based on the logistic regression analysis of factors affecting falls, older adults over 80 are 2.386 times more likely to fall and based on a target with a CCI of 0, the risk of falls is 0.421 times lower, finally based on those without bone density disorder, the fall risk for those with bone density disorder was 3.581 times higher. Therefore, we expect that the important about the factors relating to falls identified in this can not only be found valuable for educating inpatients with dementia and care-givers, but also be used as reference that supports clinical professionals to make decisions on falls management for patients with dementia.

• Culinary science and hospitality research
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• v.19 no.2
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• pp.52-64
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• 2013

The purposes of the study were (1) to identify the market segments of home meal replacement(HMR) consumers based on purchasing selection attributes and (2) to investigate demographic characteristics and purchasing behaviors unique to each segmented market. A total of 266 responses were used for data analysis using SPSS 19.0. Data analyses included frequency analysis, chi-square analysis, factor analysis, cluster analysis, MANOVA, and discriminant analysis. The result of the factor analysis showed four important dimensions in selection attributes: food quality, design, convenience, and accessibility. The results of the cluster analysis identified two HMR market segments, namely, highly involved HMR consumers and lowly involved HMR consumers. Highly involved HMR consumers considered all the selection dimensions more important than lowly involved HMR consumers. In addition, these two groups showed different demographic characteristics and purchasing behaviors. Managerial implications were provided.