• The Journal of the Acoustical Society of Korea
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• v.18 no.6
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• pp.77-83
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• 1999

H.263 is an international standard of ITU-T that can makes the service such as video phone, video conference in the transmission line less than 64Kbps. This recommendation draft has used motion estimation/compensation, transform coding and quantizing methods. TMN5 used for the performance estimation of H.263 has fundamentally used DCT in transform coding method and presented quantizer for quantizing the DCT transform coefficient. This paper is presenting adaptive quantizer effectively able to quantize DCT coefficient considering the human visual sensitivity while the structure of TMN5 is maintaining. As quantizer that proposed DCT-based H.263 could make transmit more frame than TMN5 in a same transfer speed, it could lower the frame drop effect. And the luminance signal appeared the difference of -0.3 ～ +0.7dB in the average PSNR for the estimation of objective image quality and the chrominance signal appeared the improvement in about 1.5dB in comparision with TMN5. As a result it can attain the better image quality compared to TMN5 in the estimation of subjective image quality.

• Korean Journal of Psychosomatic Medicine
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• v.25 no.2
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• pp.136-144
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• 2017

Objectives : Cognitive complaints are reported frequently after breast cancer treatments. The causes of cognitive decline are multifactorial, a result of the effect of cancer itself, chemotherapy, and psychological factors such as depression and anxiety. However, cognitive decline does not always correlate with neuropsychological test performance. The purpose of this study was to examine the relationship of subjective cognitive decline with objective measurement and to explore associated factors of cognitive function in breast cancer survivors. Methods : We included 29 breast cancer survivors who complain cognitive decline at least 6 months after treatment and 20 age-matched healthy controls. Neuropsychological tests were performed in all participants. Multivariable regression analysis evaluated associations between neuropsychological test scores and psychological distress including depression and anxiety, also considering age, education, and comorbidity. Results : There were no statistically significant differences in neuropsychological test performances. However, the breast cancer survivors showed a significantly higher depression(p=0.002) and anxiety(p<0.001) than the healthy controls did. Among the cancer survivors, poorer executive function was strongly associated with higher depression(${\beta}=-0.336$, p=0.001) and anxiety(${\beta}=-0.273$, p=0.009), after controlling for age, education, and comorbidity. In addition, poorer attention was also significantly related with depression(${\beta}=-0.375$, p=0.023) and anxiety (${\beta}=-0.404$, p=0.013). Conclusions : The results of this study showed the discrepancies between subjective complaints and objective measures of cognitive function in breast cancer survivors. It suggests that subjective cognitive decline could be indicators of psychological distress such as depression and anxiety.

• Journal of the Korean Arthroscopy Society
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• v.8 no.2
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• pp.89-93
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• 2004

Purpose: To evaluate the clinical stability and function after arthroscopic anterior cruciate ligament(ACL) reconstruction using fresh-frozen tibialis tendon allograft. Materials and Methods: Of the patients who underwent ACL reconstruction using tibialis tendon allograft from July 2002 to June 2003, thirty-one patients could be evaluated and the mean follow-up period was 19 months. Evaluations included were Lysholm knee score, 2000 International knee Documentation Committee (IKDC) subjective knee score, Lachman test, pivot shift test, KT-1000 arthrometer measurement and 2000 IKDC knee examination. Results: The mean Lysholm score was 88. Twenty-eight patients (90.3%) were good or exellent for the measured parameters. Twenty-seven patients(87.1%) was over 70 in IKDC subjective knee score. Thirty patients (96.8%) had 1+ firm end or negative Lachman test. 27 patients (87.1%) had a negative pivot shift. Thirty patients (96.8%) had less than 5mm difference of maximal manual difference by KT-1000 arthrometer. Twenty -nine patients (93.5%) were nearly normal or normal grade by 2000 IKDC knee examination. Complications were 1 case of failure and 1 case of infection. Conclusion: ACL reconstruction with the double-stranded fresh-frozen tibialis tendon allograft resulted in a reliable and predictable outcome after short-term follow-up.

• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.457-466
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• 2021

This study sought to identify the effectiveness of training programs by developing mobile app-based training programs to enhance memory, attention, and language function, which is known to be vulnerable to menopause women. It was conducted on 40 Climacteric woman between 40 to 60 years complaining about cognitive function decline. The mobile app-based cognitive training was an 8 week program. There were a total of 24 sessions and each session took 20-30 minutes, three times per week. The survey was carried out including a baseline study pre and post intervention study. The research variables were objective cognitive function (overall cognitive function, memory, attention, and language function), subjective cognitive function and quality of life. The cognitive training program showed a significant increase in overall cognitive function(t=-8.688, p<.001), memory(t=-4.765, p<.001), attention : number of correct answers(t=-7.293, p<.001), language high frequency response speed(Z=-2.179, p=.036), language low frequency response speed(Z=-2.737, p=.009) and quality of life (t=-3.358, p=.002). However, there was no significant difference in the scores for subjective cognitive function. The cognitive training program was found to be an effective intervention for improving the cognitive function of Climacteric women. It could be used as a cognitive intervention tool that is accessible at home without expert help.

• Environmental and Resource Economics Review
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• v.28 no.4
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• pp.645-673
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• 2019

The hypothetical nature of stated preferences can lead to a hypothetical bias that might work as a normative pressure, influencing survey responses. This paper aims to test the impact of social desirability bias by comparing economic estimates based on both subjective and objective valuation questions. The case study is about an urban riverine restoration project in Deajeon, South Korea. As valuation methods both contingent valuation and choice experiments were comparatively applied. Based on a nationally representative sample of 1,000 respondents, the test results offered contrasting conclusions between two test approaches. Accroding to the estimation results based on the conventional valuation, the marginal willingness to pay estimates are 10,500 KRW from CV; and 18,600 KRW for improving water quality, 2,200 KRW for the inside view, 8,900 KRW for the outside view, and 5,800 KRW for biodiversity from CE. A segmentation-based approach is a conventionally used method, which showed a limited impact of social desirability on willingness to pay estimates. The alternative parameterization-based approach measures a model-wide impact of social desirability, proving a significant bias. Although the study positioned a cheap-talk statement before the valuation section of the survey questionnaires, which might have pre-screened the bias, the overall implications of the results suggest a caution in reducing and observing hypothetical bias. There might remain a significant and substantial hypothetical bias even after cheap-talk, particularly in situations with strong social desirability, so that the potential role of objective valuation questions is guaranteed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4432-4439
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• 2012

Previous studies on art pricing mostly focused on auction data because of the limitation of non-auction market data. This study investigated on both auction and non-auction markets to see the difference in art pricing mechanisms of both markets. Especially, while prior hedonic models included only quantatative variables to predict art prices, we added a qualitative measure, artistic value of a artwork, along with the original hedonic model to develop a more comprehensive model, and tested if his change may make more precise predictions. As a result, when we did not divide our data into auction and non-auction groups, we did not find any significant difference between the original hedonic model and the new model including artistic value. However, when we separated non-auction group from auction group, we found that predicted prices in the new model showed significantly closer values to the actual prices. This study contributes to our knowledge on art pricing by showing that artistic value may have important but differential impacts on different art dealing channels.

• Journal of the Korean Wood Science and Technology
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• v.47 no.2
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• pp.229-238
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• 2019

Various wood defects occur during tree growing or wood processing. Thus, to use wood practically, it is necessary to objectively assess their quality based on the usage requirement by accurately classifying their defects. However, manual visual grading and species classification may result in differences due to subjective decisions; therefore, computer-vision-based image analysis is required for the objective evaluation of wood quality and the speeding up of wood production. In this study, the SIFT+k-NN and CNN models were used to implement a model that automatically classifies knots and analyze its accuracy. Toward this end, a total of 1,172 knot images in various shapes from five domestic conifers were used for learning and validation. For the SIFT+k-NN model, SIFT technology was used to extract properties from the knot images and k-NN was used for the classification, resulting in the classification with an accuracy of up to 60.53% when k-index was 17. The CNN model comprised 8 convolution layers and 3 hidden layers, and its maximum accuracy was 88.09% after 1205 epoch, which was higher than that of the SIFT+k-NN model. Moreover, if there is a large difference in the number of images by knot types, the SIFT+k-NN tended to show a learning biased toward the knot type with a higher number of images, whereas the CNN model did not show a drastic bias regardless of the difference in the number of images. Therefore, the CNN model showed better performance in knot classification. It is determined that the wood knot classification by the CNN model will show a sufficient accuracy in its practical applicability.

• Journal of the Korean Arthroscopy Society
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• v.9 no.2
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• pp.206-213
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• 2005

Purpose: To evaluate the outcome of symptomatic osteochondritis dissecans of the talus treated with arthroscopic debridement and multiple drilling. Materials and Methods: Between 1997 and 2003, 14 arthroscopic debridement(group I) and 15 arthroscopic multiple drilling(group II) were performed. There are 21 male and 8 female patients. Mean age was 34.4 years(33.8 years in group I, 37.5 years in group II) and average follow-up period was 43.2 months(46.4 months in group I, 40.1 months in group II). Simple radiographs and MRI were performed preoperatively and postoperatively, and the progressive stage of the lesions was evaluated through the arthroscopic surgery. Clinical results were evaluated with ankle-hindfoot scale and scoring scale for subjective and objective functional outcomes. The results were compared between 2 groups. Results: There are 20 medial(7 in group I, 13 in group II), 6 lateral(5 in group I, 1 in group II), and 3 both-side(2 in group I, 1 in group II) lesions. According to the classification of Berndt and Harty, there are 4 stage II(4 in group I, 0 in group II), 19 stage III(9 in group I, 10 in group II), and 6 stage IV(1 in group I, 5 in group II). According to the ankle-hindfoot score, the mean score was significantly improved $53.1{\pm}2.7$ points preoperatively to $85.1{\pm}8.5$ points postoperatively in group I and $54.6{\pm}6.8\;to\;80.7{\pm}8.5$ points group II. Subjective and functional scores was also improved $49.6{\pm}10.5$ points preoperatively to $84.6{\pm}7.7$ points postoperatively in group I and $50.7{\pm}9.2\;to\;83.0{\pm}9.6$ points in group II. But there were no statistical significance between them. Conclusion: Arthroscopic debridement and multiple drilling for the treatment of osteochondral lesions of the talus showed successful results and there was no statistically significant difference between them.

• Journal of the Korean Society of Safety
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• v.22 no.6
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• pp.91-97
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• 2007

A survey of risk perception in Korea was conducted in 2001 with a special emphasis on industrial and technological risks. This article summarizes the characteristics of risk perception in consideration of socio-demographic background of respondents. The survey with sample size of 1,870 evaluates the perceived level of 25 risk items in the areas of transportation, chemicals, environment, industry, and nuclear power generation. Risks are categorized by using factor analysis to clarify attitudinal or behavioral properties of risk perception. Research findings show that the level of perceived risk does not correspond to the statistical level. Socio-demographic variables are significant predictors in explaining risk perception, or the discrepancies between "subjective" and "objective" risks. Effective risk communication can reduce the perceptional discrepancies, improve the awareness of technological risks, and ultimately facilitate the process of making and implementing policies for risk management and safety regulation. This article tries to provides policy guidelines for "Who is the target for risk communication" and "Which risk has the policy priority for safety improvement." Married females at the age of 30s and 40s with lower education and lower income in small cities are more vulnerable to risk misperception than other groups. More information and knowledge regarding unfamiliar, intangible, new technological risks should be delivered to the vulnerable groups for reducing perceptional bias. Society-wide safety can be improved by integrating policy, human, and social factors as well as techno-engineering advances.

• Archives of design research
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• v.15 no.4
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• pp.253-262
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• 2002

Without the involvement of time in animation, it cannot be possible to create movement. Therefore, tine is the important element to create animation. In animation, the expression of the emotion of character is more complicate than the appearance. Time is one of element to use for express of the emotion. It can be divided two types of time as the real time and the animation time broadly. The real time has linear, irreversible and analogue form which is in our daily life. And the animation time has multi-direction, reversible, and digital form which can be detected in the movie. For the animation time, there are many types of time that are the running time, the production time, the subjective time, the objective time, the ambiguous time and the universal time etc. This study is to extend and enrich the express as film language through various types of times in animation. Time is one of important element that can be useful method for expressing many unique scenes in film art as film language.