• Journal of the Korea Society of Computer and Information
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• v.25 no.9
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• pp.91-100
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• 2020

This paper presents an evaluation framework for prototyping multimedia streaming services including audio and video in a distributed and/or decentralized storage that can evaluate service quality and performance under various network conditions. The evaluation framework focuses on important indicators which measure and improve service quality by applying decentralized storage to multimedia streaming services that can mimic the scalability of the existing server-client software architecture and the issue of a single point of failure. The integrated framework not only measures performance indicators for evaluating the quality and performance of multimedia streaming on open source based multimedia content streaming services, but also adjusts network quality using network virtualization technology for comprehensive evaluations. The experimental results show that the integrated framework has low overhead in building and operating a decentralized storage with multimedia streaming services on a single host computer which validates the scalability of the developed framework.

• Journal of Digital Convergence
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• v.13 no.11
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• pp.337-348
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• 2015

Touch input method is unintended difficulties regarding touch and input have increased with touch input methods when compared to using a mouse for input in previously existing menus. This study attempted to analyze usability evaluations according to form and size changes of minimal button forms in button menus. This attempted to verify possibilities through more effective applications of the quantitative performance prediction evaluation model through comparative analysis of Fitts' Law, the representative model of the regression model formula and the interface human performance evaluation method, so that applications can be made in interface designs of touch input methods. Therefore it was significant in that it made reflections on design with consideration given to use user times according to button forms and size changes that can be applied to touch screens.

• Structural Engineering and Mechanics
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• v.56 no.4
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• pp.549-567
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• 2015

A first-order moment method (FORM) reliability analysis is commonly used for structural stability analysis. It requires the values and partial derivatives of the performance to function with respect to the random variables for the design. These calculations can be cumbersome when the performance functions are implicit. A Gaussian process (GP)-based response surface is adopted in this study to approximate the limit state function. By using a trained GP model, a large number of values and partial derivatives of the performance functions can be obtained for conventional reliability analysis with a FORM, thereby reducing the number of stability analysis calculations. This dynamic renewed knowledge source can provide great assistance in improving the predictive capacity of GP during the iterative process, particularly from the view of machine learning. An iterative algorithm is therefore proposed to improve the precision of GP approximation around the design point by constantly adding new design points to the initial training set. Examples are provided to illustrate the GP-based response surface for both structural and non-structural reliability analyses. The results show that the proposed approach is applicable to structural reliability analyses that involve implicit performance functions and structural response evaluations that entail time-consuming finite element analyses.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.2
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• pp.12-22
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• 2002

This study examines the visitors'evaluations of tourism resources in Insa-dong, which the Seoul metropolitan government has improved recently. This study adopted the method of Importance-Performance Analysis by collecting data through questionnaires. A random sampling of visitors to Insa-dong was conducted in June and July,2001. The survey included questions on the physical and psychological components of Insa-dong's tourism resources. In the case of physical components, eight factors(ancient arts shop, art gallery, atelier, calligraphy shop, pottery arts, traditional tea house, antique shop, traditional clothes) out of thirteen were categorized as 'keeping up the good work'. None of the Physical components was shown as 'low priority'or'possible overkill'. In particular, four factors(restaurant, heritage, Korean-style house and alley, traditional cultural festival) need to be impoved most urgently in terms of visitors'satisfaction. Survey results realize them as high priority in importance but low in performance, thereby designated as, 'concentrate here'. An image of the 'street' showed to be high in importance and identical in performance, so can be categorized between'keeping up the good work'and 'concentrate here'. The results show that unusual outdoor spaces and the festivals of Insa-dong have a significant meaning to the visitors. In the case of psychological components, three factors(general atmosphere experience of unusual atmosphere, appropriateness of stroll time) out of seventeen were categorized as 'keeping up the good work'. Ore factor (shopping) was designated as 'low priority'and not found to be 'possible overkill'. Thirteen factors (various events, possibility of various activity, various flood, richness of play, new experience, education cultural inheritance, parking facilities, resting places, green spaces, meeting places, guide map and information, cleanliness of facilities/convenience) need to be improved mast urgently in terms of visitors' fulfillment. They are perceived as areas of 'concentrate here'. This confirms that attractive events are essential for the recent visitor satisfaction. Furthermore, visitors are not satisfied with its amenity and acccss in Insa-dong despite the improvements. In conclusion, positive impressions, both physical and psychological, should be maintained while factors mentioned to be lacking should be prioritized in order of necessity to improve the image of Insa-dong and solutions need to be found and implemented. The results of this study would be helpful in the planning and management of nsa-dong considering the visitors'requirements.

• Journal of KIISE
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• v.45 no.1
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• pp.9-14
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• 2018

Tar is a Linux command that combines several files into a single file. Combining multiple small files into large files increases the compression efficiency and data transfer speed. However, tar has a problem in that smaller target files, result in a lower performance. In this paper, we show that this performance degradation occurs when tar reads the data from the target files and propose qtar (quick tar) to solve this problem via flash-level remapping. When the size of an I/O request is less than 1 MB, the I/O performance decreases proportionally to the decrease in size of the I/O request. Since tar reads the data of files one by one, a smaller file size results in a lower performance. Therefore, the remapping technique is implemented in qtar to read data from the target files at the maximum I/O size regardless of the size of each file. Our evaluations show that the execution time with qtar is reduced by up to 3.4 times compared to that with tar.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.286-295
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• 2011

This case study was to examine the effect of the sensory integration therapy on the Goldenhar syndrome child with tactile defensiveness, developmental delay and occupational performance difficulties. The child was 7.10 year old boy. For intervention, four evaluations were used and the results are as follows. First, in Canadian Occupational Performance Measure showed occupational performance goal as reading and writing in upright position. Second, in Short sensory profile and sensory history, significant differences between sensory sensitivity and tactile processing. Third, in Developmental Profile-3 showed delay. Fourth, in Bruininks-Oseretsky Test of Motor Proficiency-2 showed below average. After intervention, the results of which showed a positive changes. Therefore, this case study is found that the sensory integration therapy is effective in the Goldenhar syndrome child with tactile defensiveness and developmental delay.

• Journal of Korean Academic Society of Home Health Care Nursing
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• v.11 no.1
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• pp.44-56
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• 2004

This study was conducted to investigate the evaluation of students on a practical performance of the home health care and to provide data for practical education on the home care nurse institution. Research was performed from March to December. 2002. 40 Respondents participated in the evaluation four times. The data were analysed by using the SPSS/PC + version 10. 0. The results of this study were as followings: 1. The average age of the subjects was 32. Majority of the subjects were interested in home health care. Majority of the subjects were staff nurse(57.5%) and workers at general hospitals(50%). 2. According to the result of the comparison of practical performances. performance evaluations of 20 items were higher when they admitted special practice than when they admitted any other practice. There was an positive increase in the evaluation of health assessment. nursing documentation. explanation. coping with emergency status. coordination and self assertion. In addition to health assessment. CPR. oxygenation. education & consultation. developmental assessment of child. nursing documentation. mastering nursing practice and consideration of client were significantly different. 3. The subjects were useful for practical circumference where they are working at. From these research findings. the following suggestions have been drawn: it is needed to manage practical curriculum variously and to include not only clinical aspect but also organic or administrational aspect and to reflect on students' needs and to choose to be reasonable items and to develop instruments for evaluation capability of home care nurse.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.39 no.1
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• pp.14-22
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• 2002

We propose the fuzzy BCMP queueing network model for the performance evaluation of distributed processing system with the ambiguous arrival rates of job, service requirements, and service rates of server by the network environments. This model is classified as the open and closed type whether or not the network accepts jobs from the system outside. We derived the measures for system performances such as the job average spending time, average job number in the system and server utilizations using fuzzy mean value analysis which can process the fuzzy factors for both types. Computer simulation was performed for verifying the effectiveness of derived equations of performance evaluation. The fuzzy BCMP queueing network model was evaluated according to the fuzzy arrival rates of job, the number of clients, and the fuzzy service requirements of job for each the open and closed type. The results were agreed with the predicted performance evaluations of the system.

• Korean Journal of Remote Sensing
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• v.38 no.4
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• pp.327-341
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• 2022

Cloud removal is often required to construct time-series sets of optical images for environmental monitoring. In regression-based cloud removal, the selection of an appropriate regression model and the impact analysis of the input images significantly affect the prediction performance. This study evaluates the potential of Gaussian process (GP) regression for cloud removal and also analyzes the effects of cloud-free optical images and spectral bands on prediction performance. Unlike other machine learning-based regression models, GP regression provides uncertainty information and automatically optimizes hyperparameters. An experiment using Sentinel-2 multi-spectral images was conducted for cloud removal in the two agricultural regions. The prediction performance of GP regression was compared with that of random forest (RF) regression. Various combinations of input images and multi-spectral bands were considered for quantitative evaluations. The experimental results showed that using multi-temporal images with multi-spectral bands as inputs achieved the best prediction accuracy. Highly correlated adjacent multi-spectral bands and temporally correlated multi-temporal images resulted in an improved prediction accuracy. The prediction performance of GP regression was significantly improved in predicting the near-infrared band compared to that of RF regression. Estimating the distribution function of input data in GP regression could reflect the variations in the considered spectral band with a broader range. In particular, GP regression was superior to RF regression for reproducing structural patterns at both sites in terms of structural similarity. In addition, uncertainty information provided by GP regression showed a reasonable similarity to prediction errors for some sub-areas, indicating that uncertainty estimates may be used to measure the prediction result quality. These findings suggest that GP regression could be beneficial for cloud removal and optical image reconstruction. In addition, the impact analysis results of the input images provide guidelines for selecting optimal images for regression-based cloud removal.

• Economic Analysis
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• v.17 no.4
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• pp.30-51
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• 2011

Since the previous studies on the effects of trade liberalization implicitly assume that trade liberalization affects economic performance only in any point in time, they inevitably are static. Static evaluations fail to account for cumulative dynamic effects of trade liberalization that affect continuously economic performance. This paper tries to fill this gap of the previous studies in this field, estimating cumulative effects of trade liberalization on economic performance by employing an dynamic version of empirical model. One of important empirical issue is controlling bias from endogeneity. To resolve this problem, this paper employes system GMM that uses lagged first-differences as instruments for level equations and lagged levels as instruments for first-differences equations. It improves upon cross-section estimators because it controls for the potential bias induced by the omission of industry-specific effects and the endogeneity of all regressors. This study investigates the effects of trade liberalization in Korean manufacturing for the period from 1988 to 2005 and finds that cumulative dynamic effects of trade liberalization are present and bigger than static effects.