• Korean Journal of Construction Engineering and Management
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• v.12 no.5
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• pp.71-80
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• 2011

Flying net should be installed on every 3 or 4 construction floor from 8m above ground according to the rule. In the apartment housing construction, flying net installation work has been recognized the most dangerous work among the whole works because a small mistake of labors might make their death accident. Sub-contractors specialized in flying net have been developing various flying net types. However, most works of installing flying net as working with the developed system are performed outside the apartment housing, so that the risk of fall in works of installing supports and unfolding net is still high. Furthermore, as using the previously developed flying net labors might bump into the frame or the wire rope for supporting so that it makes secondary accidents. The objective of this research is to produce the proto-type of anti-collision flying net system based on the result of problem analysis on the installation and detachment process and suggest the improved anti-collision flying net system, which is able to improve safety and field applicability by conducting field experiment and analyzing performance.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.6
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• pp.209-220
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• 2014

Compressive Sensing (CS) is a new signal acquisition paradigm which enables sampling under Nyquist rate for a special kind of signal called sparse signal. There are plenty of CS recovery methods but their performance are still challenging, especially at a low sub-rate. For CS recovery of natural images, regularizations exploiting some prior information can be used in order to enhance CS performance. In this context, this paper addresses improving quality of reconstructed natural images based on Dantzig selector and smooth filters (i.e., Gaussian filter and nonlocal means filter) to generate a new regularization called smooth residual error regularization. Moreover, total variation has been proved for its success in preserving edge objects and boundary of reconstructed images. Therefore, effectiveness of the proposed regularization is verified by experimenting it using augmented Lagrangian total variation minimization. This framework is considered as a new CS recovery seeking smoothness in residual images. Experimental results demonstrate significant improvement of the proposed framework over some other CS recoveries both in subjective and objective qualities. In the best case, our algorithm gains up to 9.14 dB compared with the CS recovery using Bayesian framework.

• The Journal of Korean Academy of Sensory Integration
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• v.7 no.2
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• pp.49-61
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• 2009

Objective : This study is designed to investigate the children' preference in play and leisure activities in accordance with age, gender, demographic, school interest and scholastic performance. Method : A total of 204 children and youths aged in 8-17 years living in urban and rural area were recruited. The preference of activities was asked by using the questionnaire and the PAC Korean version. Results : There are differences in activity preferences according to age, gender, school interest. Girls showed higher preference in most PAC scales except for physical activities than boys. As the younger children are, the greater preference in recreation activities is shown. There were no significant differences of activity preference in demographic variable and scholar performance. The higher interest of school the children had, the greater preference in formal and social activities was shown. Conclusions : This study showed that there is play and leisure activity preference in children and youths according to age, gender, and school interest. The result of this study would be helpful for occupational therapists working with school-aged children and youths.

• Particle and aerosol research
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• v.12 no.3
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• pp.95-102
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• 2016

Controlling exposures to occupational hazards is important for protecting workers. Certified facepiece respirators are recommended when engineering controls do not adequately prevent exposures to airborne nanomaterials. The objective of this study is to carry out the experimental performance test to investigate the fractional efficiencies of the filter media for two grades of facepiece respirators. Experimental performance evaluations were carried out for the test NaCl particles and silver nanoparticles. For media of respirator filter, the penetration of NaCl particles was less than 5% and the most penetrating particle size occurred at about 40 nm. For silver nanoparticles, the most penetrating particle size was about 20nm with higher efficiency than those of NaCl particles. Charge characteristics of airborne nanoparticles is important because the media of respirator filter is made by the electret filter media.

• Journal of Broadcast Engineering
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• v.20 no.6
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• pp.818-826
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• 2015

Recently, objective image quality assessment (IQA) methods that elaborately reflect the visual quality perception characteristics of human visual system (HVS) have actively been studied. Among those characteristics of HVS, luminance adaptation (LA) effect, indicating that HVS has different sensitivities depending on background luminance values to distortions, has widely been reflected into many existing IQA methods via Weber's law model. In this paper, we firstly reveal that the LA effect based on Weber's law model has inaccurately been reflected into the conventional IQA methods. To solve this problem, we firstly derive a new LA effect-based Local weight Function (LALF) that can elaborately reflect LA effect into IQA methods. We validate the effectiveness of our proposed LALF by applying LALF into SSIM (Structural SIMilarity) and PSNR methods. Experimental results show that the SSIM based on LALF yields remarkable performance improvement of 5% points compared to the original SSIM in terms of Spear rank order correlation coefficient between estimated visual quality values and measured subjective visual quality scores. Moreover, the PSNR (Peak to Signal Noise Ratio) based on LALF yields performance improvement of 2.5% points compared to the original PSNR.

• 한국벤처창업학회:학술대회논문집
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• 2007.11a
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• pp.111-140
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• 2007

This paper was analyzed to improve internal corporate venture system in public companies. The problems of internal corporate venture systems in a public company were as follows: First, lack of the CEO's willingness in venture business was shown. The culture of venture business also was not mature; Second, the employees were behind the effort to develop their business ability; Third, the objective views are needed to screening venture items and evaluation; Fourth, to measure performance of internal corporate venture, a clear basis and measure system were needed. Fifth, the reward was restricted; Finally, the mother-company did not invest any money for the spin-outed ventures The results of the paper were as follows: First, the CEO's support and effusion of venture culture were needed for successful internal corporate venture system; Second, a public company has to provide education program for venture and information--sharing system; Third, outside consultant may be utilized in finding venture items and feasibility evaluation. Fourth, each venture team may be provided a clear object and specific evaluation system based on characteristic of each team; Fifth, performance-base reward system is needed to enhance motivation; Finally, the public company has to provide find for the spin-off venture by utilizing government system and forming venture capital funds.

• Journal of Oriental Neuropsychiatry
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• v.23 no.1
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• pp.93-114
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• 2012

Objective : This study aimed to review the performance of traditional herbal prescriptions for treating dementia and present a strategy for research on dementia therapy utilizing herbal medicine. Methods : A definition was made to clarify the technology regarding the development of herbal prescriptions for treating dementia. The queries were compounded based on the initial keywords provided by experts in the field, then applied to the Web of Science database search engines from January 1986 to September 2011 to search related scientific articles. Before performing the analysis, papers were extracted from the initial search reviewed by experts and 80 articles were selected. Then, the selected papers were analyzed in terms of publish year, country, and type of herbal prescriptions. Furthermore, the research performance evaluation for treating dementia by herbal prescriptions was also created in terms of country and organization based on forward citation analysis. In addition to, for the evaluation regarding research quality, we classified and reviewed papers into two types: clinical studies and experimental studies. Results : According to the quantitative information analysis of 80 articles, the number of papers has increased by 21.9% per the yearly mean from 1995, and Japan had the largest portion within this research field. There were 34 kinds of traditional herbal prescriptions, among them Ukgansan had the highest number of studies followed by Jodeungsan, Dangkisoosan and so on. In addition, quality index as calculated by cites per paper is higher than average in Switzerland, Turkey and Japan. In the view of the evaluation on quality there were 12 clinical studies, 8 RCT reported that herbal prescriptions had efficacy at cognition, behavioral & psychological symptoms (BPSD) and activity of daily life (ADL) in various type of dementia. In experimental studies most of the studies were performed using animal models. The studies using Ukgansan were aimed at improving BPSD. The papers studied with Jodeungsan and Dangkisoosan targeted vascular dementia. Conclusions : In this study, research to develop traditional herbal prescriptions for treating dementia has the potential to improve symptoms since herbal medicines work as both multi-function and multi-target in dementia with multiple pathological or neurotoxic pathways. Therefore, the results of the research should be used in order to establish strategies to develop technology for treating dementia with traditional herbal prescriptions in the future.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.6
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• pp.642-653
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• 2008

This study deals with modeling of head-related transfer functions(HRTFs) using principal components analysis(PCA) in the time and frequency domains. Four PCA models based on head-related impulse responses(HRIRs), complex-valued HRTFs, augmented HRTFs, and log-magnitudes of HRTFs are investigated. The objective of this study is to compare modeling performances of the PCA models in the least-squares sense and to show the theoretical relationship between the PCA models. In terms of the number of principal components needed for modeling, the PCA model based on HRIR or augmented HRTFs showed more efficient modeling performance than the PCA model based on complex-valued HRTFs. The PCA model based on HRIRs in the time domain and that based on augmented HRTFs in the frequency domain are shown to be theoretically equivalent. Modeling performance of the PCA model based on log-magnitudes of HRTFs cannot be compared with that of other PCA models because the PCA model deals with log-scaled magnitude components only, whereas the other PCA models consider both magnitude and phase components in linear scale.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.4
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• pp.35-55
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• 2008

The primary objective of his study is to investigate the factors influencing the implementation performance of K public corporation's ERP system from end user perspective. For this purpose, a research model and hypotheses are developed based on the literature reviews of IS Success Models. Data has been collected from 276 users who have used ERP system in K public corporation and the research hypotheses were tested using covariance structure model analysis. The hypotheses test results of this study are summarized as follows. Firstly, system quality has a positive influence on system usage, but information quality and service quality do not have significant influence on system usage. Secondly, all of three quality factors which are information quality, system quality, and service quality, have positive influence on user satisfaction. Lastly, both of system usage and user satisfaction have positive influence on user performance. From the analyses, this research ends with implications, as well as limitations and future research directions.

• Journal of Environmental Health Sciences
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• v.41 no.3
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• pp.203-215
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• 2015

Objectives: This study was designed to evaluate the filtration efficiencies and pressure drops of five commercial cloth masks (4 plate type, 1 cup type) in comparison to the performance of a class 1 disposable respirator (reference respirator). A further objective was to evaluate the effects of the number of layers and wash treatment independently on filtration efficiencies and pressure drops. Methods: Polydisperse NaCl aerosols were generated in an aerosol chamber and their concentrations were measured by an optical particle counter (OPC) in the size range of $0.3{\sim}10{\mu}m$ (five channels). Results: The filtration efficiencies of the five cloth masks and the reference respirator were D: 9.5%, C: 18.5%, E: 23.6%, A: 28.5%, B: 29.7% and R: 91.1%, respectively, and the pressure drops through them were C, D: 0.8 Pa, E: 1.7 Pa, B: 6.4 Pa, A: 42.7 Pa and R: 19.3 Pa, respectively. The filtration efficiencies of the cloth masks and reference respirator were below the class 1 respirator criterion (${\geq}94.0%$) of the Ministry of Employment and Labor (MOEL) and Ministry of Food and Drug Safety (MFDS). The pressure drops satisfied the class 1 respirator criterion (${\leq}70Pa$) of MOEL and MFDS. When the cloth masks were folded into two and four layers, the filtration efficiencies of cloth masks A, B, C, D (plate type) increased 1.7-4.6 times, and 2.3-6.8 times, respectively, compared to the efficiencies of the same products in a single layer. Pressure drops increased as the number of layers was increased. The filtration efficiency of cloth mask E with a liner was 1.3 times higher than that of the same mask without a liner, and the pressure drop was lower in the no-liner configuration. After a single washing, the filtration efficiencies of all the cloth mask products decreased 1.04-4.0 times compared to those of the same products intact. For the cloth masks C and E, their filtration efficiencies were significantly decreased after washing (p<0.05). The pressure drops of all cloth masks were 1.2-2.0 times lower after washing. Conclusions: The filtration efficiencies of the five cloth masks were below 30% and did not improve greatly by increasing the number of layers. After a single washing, their performances decreased. Considering the above and other issues identified with cloth masks, such as poor fit and stretched fibers through use, people should not expect protection against particulate matters from the cloth masks on the market.