• Title/Summary/Keyword: Performance Evaluations

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Fractional efficiency of Nanomaterials for the High efficiency respiratory filters (고효율 호흡보호구의 나노물질 입경별 제거 효율)

  • Lee, Gwang-Jae;Ji, Jun-Ho;Kim, Won-Geun;Yook, Se-Jin;Kim, Jong-Kyo;Kim, Jung-Ho
    • 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.

Design and Implementation of National Language Ability Test System using Korean Style Internet-Based Test added Middle-Server (미들서버방식 한국형 IBT를 이용한 국가언어능력평가 시스템의 설계 및 구현)

  • Chang, Young-Hyun;Park, Dea-Woo
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.9
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    • pp.185-192
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    • 2011
  • The purpose of this paper is to propose the design and implementation of a korean style internet-based test system on the basis of efficiency and stability for middle server. The current assessment system has some unstable elements with regard to transmission procedure, cost, system load and stability. This paper proposes a series of activities for the performance improvement of korean style internet-based test system which finally produced various excellent results in the administration of expense control, human resources, and special operational affairs. The proposed system's technological factors using middle server have been tested through a basic simulation pilot system. Actual development procedure starts from the analysis required by improving the shortcomings of existing internet-based test systems. A efficiency comparison with existing system and newly developed system was made in the area of number of operators, abnormal processing, system maintenances. Korean style internet-based test system using middle server has shown great efficiency increased to the maximum of 2 times about the effectiveness of processing for various parts. The korean style internet-based test system using middle server have been given good evaluations with regard to the convenience of their use and the management system for operators and supervisors.

Effects of four dim vs high intensity red color light regimens on growth performance and welfare of broilers

  • Senaratna, D.;Samarakone, T.S.;Gunawardena, W.W.D.A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.31 no.1
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    • pp.149-156
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    • 2018
  • Objective: Broilers show clear preference towards red color light (RL). However setting of an optimum light intensity is difficult since dim intensities that favor growth reduce welfare. This experiment was conducted to test the most effective RL intensity regimen (Dim [5 lux; DI] vs high [320 lux; HI]) in combination applied at different growth stages that favors for both performance and welfare. Methods: Complete randomize design was adopted with 6 replicates. Treatments were; T1 = early DI (8-21 d)+latter HI (22-35 d); T2 = early DI (8-28 d)+latter HI (29-35 d), T3 = early HI (8-21 d)+latter DI (22-35 d), T4 = early HI (8-28 d)+latter DI (29-35 d) and T5 = control (white light; WT) (8-35 d) at medium intensity (20 lux). Body weight (BW), weight gain (WG), water/feed intake and ratio, feed conversion ratios (FCR) were assessed. Common behaviours (15) were recorded by scan sampling method. Lameness, foot pad dermatitis, breast blisters, hock burning damage were assessed as welfare parameters. Fear reactions were tested using Tonic Immobility Test. Ocular and carcass evaluations were done. Meat and tibiae were analyzed for fat and bone ash respectively. Results: On 35 d, the highest BW ($2,155.72{\pm}176g$), WG ($1,967.78{\pm}174g$) were recorded by T2 compared to WT ($BW_{WT}=1,878.22{\pm}155$, $WG_{WT}=1,691.83{\pm}160$). But, application of RL, either DI, or HI during early/latter stage had no significant effect on FCR. Under HI, birds showed much higher active behaviours. DI encourages eating. Though LI changed from DI to HI, same trend could be seen even under HI. The highest leg strength ($218.5{\pm}120s$) was recorded by T2. The lowest leg strength ($64.58{\pm}33s$) and the highest ocular weight ($2.48{\pm}1g$) were recorded by T1. Significantly (p<0.05) the highest skin weight ($162.17{\pm}6g$) but the lowest fat% in meat ($13.03%{\pm}5%$) was recorded by T2. Conclusion: Early exposure to DI-RL up to 28 days followed by exposure to HI-RL is the most favorable lighting regimen for optimizing production, better welfare of broilers and improving health benefits of meat.

Mechanical Stability Analysis to Determine the Optimum Aspect Ratio of Rock Caverns for Thermal Energy Storage (열에너지 저장용 암반 공동의 최적 종횡비 결정을 위한 역학적 안정성 해석)

  • Park, Dohyun;Ryu, Dongwoo;Choi, Byung-Hee;Sunwoo, Choon;Han, Kong-Chang
    • Tunnel and Underground Space
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    • v.23 no.2
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    • pp.150-159
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    • 2013
  • It is generally well known that the stratification of thermal energy in heat stores can be improved by increasing the aspect ratio (the height-to-width ratio) of the stores. Accordingly, it will be desirable to apply a high aspect ratio so as to demonstrate the good thermal performance of heat stores. However, as the aspect ratio of a store increases, the height of the store become larger compared to its width, which may be unfavorable for the structural stability of the store. Therefore, to determine an optimum aspect ratio of heat stores, a quantitative mechanical stability assessment should be performed in addition to thermal performance evaluations. In the present study, we numerically investigated the mechanical stability of silo-shaped rock caverns for underground thermal energy storage at different aspect ratios. The applied aspect ratios ranged from 1 to 6 and the mechanical stability was examined based on factor of safety using a shear strength reduction method. The results from the present study showed that the factor of safety of rock caverns tended to decrease with the increase in aspect ratio and the stress ratio of the surrounding rock mass was influential to the stability of the caverns. In addition, the numerical results demonstrated that under the same conditions of rock mass properties and aspect ratio, mechanical stability could be improved by the reduction in cavern size (storage volume), which indicates that one can design high-aspect-ratio rock caverns by dividing a single large cavern into multiple small caverns.

An Analysis of Medical Articles Published Domestically and Abroad by Korean Researchers from 1960 to 2008 (국내의학자가 국내외에 발표한 의학논문 현황 분석 - 1960년부터 2008년까지 -)

  • Jang, Hae-Lan;Kang, Gil-Won;Lee, Young-Sung;Tak, Yang-Ju
    • Journal of the Korean Society for Library and Information Science
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    • v.45 no.3
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    • pp.259-277
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    • 2011
  • The purpose of this study is to analyze how the changes of evaluation standards have affected Korean medical researchers' academic performance by comparing the publication status of medical articles both domestically and abroad. A total of 314,559 domestic articles in KMbase and 53,423 articles stored in MEDLINE published abroad by Korean researchers were analyzed. All of the data were compared per year according to the research field and indexed journals by numbers and proportions of articles published domestically and abroad. The analysis showed that the number of total articles and the proportion of articles published abroad increased continuously. In the early 2000s, articles published in Korea decreased, otherwise articles published abroad increased sharply. SCI articles showed a steady increase before 2000, and continued to increase over the next few years. KCI articles also showed a rapid increase in the early 2000s while other articles were decreasing. Publication trends shown in this study were similar despite quantitative and timely differences by research area. Performance evaluations focusing on SCI articles affected on quantitative decrease in the number of total articles published domestically. Quantitative growth itself is not an absolute indicator for academic achievement. Therefore, to complement any evaluation of academic achievement, qualitative analysis needs to be done as well.

Design and Implementation of Wireless Power Transfer System for a Personal Rapid Transit (PRT) Vehicle (PRT 차량의 무선급전 시스템 설계 및 구현)

  • Kang, Seok-Won;Jeong, Rag-Gyo;Byun, Yeun-Sub;Um, Ju-Hwan;Kim, Baek-Hyun
    • Journal of Digital Convergence
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    • v.12 no.11
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    • pp.289-298
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    • 2014
  • Recently, the traditional paradigm in railroad technology is changing as more efficient and cost-effective electric vehicle (EV) technologies have emerged. The original concept of PRT (Personal Rapid Transit) proposed in the past has come to be regarded as unrealistic, but its feasibility is improving through the utilization of an EV platform. In particular, battery-powered vehicles pose difficult technical challenges in attempts to achieve reliable and efficient operation. However, based on the inductive power transfer (IPT) technology, the fast charging of supercapacitors with high energy density can contribute to overcoming this technical challenge and promote the transition to electric-powered ground transportation by improving the appearance of cities. This study discusses the development process of a power supply system for PRT, including concept design, numerical analysis, and device manufacturing, along with performance predictions and evaluations. In terms of results, the system was found to meet the performance requirements for power supply modules on a test-bed.

Occupational Therapy for the Improvement of Activities of Daily Living in Children and Adolescents in Korea: Systematic Review (국내 장애아동·청소년의 일상생활활동 향상을 위한 작업치료 : 체계적 고찰)

  • Hong, Eunkyoung
    • The Journal of Korean Academy of Sensory Integration
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    • v.17 no.3
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    • pp.46-60
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    • 2019
  • Objective : The purpose of this study is to provide evidence for a systematic analysis of occupational therapy evaluations and interventions for the activities of daily living of children and adolescents. Methods : The research period was from 2010 to September 2019. The articles were collected from the Research Information Sharing Service (RISS) and Koreanstudies Information Service System (KISS) databases. The key words were 'pediatric occupational therapy & activities of daily living', 'pediatric occupational therapy & self care', 'pediatric occupational therapy & self management', 'pediatric occupational therapy & occupation', 'occupational therapy & eating', 'occupational therapy & AMPS (Assessment of Motor and Process Skills)', 'occupational therapy & WeeFIM (Functional Independence Measure for children'. Results : A total of 14 studies were analyzed, the qualitative level IV, V of the study was 72% of the total research. The diagnosis of participants included 50% intellectual disorder and 20% brain lesion, including cerebral palsy. The most frequently used method to assess the activities of daily living was Canadian Occupational Performance Measure (COPM). The most frequently used method to therapy was sensory integration therapy. The intervention effect of all studies was positive, however, the use of group programs on the occupational therapy on children with intellectually disorder didn't work. Conclusion : In Korea, there are no articles that systematically analyze whether occupational therapy improves the activities of daily living in children and adolescents.

On the asymptotic correlationship for some process capability indices Ĉp, Ĉpk and Ĉpm under bivariate normal distribution (이변량 정규분포 하에서 공정능력지수에 대한 점근적 상관관계에 관한 연구)

  • Cho, Joong-Jae;Park, Hyo-Il
    • The Korean Journal of Applied Statistics
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    • v.29 no.2
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    • pp.301-308
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    • 2016
  • The process capability index is used to determine whether a production process is capable of producing items within a specified tolerance. Some process capability indices $C_p$, $C_{pk}$ and $C_{pm}$ have been of particular interest as useful management tools for tracking process performance. Most evaluations on process capability indices focus on statistical estimation and test of hypothesis. It is necessary to investigate their asymptotic correlationship among basic estimators ${\hat{C}}_p$, ${\hat{C}}_{pk}$ and ${\hat{C}}_{pm}$ of process capability indices $C_p$, $C_{pk}$ and $C_{pm}$. In this paper, we study their asymptotic correlationship for three process capability indices ${\hat{C}}_p$, ${\hat{C}}_{pk}$ and ${\hat{C}}_{pm}$ under bivariate normal distribution BN(${\mu}_x,{\mu}_y,{\sigma}^2_x,{\sigma}^2_y,{\rho}$). With some nonnormal processes, the asymptotic correlation coefficient of any two respective process capability index estimators could be established.

Evaluations of Si based ternary anode materials by using RF/DC magnetron sputtering for lithium ion batteries

  • Hwang, Chang-Muk;Park, Jong-Wan
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.302-303
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    • 2010
  • Generally, the high energy lithium ion batteries depend intimately on the high capacity of electrode materials. For anode materials, the capacity of commercial graphite is unlike to increase much further due to its lower theoretical capacity of 372 mAhg-1. To improve upon graphite-based negative electrode materials for Li-ion rechargeable batteries, alternative anode materials with higher capacity are needed. Therefore, some metal anodes with high theoretic capacity, such as Si, Sn, Ge, Al, and Sb have been studied extensively. This work focuses on ternary Si-M1-M2 composite system, where M1 is Ge that alloys with Li, which has good cyclability and high specific capacity and M2 is Mo that does not alloy with Li. The Si shows the highest gravimetric capacity (up to 4000mAhg-1 for Li21Si5). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. Si thin film is more resistant to fracture than bulk Si because the film is firmly attached to the substrate. Thus, Si film could achieve good cycleability as well as high capacity. To improve the cycle performance of Si, Suzuki et al. prepared two components active (Si)-active(Sn, like Ge) elements film by vacuum deposition, where Sn particles dispersed homogeneously in the Si matrix. This film showed excellent rate capability than pure Si thin film. In this work, second element, Ge shows also high capacity (about 2500mAhg-1 for Li21Ge5) and has good cyclability although it undergoes a large volume change likewise Si. But only Ge does not use the anode due to its costs. Therefore, the electrode should be consisted of moderately Ge contents. Third element, Mo is an element that does not alloys with Li such as Co, Cr, Fe, Mn, Ni, V, Zr. In our previous research work, we have fabricated Si-Mo (active-inactive elements) composite negative electrodes by using RF/DC magnetron sputtering method. The electrodes showed excellent cycle characteristics. The Mo-silicide (inert matrix) dispersed homogeneously in the Si matrix and prevents the active material from aggregating. However, the thicker film than $3\;{\mu}m$ with high Mo contents showed poor cycling performance, which was attributed to the internal stress related to thickness. In order to deal with the large volume expansion of Si anode, great efforts were paid on material design. One of the effective ways is to find suitably three-elements (Si-Ge-Mo) contents. In this study, the Si based composites of 45~65 Si at.% and 23~43 Ge at.%, and 12~32 Mo at.% are evaluated the electrochemical characteristics and cycle performances as an anode. Results from six different compositions of Si-Ge-Mo are presented compared to only the Si and Ge negative electrodes.

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Enhancement of Glucose Oxidation Reaction in Enzyme Biofuel Cell Utilizing Anthracene Dicarboxyl acid Cross-linker (Anthracene dicarboxyl acid 가교제를 활용한 효소연료전지의 산화극의 포도당 산화반응 향상)

  • Hyun, Kyuhwan;Ji, Jungyeon;Kwon, Yongchai
    • Korean Chemical Engineering Research
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    • v.57 no.1
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    • pp.1-4
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    • 2019
  • In this study, an anthracene cross-linker is introduced to enhance the catalytic activity of glucose oxidase (GOx) based catalysts and to increase the amount of enzyme loading. The crosslinked GOx is bonded with the CNT/PEI support using the electrostatic interaction (AC[CNT/PEI/GOx]). Electrochemical evaluations are done to evaluate the performance of this catalyst and the performance of CNT/PEI/GOx catalyst is also measured as a control. According to the measurements, it is confirmed that the amount of loaded GOx increases, while $K_m$ value calculated by Lineweaver-Burk plot shows that AC[CNT/PEI/GOx] ($K_m$ : 0.73 mM) is superior to CNT/PEI/GOx ($K_m$ : 1.71 mM) without cross-linking reaction. Based on these effects, it is demonstrated that the maximum power density of the enzymatic biofuel cell using AC[CNT/PEI/GOx] increases from $21.2{\mu}W/cm^2$ to $57.4{\mu}W/cm^2$.