• 제목/요약/키워드: Uniform Quality

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The influence of implant diameter, length and design changes on implant stability quotient (ISQ) value in artificial bone (임플란트의 직경, 길이 및 디자인변화가 임플란트 안정성지수(ISQ)에 미치는 영향)

  • Lee, Jeong-Yol;Lee, Won-Chang;Kim, Min-Soo;Kim, Jong-Eun;Shin, Sang-Wan
    • The Journal of Korean Academy of Prosthodontics
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    • v.50 no.4
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    • pp.292-298
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    • 2012
  • Purpose: The purpose of this study is to ascertain the stability of the implant by comparing the effects of the change of implant diameter, length and design on implant stability quotient. Materials and methods: To remove the variable due to the difference of bone quality, the uniform density (0.48 g/$cm^3$) Polyuretane foam blocks (Sawbones$^{(R)}$, Pacific Research Laboratories Inc, Vashon, Washington) were used. Implants (Implantium$^{(R)}$, Dentium, Seoul, Korea) were placed with varying diameters (${\phi}3.8$, ${\phi}4.3$ and ${\phi}4.8$) and length (8 mm, 10 mm and 12 mm), to assess the effect on implant stability index (ISQ). Also the influence of the design of the submerged and the non-submerged (SimplelineII$^{(R)}$, Dentium, Seoul, Korea) on ISQ was evaluated. To exclude the influence of insertion torque, a total of 60 implants (n = 10) were placed with same torque to 35 N. Using Osstell$^{TM}$ mentor (Integration Diagnostic AB, Sweden) ISQ values were recorded after measuring the resonant frequency, one-way ANOVA and Tukey HSD test results were analyzed. (${\alpha}$=0.05). Results: 1. The change of the diameter of the implant did not affect the ISQ (P>.05), but the increase of implant length increased the ISQ(P<.001). 2. The change in implant design were correlated with the ISQ, and the ISQ of submerged design was significantly higher than that of the non-submerged design(P<.05). Conclusion: In order to increase implant stability, the longer implant is better to be selected, and on the same length of implant, submerged design is thought to be able to get a higher ISQ than the non-submerged.

Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014 (설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.7
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

Comparison of Noise Power Spectrum Methodologies in Measurements by Using Various Electronic Portal Imaging Devices in Radiation Therapy (방사선치료시 전자포털영상장치를 이용한 잡음전력스펙트럼 방법론 측정비교)

  • Son, Soon-Yong;Choi, Kwan-Woo;Jeong, Hoi-Woun;Kwon, Kyung-Tae;Kim, Ki-Won;Lee, Young-Ah;Son, Jin-Hyun;Min, Jung-Whan
    • Journal of radiological science and technology
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    • v.39 no.1
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    • pp.99-105
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    • 2016
  • The noise power spectrum (NPS) is one of the most general methods for measuring the noise amplitude and the quality of an image acquired from a uniform radiation field. The purpose of this study was to compare different NPS methodologies by using megavoltage X-ray energies. The NPS evaluation methods in diagnostic radiation were applied to therapy using the International Electro-technical Commission standard (IEC 62220-1). Various radiation therapy (RT) devices such as TrueBeam$^{TM}$(Varian), BEAMVIEW$^{PLUS}$(Siemens), iViewGT(Elekta) and Clinac$^R$ iX (Varian) were used. In order to measure the region of interest (ROI) of the NPS, we used the following four factors: the overlapping impact, the non-overlapping impact, the flatness and penumbra. As for NPS results, iViewGT(Elekta) had the higher amplitude of noise, compared to BEAMVIEW$^{PLUS}$ (Siemens), TrueBeam$^{TM}$(Varian) flattening filter, Clinac$^{R}$iXaS1000(Varian) and TrueBeam$^{TM}$(Varian) flattening filter free. The present study revealed that various factors could be employed to produce megavoltage imaging (MVI) of the NPS and as a baseline standard for NPS methodologies control in MVI.

Assessment of Attenuation Correction Techniques with a $^{137}Cs$ Point Source ($^{137}Cs$ 점선원을 이용한 감쇠 보정기법들의 평가)

  • Bong, Jung-Kyun;Kim, Hee-Joung;Son, Hye-Kyoung;Park, Yun-Young;Park, Hae-Joung;Yun, Mi-Jin;Lee, Jong-Doo;Jung, Hae-Jo
    • The Korean Journal of Nuclear Medicine
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    • v.39 no.1
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    • pp.57-68
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    • 2005
  • Purpose: The objective of this study was to assess attenuation correction algorithms with the $^{137}Cs$ point source for the brain positron omission tomography (PET) imaging process. Materials & Methods: Four different types of phantoms were used in this study for testing various types of the attenuation correction techniques. Transmission data of a $^{137}Cs$ point source were acquired after infusing the emission source into phantoms and then the emission data were subsequently acquired in 3D acquisition mode. Scatter corrections were performed with a background tail-fitting algorithm. Emission data were then reconstructed using iterative reconstruction method with a measured (MAC), elliptical (ELAC), segmented (SAC) and remapping (RAC) attenuation correction, respectively. Reconstructed images were then both qualitatively and quantitatively assessed. In addition, reconstructed images of a normal subject were assessed by nuclear medicine physicians. Subtracted images were also compared. Results: ELEC, SAC, and RAC provided a uniform phantom image with less noise for a cylindrical phantom. In contrast, a decrease in intensity at the central portion of the attenuation map was noticed at the result of the MAC. Reconstructed images of Jaszack and Hoffan phantoms presented better quality with RAC and SAC. The attenuation of a skull on images of the normal subject was clearly noticed and the attenuation correction without considering the attenuation of the skull resulted in artificial defects on images of the brain. Conclusion: the complicated and improved attenuation correction methods were needed to obtain the better accuracy of the quantitative brain PET images.

Study on Effect of Convection Current Aeration System on Mixing Characteristics and Water Quality of Reservoir (대류식 순환장치의 저수지수체 유동특성 및 수질영향)

  • Lee, Yo-Sang;Lee, Kwang-Man;Koh, Deok-Koo;Yum, Kyung-Taek
    • Korean Journal of Ecology and Environment
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    • v.42 no.1
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    • pp.85-94
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    • 2009
  • This study examines the operational effectiveness of a Convection Current Aeration System (CCAS) in reservoir. CCAS was run from June, 2008 when the thermocline begun forming in the reservoir. This paper reviews the influence of stratification, dissolved oxygen dynamics and temperature in the lake's natural state from June to October 2008. The survey was done on a week basis. Upwelling flow effects a radius of $7{\sim}10m$ at a surface directly and was irrelevant to the strength of thermocline. On the other hand, it was affected the number of working days, and strength of thermocline at vertical profiles of the reservoir. Longer CCAS run, the deeper was the vertical direct flow area. However it didn't break the thermocline during summer season of 2008. The operating efficiency of the CCAS in the reservoir depends on hydraulics and meteological conditions. Computational Fluid Dynamics (CFD) is a very useful tool for evaluating the operating efficiency of fluid dynamics. The geometry for CFD simulation consists of a cylindrical vessel 25 m radius and 40 m height. The CCAS is located in center of domain. The non-uniform tetrahedral meshes had a bulk of the geometry. The meshes ranged from the coarse to the very fine. This is attributed to the cold water flowing into the downcomer and rising, creating a horizontal flow to the top of the CCAS. The result of CFD demonstrate a closer agreement with surveyed data for temperature and flow velocity. Theoretical dispersion volume were calculated at 8m depth, 120 m diameter working for 30 days and 10 m depth, 130 m diameter working for 50 days.

Inter-ramet Physiological Integration Detected in Buffalograss(Buchloe dactyloides (Nutt.) Engelm.) under Water Stress (수분스트레스 하에 있는 버팔로그래스에서 검출된 무성생식체의 생리학적 조정)

  • Qian, Yongqiang;Li, Deying;Han, Lei;Ju, Guansheng;Liu, Junxiang;Wu, Juying;Sun, Zhenyuan
    • Asian Journal of Turfgrass Science
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    • v.23 no.2
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    • pp.331-344
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    • 2009
  • Buffalograss is an important turfgrass species with excellent cold, heat, and drought tolerance. Understanding the physiological integration of buffalograss under heterogeneous conditions helps to develop cultural practices that better use limited resources for uniform turf quality. The objective of this study was to evaluate physiological integration of buffalograss under water deficit stress and the involvement of lipid peroxidation and antioxidants in the process. In one experiment, buffalograss was planted in the center of a four-compartment growth unit. Watering frequencies, once a week(+) and once in two weeks(-), were combined with the sand(S) or peat(P) in each unit to generate five total treatments(P+S-P-S+, P+P+P+P+, S-S-S-S-, P-P-P-P-, and S+S+S+S+). The average number of shoot established from the heterogeneous root-zone medium was higher than the average of four possible homogeneous media. In second experiment, single ramet in Hoagland solution($S_0$) or single ramet in Hoagland solution with 20% PEG-6000($S_s$) were compared with two connectedramets under different treatments. Treatments for connected ramets were young ramet in Hoagland solution($Y_{os}$) and old ramet in Hoagland solution with 20% PEG-6000($O_{os}$), and old ramet in Hoagland solution($O_{ys}$) and young ramet in Hoagland solution with 20% PEG-6000($Y_{ys}$). Lipid peroxidation, antioxidants, and proline showedphysiological integration between ramets subjected to different levels of water stress. Superoxide dismutase(SOD), Guaiacol peroxidase(G-POD), malondialdehyde(MDA), and free proline also showed different time courses and relative activities during the physiological integration.

Development of Vacuum Puffing Machine for Non-deep Fried Yukwa and Its Puffing Characteristics by Process Variables (비유탕 유과 제조를 위한 진공팽화기의 개발 및 공정변수에 따른 유과의 팽화특성)

  • Yu, Je-Hyeok;Ryu, Gi-Hyung
    • Food Engineering Progress
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    • v.14 no.3
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    • pp.193-201
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    • 2010
  • The aim of this study was to analyse the quality of Yukwa puffed by using a vacuum puffing machine and compare to deep-fried Yukwa. The effect of vacuum puffing condition including heating temperature(100-${160^{\circ}C}$), preheating time(0-8 min) and vacuum puffing time(5-20 min) on physical and microstructure characteristics of the Yukwa was investigated. Vacuum puffed Yukwa at ${100^{\circ}C}$ heating temperature, 6 min preheating time and 10 min puffing time had highest value in volumetric expansion ratio(10.04) and lowest value in bulk density(0.15 g/$cm^{3}$). The breaking strength showed the lowest value of 140 g/$cm^{3}$ in vacuum puffing Yukwa at ${100^{\circ}C}$ heating temperature, 6 min preheating time and 15 min puffing time. The Yukwa puffed with the vacuum puffing machine at ${100^{\circ}C}$ heating temperature, 6 min preheating time and 15 min puffing time had the higher value of bulk density and the lower value of volumetric expansion ratio than those of deep-fried Yukwa. Increasing preheating time and vacuum puffing time caused an increase in white and an decrease in yellowness. The vacuum-puffed Yukwa exhibited smaller and uniform cell structure, while deep-fried Yukwa exhibited apparently in larger pores inside and smaller pores near the surface layer. The optimum condition of vacuum puffing machine for the production of vacuum-puffing Yukwa was ${120^{\circ}C}$ heating temperature, 4 min preheating time and 5 min puffing time.

The Design Improvement Plan of Seoul Forest Visitor Centers for Little Children (서울시 유아숲체험장의 공간 개선 방안)

  • Kim, Minjung;Jeong, Wookju
    • Journal of the Korean Institute of Landscape Architecture
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    • v.49 no.6
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    • pp.49-63
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    • 2021
  • The Forest Visitor Centers for Little Children who means preschoolers is an educational facility that achieves holistic growth by experiencing forests, and it should not be completed by installing specific facilities in the forest environment, but should be a space where preschoolers can play freely in the forest environment themselves. This study comprehensively evaluated the current status of Seoul Forest Visitor Centers for Little Children and suggested space improvement measures to enhance the effectiveness of forest experience. Through the theoretical review, seven spatial elements that enhance the effect of forest experience and six areas composing outdoor play areas were derived to prepare an analysis table for current status evaluation, and field survey studies were conducted on 24 centers in Seoul. Through expert interviews, the physical status was examined from the perspective of childhood education and the experiences of the users were summarized. As a result of the study, the Seoul Forest Visitor Center for Little Children is classified into six types according to the location characteristics and spatial structure, and has the characteristics of each type. The effectiveness of forest experience can be enhanced by identifying and revealing the environmental strengths of individual centers. In the case of outdoor experience learning zones, the proportion of exercise play areas was very large. By evenly organizing the forest experience space for each area, it will be possible to provide more diverse experiences to preschoolers. However, the status of uniform facility-oriented cannot be viewed as a fragmentary factor that lowers the effect of forest experience. The key to increasing the effect of forest experience by inducing creative activities is the spatial composition that considers the surrounding natural environment. Facilities should be a medium to help preschoolers' interest move into the forest. This study prepared data to understand the average physical status of the Seoul Forest Visitor Center for Little Children and suggested space improvement measures to increase the effectiveness of forest experience. This can be used as basic data for research to improve the quality level of the Seoul Forest Visitor Center for Little Children about 10 years after the project was implemented.

Estimation on the Consumption Patterns and Consciousness of Domestic Forage in Korean Native Cattle Farmers (한우 농가 대상 국내산 조사료 이용실태 및 농가 의식조사)

  • Lee, Se Young;Cheon, Dong Won;Park, Hyung Soo;Choi, Ki Choon;Yang, Seung Hak;Lee, Bae Hun;Lee, Byeong U;Jung, Jeong Sung
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.42 no.1
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    • pp.17-25
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    • 2022
  • This study was carried out the estimation on consumption patterns and consciousness of domestic forage for improvement of the quality of domestic forage. Although the cultivated area in South Korea of forage has increased significantly compared to the past, the self-sufficiency rate of domestic forage has increased to around 80% since 2010. Also, livestock farmers prefer to use import forage than domestic due to convenience of use. In Korean beef farms, the ratio of import to domestic forage was higher in domestic forage (import forage 3 : domestic forage 7). In the method of securing domestic forage, purchase of forage (55.6%) was higher than self-cultivation of forage (44.4%). The ratio of use by bailing type was shown in the order of rice staw rice straw (50.5%), domestic hay (15%), imported hay (12.5%), and total mixed ratio (10.7%). The preference of forage was in the order of amount of foreign matter, moisture content, price, feed value in Korean native cattle farm. The result of satisfaction with domestic and import forage showed that the satisfaction of domestic forage price was higher than import forage, while the moisture content and foreign matter of forage were lower than import forage. In addition, in the results of the satisfaction and importance of domestic roughage compared to imported roughage, satisfaction with imported roughage was generally high in all items except for price. As a result, in order to improve the satisfaction of domestic forage in Korean native cattle farm, it is necessary to minimize foreign matter in forage and increase hay production for moisture content uniform in forage.

Investment Priorities and Weight Differences of Impact Investors (임팩트 투자자의 투자 우선순위와 비중 차이에 관한 연구)

  • Yoo, Sung Ho;Hwangbo, Yun
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.18 no.3
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    • pp.17-32
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    • 2023
  • In recent years, the need for social ventures that aim to grow while solving social problems through the efficiency and effectiveness of commercial organizations in the market has increased, while there is a limit to how much the government and the public can do to solve social problems. Against this background, the number of social venture startups is increasing in the domestic startup ecosystem, and interest in impact investors, which are investors in social ventures, is also increasing. Therefore, this research utilized judgment analysis technology to objectively analyze the validity and weight of judgment information based on the cognitive process and decision-making environment in the investment decision-making of impact investors. We proceeded with the research by constructing three classifications; first, investment priorities at the initial investment stage for financial benefit and return on investment as an investor, second, the political skills of the entrepreneurs (teams) for the social impact and ripple power, and social venture coexistence and solidarity, third, the social mission of a social venture that meets the purpose of an impact investment fund. As a result of this research, first of all, the investment decision-making priorities of impact investors are the expertise of the entrepreneur (team), the potential rate of return when the entrepreneur (team) succeeds, and the social mission of the entrepreneur (team). Second, impact investors do not have a uniform understanding of the investment decision-making factors, and the factors that determine investment decisions are different, and there are differences in the degree of the weighting. Third, among the various investment decision-making factors of impact investment, "entrepreneur's (team's) networking ability", "entrepreneur's (team's) social insight", "entrepreneur's (team's) interpersonal influence" was relatively lower than the other four factors. The practical contribution through this research is to help social ventures understand the investment determinant factors of impact investors in the process of financing, and impact investors can be expected to improve the quality of investment decision-making by referring to the judgment cases and analysis of impact investors. The academic contribution is that it empirically investigated the investment priorities and weighting differences of impact investors.

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