• Journal of Biosystems Engineering
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• v.34 no.1
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• pp.63-68
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• 2009

This study was carried out to determine necessary conditions for optimal ventilation of small windowless piglet house (5.2 (W) ${\times}$ 12.3 (L) ${\times}$ 2.3 (H) m) with negative tunnel ventilating system using CFD (Computational Fluid Dynamics) simulation. The weaning piglet house for this experiment was consisted of 4 rooms (520 (W) ${\times}$ 300 (L) cm), 3 fences (70 (H) cm), 1 air inlet (350 (W) ${\times}$ 2 (H) cm) and 1 exhaust fan (50 (D) cm), and simulated using CFD code, FLUENT. The simulation results for the original weaning piglet house showed ununiform ventilation for each room. Therefore, to uniformly ventilate all rooms, the heights of the air inlet and first fence were modified to 3 cm and 100 cm, respectively. The simulation result f3r the modified weaning piglet house showed uniform ventilation for all rooms and the optimum air inlet velocity of 1.4 m/s.

• Journal of Internet Computing and Services
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• v.4 no.6
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• pp.75-86
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• 2003

In main-memory resident index structures, secondary cache misses considerably have an effect on the performance of index structures. Recently, several main-memory resident index structures that consider cache have been proposed to reduce the impact of secondary cache misses. However they still suffer from full secondary cache misses whenever visiting each level of a index tree, In this paper, we propose a new index structure that eliminates cache misses even when visiting each level of index tree. The proposed index structure prefetches the grandchildren of a current node. The basic structure of the proposed index structure is from CSB+-tree that uses the concepts of the node group to increase fan-out. However the insert algorithm of the proposed index structure reduces the cost of a split significantly, Also, we show the superiority of our algorithm through various performance evaluation.

• Structural Engineering and Mechanics
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• v.76 no.2
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• pp.153-162
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• 2020

Aiming at the mechanical and structural characteristics of the contact zone composite rock, the shear tests and numerical studies were carried out. The effects of the differences in mechanical properties of different materials and the normal stress on shear properties of contact zone composite samples were analyzed from a macro-meso level. The results show that the composite samples have high shear strength, and the interface of different materials has strong adhesion. The differences in mechanical properties of materials weakens the shear strength and increase the shear brittleness of the sample, while normal stress will inhibit these effect. Under low/high normal stress, the sample show two failure modes, at the meso-damage level: elastic-shearing-frictional sliding and elastic-extrusion wear. This is mainly controlled by the contact and friction state of the material after damage. The secondary failure of undulating structure under normal-shear stress is the nature of extrusion wear, which is positively correlated to the normal stress and the degree of difference in mechanical properties of different materials. The increase of the mechanical difference of the sample will enhance the shear brittleness under lower normal stress and the shear interaction under higher normal stress.

• Journal of Microbiology and Biotechnology
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• v.30 no.7
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• pp.1072-1081
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• 2020

Screening suitable strains with high temperature adaptability is of great importance for reducing the cost of temperature control in microalgae cultivation, especially in summer. To obtain high temperature-tolerant diatoms, water samples were collected in summer from 7 different regions of China across the Northeast, North and East. A total of 731 water samples was collected and from them 131 diatom strains were isolated and identified based on the 18S rRNA sequences. Forty-nine strains out of the 131 diatoms could survive at 30℃, and 6 strains with relatively high biomass and lipid content at high temperature were selected and were found to be able to grow at 35℃. Cyclotella sp. HB162 had the highest dry biomass of 0.46 g/l and relatively high triacylglycerol (TAG) content of 237.4 mg/g dry biomass. The highest TAG content of 246.4 mg/g dry biomass was obtained in Fistulifera sp. HB236, while Nitzschia palea HB170 had high dry biomass (0.33 g/l) but relatively low TAG content (105.9 mg/g dry biomass). N. palea HB170 and Fistulifera sp. HB236 presented relatively stable growth rates and lipid yields under fluctuating temperatures ranging from 28 to 35℃, while Cyclotella HB162 maintained high lipid yield at temperatures below 25℃. The percentage of saturated fatty acids and monounsaturated fatty acids in all the 6 strains was 84-91% in total lipids and 90-94% in TAGs, which makes them the ideal feedstock for biodiesel.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.407-412
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• 2014

Purpose: It is investigated whether the time division system can extend the field without diplopia for people with homonymous hemianopia. Methods: The time division system was manufactured by a modified mini fan and a black cardboard. In order to verify the effectiveness of the equipment, subjects with and without the equipment took part in the experiment to bisect the space and to recognize letters. Results: Subjects with and without the equipment showed +8.91 and +18.14 degrees in the experiment to bisect the space. In the experiment reading the letters and numbers with the equipment, there were 9 percentage point increase in $4{\times}4$ charts and 15 percentage point increase in $6{\times}6$ charts. It turned out that there was a remarkable improvement for the worst group for reading the charts. Conclusions: The time division system is effective in the mobility and orientation for people with homonymous hemianopia.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.950-958
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• 2014

According to the rapid spreading of smart phone, the use of social network service(SNS) is also increasing rapidly. Social network service(SNS) which plays an important role in customer relationship management and brand management is becoming more important. This study aims to find out if differences exist in the perceptions of service quality and the consumer behaviors between Korean and Chinese consumers using SNS. In order to achieve the objectives of the study, the literatures of service quality and consumer behavior theory is reviewed. And based on the literature reviews, dimensions related to service quality and consumer behavior are derived and T-test is used to identify the differences. According to the analysis, significant differences exist in the perceptions of service quality and consumer behaviors between Korean and Chinese consumers using SNS. The results not only provide theoretical evidences for further SNS study but also provide practical evidences for companies in their overseas expansion.

• Korean Journal of Human Ecology
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• v.17 no.1
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• pp.171-179
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• 2008

This study focuses on 130 estheticians currently working in and around Daegu and Gyeongbuk region, in order to find out the current state of affairs and side effects related to aromatherapy. This paper is based on a survey. SPSS win 11.0 program was used for the analysis of descriptive statistics and independent t-test. According to the result of analysis, about 33% of the estheticians have had allergy experience. And in terms of installation of an air ventilation fan, which is the most important facility in an treatment room, more than half (50.8%) replied they did not have one. There was a statistically significant difference between those estheticians suffering from allergy and those who did not, in symptoms of stuffy nose/rhinitis (P<0.01) and dry skin/itchiness (P<0.5). (Allergy symptoms from the 33% of estheticians were limited to those which occurred after he or she began career) On work related symptoms, those who had work history at hospitals/clinics or apothecaries were compared. A statistically relevant difference was confirmed between those estheticians with therapy experience and those who had none, in all symptoms except headaches and drowsiness/weariness. In other words, there was difference in symptoms such as dryness of skin/itchiness (P<0.01), stuffy nose/rhinitis, dry throat, tension/nervousness, dizziness, tired eyes(P<0.5), nausea, having trouble with focusing, and fatigue(P<0.1). Those estheticians who had a history of treatment especially suffered most from dryness of skin and itchiness. The rate of regular check-ups and the use of masks, employed for self protection, was lower than average (amounting to 5 points), with the use of masks especially having the lowest average (1.7) points.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.130-139
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• 2009

This paper introduces the secondary cultural productions of game fandom that have been underestimated. The participatory cultural activities of game users are broadly expanding owing to machinima technology based on game engine. It allows gamers to make the three dimensional digital animations simple and easy way. This paper studies that how simple game consumers change their role as producers through machinima. This study is focused on the relationship between polysemy of participatory Machinima and former fandom's the secondary culture studies using ethnographic research method. It is to clarify relationship between the game users' psychological motivation for culture practice and the machinimas. We verify practically the machinima's effects on fandom culture through analysing viewers' reaction using replies on the machinimas and then find out machinima is a very important tool for expanding the game culture realm as the main body.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.4
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• pp.361-369
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• 2017

In this study, the characteristics of the dust emission according to the presence or absence of operation of the gas stove were analyzed by particle size analysis and density estimation while the mackerel was cooked while the fan was placed on the gas stove used in the home. The experiment was carried out using 20 mackerel of normal size at home. Commercially available canola oil was used as edible oil. In order to understand the characteristics such as particle size distribution of fine dust, light scattering measurement method which can be measured at intervals of several seconds was used. Particles generated by combustion of gas stove, particles formed by heating cooking oil, and particles generated by heating mackerel fish meat are judged to be nano size particles smaller than $1{\mu}m$. Therefore, it is necessary to use precise measurement method rather than the measurement method using the filter which is currently being measured in the measurement of the particles discharged from the fuel combustion or food cooking in the future. Analyzing the particle size and density of the dust emitted from the cooking stove is expected to contribute technically to the reduction of dust emissions from the cooking process of gas and fuel facilities at home and commercial facilities.

• Journal of Microbiology and Biotechnology
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• v.26 no.7
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• pp.1173-1181
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• 2016

Salmonella spp. are gram-negative flagellated bacteria that cause a variety of diseases in humans and animals, ranging from mild gastroenteritis to severe systemic infection. To explore development of a potent vaccine against Salmonella infections, the gene encoding outer membrane protein L (ompL) was inserted into the swinepox virus (SPV) genome by homologous recombination. PCR, western blot, and immunofluorescence assays were used to verify the recombinant swinepox virus rSPV-OmpL. The immune responses and protection efficacy of rSPV-OmpL were assessed in a mouse model. Forty mice were assigned to four groups, which were immunized with rSPV-OmpL, inactive Salmonella (positive control), wild-type SPV (wtSPV; negative control), or PBS (challenge control), respectively. The OmpL-specific antibody in the rSPV-OmpL-immunized group increased dramatically and continuously over time post-vaccination, and was present at a significantly higher level than in the positive control group (p < 0.05). The concentrations of IFN-γ and IL-4, which represent Th1-type and Th2-type cytokine responses, were significantly higher (p < 0.05) in the rSPV-OmpL-vaccinated group than in the other three groups. After intraperitoneal challenge with a lethal dose of Salmonella typhimurium CVCC542, eight out of ten mice in the rSPV-OmpL-vaccinated group were protected, whereas all the mice in the negative control and challenge control groups died within 3 days. Passive immune protection assays showed that hyperimmune sera against OmpL could provide mice with effective protection against challenge from S. typhimurium. The recombinant swinepox virus rSPV-OmpL might serve as a promising vaccine against Salmonella infection.