• Journal of Korea Entertainment Industry Association
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• v.13 no.5
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• pp.185-193
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• 2019

Young children facilitate their social and emotional development by doing a lot of play activities with their peers. As an empirical survey study, this study is aimed at analyzing how the peer play interaction influences peer competency and self-regulation. To achieve that, a questionnaire survey was conducted with 271 young children aged 5 years who were going to the kindergarten in the G district of Seoul. With the data collected in the survey, frequency analysis, descriptive statistics, reliability test, correlation analysis and regression analysis were conducted by SPSS program. The analysis results are presented as follows: firstly, peer play interaction positively influenced young children's sociability, pro-sociality, and leadership as their peer competency factors; secondly, peer play interaction positively influenced their patience, endurance of waiting, and adaptation as their self-regulation factors. This study drew the conclusion that peer play interaction is a critical variable to predict young children's peer competency and self-regulation. Therefore, it will be necessary to continuously develop a variety of play activity programs which young children can join in the inside and outside of kindergarten in order to helps young children improve their peer competency and self-regulation, and to actively connect the programs with Nuri curriculum.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.12-18
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• 2023

The effective evacuation strategy according to the accident scenario is crucial to minimize human casualties in the event of toxic gas leak accidents. In this study, the effect of the direction of a building and the location of an industrial complex on the increase in indoor concentration and outdoor diffusion was examined under the same leakage conditions, and effective evacuation criteria were established. In addition, the guidelines for building directions were suggested when constructing buildings that would mitigate human damage caused by chemical accidents. Three scenarios where buildings faced the front, side, and rear of the leakage direction were investigated through CFD simulations. The results revealed that when the building faced the industrial complex, both indoor and outdoor average gas concentrations increased significantly, reaching up to 120 times higher than the other two orientations. Moreover, the indoor space was filled with toxic gas substances more than twice in the same time due to the rapid increase of indoor concentration rate. In cases where the building's windows were positioned at the front, toxic gas stagnation occurred around the building due to pressure differences and reduced flow velocities. Based on our findings, the implementation of these guidelines will contribute to safeguarding residents by minimizing exposure to toxic gas during chemical accidents.

• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.19-26
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• 2024

In workplaces handling flammable gas such as hydrogen, hazardous area is determined through KS C IEC 60079-10-1 standard. Because this standard determines the hazardous distance based on the release characteristic regardless of the type of gas, indoor/outdoor conditions, and atmospheric conditions, concerns are being raised about the effectiveness. In this study, simulations (PHAST, HyRAM) were performed to calculate the hazardous distance for hydrogen under various release characteristics and atmospheric conditions, and compared these results to IEC standard log-log graph. Also, we performed regression analysis according to each result. we found that the simulation results were 0.6 to 3.8 times less than the IEC standard, presented convenient linear regression equations. In addition, We confirmed that the results of hazardous distance varied based on wind velocity and atmospheric stability at the same release characteristic. In addition, we derived linear regression equations for release characteristics and hazardous distance that can be conveniently utilized. So, when classifying hazardous area in workplaces where they handle the hydrogen, the integrated graph and linear regression equation are helpful for confirming the hazardous area. Moreover, it is expected that the economic burden will be minimized by being able to classify reasonable hazardous area and to greatly reduce the risk of hydrogen explosion.

• The Journal of the Acoustical Society of Korea
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• v.43 no.1
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• pp.103-111
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• 2024

Axial-flow fans are used to transport fluids in relatively low-pressure flow regimes, and a variety of design variables are employed. The tip geometry of an axial fan plays a dominant role in its flow and noise performance, and two of the most prominent flow phenomena are the tip vortex and the tip leakage vortex that occur at the tip of the blade. Various studies have been conducted to control these three-dimensional flow structures, and winglet geometries have been developed in the aircraft field to suppress wingtip vortices and increase efficiency. In this study, a numerical and experimental study was conducted to analyze the effect of winglet geometry applied to an axial fan blade for an air conditioner outdoor unit. The unsteady Reynolds-Averaged Navier-Stokes (RANS) equation and the FfocwsWilliams and Hawkings (FW-H) equation were numerically solved based on computational fluid dynamics techniques to analyze the three-dimensional flow structure and flow noise numerically, and the validity of the numerical method was verified by comparison with experimental results. The differences in the formation of tip vortex and tip leakage vortex depending on the winglet geometry were compared through a three-dimensional flow field, and the resulting aerodynamic performance was quantitatively compared. In addition, the effect of winglet geometry on flow noise was evaluated by numerically simulating noise based on the predicted flow field. A prototype of the target fan model was built, and flow and noise experiments were conducted to evaluate the actual performance quantitatively.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.5
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• pp.1075-1084
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• 2024

Efforts to expand the installation of devices that assist visually impaired individuals in their mobility are ongoing, but there are significantly fewer devices installed indoors compared to outdoors, causing considerable inconvenience for indoor navigation. Therefore, this paper aims to address these issues by applying the results of machine learning using YOLO(You Only Look Once) to a Raspberry Pi and by researching techniques to reduce errors through the trilateration method of UWB(Ultra-Wideband) sensors, applying it with a Kalman filter. The research results implemented an object recognition algorithm with a comprehensive accuracy of 91.7% using YOLO technology. Based on this object recognition, the direction (left, right, or front) was determined using the distance difference between two ultrasonic sensors set at an angle difference of 15 degrees. A distance of up to 1.5m was accepted through an infrared sensor to output a warning message according to the distance. The distance between the user's tag and the fixed three anchors was measured indoors through a UWB sensor, and the user's location was also measured indoors by linking the distance value with the three-side positioning technique.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6B
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• pp.565-575
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• 2011

The purpose of this study was to quantitatively evaluate the expression of both multi-metric qualitative habitat evaluation index (QHEI) and biological integrity index (IBI) for artificial structures eco-artificial fish reef (EAFR) for fishes asylum and habitat. Especially, both experimental evaluation and biological verification were performed in Water and Environmental Center's outdoor test-bed of Korea Institute of Construction Technology located in Andong-city, Gyeongsangbuk-do. The experimental conditions reflecting the situation of domestic river include the flow rate (e.g., $0.0{\sim}1.5m\;s^{-1}$), the width (e.g., 1.0~3.0 m), the depth (e.g., 0.05~0.70 m), and variable bed materials. Both QHEI and IBI were monitored for 8 months from May to December 2010. Whereas QHEI values were highest at experimental points of the E~F with an average of 83.1, those were lowest at B~C with an average of 78.1. However, QHEI values inside EAFR were more than 98.9, regardelss of space and time, and indicated more than the highest good of the state (Good) in the habitat. Overally, IBI values showed similar trend with QHEI, but were 44.2 in the winter dry season, compared to 32.8 of QHEI values. IBI values Also, IBI values inside EAFR were greater than those at the experimental channel by 5.7 to 11.4% and 18.7 to 34.8% in flow and stagnant conditions, respectively, indicating that EAFR can secure asylum and habitat for fish during the dry season. For comprehensive aquatic ecosystem assessment, the experimental channel showed generally fair conditions (Fair~Good), whereas EAFR showed good conditions (Good), suggesting that EAFR can be applied to aquatic ecosystem restoration and improvement.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.2 s.308
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• pp.19-29
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• 2006

As the security of personal information is becoming more important in mobile phones, we are starting to apply iris recognition technology to these devices. In conventional iris recognition, magnified iris images are required. For that, it has been necessary to use large magnified zoom & focus lens camera to capture images, but due to the requirement about low size and cost of mobile phones, the zoom & focus lens are difficult to be used. However, with rapid developments and multimedia convergence trends in mobile phones, more and more companies have built mega-pixel cameras into their mobile phones. These devices make it possible to capture a magnified iris image without zoom & focus lens. Although facial images are captured far away from the user using a mega-pixel camera, the captured iris region possesses sufficient pixel information for iris recognition. However, in this case, the eye region should be detected for accurate iris recognition in facial images. So, we propose a new fast iris detection method, which is appropriate for mobile phones based on corneal specular reflection. To detect specular reflection robustly, we propose the theoretical background of estimating the size and brightness of specular reflection based on eye, camera and illuminator models. In addition, we use the successive On/Off scheme of the illuminator to detect the optical/motion blurring and sunlight effect on input image. Experimental results show that total processing time(detecting iris region) is on average 65ms on a Samsung SCH-S2300 (with 150MHz ARM 9 CPU) mobile phone. The rate of correct iris detection is 99% (about indoor images) and 98.5% (about outdoor images).

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.522-529
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• 2013

Climate change will affect the physiological traits and growth of forest trees. This study was conducted to investigate the effects of an experimental warming on growth and physiological characteristics of Pinus densiflora S. et Z. seedlings. One-year-old P. densiflora seedlings were planted in control and warmed plots in April 2010. The air temperature of warmed plots was increased by $3^{\circ}C$ using infrared lamps from November 2010. We measured shoot height, root collar diameter, above and below ground biomass, chlorophyll contents and leaf nitrogen concentration from March 2011 to March 2013. Seedling height and root collar diameter showed no significant difference between warmed and control plots except for root collar diameter measured in June 2012. Seedling leaf biomass was lower in the warmed ($23.94{\pm}2.10g$) than in the control ($26.08{\pm}1.72g$) plots in 2013. Shoot to root ratio (S/R ratio) was lower in the warmed ($1.09{\pm}0.07$) than in the control ($1.31{\pm}0.10$) plots in 2013. Leaf nitrogen concentrations and chlorophyll contents were not significantly different between warmed and control plots except for leaf nitrogen concentration in 2011. Leaf C/N ratio was increased in 2012 under the warming treatment. Low growth and S/R ratio in warmed plots might be related to the higher temperature and water stress. In the future, the below-ground carbon allocation of P. densiflora might be increased by global warming due to temperature and water stress.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2002.11a
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• pp.59-63
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• 2002

1997년 홍콩 가금시장에서의 H5N1 조류독감바이러스의 발병은 18명의 감염된 사람 중에서 6명의 사람의 생명을 앗아갔다. 이 사건은 조류독감바이러스가 매개체를 통하지 않고 닭에서 바로 사람에게 감염한 처음 있는 사건이다. 홍콩가금시장에서의 역학조사는 H5Nl과 H9N2 조류독감바이러스가 함께 공존한다는 것을 밝혔다. 가금에서는 H5N1과 H9N2 조류독감바이러스가 검출되었다. 우리는 H5N1 조류독감바이러스로부터 자을 방어하는데 H9N2 조류독감바이러스의 역할에 대해 연구했다. H5N1과 H9N2 바이러스의 혼합바이러스를 동시에 자에 접종하면 자은 생존하지 못했다. 그러나, H5N1 조류 독감바이러스감염 이전에 H9N2 조류독감바이러스를 감염한 닭들은 생존할 수 있었다 H9N2 조류 독감바이러스로 감염된 닭으로부터 얻어진 혈청은 H5N1 조류독감바이러스와 교차반응을 일으키지 않는다. H9N2 조류독감바이러스로 감염시킨 닭으로부터 얻어진 T임파구 또는 CD8 T임파구를 감염하지 않은 닭에 주입할 때 닭은 H5N1 조류독감바이러스로부터 생존할 수 있었다. 실험실외 킬러임파구실험은 H9N2 조류독감바이러스로 감염된 닭으로부터 얻어진 T임파구는 H5N1과 H9N2 조류독감바이러스로 감염된 목표세포를 동시에 감지했다. 게다가, 생체내 T임파구의 제거실험은 교차보호면역은 a/b TCR를 가진 CD8 T임파구가 중요한 역할을 하며, a/b TCR (Vbl)형의 T임파구가 목표세포를 감지한다는 것을 증명했다. H9N2 조류독감바이러스에 의한 방어면역은 시간이 지남에 따라 감소를 했고, 감염 100일까지 방어력을 나타냈다. 1997년 조류독감바이러스인 H5N1의 홍콩에서의 발병에 대한 풀리지 않은 것 중의 하나는 약 20%의 조류들이 매우 치사율이 높은 H5N1 독감바이러스를 가지고 있음에도 홍콩가금시장에서의 대부분의 닭들은 건강했다. 얻을 수 있는 정보에 따르면 대부분의 자들은 H5N1조류독감바이러스를 변으로 방출했고, 단지 두 곳의 가금시장에 있는 자들이 질병증상을 보였다. 홍콩가금시장에서 분리된 모든 H5N1 조류독감바이러스를 닭에 감염하면 100%의 치사율을 나타낸다. 바이러스 측면에서의 연구에 따르면, H9N2 조류독감바이러스는 홍콩가금시장에서 두 번째로 많이 분리되었다. H9N2 조류독감바이러스에 대한 연구에 따르면 세 가지 형이 홍콩가금시장에서 검출되었다. 1997년에 가장 많이 분리된 H9N2 조류독감바이러스는 PB1과 PB2가 A/Chicken/HongKong /156/97 (H5N1)과 유전적으로 유사한 A/HongKong/G9/97 (H9N2)형이다. A/Chicken/Hong Kong/156/97(H5N1)의 나머지 유전자는 A/Chicken/HongKong/739/94 (H9N2)와 A/chicken /Hong Kong/G23/97의 유전자와 비슷하다. 하나의 A/Quail/Hong Kong/G1/97은 Quail에서 분리되었고, 두 개의 A/Duck/Hong Kong/Y280/97 (H9N2)은 오리에서 분리되었다. A/Quail/Hong Kong/G1/97 (H9N2)의 6개의 내부유전자는 A/HongKon9/156/97 (H5N1)에 유사하나, A/Duck/ Hongkong/Y280/97 (H9N2)의 유전자는 A/HongKong/156/97 (H5N1)과 유사하지 않다. 킬러임파구는 바이러스로 감염된 목표세포를 MHC에 의존하여 파괴한다. 독감바이러스 특이 킬러임파구는 독감바이러스로 감염된 mice의 폐로부터 독감바이러스를 제거하는데 중요하다고 알려져 있다. 독감바이러스의 HA단백질은 특이 킬러임파구의 주요 목표항원 단백질이 아니다. 내부단백질인 nucleoprotein, polymerase (PB1 PB2, PA), Matrix protein, 그리고 비 구조단백질인 NS1에 대한 특이 킬러임파구의 반응이 사람과 mice에서 보고되었다. 독감바이러스에 대한 mice의 킬러임파구의 인식영역은 제한되어 있다고 알려져 있다. 많은 mice MHC 1은 독감바이러스 단백질의 킬러임파구의 epitope를 표현하지 못한다. 사람 기억킬러임파구는 다양한 종류의 독감바이러스의 단백질을 인식한다고 알려져 있다. 지금까지, 닭에서의 독감바이러스의 킬러임파구에 대한 연구는 되지 않았다.

• Journal of Preventive Medicine and Public Health
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• v.29 no.3 s.54
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• pp.693-700
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• 1996

The purpose of this study was to determine whether workers at a factory next to a lead recycling factory in Pusan, were affected by lead contamination. The mean air lead concentration of lead recycling factory was $0.21mg/m^3(TWA=0.05mg/m^3)$. Thirty-nine male workers of Factory A, Cr. plating factory next to the lead recycling factory were exposed group and a comparison group, 62 male workers of Factory B were selected from another Cr. plating factory about 8.5km away from lead recycling factory. Air lead concentration of each workplace was checked for 4 times from August f to August 20 in 1995 by low volume air sampler. Each subject was interviewed about age, life-style, smoking, work history, and residence etc, and venous blood was drawn for lead measurement by graphite furnace atomic absorption spectrometry. We have observed that air lead concentration and blood lead concentration of Factory A was higher than Factory $B(2.6{\pm}1.6\;Vs.\;1.2{\pm}0.2{\mu}g/m^3,\;14.9{\pm}1.6\;Vs.\;12.2{\pm}1.6{\mu}g/dl)$. We believe that other environmental lead sources such as transportation and residence did not affect air lead and blood lead concentration differences of both factory. We concluded that high air lead and blood lead concentration of Factory A were caused by lead contamination generated by the neighboring lead recycling factory.