• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.1
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• pp.26-34
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• 2014

This study focuses on development of a risk level evaluation model for the intersection dilemma zone based on vehicle speed distribution approaching the intersection. The study results show that dilemma zone exists for all approaches selected for the study because the values of amber time have not been properly set, and that re-optimized values significantly reduce the dilemma zone risk level. It is also found that when normal distribution is assumed for vehicle approach speed the risk values similar to those for actual speed distributions can be obtained. When the risk level is found to be high, the amber time must be adjusted to reduce the length of the dilemma zone, or speed calming measures must be introduced so that vehicle speed be maintained under the speed value used when determining the amber time.

• Journal of Periodontal and Implant Science
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• v.32 no.3
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• pp.685-695
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• 2002

황색 포도상구균은 급성 구강 감염에 있어서의 병원균이다. 그러나 그러한 황색 포도상구균의 병원성 기전은 완전히 이해되지 않았다. 이전 실험에서 황색 포도상구균의 단백질 A와 골격근의 액틴 필라멘트는 인체 상피 세포로의 황색 포도상구균의 침입에 관여한다. 구강 내 감염에 있어서의 황색 포도상구균의 병원성 기전을 조사하기 위해 인체의 치은 섬유모 세포에 대한 침입이 연구되고 있다. 급성 구강 감염을 가진 환자로부터 분리된 ATCC 25923 황색 포도상구균과 OPT 2 황색 포도상구균의 침입은 시간(0-120분)에 의존한다는 사실을 밝혀냈다. 60분을 초과하는 배양시간은 다시 배양된 균집락수 증가를 가져왔다. 배지에 접종한 세균의 숫자가 증가할 때 (100?10,000,000 cfu/ml/well), 직선적으로 증가한다. 단백질 A가 결핍된 Wood 46 황색 포도상구균의 침입은 단백질 A가 발현된 균주(ATCC 25923과 OPT 2)의 침입보다 훨씬 낮았다. 액틴 필라멘트의 합성을 방해하는 Cytochalasin D는 인체 치은 섬유모세포로 황색 포도상구균 (ATCC 25923과 OPT 2)이 침입하는 것을 방해한다. 이러한 결과는 구강내 감염을 일으키는 황색 포도상구균의 병원성 기전이 세포내 침입에 관여하고, 황색 포도상구균 단백질 A와 골격근의 액틴 필라멘트가 인체 치은 섬유모세포로의 황색 포도상구균의 침입 조절에 관여한다는 것을 보여준다.

• The Korean Journal of Food And Nutrition
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• v.10 no.2
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• pp.241-245
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• 1997

In order to make natural food color from Gardenia, we investigated optimal conditions of color extraction, and thermal stability and light stability of color extracted compared with Yellow-4. In case of ethanol extraction, optimal conditions for color extraction were substrate 10%, 4$0^{\circ}C$, pH 7.0 and 42rs, respectively. In case of water extraction, optimal conditions for color extraction were substrate 10%, 7$0^{\circ}C$, pH 7.0 and 48hrs, respectively. Extraction yield in the optimal conditions was 75% in ethanol and 63% in water. The thermal stability and light stability of Yellow-4 were both upper 98%, but those of Gardenia yellow color were 62 and 90%, respectively.

• Tuberculosis and Respiratory Diseases
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• v.64 no.1
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• pp.22-27
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• 2008

Background: Staphylococcus aureus frequently colonizes and infects hospitalized patients. Respiratory infections with Staphylococcus aureus are common in patients with compromised airway defenses. However the mechanisms of S. aureus invasion from colonization to the epithelium are unclear. Cell invasion by S. aureus would require destruction of the extracellular matrix, which is believed to be the result of increased matrix metalloproteinases (MMP) activity. Methods: In this study, respiratory epithelial cells were infected with S. aureus. After removing the extracellular bacteria by washing, the internalized bacteria in the cells were assessed by counting the colonized forming units (CFUs). The cell adhesion proteins, dysadherin and E-cadherin, were evaluated by Western blotting. The MMPs in the bacterial invasion were evaluated by pretreating the cells with GM6001, a MMP inhibitor. Results: The internalization of S. aureus was found to be both time and dose dependent, and the increase in MMP 2 and 9 activity was also dependent on the incubation time and the initial amount of bacterial inoculation. The invasion of S. aureus was attenuated by GM6001 after 12 hours incubation with a multiply of infection (MOI)=50. The expression of dysadherin, a membrane protein, was increased in a time and dose dependent manner, while the expression of E-cadherin was decreased. Conclusion: MMPs may mediate the invasion of S. aureus into epithelial cells.

• Journal of Food Hygiene and Safety
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• v.19 no.1
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• pp.49-54
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• 2004

The prevention of infectious disease from contaminated foods is very important in public health. Quantitative microbial risk assessment has been used in advance countries to achieve the safety of public health against hazardous microbial causing contaminated foods. This study was conducted to estimate maximum edible time without producing enterotoxin from Staphylococcus aureus in Kimbap selling at different domestic store using Food MicroModel and monitoring data and to compute maximum edible time by temperature with 99th percentile safety probability based on only restaurant data. For estimating maximum edible time, model operation conditions like reaching time at 2 ${\times}$ 10$^{7}$ , which enterotoxin was known as producing point from S. aureus, temperature of 28∼3$0^{\circ}C$, pH 5.2, NaCl 0.22%, aw(water activity) 0.99, and intaking one serving size of 171g in Kimbap were considered. Estimated maximum edible times by regarding outdoor temperature in summer were 3.9∼4.6 hrs in restaurant, 6.7∼7.9 hrs in department store and 7.4∼8.7 hrs in convenient store. Based on restaurant data, estimated maximum edible times with 99th percentile safety probability by temperature were 1.9 hrs in 3$0^{\circ}C$ and 17.7 hrs in 15$^{\circ}C$.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.4
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• pp.14-34
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• 2023

The purpose of this study was to calculate the appropriate yellow-signal time for intersections, to find out the relationship between the approach speed and intersection width when calculating the time, and to secure safety by minimizing conflicts and dilemma sections in intersections that change according to the signal operation. For this purpose, 6,824 data points from 5 intersections were collected and analyzed. The main results of the study are as follows. First, the approach speed of individual vehicles in different lanes was analyzed, and the width of an intersection was defined by considering the conflict in each direction. Second, we developed a multiple regression model based on the approach speed and conflict points, which compensated for the problems of an existing formula. Third, a standard table is presented for applying the appropriate yellow-signal time according to the approach speed and intersection width based on a development formula. A method is also presented to determine the safety of the length of the dilemma according to the change in the yellow-light time by presenting a calculation table that can cross-analyze the yellow-signal time and a dilemma section using the relationship.

• Proceedings of the KOR-KST Conference
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• 2007.05a
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• pp.300-309
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• 2007

본 연구는 신호교차로에서의 딜레마 죤 범위를 산정하고 신호위반 단속의 허용 범위를 분석하는데 있다. 각 교차로 접근로별 조사 자료를 토대로 딜레마 죤의 범위를 산정하였고, 이를 토대로 신호위반 단속에 있어 딜레마 죤의 영향을 최소화 할 수 있는 방안을 제시하고자 하였다. 기존의 딜레마 죤에 관한 연구에서는 인지-반응 시간과 황색신호시간을 초기값으로 적용하였으나 본 연구에서는 해당 교차로의 조사치를 적용하였다. 조사 방법으로 속도조사는 스피드 건을 이용하여 각각의 대상 교차로별 접근로에서 접근 속도 및 통과 속도를 조사하였으며, 운전자의 인지-반응 시간 및 황색신호시간에 교차로를 통과하는 차량조사는 비디오 촬영을 통하여 조사하였다. 이러한 조사된 자료를 토대로 신호위반 단속기준에 맞추어 딜레마 죤에 관하여 분석하였다. 본 연구에서 딜레마 죤은 최소정지거리($d_0$)가 최대통과거리($d_c$)보다 클 때 존재하는 것으로 보았으며, 그 차이만큼의 딜레마 죤이 발생하는 것으로 정의하였다. 이에 신호위반 단속을 함에 있어딜레마 죤의 영향을 최소화 할 수 있는 방안 등을 제시하였다. 그러나 각각의 방안을 개별적으로 적용시킬 경우 문제점이 발생하였다. 이러한 문제점을 해결하기 위해서 자기감응식 루프검지기의 위치를 재조정함에 있어 하나의 루프 검지기를 정지선 이후에 존재함과 동시에 황색신호시간을 재조정하거나, 자기감응식 루프검지기의 작동시간을 재조정하는 방안을 제시하고자 하였다. 본 연구에서는 3개의 교차로를 비교대상으로 선정하여 각각의 교통환경에 따른 접근로별 딜레마죤의 범위를 최소화하기 위한 대안을 제시하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.296-301
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• 2020

Three types of traffic signal systems are two-color signal systems that flash red and green and are mainly used on crosswalks, next, three-color equalization systems mainly used at T-shaped intersections with red and yellow lights and a green arrow, and third, four-color intersections that generally have red, yellow and green colored lights and a green arrow. In what is known as the "dilemma zone" area, a driver collects information that influences his/her decision whether to stop, speed, tail, interrupt, or violate a traffic light, depending on the intersection width, vehicle speed, cognitive response time and reference yellow signal time. This study examined the impact of changes in the length of the dilemma zone areas based on changes in yellow signal times, the speed of the intersection passages, and signal lamps. Downward adjustments of 50km/h and 60km/h affected yellow signal time. The yellow signal time increased by 0.1 to 2.3[s] due to this effect and the dilemma zone area increased by 1.22 to 26[m]. The driver of the dilemma zone could quickly decide to reduce the time remaining of the straight (3color, 4color) green signal to reduce the potential of a traffic accident at the intersection traffic. Safe entry of red (LED palm) and left-turn signals for entering flashed at the intersection and operated at midnight.

• Journal of the Korean Home Economics Association
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• v.46 no.7
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• pp.1-6
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• 2008

The purpose of this study was to investigate the changes in properties of silk fabrics dyed with safflower red and yellow colorants under Ultraviolet(UV)-light. Silk fabrics dyed with safflower red and yellow colorants were compared with each other after uv-light exposure in terms of K/S value, color changes(${\Delta}E$), morphology, and strength retention. The K/S value rapidly decreased with increasing exposure time for samples of both colorants, but the extent of decrease was less for the samples dyed with safflower yellow colorant, than that of the samples dyed with safflower red colorant. Regarding the color changes with increasing exposure time, $L^*$ and $b^*$ increased, $a^*$ decreased, and thereby ${\Delta}E$ increased in the red-dyed samples, whereas $L^*$ increased, $a^*$ and $b^*$ decreased, and so ${\Delta}E$ increased in the yellow-dyed samples, indicating that the UV-light induced fading and changes of hue, value and chroma value. However, the color change of the yellow-dyed samples was less than that of the red-dyed samples. SEM images showed a severe degradation by UV-exposure for both colorant samples. Tensile strength slowly decreased until 14 days, but rapidly decreased thereafter. Strength retention of the yellow-dyed samples was higher than that of red-dyed samples.

• Journal of the Korean Home Economics Association
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• v.46 no.9
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• pp.1-6
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• 2008

The purpose of this study was to investigate the changes in the property of nylon fabrics dyed with safflower red and yellow colorants under Ultraviolet(UV)-light. For this purpose, nylon fabrics dyed with safflower red and yellow colorants were compared with each other after uv-light exposure in terms of K/S value, color changes(${\Delta}E$), morphology, and strength retention. K/S value rapidly decreased with increasing exposure time, but K/S value of the samples dyed with safflower red colorants decreased less than that of samples dyed with safflower yellow colorants. In color changes, as increasing exposure time, $L^*$ increased, $a^*$ decreased, $b^*$ increased, and so ${\Delta}E$ increased in samples dyed with safflower red colorants. In color changes, as increasing exposure time, $L^*$ increased, $a^*$ and $b^*$ decreased, and thereby ${\Delta}E$ increased in the samples dyed with safflower yellow colorants, indicating fading away by uv-light and changes of hue, value and chroma value. But the color change of samples dyed with safflower yellow colorants was less than that of samples dyed with safflower red colorants. SEM pictures showed a severe degradation by uv exposure, regardless of colorants type. Tensile strength slowly decreased until 14 days, and rapidly decreased until 28 days. Strength retention of the samples dyed with safflower yellow colorants was higher than that of the samples dyed with safflower red colorants.