• 대한교통학회지
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• 제4권2호
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• pp.3-14
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• 1986

This study was undertaken to develop the gap acceptance model of left-turn drivers on the major road at intersections. Typical unsignalized intersections on the two-lane and four-lane streets in Masan City were selected for the study intersection. For the gap distribution model, the lognormal, negative exponential, shifted negative exponential, and Gamma distributions were tested using the x2 and K-S tests. Based on the results for both streets, it was concluded that among the distributions tested the lognormal distribution represented the gap distribution best, followed by the shifted negative exponential distribution. Stochastic models of the gap-acceptance behavior of left-turn drivers on the major road at unsignalized intersections were programmed using SLAM Ⅱ, a simulation computer language. A stochastic model was selected for the gap-acceptance behavior to compare the results of the simulation with the observed data. The model assumes that a fixed critical acceptance gap is assigned to each left-turn driver based on a normal distribution and the gap distribution of the opposing traffic stream follows the shifted negative exponential distribution.

• 한국전기전자재료학회논문지
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• 제16권10호
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• pp.914-922
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• 2003

The FFS (fringe-field switching) mode was known to exhibit both a wide viewing angle and high transmittance, especially when using a liquid crystal with negative dielectric anisotropy. We have studied cell gap-dependent electrode-optic characteristics of the FFS mode using the LC with negative dielectric anisotropy. In case of a small cell gap of 2 ${\mu}$m, the transmittance at the center of pixel and common electrodes is relatively low because effect of surface anchoring that holds the LC to the initial state is larger than that in a large cell gap of 4 .urn such that the LCs in those regions cannot rotate enough. However, in case of a large cell gap of 4 .urn, the effect of surface anchoring becomes relatively small so that the LCs at the center of pixel and common electrode can be twisted enough by applied voltage, giving rise to high transmittance. Therefore, we can conclude that the light efficiency is dependent on the cell gap.

• 대한전기학회논문지
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• 제32권5호
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• pp.157-163
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• 1983

Positive and negative coronas in point-to-plane short gap have been investigated with the variations of point radius and gap length. Mainly the onset potentials and current pulses under various conditions were measured with a 70 MHz C.R.O. and a precise-controllable D.C. power supply. In the case of negative corona, the Trichel pulse corona, glow corona and spark regions were distinguished apparently and the critical gap lengths between them were also found clearly. In the case of positive corona, there are streamer corona, spark regions and the critical gap length between them, too. The current pulse forms of Trichel pulse corona of negative and streamer pulse corona of positive are similar in rising time, peak-to-peak time and pulse width. The glow corona current shows D.C. component in form.

• Journal of the Optical Society of Korea
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• 제1권2호
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• pp.100-103
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• 1997

We perform degenerate and nondegenerate pump-probe experiments on bulk GaAs at 100 K below the band gap. We mostly observe a negative differential transmission signal both in the degenerate and nondegenerate experiments. We interpret our signal as due to two-photon absorption. This negative signal has a different origin from the normally considered band gap renormalization for resonant excitations.

• BMB Reports
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• 제28권4호
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• pp.316-322
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• 1995

The GTPase activating protein (GAP) can function both as a negative regulator and an effector of $p21^{ras}$. Overexpression of GAP in NIH-3T3 cells has been shown to inhibit transformation by ms or src. To investigate the function of GAP in a differentiative system, we overexpressed this protein in the nerve growth factor (NGF)-responsive PC12 cell line. Two-fold overexpression of GAP caused a delay of several days in the onset of NGF- but not FGF-induced neuronal differentiation of PC12 cells. However, the NGF-induced activation or tyrosine phosphorylation of upstream (Trk, PLC-${\gamma}1$, SHC) and downstream (B-Raf and $p44^{mapk/erk1}$) components of $p21^{ras}$, signalling cascade was not altered by GAP overexpression. Therefore, the change of phenotype induced by GAP was probably not due to GAP functioning as a negative regulator of $p21^{ras}$. Rather, we found that NGF-induced tyrosine phosphorylation of SNT, a specific target of neurotrophin-induced tyrosine kinase activity, was inhibited by GAP overexpression. SNT is thought to function upstream or independent of $p21^{ras}$. Thus in PC12 cells, overexpressed GAP may control the rate of neuronal differentiation through a pathway involving SNT rather than the $p21^{ras}$ signalling pathway.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.539-542
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• 2003

We have studied cell gap-dependent electrode-optic characteristics of the FFS mode using the LC with negative dielectric anisotropy. In case of a small cell gap of 2 ${\mu}m$, the transmittance at the center of pixel and common electrodes is low due to stronger influence of surface anchoring that holds the LC to the initial state than twisting force induced by neighboring LCs. In case of a large cell gap of 4 ${\mu}m$, the influence of surface anchoring force becomes weak so that the LCs at the center of pixel and common electrode can be twisted enough by applied voltage, giving rise to high transmittance. Therefore, we conclude that the light efficiency in the device is dependent on the cell gap.

• 마케팅과학연구
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• 제19권4호
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• pp.1-10
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• 2009

本研究的目的是对咖啡店的 "重要性"（顾客在光顾咖啡店以前的感知）和积极或消极的 "满意度"（顾客在光顾咖啡店以后的感受）之间的差距进行分类, 并分析这些差距对对购买行为的影响. 为此, 我使用重要性和满意度之间的差距作为选择咖啡店的解释变量, 并通过使用有序Probit模型（OPM）来实证分析差距对购买行为（整体满意度和愿意到再次光顾）的影响方向和大小. 先前使用IPA的研究评估了差距影响的方向和大小的象限, 但是在分析差距对顾客的影响方面却失败了. 在本研究中, 我评估了积极和消极的差距对顾客满意度和愿意去再光顾的影响. 通过使用OPM,我量化了积极和消极的差距对顾客整体满意度和愿意去再光顾的影响. 每个人的支出, 光顾的频率和购买咖啡的地方对顾客整体满意度有最积极的影响. 光顾的频率, 在每人的支出之后, 然后是购买咖啡的地方对顾客整体满意度有最积极的影响. 因此每个人的支出和光顾的频率对顾客整体满意度有最积极的影响. 这一发现意味着一个在咖啡店每次或每周花费5000韩元的顾客的实际的满意度越高（差距), 其整体满意度和愿意去再光顾就越高. 虽然经济效益对总体满意度和愿意去再光顾有显著影响, 但是大专和大学的学生仍然愿意去咖啡馆并愿意消费5000韩元, 因为他们不只是购买咖啡本身而且将咖啡店作为其他活动的场所, 例如工作, 和朋友见面或是放松的地方. 学院和大学的学生还可以在咖啡店通过个人电脑上网, 看电影, 学习, 因此, 咖啡馆应对顾客提供适当的设施和服务. 咖啡店品牌的积极差距对愿意去再光顾有积极的影响表明顾客满意度越高, 顾客越愿意去再光顾. 另一方面, 这一因素的消极差距意味着顾客满意度越低, 顾客再光顾的意愿也越低. 因此, 在本研究中, 与其他评估的因素相比, 品牌因素对满意度有较大的影响. 鉴于国内咖啡文化变得越来越高级, 大专院校的学生对这一趋势也很敏感, 所以学生有很多可选择的品牌. 在韩国最高级的咖啡店, 外墙是玻璃建造的并可以打开, 内部是充满异国情调的开放式厨房. 这些高级咖啡店作为标志的功能复合大专院校学生的品味. 韩国咖啡店已成为一个文化品牌. 从品牌因素来看, 为了让顾客觉得这些咖啡店是高级的, 高质量的设备和提供更好服务的措施应当建立起来. 韩国咖啡馆作为蓬勃发展的行业品牌竞争加剧的结果表明, 提供与竞争对手不同的额外服务是有必要的. 顾客可以免费使用扫描仪. 另一个可以用来提高品牌的战略是提供和经营为集体学习而准备的讨论会议室. 如果咖啡馆采取这些类型的策略, 学院/大学的学生将更有可能认为他们承担的费用是值得的, 随后, 他们将可能更满足这些咖啡馆的品牌, 并更愿意再次光顾. 性别和学习年数对总体满意度和再光顾的意愿有最消极的营销. 女学生比男学生更容易满足和再光顾. 三, 四年级的学生比一, 二年级的学生更容易满足和再光顾. 喝咖啡的学生, 单独在咖啡店看书, 用笔记本电脑是很容易被注意到的. 高年级学生为了有效地利用时间用于自我发展和寻找工作往往独自光顾咖啡店. 从积极的差距来看, 经济效率这一因素对总体满意度和愿意再光顾有最大的影响. 与咖啡价格一起, 学生实际满意度（差距）越高, 总体满意度和再光顾的意愿也越高. 有消极差距的经济效率队再光顾有消极营销的结果表明较小的消极差距可以让再光顾的意愿更高. 在持续恶化的市场环境中, 坐落在大专院校附近的咖啡店采取诸如积分或会员卡, 和信用卡 公司的战略联盟, 发展套餐菜单或季节菜单和免费咖啡服务这些战略来提高竞争力. 就消极差距而言产品功率也有消极的影响, 这表明较高的负差距会导致较低的再光顾的意愿. 因为还有更多的客户比前几十年, 在这十年里更喜欢咖啡, 新一代的客户, 即学院/大学的学生, 希望除了咖啡还有更重菜单项目. 因此, 咖啡店应当增加配菜项目, 如华夫饼, 糕, 蛋糕, 三明治和沙拉. 例如, 星巴克韩国正在努力加强卖草莓糕, 艾草香味, 南瓜产品, 并提供免费的咖啡或奶油. 总而言之, 咖啡馆应注重提高其经济效率, 品牌和产品功率, 以加强大专院校学生的满意度. 由于店铺毗邻学大专院校可享受地缘优势, 就经济效率, 品牌和产品功率而言提供不同的服务, 很可能会提高客户满意度和回访. 咖啡厅的品牌, 因此, 应不断创新和变化, 以满足顾客的愿望. 由于这项研究只是针对在首尔的大专院校的学生, 需要针对不同地区和年龄组的比较研究来概括本研究的结果和建议.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1921-1923
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• 2004

V-p characteristics and the discharge luminous characteristics in inhomogeneous $SF_6$ gas gap under the positive and negative lightning impulse voltages are presented. The test gap was composed of the plane-to-plane with a needle-shaped protrusion. The applied voltage and the predischarge current were measured by the electric field sensor and the shunt of 50 ${\Omega}$, respectively. The light emission signals were observed by a photomultiplier tube, and a high-speed camera. In a consequence, the dielectric strengths of $SF_6$ gas gap under positive lightning impulse voltages were independent of the gas pressure. In the presence of the positive polarity, the branches of discharge channel were created and the directions of the discharge paths were random. On the other hands, the discharge paths of the negative polarity were more thicker and brighter.

• 조명전기설비학회논문지
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• 제27권4호
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• pp.73-80
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• 2013

Breakdown characteristics of air in the vertical arrangement of line conductor and plane electrode in case of combustion flame on the plane electrode are examined by the application of AC. and DC voltages to the gap. In order to investigate the effect of paraffin flame on the breakdown characteristics of air, flashover voltages are measured according to the variation of the gap length and the horizontal distance between the flame and the line conductor. As the result of the experiment, flashover voltages are substantially lowered down to 29.8% in case of the AC voltage, and 16.1% in case of the negative DC voltage, when in the presence of the flame. from 100% when in the absence of flame. Flashover voltages of air in the range of smaller than 3㎝ at the horizontal distance are increased in the proportion of the gap length and the horizontal distance in case of both AC and negative DC voltages. But before the flashover occurs, the flame is extinguished by such corona wind that is produced from the line conductor when the gap length and the horizontal distance reach to a certain degree. The effect of relative air density and the phenomenon of thermal ionization are analysed as the reduction factors of flashover voltages, due to high temperature of the flame.

• Journal of Welding and Joining
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• 제21권3호
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• pp.85-91
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• 2003

Narrow gap welding has many advantages over conventional V-grooved butt welding such as high productivity, small deformation and improved mechanical property of joints. With narrower groove gap, less arc heat input is expected will all the other advantages of narrow gap welding. The main defects of narrow gap welding include the lack of root fusion, convex bead surface and irregular surface, all of which have negative effects on the next welding pass. This paper suggests an up-and-down torch oscillation for ultra narrow gap welding with gap size of 5mm and investigates the proper welding conditions to fulfill the reliable and high welding quality. First, GMA welding model was suggested for ultra narrow gap welding system with Halmoy's model referenced for wire melting modeling. And the arc length in ultra narrow gap was defined. Secondly, based on the experimental results of up-and-down torch oscillation welding, phase shift of current and wire extension length were simulated for varying oscillation frequency to show that weld the bead shape in ultra narrow gap welding can be predicted. As the result, it was confirmed that reliable weld quality in ultra narrow gap welding can be achieved with up-and-down torch oscillation above 15Hz due to its ability to provide uniform heat input along the sidewall of gap.