• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.14 no.6
• /
• pp.131-141
• /
• 2019

This paper investigates a relationship between a market position of a venture capitalist(i.e.,VC) and its subsequent performance. Although a VC firm may perform better if it occupies a narrow niche(e.g.,specialist), which allows the firm to attain deep insider knowledge and build an identity as an industry expert, a firm may perform better if it has a broader niche(e.g.,generalist), which gives the firm access to more diverse information and opportunities and to effectively spread out potential risks. Given that accesses to valuable information and chances are critical for success in venture capital industry, we hypothesize that venture capitalists with broad niche width are more likely to grow in the future and analyze 26-year data on US venture capital industry. We found that, in general, a firm can enjoy the advantage of having a broad niche. However, the return to having a broad niche varies depending on its status within the market: a return greater for low- status than high-status VC firms. Our finding suggests that explorative efforts may be more rewarding for low-status VC firms.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.11 no.2
• /
• pp.92-97
• /
• 2008

Salt wedge into the river from the sea or fresh water flume (fresh wedge) in the ocean from the sea has density current characteristics. However, when temperature and salinity simultaneously determine the density of wedges, one of salinity and temperature can distributed in the reversed profiles against gravity, even though the density profile is stable. In this case, the double diffusive process is critical in determining mixing rate. The present work studies relative contribution of shear driven mechanical mixing component and double diffusive layering process, when warm salty denser water is introduced into the cold fresh lighter water column. Laboratory experiment releases warm salty denser water into cold fresh lighter water controlling discharge amount to achieve the steady state of density current. When longitudinal density rate becomes 15, the released amount ratio of salt and heat changes sharply and in the releasing point, vigorous mixing occurs with increase of discharged amount due to double diffusion. Double diffusion distabilizes gravitational stability and enhances the mixing rate up to $6{\times}10$ times at the lower density ratio comparing to the higher density ratio.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.1822-1826
• /
• 2009

최근 국내 하천복원사업의 방향(패러다임)이 구하도를 포함한 홍수터의 중요성을 인식하게 됨에따라 과거 하천사업 시 발생되었던 폐천구역을 가능한 한 하천구역에 편입하여 보존하려는 노력이 시도되고 있다. 본 연구는 하천복원사업의 일환으로 함평천 구하도 복원을 함으로써 발생할 수 있는 흐름특성변화 및 하상변화를 파악하기 위한 목적으로 수리모형실험과 수치모의를 수행하였다. 실험대상구간은 함평천 중류 구하도 복원구간(1.34 km)이며, 수리모형은 Froude 상사법칙에 따라 수평축척 1/50, 연직축척 1/25의 모형으로 제작하였다. 실험조건으로는 재현기간 50년, 100년의 홍수량과 강턱유량 두 케이스$(100\;m^3/s$, $120\;m^3/s)$를 적용하였고, 구하도 복원수로의 흐름특성은 고정상 조건에 대해 분석하였다. 구하도 복원전/후의 홍수위 비교를 통해 구하도 복원후의 하도에서는 단면확대로 인한 통수능 증가로 홍수위 저감효과를 확인 할 수 있었다. 구하도 복원후의 유속변화는 통수능의 증가로 복원전에 비해 저감되었다. 기존하도와 복원하도간의 유속차가 다소 크게 나타났는데 이는 복원하도의 단면형상과 와류발생으로 인해 나타난 것으로 판단된다. 복원하도내의 유황은 일부구간에서 흐름정체현상과 역류현상이 발생되는데 이 구간에는 퇴적현상이 예측된다. 수리모형실험의 유사퇴적경향과 FESWMS 모형의 하상전단력을 비교한 결과는 유사하게 나타났으며, 복원하도의 넓은 둔치지역에 넓은 퇴적층이 형성되어 차후 환경구조물 등을 이용한 흐름제어 및 유지관리대책에 의한 문제해결이필요할 것으로 판단된다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.5
• /
• pp.112-119
• /
• 2007

Under normal operating condition, the conductor of overhead transmission line could be always hold it's clearance within the safety margin that is specified in the line design guide of power company. Hence it may be very important to measure/or monitor the dip of the conductor, when building a new line, re-tensioning for an aged conductor, or monitoring dynamic line rating to maximize power capability. In this paper, we suggest a new method to estimate the dip and tension by catenary angle of the conductor. Since most conductors in overhead transmission lines show typical catenary curves, it can be uniquely determined the catenary curve for the conductor from the catenary angle at tower. Based on the catenary curve, the dip or horizontal tension can be easily estimated. Through some simulation and simple experimental results, it is verified that the suggested method can be effectively applied to measure/or monitor conductor dips and tensions in the overhead transmission lines.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2012.06a
• /
• pp.78-79
• /
• 2012

To improve moving vehicles' accuracy, one-way Network RTK which guarantees high accuracy and integrity regardless the distance from rovers to Reference Station(RS) is being considered. Correction of one-way Network RTK can be generated only after constructing RS network surrounding the rover, therefore a correction discontinuity is inevitably occurred when the RS set has been changed. The discontinuity is not eliminated by the DD(Double Difference) method, and our simulation shows that it causes 13cm(horizontal) and 48cm(vertical) position error. We suggest three solutions to reduce this discontinuity, which are identification of master RS with neighbor networks, duplication of communication module to receive corrections from other network, and ambiguity levelling between neighbor networks.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.11
• /
• pp.6906-6914
• /
• 2014

This study examined the remodeling characteristics of traditional urban housing for lease focusing on Hanok in the traditional urban housing neighborhood of Bukchon. Furthermore, the space syntax was used as the main analytic approach to objectively revealing the change in social properties of each spatial element because each room forms its status in the structural relation with many rooms and accommodates the special change in traditional housing and modern life. These findings revealed the following; spatial division between the landlord and tenant results in a hierarchical change in the yard and main hall and strengthens the privacy of the space of the landlord.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.14 no.1
• /
• pp.93-105
• /
• 2012

The basic study was preceded for reducing maintenance and power cost of lighting fixture applying daylighting because most of the tunnel lighting depend on the artificial lighting. This study aims to evaluate the daylighting performance of daylighting performance of bar-type mirror reflector system in tunnel. Illuminance and luminance was measured. As a result of horizontal illuminance measurements, it was satisfied in tunnel recommended illuminance (KSA 3703) that total average was 1,170 lx increased 6.5 times more than this system was not used. Also, as a result of evaluating driver's glare on the opposite lane, glare did not occur and the luminance ratio was 3.01 which satisfies the luminance ratio standard 10.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.7 no.4
• /
• pp.185-191
• /
• 2004

A mooring system can be applied to keep the position of a floating structures. In this study, the structural analysis is carried out to analyze the dynamic characteristics of a mooring line for a floating breakwater. A three-dimensional equations of motion for a submerged chain are derived. Bending stiffness is considered for the necessary restoring force in the regions of zero tension. A fortran program is to be developed by employing finite difference method. In the algorithm, an implicit time integration and Newton-Raphson iteration are adopted. The results of simulation show good agreement in tension response pattern with the experimental results of a reference. The results of this study can contribute for the design of mooring system for a floating breakwater.

• Journal of Korean Ophthalmic Optics Society
• /
• v.5 no.1
• /
• pp.139-146
• /
• 2000

Once refractive error of the eye was fully corrected, Maddox rod was used to investigate binocular vision function. When the deviations of subjects' eyes were measured, orthophoria. without any horizontal deviations, was found in 10%, esophoria in 55% and exophoria in 34% of the patients. Esodeviation of the eye was found to be greater than exo-deviation by 11%. This is also refracted in deviations found to be greater than $4{\Delta}$ diopter magnitude where esophoria was 23% and exophoria was 9%. Thus for the patients to achieve comfortable binocular vision function, binocular vision anomalies need to be considered in spectacle prescription. In examining ocular anomalies of corrected refractive error, the deviation of the eye differed from under corrected refractive power to over corrected refractive power. There was a decrease in exophoria and an increase in esophoria, with over correction. This was thought to be due to accommodation. Furthermore, calculated AC/A ratio was found to vary from 1.25 to 6.61 and its relationship to refractive error could not be determined.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.8
• /
• pp.27-33
• /
• 2007

A novel priming discharge technique in which the ramp shaped priming pulse is superposed on the sustain period so that the entire plasma display panel (PDP) is discharged at the same time with a single drive circuit is proposed. From the experimental results, it is ascertained that the priming discharge is ignited only in a pixel in which sustain discharge does not occur and it has been understood that the priming pulse hardly influences the sustain discharge. Moreover, high-speed driving with address pulse widths of 0.7[${\mu}s$] was achieved and a wide address voltage margin of 40[V] was obtained by using the drive method applied the proposed priming discharge technique. In these results, full-HDTV PDP with 1080 horizontal scanning lines can be driven without decreasing the brightness and the possibility of the commercializing is also high because this technology is designed for using the commercialized driver IC.