• Journal of Korea Water Resources Association
• /
• v.49 no.10
• /
• pp.887-901
• /
• 2016

Cohesive sediments form flocs through the flocculation process. The size and density of floc are variable whereas those of a fine sediment are always assumed to be constant. The settling velocity, one of main factors of sediment transport, is determined by size and density of particle. Therefore, the flocculation process plays an important role in transport of cohesive sediment. It is of great difficulty to directly measure the density of floc in the field due to technical limitation at present. It is a popular approach to estimate the density of floc by applying the fractal theory. The main assumption of fractal theory is the self-similarity. This study aims to examine the applicability of fractal theory to cohesive sediment in small rivers of Korea. Sampling sediment has been conducted in two different basins of Geum river and Yeongsan river. The results of settling experiments using commercial camera show that the sediment in Geum river basin follows the main concept of fractal theory whereas the sediment in Yeongsan river basin does not have a clear relationship between floc size and fractal dimension. It is known from this finding that the fractal theory is not easily applicable under the condition that the cohesive sediment includes the high content of organic matter.

• Journal of Korean Society of Transportation
• /
• v.21 no.4
• /
• pp.67-77
• /
• 2003

The purpose of this study is to provide the criteria for implementing unprotected left turn at intersections with variation of traffic volume on a cross road approach. Using Transyt-7F model, the delays calculated from permissive and protected left turn signal system were compared by gradually increasing the left turn volume for a certain opposing through volume up to the volume limits to which permissive left turn is more effective, Average stopped delay of the intersection was used as the measure of effectiveness in this study. The major conclusions are (1) the lighter the traffic gets in a cross road, the more the allowable left turn volume increases. The allowable left turn volume when the ratio of cross traffic to the concerned approach traffic is 0.6 appears about 50% more than the volume when the ratio is 1.0. (2) Comparing to the criteria of the manual of traffic safety facility, the results when the traffic ratio is 0.6 seem to be most similar the criteria of manual and the results when the traffic ratio are 0.8 and 1.0 appears to be lower than the criteria of manual. (3) The possible amount of making a left turn that is inversely proportional to the opposing through traffic, decreases as the number of opposing through lanes increases. The products of volume need to be used as the criteria of permissive left turn with considerable cautions because of its low consistency.

• Journal of the Korean Society of Radiology
• /
• v.7 no.4
• /
• pp.307-311
• /
• 2013

This study examined the change of artifact volume by analyzing the level of image change associated with the setting of threshold through 3D imaging in scan parameter(slice thickness and helical pitch) and 3D image reconstruction to explore whether the presence of pathology was fully distinguished when CT was taken by lower dose than the existent dose to reduce exposure. Furthermore, this study attempted to investigate Scan Parameter acceptable in CT to reduce exposure dose. For materials and methods, silicon was used to produce samples. Five spherical samples were produced at 10-millimeter intervals(50, 40, 30, 20, and 10 mm) in diameter and were fixed at 120 Kvp of tube voltage and 50 mA of tube current. Varied slab thickness((1.0, 2.0, 3.0, 5.0, and 7.0mm) and Helical Pitch(1.5, 2.0, 3.0) were scanned. The image at an interval of 1.0, 2.0, 3.0, 5.0, and 7.0mm was transmitted to the workstation. Threshold(-200, -50, 50 ~ 1,000) was changed using the volume rendering technique, 3D image was reconstructed, and artifact volume was measured. In conclusion, 1.5 of Helical Pitch showed the least change of volume and 3.0 of helical pitch showed the greatest reduction of volume change. The experiment suggested that as slice thickness was increased, artifact volume was decreased more than actual measurement. Furthermore, in the 3D image reconstruction, when the range of threshold was set as -200 ~1,000, artifact volume was changed the least. Based on the results, it is expected to have an effect of reducing exposure dose.

• Korean Journal of Environmental Biology
• /
• v.35 no.4
• /
• pp.640-647
• /
• 2017

The need for an efficient sampling technique to collect aquatic organisms has risen with the increase of interest in rice paddy fields, which have been recognized as important ecosystems supporting biodiversity. In the present study, a submerged funnel trap used with the assistance of attracting agents (fish meal and chemical light) was designed as an easy, objective and quantitative tool for collecting aquatic organisms in the rice paddy fields. The preference for collecting aquatic organisms as a means for attracting agents was analyzed using a generalized linear mixed model. Also, based on the data of previous research, we compared the community composition of the aquatic macroinvertebrates, which were collected using the quadrat method, and newly designed submerged funnel traps, by analyzing non-metric multidimensional scaling. The results showed that the catching efficiency of 18 of the total 65 taxa was affected by the attracting agents. 12 taxa including Pomacea canaliculata, Hippeutis cantori, Austropeplea ollula, Erpobdella lineata, Ostracoda spp. Branchinella kugenumaensis, Hydaticus grammicus, Rhantus pulverosus, Chironomidae spp., Rana nigromaculata, Cobitidae spp. etc., favored fish meal and 6 taxa including Ischnura asiatica, Coenagrionidae spp. Sternolophus rufipes etc., were attracted by chemical light. The submerged funnel trap used as a measurement tool for biodiversity was less applicable than the quadrat method; however, it was more effective for the selective collection of specific taxa. We expect that this newly designed trap can be a simple and quantitative method for collecting aquatic organisms, and could be used for long term and extensive surveys in rice paddy fields in the future.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.9
• /
• pp.543-551
• /
• 2016

Recently, the cultural industry has become an attractive industry which is having a dramatic effect with the rise of Hallyu offering many possibilities for development. Specially, the marketing techniques employed by the performing arts industry started to change to respond to consumer tastes and demands like other commodity markets, as the popular performing arts industry began to receive attention as a promising industry. It is important to identify the behavior of consumers in order to actively deal with the demands and tastes of consumers that are becoming increasingly diverse and individualized. The performing arts market needs to recognize the importance of its audience and to apply appropriate marketing techniques. This study attempted to empirically identify the value of performing arts perceived by the audience and to investigate the influence of the relationship between the perceived value, attitude formation and satisfaction with performing arts. In order to examine the influence of the value of performing arts on attitude and customer satisfaction, a reliability analysis and factor analysis were conducted to investigate the dependability and validity of the measured variables. In order to achieve the study's intended purpose, the structural equation model (SEM) was utilized as the core analysis method. As a result, it was found that the perceived value and attitude towards performing arts have a positive effect on customer satisfaction. The results of this study are expected to be used as the basic data for organizations that plan performances to improve their marketing and promotion around the audience and for more specific and detailed research in the future.

• Journal of Advanced Navigation Technology
• /
• v.14 no.6
• /
• pp.890-899
• /
• 2010

The sport industry has been continuing to grow in the past few decades in the U.S., and it presents significant opportunities for the practitioners to increase the number of patrons. To convert this opportunity to optimum benefits for a sport organization, one of the most significant challenges for the practitioners would be promoting sport attendance and repatronage. So far, many studies have tried to identify variables that affect the level of sports attendance. However, many of these variables are rather uncontrollable due to the nature of the sports and contingencies that are derived from many areas of uncertainties. Thus, to acquire competitive advantage and profit maximization, it would be essential for the managers to focus on understanding controllable elements. This study found that many controllable variables that influence sports attendance coincide with the servicescape elements which have been widely used in the hospitality industry since 1992. In the light of the conceptual framework of servicescape, this study also attempted to isolate the controllable variables that can be utilized to increase the sports attendance. This study presents its significance not only in extending the application of servicescape concept to the sport industry, but also in providing suggestions for future empirical studies that would further identify these variables, gauge the relationship between those variables, and assess its impact on the sports attendance.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.203-203
• /
• 2019

도시화로 인한 불투수면의 증가는 물순환 왜곡, 비점오염원 발생 및 수생태계 건상성 훼손 등을 야기시키며, 이를 해결하기 위하여 다양한 LID 기법을 적용하고 있다. 일반적으로 LID 내 적용 되는 여재들은 무기성여재로 중량이 크고 미세공극의 부재로 물리화학적 및 생물학적 저감기능이 제한적이다. 따라서 본 연구에서는 중량성이 낮은 생물폐자원을 선정하여 LID 시설 적용성평가를 수행하고자 한다. 생물폐자원은 발생량, 경량성 및 용이성을 고려하여 꼬막껍질(CS)과 호두껍질(WS)을 선정하였다. 생물폐자원의 산화부식을 고려하여 무기성 여재인 화산석과 혼합하여 Bioretention 시설에 적용하였으며, 여재 혼합비율에 따라 총 3가지의 Case 로 구성하였다. 식생은 구절초와 꽃댕강나무를 식재하였으며, 여재의 물리적 특성 분석을 위하여 적용 전과 후의 SEM(Scanning Electronic Microscope)을 수행하였다. 모니터링은 도로퇴적물 100g과 물 110L를 제조하여 인공강우유출수를 이용하여 수행하였으며, $0.0003{\sim}0.007m^3/sec$의 유속으로 주입하였다. 시설의 유입 및 유출부에서 유량 측정 및 수질 시료를 채취하였으며, 채취된 시료는 수질오염공정 시험법에 준하여 입자상 물질, 유기물, 영양물질 및 중금속 등을 분석하였다. Bioretention 시설의 모니터링 결과를 이용하여 물수지 및 TSS 저감 효율을 산정하였으며. 물수지 분석결과 시설의 저류율은 Case 1(soil) > Case 3(WS+RV) > Case 2(CS+RV) 순으로 나타났다. 시설 내 공극률이 가장 낮았던 Case 1에서 저류율이 약 55%로 가장 높게 것으로 분석되었다. Case 3(WS+RV)은 Case 2(WS+RV)와 시설 내 공극률이 유사함에도 불구하고 저류율이 약 10% 높은 것으로 분석되었다. 오염물질 저감효율 분석 결과, TSS와 TP의 제거효율은 모든 Case에서 약 75% 이상으로 높게 나타났으며, COD의 경우 모래를 적용한 Case 1에 비해 생물폐자원인 꼬막껍질과 호두껍질을 적용한 Case에서 약 1.3배 이상 높게 나타났다. 호두껍질과 꼬막껍질의 SEM 분석 결과 표면에 다공성이 형성되어 있는 것으로 조사되었다. 이는 여과 및 저류기작으로 인한 물순환 효과증대와 다공성과 돌기사이로 인한 입자상의 물질 여과 및 흡착으로 인하여 오염물질의 제거효율이 증대 된 것으로 평가된다. LID시설 내 생물폐자원과 무기성여재를 적절히 배합하여 복합여재로 조성할 경우 침하현상을 방지할 뿐만 아니라 저류 및 침투기능 향상과 미생물의 서식환경을 제공하기에 물순환 회복 및 비점오염물질 저감에 기여할 것으로 평가된다.

• 한국사회정책
• /
• v.25 no.4
• /
• pp.71-104
• /
• 2018

This paper adopts a distributive performance process model of in-work poverty based on labor markets, households, and welfare states and analyzes the 4-11 waves of the Korean Welfare Panel Study during 2008-15. Previous studies on in-work poverty have focused on the definitions and concepts of in-work poverty by analyzing employment and unemployment persistence and repetition dynamics, but rarely paid attention to institutional distributive performance. In this regard, this study preforms a stepwise analysis of labor markets, households, and welfare states as a process of income generation in labor markets, satisfaction of welfare needs and income pooling at households, and deduction of social security contribution and income tax as well as receipt of public transfer income at welfare states. Results of empirical analysis show that in-work poverty had been on increase during 2008-11, followed by a decrease between 2012-15. At labor market stages, full time status had the most prominent impact on in-work poverty process, while status by employment and contract type have generated a huge variation as well. At household stages, household work intensity and number of earners contributed to reduction of in-work poverty, but the relations did not seen to be straightforward. However, welfare state played little role in lifting employees out of in-work poverty. In terms of institutional distributive process, in-work poverty was prevalent in either household-welfare state stage or labor market-household-welfare stage. Non-vulnerable group in terms of in-risk poverty was around 80% of the sample during the period of analysis, the size of which has remained constant.

• International Area Studies Review
• /
• v.15 no.3
• /
• pp.263-283
• /
• 2011

As China has achieved continuous high growth, innovative housing system and rapid growth of housing finance for thirty years since its reforming and opening, Chinese real estate industry has developed rapidly, investment in real estate has increased remarkably and price of real estate has increased continuously. In particular, as China joined WTO in 2001, overseas companies have expanded investment in Chinese real estate market with chances of potential profit. Recently, management of foreign capital real estate companies has expanded from housing to office buildings and luxury shops. Besides, management has expanded from real estate development to various tasks such as management, brokerage service, lease management and financial investment. In order to measure relationship between FDI in Chinese real estate and Chinese housing price, this document utilizes not only various data such as housing price, FDI to real estate, domestic loan of real estate, interest rate and exchange rate in 35 major cities across China but also previous researches to set an empirical analysis model and analyze effects of foreigners' direct investment in Chinese real estate on Chinese housing price.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.2
• /
• pp.190-199
• /
• 2019

This study was conducted to expand the distribution of new technology efficiently by analyzing the structure relationship based on the innovation resistance model and partial least square structural equation model (PLS-SEM). This study selected innovative propensity, relative advantage, compatibility, complexity, trialability, risk, and extension service consisting of educational, technical, and funding services as factors affecting innovation resistance. This study constructed a questionnaire that measured 11 factors including acceptance intention of new technology using 33 indicators. Data was from April to October, 2017, targeting 180 farmers who did not join in projects to spread new technologies of the Rural Development Administration. Results showed the factors positively and significantly affecting innovation resistance include complexity and risk. Innovative propensity did not have any effect on innovation resistance. However, it positively affected acceptance intention of new technology. The service of the extension organizations had a negative effect on innovation resistance, but did not affect acceptance intention of new technology. This study suggests that extension services should promote activities such as education, consulting, publicity and pilot projects related with new technologies in order to minimize the antipathy toward new agricultural technologies.