• Title/Summary/Keyword: cross-channel

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Analysis of Morphological Characteristics of Farm Dams in Korea (한국 농업용 저수지의 형태학적 특성 분석)

  • Yoo, Chul-Sang;Park, Hyun-Keun
    • Journal of the Korean Geographical Society
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    • v.42 no.6
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    • pp.940-954
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    • 2007
  • This study was to analyze a total of 18,068 farm reservoirs in Korea with their basic measures, and estimate their average characteristics. These characteristics have also been compared with those of foreign countries. Histograms of seven measures(approval area, beneficial area, watershed area, effective storage, full water area, dam length, and dam height) of reservoirs are made to characterize their distributions and to apply the Pareto analysis with the power law to evaluate their inequalities. The histogram analysis shows that the measures of dam(channel cross-section) characteristics follow the log-normal distributions, on the other hand, those of the basin characteristics the exponential-type distributions. Pareto analysis was done for the five measures of having exponential distribution. The Pareto exponents estimated are 0.38 for the approval area, 0.42 for the beneficial area, -0.19 for the effective storage, 0.30 for the watershed area, and 0.22 for the full water area, so the inequality of the beneficial area is the highest and that of the effective storage is the lowest. Analysis of morphology index versus watershed area shows that most reservoirs are categorized into deep or normal ones. These characteristics are also found to be similar to those of foreign countries.

Study on Heat Transfer Characteristics of Internal Heat Exchanger for $CO_2$ Heat Pump under Heating Operating Condition (난방운전 조건하에서 $CO_2$ 열펌프용 내부 열교환기의 열전달 특성에 대한 연구)

  • Kim, Dae-Hoon;Lee, Sang-Jae;Choi, Jun-Young;Lee, Jae-Heon;Kwon, Young-Chul
    • Journal of Energy Engineering
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    • v.17 no.2
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    • pp.116-123
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    • 2008
  • In order to study the heat transfer, effectiveness and pressure drop of an internal heat exchanger (IHX) for $CO_2$, heat pump under heating condition, the experiment and numerical analysis were performed. Four kinds of IHXs were used. The section-by-section method and Hardy-Cross method were used for the numerical analysis. The effects of IHX on the flow rate of refrigerant, the IHX length, the operating condition of a gas-cooler and an evaporator and the type of IHXs were investigated. With increasing the flow rate, the heat transfer rate increased about 25%. The heat transfer of the micro-channel tube was larger about 100% than that of the coaxial tube. With increasing the IHX length, the heat transfer rate decreased. The low-side pressure drop was larger compared with that of the high-side. And the pressure drop of the microchannel tube was larger about 100% than that of the coaxial tube. With increasing the high-side temperature and decreasing the low-side temperature, the heat transfer rate increased about 3%. From this study, we can see that new correlation on $CO_2$ heat transfer characteristics and tube type is necessary.

Elastic Behavior of Zeolite Mesolite under Hydrostatic Pressure (제올라이트 메소라이트의 수압 하 탄성특성)

  • Lee, Yong-Jae;Lee, Yong-Moon;Seoung, Dong-Hoon;Jang, Young-Nam
    • Economic and Environmental Geology
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    • v.42 no.5
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    • pp.509-512
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    • 2009
  • Powder diffraction patterns of the zeolite mesolite ($Na_{5.33}Ca_{5.33}Al_{16}Si_{24}O_{80}{\cdot}21.33H_2O$), with a natrolite framework topology were measured as a function of pressure up to 5.0 GPa using a diamond-anvil cell and a $200{\mu}m$-focused monochromatic synchrotron X-ray. Under the hydrostatic conditions mediated by pore-penetrating alcohol and water mixture, the elastic behavior of mesolite is characterized by continuous volume expansion between ca. 0.5 and 1.5 GPa, which results from expansion in the ab-plane and contraction along the c-axis. Subsequent to this anomalous behavior, changes in the powder diffraction patterns suggest possible reentrant order-disorder transition. The ordered layers of sodium- and calcium-containing channels in a 1:2 ratio along the b-axis attribute to the $3b_{natrolite}$ cell below 1.5 GPa. When the volume expansion is completed above 1.5 GPa, such characteristic ordering reflections disappear and the $b_{natrolite}$ cell persists with marginal volume contraction up to ca. 2.5 GPa. Further increase in pressure leads to progressive volume contraction and appears to generate another set of superlattice reflections in the $3c_{natrolite}$ cell. This suggests that mesolite in the pressure-induced hydration state experiences order-disorder-order transition involving the motions of sodium and calcium cations either through cross-channel diffusion or within the respective channels.

A Study on Awareness and Experience of Data Publishing by Scientists (과학기술분야 연구자들의 데이터 출판경험 및 인식 연구)

  • Hyekyong Hwang;Youngim Jung;Sung-Nam Cho;Tae-Sul Seo;Jihyun Kim
    • Journal of Korean Library and Information Science Society
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    • v.54 no.1
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    • pp.45-68
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    • 2023
  • This study aims to investigate the awareness and experiences of domestic researchers regarding data publishing, which has been recognized as a new channel of data sharing as scholarly communication evolves in the open science environment. A survey is conducted among researchers from five government-funded research institutes in the field of science and technology and members of the GeoAI Data Society to confirm the awareness of data publishing. As a result of the study, domestic researchers recognized providing explanations for data, stable access to data, citation, and quality assurance through peer review as the advantages of data journals. On the contrary, a low level of recognition for data paper as one of the research outputs was presented. With regard to the properties of data publication, the respondents answered that the data description, metadata description, and permanent identifiers are highly related, however, their recognition of the relation between the properties of data publication and the data submission to a repository and data peer review was relatively low. Finally, to expand the data publication, the need for the development of an editorial system that supports data paper peer review and cross-linking to a data repository as well as the development of a repository that supports data citation was identified. This study on the domestic researchers' experience and awareness of data publishing can provide insights for the implementation of data publishing services and infrastructure in the future.

Current Structure and Variability in Gwangyang Bay in Spring 2006 (2006년 봄철 광양만 해류의 구조와 변동)

  • Lee, Jae-Chul;Kim, Jeong-Chang
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.12 no.3
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    • pp.219-224
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    • 2007
  • Two monitoring buoys equipped with ADCP were deployed at the deepest positions along the trough of the central Gwangyang Bay in spring 2006 in order to study the circulation in the bay. Northward velocity is commonly dominant at both stations located in the eastern part of the channel, which supports the cyclonic circulation accompanied by the southward flow in the western part. The southern station has a distinct two-layer structure with current reversal at 14 m depth and increasing northward velocity in the lower layer to 36 m depth close to the bottom. At the northern station the northward flow becomes accelerated due to the decrease in the cross-sectional area and this northward current is dominant even in the upper layer. In the modal structure from the EOF analysis, the first mode has 74% of total variance at the northern station whereas it is 67% but the baroclinic portion increases at the southern station. The typical northward velocity is about 10 cm/s which is associated with the cyclonic circulation. Subtidal variability due to the local wind effect is negligible, but the nonlocal response associated with offshore Ekman flux by the zonal wind is found during strong wind events.

Economic Rationale of Compensating Balance Requirements and Its Impact on Money Supply (「꺾기」의 경제학(經濟學)과 통화량(通貨量) 효과분석(效果分析))

  • Jwa, Sung-hee
    • KDI Journal of Economic Policy
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    • v.14 no.1
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    • pp.89-119
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    • 1992
  • This paper purports to analyze the economic rationale of compensating balance requirements and its impact on money supply. This practice has recently been severely criticized for artificially increasing the money supply and, therefore, limiting the nation's aggregate lending policy under the tight constraint of the given money supply target. A review of the existing literature implies that compensating balance requirements is a banking practice which leads to corrections in the distortion of financial resource allocation due to the imperfection of financial market stemming from asymmetric information and/or financial regulations on deposit and lending rates. Therefore, the economic rationale of this practice is deemed to improve the efficiency of financial resource allocation. On the other hand, the macroeconomic impact of compensating balance requirements on the money supply depends on the impact on the money multiplier, which in turn depends on the desired ratio of deposit that people wish to maintain on the money borrowed from the banking system, and on the desired reserve ratio that the banking system would like to hold for deposit withdrawal. If the compensating balance requirements could increase the desired ratio of deposit to borrowing (bank lending), it will increase the available amount of total reserve within the banking system and, in turn, the money multiplier. However, this channel has not been fully analyzed in the literature, and the direction of the effect is ambiguous. If the practice could reduce the turn-over rate of deposit and, thereby, reduce the desired reserve ratio of the banking system, then it will also increase the money multiplier. While this channel operates unambiguously toward increasing the money multiplier, this effect will be limited by the extent that the banking system holds the excess reserve over the required reserve because the excess reserve will set the maximum amount for the desired reserve to fall. This paper tries to determine the effect on the money supply by empirically estimating the multiplier and the desired ratio of deposit to lending equations as functions of the ratio of compensating balance to the related lending, which is not observable and is estimated for the regression purpose. The results suggest that the effect of compensating balance requirements on the money supply in Korea does not exist or is very tenuous even if it could operate. Therefore, this paper concludes that the well publicized policy of cross cancelling the compensating balance and the related lending will not be effective at controlling the money supply and increasing the amount of loans without expanding the money supply.

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Accuracy evaluation of microwave water surface current meter for measurement angles in middle flow condition (전자파표면유속계의 측정 각도에 따른 평수기 유속 측정 정확도 분석)

  • Son, Geunsoo;Kim, Dongsu;Kim, Kyungdong;Kim, Jongmin
    • Journal of Korea Water Resources Association
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    • v.53 no.1
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    • pp.15-27
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    • 2020
  • Streamflow discharge as a fundamental riverine quantity plays a crucial role in water resources management, thereby requiring accurate in-situ measurement. Recent advances in instrumentations for the streamflow discharge measurement has complemented or substituted classical devices and methods. Among various potential methods, surface current meter using microwave has increasingly begun to be applied not only for flood but also normal flow discharge measurement, remotely and safely enabling practitioners to measure flow velocity postulating indirect contact. With minimized field preparedness, this method facilitated and eased flood discharge measurement in the difficult in-situ conditions such as extreme flood in active ways emitting 24.125 GHz microwave without relying on natural lights. In South Korea, a rectangular shaped instrument named with Microwave Water Surface Current Meter (MWSCM) has been developed and commercially released around 2010, in which domestic agencies charging on streamflow observation shed lights on this approach regarding it as a potential substitute. Considering this brand-new device highlighted for efficient flow measurement, however, there has been few noticeable efforts in systematic and comprehensive evaluation of its performance in various measurement and riverine conditions that lead to lack in imminent and widely spreading usages in practices. This study attempted to evaluate the MWSCM in terms of instrumen's monitoring configuration particularly regarding tilt and yaw angle. In the middle of pointing the measurement spot in a given cross-section, the observation campaign inevitably poses accuracy issues related with different tilt and yaw angles of the instrument, which can be a conventionally major source of errors for this type of instrument. Focusing on the perspective of instrument configuration, the instrument was tested in a controlled outdoor river channel located in KICT River Experiment Center with a fixed flow condition of around 1 m/s flow speed with steady flow supply, 6 m of channel width, and less than 1 m of shallow flow depth, where the detailed velocity measurements with SonTek micro-ADV was used for validation. As results, less than 15 degree in tilting angle generated much higher deviation, and higher yawing angle proportionally increased coefficient of variance. Yaw angles affected accuracy in terms of measurement area.

Development and Research for the Professional Brand of TV Broadcasting Program -By focusing the actually proved study for news program brand- (TV 방송 프로그램의 전문 브랜드 개발 연구 -뉴스 프로그램 브랜드의 실증연구를 중심으로-)

  • Jeong, Bong-Keum;Chang, Dong-Ryun
    • Archives of design research
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    • v.18 no.1 s.59
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    • pp.39-48
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    • 2005
  • In the age of digital culture, TV broadcasting is exercising more influence as a information and communication medium compared to past. With the appearance of satellite broadcasting service in 2002, the broadcasting environment became a diversified field of local TV, cable TV, satellite, internet, etc. and created the time of multi-media and multi-channel. This ongoing change of broadcasting environment made the passive audience of the past, active image makers and new accepters, participants and users of communications, who know how to choose and use media as the active centerpiece, The active acceptor as the centerpiece of channel selections has become the center of the broadcasting, whereby they pick up and enjoy their favorite TV programs and came to remember the list of their favorite channels and zap them finally. In this point of spotting their favorite channels and improving the degree of recognition for the channels, the development of the noticeable brand for a particular program has made a great contribution. The aim of this study, therefore, is to recognize the factors, which are important in the habits of watching TV and to develop professional brands for TV broadcasting programs. The range of the survey for this study was home news programs and broadcasting stations abroad, which were on air from March to May in 2004. The focus of the survey was universal and professional news programs. Through this study, it was ascertained that, in the case of news, developing a brand for an anchor as well as for a professional brand of TV program could be an important element.

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Independent Production Routines and Environmental Changes In 'Comprehensive Programming Television Channels' in Korea Focusing on Interviews with Independent Producers, Broadcast Writers and Individuals Involved with the TV Channels (종합편성채널의 독립제작 환경과 관행에 관한 연구 독립PD, 작가 및 종합편성채널 관계자 심층인터뷰를 중심으로)

  • Choi, Sun Young;Han, Hee Jeong
    • Korean journal of communication and information
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    • v.73
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    • pp.56-91
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    • 2015
  • This study examined changes in the independent production environment in the perspectives from flexible specialization of labor and media routines since January 2011, when comprehensive programming television channels (JTBC, MBN, Channel A, TV Chosun) emerged in Korea. In-depth interviews were conducted with thirteen individuals, including producers from independent production companies, broadcast writers, and individuals involved with these TV channels. The interview results indicated that a flexible specialization production system had been established by the comprehensive programming channels. This means that they were heavily dependent on independent producers, except in relations to their own news programs. Moreover, it was identified that the production of diverse programs could be difficult due to absurd contract practices such as those related to TV ratings and performance systems. Second, these channels have implemented some positive changes such as the payment of higher production costs and an incentive system, compared to terrestrial TV stations. However, the incentive system also helps to aggravate internal competition in the channel and also instigate contract competitions among independent companies, which can eventually result in the channels for holding exclusive rights to certain content and, hence, unfair business practices. Third, as a result of the newspaper and broadcast cross-owenership system of the comprehensive programming channels, hierarchical independent production practices can be established under the influence of newspaper proprietors and executives or managers who have previously worked for newspapers. Lastly, as a result of interviews with independent producers and individuals involved with the TV channels concerning the awareness of comprehensive programming channels, it could not be ascertained whether it is difficult to produce programs dealing with diverse items and genres, because programming autonomy has been distorted by capital or the advertisement market. In this circumstance, it is not surprising that some comprehensive programming channels mentioned that they prioritize profit and performance in programming. In conclusion, it is absolutely imperative that complementary and legal measures be implemented institutionally in order to redress the existing systematic dysfunctional routines in the independent productions of the comprehensive programming TV channels in Korea.

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Characteristics of Channelbed and Woody Debris on Mountainous Stream (산지급류소하천(山地急流小河川)에 있어서 하상미지형(河床微地形)과 유목(流木) 특성(特性))

  • Chun, Kun-Woo;Kim, Min-Sik;Park, Wan-Geun;Ezaki, Tsugio
    • Journal of Korean Society of Forest Science
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    • v.86 no.1
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    • pp.69-79
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    • 1997
  • The purpose of this study is to acquire essential data to reduce the amount of woody debris resulted from the debris flow. This research examined topographic characteristics of the channelbed affecting generation, movement and storage of woody debris and woody characteristics related to number, sizes, shapes, decay, storage direction to mountainous stream. 1. The number of woody debris had a tendency to increase in proportion to stream width, but it was hardly affected by longitudinal gradient of stream. Especially, the greater amount of woody debris was stored at wide section of the stream with compound channel, and it was found in deposits of channelbed rather than in the present channel. 2. Total woody debris over 10cm in diameter and over 2m in length was 402 units and storage number was 35.3 units per 100m of stream. Average diameter of breast height and length were 14cm and 4m, respectively. The woody debris appeared shorter in length and greater in diameter at down-stream than up-stream. 3. Since woody debris met sediments and bed-materials of great roughness in moving, the greater amount of woody debris without root was found in up-stream and down-stream, but deformed woody debris was discovered in upper stream. Decay of woody debris was more severe in down-stream and woody debris on rotting process was found down-stream. 4. Storage direction of woody debris was mainly parallel to center line of stream, and rate of parallel and perpendicularity was 276 and 126 units, respectively. But, as woody debris storing to the perpendicular direction was unstable, the traveling debris could easily be stored. Therefore, some counterplan was required to prevent the traveling woody debris. 5. Tree species of woody debris was mainly larch, which occupied about two third of total woody debris(256 units). The woody debris of larch is easy to move due to hitting of channelbed materials or lower channelbed fluctuation because the lower part of larch is weaker than its upper part. Therefore, the section of the tree species planting in the riparian vegetation needs much more carefulness.

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