• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.2
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• pp.422-429
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• 1990

The experimental study investigates two aspects of counterflow sensible heat regenerator operation. First, it examines the regenerator performance in periodic steady state operation with spatially nonuniform inlet temperature in one of the fluid stream. Second, the study examines the transient response of a regenerator to a step change in the inlet temperature of one of the fluid streams. The effect of transient inlet temperatures is analyzed in terms of the response of the outlet fluid temperatures to a step change in temperature of one of the inlet fluid streams. The effect of temperature nonuniformities is analyzed in terms of the change of temperature nonuniformities is analyzed in terms of the change in steady state effectiveness due to a circumferential temperature distribution in one of the inlet fluid streams. an experimental analysis has been conducted using a counterflow, parallel passage, and rotary regenerator made from polyethylene film. Efficiencies follow similar trends with increasing matrix to fluid capacity rate ratio for the balanced and symmetric regenerator with nonuniform inlet temperature.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.4
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• pp.573-584
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• 2006

This study was carried out to investigate the causes of fish kills in the Yudeung Stream in Daejeon, Korea using literature reviews, governmental and our water quality monitoring data of the study site, rainfall data, intensive water quality monitoring during rainfall events, sediment pollutant contents and laboratory bioassay tests. Fish kill in urban streams can be caused by combined effect of reduction in dissolved oxygen concentration, increase in toxic material or increase in turbidity in waterbody due to introduction of surface runoff or effluent of combined sewer overflows after rainfall from the watershed areas. Despite of extensive and intensive field surveys and laboratory tests, it was found that those conventional methods have limitations to identify causes of fish kills in urban streams. It would be necessary to use dynamic water quality modeling to predetermine the range and level of water pollution in the stream and automatic water quality monitoring system that can collect water samples and detect water quality continuously.

• Journal of Korean Society on Water Environment
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• v.29 no.1
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• pp.36-44
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• 2013

HSPF model based on BASINS was applied to analyze effects of watershed management measures for water quality conservation in the Hwaseong Reservoir watershed. The model was calibrated against the field measurements of meteorological data, streamflow and water qualities ($BOD_5$, T-N, T-P) at each observatory for 4 years (2007-2010). The water quality characteristics of inflow streams were evaluated. The 4 scenarios for the water quality improvement were applied to inflow streams and critical area from water pollution based on previous researches. The reduction efficiency of point and non-point sources in inflow streams was evaluated with each scenario. The results demonstrate that the expansion of advanced treatment system within wastewater treatment plants (WWTPs) and construction of pond-wetlands would be great effective management measures. In order to satisfactory the target water quality of reservoir, the measures which can control both point source and non-point source pollutants should be implemented in the watershed.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.68-73
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• 2005

The purpose of this study are to insure flow rate for rural stream in the rural area. The analysis of drying stream characteristics for two streams(Bong-mu, Wang-jang stream) from field survey data. Also, a study area has been determined, and criteria of estimation has been established : criteria such as, available hydrological data, the size of stream lengths and basin areas and regional characteristics. The spacial analysis is applied to stream slopes for upstream and downstream at weirs, stream networks and ground water pump stations, sinuosity of drying stream. As a result of drying streams survey analysis, drying stream characteristics are followed; levee types are earth and natural, cross sectional shapes are trapezoid, stream bed materials are gravels and sands, facilities in streams are weirs. The cause of the reduction analyzed by investigation of the current status of facilities for agricultural water use. Agricultural reservoirs block up the stream and water does not flow over the reservoirs except by storm. They also discharge water through diversion channels and the water diverted does not flow through the natural stream. Farmers directly take water from the stream by weirs.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.265-270
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• 2006

The nucleotide sequence variations of mitochondrial DNA were investigated to understand genetic differentiation for five different Pungitius kaibarae populations at five study sites from selected four streams flowing into the East Sea. The complete sequences of mtDNA control regions of them were determined the constant sites 342 bp and variable sites 183 bp including parsimony infromative sites 122 bp. Based on the phylogenetic tree, five populations were monophyletic unit (97% MPand 100% NJ) and separated two groups (Myongpa-Songhuen stream group and others group). The population of Baebong stream (82nd bp, G-A) consistently formed them of the Jasan stream into a monophyletic unit even though it is closer then Myongpa stream (99th bp, T-C) from the Baebong stream. Further studies on the molecular phylogeny for the primary freshwater fish are needed to establish for the fish biodiversity conservation in mountainous and upland streams.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.4
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• pp.39-48
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• 2004

In the 1960s, polluted urban streams were covered and paved in concrete. Rivers became sewers buried under road. As a result, wildlife habitat was lost and the open stream space was gone. In the 1990s, there was a movement for restoring urban streams to enhance the quality of life of inhabitants. Chungkye Stream, whose covering began from early 1950s and ended in 1977, is now in the process of restoration together with the Central Business District (CBD) Redevelopment Plan. However, as the construction proceeds, several problems were raised, and serious controversies resulted. Therefore, this study aims to investigate the validity of the approach of the Chungkye Stream Restoration Project through a literature survey and a site survey, and to present the improved alternative. Ultimately, the study aims to contribute to present references or guidelines for similar urban stream restoration projects. The Chungkye Stream Restoration Project has some of the following problems. First, the construction should be done based on the long-term urban redevelopment plan. Second, the construction period should be extended to restore urban streams. Third, the cultural asset conservation plan should be implemented. In order to fulfill the anticipated purpose, the above mentioned problems need to be solved.

• Korean Journal of Environment and Ecology
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• v.29 no.2
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• pp.210-220
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• 2015

We quantified temporal and spatial changes in the habitat for fish populations, the distribution of mandarin fish(Siniperca scherzeri) and an introduced species, largemouth bass(Micropterus salmoides) in Lake Paro and inflowing streams. The number of fish species identified in Lake Paro and the tributary streams included 10 families, 24 species and 10 families 30 species, respectively. The dominant fish species in Lake Paro were Zacco platypus, Hemibarbus labeo, Squalidus gracilis majimae, S. scherzeri and Tridentiger brevispinis, Z. platypus, Z. koreanus, and S. gracilis majimae in the inflowing streams. Although the habitat segregation for S. scherzeri and M. salmoides occurs, these two species showed the use of the fishes of the family Gobiidae as an important prey item based on IRI analysis. S. scherzeri and M. salmoides preyed mainly on T. brevispinis(67.4 %) and R. brunneus(84.0 %), respectively. The species preyed on by S. scherzeri and M. salmoides were benthic fishes that inhabit shallow water depths around the lake and have little swimming ability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1554-1559
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• 2000

On ATM networks, MPEG video stream is transferred using CBR or VBR services. But because the MPEG video traffic varies greatly from time to time, it is very difficult to transfer the MPEG steam efficiently without loss of transmission bandwidth. Until now, the study on the traffic analysis and control on a single MPEG video stream has been done by many researchers, but the traffic analysis and control on a multiplexed traffic of multiple MPEG video streams has not been studied by any researcher. This paper proposes a multiplexing method to reduce the PCR and traffic variance of a multiplexed traffic of multiple MPEG video streams. By reducing the PCR of the multiplexed traffic, the multiplexed VBR traffic can be transferred efficiently with less loss of transmission bandwidth.

• Journal of Broadcast Engineering
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• v.5 no.2
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• pp.176-187
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• 2000

MPEG-4 is a digital bit stream format and associated protocols for representing multimedia content consisting of natural and synthetic audio, video and object data. This paper describes an application where multiple audio/visual data stream are combined in MPEG-4 and transported via MPTG-2 transport streams(TS). Also, this paper describes how to convert MPEG-4 Over MPEG-2 TS bit streams into MP4 file which Is designed to contain the media information of an MPEG-4 presentation in a flexible, extensible format. MPEG-4 is presented in the form of audio-visual objects that are arranged into an audio-visual scene by means of a scene descriptor and is composed of the audio-visual objects by means of an object descriptor. These descriptor streams are not defined MPEG-2 TS. So. this paper focuses on handling of these descriptors and parsing TS streams to get MPEG-4 data. The MPEG-4 Over MPEG-2 TS to MP4 format converter is implemented in the demonstrated systems.

• Health Policy and Management
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• v.30 no.3
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• pp.286-300
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• 2020

In 2019, the Seoul metropolitan government established its own 'Seoul-type paid sick leave project'. Although the central government had to introduce such a system, which is also called sickness benefits, it was not implemented. In order to understand the process by which the Seoul government has implemented such a policy, this study used Kingdon's multiple streams framework. As a result, in the problem stream, it was found that the economic burden of sickness has been considered only in terms of medical expenses in the past of Korea. Then Songpa's three women and Middle East respiratory syndrome incidents raised awareness of the necessity of the sickness benefit system in 2014 and 2015. In the political stream, several social affairs such as national health insurance huge surpluses and the 2017 presidential election opened policy window. At that time, Seoul Mayor actively promoted sickness benefits as a policy entrepreneur. In the policy stream, the sickness benefit system has gained new attention through political events. To summary, these three streams flowed separately and then they assembled around huge political affairs. As a result, it was confirmed that Kingdon's model is the most effective theory than any other models in analyzing the health care policy decision process in Korea.