• Journal of the Korean Data and Information Science Society
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• 제18권3호
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• pp.609-617
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• 2007

The goal of this study is to forecast the trend of stream quality and to suggest some policy alternatives in Gumbo river. It used the five different monthly time series data such as BOD, COD, T-N and EC of the nine of Gumbo River measurement points from Jan. 1998 to Dec. 2006. Water pollution is serious at Gumbo2 and Palgeo stream measurement points. BOD, COD, T-N and EC data are analyzed with the exponential smoothing model and the trend is forecasted until Dec. 2009.

• 한국약용작물학회지
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• 제19권6호
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• pp.407-413
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• 2011

This study was analyzed and investigated to evaluate ecological distribution of medicinal plants in Miho Stream of Korea. Totality 463 taxa of vascular plants were appeared in lower part of Miho Stream. Medicinal plants were distributed 253 taxa, which were 54.6% of the total vascular plants appeared. Medicinal plants of official drug compendium(Korean pharmacopoeia) were 85 taxa. Medicinal plants were distributed most of the forest area, and followed field surrounding, stream surrounding and paddy surrounding respectively. The distribution of life form hemicryptophyte was the most frequent. Plant community of appearing area of medicinal plants was classified into Salix koreensis, Phragmites japonica, Echinochloa crusgalli, Artemisia selengensis, Miscanthus sacchariflorus, Setaria faberii, Panicum dichotomiflorum, Bidens frondosa, Humulus japonicus, Monochoria vaginalis var. plantaginea, Eleocharis kuroguwai, Erigeron acris, Pinus densiflora, Pinus rigida, Quercus acutissima, Quercus serrata, Robinia pseudoacacia and Castanea crenata community. Medicinal plants in plant communities that occur frequently were Humulus japonicus, Corylus heterophylla and Liriope spicata.

• 한국정보통신학회논문지
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• 제9권1호
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• pp.76-87
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• 2005

본 논문에서는 무선을 포함한 패킷 전송에서의 효율성을 위해 차세대 전송 계층 프로토콜인 SCTP에 ROHC(RObust Header Compression)을 적용한 ROHC 프로파인 7(ROHC-SCTP)을 제안한다. 제안된 ROHC-SCTP는 SNR(Sequence Number ROHC)-SCTP의 1 또는 2 바이트 길이의 새로운 필드를 SCTP 패킷 헤더에 추가하여, SCTP 멀티 스트림을 acknowledgement 스트림과 data 스트림으로 나누어 헤더 압축을 하며, 동기화 손실이 발생한 경우 context를 복구하는데 사용될 수 있도록 설계되었다. ROHC-SCTP의 제안을 통해 SCTP 헤더의 오버헤드 율을 최대 25%까지 감소할 수 있으며 대역폭 또한 최대 5% 정도 절약할 수 있다.

• 자원리싸이클링
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• 제20권5호
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• pp.3-15
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• 2011

이 논문은 1960년부터 2009년까지의 미국의 생활쓰레기 재활용과 관련된 자료를 종합하여 정리한 것이다. 이 논문에서 언급되는 자료들은 주로 물질수지를 통하여 물질흐름을 파악하는 방법으로 다루어 졌기 때문에 어느 한 지역이 아닌 전국 단위의 MSW 흐름을 이해하는데 도움이 될 것으로 생각한다. 생활쓰레기에 포함된 수많은 물질들 중에서 그 발생량이 많은 종이와 판지, 유리, 금속류, 폐플라스틱, 음식물쓰레기, 정원손질쓰레기의 발생과 재활용 현황을 보다 자세히 다루었다.

• 한국관개배수논문집
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• 제18권2호
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• pp.3-14
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• 2011

Increased impervious surfaces alter stream hydrology resulting in lower flows during droughts and higher peak flows during floods. Not only urban area but also rural area has been expanded impervious surfaces because of increasing of greenhouses. The main objective of this study was to evaluate the performance of the AnnAGNPS (Annualized Non-Point Source Pollution Model) on the surface runoff characteristics of the Daejeon-Stream watershed, and to predict the hydrological effects due to increasing of impervious surfaces. The model parameters were obtained from the geographical information system (GIS) databases, and additional parameters calibrated with the observed data. The model was calibrated by using 2004 of the runoff data and validated by using 2002 data obtained from WAMIS (Water Management Information System) to compare the simulated results for the study watershed. R2 values and efficiency index (EI) between observed and simulated runoff were 0.78 and 0.80, respectively at the calibration period. In this study, expanding of impervious surfaces such as greenhouses caused increasing of surface runoff, but caused decreasing of total nitrogen and total phosphorus loads.

• 한국습지학회지
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• 제3권2호
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• pp.133-142
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• 2001

Growth of cities and an increase in population result in the development-oriented policy, urban streams to lose their natural characteristics and functions by channelization, parking lot construction, and so forth. The streams fall into urban drains, which is the current status of urban streams. Recently, the interest in the stream environment and the ecosystem has been increased, and the efforts have been made to improve the traditional maintenance program for small streams. These efforts lead to the application of the natural recovery systems. This study applied the 240-meter model reach along the Oncheon stream, which locates in Dongrae-gu, Busan city. to analyze the natural recovery system. The efficiency of each system has been analyzed and the future improvements for the systems are presented. The results show that the stream maintenance program should consider the ecological environment. thereby minimizing the environmental effects. When the changes are inevitable, the maintenance program should adopt the methods. which closely simulate the original environmental elements. or are more favorable to the ecosystem.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1318-1321
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• 2005

As recently raw water quality has been polluted as well as its quality has been remarkably varied according to season and region, the precise control of coagulant dosage is being keenly required in water treatment plants. The amount of coagulant is closely related to raw water quality such as turbidity, alkalinity, water temperature, pH, electrical conductivity, etc. Since the optimum quantity of chemicals is not yet finalized, so dosage rate must be decided by using jar test that takes one or two hours. Hereupon, the output signal of stream current and multi-regression on historical data were proposed to be applied to the coagulant dosing control. In consequence of applying the scheme to automatic determination of the dosage rate, it was testified that the determination of dosage rate was very effective in case it is performed as to real-time sensing of water quality and the output signal of stream current.

• The Korean Journal of Ecology
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• 제6권2호
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• pp.81-89
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• 1983

The change of environmental factors with flow rates were studied quantitatively for two rivers, the Nakdong River and the Sin stream, which have different basins in ecosystem structures, during short period after a heavy rain. In the Nakdong River, transparency, DO, alkalinity and hardness were negatively correlated with the flow rate by logarithmic function, but the concentration of SiO2 was relatively constant regardless of the flow chage. In the Sin stream, transparency, alkalinity, hardness and the concentration of NH3-N, NO2-N and SO4= showed negative correlation with the flow rate by logarithmic function. The ratios of maximum to minimum values for aquatic environmental factors during the samller than that for flow rate in the respective rivers (28 in the Nakdong R.; 50 in the Sin S.). Immediately after the heavy rain, the concentrations of NO2-N, NH3-N and PO4-P in the Sin stream were 8, 6 and 1 times as high as those in the Nakdong River, respectively, but in the stable flow state, those became 94, 25 and more than 10 times, respectively. The load for most of the dissolved environmental constituents changed similarly to the flow rate in both rivers. It is notable that, at the stable flow state, the loads for NH3-N (59g/sec) and NO2-N (3.3g/sec) in the Sin stream were 4.3 and 1.3 times as high as those in the Nakdong River.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.112-120
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• 2005

The injector, which is used in a 4-valve gasoline engine, is required to be maintained the dual stream because of the design of dual intake port. In addition, the spray characteristics of fuel injector have strong influence on engine performance, exhaust emission, fuel consumption, and especially the cold start condition for the port injection. So, commercial gasoline injectors off different type were inspected. Those are 2 hole,4 hole, air shroud 4 hole, and air shroud 4 hole injector with separator. The spray behavior of dual stream was researched by the visualization system and PDPA system was employed to measure the droplet size. Atomization is one of the most important characteristic, so droplet size distributions and SMD are investigated. And the spray characteristics of each injector are also analyzed such as the spray tip penetration, spray angle, and separation angle.

• 정보처리학회논문지C
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• 제9C권2호
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• pp.257-266
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• 2002

3GPP2 방식의 무선 데이터 통신에서는 Macro Mobility 지원을 위하여 Mobile IP가 이용되며 PDSN은 Foreign Agent의 기능을 수행한다. 이때 하나의 PDSN에서 다른 PDSN으로 Mobile Station이 이동할 경우 지원되는 이동성을 Macro Mobility라 한다. 본 논문은 Macro Mobility에서 발생할 수 있는 패킷의 손실 및 순서변경에 대한 가능성을 살펴보고, 이러한 문제점을 보완하기 위한 방법으로 패킷의 Down Stream과 Up Stream의 각 경우에 대하여 Handoff Sequence Control을 적용한 PDSN간의 seamless 핸드오프 알고리즘을 제시한다.