• Journal of Korea Water Resources Association
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• v.35 no.6
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• pp.685-692
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• 2002

It is very useful to estimate easily the various characteristics of streams and to manage objectively streams, as the order or grade among streams is determined by the natural characteristics and the degree of human utilization. With obtainable various statistics data and expert examination, we proposed the measurable evaluation index of "stream weight" considering the natural characteristics of streams, the utilization degree of streams and the social conditions of the regions crossed streams. The each stream weight is calculated as follows. Firstly, select the various factors which influence to streams in AHP. Secondly, determine the each weight of factors by the result of expert examination. Finally, sum up after multiplying the normalized factors by these two values. The stream weight can be used such divisions as the recognization of relative weight between streams, the determination of the stream management direction in the near future, the enhancement of the efficiency of stream management through the adjustment of the present stream grade and the determination of the management method concerned the stream weight as well.t as well.

• Journal of Korean Society on Water Environment
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• v.25 no.1
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• pp.125-135
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• 2009

Reliable long-term flows by SWAT-K model were applied to the relationship between stream flow and pollutant load derived from 8-day measured data of Ministry of Environment (MOE) in order to obtain continuous loadograph and evaluate accuracy in water quality modeling for the Chungju dam watershed. The measured flow were compared with flow duration curve from the model, and it showed that measured values corresponded to the almost full range of stream flow conditions except at Odae A. And there was significant relationship ($R^2=0.60{\sim}0.97$) between measured flow and water quality load at all unit-watersheds. Applying this relationship to simulated flows, continuous loadograph was obtained and compared with modeled pollutant loads. Although there were some differences during some dry and flood seasons, those were not significant and overall trend showed a good agreement. From the results, we would be able to derive a continuous loadograph based on measured data at total maximum daily loads (TMDLs) unit-watersheds on a national scale, in which stream flow and water quality have been measured at 8-day intervals since 2004, and this could be helpful to utilize distributed water quality models with difficulty in calibrating and validating parameters from lack of measured data at present.

• Journal of Wetlands Research
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• v.12 no.3
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• pp.99-106
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• 2010

In this study unit hydrograph and infiltration capacity curves have been determined based on rainfall-runoff data for the upper Ansung stream basin. Infiltration capacity curve also has been computed based on measurements of accumulated infiltration. Accumulated infiltration curve which has close relationship with unit hydrograph has been found in adopting the following two approach methods. In the first method the mean infiltration capacity with infiltration index method and the Kostiakov accumulation infiltration curves have been computed based on hydrological data for the GongDo gauging station of the upper Ansung stream basin. In the second method the accumulation curve has been determined through directly observed infiltration data for four points in the upper basin and has been compared with the infiltration capacity curves by three observed rainfall-runoff event.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.6
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• pp.1546-1564
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• 2012

Pattern-based query processing has not attracted much attention in wireless sensor network though its counterpart has been studied extensively in data stream. The methods used for data stream usually consume large memory and much energy. This conflicts with the fact that wireless sensor networks are heavily constrained by their hardware resources. In this paper, we use piece wise representation to represent sensor nodes' collected data to save sensor nodes' memory and to reduce the energy consumption for query. After getting data stream's and patterns' approximated line segments, we record each line's slope. We do similar matching on slope sequences. We compute the dynamic time warping distance between slope sequences. If the distance is less than user defined threshold, we say that the subsequence is similar to the pattern. We do experiments on STM32W108 processor to evaluate our strategy's performance compared with naive method. The results show that our strategy's matching precision is less than that of naive method, but our method's energy consumption is much better than that of naive approach. The strategy proposed in this paper can be used in wireless sensor network to process pattern-based queries.

• ETRI Journal
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• v.31 no.6
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• pp.795-802
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• 2009

This paper presents the design of an advanced terrestrial digital multimedia broadcasting (AT-DMB) baseband receiver SoC. The AT-DMB baseband is incorporated into a hierarchical modulation scheme consisting of high priority (HP) and low priority (LP) stream decoders. The advantages of the hierarchical modulation scheme are backward compatibility and an enhanced data rate. The structure of the HP stream is the same as that of the conventional T-DMB system; therefore, a conventional T-DMB service is possible by decoding multimedia data in an HP stream. An enhanced data rate can be achieved by using both HP and LP streams. In this paper, we also discuss a time deinterleaver that can deinterleave data for a time duration of 384 ms or 768 ms. The interleaving time duration is chosen using the LP symbol mapping scheme. Furthermore, instead of a Viterbi decoder, a turbo decoder is adopted as an inner error correction system to mitigate the performance degradation due to a smaller symbol distance in a hierarchically modulated LP symbol. The AT-DMB baseband receiver SoC is fabricated using 0.13 ${\mu}m$ technology and shows successful operation with a 50 mW power dissipation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.906-913
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• 2010

Sensors related to the geographic information are gathering strength as core technologies for various ubiquitous services like u-City project for the new town of the future to provide total information services by the high IT infrastructure. These sensors generate the very large real-time streaming data because these are set up and controlled with wide areas of the geographical distribution. On this, we propose an efficient spatial data stream processing system to support various u-GIS services based on geographic sensors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1264-1270
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• 2006

In this study, semi-two dimension numerical model(GSTARS 2.1 model) were applied to study on the hydraulic and sedimentologic characteristics of downstream channel section in Dal stream. GSTARS 2.1 model was applied for the four selected sediment transport formulas(Meyer-Peter and Muller, Acker and White's, Engelund and Hanson, Yang formula) from 1984 to 1992 measured data on each section. The simulation results of Meyer-Peter and Muller formula for long-term bed changes are good when compared to the measured data. When quantitatively compared, it appears that the results data is relatively underestimated compared to the 1992 measured data on each section. Using Meyer-Peter and Muller formula, analyse the effects of bed changes by stream tube number.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.2
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• pp.73-80
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• 2014

MapReduce is a widely used programming model for analyzing and processing Big data. Aggregate queries are one of the most common types of queries used for analyzing Big data. In this paper, we propose an efficient method for processing an aggregate query stream, where many concurrent users continuously issue different aggregate queries on the same data. Instead of processing each aggregate query separately, the proposed method processes multiple aggregate queries together in a batch by a single, optimized MapReduce job. As a result, the number of queries processed per unit time increases significantly. Through various experiments, we show that the proposed method improves the performance significantly compared to a naive method.

• Journal of Korea Multimedia Society
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• v.24 no.3
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• pp.423-430
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• 2021

Aiming Graph convolutional networks (GCNs) have achieved outstanding performances on skeleton-based action recognition. However, several problems remain in existing GCN-based methods, and the problem of low recognition rate caused by single input data information has not been effectively solved. In this article, we propose a Dual-stream fusion method that combines video data and skeleton data. The two networks respectively identify skeleton data and video data and fuse the probabilities of the two outputs to achieve the effect of information fusion. Experiments on two large dataset, Kinetics and NTU-RGBC+D Human Action Dataset, illustrate that our proposed method achieves state-of-the-art. Compared with the traditional method, the recognition accuracy is improved better.

• The Transactions of the Korea Information Processing Society
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• v.4 no.7
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• pp.1770-1780
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• 1997

Our problem is improvement of image quality because it is inevitable cell loss of image data when traffic congestion occurs. If cells are discarded indiscriminately in transmission of MPEG video data, it occurs severe degradation in quality of service(QOS). In this paper, to solve this problem, we propose two method. The first, we analyze the traffic characteristics of an MPEG encoder and generate high priority and low priority data stream. During network congestion, only the least low priority cells are dropped, and this ensures that the high priority cells are successfully transmitted, which, in turn, guarantees satisfactory QoS. In this case, the prioritization scheme for the encoder assigns components of the data stream to each priority level based on the value of a parameter ${\beta}$. The second, Number of high priority cells are increased when value of ${\beta}$ is large. It occurs the loss of high priority cell in the congestion. To prevent it, this paper is regulated to data stream rate as buffer occupancy with UPC controller. Therefore, encoder's bandwidth can be calculated renegotiation of the encoder and networks. In this paper, the encoder's bandwidth requirements are characterized by a usage parameter control (UPC) set consisting of peak rate, burstness, and sustained rate. An adaptive encoder rate control algorithm at the Networks Interface Card(NIC) computes the necessary UPC parameter to maintain the user specified quality of service. Simulation results are given for a rate-controlled VBR video encoder operating through an ATM network interface which supports dynamic UPC. These results show that dynamic bandwidth renegotiation of prioritized data stream could provided bandwidth saving and significant quality gains which guarantee high priority data stream.