• The Transactions of the Korea Information Processing Society
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• v.5 no.6
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• pp.1610-1619
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• 1998

The ABR service class provides feedback based traffic control to transport bursty data traffic efficiently. Feedback based congestion control has first been studied to be applied to unicast connections. Recently. several congestion control algorithms for multicast connections have also been proposed as the number of ABR applications requiring multicast increases. With feedback based congestion control, the effectiveness of a traffic control scheme diminishes as propagation delay increases. Especially for a multicast connection, a remote destination may suffer unfair service compared to a local destination due to the delayed feedback. Amelioration of the disadvantages caused by feedback delay is therefore more important for remote destinations in multicast connections. This paper proposes a new switch behavior to provide effective feedback based mathc control for rentoh destinations. The proposed switches adjust the service rate dynamically in accordance woth the state of the downstream, that is, the congestion of the destinaion is immediately controlled by the nearest apstream switch before the source to ramp down the transmission rate of the connection. The proposed switch has an implementation overhead to have a separate buffer for each VC to adjust the service rate in accordance with a backward Rm cell of each VC. The buffer requirement id also increased at intermediate switches. Simulation results show that the proposed switch reduces the cell loss rate in both the local and the remote destinations and slso amelioratd the between the two destinations.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.2
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• pp.21-28
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• 2010

This paper reports an experimental result on optimizing dissimilarity-based classification(DBC) by simultaneously using a dynamic time warping(DTW) and a multiple fusion strategy(MFS). DBC is a way of defining classifiers among classes; they are not based on the feature measurements of individual samples, but rather on a suitable dissimilarity measure among the samples. In DTW, the dissimilarity is measured in two steps: first, we adjust the object samples by finding the best warping path with a correlation coefficient-based DTW technique. We then compute the dissimilarity distance between the adjusted objects with conventional measures. In MFS, fusion strategies are repeatedly used in generating dissimilarity matrices as well as in designing classifiers: we first combine the dissimilarity matrices obtained with the DTW technique to a new matrix. After training some base classifiers in the new matrix, we again combine the results of the base classifiers. Our experimental results for well-known benchmark databases demonstrate that the proposed mechanism achieves further improved results in terms of classification accuracy compared with the previous approaches. From this consideration, the method could also be applied to other high-dimensional tasks, such as multimedia information retrieval.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.4
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• pp.365-372
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• 2006

A dynamic compartment model is presented to predict the contamination level of agricultural plant by $^{137}C_s$ as a result of a soil deposition. The model considered the processes of a percolation, soil mixing by a plowing before transplanting, plant uptake, leaching to a deep soil, and fixation to a clay mineral. The effects of the soil properties (pH, clay mineral, organic matter content, and exchangeable K), which are spatially varied, on a plant uptake and the leaching rates of $^{137}C_s$ in a root zone soil were modeled by the Absalom model. To test the validity of the model, the $^{137}C_s$ aggregated transfer factors(TFa) for rice plants were compared with those observed from some simulated $^{137}C_s$ soil deposition experiments, which were carried out with respect to rice plants cultivated in seventeen paddy soils of different properties for two consecutive years. Observed $^{137}C_s$ TFa values of the rice plants did not show an evident trend for the pH and clay content of the soil properties, while they increased with an increasing organic matter content or a decreasing exchangeable K concentration. Predicted $^{137}C_s$ TFa values of the rice plants were found to be comparable with those observed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1450-1458
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• 2011

The HPcN (Hybrid & high Performance Convergence Network) in research networks means environment which can provide both computing resource such as supercomputer, cluster and network resource to application researchers in the field of medical, bio, aerospace and e-science. The most representative research network in Korea, KREONET has been developing following technologies through the HERO (Hybrid Networking project for research oriented infrastructure) from 200S. First, we have constructed and deployed a control plane technology which can provide a connection oriented network dynamically. Second, the integrated resource management system technology has been developing for reservation and allocation of both computing and network resources, whenever users want to utilize them. In this paper, a testbed network is presented, which is possible to reserve and allocate network resource using the integrated resource management system. We reserve network resource through GNSI (Grid Network Service Interface) messages between GRS (Global Resource Scheduler) and NRM (Network Resource Manager) and allocate network resource through GUNI (Grid User Network Interface) messages between the NRM (network resource manager) and routers, based on reservation information provided from a user on the web portal. It is confirmed that GUNI interface messages are delivered from the NRM to each router at the starting of reservation time and traffic is transmitted through LSP allocated by the NRM.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.3
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• pp.209-219
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• 2004

In order to implement a real time hardware for keyword spotting, we propose a Single-End-Point DTW(SEP-DTW) algorithm which is simple and less complex for computation. The SEP-DTW algorithm only needs a single end point which enables efficient applications, and it has a small wont of computations because the global search area is divided into successive local search areas. Also, we adopt new local constraints and a new distance measure for a better performance of the SEP-DTW algorithm. Besides, we make a normalization of feature same vectors so that they have the same variance in each frequency bin, and each frame has the same energy levels. To construct several reference patterns for each keyword, we use a clustering algorithm for all training patterns, and mean vectors in every cluster are taken as reference patterns. In order to detect a key word for input streams of speech, we measure the distances between reference patterns and input pattern, and we make a decision whether the distances are smaller than a pre-defined threshold value. With isolated speech recognition and keyword spotting experiments, we verify that the proposed algorithm has a better performance than other methods.

• Journal of the Korean Society for Railway
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• v.19 no.3
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• pp.388-396
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• 2016

The metropolitan subway network of Seoul has gone through many evolutionary processes in past decades to disperse the floating population and improve the traffic flow. In this study, we analyzed how the structural characteristics and the efficiency of the subway network have changed according to the dynamic evolutionary processes of the metropolitan subway network of Seoul. We have also proposed new measures that can be used to characterize the structural properties of the subway network more practically. It is shown that the global efficiency is about 74%, which is higher than those of subway networks of foreign countries. It should also be considered that passenger flow between stations is even higher, at about 85%. Since the private lines, including line 9, the New Bundang line, the Uijeongbu line, and the Ever line do not release their traffic data since September, 2013, only 5 years of data from September, 2008 to September, 2013 is available. So, in this study we limit the analysis period to these 5 years.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.3
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• pp.220-225
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• 2015

In this study, the effect of stationary fin and buoyancy devices on dynamic pithing of the tracked vehicle was investigated. For this work, the stationary fin and buoyancy devices were installed in front of body and then pitching variation was measured when rapidly reducing the vehicle speed in water operation. According to the results of measuring the freeboard at each case, when only fin was installed, the effect on freeboard of tracked vehicle in water was negligible. However, when buoyancy devices were installed, front freeboard was approximately increased by about 20~25 mm and rear freeboard was decreased by about 10~15 mm per each addition of 100 kg buoyancy device. Based on the calculation result of pitching decrease rates, it was found that the pitching variation was decreased approximately 12.3 % by fin installation and approximately 2 % by installation of each 100 kg of buoyancy device. The case in which only fin installation was made showed the best efficiency in decreasing pitching variation of the tracked vehicle in water compared to the other cases.

• Journal of the Korean GEO-environmental Society
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• v.9 no.6
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• pp.61-70
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• 2008

In this study, undrained triaxial (CU) tests were performed on low-plastic silt of Nakdong River in order to investigate the undrained shear behavior of low-plastic silt. In experimental results, the deviator stress showed the hardening behavior after reaching its yield stress like the tendency of common sand, and the pore water pressure was gradually decreased to critical state after the maximum value. In the effective stress paths, regardless of consolidation stress or overconsolidation ratios, both a critical state line (CSL) and a phase transformation line (PTL) exist in the effective stress path that is similar to the case of sand. The behavior of low-plastic silt was predicted by the Modified Cam-Clay (MCC) model, the Jordan and the Elman-jordan model that is artificial neural network model. According to predicted results, the overall undrained shear behavior of low-plastic silt could not be predicted with the MCC model, but the Jordan and Elman-Jordan model showed well-matched experiment results.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.4 s.316
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• pp.86-92
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• 2007

A discrete dynamic model for tracking feature points in 2D images is developed. Conventional snake approaches deform a contour to lock onto features of interest within an image by finding a minimum of its energy functional, composed of internal and external forces. The neighborhood around center snaxel is a space matrix, typically rectangular. The structure of the model proposed in this paper is a set of connected vertices. Energy model is designed for its local minima to comprise the set of alternative solutions available to active process. Block on tracking is one dimension, line type. Initial starting points are defined to the satisfaction of indent states, which is then automatically modified by an energy minimizing process. The track is influenced by curvature constraints, ascent/descent or upper/lower points. The advantages and effectiveness of this layer approach may also be applied to feature points tracking of digital image whose pixels have one directional properties with high autocorrelation between adjacent data lines, vertically or horizontally. The test image is the ultrasonic carotid artery image of human body, and we have verified its effect on intima/adventitia starting points tracking.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.108-116
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• 2008

In this paper, we propose an algorithm that can estimate the distance using disparity based on stereo vision system, even though the obstacle is located in long ranges as well as short ranges. We use sub-pixel interpolation to minimize quantization errors which deteriorate the distance accuracy when calculating the distance with integer disparity, and also we use enhanced adaptive fuzzy strong tracking Kalman filter(EAFSTKF) to improve the distance accuracy and track the path optimally. The proposed method can solve the divergence problem caused by nonlinear dynamics such as various vehicle movements in the conventional Kalman filter(CKF), and also enhance the distance accuracy and reliability. Our simulation results show that the performance of our method improves by about 13.5% compared to other methods in point of root mean square error rate(RMSER).