• Journal of Environmental Science International
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• v.19 no.12
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• pp.1375-1384
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• 2010

The purpose of this research is to understand the change of runoff characteristics by estimated spatial rainfall. Therefore, this paper largely composed of two parts. First, we compared the simulated result according to estimation method, ID(Inverse Distance Method, ID2(Inverse Square Distance Method), and Kr(General Covariance Kriging Method), after letting miss rainfall data to the observed data. Second, we reviewed the runoff characteristics of the distributed runoff model according to the estimated spatial rainfall. On the basis of Yuseong water level station, we select the target basin as Gabchun watershed. We assumed 1 point or 2 point of the 6 rainfall gauge stations in watershed were missed. We applied the spatial rainfall distributed by Kr to Hy-GIS GRM, distributed runoff model. When 1 point rainfall data is missed, Kr is superior to others in point rainfall estimation and runoff estimation of Hy-GIS GRM. However, in case rainfall data of 2 points is missed, all of three methods did not give suitable result for them. In conclusion, Kr showed better applicability than other estimated methods if rainfall's data less than 2 points is missed.

• Journal of Korean Society on Water Environment
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• v.26 no.2
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• pp.252-260
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• 2010

The point rainfall measurements need to be converted to the areal rainfall by means of mean areal precipitation (MAP) estimation methods. And it is not appropriate to evaluate the areal rainfall with constant drift because of the geomorphological influences to rainfall field. Non-stationarity should be applied to the estimation of the areal rainfall, therefore, to consider these effects. Kriging methods with special functional would be a suitable tool in this case. Generalized covariance Kriging method is the most developed one among different Kriging methods. From this point of view this study performs the analysis of its applicability to distributed runoff model. For these purpose, distributed rainfall was created by Thiessen and Kriging method. And distributed rainfall of each method was applied into HyGIS-GRM. The result of applying, Runoff was different in the rainfall data form. Therefore, To apply Kriging method with physical meaning is that it is the useful method as distributed rainfall-runoff model.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.35-42
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• 2010

Side information generation techniques play a great role in determining the overall performance of the DVC (Distributed Video Coding) coding system. Most conventional techniques for side information generation are mainly based on the block matching algorithm with symmetric motion estimation between the previously reconstructed key frames. But, these techniques tend to show mismatches between the motion vectors and the real placements of moving objects. So these techniques need to be modified so as to search well the real placements of moving objects. To overcome this problem, this paper proposes a block-centered symmetric motion estimation technique which uses the same coordinates with the given block. Through computer simulations, it is shown that the proposed algorithm outperforms the conventional schemes in the objective quality.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2400-2413
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• 2019

Doubly-selective (DS) fading channel is often occurred in many orthogonal frequency division multiplexing (OFDM) communication systems, such as high-speed rail communication systems and underwater acoustic (UWA) wireless networks. It is challenging to provide an accurate and fast estimation over the doubly-selective channel, due to the strong Doppler shift. This paper addresses the doubly selective channel estimation problem based on complex exponential basis expansion model (CE-BEM) in OFDM systems from the perspective of distributed compressive sensing (DCS). We propose a novel DCS-based improved sparsity adaptive matching pursuit (DCS-IMSAMP) algorithm. The advantage of the proposed algorithm is that it can exploit the joint channel sparsity information using dynamic threshold, variable step size and tailoring mechanism. Simulation results show that the proposed algorithm achieves 5dB performance gain with faster operation speed, in comparison with traditional DCS-based sparsity adaptive matching pursuit (DCS-SAMP) algorithm.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.5 s.149
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• pp.597-603
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• 2006

The estimations of distributed and joint-excited input power for Power Flow Analysis are accomplished in this paper. Using Fourier transform, the displacements of infinite structures are derived, and the input power of distributed excitation can be estimated. The obtained results compare the real input power with the estimation of input power. When the exciting force acts on the joint of coupled structures, it is estimating the power that is transferred to each structure. Appling this input power, the results of energy density and intensity of Power Flow Analysis can be compared with the classical solutions.

• The Journal of Korea Robotics Society
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• v.2 no.4
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• pp.310-316
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• 2007

The paper proposes a human-following behavior of mobile robot and an intelligent space (ISpace) is used in order to achieve these goals. An ISpace is a 3-D environment in which many sensors and intelligent devices are distributed. Mobile robots exist in this space as physical agents providing humans with services. A mobile robot is controlled to track a walking human using distributed intelligent sensors as stably and precisely as possible. The moving objects is assumed to be a point-object and projected onto an image plane to form a geometrical constraint equation that provides position data of the object based on the kinematics of the intelligent space. Uncertainties in the position estimation caused by the point-object assumption are compensated using the Kalman filter. To generate the shortest time trajectory to track the walking human, the linear and angular velocities are estimated and utilized. The computer simulation and experimental results of estimating and trackinging of the walking human with the mobile robot are presented.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1333-1343
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• 2016

Spectrum sharing in centrally controlled cognitive radio (CR) networks has been widely studied, however, research on channel access for distributively controlled individual cognitive users has not been fully characterized. This paper conducts an analysis of random channel access of cognitive users controlled in a distributed manner in a CR network. Based on the proposed estimation method, each cognitive user can estimate the current channel condition by using its own Markov-chain model and can compute its own blocking probability, collision probability, and forced termination probability. Using the proposed scheme, CR with distributed control (CR-DC), CR devices can make self-controlled decisions based on the status estimations to adaptively control its system parameters to communicate better.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.6
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• pp.119-130
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• 2010

The universal model for the parameter estimation of the Storage Function Model(SFM) was developed through the applications of the distributed model for various hypothetical watersheds and runoff conditions. The existing parameter estimation equations are based on observations and these equations which are derived from the restricted conditions are not sensitive to the variation of physical characteristics of a watershed. This study developed the universal model for the parameter estimation through the runoff simulations of 35,000 times. As the simulation results, we have known that the lag time is related to the longest stream channel characteristics and the storage coefficient is related to the watershed characteristics.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.257-262
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• 2000

Recently, though there are many REES(Remote Education Estimation Systems), they have some tied and complete testing method not considering for the student individual specification and characteristic. This paper proposes the education model of the distributed asynchronous communication method which making a test without me and place limits using web estimation system from problem bank database, and attach effective method could improve student achievement, quality of estimation later problem filtering using user profile in order to consider the student individual difference and characteristic that not considered pre-Remote Education Estimation Systems. This is a adaptive DAC method improving the pre-DAC method.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.2 s.314
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• pp.74-81
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• 2007

In this paper, an efficient SAD(Sum of Absolute Differences) processor structure for motion estimation of H.264 is proposed. SAD processors are commonly used both in full search methods for motion estimation and in fast search methods for motion estimation. Proposed structure consists of SAD calculator block, combinator block, and minimum value calculator block. Especially, proposed structure is simplified by using Distributed Arithmetic for addition operation. The Verilog-HDL(Hard Description Language) coding and FPGA(Field Programmable Gate Array) implementation results for the proposed structure show 39% and 32% gate count reduction in comparison with those of the conventional structure, respectively. Due to its efficient processing scheme, the proposed SAD processor structure can be widely used in size dominant H.264 chip.