• The Transactions of The Korean Institute of Electrical Engineers
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• 제61권8호
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• pp.1199-1203
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• 2012

H.264 adopted many compression tools to increase image data compression efficiency such as B frame bi-directional predictions, the direct mode coding and so on. Despite its high compression efficiency, H.264 can suffer from its long coding time due to the complicated tools of H.264. To realize a high performance H.264, several fast algorithms were proposed. One of them is adaptive fast direct mode decision algorithm using mode and Lagrangian cost prediction for B frame in H.264/AVC (MLP) algorithm which can determine the direct coding mode for macroblocks without a complex mode decision process. However, in this algorithm, macroblocks not satisfying the conditions of the MLP algorithm are required to process the complex mode decision calculation, yet suffering a long coding time. To overcome the problem, this paper proposes a fast direct mode prediction algorithm. Simulation results show that the proposed algorithm can determine the direct mode coding without a complex mode decision process for 42% more macroblocks and, this algorithm can reduce coding time by up to 23%, compared with Jin's algorithm. This enables to encode B frames fast with a less quality degradation.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제59권2호
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• pp.407-410
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• 2010

This paper presents an advanced load allocation algorithm in Direct Load Control(DLC) system. It is important to aggregate a various demand side resource which is surely controllable at the peak power time for a successful DLC system. Previous load allocation algorithm appropriate for DLC system is based on interchanged information, but, this algorithm can not derive optimal solutions. In this paper, we develop the optimal algorithm and the new load allocation algorithm in polynomial time. The simulation results show that the proposed heuristic algorithm for DLC system is very effective.

• ETRI Journal
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• 제45권3호
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• pp.394-403
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• 2023

Direct tracking problem of moving noncircular sources for multiple arrays is investigated in this study. Here, we propose an improved unscented particle filter (I-UPF) direct tracking method, which combines system proportional symmetry unscented particle filter and Markov Chain Monte Carlo (MCMC) algorithm. Noncircular sources can extend the dimension of sources matrix, and the direct tracking accuracy is improved. This method uses multiple arrays to receive sources. Firstly, set up a direct tracking model through consecutive time and Doppler information. Subsequently, based on the improved unscented particle filter algorithm, the proposed tracking model is to improve the direct tracking accuracy and reduce computational complexity. Simulation results show that the proposed improved unscented particle filter algorithm for noncircular sources has enhanced tracking accuracy than Markov Chain Monte Carlo unscented particle filter algorithm, Markov Chain Monte Carlo extended Kalman particle filter, and two-step tracking method.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
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• pp.281-284
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• 2004

This paper presents the design and implementation of a QoS based enhanced collaboration system in MDO. This is an efficient distributed communication tool between designers. It supports text communication, audio/video communication, file transfer and XML data sending/receiving. Specially, this system supports a dynamic QoS self-adaptation by using the improved direct adjustment algorithm (DAA+). The original direct adjustment algorithm adjusts the transmission rate according to the congestion level of the network, based on the end to end real time transport protocol (RTP), and controls the transmission rate by using the information of loss ratio in real time transport control protocol (RTCP). But the direct adjustment algorithm does not consider when the RTCP packets are lost. We suggest an improved direct adjustment algorithm to solve this problem. We apply our improved direct adjustment algorithm to our of QoS (Quality of Service) [1] based collaboration system and show the improved performance of transmission rate and loss ratio.

• Journal of the Korean Institute of Telematics and Electronics A
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• 제32A권7호
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• pp.8-15
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• 1995

We have proposed a new fast serial serch algorithm and a receiver for direct-sequence spead-spectrum acquisition systems and analyzed its perfoemance. This algorithm achieves faster acquisition by more than two times that of existing algorithm. We have derived equations of the mean acquistion time by using moment generating function and direct approach, and presented numerical results.

• Journal of the Korean Geosynthetics Society
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• 제23권1호
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• pp.27-37
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• 2024

In this study, direct algorithm-based back analysis was utilized to perform back analysis on two actual earth retaining wall fields, which was then compared with genetic algorithm-based method to evaluate the suitability of the back analysis. Additionally, in order to propose effective utilization methods of the program, the measurement data, as the input for the back analysis, was varied for each excavation step, and the applicability of the back analysis results(displacement, axial force) was examined. The research findings indicate that both direct algorithm and genetic algorithm show high applicability; however, the optimization for this program is better predicted by the direct algorithm. Moreover, in order to effectively use the back analysis program employing the direct algorithm, it was evaluated that relatively accurate prediction of the earth retaining wall behavior could be achieved by inputting measurement data from the 7th excavation step for fields with final excavation steps ranging from 8 to 11.

• Journal of the Korean Society for Precision Engineering
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• 제12권10호
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• pp.25-31
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• 1995

In this paper, a direct drive scalar robot manipulator is constructed and its mechanical machanism for operation is explained. Also, a motion controller board for the direct drive robot manipulator was developed where the IBM 486 computer is the main controller. For the developed direct drive robot, a force/motion control algorithm based on an active compliance scheme is developed. A preliminary experiment using the developed direct drive for a peg-in-hole job was done by implementing the control algorithm.

• Proceedings of the KIEE Conference
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.377-380
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• 1992

This paper proposes a novel direct adaptive pole placement control algorithm which can be applied to continuous time nonminimum phase systems. The algorithm is based on Lyapunov's direct method. By introducing an auxiliary signal, a minimal error model is constructed in state space. Using the error model an estimation law is obtained via Lyapunov's second stability theorem. The global stability of the overall system is established.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제21권11호
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• pp.1819-1826
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• 1997

Direct-drive robots are suitable to the position and force control with high accuracy, but it is difficult to design a controller because of the system's nonlinearity and link-interactions. This paper is concerned with the study of the force control of direct-drive robots. The proposed algorithm consists of feedback controllers and a neural network. After the completion of learning, the output of feedback controller is nearly equal to zero, and the neural network controller plays an important role in the control system. Therefore, the optimum retuning of parameters of feedback controllers is unnecessary. In other words, the proposed algorithm does not require any knowledge of the controlled system in advance. The effectiveness of the proposed algorithm is demonstrated by the experiment on the force control of the parallelogram link-type direct-drive robot.

• Journal of Korean Institute of Industrial Engineers
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• 제31권4호
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• pp.303-315
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• 2005

In this paper we address a design problem for hub-and-spoke networks and then consider a capacitated hub locations problem with direct shipment (CHLPwD). We determine the location of hubs, the allocation of nodes to hubs, and direct shipment paths in the network, with the objective of minimizing the total cost in the network. In this paper, CHLPwD is formulated as 0-1 integer programming. We develop an evolutionary algorithm here to solve the large sized CHLPwD. To do this, we present the representation and the genetic operators suitable for the problem and propose a heuristic method for the allocation of nodes to hubs. To enhance the search capability, problem-specific information is used in our evolutionary algorithm. The proposed algorithm is compared with the heuristic method in terms of solution quality and computation time. The experimental results show that our algorithm can provide better solutions than the heuristic.