• Title/Summary/Keyword: Computation load

Search Result 472, Processing Time 0.027 seconds

A Study on Improvement of Run-Time in KS-SIGNAL, Traffic Signal Optimization Model for Coordinated Arterials (간선도로 연동화 신호최적화 모형 KS-SIGNAL의 수행속도 향상을 위한 연구)

  • 박찬호;김영찬
    • Journal of Korean Society of Transportation
    • /
    • v.18 no.4
    • /
    • pp.7-18
    • /
    • 2000
  • KS-SIGNAL, a traffic signal optimization model for coordinated arterials, is an optimization model using the mixed integer linear Programming that minimizes total delay on arterials by optimizing left-turn Phase sequences. However, the Previous version of KS-SIGNAL had a difficulty in reducing computation speed because the related variables and constraints multiply rapidly in accordance with the increase of intersections. This study is designed to propose a new model, improving optimizing computation speed in KS-SIGMAl, and evaluate it. This Paper Puts forth three kinds of methodological approaches as to achieve the above goals. At the first step to reduce run-time in the proposed model objective function and a few constraints are Partially modified, which replaces variable in related to queue clearance time with constant, by using thru-movements at upstream intersection and the length of red time at downstream intersection. The result shows that the run-time can be reduced up to 70% at this step. The second step to load the library in LINDO for Windows, in order to solve mixed integer linear programming. The result suggests that run-time can be reduced obviously up to 99% of the first step result. The third step is to add constraints in related to left-turn Phase sequences. The proposed methodological approach, not optimizing all kinds of left-turn sequences, is more reasonable than that of previous model , only in the view of reducing run-tim. In conclusion, run-time could be reduced up to 30% compared with the second results. This Proposed model was tested by several optimization scenarios. The results in this study reveals that signal timing plan in KS-SIGNAL is closer to PASSER-II (bandwidth maximizing model) rather than to TRANSYT-7F(delay minimizing model).

  • PDF

Multi-tracer Imaging of a Compton Camera (다중 추적자 영상을 위한 컴프턴 카메라)

  • Kim, Soo Mee
    • Progress in Medical Physics
    • /
    • v.26 no.1
    • /
    • pp.18-27
    • /
    • 2015
  • Since a Compton camera has high detection sensitivity due to electronic collimation and a good energy resolution, it is a potential imaging system for nuclear medicine. In this study, we investigated the feasibility of a Compton camera for multi-tracer imaging and proposed a rotating Compton camera to satisfy Orlov's condition for 3D imaging. Two software phantoms of 140 and 511 keV radiation sources were used for Monte-Carlo simulation and then the simulation data were reconstructed by listmode ordered subset expectation maximization to evaluate the capability of multi-tracer imaging in a Compton camera. And the Compton camera rotating around the object was proposed and tested with different rotation angle steps for improving the limited coverage of the fixed conventional Compton camera over the field-of-view in terms of histogram of angles in spherical coordinates. The simulation data showed the separate 140 and 511 keV images from simultaneous multi-tracer detection in both 2D and 3D imaging and the number of valid projection lines on the conical surfaces was inversely proportional to the decrease of rotation angle. Considering computation load and proper number of projection lines on the conical surface, the rotation angle of 30 degree was sufficient for 3D imaging of the Compton camera in terms of 26 min of computation time and 5 million of detected event number and the increased detection time can be solved with multiple Compton camera system. The Compton camera proposed in this study can be effective system for multi-tracer imaging and is a potential system for development of various disease diagnosis and therapy approaches.

Fast Scene Change Detection Using Macro Block Information and Spatio-temporal Histogram (매크로 블록 정보와 시공간 히스토그램을 이용한 빠른 장면전환검출)

  • Jin, Ju-Kyong;Cho, Ju-Hee;Jeong, Jae-Hyup;Jeong, Dong-Suk
    • Journal of the Institute of Electronics Engineers of Korea SP
    • /
    • v.48 no.1
    • /
    • pp.141-148
    • /
    • 2011
  • Most of the previous works on scene change detection algorithm focus on the detection of abrupt rather than gradual changes. In general, gradual scene change detection algorithms require heavy computation. Some of those approaches don't consider the error factors such as flashlights, camera or object movements, and special effects. Many scenes change detection algorithms based on the histogram show better performances than other approaches, but they have computation load problem. In this paper, we proposed a scene change detection algorithm with fast and accurate performance using the vertical and horizontal blocked slice images and their macro block informations. We apply graph cut partitioning algorithm for clustering and partitioning of video sequence using generated spatio-temporal histogram. When making spatio-temporal histogram, we only use the central block on vertical and horizontal direction for performance improvement. To detect camera and object movement as well as various special effects accurately, we utilize the motion vector and type information of the macro block.

Fast Intra Mode Decision for H.264/AVC by Using the Approximation of DCT Coefficient (H.264/AVC에서 DCT 계수의 근사화를 이용한 고속 인트라 모드 결정 기법)

  • La, Byeong-Du;Eom, Min-Young;Choe, Yoon-Sik
    • Journal of the Institute of Electronics Engineers of Korea SP
    • /
    • v.44 no.3
    • /
    • pp.23-32
    • /
    • 2007
  • The H.264/AVC video coding standard uses rate distortion optimization (RDO) method to improve the compression performance in the intra prediction. The complexity and computational load are increased more than previous standard by using this method, even though this standard selects the best coding mode for the current macroblock. This paper proposes a fast intra mode decision algorithm for H.264/AVC encoder based on dominant edge direction (DED). To apply the idea, this algorithm uses the approximation of discrete cosine transform (DCT) coefficient. By detecting the DED, 3 modes instead of 9 modes are chosen for RDO calculation to decide the best mode in the $4{\times}4$ luma block. As for the $16{\times}16$ luma and $8{\times}8$ chroma block, instead of 4 modes, only 2 modes are searched. Experimental results show that the computation time of the proposed algorithm is decreased to about 72% of the full search method with negligible quality loss.

Estimation of the Axial Stiffness of Reinforcing Piles in Vertical Extension Structures (수직증축 공동주택 하부 신설 보강말뚝의 축강성 산정)

  • Kim, Do-Hyun;Jeong, Sang-Seom;Cho, Hyun-Chul
    • Journal of the Korean Geotechnical Society
    • /
    • v.35 no.12
    • /
    • pp.35-44
    • /
    • 2019
  • In this study, the axial stiffness of reinforcing piles (Kvr) for the vertical extension remodeling structures was estimated through 3D finite element analysis. In the computation of the minimum required axial stiffness of reinforcing piles, proposed maximum axial stiffness of old and deteriorated existing piles (Kve) based on theoretical and experimental approaches will be applied. Through this, the required increase rate of axial stiffness of reinforcing piles in order to support the increased structural loading was proposed for end-bearing and friction piles by different slenderness ratio (L/D). The numerical model was validated by comparing the computed results with actual field measurements. Based on the computed results, it was concluded that the end-bearing reinforcing pile needs 44% - 67% increase in axial stiffness to deal with the deterioration of existing piles and support the additional structural load due to vertical extension remodeling.

3D Model Extraction Method Using Compact Genetic Algorithm from Real Scene Stereoscopic Image (소형 유전자 알고리즘을 이용한 스테레오 영상으로부터의 3차원 모델 추출기법)

  • Han, Gyu-Pil;Eom, Tae-Eok
    • Journal of the Institute of Electronics Engineers of Korea SP
    • /
    • v.38 no.5
    • /
    • pp.538-547
    • /
    • 2001
  • Currently, 2D real-time image coding techniques had great developments and many related products were commercially developed. However, these techniques lack the capability of handling 3D actuality, occurred by the advent of virtual reality, because they handle only the temporal transmission for 2D image. Besides, many 3D virtual reality researches have been studied in computer graphics. Since the graphical researches were limited to the application of artificial models, the 3D actuality for real scene images could not be managed also. Therefore, a new 3D model extraction method based on stereo vision, that can deal with real scene virtual reality, is proposed in this paper. The proposed method adapted a compact genetic algorithm using population-based incremental learning (PBIL) to matching environments, in order to reduce memory consumption and computational time of conventional genetic algorithms. Since the PBIL used a probability vector and competitive learning, the matching algorithm became simple and the computation load was considerably reduced. Moreover, the matching quality was superior than conventional methods. Even if the characteristics of images are changed, stable outputs were obtained without the modification of the matching algorithm.

  • PDF

Sloshing Impact Response Analysis for Insulation System of LNG CCS Considering Elastic Support Effects of Hull Structures (선체구조의 탄성지지 효과를 고려한 LNG 운반선 방열구조의 슬로싱 충격응답 해석법에 관한 연구)

  • Nho, In Sik;Ki, Min-Seok;Kim, Sung-Chan;Lee, Jang Hyun;Kim, Yonghwan
    • Journal of Ocean Engineering and Technology
    • /
    • v.31 no.5
    • /
    • pp.357-363
    • /
    • 2017
  • The sloshing pressure acting on a membrane-type LNG CCS is a typical irregular impact load, and the structural response of a tank system induced by sloshing also shows very complex behavior, including fluid structure interaction. Therefore, it is not easy to accurately estimate the sloshing impact pressures and resulting structural response. Moreover, a huge time consuming process to deal with the enormous pressure data obtained during a model tank test and the following structural analysis would be inevitable. To reduce the computation time for structural analysis, in this study, a rational structural modeling strategy was considered, and a simplified scheme to analyze the dynamic structural responses of an LNG CCS was introduced, which was based on the concept of the linear combination of the triangular response functions obtained by a transient response analysis of structures under unit triangular impact pressure. A structural analysis of a real Mark III membrane type insulation system under the sloshing impact pressure time histories obtained by model tests was performed using the various proposed structural models and simplified analysis scheme. The results were investigated in detail, including the elastic support effects of the hull structure.

A dual-link CC-NUMA System Tolerant to the Multiprogramming Environment (다중 프로그램 환경에 적합한 이중 연결 CC-NUMA 시스템)

  • Suh, Hyo-Joong
    • The KIPS Transactions:PartA
    • /
    • v.11A no.3
    • /
    • pp.199-206
    • /
    • 2004
  • Under the multiprogrammed situation, the performance of multiprocessor system is affected by the process allocation policy of the operating systems. The lowest communication cost can be achieved when the related processes positioned to the adjacent processors. While the effective allocation is quite difficult to the real situation, and the processing of the allocation policy consumes some computation time. The dual-ring CC-NUMA systems exhibit a quite performance difference according to the process a1location policy due to a lot of unbalanced memory transactions on the interconnection networks. In this paper, I propose a load balanced dual-link CC-NUMA system that does not requires the processes allocation policy. By the program-driven simulation results. the proposed system shows no remarkable difference according to the allocation policy while the dual-ring systems shows 10% performance improvement by the process allocation. In addition, the proposed system outperforms the dual~ring systems about 1.5 times.

The Calculation of Illuminance Distribution in Complex Interior using Montecarlo Simulation (몬테카를로 시뮬레이션을 이용한 다면 공간의 조도계산)

  • Kim, Hee-Chul;Chee, Chul-Kon;Kim, Hoon
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.7 no.6
    • /
    • pp.27-33
    • /
    • 1993
  • In order to improve complicated construction and complex control which are didvantage of optimal PWM technique aimed at harmonic elimination method, this paper presented MRA(Mode1 Reference Adaptive) PWM technique that gating signal of inverter is generated by comparing the reference signal with the induced feedback signal at the reference model of load. Design of controller is composed of microprocessor and analog circuit. MRA PWM technique used in the paper is able to compensate the degradation of voltage efficiency to be generated by the ratio of the output voltage to the DC supply voltage being low for using conventional sinusoidal PWM technique. When the trapezoidal signal is employed as the reference signal. the low order harmonics of line current can be reduced and the switching pattern is made by on-line computation using comparatively simple numerical analysis.

  • PDF

Moment-based Fast CU Size Decision Algorithm for HEVC Intra Coding (HEVC 인트라 코딩을 위한 모멘트 기반 고속 CU크기 결정 방법)

  • Kim, Yu-Seon;Lee, Si-Woong
    • The Journal of the Korea Contents Association
    • /
    • v.16 no.10
    • /
    • pp.514-521
    • /
    • 2016
  • The High Efficiency Video Coding (HEVC) standard provides superior coding efficiency by utilizing highly flexible block structure and more diverse coding modes. However, rate-distortion optimization (RDO) process for the decision of optimal block size and prediction mode requires excessive computational complexity. To alleviate the computation load, this paper proposes a new moment-based fast CU size decision algorithm for intra coding in HEVC. In the proposed method, moment values are computed in each CU block to estimate the texture complexity of the block from which the decision on an additional CU splitting procedure is performed. Unlike conventional methods which are mostly variance-based approaches, the proposed method incorporates the third-order moments of the CU block in the design of the fast CU size decision algorithm, which enables an elaborate classification of CU types and thus improves the RD-performance of the fast algorithm. Experimental results show that the proposed method saves 32% encoding time with 1.1% increase of BD-rate compared to HM-10.0, and 4.2% decrease of BD-rate compared to the conventional variance-based fast algorithm.