CAS Shenyang Institute of Computing Technology

Shenyang, China

CAS Shenyang Institute of Computing Technology

Shenyang, China
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Zhang X.,Shanghai Sany Precision Machinery Co. | Zhang X.,CAS Shenyang Institute of Computing Technology | Yu D.,CAS Shenyang Institute of Computing Technology | Song T.,CAS Shenyang Institute of Computing Technology
International Journal of Advanced Manufacturing Technology | Year: 2012

The existing interpolation algorithm cannot meet the need of high-speed and high-accuracy machining of a free-form surface. So this paper proposed a correcting and compressing interpolation algorithm. Depending on the distance and angle evaluated from the adjacent command points, the machining path of free form can be divided into two machining types. For those regions where the accurate figure is critical such as corners, the convention linear interpolation is performed exactly between the adjacent command points. For those regions having a large radius of curvature where the smooth figure is critical, firstly, the interior point selection method based on circle transition is derived to reduce the tolerance between the machining path and the original surface; secondly, the interior point correction method based on the least-square method is proposed to reduce the calculation error and round-off error in the interior point and estimate the first- and second-order derivative vectors of the interior point; thirdly, the shape-defining point is selected by the bend direction of the machining path and fitted to a quintic spline curve which has the C2 continuity; fourthly, the fitting accuracy controlling method is proposed to ensure the machining accuracy; lastly, the curve interpolation is performed on the fitted smooth curve. Machining tests carried out on a vertical machining center show that the proposed algorithm can improve the machining efficiency and machining quality of a free-form surface. © Springer-Verlag London Limited 2012.


Hui C.,Shenyang University | Chao H.H.,CAS Shenyang Institute of Computing Technology
Proceedings of the 2nd International Conference on Electronic and Mechanical Engineering and Information Technology, EMEIT 2012 | Year: 2012

To monitor Session Initiation protocol (SIP) traffic effectively, a statistical approaches-based traffic monitoring solution is proposed in this paper. According to the process of SIP session, Chi-square statistic is used for monitoring the anomaly of SIP traffic. It classifies the anomaly reason using entropy theory. SIP packets are captured utilizing the kernel SIP packet filtering technology. Experimental result shows that this solution of SIP traffic monitoring is feasible and effective. © the authors.


Lin H.,CAS Shenyang Institute of Computing Technology | Peng Y.,CAS Shenyang Institute of Computing Technology | Peng Y.,University of Chinese Academy of Sciences
Kongzhi Lilun Yu Yingyong/Control Theory and Applications | Year: 2011

The purpose of the multi-objective optimization is to quickly find out the Pareto optimal solutions which converge to the ideal Pareto front with a good performance in diversity. Based on the immune clonal theory, this paper introduces the fitness sharing strategy; and then a new multi-objective optimization evolutionary algorithm with good performance in diversity is proposed for maintaining the diversity of solutions. The proposed algorithm employs an external archive to preserve the non-dominated solutions. The principle which includes sharing fitness and Pareto domination is used to update the external archive mentioned above and select the active antibodies for generating offspring. Moreover, for enhancing the search ability in the decision space, this paper introduces the good-point-searching approach which can generate the good-point set with uniform distribution. The proposed algorithm is tested on several multi-objective optimization problems and compared with many classical methods; much better performances in both the convergence and diversity of obtained solutions are observed.


Li J.,Hefei University of Technology | Guo R.,CAS Shenyang Institute of Computing Technology | Zhang X.,Hefei University of Technology
Proceedings - 2010 3rd IEEE International Conference on Computer Science and Information Technology, ICCSIT 2010 | Year: 2010

Cloud computing, a new thing which is only three years old, becomes the most fashionable technology and developing trend in IT industry now. People say "X as a service" in the cloud computing, which means that everything including software and hardware can be taken as a service for consumers in the cloud. Meanwhile, a high quality multimedia conferencing has been an urgent requirement these years. The products in the market are immature. They can't support very large number of participants and multiple HD video in a meeting. In this paper, we consider conference as a service, and propose a feasible framework of multimedia conferencing in cloud. As it follows the structure of SOA, we name it Service-Oriented Cloud Conferencing. We then present the software structure and flow procedures. We prove that the cloud conferencing overcomes the deficiencies of existing products with the support of excellent characteristics of cloud. © 2010 IEEE.


Wang Y.,CAS Shenyang Institute of Computing Technology | Wang Y.,University of Chinese Academy of Sciences | Yang D.,CAS Shenyang Institute of Computing Technology | Liu Y.,CAS Shenyang Institute of Computing Technology
International Journal of Machine Tools and Manufacture | Year: 2014

To process the complex geometric-shapes consisting of discrete data points, this paper presents a real-time look-ahead interpolation algorithm based on Akima curve fitting. The algorithm consists of two modules: pretreatment module and real-time interpolation module. The pretreatment module firstly adopts the bi-chord and tangent-chord criteria to identify those continuous Akima blocks and calculates the linking velocity between two adjacent blocks according to the required machining accuracy. Then the five-point Akima method is used to fit the continuous blocks into a Akima spline curve. In the real-time interpolation module, the look-ahead interpolation is executed to ensure that the processing error is limited in a satisfying range, and the Newton iteration method is employed to calculate the parameters when interpolating Akima spline blocks. Simulations and experimental results demonstrate that the Akima spline is more suitable when processing discrete data points. And the proposed look-ahead interpolation algorithm could reduce the feedrate fluctuation to satisfactory level and implement high-quality CNC processing. © 2014 Elsevier Ltd.


Zhang Y.-W.,CAS Shenyang Institute of Computing Technology | Zhang Y.-W.,University of Chinese Academy of Sciences | Guo R.-F.,CAS Shenyang Institute of Computing Technology
Journal of Systems and Software | Year: 2013

In this paper, we consider the canonical sporadic task model with the system-wide energy management problem. Our solution uses a generalized power model, in which the static power and the dynamic power are considered. We present a static solution to schedule the sporadic task set, assuming worst-case execution time for each sporadic tasks release, and propose a dynamic solution to reclaim the slacks left by the earlier completion of tasks than their worst-case estimations. The experimental results show that the proposed static algorithm can reduce the energy consumption by 20.63%-89.70% over the EDF* algorithm and the dynamic algorithm consumes 2.06%-24.89% less energy than that of the existing DVS algorithm. © 2013 Elsevier Inc.


Jie L.,University of Chinese Academy of Sciences | Ruifeng G.,CAS Shenyang Institute of Computing Technology | Zhixiang S.,University of Chinese Academy of Sciences
CCTAE 2010 - 2010 International Conference on Computer and Communication Technologies in Agriculture Engineering | Year: 2010

Scheduling algorithm is a hot research topic of real-time system. The quality of real-time scheduling algorithm has a direct impact on real-time system's throughput capacity, response time, even on tasks' scheduling result in required deadline. This paper discusses the features and performance of real-time system. According to system environment, real-time system can be divided into uniprocessor scheduling, centralized multiprocessor scheduling and distributed scheduling. Classic real-time scheduling algorithms RMS, EDF and LLF are discussed in uniprocessor systems. The scheduling thought and strategies are investigated in multiprocessor systems. Distributed real-time scheduling algorithms such as GRMS and DSr are analyzed briefly. Finally, it points out the future direction of real-time scheduling research. © 2010 IEEE.


San H.,Shenyang University of Technology | Fei J.,CAS Shenyang Institute of Computing Technology
Procedia Engineering | Year: 2012

The generation of the driving schedules of CCD is the key of the application of CCD. Based on SCM a practical design of TCD1208AP driving circuit and its schedules simulation were given. The hardware circuit is simple and reliable. © 2011 Published by Elsevier Ltd.


Zhang Y.,Jining University | Li P.,Jining University | Wu W.-J.,CAS Shenyang Institute of Computing Technology
Procedia Engineering | Year: 2012

Considering changes, strong interference of load torque and moment of inertia for alternating current position servo system, a single neuron PID and sliding mode parallel compound control strategy is proposed. The parallel architecture that consists of a sliding mode variable structure controller of the position loop and the single neuron PID controller is designed. Sliding mode control inhibits the parameter perturbations and load disturbance, single neuron PID control realizes the online adjustments of the proportional, integral, differential parameters of traditional PID controller. The simulation results show that the designed parallel compound controller can guarantee static and dynamic system performance. © 2011 Published by Elsevier Ltd.


Zhang Y.-W.,CAS Shenyang Institute of Computing Technology | Zhang Y.-W.,University of Chinese Academy of Sciences | Guo R.-F.,University of Chinese Academy of Sciences
Journal of Systems and Software | Year: 2014

In this paper, we consider the generalized power model in which the focus is the dynamic power and the static power, and we study the problem of the canonical sporadic task scheduling based on the rate-monotonic (RM) scheme. Moreover, we combine with the dynamic voltage scaling (DVS) and dynamic power management (DPM). We present a static low power sporadic tasks scheduling algorithm (SSTLPSA), assuming that each task presents its worst-case work-load to the processor at every instance. In addition, a more energy efficient approach called a dynamic low power sporadic tasks scheduling algorithm (DSTLPSA) is proposed, based on reclaiming the dynamic slack and adjusting the speed of other tasks on-the-fly in order to reduce energy consumption while still meeting the deadlines. The experimental results show that the SSTLPSA algorithm consumes 26.55-38.67% less energy than that of the RM algorithm and the DSTLPSA algorithm reduces the energy consumption up to 18.38-30.51% over the existing DVS algorithm. © 2014 Elsevier Inc.

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