Loading...

Current Issue

, Volume 9 Issue 8 Previous Issue    Next Issue
Electrical & Electronic Engineering
A new neural network model for the feedback stabilization of nonlinear systems
Mei-qin LIU, Sen-lin ZHANG, Gang-feng YAN
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1015-1023.   https://doi.org/10.1631/jzus.A0720122
Abstract( 2429 )     PDF(0KB)( 1890 )
A new neural network model termed ‘standard neural network model’ (SNNM) is presented, and a state-feedback control law is then designed for the SNNM to stabilize the closed-loop system. The control design constraints are shown to be a set of linear matrix inequalities (LMIs), which can be easily solved by the MATLAB LMI Control Toolbox to determine the control law. Most recurrent neural networks (including the chaotic neural network) and nonlinear systems modeled by neural networks or Takagi and Sugeno (T-S) fuzzy models can be transformed into the SNNMs to be stabilization controllers synthesized in the framework of a unified SNNM. Finally, three numerical examples are provided to illustrate the design developed in this paper.
Suboptimal reliable guaranteed cost control for continuous-time systems with multi-criterion constraints
Deng-feng ZHANG, Hong-ye SU, Jian CHU, Zhi-quan WANG
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1024-1033.   https://doi.org/10.1631/jzus.A0720031
Abstract( 2323 )     PDF(0KB)( 1436 )
The suboptimal reliable guaranteed cost control (RGCC) with multi-criterion constraints is investigated for a class of uncertain continuous-time systems with sensor faults. A fault model in sensors, which considers outage or partial degradation of sensors, is adopted. The influence of the disturbance on the quadratic stability of the closed-loop systems is analyzed. The reliable state-feedback controller is developed by a linear matrix inequalities (LMIs) approach, to minimize the upper bound of a quadratic cost function under the conditions that all the closed-loop poles be placed in a specified disk, and that the prescribed level of H disturbance attenuation and the upper bound constraints of control inputs’ magnitudes be guaranteed. Thus, with the above multi-criterion constraints, the resulting closed-loop system can provide satisfactory stability, transient property, a disturbance rejection level and minimized quadratic cost performance despite possible sensor faults.
Delay-dependent robust control for uncertain discrete singular systems with time-varying delay
Hui-jiao WANG, Xiao-dong ZHAO, An-ke XUE, Ren-quan LU
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1034-1042.   https://doi.org/10.1631/jzus.A0720008
Abstract( 2485 )     PDF(0KB)( 1792 )
The design problem of delay-dependent robust control for uncertain discrete singular systems with time-varying delay is addressed in this paper. The uncertainty is assumed to be norm-bounded. By establishing a finite sum inequality based on quadratic terms, a new delay-dependent robust stability condition is derived and expressed in terms of linear matrix inequalities (LMIs). A suitable robust state feedback control law is presented, which guarantees that the resultant closed-loop system is regular, causal and stable for all admissible uncertainties. Numerical examples are given to demonstrate the applicability of the proposed method.
Dynamical output feedback stabilization for neutral systems with mixed delays
Wei QIAN, Guo-jiang SHEN, You-xian SUN
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1043-1049.   https://doi.org/10.1631/jzus.A0720044
Abstract( 2172 )     PDF(0KB)( 1301 )
This paper is concerned with the issue of stabilization for the linear neutral systems with mixed delays. The attention is focused on the design of output feedback controllers which guarantee the asymptotical stability of the closed-loop systems. Based on the model transformation of neutral type, the Lyapunov-Krasovskii functional method is employed to establish the delay-dependent stability criterion. Then, through the controller parameterization and some matrix transformation techniques, the desired parameters are determined under the delay-dependent design condition in terms of linear matrix inequalities (LMIs), and the desired controller is explicitly formulated. A numerical example is given to illustrate the effectiveness of the proposed method.
A closed-loop particle swarm optimizer for multivariable process controller design
Kai HAN, Jun ZHAO, Zu-hua XU, Ji-xin QIAN
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1050-1060.   https://doi.org/10.1631/jzus.A0720081
Abstract( 2287 )     PDF(0KB)( 2594 )
Design of general multivariable process controllers is an attractive and practical alternative to optimizing design by evolutionary algorithms (EAs) since it can be formulated as an optimization problem. A closed-loop particle swarm optimization (CLPSO) algorithm is proposed by mapping PSO elements into the closed-loop system based on control theories. At each time step, a proportional integral (PI) controller is used to calculate an updated inertia weight for each particle in swarms from its last fitness. With this modification, limitations caused by a uniform inertia weight for the whole population are avoided, and the particles have enough diversity. After the effectiveness, efficiency and robustness are tested by benchmark functions, CLPSO is applied to design a multivariable proportional-integral-derivative (PID) controller for a solvent dehydration tower in a chemical plant and has improved its performances.
Batch process monitoring based on multilevel ICA-PCA
Zhi-qiang GE, Zhi-huan SONG
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1061-1069.   https://doi.org/10.1631/jzus.A0720051
Abstract( 2370 )     PDF(0KB)( 1913 )
In this paper, we describe a new batch process monitoring method based on multilevel independent component analysis and principal component analysis (MLICA-PCA). Unlike the conventional multi-way principal component analysis (MPCA) method, MLICA-PCA provides a separated interpretation for multilevel batch process data. Batch process data are partitioned into two levels: the within-batch level and the between-batch level. In each level, the Gaussian and non-Gaussian components of process information can be separately extracted. I2, T2 and SPE statistics are individually built and monitored. The new method facilitates fault diagnosis. Since the two variation levels are decomposed, the variables responsible for faults in each level can be identified and interpreted more easily. A case study of the Dupont benchmark process showed that the proposed method was more efficient and interpretable in fault detection and diagnosis, compared to the alternative batch process monitoring method.
A spatially triggered dissipative resource distribution policy for SMT processors
Hong-zhou CHEN, Xue-zeng PAN, Ling-di PING, Kui-jun LU, Xiao-ping CHEN
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1070-1082.   https://doi.org/10.1631/jzus.A0720083
Abstract( 2477 )     PDF(0KB)( 1574 )
Programs take on changing behavior at runtime in a simultaneous multithreading (SMT) environment. How reasonably common resources are distributed among the threads significantly determines the throughput and fairness performance in SMT processors. Existing resource distribution methods either mainly rely on the front-end fetch policy, or make distribution decisions according to the limited information from the pipeline. It is difficult for them to efficiently catch the various resource requirements of the threads. This work presents a spatially triggered dissipative resource distribution (SDRD) policy for SMT processors. Its two parts, the self-organization mechanism that is driven by the real-time instructions per cycle (IPC) performance and the introduction of chaos that tries to control the diversity of trial resource distributions, work together to supply sustaining resource distribution optimization for changing program behavior. Simulation results show that SDRD with fine-grained diversity controlling is more effective than that with a coarse-grained one. And SDRD benefits much from its two well-coordinated parts, providing potential fairness gains as well as good throughput gains. Meanings and settings of important SDRD parameters are also discussed.
AS/RS based yard and yard planning
Ya-hong HU, Zheng-dong ZHU, Wen-jing HSU
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1083-1089.   https://doi.org/10.1631/jzus.A071522
Abstract( 2267 )     PDF(0KB)( 1585 )
In this paper, we apply the split-platform automated storage/retrieval systems (SP-AS/RSs) (Hu et al., 2005) to store containers in the yard to improve the yard performance and to increase the utilization of the yard space. The layout of an SP-AS/RS based yard is described in detail. To achieve an efficient operation, we present a novel yard space allocation policy called the ‘second-carrier-based allocation policy’, which can help to alleviate the out-of-sequence problem of containers and the congestion of vehicles at the AS/RS racks. Different allocation policies are compared by an integrated container terminal simulation system. The simulation results show that the second-carrier-based policy is very efficient and has the potential to offer high terminal performance.
Enhanced cooperative packet retransmission employing joint cooperative diversity and symbol mapping diversity
Wei JI, Bao-yu ZHENG
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1090-1098.   https://doi.org/10.1631/jzus.A0720076
Abstract( 2645 )     PDF(0KB)( 1571 )
A joint cooperation diversity and symbol mapping diversity (SMD) strategy is proposed for cooperative packet retransmission system with high-order modulation such as 16QAM. Substantial SER/BER (symbol error rate/bit error rate) gains result from multiple packet transmissions over independent paths and distinct bit-to-symbol mappings for each packet transmission. The SER/BER performance of relay assisted retransmission system is analyzed. Simulation results show that the joint-diversity strategy can provide more BER gains than other relaying strategies (i.e., decode-and-forward and constellation rearrangement relaying strategies) when no relay makes a decision error; but if some relays make decision errors, the joint-diversity strategy outperforms other relaying strategies only when the relays are closer to the source than to the destination.
Reliable energy-efficient routing with novel route update in wireless sensor networks
R. VIDHYAPRIYA, P. T. VANATHI
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1099-1110.   https://doi.org/10.1631/jzus.A072260
Abstract( 2681 )     PDF(0KB)( 1751 )
In this paper we introduce a novel energy-aware routing protocol REPU (reliable, efficient with path update), which provides reliability and energy efficiency in data delivery. REPU utilizes the residual energy available in the nodes and the received signal strength of the nodes to identify the best possible route to the destination. Reliability is achieved by selecting a number of intermediate nodes as waypoints and the route is divided into smaller segments by the waypoints. One distinct advantage of this model is that when a node on the route moves out or fails, instead of discarding the whole original route, only the two waypoint nodes of the broken segment are used to find a new path. REPU outperforms traditional schemes by establishing an energy-efficient path and also takes care of efficient route maintenance. Simulation results show that this routing scheme achieves much higher performance than the classical routing protocols, even in the presence of high node density, and overcomes simultaneous packet forwarding.
Improved Feistel-based ciphers for wireless sensor network security
Tamara PAZYNYUK, Jian-zhong LI, George S. OREKU
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1111-1117.   https://doi.org/10.1631/jzus.A0720108
Abstract( 2980 )     PDF(0KB)( 3633 )
Wireless sensor networks (WSNs) are exposed to a variety of attacks. The quality and complexity of attacks are rising day by day. The proposed work aims at showing how the complexity of modern attacks is growing accordingly, leading to a similar rise in methods of resistance. Limitations in computational and battery power in sensor nodes are constraints on the diversity of security mechanisms. We must apply only suitable mechanisms to WSN where our approach was motivated by the application of an improved Feistel scheme. The modified accelerated-cipher design uses data-dependent permutations, and can be used for fast hardware, firmware, software and WSN encryption systems. The approach presented showed that ciphers using this approach are less likely to suffer intrusion of differential cryptanalysis than currently used popular WSN ciphers like DES, Camellia and so on.
Cryptanalysis of an image encryption scheme based on the Hill cipher
Cheng-qing LI, Dan ZHANG, Guan-rong CHEN
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1118-1123.   https://doi.org/10.1631/jzus.A0720102
Abstract( 2313 )     PDF(0KB)( 1700 )
This paper studies the security of an image encryption scheme based on the Hill cipher (Ismail et al., 2006) and reports its following problems: (1) There is a simple necessary and sufficient condition that makes a number of secret keys invalid; (2) It is insensitive to the change of the secret key; (3) It is insensitive to the change of the plain-image; (4) It can be broken with only one known/chosen plaintext; (5) It has some other minor defects. The proposed cryptanalysis discourages any use of the scheme in practice.
ε-inclusion: privacy preserving re-publication of dynamic datasets
Qiong WEI, Yan-sheng LU, Lei ZOU
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1124-1133.   https://doi.org/10.1631/jzus.A071595
Abstract( 2249 )     PDF(0KB)( 1226 )
This paper presents a novel privacy principle, ε-inclusion, for re-publishing sensitive dynamic datasets. ε-inclusion releases all the quasi-identifier values directly and uses permutation-based method and substitution to anonymize the microdata. Combined with generalization-based methods, ε-inclusion protects privacy and captures a large amount of correlation in the microdata. We develop an effective algorithm for computing anonymized tables that obey the ε-inclusion privacy requirement. Extensive experiments confirm that our solution allows significantly more effective data analysis than generalization-based methods.
Applying sub-band energy extraction to noise cancellation of ultrasonic NDT signal
Qi ZHANG, Pei-wen QUE, Wei LIANG
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1134-1140.   https://doi.org/10.1631/jzus.A0720072
Abstract( 2443 )     PDF(0KB)( 1515 )
In ultrasonic non-destructive tests, the echo signal at the flaw is highly complex due to the interference of multiple echoes with random amplitudes and phases, and is disturbed by all kinds of noises, such as thermal noise, digitalization noise, and structure noise. In this paper, the ultrasonic signal was decomposed by empirical mode decomposition (EMD) to obtain the intrinsic mode function (IMF) components according to ultrasonic defect echo signals occuring at the corresponding time, and the energy of the ultrasonic signal was concentrated. The IMF component selection criterion based on sub-band energy extraction was proposed to extract the ultrasonic signal component accurately and automatically from IMF components. When the selected IMF components were filtered by a band pass filter, the signal-to-noise ratio (SNR) was enhanced greatly.
Development of a non-cable whole tectorial membrane micro-robot for an endoscope
Dong-dong YE, Guo-zheng YAN, Kun-dong WANG, Guan-ying MA
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1141-1149.   https://doi.org/10.1631/jzus.A0720074
Abstract( 2375 )     PDF(0KB)( 1618 )
A novel non-cable whole tectorial membrane micro-robot for an endoscope is developed. The micro-robot we have fabricated and tested can propel itself in the intestine tract of a pig in an autonomous manner by earthworm-like locomotion. The silicone of bellow shape is laid over the outer surface of the micro-robot to reduce the affection of the viscoelastic properties of the intestine. Wireless power transfer and communication systems are employed to realize the non-cable locomotion of the micro-robot. The prototype of the micro-robot is 13.5 mm in diameter and 108 mm in length. The experimental results show that the towing force for the micro-robot is about 0.8 N, which is much smaller than the maximum driving force 2.55 N of the linear actuator. The supplying power of the wireless power transfer system fulfills the needs of the micro-robot system and the micro-robot can creep reliably in the large intestine of a pig and other contact environments.
A novel current-sharing scheme based on magamp
Wen-xi YAO, Xiao-yuan HONG, Zheng-yu LU
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2008, 9(8): 1150-1156.   https://doi.org/10.1631/jzus.A0720112
Abstract( 2209 )     PDF(0KB)( 1688 )
The magamp (magnetic amplifier) is widely used in power supplies due to its low cost, simplicity and other advantages. This paper discusses a novel application of the magamp in switching power supplies, where the magamp is used to regulate pulse width modulation (PWM) instead of power signal in the main circuit. This method extends the application of the magamp in power supplies, and makes it possible to further regulate control signal when PWMs have been generated. Based on this application, a new current-sharing (CS) scheme using the magamp is proposed, which uses a modified inner loop CS structure. In this scheme PWMs are generated by one main controller, and CS is achieved by regulating PWMs using a magamp in each module. Compared with traditional application of the magamp, the new CS scheme can be used in most topologies and only requires magamps of low power capacity. Then a test circuit of parallel power supply is developed, in which CS is achieved by a PWM regulator with the magamp. The proposed scheme is also used to upgrade an electroplate power to make it capable of paralleling supplies. Experimental results show that the proposed scheme has good CS performance.
16 articles

NoticeMore

Links