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2008 IEEE International Conference on Industrial Technology, Pages 1-434

作者： Ximing Cheng Bingheng Mou Tongquan Shen Zhifu Wang School of Mechanical & Vehicular Engineering Beijing Institute of Technology Zhongguancun South Str. 5 BEIJING 100081 CHINA

ISBN: (纸本)9781424417056;9781424417063

The speed - voltage transfer function of the three - phase AC magnetic synchronous generator was directly identified through least-squares algorithm and instrumental variable technique from step responses. It was expressed as a second order plus dead time (SOPDT) continuous system. And the speed-voltage PID controller was designed and implemented on the internal model control (IMC) theory. Numerical simulation was done on Matlab/simulink, and dynamic experiments were tested on the 16bit micro-controller. Results were identical, which validates the identified model and designed control algorithm.

关键词： Synchronous generators Step response voltage transfer function computer algorithms instrumental variable technique Identical Magnetic force Microcontrollers internal model control continuous systems Proportional Integral Derivative Control DEAD TIME

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Development of Vision-based Autonomous Robotic Fish and Its Application in Water-polo-attacking Task

Development of Vision-based Autonomous Robotic Fish and Its ...

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2008 American Control Conference, Pages 441-879

作者： Wei Zhao Yonghui Hu Guangming Xie Long Wang Yingmin Jia Intelligent Control Laboratory Department of Mechanics and Space Technologies College of Engineering Peking University Beijing 100871 China

ISBN: (纸本)9781424420780

This paper presents the design and locomotion control of a vision-based autonomous robotic fish, and its application in water-polo-attacking task. Most of previous work on task strategies of autonomous robots is focused on the terrestrial robots and seldom deals with underwater applications. In fact, the tasks in underwater environment are more challenging than those in ground circumstances due to the uncertainties and complexity in hydro-environment. In this paper, a water-polo-attacking task is designed and implemented based on artificial potential field. The experimental results are presented to verify the effectiveness of the proposed control algorithms.

关键词： computer algorithms Wet underwater environment Autonomous robots Fishes potential field UNDERWATER APPLICATION

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Diabetes and the Tortuosity of Vessels of the Bulbar Conjunctiva

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Ophthalmology 2008年第6期115卷 e27-e32页

作者： Owen, Christopher G. Newsom, Richard S.B. Rudnicka, Alicja R. Barman, Sarah A. Woodward, E. Geoffrey Ellis, Tim J. Division of Community Health Sciences St. George's University of London London United Kingdom Southampton Eye Unit Southampton United Kingdom School of Computing Information Systems and Mathematics Kingston University Kingston-upon-Thames Surrey United Kingdom Department of Optometry and Visual Science City University London United Kingdom

Objectives: Diabetes is associated with loss of capillaries and macrovessel dilation in the conjunctiva, similar to well-known vessel changes in the retina. However, little is known about the effect of diabetes on the tortuosity of vessels of the conjunctiva. The authors examined the tortuosity of conjunctival vessels in participants with and without diabetes. Design: Case-control study. Participants and Controls: Fifty-three patients with diabetes (17 with type 1 diabetes, 36 with type 2 diabetes) and 60 controls (all aged 20-94 years). Methods: Digital red-free images of conjunctivae were analyzed using an automated computer algorithm to identify vessel axes and to quantify vessel tortuosity. Differences in vessel tortuosity were adjusted for age, gender, blood pressure, and smoking status. Main Outcome Measures: Tortuosity was expressed in units of curve energy (the square of the radian angular change between subsequent locations identified by the algorithm, standardized by vessel length). Results: A longer duration of diabetes was associated with a reduction in overall vessel tortuosity (-2.8%;95% confidence interval [CI], -4.3% to -1.3% per decade). This inverse association was driven by changes in larger vessels (40 μm in width or more), whereas increased tortuosity was observed in capillary sized vessels (<25 μm, 4.0%;95% CI, -0.2% to 8.2% per decade). Compared with controls, those with type 1 diabetes (median duration of disease, 26 years) showed a 17.9% increase (95% CI, 4.7% to -31.0%) in capillary tortuosity. Conversely, those with type 1 diabetes showed a 7% decrease (95% CI, -11.8% to -2.3%) in tortuosity among vessels 40 to 80 μm or less in size and a 26.8% decrease (95% CI, -66.2% to 12.7%) in the fewer number of vessels more than 80 μm in size compared with controls. Similar, but smaller differences were seen in those with type 2 diabetes with shorter duration of diabetes (median, 7 years). Conclusions: Macrovessel dilation associated with diabetes m

关键词： DIABETES CONJUNCTIVA SMOKING computer algorithms

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Local Independent Control of Cognitive Radio Networks

Local Independent Control of Cognitive Radio Networks

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3rd International Conference on Cognitive Radio Oriented Wireless Networks and Communications (CrownCom 2008)

作者： Christian Doerr Dirk Grunwald Douglas C. Sicker Department of Computer Science University of Colorado Boulder CO USA

ISBN: (纸本)9781424423019

Many different algorithms for managing cognitive radio networks have been proposed. While these algorithms have applied the whole range from centrally managed to distributed control schemes, a common feature of previous work is the reliance on explicit communication to exchange and negotiate configuration information. This paper describes a new class of cognitive radio control algorithms employing local independent control based upon swarming behavior found in nature. We examine the feasibility of such local independent control in a testbed implementation of the algorithm, configuring and dynamically adapting a cognitive radio network. We find that approach is suited to coordinate a cognitive radio network based on passive observation of its environment only and may coordinate with other control algorithms deployed in heterogeneous secondary user networks.

关键词： Cognitive radio Radio networks independent control computer algorithms Swarming behavior algorithms FULL-SCALE Reliance resin cement New classes Online resources

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Data Center Transport Mechanisms: Congestion Control Theory and IEEE Standardization

Data Center Transport Mechanisms: Congestion Control Theory ...

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Annual Allerton Conference on Communication, Control, and Computing

作者： Mohammad Alizadeh Berk Atikoglu Abdul Kabbani Ashvin Lakshmikantha Rong Pan Balaji Prabhakar Mick Seaman Department of Electrical Engineering Stanford University Department of Computer Science Stanford University Broadcom Corporation San Jose Cisco Systems San Jose Departments of Electrical Engineering and Computer Science Stanford University Security Task Group

ISBN: (纸本)9781424429257

Data Center Networks present a novel, unique and rich environment for algorithm development and deployment. Projects are underway in the IEEE 802.1 standards body, especially in the Data Center Bridging Task Group, to define new switched Ethernet functions for data center use. One such project is IEEE 802.1Qau, the Congestion Notification project, whose aim is to develop an Ethernet congestion control algorithm for hardware implementation. A major contribution of this paper is the description and analysis of the congestion control algorithm-QCN, for Quantized Congestion Notification - which has been developed for this purpose. A second contribution of the paper is an articulation of the Averaging Principle: a simple method for making congestion control loops stable in the face of increasing lags. This contrasts with two well-known methods of stabilizing control loops as lags increase;namely, (i) increasing the order of the system by sensing and feeding back higher-order derivatives of the state, and (ii) determining the lag and then choosing appropriate loop gains. Both methods have been applied in the congestion control literature to obtain stable algorithms for high bandwidth-delay product paths in the Internet. However, these methods are either undesirable or infeasible in the Ethernet context The Averaging Principle provides a simple alternative, one which we are able to theoretically characterize.

关键词： data center control ring INSTITUTE OF ELECTRICAL AND ELECTRONIC ENGINEERS Instruction repertory computer algorithms Joints Control Theory Ethernet networks notification closed-loop gain

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Efficient exploration of faulty trees

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THEORY OF COMPUTING SYSTEMS 2007年第3期40卷 225-247页

作者： Markou, Euripides Pelc, Andrzej Univ Quebec Dept Informat Gatineau PQ J8X 3X7 Canada

We consider the problem of the exploration of trees, some of whose edges are faulty. A robot, situated in a starting node and unaware of the location of faults, has to explore the connected fault-free component of this node by visiting all its nodes. The cost of the exploration is the number of edge traversals. For a given tree and given starting node, the overhead of an exploration algorithm is the worst-case ratio (taken over all fault configurations) of its cost to the cost of an optimal algorithm which knows where faults are situated. An algorithm, for a given tree and given starting node, is called perfectly competitive if its overhead is the smallest among all exploration algorithms not knowing the location of faults. We design a perfectly competitive exploration algorithm for any line, and an exploration algorithm for any tree, whose overhead is at most 9/8 larger than that of a perfectly competitive algorithm. Both our algorithms are fairly natural and the total time of local computations used during exploration is linear in the size of the explored tree. Our main contribution is the analysis of the performance of these algorithms, showing that natural exploration strategies perform well in faulty trees.

关键词： algorithms ROBOTICS computer programming computer algorithms MOBILE agents (computer software)

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Conformal thermal therapy using planar ultrasound transducers and adaptive closed-loop MR temperature control:: demonstration in gel phantoms and ex vivo tissues

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PHYSICS IN MEDICINE AND BIOLOGY 2007年第10期52卷 2905-2919页

作者： Tang, K. Choy, V. Chopra, R. Bronskill, M. J. Sunnybrook Hlth Sci Ctr Toronto ON M4N 3M5 Canada Univ Toronto Dept Med Biophys Toronto ON Canada

MRI-guided transurethral ultrasound therapy offers a minimally invasive approach for the treatment of localized prostate cancer. Integrating a multi-element planar transducer with active MR temperature feedback can enable three-dimensional conformal thermal therapy of a target region within the prostate gland while sparing surrounding normal tissues. Continuous measurement of the temperature distribution in tissue enables dynamic compensation for unknown changes in blood flow and tissue properties during treatment. The main goal of this study was to evaluate the feasibility of using active temperature feedback on a clinical 1.5 T MR imager for conformal thermal therapy. MR thermometry was performed during heating in both gel phantoms and excised tissue with a transurethral heating applicator, and the rotation rate and power were varied based on the thermal measurements. The capability to produce a region of thermal damage that matched a target boundary was evaluated. The influence of a cooling gradient ( to simulate cooling of the rectum or urethra) on the desired pattern of thermal damage was also investigated in gel phantoms. Results showed high correlation between the desired target boundary and the 55. C isotherm generated during heating with an average distance error of 0.9 mm +/- 0.4 mm (n = 6) in turkey breasts, 1.4 mm +/- 0.6 mm (n = 4) in gel phantoms without rectal cooling and 1.4 mm +/- 0.6 mm (n = 3) in gel phantoms with rectal cooling. The results were obtained using a temporal update rate of 5 s, a spatial resolution of 3 x 3 x 10 mm for the control point, and a temperature uncertainty of approximately 1 degrees C. The performance of the control algorithm under these conditions was comparable to that of simulations conducted previously by our group. Overall, the feasibility of generating targeted regions of thermal damage with a transurethral heating applicator and active MR temperature feedback has been demonstrated experimentally. This method of trea

关键词： Prostate Mm control point Temperature distribution Blood Flow computer algorithms EX-VIVO Heating Gels temperature feedback conformal Thermal techniques Blood Circulation

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Optimal semi-online algorithms for preemptive scheduling problems with inexact partial information

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ACTA INFORMATICA 2007年第7-8期44卷 571-590页

作者： Jiang, Yiwei He, Yong Zhejiang Sci Tech Univ Fac Sci Key Lab Adv Text Mat & Mfg Technol Hangzhou 310018 Peoples R China Zhejiang Univ Dept Math Hangzhou 310027 Peoples R China

In semi-online scheduling problems, we always assume that some partial additional information is exactly known in advance. This may not be true in some application. This paper considers semi-online problems on identical machines with inexact partial information. Three problems are considered, where we know in advance that the optimal value, or the largest job size are in given intervals, respectively, while their exact values are unknown. We give both lower bounds of the problems and competitive ratios of algorithms as functions of a so-called disturbance parameter r is an element of [1, infinity). We establish for which r the inexact partial information is useful to improve the performance of a semi-online algorithm with respect to its pure online problem. Optimal preemptive semi-online algorithms are then obtained.

关键词： computer science -- Mathematics computer algorithms computer scheduling ONLINE data processing algorithms

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Exploratory data analysis with categorical variables: An improved rank-by-feature framework and a case study

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INTERNATIONAL JOURNAL OF HUMAN-computer INTERACTION 2007年第3期23卷 287-314页

作者： Seo, Jinwook Gordish-Dressman, Heather Childrens Res Inst Res Ctr Genet Med Washington DC 20010 USA

Multidimensional data sets often include categorical information. When most dimensions have categorical information, clustering the data set as a whole can reveal interesting patterns in the data set. However, the categorical information is often more useful as a way to partition the data set: gene expression data for healthy versus diseased samples or stock performance for common, preferred, or convertible shares. We present novel ways to utilize categorical information in exploratory data analysis by enhancing the rank-by-feature framework. First, we present ranking criteria for categorical variables and ways to improve the score overview. Second, we present a novel way to utilize the categorical information together with clustering algorithms. Users can partition the data set according to categorical information vertically or horizontally, and the clustering result for each partition can serve as new categorical information. We report the results of a longitudinal case study with a biomedical research team, including insights gained and potential future work.

关键词： Information storage & retrieval systems Management information systems Database management Information services Information processing computer algorithms computer programming Multidimensional databases Medical research

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Executable cell biology

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NATURE BIOTECHNOLOGY 2007年第11期25卷 1239-1249页

作者： Fisher, Jasmin Henzinger, Thomas A. Microsoft Res Cambridge CB3 0FB England Ecole Polytech Fed Lausanne Sch Comp & Commun Sci CH-1015 Lausanne Switzerland Univ Calif Berkeley Dept Elect Engn & Comp Sci Berkeley CA 94720 USA

Computational modeling of biological systems is becoming increasingly important in efforts to better understand complex biological behaviors. In this review, we distinguish between two types of biological models-mathematical and computational which differ in their representations of biological phenomena. We call the approach of constructing computational models of biological systems 'executable biology', as it focuses on the design of executable computer algorithms that mimic biological phenomena. We survey the main modeling efforts in this direction, emphasize the applicability and benefits of executable models in biological research and highlight some of the challenges that executable biology poses for biology and computer science. We claim that for executable biology to reach its full potential as a mainstream biological technique, formal and algorithmic approaches must be integrated into biological research. This will drive biology toward a more precise engineering discipline.

关键词： CYTOLOGY CELLS BIOLOGICAL models BIOLOGICAL research LIFE sciences computer science SYSTEMS theory computer algorithms MATHEMATICAL models

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