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Efficient conditional tracepoints in kernel space

Open Cybernetics and Systemics Journal 2012年第1期6卷 11-25页

作者： Fahem, Rafik Dagenais, Michel Department of Computer and Software Engineering Ecole Polytechnique de Montreal P.O. Box 6079 Succ. Downtown Montreal QC H3C 3A7 Canada

With kernel static tracepoints, it is now possible to add instrumentation to the Linux kernel and obtain a low overhead trace of the whole system. However, these static tracepoints may be insufficient to diagnose the source of a functional or performance problem. Dynamic instrumentation fills the gap by enabling the insertion of additional tracepoints in other locations at run time. This article presents a new approach for tracing the Linux kernel with dynamic and static tracepoints. These tracepoints will be conditional. Conditions are defined using complex expressions that employ the code variables and make use of arithmetic and logic operations. These expressions are written using C-like syntax. Both static and dynamic tracepoints will evaluate and collect expressions similar to those used for conditions. In addition, static tracepoints will collect the static tracepoint data, as defined by the TRACE_EVENT macro used to define tracepoints in the Linux kernel. Our tool was implemented based on GDB and KGTP, which is a GDB stub in kernel-space that partially implements dynamic tracepoints. © Fahem and Dagenais.

关键词： Linux

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Towards MR-navigable nanorobotic carriers for drug delivery into the brain

Towards MR-navigable nanorobotic carriers for drug delivery ...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Seyed Nasrollah Tabatabaei Sonia Duchemin Helene Girouard Sylvain Martel Nanorobotics Laboratory École Polytechnique de Montréal QUE Canada Cerebrovascular Pharmacology Laboratory Department of Pharmacology Universite de Montreal Montreal QUE Canada Department of Pharmacology Cerebrovascular Pharmacology Laboratory Universite de Montreal Montreal QUE Canada Nanorobotics Laboratory Department of Computer and Software Engineering École Polytechnique de Montréal Centreville QUE Canada

Magnetic Resonance Navigation (MRN) relies on Magnetic Nanoparticles (MNPs) embedded in microcarriers or microrobots to allow the induction of a directional propelling force by 3-D magnetic gradients. These magnetic gradients are superposed on a sufficiently high homogeneous magnetic field (e.g. the Bo field of a MR scanner) to achieve maximum propelling force through magnetization saturation of the MNPs. As previously demonstrated by our group, such technique was successful at maintaining microcarriers along a planned trajectory in the blood vessels based on tracking information gathered using Magnetic Resonance Imaging (MRI) sequences from artifacts caused by the same MNPs. Besides propulsion and tracking, the same MNPs can be synthesized with characteristics that can allow for the diffusion of therapeutic cargo carried by these MR-navigable carriers through the Blood Brain Barrier (BBB) using localized hyperthermia without compromising the MRN capabilities. In the present study, localized hyperthermia induced by an alternating magnetic field (AC field) is investigated for the purpose of transient controlled disruption of the BBB and hence local delivery of therapeutic agents into the brain. Here, an external heating apparatus was used to impose a regional heat shock on the skull of a living mouse model. The effect of heat on the permeability of the BBB was assessed using histological observation and tissue staining by Evans blue dye. Results show direct correlation between hyperthermia and BBB leakage as well as its recovery from thermal damage. Therefore, in addition to on-command propulsion and remote tracking, the proposed navigable agents could be suitable for controlled opening of the BBB by hyperthermia and selective brain drug delivery.

关键词： Heating Magnetic resonance imaging Hyperthermia Saturation magnetization Nanoparticles Mice

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Magnetic propulsion of a spiral-type endoscopic microrobot in a real small intestine

Magnetic propulsion of a spiral-type endoscopic microrobot i...

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IEEE/ASME (AIM) International Conference on Advanced Intelligent Mechatronics

作者： Hao Zhou Gursel Alici Trung Duc Than Weihua Li Sylvain Martel School of Mechanical Materials and Mechatronic Engineering University of Wollongong New South Wales Australia School of Mechanical Materials and Mechatronic Engineering and ARC Centre of Excellence for Electromaterials Science University of Wollongong New South Wales Australia Department of Computer and Software Engineering and the Institute of Biomedical Engineering Polytechnique de Montréal University of Montréal Montreal Canada

This paper reports on the magnetic propulsion of a spiral-type endoscopic mircorobot in a real small intestine. Magnetic modeling was carried out to design and commission an external electromagnetic system, which wirelessly provides power to the robotic agent. The capsules with different spiral structures were magnetically propelled inside a segment of porcine small intestine. From the results, it is shown that the propulsive velocities of the tested capsules are in the range of 2.5 ~ 35 mm/s when rotating frequencies varying between 1 ~ 5 Hz are applied. Among all the capsules prepared for this study, the capsule No. 5, with one spiral and a helical angle of 20° and spiral height of 1 mm, shows the best performance. The effects of the spiral parameters, such as helical angle, number of spirals and spiral height, are evaluated by using the propulsion velocity and the slip ratio as the evaluation criteria.

关键词： Spirals Coils Magnetic fields Propulsion Magnetic flux Intestines Robots

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A Stateful Approach to Generate Synthetic Events from Kernel Traces

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Advances in software engineering 2012年第1期2012卷

作者： Naser Ezzati-Jivan Michel R. Dagenais Department of Computer and Software Engineering Ecole Polytechnique de Montreal C.P. 6079 Station Downtown Montreal Quebec Canada H3C 3A7polymtl.ca

We propose a generic synthetic event generator from kernel trace events. The proposed method makes use of patterns of system states and environment-independent semantic events rather than platform-specific raw events. This method can be applied to different kernel and user level trace formats. We use a state model to store intermediate states and events. This stateful method supports partial trace abstraction and enables users to seek and navigate through the trace events and to abstract out the desired part. Since it uses the current and previous values of the system states and has more knowledge of the underlying system execution, it can generate a wide range of synthetic events. One of the obvious applications of this method is the identification of system faults and problems that will appear later in this paper. We will discuss the architecture of the method, its implementation, and the performance results.

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Accurate positioning of magnetic microparticles beyond the spatial resolution of clinical MRI scanners using susceptibility artifacts

Accurate positioning of magnetic microparticles beyond the s...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society

作者： N. Olamaei F. Cheriet S. Martel Ecole Polytechnique Montreal Sainte-Justine Hospital Research Center and Ecole Polytechnique Montreal NanoRobotics Laboratory Department of Computer and Software Engineering and the Institute of Biomedical Engineering Ecole Polytechnique Montreal

ISBN: (纸本)9781424441211

Susceptibility-based negative contrast in magnetic resonance imaging (MRI) provides a mean to visualize magnetic microparticles. In the presence of a number of micropaticles in the field of view (FOV), the shape of the artifact is affected by the dipole-dipole interaction between the particles. Due to the limited spatial resolution of the clinical MR scanners, the exact positioning of the particles in MR images is not possible. However, the shape of the artifact can shed light on how the particles are distributed within the FOV. In this work, a simulation model and in-vitro experiments were used to study the shape and the amount of the susceptibility artifact for various spacing and angulations between the microparticles. The results showed that for a pair of identical particles with a diameter of D, the signal loss starts to change when particles are separated ～15×D and they become fully distinguishable when their distance reaches ～ 40×D.

关键词： precise registration Artifacts handicrafts Spatial resolution microparticles Scanner preclinical MRI scanner Intermolecular force Simulation models Magnetic Resonance Imaging C7orf49 gene

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Combining ISA extensions and subsetting for improved ASIP performance and cost

Combining ISA extensions and subsetting for improved ASIP pe...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Simon Rajotte Diana Carolina Gil J.M. Pierre Langlois Department of Computer Engineering and Software Engineering École Polytechnique de Montréal Montreal Canada

This paper presents a fine-grained configurable processor model used to generate image processing Application Specific Instruction Set Processors (ASIPs). A methodology to develop a minimal instruction set ASIP with the processor model is also proposed. The methodology is based on using specialized instructions in conjunction with Instruction Set Architecture (ISA) subsetting to reduce hardware costs and improve execution time. The performance of an FPGA implementation of the proposed processor model is measured for a two-dimensional Gaussian filter and results are compared to a popular commercial soft core processor. With ISA subsetting and specialized instructions, the proposed processor uses up to 45% fewer slices while achieving a 1.57× speedup.

关键词： Program processors Hardware XML Image processing Encoding Registers Convolution

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Analysis of deterministic end-to-end delay in multi-hop AFDX avionics network system

Analysis of deterministic end-to-end delay in multi-hop AFDX...

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作者： Ji, Xiaoqiang Li, Huanzhong Li, Jian Zhou, Hairui Hu, Fei Liu, Xue Zhu, Guchuan School of Software Shanghai Jiao Tong University Shanghai China School of Computer Science McGill University Montreal Canada Department of Computer Science and Engineering University of Nebraska Lincoln Lincoln United States Department of Electrical Engineering École Polytechnique Montréal Montreal Canada

ISBN: (纸本)9789898425485

Avionics Full Duplex Switched Ethernet (AFDX) is a deterministic communication protocol for real-time applications on Ethernet media. It is a promising technique that can improve the interconnection of electronic devices in an aircraft. One of the key challenges in employing AFDX is to determine the transmission delay in such a network. This paper aims at handling this challenge by theoretical analysis. A network calculusbased approach is presented for analyzing the end-to-end transmission delay of virtual links in an AFDX network that may consist of many network nodes with different scheduling disciplines. We further improve the approach by taking the specific effects of virtual links into account. In addition, we conduct a simulation to verify the validity of our approach. Simulation results show that switches with different scheduling disciplines can improve the delay performance in a multi-hop network.

关键词： Ethernet

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RAT: Robust animal tracking

RAT: Robust animal tracking

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International Workshop on Robot Sensing (ROSE)

作者： Rana Farah J.M. Pierre Langlois Guillaume-Alexandre Bilodeau Computer and Software Engineering Department École Polytechnique de Montréal Montreal QUE Canada

Determining the motion pattern of laboratory animals is very important in order to monitor their reaction to various stimuli. In this paper, we propose a robust method to track animals, and consequently determine their motion pattern. The method is designed to work under uncontrolled normal laboratory conditions. It consists of two steps. The first step tracks the animal coarsely, using the combination of four features, while the second step refines the boundaries of the tracked area, in order to fit more precisely the boundaries of the animal. The method achieves an average tracking error smaller than 5% for our test videos.

关键词： Animals Videos Target tracking Image edge detection Reflection Noise

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Evaluation of blocking probability in multiservice wireless networks

Evaluation of blocking probability in multiservice wireless ...

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IFIP Wireless Days, WD

作者： Ronald Beaubrun Wadia Ajinou Samuel Pierre Department of Computer Science and Software Engineering Université Laval Quebec Canada Department of Computer Engineering and Software Engineering École Polytechnique de Montréal Montreal Canada

This paper proposes a method that takes into account the diversity and requirements of multimedia traffic for evaluating blocking probabilities in multiservice wireless networks. For performance evaluation, we analyze the impact of traffic intensity on the blocking probability of each class of services, and compare the results obtained from simulation with those obtained numerically using the proposed method. We realize that, in general, the blocking probabilities obtained from the proposed method are close to those obtained from simulation.

关键词： Wireless networks Numerical models Mobile communication Analytical models Delay Markov processes Veins

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Encapsulation of Magnetotactic Bacteria for Targeted and Controlled Delivery of Anticancer Agents for Tumor Therapy

Encapsulation of Magnetotactic Bacteria for Targeted and Con...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society

作者： Fatemeh Afkhami Samira Taherkhani Mahmood Mohammadi Sylvain Martel NanoRobotics Laboratory Department of Computer and Software Engineering and Institute of Biomedical Engineering Ecole Polytechnique de Montreal (EPM)

ISBN: (纸本)9781424441211

We showed that magnetotactic bacteria (MTB) have great potentials to be used as microcarriers for targeted delivery of therapeutic agents. Indeed, magnetotaxis inherent in MTB can be exploited to direct them towards a tumor while being propelled by their own flagellated molecular motors. Nonetheless, although the thrust propelling force above 4 pN of the MC-1 MTB showed to be superior compared to other technologies for displacement in the microvasculature, MTB becomes much less efficient when travelling in larger blood vessels due to higher blood flow. In the latter case, a new technique developed by our group and referred to as Magnetic Resonance Navigation (MRN), has been successfully applied in larger vessels using synthetic microcarriers nut proved to be less efficient in the microvasculature due mainly to technological constraints. These findings called for the need to integrate both approaches by encapsulating MTB in special MRN-compatible microcarriers to be release in the vicinity of microvascular networks where they becomes more effective for targeting purposes in tumoral lesions. In this study Magnetococcus strain MC-1 were encapsulated in giant vesicles. The survival of the encapsulated bacteria was monitored. The release of bacteria from giant vesicles was also studied in different time intervals and conditions.

关键词： MAGNETOTACTIC BACTERIA Microvasculature Antineoplastic Agents thrust Blood Flow Blood Circulation encapsulation Time intervals Tumours

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