M&S-based design of embedded controllers on network processors

With increasing computer capabilities, numerical modeling of two-phase flows has developed significantly over the last few years. Although there are two main categories, namely 'one' fluid and 'two' fluid methods, the 'one' fluid methods are more commonly used for tracking or capturing the interface between two fluids. Level set (LS), volume-of-fluid (VOF), front tracking, marker-and-cell (MAC) and lattice Boltzmann (LB) methods are all 'one' fluid methods. It is clear that there is no perfect method; each method has advantages and disadvantages which make it more appropriate for one kind of problem than for others. For instance, a LS method will accurately compute the curvature and the normal to the interface, but tends to loss mass which is physically incorrect. On the other hand, a VOF method will conserve mass up to machine precision, but the computation of the curvature and normal to the interface is not as accurate. In order to minimize the disadvantages of these methods, several authors have used two or more methods together to model two-phase flows. This is the case for the CLSVOF (Couple Level Set Volume Of Fluid) method, where LS and VOF are coupled together in order to better capture the interface. In CLSVOF, the level set function is used to compute the interface curvature and normal to the interface, while the volume of fluid function is used to capture the interface. For two-phase flows in microchannels, surface tension forces play an important role in determining the dynamics of bubbles whereas gravitational forces are generally negligible. Also it is very important to consider the interaction between the boundaries and the fluids by prescribing or computing the correct contact angle between them. The commercial CFD code FLUENT allows the use of static constant angles, or the use of User Defined Functions (UDF) to compute the dynamic contact angles. It is inappropriate to use a static contact angle to model cases involving moving contact lines. For such cases a dynamic contact angle scheme should be implemented. In this study, FLUENT was used to model adiabatic and diabatic, time dependent two-phase flows. Since FLUENT already contains a VOF method, a LS method was implemented and coupled with VOF into FLUENT via UDFs. Furthermore, since the LS function, used to compute the surface tension force, ceases to be a signed distance to the interface even after one time step, a re-initialization equation was solved after each time step. This involved using a fifth order WENO (Weighted Essentially Non Oscillatory) scheme to discretize the space derivatives (otherwise oscillations of the interface occurred), and a first order Euler method for the time integration. In another part of the study, a 3D dynamic contact angle model based on volume fraction, interface reconstruction, and experimentally available advancing and receding static contact angles was also developed and implemented into FLUENT via UDFs. Several validations for the developed CLSVOF method and dynamic contact angle model are presented in this thesis, these includes a static bubble, a bubble rising in a stagnant liquid for Morton numbers ranging from 102 to 10-11, droplet deformation due to a vortex flow field, droplets spreading over a wall under the gravity effect and droplets sliding over a wall due to gravity. These validations demonstrated the high accuracy and the stability of our methods for modeling these phenomena. A heat and mass transfer model was also implemented into the commercial CFD code FLUENT for simulating of boiling (and condensation) heat transfer. Several simulations were presented with water and R134a as working fluids. The influence of the contact angle and the wall superheat was also studied.

Interfacial delamination in polymer coated metal sheet : a numerical-experimental study

Effects of self energy of the ions on the double layer structure and properties at the dielectric interface

We discuss the design and development of an infrastructure for serious gaming applications using a formal Modeling and Simulation environment based on the DEVS formalism. The research uses the RISE simulation middleware services to build a serious game application that can be deployed on a mobile device using a properly developed mobile client. We propose a mobile client that leverages the cloud services provide by a RISE server to obtain simulation data to be used in a serious gaming application. In particular, our prototype provides a stock trading game. The simulation model is based on a Brownian motion economic model that has been analyzed comparatively to real data.

Quickly accessing the contents of a video is challenging for users, particularly for unstructured video, which contains no intentional shot boundaries, no chapters, and no apparent edited format. We approach this problem in the domain of lecture videos though the use of machine learning, to gather semantic information about the videos; and through user interface design, to enable users to fully utilize this new information. First, we use machine learning techniques to gather the semantic information. We develop a system for rapid automatic semantic tagging using a heuristic-based feature selection algorithm called Sort-Merge, by using large initial heterogeneous low-level feature sets (cardinality greater than 1K). We explore applying Sort-Merge to heterogeneous feature sets though two methods: early fusion and late fusion. Each takes different approaches to handling the different kinds of features in the heterogeneous set. We determine the most predictive feature sets for key-frame filters such as “has text”, “has computer source code”, or “has instructor motion”. Specifically we explore the usefulness of Harr Wavelets, Fast Fourier Transforms, Color Coherence Vectors, Line Detectors, Ink Features and Pan/Tilt/Zoom detectors. For evaluation, we introduce a “keeper” heuristic for feature sets, which provides a method of performance comparison against a baseline. Second, we create a user interface to allow the user to make use of the semantic tags we gathered though our computer vision and machine learning process. The interface is integrated into an existing video browser, which detected shot-like boundaries and presented a multitimeline view. The content within shot-like boundaries is represented by frames to which our new interface applies the generated semantic tags. Specifically, we make accessible the semantic concepts of 'text', 'code', 'presenter', and 'person motion.' The tags are detected in the simulated shots using the filters generated with our machine learning approach and are displayed to users using a user-customizable multi-timeline view. We also generate tags based on ASRgenerated transcripts that have been limited to the words provided in the index of the course text book. Each of these occurrences is aligned with the simulated shots. Each spoken word becomes a tag analogous to the visual concepts. A full Boolean algebra over the tags is provided to enable new composite tags such as 'text or code, but no presenter.' Finally, we quantify the effectiveness of our features and our browser through user studies, both observational and task driven. We find that users that use the full suite of tools performed a search task in 60% of the time of users without access to tags. We find that when users are asked to perform search tasks they follow a nearly fixed pattern of accesses, alternating between the use of tags and Keyframes, or between the use of Word Bubbles and the media player. Based on user behavior and feedback, we redesigned the interface to group spatially interface components that are used together, removed un-used components, and redesigned the display of Word Bubbles to match that of the Visual Tags. We found that users strongly preferred the Keyframe tool, as well as both kinds of tags. Users also either found the algebra very useful or not useful at all.

Chemical processes at the interfaces often differ kinetically and mechanistically from the bulk counterparts, partly due to the concentration inhomogeneity of different chemicals at the interfaces. The fractionation of chemicals at the interfaces not only determines their interfacial concentrations, but also affects the physicochemical properties of the interfaces. In this thesis, three sets of chemicals/interfaces with important environmental implications are studied: (1) anion fractionation at the gas–liquid microdroplet interfaces, (2) fractionation of perfluoroalkyl surfactants and matrix components at the bubble–water interface in ultrasonically irradiated solutions, and (3) ion fractionation across the ice–water interface during the freeze–thaw cycle of electrolyte solutions. The relative anion affinity for the air–water interface, as measured by Electrospray Mass Spectrometry (ES–MS), is exponentially correlated with ionic radius. The affinities respond differently to different additives, suggesting that specific anion effects are due to different energy levels of physical interactions. Relative anion affinities at the air–methanol interfaces are almost identical to those at the air–water interface, suggesting that surface structure is not the primary driving force for interfacial anion fractionation. Perfluoroalkyl carboxylates and sulfonates can be transferred from the ocean to marine aerosols due to their high affinity for the air–water interface, but transfer to gas phase is unlikely as they remain deprotonated in aqueous phase because of their low pKa. Organic matrix components may reduce the sonochemical kinetics of Perfluorooctanesulfonate (PFOS) and Perfluorooctanoate (PFOA) by competitive adsorption onto the bubble–water interface or by lowering the interfacial temperatures. Inorganic anions, but not cations, may significantly enhance or reduce the sonochemical kinetics of PFOS and PFOA. The specific anion effects following the Hofmeister series are likely related to anions’ partitioning to and interaction with the bubble–water interface. Time–resolved confocal fluorescence microscopy of freezing electrolyte solutions reveals that the thickness of interstitial liquid films depends non–monotonically on electrolyte concentration. It also confirms that selective incorporation of cations (anions) into the ice lattice decreases (increases) the pH of the interstitial liquid films. Since the magnitude of pH change during freezing is smaller than during the subsequent thawing process, it is likely to be limited by the seepage of proton or hydroxide slowly produced via water dissociation.

Chapter 2 - Benchmarking Network Processors

An overview of electrified interfaces structure and electronic properties of metal surfaces physics of surfaces ab-inito molecular dynamics - selected applications to disordered systems and surfaces the problem of Schottky barrier the semiconductor/electrolyte interface stark effect on adsorbates at electrified interfaces thermodynamics of adsorption electrode potentials and energy scales phenomenological approach to metal/electrolyte interfaces the application of scanning tunnelling microscopy to electrochemistry singly crystal electrodes modelling of metal-water electrified interfaces molecular models of organic adsorption from water at charged interfaces the interface between a metal and a solution in the absence of specific adsorption adsorption at the metal/solution interface electron-transfer reactions at metal-solution interfaces - an introduction to some contemporary issues the solid-electrolyte interface as exemplified by hydrous oxides - surface chemistry and surface reactivity discrete charges on biological membranes structural rearrangements in lipid bilayer membranes evaluation of the surface potential at the membrane-solution interface of photosynthetic bacterial systems electrical currents of the light driven pump bacteriorhodopsin the role of asp 85 and asp 96 on proton translocation the electrochemical relaxation at thylakoid membranes evaluation of the electric field in a protein by dynamic measurements of proton transfer.

Examples, Ion Properties and Concepts: The Past and What Can Be Learnt from It (W Kunz et al.) Specific Ion Properties (G Hefter) Ion-Surfactant Interactions: Experiments and Models (E Leonitis) Promising Experimental Techniques: Probing Specific Ion Effects with Grazing Incidence X-Ray Diffraction (J Daillant) Neutron Scattering, Simulation, Denaturants (P E Mason & G Neilson) Specific Ion Effects at The Air-Water Interface - New Experimental Studies (V Craig) Newest Results From Theory and Simulation: Simulations of Ions at the Air-Water Interface and Near Biomolecules (M Lund & P Jungwirth) Simulations of Ion Near Water-Solid Interfaces and in Bulk Water (R Netz & D Horinek) HNC Calculations of Specific Ion Effects (L Belloni) and other papers.

SummaryMulticore network processors have been playing an increasingly important role in computational processes, which emphasize on scalability and parallelism of the systems, in distributed environments especially in Internet‐based delay‐sensitive applications. It is an important but unsolved issue, however, to efficiently schedule tasks in network processors with multicore and multithread for improving the system throughput as much as possible. Profiling can gather runtime environment information and guide the compiler to optimize programs through scheduling tasks based on the runtime context. This paper proposes a profiling‐based task scheduling approach, targeting on improving the throughput of multicore network processor (Intel IXP) systems in the balanced pipeline way. In this work, we investigate a profiling‐based task scheduling framework, a task scheduling algorithm, and a set of performance models. Our task allocation scheme maps tasks onto the pipeline architecture and multiple threads of network processors in parallel, which incorporates the profiling context and global thread refinement. We evaluate our task scheduling algorithm by implementing representative network applications on the Intel IXP network processor. Experimental results demonstrate that our algorithm is able to schedule tasks in a balanced pipeline fashion and achieve the high throughput and data transmission rate. Copyright © 2012 John Wiley & Sons, Ltd.

Vitreo-retinal surgery encompasses the surgical procedures performed on the vitreous humor and the retina. A procedure typically consists of the removal of the vitreous humor, the peeling of a membrane and/or the repair of a retinal detachment. Operations are performed with needle shaped instruments which enter the eye through surgeon made scleral openings. An instrument is moved by hand in four degrees of freedom (three rotations and one translation) through this opening. Two rotations (? and ? ) are for a lateral instrument tip movement. The other two DoFs (z and ?) are the translation and rotation along the instrument axis. Actuation of for example a forceps can be considered as a fifth DoF. Characteristically, the manipulation of delicate, micrometer range thick intraocular tissue is required. Today, eye surgery is performed with a maximum of two instruments simultaneously. The surgeon relies on visual feedback only, since instrument forces are below the human detection limit. A microscope provides the visual feedback. It forces the surgeon to work in a static and non ergonomic body posture. Although the surgeon’s proficiency improves throughout his career, hand tremor may become a problem around his mid-fifties. Robotically assisted surgery with a master-slave system enhances dexterity. The slave with instrument manipulators is placed over the eye. The surgeon controls the instrument manipulators via haptic interfaces at the master. The master and slave are connected by electronic hardware and control software. Implementation of tremor filtering in the control software and downscaling of the hand motion allow prolongation of the surgeon’s career. Furthermore, it becomes possible to do tasks like intraocular cannulation which can not be done by manually performed surgery. This thesis focusses on the master console. Eye surgery procedures are observed in the operating room of different hospitals to gain insight in the requirements for the master. The master console as designed has an adjustable frame, a 3D display and two haptic interfaces with a coarse adjustment arm each. The console is mounted at the head of the operating table and is combined with the slave. It is compact, easy to place and allows the surgeon to have a direct view on and a physical contact with the patient. Furthermore, it fits in today’s manual surgery arrangement. Each haptic interface has the same five degrees of freedom as the instrument inside the eye. Through these interfaces, the surgeon can feel the augmented instrument forces. Downscaling of the hand motion results in a more accurate instrument movement compared to manually performed surgery. Together with the visual feedback, it is like the surgeon grasps the instrument near the tip inside the eye. The similarity between hand motion and motion of the instrument tip as seen on the display results in an intuitive manipulation. Pre-adjustment of the interface is done via the coarse adjustment arm. Mode switching enables to control three or more instruments manipulators with only two interfaces. Two one degree of freedom master-slave systems with force feedback are built to derive the requirements for the haptic interface. Hardware in the loop testing provides valuable insights and shows the possibility of force feedback without the use of force sensors. Two five DoF haptic interfaces are realized for bimanual operation. Each DoF has a position encoder and a force feedback motor. A correct representation of the upscaled instrument forces is only possible if the disturbance forces are low. Actuators are therefore mounted to the fixed world or in the neighborhood of the pivoting point for a low contribution to the inertia. The use of direct drive for ' and and low geared, backdriveable transmissions for the other three DoFs gives a minimum of friction. Disturbance forces are further minimized by a proper cable layout and actuator-amplifier combinations without torque ripple. The similarity in DoFs between vitreo-retinal eye surgery and minimally invasive surgery (MIS) enables the system to be used for MIS as well. Experiments in combination with a slave robot for laparoscopic and thoracoscopic surgery show that an instrument can be manipulated in a comfortable and intuitive way. User experience of surgeons and others is utilized to improve the haptic interface further. A parallel instead of a serial actuation concept for the ' and DoFs reduces the inertia, eliminates the flexible cable connection between frame and motor and allows that the heat of the motor is transferred directly to the frame. A newly designed z-?? module combines the actuation and suspension of the hand held part of the interface and has a three times larger z range than in the first design of the haptic interface.

High-order adaptive mesh refinement offers the potential for accurate and efficient resolution of problems in fluid dynamics and other fields where a wide range of length scales is present. A critical requirement for the interface closures used with these methods is stability in the context of hyperbolic systems of partial differential equations. In this study, a class of energy-stable high-order finite-difference interface closures is presented for grids with step resolution changes in one dimension. Asymptotic stability in time for these schemes is achieved by imposing a summation-by-parts condition on the interface closure, which is thus also nondissipative. Interface closures compatible with interior fourth- and sixth-order explicit, and fourth-order implicit centered schemes are presented. Validation tests include linear and nonlinear problems in one and in two dimensions with tensor-product grid refinement. A second class of stable high-order interface closures is presented for two-dimensional cell-centered grids with patch-refinement and step-changes in resolution. For these grids, coarse and fine nodes are not aligned at the mesh interfaces, resulting in hanging nodes. Stability is achieved by again imposing a summation-by-parts condition, resulting in nondissipative closures, at the cost of accuracy at corner interfaces. Interface stencils for an explicit fourth-order finite-difference scheme are presented for each geometry. Validation tests confirm the stability and accuracy of these closures for linear and nonlinear problems. The Richtmyer-Meshkov instability is investigated using a novel first-order perturbation of the two-dimensional Navier-Stokes equations about a shock-resolved base flow. The computational domain is efficiently resolved using the one-dimensional fourth-order interface scheme. Results are compared to analytic models of the instability, showing agreement with predicted asymptotic growth rates in the inviscid range, while significant discrepancies are noted in the transient growth phase. Viscous effects are found to be poorly predicted by existing models.

Raja Ramanna Centre for Advanced Technology (RRCAT) has two synchrotron radiation sources, Indus-1 and Indus-2. Microtron is the common injector to both the machines. A new, FPGA based, control system architecture is planned in which it supervises and monitors different subsystems present for the operation of Microtron with the help of Equipment Control Modules (ECMs). At present some subsystems communicate with operator console directly over RS232 interface such as the 'Tesla Meter' and the 'Temperature Scanner'. For modularity, those subsystems must be brought over RS485 interface and with unified pre-defined custom protocol for communication. In this paper monitoring of the Tesla Meter is proposed. An ECM communicates with Tesla Meter over RS32 interface and with an operator console over RS485 interface. Digital logic is designed in Verilog HDL and implemented in FPGA for RS232 and RS485 communication controllers, respectively. A protocol conversion unit between Tesla Meter and ECM is also implemented. For more feature, there is a need to capture data and store it for offline data analysis. Therefore, a circular buffer is also designed and simulated to review the history data from the ECM. The work has been completed using ModelSim XE and Xilinx ISE 8.2i softwares.

Programming network processors remains an art due to the variety of different network processor architectures and due to little support to reason and explore implementations on such architectures. We present a case study of mapping an IPv4 forwarding switch application on the Intel IXP1200 network processor and we compare this implementation with an analytical model of both the application and architecture used to evaluate different design alternatives. Our results not only show that we are able to model the IXP1200 and our application within 15% of the accuracy compared to that of IXP1200 simulation, but also find closely matching trends for different workloads. This shows the clear potential of such analytical techniques for design space exploration.

Pressure injuries are serious complications that are difficult and expensive to treat. Preventative strategies, such as alternating pressure mattress has been prescribed to patients with pressure injury in the hospital setting to prevent recurrence. However, the underlying mechanism of alternating pressure (AP) on tissue tolerance to ischemia is not explored to a full extent. The main purpose of this study was to investigate the protective mechanism of alternating pressure overlay on load-bearing tissue like sacrum in people with spinal cord injury (SCI). We hypothesized that the low-profile AP overlay would redistribute the interface pressure and subsequently increase the skin blood flow (SBF) to the sacral area when lying on top of an operating room (OR) pad. A secondary aim was to investigate if AP overlay could be used as a preconditioning strategy for weight-bearing skin at the sacrum. We hypothesize that after preconditioning with AP overlay, the interface pressure would remain unchanged during supine lying on OR, but SBF would increase. A repeated measures design was utilized on 15 adults with SCI. All the individuals underwent three protocols: supine lying on (1) OR pad only for 40 minutes (control), (2) OR pad with AP overlay for 40 minutes, and (3) OR pad only (AP-OR) for 40 minutes after AP (protocol 2). Outcome measures included interface pressure and SBF at sacrum. For the primary aim, we found that the peak interface pressure during AP-deflation (51.47±30.18 AU) was significantly lower than that during AP-inflation (89.27±53.92 AU) and OR (control protocol) (114.13±60.97 AU). The averaged SBF during AP-deflation (15.54±15.33 AU) was significantly higher than that during inflation (12.65±12.45 AU) and OR (control) (11.96±10.26 AU). For secondary aim, we found that peak interface pressure during AP-OR (104.62±58.17 AU) was significantly lower than that during OR (control) protocol (114.13±60.97 AU), and SBF during AP-OR (15.78±15.82 AU) was significantly higher than that during OR (control) (11.96±10.26 AU). Findings of this study suggested that alternating pressure overlay is an effective strategy to redistribute interface pressure and subsequently improves tissue perfusion at the weight-bearing area in people prone to pressure injury. Further study is warranted in other population at risk of pressure injuries