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More than 80% of gastric cancer is attributable to stomach infection with Helicobacter pylori (Hp), even though the bacterium is not always present at time of diagnosis. Infection is thought to lead to cancer by promoting the accumulation of oncogenic mutations downstream of inflammation; once oncogenic pathways become activated, infection may become dispensable for cancer development. Gastric preneoplastic progression involves sequential changes to the tissue, including loss of parietal cells, spasmolytic polypeptide-expressing metaplasia (SPEM), intestinal metaplasia (IM) and dysplasia. In mice, active KRAS expression recapitulates these tissue changes in the absence of Hp infection. This model provides an experimental system to investigate whether Hp infection has additional roles in preneoplastic progression, beyond initiating inflammation. Mice were assessed by evaluating tissue histology, gene expression changes, the immune cell repertoire, and expression of metaplasia and dysplasia markers. Compared to Hp-/KRAS+ mice, Hp+/KRAS+ mice had i) severe T cell infiltration and altered macrophage polarization; ii) altered expression of metaplasia markers, including increased expression of CD44v9 (SPEM) and decreased expression of TFF3 (IM); iii) more dysplastic (TROP2+) glands; and iv) greater proliferation of metaplastic and dysplastic glands. Hp was able to persistently colonize the stomach during the onset of these tissue changes, and eradication of Hp with antibiotics prevented metaplastic, dysplastic and proliferation marker changes. Collectively, these results suggest that gastric preneoplastic progression differs between Hp+ and Hp-cases, and that sustained Hp infection can promote the later stages of gastric preneoplastic progression, in addition to its established role in initiating chronic inflammation.

More than 80% of gastric cancer is attributable to stomach infection with Helicobacter pylori (Hp). Gastric preneoplastic progression involves sequential tissue changes, including loss of parietal cells, metaplasia and dysplasia. In transgenic mice, active KRAS expression recapitulates these tissue changes in the absence of Hp infection. This model provides an experimental system to investigate additional roles of Hp in preneoplastic progression, beyond its known role in initiating inflammation. Tissue histology, gene expression, the immune cell repertoire, and metaplasia and dysplasia marker expression were assessed in KRAS+ mice +/−Hp infection. Hp+/KRAS+ mice had severe T-cell infiltration and altered macrophage polarization; a different trajectory of metaplasia; more dysplastic glands; and greater proliferation of metaplastic and dysplastic glands. Eradication of Hp with antibiotics, even after onset of metaplasia, prevented or reversed these tissue phenotypes. These results suggest that gastric preneoplastic progression differs between Hp+ and Hp− cases, and that sustained Hp infection can promote the later stages of gastric preneoplastic progression.

Refrigeration of platelets (4°C) provides the possibility of improving transfusion practice over the current standard-of-care, room temperature (RT) storage. However, the increased level of platelet activation observed at 4°C in vitro is cause for concern of uncontrolled thrombosis in vivo. In this study, we assessed the safety of 4°C-stored platelets by evaluating their response to physiologic inhibitors prostacyclin (PGI2) and nitric oxide (NO). Apheresis platelets were collected from healthy donors (n = 4) and tested on Day 1 (fresh) or Day 5 (RT- and 4°C-stored) after treatment with PGI2 and NO or not for: thrombin generation; factor V (FV) activity; intracellular free calcium, cAMP and cGMP; ATP release; TRAP-induced activation; aggregation to ADP, collagen, and TRAP, and adhesion to collagen under arterial flow. Data were analyzed using two-way ANOVA and post-hoc Tukey test for multiple comparisons, with significance set at P

A real sample of textile wastewater was successfully decolorized through a simple, fast and efficient photocatalytic treatment using polypyrrole as catalyst. In the optimized operational conditions, the photocatalytic treatment resulted in 95.8% decrease in the units of color and 91.2% photodecomposition. Photocatalysis reduced the COD values from 1111.04 mg L −1 to 71.43 mg L −1 , evidencing 93.6% reduction in the organic matter to be discharged. TOC was also efficiently reduced from 156.75 to 51.74. The efficiency of the photocatalytic process was maintained during repeated use when cycles of photocatalysis were followed by redoping of polypyrrole with 0.1 mol L −1 HCl solution. The same photodecomposition efficiency was achieved using sunlight irradiation for 30 min, with values of photodecomposition up to 98%. Tests of toxicity using Artemia saline resulted in 96.7% survival, indicating that the products generated in the photodecomposition are non-toxic.

In July 2010, the United Nations General Assembly explicitly recognized the human right to water and sanitation, reaffirming that clean drinking water is essential for the realization of all the human rights. Therefore, controlling water quality should be a priority. In this context, it is interesting to make a simple, sustainable and low-cost system, in order take control over water quality parameters. This project main goal is to design and implement a water quality monitoring system on distribution networks to population or another interesting environment. It incorporates a quick alert system of flooding on low-altitude zones. It has mobile communication interface, over GSM, GPRS or 3G network, to send alarm and monitoring signals En julio de 2010, la Asamblea General de las Naciones Unidas reconoció el derecho humano al agua y al saneamiento, reafirmando que el acceso a agua potable limpia es esencial para la realización de todos los derechos humanos. Por lo tanto, controlar la calidad del agua debe ser una prioridad. En este marco, es interesante realizar un sistema sencillo, sostenible y de bajo costo, que facilite el control de los parámetros de calidad del agua. El objetivo general de este trabajo es diseñar e implementar un sistema de de monitoreo de la calidad del agua en redes de distribución a la población u otros escenarios donde sea necesaria analizar la potabilidad de la misma. Además, incorpora un sistema de alerta ante la posible inundación de los embalses en zonas bajas o de interés general. Dispone de una interfaz de comunicaciones móviles, soportado sobre la red GSM, GPRS y 3G, para el envío de señales de monitoreo y alarma.

Study objective Serious adverse outcomes associated with skin and soft tissue infections are uncommon, and current hospitalization rates appear excessive. It would be advantageous to be able to differentiate between patients who require high-level inpatient services and those who receive little benefit from hospitalization. We sought to identify characteristics associated with the need for high-level inpatient care among emergency department patients presenting with skin and soft tissue infections. Methods We conducted a nonconcurrent review of existing records to identify emergency department (ED) patients treated for skin and soft tissue infections. For each case, we recorded the presence or absence of select criteria and whether the patient needed high-level care, defined as ICU admission, operating room surgical intervention, or death as the primary outcome. We applied recursive partitioning to identify the principal criteria associated with high-level care. Results We identified 2,923 patients, including 84 experiencing high-level events. Recursive partitioning identified 6 variables associated with high-level outcomes: abnormal computed tomography, magnetic resonance imaging, or ultrasonographic imaging result; systemic inflammatory response syndrome; history of diabetes; previous infection at the same location; older than 65 years; and an infection involving the hand. One or more of these variables were present in all 84 patients requiring high-level care. Conclusion A limited number of simple clinical characteristics appear to be able to identify skin and soft tissue infection patients who require high-level inpatient services. Further research is needed to determine whether patients who do not exhibit these criteria can be safely discharged from the ED.

BACKGROUND: Whole blood (WB) has been used in combat since World War I as it is readily available and replaces every element of shed blood. Component therapy has become standard; however, recent military successes with WB resuscitation have revived the debate regarding wider WB use. Characterization of optimal WB storage is needed. We hypothesized that refrigeration preserves WB function and that a pathogen reduction technology (PRT) based on riboflavin and ultraviolet light has no deleterious effect over 21 days of storage. STUDY DESIGN AND METHODS: WB units were stored for 21 days either at 4 C or 22 C. Half of each temperature group underwent PRT, yielding four final treatment groups (n = 8 each): CON 4 (WB at 4 C); CON 22 (WB at 22 C); PRT 4 (PRT WB at 4 C); and PRT 22 (PRT WB at 22 C). Testing was at baseline, Days 1-7, 10, 14, and 21. Assays included coagulation factors; platelet activation, aggregation, and adhesion; and thromboelastography (TEG). RESULTS: Prothrombin time (PT) and partial thromboplastin time increased over time; refrigeration attenuated the effects on PT (p /= 0.009). Aggregation decreased over time (p /= 0.001); losses were attenuated by refrigeration (p /= 0.001). Refrigeration preserved TEG parameters (p /= 0.001) and PRT 4 samples remained within normal limits throughout the study. Refrigeration in combination with PRT inhibited fibrinolysis (p /= 0.001) and microparticle formation (p /= 0.031). Cold storage increased shear-induced platelet aggregation and ristocetin-induced platelet agglutination (p /= 0.032), as well as GPIb-expressing platelets (p /= 0.009). CONCLUSION: The in vitro hemostatic function of WB is largely unaffected by PRT treatment and better preserved by cold storage over 21 days. Refrigerated PRT WB may be suitable for trauma resuscitation. Clinical studies are warranted.

This paper demonstrates a process by which multi-core processor thermal dynamics are modeled using a combination of commercially available high fidelity numerical simulators and system identification techniques. The process produces reduced order models suitable for Dynamic Thermal Management (DTM) controller designs. An example microprocessor package is provided to illustrate the technique. A simple DTM controller is developed and applied to the modeled system.

In recent years, there has been an increased emphasis on undergraduate research. High tech companies need research to keep them competitive. This paper addresses the issue of getting engineering and computer science students interested in focused engineering and computer science areas so they are excited about these topics and want to learn more by doing research in that area. Our method is to encourage the student to research and write an interest paper as a first step to writing a proposal to seek and do organized research. In order to evaluate this approach, a survey was completed by 57 students in an Academic Success and Professional Development class who were assigned the writing of an interest paper in engineering or computer science. Results show that the assignment was successful for some students in leading them to an area of research in which they were interested and in other cases learning that they were not that interested in a particular area. Other students found a second interest. In this assignment, some students used an engineering data base for the first time.

In order to have more students in engineering and computer science, we need more students interested in these fields. Many community college (CC) students believe that engineering is boring and has little to do with their lives, but also admit that they know very little about engineering. Our research question is: How can we best get the attention of CC students in order for them to get engineering and computer science on their radar screen to consider as a career? In particular, we are asking if a different approach is needed for underrepresented minority students than majority students. A survey was given to 72 students (21 minority) students at one non-metropolitan CC and 159 (112 minority) students at another. In this paper, we will compare the beliefs about engineering and computer science by ethnicity within each college and across the two CCs. Results show that a higher percentage of non-minority students at the first school are interested in engineering and computer science as a career (63%) than minority students (52%) and at the second school, a higher percentage of minority students (45%) than non-minority students (35%) are interested in engineering or computer science, even if about 20% of each group admit that they really don't understand what engineering is all about. The minority students appear to be more interested in working with robotics and are more likely to believe that engineering and computer science have nothing to do with their life than do non-minority students.

Background The platelet storage lesion causes loss of function and viability over time. A new paradigm for platelet storage is desired to enable safer, more effective transfusions while reducing waste. We hypothesized that repletion of Mg, which is chelated by citrate anticoagulant, could reduce platelet storage lesion severity when given in conjunction with storage at a refrigerated temperature. Methods Apheresis platelet units were collected from healthy donors and stored at 22°C or 4°C. On Days 0, 2, 4, and 8, samples were collected for analyses of receptor-mediated aggregation, coagulation, adhesion to collagen under flow, and viability. In the first series, samples were given an acute dose of MgSO4 before testing; in the second series, storage bags were supplemented with 0-, 3-, or 6-mM MgSO4. Results Acutely delivered MgSO4 induced a more rapid coagulation time in apheresis platelets, further enhanced by storage at 4°C. Platelet adhesion to a collagen surface while exposed to arterial shear rates (920 s) was enhanced by MgSO4 supplementation-acute MgSO4 had a large effect on adhesion of fresh platelets, which diminished more rapidly in 22°C samples, while storage with MgSO4 showed significant benefits even out to Day 4 at both temperatures. Although 4°C storage improves the longevity of platelet aggregation responses to agonists, MgSO4 supplementation did not change those responses. Conclusion Acute MgSO4 reduces clot time likely through the transient increase of free Ca. Limited differences between platelet function in acute delivery of and storage with MgSO4 diminish the possibility that Mg-induced metabolic inhibition of platelets synergizes with 4°C storage. Regardless, magnesium supplementation to platelets is an exciting possibility in transfusion because the adhesion response of 22°C-stored platelets on Day 4 is significantly enhanced when stored with 6-mM MgSO4.

Arizona and the United States need more engineers. It is well known that very few college freshmen choose engineering as a major. In addition, studies show that roughly 40% of students planning to study engineering and science change majors or fail to get their degrees. Students aspiring to be an engineer must take several years of mathematics courses. Mathematics is not popular. In a recent Noel-Levitz study, 45% of today's freshmen agreed with the statement, "Math has always been a challenge for me." A discouraging fact is that many high school and community college students know very little about engineering and thus do not even have it on their radar as a possible career. This team of authors have been working with precollege and community college students for over 10 years trying to increase the number of engineers. They have made many visits to community colleges and to high schools to talk about engineering. At the same time they had done research on these students to better understand them and to help determine the best practices to interest more students in engineering. This paper gives the results of surveys that have been given to high school and to community college students to try to determine their largest areas of ignorance or misunderstanding regarding engineering and computer science. This information can then inform how best to use a limited amount of time with undecided students to break down these barriers.

In this paper we consider the design and control of an airbreathing hypersonic vehicle. Such vehicles are characterized by non-minimum phase characteristics, instability, actuator saturation constraints, and lightly damped flexible modes. While traditional vehicle design has followed an iterative sequential procedure (with the controller design following an aero-centric vehicle design phase), an integrated vehicle-control design process (based on bilinear matrix inequalities) is considered in this paper. We consider several example problems to illustrate the advantages of such an approach.

A Windows/C/C++ personal computer- based program is developed and used to evaluate the performance of missile guidance and control systems. The program simulates a high-performance missile in pursuit of an evading target. The simulation includes realistic missile and actuator dynamics, an autopilot, several missile guidance laws, a seeker/ navigation system model, various target models, and several integration methods. Missile-target intercepts are simulated and graphically displayed using the C/ C++ programming language. This represents a considerable improvement over previous research due to the object- oriented structure, speed, maintainability, and ease of debugging that C/C+ + offers. For modularity, the program is organized into three blocks: program-user interface, simulation, and graphics. Various simulations are presented to demonstrate the utility of the program in the evaluation of missile guidance and control systems.

Two robust controller designs are presented for a twin lift helicopter system (TLHS). The TLHS configuration consists of two UH-60A Sikorsky Blackhawk helicopters jointly lifting a heavy payload. The first design presented considers the case in which the tethers connecting each helicopter to the load are equal in length, and the second considers the case in which the tether lengths are unequal. Both designs are based on a seven degree of freedom model linearized about hover. The primary objective of each controller is to minimize the control action and pitching motion required to stabilize the helicopters as they perform elementary manuevers. Initial controllers developed by solving a mixed sensitivity H ∞ problem are analyzed for robustness to model uncertainty using the structured singular value μ and new controllers are developed which are more robust with respect to the uncertainty.

In this paper, three methods are presented to enhance the performance of an unstable missile system in the presence of multiple saturating actuators. Each method involves the design of a saturation detection system, which modifies a nominal autopilot via online optimization and maintains, to the extent possible, the multivariable properties of the nominal design. To prevent saturation due to exogenous signals, disturbances and noises, in particular, an error governor is proposed. This system processes the error signals within the feedback loop and the state of the compensator, so that appropriately co-ordinated control surface deflections may be generated. Traditionally, such a system has been applied only to stable plants. In this paper, it is shown how to design such a system for unstable plants. To prevent saturation due to reference (acceleration) commands from the guidance system, a reference governor is proposed. Such a system has traditionally required access to the entire state of the plant as wel...

In this paper we consider limits of achievable performance for a class of scramjet-powered hypersonic aircraft. A simple 3-DOF model is used to illustrate the main ideas. The vehicle is characterized by unstable and non-minimum phase dynamics. The limitations introduced by the right-half plane zero and actuator saturation on achievable trajectories has been examined. In addition, we examine several vehicle configurations and consider fundamental limitations for the plant and closed loop performance. An optimization methodology that explicitly incorporates performance specifications into the design of vehicle is explored. The advantages of such an approach is illustrated with examples.

This paper examines the issues involved in controlling an air-breathing hypersonic vehicle (characterized by their unstable, non-minimum phase dynamics) in the presence of significant modeling uncertainty and nonlinearities (control saturations). Modeling of the vehicle exhaust (plume) is complicated, often requiring computational fluid dynamic (CFD) simulations to capture all relevant effects. The focus of this paper is on obtaining a control law that maintains the vehicle trajectory within an acceptable tube while enforcing control constraints in the presence of modeling uncertainty. A robust domain of attraction based approach is used to generate/validate a feasible tube. The computational aspects of such an approach is examined, and the benefits of a decentralized control technique is considered. This approach is compared with other techniques such as linear matrix inequalities based controller design. These approaches are applied to a command following scenario in order to illustrate the performance of the proposed approach.

In this paper, two methods are presented to enhance the performance of unstable missile system in the presence of saturating actuators. Each method involves the design of a saturation detection system which modifies a nominal autopilot via on-line optimization and maintains, to the extent possible, the multivariable properties of the nominal design. Each method is applied to the problem of controlling an unstable bank-to-turn (BTT) missile.

In this paper, we consider the problem of financial portfolio optimization. A hierarchical framework is used, and receding horizon control (RHC) ideas are exploited to pose and solve two relevant constrained optimization problems. We first present the classic problem of wealth maximization subject to risk constraints. We also formulate a new approach to portfolio optimization which attempts to minimize the peak risk over the prediction horizon, while trying to track a wealth objective. This approach is designed to assist investors that might be unable to precisely specify their risk tolerance. We compare this methodology with the classical approach. It is concluded that this approach may be particularly beneficial during downturns — appreciably limiting losses during downturns while providing most of the upturn benefits.

This paper examines control-relevant modeling issues for a class of scramjet-powered hypersonic vehicles. A simple nonlinear 3DOF model is used to illustrate the main ideas. Two different plume modeling methodologies from previous literature are compared to a newly developed methodology. The impact of the modeling method on vehicle design has been examined. Nominal control design robustness issues are also addressed.

Within this paper, control-relevant vehicle design concepts are examined using a widely used 3 DOF (plus flexibility) nonlinear model for the longitudinal dynamics of a generic carrot-shaped scramjet powered hypersonic vehicle. The impact of elevator size and placement on control-relevant static properties (e.g. level-flight trimmable region, trim controls, Angle of Attack (AOA), thrust margin) and dynamic properties (e.g. instability and right half plane zero associated with flight path angle) are examined. Elevator usage has been examine for a class of typical hypersonic trajectories.

In this paper, an overview is provided of control efforts implemented using the scramjetpowered hypersonic vehicle model developed by Bolender, Doman, et.al. (2005-2009). The nonlinear model is characterized by unstable non-minimum phase dynamics with aeroelastic-propulsion coupling and nonlinear propulsion constraints. The viability of simple inner-outer loop single-input single-output (SISO) control structures is examined and quantified. Reference command and control amplitude and bandwidth tradeoffs are addressed. A simple (non-scheduled ) inner-outer loop control law is shown to yield excellent tracking of a constant (q = 2076 psf) dynamic pressure guidance command profile from Mach 5.7 to Mach 12. Robustness, gain scheduling as well as multivariable control issues are also addressed.

This paper makes use of the direct heuristic dynamic programming design in a nonlinear tracking control setting with filtered tracking error. A Lyapunov stability approach is used for the stability analysis of the tracking system. It is shown that the closed-loop tracking error and the approximating neural network weight estimates retain the property of uniformly ultimate boundedness under the presence of neural network approximation error and bounded unknown disturbances under certain conditions.

Scramjet powered hypersonic vehicles represent the next critical step toward achieving NASA's vision for Highly Reliable Reusable Launch Systems (HRRLS), affordable space access, planetary re-entry systems, and global reach vehicles. The design of such vehicles is a very interdisciplinary and highly complex problem. As such, the development of varying fidelity mathematical models for assessing overall stability and performance during the design process is very important. In particular, developing “low-order” models with “sufficient fidelity” to capture control-centric phenomena becomes vital in early stages of vehicle design. Historically, the early stage vehicle design process never incorporated control related considerations. The design obtained by such practice is not optimal and can often lead to poor design from a stability and performance view point. This paper presents control-relevant modeling efforts which will facilitate quick iterative control analysis and design during early stages of vehicle design. The paper is intended to be of an introductory nature and presents the high level modeling framework and associated challenges. An example linear 6 DOF model with some representative analysis is also given to demonstrate the applicability of the tool suite.

In this paper, we provide an overview of scramjet-powered hypersonic vehicle modeling and control challenges. Such vehicles are characterized by unstable non-minimum phase dynamics with significant coupling and low thrust or FER (normalized fuel equivalency ratio) margins. Recent trends in hypersonic vehicle research is summarized. To illustrate control system design issues and tradeoffs, a generic nonlinear 3DOF longitudinal dynamics model capturing aero-elastic-propulsive interactions for wedge-shaped vehicle is used. The model is analyzed over a broad range of hypersonic flight conditions (i.e. operating points). The paper highlights how vehicle level-flight static (trim) and dynamic properties change over the trimmable air-breathing corridor (∼ Mach 4.75-12.6, 70-115 kft). Particular attention is paid to thermal choking constraints imposed on control system design as a direct consequence of having a finite FER margin. The dependence of FER margin on altitude, Mach, and the bow flow turning angle is discussed. The latter depends on Mach, altitude, angle-of-attack (AOA), and forebody flexing. It is (briefly) discussed how FER margin can be estimated on the basis of Mach, altitude, and AOA if a flexing upper bound is assumed. The implication of this state-dependent nonlinear FER margin constraint as well as that of the right half plane (RHP) zero, associated with the elevator-flight path angle (FPA) map, on control system bandwidth (BW) and FPA tracking are discussed. It is argued that while the non-minimum phase zero limits the achievable closed loop FPA BW, FER coupling into FPA can be used to address this. This, however, is limited by FER margin limits and may impose constraints on the size of the FPA (and velocity) commands that can be followed. This is particularly important because the vehicle is inherently unstable which implies a closed loop system (with a finite downward gain margin) that can become destabilized if driven sufficiently deep into control saturation. A consequence of this is that designers must take note of the fact that FPA commands which are sufficiently large and/or rapid may be impossible to follow with the desired level of fidelity. This is quantified within the paper. Speed command following issues are also discussed.

*Morphing research projects will revolutionize the costs of building and operating aircraft. These technologies will enable aircraft to be more effi cient and operate under a wide range of varying flight conditions. Morphing technologies will be used to improve aircraft performance, expand its flight envelope, replace conventional control surfaces, reduce drag to improve range and reduce vibration/flu tter. There might never be a single solution for a morphing aircraft. The suitability of a type of morphing technology that is integrated into an aircraft will be dependent on size, range and flight performance envelope. The largest economical motivator for morphing aircraft will be the economies of scale of having a fleet of single type of morphing aircraft capable of fulfilling a variety of mission objectives and functions under many flight conditions , as opposed to a fleet of several types of aircraft , each tailored for specific missions , and their corresponding maintenance and support requirements. It is the objective of this survey paper to organize and summarize the many varying projects, concepts , and technologies of morphing aircraft. This surve y is not all inclusive. The two general approaches to morphing aircraft technologies are a Materials and Structural Approach , and a MultiDisciplinary Optimization and Systems Approach.

In many applications, it is essential to limit control signals. This paper presents methods that process accessible system signals (e.g., plant and compensator states, reference commands) to limit control signals. In contrast to "classical techniques" which limit variables by unnecessarily reducing control system bandwidth, the proposed methods limit variables in a nonconservative manner, reducing bandwidth only when necessary. A fundamental contribution of this work is that the methods presented are applicable to linear parameter varying (LPV) and quasi-LPV plants and controllers. The methods presented rely on appropriately "scaling back" key signals. The methods are conservative in that they are applicable to "slowly varying" LPV systems. Although the methods require access to all internal closed loop system state variables, one could use an appropriately designed LPV state estimator, if necessary. The Error Governer (EG) methods are applied to an LPV missile autopilot example.

This paper describes the synthesis of a dynamic compensator for a flexible space telescope described by a 280/sup th/ order finite-element NASTRAN-based model. The control objective is to attenuate the induced LOS jitter by a factor of 40 dB over the open loop value. A combination of low authority control (LAC) followed by high authority control (HAC/sub /spl infin//) which utilizes the H/sup /spl infin// optimal control methodology make up the hierarchical control system developed in this paper. The final design is shown to offer the required performance and robustness. The LAC loop is made up of two loops which provide broadband modal damping, modal spillover robustness, and actuator mode stabilization; all of which help in the design of the HAC/sub /spl infin//. The HAC/sub /spl infin// loop controller order is reduced from 130-states to 60-states by applying frequency-weighted balanced truncation techniques. The resulting hierarchical HAC/sub /spl infin///LAC controller is robustly stable against /spl plusmn/10% variation in actuator and sensor modeling.

In this paper, a method is presented for enhancing the performance of a stable EMRAAT bank-to-turn (BTT) missile in the presence of multiple saturating actuators. The method involves the design of a saturation detection system, called an error governor which maintains, to the extent possible, the multivariable properties of the original autopilot design. The system prevents saturation, ensures finite-gain L/sup /spl infin// stability, and maintains, to the extent possible, the directionality properties of the original autopilot.

Spacecraft which use control moment gyroscopes (CMGs) as momentum exchange devices in an attitude control system suffer from CMG configurations which preclude arbitrary torque generation. The exploitation of CMG null-space motion which exists in redundant systems allows the development of CMG steering laws which attempt to avoid these singular configurations. This paper presents a new singularity avoidance CMG steering law which operates by converging to a set of "preferred" trajectories in which no singular points exist. The underlying principle of CMG preferred trajectories as well as proof of the stability of the convergence process to these trajectories is presented. Simulation results demonstrating the convergence process as well as the resulting singularity avoidance properties are presented as well.

In this paper, a method is presented for enhancing the performance of an unstable missile system in the presence of multiple saturating actuators. The method involves the design of it saturation detection system which modifies a nominal autopilot via online optimization and maintains, to the extent possible, the multivariable properties of the nominal design. The method relies on missile state estimates.

Two H/sup infinity / controller designs are presented for a twin lift helicopter system (TLHS). The TLHS configuration consists of two US-60A Sikorsky Blackhawk helicopters jointly lifting a heavy payload. The first design presented considers the case in which the tethers connecting each helicopter to the load are equal in length, and the second considers the case in which the lengths are unequal. Both designs are based on a seven-degree-of-freedom model linearized about hover. The primary objective of each controller is to minimize the control action and pitching motion required to stabilize the helicopters as they perform elementary maneuvers. A simulation of a typical TLHS command scenario is used to evaluate the stability robustness characteristics of the resulting two feedback systems with respect to structured parametric uncertainty. >

This educational research endeavor describes the development of a Windows/C++ PC environment designed to visualize and evaluate the performance of a Twin Lift Helicopter System (TWS) under automatic control. The TLHS consists of two Sikorsky UH-60A Blackhawk helicopters, jointly lifting a heavy payload. The program-user interface permits users to change critical model and control law parameters in real-time. TLHS and control system dynamics are numerically computed and used to update graphics and animation on the screen. The utility of the program for evaluating TLHS performance and teaching fundamental systems and control concepts is discussed.

The design of a decoupling compensator for the Apache helicopter is presented. The design is based on linear quadratic regulation with implicit model following. A decoupling compensator is designed for a reduced-order linear model of vehicle dynamics at hover using eigenstructure assignment. The resulting closed-loop system is used as a reference model in the design of a compensator for the full-order system, resulting in a constant state feedback matrix. A feedforward matrix (command mixer) is then designed to diagonalize the system at low frequencies. The design is evaluated with both the full-order linear model and a nonlinear simulation, ARMCOP. It is found to provide desired bandwidth and good decoupling properties with the linear model. The nonlinear simulation shows increased coupling due to the nonlinearities.

In this paper, a method is presented for governing the release of wafers (starts) into a re-entrant semiconductor fabrication line. A flow model for a five-machine six-step re-entrant mini-fab is used to present all developments. Stabilizing clear-a-fraction (CAF) state feedback policies are developed for the mini-fab. A systematic procedure is presented for regulating the flow of starts so that critical system constraints (e.g. machine availability and buffer level constraints, etc.) are never violated, however aggressive the release policy. The regulation is achieved via nonlinear optimization based on state information from the flow model. The resulting algorithm, called a release policy governor (RPG), is shown to produce a closed loop stable system.

Introduction Severe trauma with tissue damage and shock can rapidly ( aPC inactivates factor Va (FVa) as part of normal hemostasis, but our previous results indicate that aPC at trauma levels is not sufficient to prevent coagulation, particularly when platelets are present, as platelet fVa is resistant to aPC [Campbell JE, PLoS ONE 9:e99181 (2014); Camire RM, Blood 91:2818 (1998)]. Tissue Factor Pathway Inhibitor (TFPI) is an endothelial-bound protein which inhibits coagulation through effects on factor Xa and the factor VIIa-tissue factor complex. It is released in the plasma (normal level 2.5nM, pathophysiologic states including trauma up to 10nM) and is typically cleared by the liver or kidneys. TFPIα accounts for 20% of circulating TFPI and binds FV and FVa [Ndonwi M, J Thromb Haemost 10:1944 (2012)]. Recently, a truncated FV (termed FV-short) produced by an autosomal dominant mutation was found to form complexes with TFPIα, resulting in retention of TFPIα in a 10-fold increase over normal levels in affected individuals [Vincent LM, J Clin Invest 123:3777 (2013)]. FV-short has significantly reduced thrombogenic potential and, by concomitantly raising TFPIα, causes a bleeding disorder. We hypothesize that the activation of PC in acute trauma may result in the production of FV-degradation products which could stabilize TFPIα similarly to the effect of FV-short. The combination of reduced FVa and increased TFPIα may contribute to ATC. Methods Whole blood from healthy volunteers was drawn by phlebotomy into ACD-containing tubes. Platelet-rich plasma (PRP) and platelet-poor plasma (PPP) were collected by centrifugation (200g for 10 min and 1000g for 15 min, respectively). Calibrated automated thrombogram (CAT) assays and thromboelastography (TEG) were conducted using PRP and PPP with exogenously delivered aPC (0, 100pM, or 1nM) and TFPI (0, 2.5nM, or 10nM). An immunodepleted FV-deficient ( Results CAT assays verified that aPC and TFPI each delay and suppress thrombin generation in PPP in a dose-dependent manner, but the combination of aPC and TFPI had a synergistic effect at the highest doses tested. The endogenous thrombin potential (ETP) was eliminated in PPP (control: 1663 nM-min; 1nM aPC + 10nM TFPI: 0 nM-min; P60 min; P60 min, P Conclusions In vitro studies suggest that PC activation is not the sole cause of ATC; the concentrations of aPC measured in trauma patient blood have little effect on the coagulation potential of plasma with or without platelets when aPC is delivered exogenously. The results here demonstrate that there is a synergistic effect between aPC and TFPI. When TFPI is added to FV deficient plasma, the thrombin generation is delayed and suppressed; however, in normal plasma digested with aPC (containing fragmented FVa), the addition of TFPI is sufficient to suppress the generation of thrombin beyond the window of measurement (>60 min). The addition of platelets to the milieu eliminated the effects of aPC, TFPI, and the combination on thrombin generation, highlighting the central role of platelets in maintaining hemostatic function. Disclosures No relevant conflicts of interest to declare.

The CBI architecture [1] being used as the basis of GENESIS 3 (G-3) allows a single model-container to be used to describe a model spanning many levels of scale. This feature allows a user to transparently run multi-scale simulations. As will be described in further detail during the workshop “Multi-Scale Modeling in Computational Neuroscience II: Challenges and Opportunities", the CBI architecture contains a communication component to upscale and downscale numerical variables when moving across different levels of scale. These new capabilities and advances in G-3 usability also allow interfacing with many Python graphical tools (e.g. wxPython, matplotlib), potential web interfaces (e.g. Django), and other independent modules (e.g. Chemesis-3) for use in simulations that cover multiple levels of scale. Progress in developing Python interfaces to G-3 [2], combined with recent implementation of network and biochemical modeling capabilities in G-3 have allowed us to construct a new series of self-guided hands-on modeling tutorials. These are being introduced at the Introduction to Genesis 3 Workshop held in Luebeck, Germany 30 April – 5 May 2012 (https://www.gradschool.uni-luebeck.de/index.php?id=366). This poster provides an introduction to these new modeling capabilities, and to the new instructional material. Additions to the existing G-3 tutorials on use of the G-shell cover network creation commands and the use of the Chemesis-3 module. The rewritten version of the tutorial "Creating large networks with GENESIS" demonstrates the use of Python scripting to create cortical network models in G-3. The tutorial "Adding a GUI to G-3 simulations" shows users how to leverage the Python programming interface to construct visual tools. As an example, Figure ​Figure11 illustrates the use of the new G-3 Netview visualization application to display and replay an animation of the spreading excitation in the RSnet2 simulation that is the basis of the GENESIS network modeling tutorial. Figure 1 A short injection pulse applied to a 32 x 32 cell network of coupled excitatory cells starts a wave of excitation that can be replayed and examined in detail during any time window, using the G-3 Network Viewer.

The motivation for the work is aircraft guidance in a time controlled air traffic management system (ATM). This paper discusses two forms of optimal dynamic interpolation guidance (ODIG) and the effects of turbulence on its performance. The first form of ODIG is based on a cost functional that penalizes acceleration. The second form of ODIG penalizes both acceleration and velocaty excursion. Both have been applied to the L1011-100 vertical guidance problem in the presence of turbulence (the Dryden turbulence model was used). A flight management system's (FMS) vertical flight plan is used to obtain waypoints which serve as inputs to the ODIG algorithm. The algorithm produces reference commands which are issued to a certified FAA L1011-100 model and an autopilot. The resulting dynamic behavior is compared to the results obtained from reference commands produced by an L1011-like commercial aircaft's flight management system model (FMSM) under the same turbulence.

In this paper, dynamic interpolation is applied to an L1011-100 vertical guidance problem. A flight management system's (FMS) optimized vertical flight plan is used to obtain way points which serve as inputs to the dynamic interpolation algorithm. The algorithm produces reference commands which are issued to a model obtained from a certified FAA L1011-100 and autopilot. The resulting dynamic behavior is compared to the results obtained from reference commands produced by an L1011-like commercial aircraft FMS. Quadratic and cubic spline solutions to the dynamic interpolation problem are presented. Performance degradation with respect to weight uncertainty is examined for both the FMS and the Dynamic Interpolation commands.

This paper presents guidelines for developing a multivariable centralized automatic flight control system (AFCS) for a twin lift helicopter system (TLHS). Singular value ideas are used to formulate performarce and stability robustness specifications. A Linear-Quadratic-Gaussian with Loop Transfer Recovery (LQG/LTR) design is obtained and evaluated.

Direct sampled-data design techniques which use "lifting" concepts that capture the periodic structure of the sampled data system in order to obtain a tractable optimization problem that accommodates meaningful (weighted H/sup /spl infin//) closed loop performance specifications as well as sample rate and intersample behavior is proposed. Direct sampled-data design controller has similar complexity as discretized classical designs but operates at a much lower sampling rate. FPGA implementation data is presented for each design. Comparisons demonstrating the benefits of the sampled-data approach in achieving reasonable trade-offs are presented.