Automated Coordinated Mission Planning Across Constellations

In-Flight Precision Airdrop Planner Follow-On Development Program

Design of a High-Q, Low-Impedance, GHz-Range Piezoelectric MEMS Resonator

Inertial MEMS System Applications

Inertial Navigation Sensors

Momentum Dumping Using Only CMGs

Launch Vehicle Wind Look Ahead Guidance for Ascent Load Management

Microfabricated Biodegradable Scaffolds for Tissue Engineering of Vital Organs

The Inertial Stellar Compass (ISC): a Multifunction, Low Power, Attitude Determination Technology Breakthrough

Foot-to-Foot Range Measurement as an Aid to Personal Navigation

MARS Airplane Guidance and Navigation

SPORE Biomarker Detection Using a MEMS Differential Mobility Spectrometer

Average Connectivity Properties of Wireless Ad Hoc Networks

Robust Gaussian and Non-Gaussian Matched Subspace Detection

Subspace Learning and Innovation Characterization in Generalized Gaussian Noise

Micron-Gap ThermoPhotoVoltaics (MTPV)

MEMS Development at Draper Laboratory

Deeply Integrated Code Tracking: Comparative Performance Analysis

Nearly-Isentropic Energy Conversion with Quantum Excitation Transfer

Hall, R.A. et al.

Three-Pulse Minimal Fuel Rotations of Axisymmetric Spacecraft Using Reaction Control Thrusters

Achieving 10(-9) Dependability with Drive-by-Wire Systems

Fault-Tolerant Avionics Systems

Flight-Critical Distributed Systems - Design Considerations

Preventing Data Pollution in the Space Shuttle Cockpit

A Collaborative Modeling & Simulation Infrastructure

A Quantitative Approach for Determining the Level and Sophistication of Automation in Unmanned Vehicles

Spectrum Analysis Techniques for Personnel Detection Using Seismic Sensors

A Web-Enabled Space Station Simulation Development & Analysis Tool (eSim)

Design of Robust Nash Game Theoretic Controllers with Time Domain Constraints

Draper Station Analysis Tool (DSAT)

Multivariable Flex Model Reduction

Robust Momentum Manager Design for the Space Station with Momentum Capacity Constraint

Vascularized Tissue Enginering of Vital Organs: Design, Computational Modeling and Functional Testing

Ruggedized PC/104-Plus PowerPC Processor Card for Avionics

Design of a Single Capillary-Parenchymal Co-Culture Bioreactor Using a Self-Assembling Peptide Membrane

Development of Alternate Sources of Hemispherical Wheels for the 16 PIGA MOD-G (Interim Findings)

Electric Field Screening by Injected Charge in Polymer Light-Emitting Diodes

Electric Field Screening in Polymer Light-Emitting Diodes

A High-Mobility Tactical Micro-Robot System

Malcos, E.M.

Gold Bump Attachment of MEM Sensor Die Using Thermocompression Bonding

Vacuum Packaging of MEMS Inertial Sensors

A Surveillance Aerial Vehicle to Accompany Submarine-Launched Munitions

Surface-Mount Microfluidic Flow Regulator on a Polymer Substrate

Design of a Model Predictive Control Flight Control System for a Reusable Launch Vehicle

UUV On-Board Path Planning in a Dynamic Environment for the Manta Test Vehicle

A Satellite Data Link for HUMS Applications

Novotny, J. et. al.

Material Issues of Low Temperature Co-Fired Ceramic (LTCC) Fine Pitch Chip-Scale Package (CSP) Designs

Rapid Prototype Fabrication of Custom Chip-Scale Packages

A State Estimator Supporting Command and Control of Multiple Types of Aircraft Missions

State Estimation of Objects that Have and Have Not Been Observed

Autonomy: How Much Is Right for Future Commercial Applications?

INS/GPS Integration

Preparation and Use of Chip Capacitors in Ultra-Dense Multichip Modules

A Fast Approach to Multistage Launch Vehicle Trajectory Optimization

INS/GPS Integration Architectures

INS/GPS Integration Architecture Performance Comparisons

Architecture for Exploiting the Use of Video in Shipboard Sensing

An Approach to Custom CSP Package Fabrication

High-Q Silica Microsphere Optical Resonator Sensors Using Stripline-Pedestal Antiresonant Reflecting Optical Waveguide Couplers

Balance Prostheses for Postural Control

Fluid Damping in Resonant Flexural Plate Wave Device

MEMS Inertial Sensor Assembly for Vestibular Prosthesis

Sensor Assembly for Postural Control Balance Prosthesis

Camouflage of Network Traffic to Resist Attack (CONTRA)

Flex-Controller Interaction During Space Station Reboost

Single Satellite Orbital Figure-of-Merit

Autonomous Mission Manager for Rendezvous, Inspection, and Mating

10th Saint Petersburg International Conference on Integrated Navigation Systems

Saint Petersburg International Conference on Integrated Navigation Systems. 10th. Held in Russia, St. Petersburg, 05/26/2003 to 05/28/2003. (Draper Report no. CSDL-2004-039)

Subjects: NAVIGATION SYSTEMS, INERTIAL SYSTEMS, INERTIAL SENSORS, INTEGRATED SYSTEMS, SATELLITES

Abramson, M.; Collins, B.; Kolitz, S.; Ricard, M.; Scheidler, P.; Strauss, C.

Automated Coordinated Mission Planning Across Constellations

Earth Science Technology Conference (ESTC). Held in Adelphi, MD, 06/23/2003 to 06/26/2003. Sponsored by: NASA. (Draper Report no. P-4139)

Abstract: Draper has been developing a simulation testbed, the Earth Phenomena Observing System (EPOS), which includes an automated mission manager. The automated mission manager will reduce requirements on the human operators of satellites, improve system resource utilization, and provide the capability to dynamically respond to temporal terrestrial phenomena. Examples of triggering events are localized transient phenomena that have a significant impact on human life such as volcanic eruptions, weather (hurricanes, tornadoes, etc.), biomass burning (e.g., forest fires). The current effort is focusing on the Morning and Afternoon ("A Train") Constellations. The goal of these Constellations is to provide correlative measurements that will yield unprecedented cloud, climate, aerosol, and chemistry science. We are using MODIS Cloud Mask data from the MODIS instrument on Terra (in the Morning Constellation) as input into EPOS's mission manager. The EPOS mission manager uses these data to plan the pointing of the TES instrument on Aura (to be launched in 2004 as part of the A Train). In particular, TES pointing plans include high-value locations of interest that are not covered with clouds. We analyzed the timeliness of the Terra and Aqua MODIS data for use in this operational concept and found that for the 1400+ volcanoes found at the Smithsonian Institution Global Volcanism Program, the great majority of the data are timely for tasking TES and results in improved science data gathering. We present an overview of current enhancements being made to EPOS that will provide additional capabilities in optimized tasking of sensors for science data collection.

Subjects: EARTH PHENOMENA OBSERVING SYSTEM (EPOS), CONSTELLATIONS

Angermueller, K.; Hattis, P.; Fill, T.; Wright, R.; Benney, R.; LeMoine, D.; King, D.

In-Flight Precision Airdrop Planner Follow-on Development Program

Aerodynamic Decelerator Systems Conference. Held in Monterey, CA, 05/19/2003 to 05/22/2003. Sponsored by: AIAA. (Draper Report no. P-4093)

Abstract: An airdrop planning system that facilitates precision airdrop of ballistic and guided airdrop systems is undergoing follow-on development, having already achieved successful proof-of-concept prototype demonstration. The planning and wind/ density/ pressure modeling software in the Precision Airdrop System (PADS) have now been integrated onto a single laptop computer. User interfaces have been improved. New models of multiple- payload releases, humanitarian ration drops, and airdrops suffering parachute canopy failures upon exit have been added to the planning system models that were in the prototype. A graphical map interface has been added to indicate the expected payload release and impact points, with overlay displays of expected delivery accuracy footprints derived from a new Monte-Carlo-based delivery error analysis tool. New capabilities have also been added for handling and assimilating into the models used by the planning system the wind, density, and pressure data acquired while in transit to the drop zone. Initial testing of the follow-on airdrop planning system design has been successful. Delivery of ten systems and user documentation will occur under the current program to enable operator training and initial use in field operations.

Subjects: PRECISION AIR DROP

Antkowiak, B.; Gorman, J.P.; Varghese, M.; Carter, D.J.D.; Duwel, A.E.

Design of a High-Q, Low-Impedance, GHz-Range Piezoelectric MEMS Resonator

Solid-State Sensors, Actuators, and Microsystems (Transducers). 12th. Held in Boston, MA, 06/08/2003 to 06/12/2003. Sponsored by: IEEE/EDS. (Draper Report no. P-4078)

Abstract: In this paper, we present useful modeling procedures intended to characterize and optimize MEMS resonator-filter designs. We address two major areas: (1) the impedance of the resonators as a function of frequency, assuming a given damping value, and (2) the numerical calculation of resonator Quality factor (Q) due to known damping mechanisms. The impedance calculation procedure is targeted toward piezoelectric MEMS resonators, while the Q calculations are more general. We show how these modeling approaches have been used to design and optimize our piezoelectric resonator for high Q and low impedance in the GHz frequency range.

Subjects: MICROELECTROMECHANICAL SYSTEM (MEMS), RESONATORS, PIEZOELECTRICITY, Q FACTORS (HIGH Q)

Barbour, N.; Anderson, R.; Connelly, J.; Hanson, D.; Kourepenis, A.; Sitomer, J.; Ward, P.

Inertial MEMS System Applications

Advances in Navigation Sensors & Integration Technology. Held in London, UK, 10/20/2003 to 10/28/2003. Sponsored by: NATO. (Draper Report no. P-4153-REV-A)

Abstract: The performance of Microelectromechanical Systems (MEMS) inertial technology has evolved from automotive quality to that approaching tactical-grade quality (1 deg/h, 1 mg). This evolution is a direct result of advances made in the key technology areas driven by gun-launched projectile requirements. The application of silicon MEMS inertial technology to competent munitions efforts began in the early 1990s. Initially, gun hardness was demonstrated at the sensor level, although the bias-and-scale factor of these gyros and accelerometers was mostly suitable for automotive or commercial use. Subsequently, development programs were initiated to develop gun-hard inertial systems with greatly improved sensor performance, and with a goal of low production cost. This paper discusses the evolution of low-cost MEMS inertial system technology development for guided projectile Inertial Navigation System/Global Positioning System (INS/GPS) and high-performance inertial measurement units (IMUs). The evolution in sensors and packaging to realize performance improvement and system size reduction are presented. Recent data from the culmination of a 3-year effort to develop an 8-in3 IMU are summarized and represent the highest performance to date for an all-silicon IMU. Further investments in gun-hard silicon MEMS systems will ultimately realize IMUs that are smaller (less than 2 in3 (33 cc), higher performing (1 deg/h and less than 1 mg), and lower in cost (less than $1200 per IMU and $1500 per INS/GPS) than is achievable in any competing technology.

Subjects: MICROELECTROMECHANICAL SYSTEM (MEMS), INERTIAL NAVIGATION SYSTEMS (INS), GLOBAL POSITIONING SYSTEM (GPS), INERTIAL MEASUREMENT UNIT (IMU), COMPETENT MUNITIONS

Barbour, N.M.

Inertial Navigation Sensors

Sensors & Electronics Technology Panel, Advances in Navigation Sensors & Integration Technology. Held in London, UK; Ankara, TUR; Paris, FRA, 10/20/2003 to 10/28/2003, pp. 2-1 to 2-18. Sponsored by: North Atlantic Treaty Organization (NATO). (Draper Report no. P-4151)

Abstract: For many navigation applications, improved accuracy/performance is not necessarily the most important issue, but meeting performance at reduced cost and size is. In particular, small navigation sensor size allows the introduction of guidance, navigation, and control into applications previously considered out of reach ( e.g., artillery shells, guided bullets). In recent years, three major technologies have enabled advances in military and commercial capabilities. These are ring-laser gyros, fiber-optic gyros, and Microelectromechanical Systems (MEMS). Technology developments in these fields are described with specific emphasis on MEMS sensor design and performance. Some aspects of performance drivers are mentioned as they relate to specific sensors. Finally, predictions are made of the future applications of the various sensor technologies.

Subjects: INERTIAL NAVIGATION, SENSORS, RING LASER GYROSCOPES, OPTICAL FIBER GYROSCOPES (FIBER-OPTIC GYROSCOPES), MICROELECTROMECHANICAL SYSTEM (MEMS)

Bedrossian, N.; Pietz, J.

Momentum Dumping Using Only CMGs

Guidance, Navigation, and Control Conference and Exhibit. Held in Austin, TX., 08/11/2003 to 08/14/2003. Sponsored by: AIAA. (Draper Report no. P-4125)

Abstract: The capability to desaturate angular momentum using only angular momentum devices is demonstrated. It is shown that by appropriately maneuvering the spacecraft in a disturbance field, accumulated momentum can be removed. The momentum unloading maneuver is posed as an optimal control problem and solved with the Legendre pseudospectral method and nonlinear programming software. Resulting optimal solutions are verified via simulation.

Subjects: MOMENTUM DUMPING, CONTROL MOMENT GYROSCOPES (CMG), LEGENDRE PSEUDOSPECTRAL METHODS, ANGULAR MOMENTUM, OPTIMAL CONTROL

Boelitz, F.W.; Gatt, P.; Martin, A.A.

Launch Vehicle Wind Look Ahead Guidance for Ascent Load Management

Guidance, Navigation, and Control Conference. Held in Austin, TX, 08/11/2003 to 08/14/2003. Sponsored by: AIAA. (Draper Report no. P-4144)

Abstract: During the boost phase of ascent, winds have a significant impact on a launch vehicle's angle of attack (alpha), and can induce large structural loads on the vehicle. The current balloon-based method of collecting wind information produces wind profiles with significant uncertainty, due to the inherent time delays associated with balloon measurement procedures. This paper will describe a novel approach to measuring and managing structural loads through the combination of a Light Detection and Ranging (LIDAR) wind sensor and a control methodology named Model Predictive Control (MPC). LIDAR wind sensors can provide accurate, near-real-time wind measurements, significantly reducing wind uncertainty. MPC takes full advantage of this current wind information through a unique combination of proactive control and tuning flexibility. Descriptions of both the LIDAR sensor and MPC are included. A brief description of LIDAR sensor and MPC theory are included as well. The performance of the integrated LIDAR and MPC system will then be compared to that of the baseline controller for a wide range of wind profiles gathered from Kennedy Space Center. Simulation results have shown a 60% reduction in peak Q(alpha) relative to a contemporary control system.

Subjects: LAUNCH VEHICLES, WIND, MODEL-BASED PREDICTIVE CONTROL (MBPC), LIDAR

Borenstein, J.T.; Barnard, E.; Orrick, B.; Cheung, W.; Sundback, C.; Vacanti, J.P.

Microfabricated Biodegradable Scaffolds for Tissue Engineering of Vital Organs

Materials Research Society, Fall 2003. Held in Boston, MA, 12/01/2003 to 12/05/2003. Sponsored by: MRS. (Draper Report no. P-4146)

Abstract: Microfabrication has been demonstrated as a platform technology for the fabrication of scaffolds for tissue engineering of vital organs. The principal advantage of this technology over existing approaches is the ability to fabricate micron-scale features such as capillaries, which are critical to the function of the engineered organ construct. Biocompatible polymers such as polydimethylsiloxane (PDMS) comprise useful templates for demonstration of the technology, but a fully implantable replacement organ construct will require the use of biodegradable polymers and microfabrication techniques capable of fashioning these materials into organ scaffolds with high resolution. Earlier reports by this group described the development of microfabrication techniques capable of producing microfluidic structures for organ vasculature using the biodegradable polymer PLGA (poly(lactic-co-glycolic acid.)) In this paper, a process for the fabrication of high-resolution three-dimensional scaffolds capable of co-culture of vascular and parenchymal cells is described. Processing of these constructs requires the bonding of multiple sheets of micromachined PLGA vessel networks together with layers that comprise the parenchymal compartments of the organ, separated by thin nanoporous PLGA membranes. These three-dimensional constructs may then be seeded with the appropriate cell types and cultured to form organoid replicas. This technology will ultimately be scaled up to produce sufficient numbers of cells to replace the function of vital organs such as the kidney and liver.

Subjects: MICROFABRICATION, TISSUE ENGINEERING, ARTIFICIAL ORGANS, BIOTECHNOLOGY

Brady, T.; Buckley, S.; Dennehy, C.J.; Gambino, J.; Maynard, A.

The Inertial Stellar Compass (ISC): a Multifunction, Low-Power, Attitude Determination Technology Breakthrough

Guidance and Control Conference. 26th. Held in Breckenridge, CO, 02/05/2003 to 02/09/2003. Sponsored by: AAS. (Draper Report no. P-4101)

Abstract: The Inertial Stellar Compass (ISC) is a miniature, low-power, stellar inertial attitude determination system with an accuracy of better than 0.1 deg (1sigma) in three axes. The ISC consumes only 3.5 W of power and is contained in a 2.5-kg package. With its embedded onboard processor, the ISC provides attitude quaternion information and has Lost-in-Space (LIS) initialization capability. The attitude accuracy and LIS capability are provided by combining a wide field of view Active Pixel Sensor (APS) star camera and Microelectromechanical System (MEMS) inertial sensor information in an integrated sensor system. The performance and small form factor make the ISC a useful sensor for a wide range of missions. In particular, the ISC represents an enabling, fully integrated, microsatellite attitude determination system. Other applications include using the ISC as a "single sensor" solution for attitude determination on medium performance spacecraft and as a "bolt on" independent safe-hold sensor or coarse acquisition sensor for many other spacecraft. NASA's New Millennium Program (NMP) has selected the ISC technology for a Space Technology 6 (ST6) flight validation experiment scheduled for 2004. NMP missions, such as ST6, are intended to validate advanced technologies that have not flown in space in order to reduce the risk associated with their infusion into future NASA missions. This paper describes the design, operation, and performance of the ISC and outlines the technology validation plan. A number of mission applications for the ISC technology are highlighted, both for the baseline ST6 ISC configuration and more ambitious applications where ISC hardware and software modifications would be required. These applications demonstrate the wide range of Space and Earth Science missions that would benefit from infusion of the ISC technology.

Subjects: STELLAR INERTIAL GYROSCOPE COMPASSES, ATTITUDE DETERMINATION, MICROELECTROMECHANICAL SYSTEM (MEMS), NEW MILLENNIUM PROGRAM

Brand, T.J.; Phillips, R.E.

Foot-to-Foot Range Measurement as an Aid to Personal Navigation

Institute of Navigation Annual Meeting. 59th. Held in Albuquerque, NM, 06/23/2003 to 06/25/2003. Sponsored by: ION. (Draper Report no. P-4138)

Abstract: Ultimately, there will be times when all enhancements to GPS signal reception fail. In these situations, a number of approaches to GPS denied navigation have been proposed. These often make use of supplemental radio frequency signals, some of which actually require setting up a local radio frequency (RF) infrastructure. The navigation aid proposed here, although utilizing a radio frequency signal, is intended to be self-contained and of low power consisting of a series of foot-to-foot range measurements. A frequency generator at the waist sends signals down both legs to the feet of the user. An antenna on each boot allows the RF circuit to be completed across the distance between the feet. A phase resolver then measures the changing distance between the two feet. Our analysis shows that this scalar distance change measurement used in conjunction with micromechanical inertial instruments on each foot and combined with "zero-velocity updates" at each (or most) foot falls enables quite accurate personal navigation. The performance of an unaided inertial navigation system based on modest quality micromechanical instruments is truly poor. Our analysis shows a 2.5-km error in each horizontal direction after walking in a straight line for 10 min (2900 ft). The addition of zero velocity updates reduces this error to 60 m, predominantly in the cross-range axis. The addition of the foot-to-foot range change measurement reduces this value by another two orders of magnitude, to 0.6 m. This measurement concept is a big step toward an accurate self-contained personal navigation system. It is not dependent on external signals or ambient light. The RF could be very low power (it only has to extend over the foot-to-foot distance). As such, it should be relatively covert compared to a Doppler radar or acoustic Doppler device. There is a price to pay in terms of body-mounted hardware, but this could be mitigated by the push toward instrumented clothing.

Subjects: PERSONAL NAVIGATION, INERTIAL INSTRUMENTS

Brand, T.; Tao, Y.C.; Norris, L.

MARS Airplane Guidance and Navigation

Unmanned Unlimited Systems, Technologies & Operations Conference. Held in San Diego, CA, 09/15/2003 to 09/18/2003. Sponsored by: AIAA. (Draper Report no. P-4165)

Abstract: The Aerial Regional-scale Environmental Survey of Mars (ARES) airplane includes science objectives that place stringent requirements on the navigation system. The magnetic survey requires that the airplane fly three parallel paths 100 km long. In particular, the 1st and 3rd flight legs must be flown on a near northerly path within 5 km of each other. Without a local infrastructure to aid the navigation, this is the key design challenge. A novel technique using a combination of a high-accuracy IMU and the airplane air data system are proposed to provide sufficiently accurate knowledge to fly the required path. During the 1st leg of the science traverse, the airplane flies along a generally northerly line within the required altitude tolerance. One of the objectives of the remainder of the mission is to fly the 2nd and 3rd legs within 3 km of prescribed offsets from the initial leg. To do this well, the actual location of the groundtrack of the first leg must be known as accurately as possible. When this leg is first traversed, the navigation error is expected to be substantial, due in large part to the uncertainty existing after reentry and pullout. However, as the 180-deg turn is made to begin the 2nd leg, it is possible to observe and estimate wind speed and direction, and from that better estimate the airplane ground speed vector. At this point, one would ideally like to use a smoothing algorithm to extract the best estimate of the location of the first leg given the recently acquired knowledge of ground-relative velocity. Because real-time smoothing is impractical in this application, an alternate formulation in which the Kalman filter continuously estimates the location of several Previous Path Points (P3) on the first leg is employed. These estimates continually refine the estimate of the groundtrack of the first leg, thereby allowing the 2nd and 3rd legs to be accurately flown parallel to the first. The dynamics of the Martian wind environment will greatly influence the navigation performance, and one or two early turns prior to the first leg will be considered to enhance estimation accuracy. The guidance algorithms for this application will make significant use of the wind estimates from navigation in addition to position and velocity estimates. Specifically, the wind estimates will be used to determine the initiation of turns. If wind estimates are not used, winds can result in overshoot of the desired path for a period of time. This reduces the length of the parallel flight leg and thus diminishes the scientific value of the mission. Guidance can use the current wind estimate to determine the point at which the aircraft must begin its turn such that it reaches the parallel path in near-minimum time without overshoot. In the vertical channel, guidance will provide altitude commands to the control system such that the airplane maintains an altitude of 1.5 km above the average local terrain.

Subjects: AERIAL REGIONAL-SCALE ENVIRONMENTAL SURVEY (ARES), MARS AIRPLANE, GUIDANCE, NAVIGATION, AIR DATA SYSTEMS, INERTIAL MEASUREMENT UNIT (IMU)

Cleary, M.E.; Kolitz, S.

Variable Initiative in Optimization-Based Planning and Control Systems

AAAI Spring Symposium. Held in Palo Alto, CA, 03/24/2003 to 03/26/2003. Sponsored by: AAAI. (Draper Report no. P-4060)

Abstract: As decision algorithms become more capable, addressing more complex problems, our customers seek increasing insight into the decision process. Most fielded systems require humans in the loop, sometimes in very time- critical situations. Although heuristic decision approaches can be made understandable in relatively straight- forward ways, we have found mathematical optimization-based decision algorithms to be the most powerful approaches to a wide variety of challenges in control of real vehicles and of large, complex systems. This requires we find ways to interpret the algorithmic process and results for users. Further, the user and system should both be able to adjust their modality of interaction as needed by the changing situation. That ability to vary roles dynamically between user and system is Variable Initiative. We are investigating the use of closed-loop control approaches to this kind of interaction, with the end goal of designing computer systems that can automatically vary their initiative based on their assessment of their own, their users, and the world's state. This paper presents our approach, as well as our initial tools and results.

Subjects: OPTIMIZATION, DECISION SYSTEMS, CLOSED-LOOP SYSTEMS (FEEDBACK CONTROL), HIERARCHICAL SYSTEMS, CONTROL SYSTEMS

Davis, C.E.; Dube, C.E.; Borenstein, J.T.; Zapata, A.M.; Kang, J.M.; Nazarov, E.G.; Miller, R.A.

SPORE Biomarker Detection Using a MEMS Differential Mobility Spectrometer

Solid-State Sensors, Actuators, and Microsystems (Transducers). 12th. Held in Boston, MA, 06/08/2003 to 06/12/2003. Sponsored by: IEEE/EDS. (Draper Report no. P-4079)

Abstract: Early detection technologies permit quick characterization of a bioweapons threat and identification of a hoax that will minimize human casualties and reduce the time and financial burdens associated with containment, triage, and clean up. In this paper, we demonstrate that distinctive biological markers are present in pyrolyzed Bacillus endospore samples, and these volatile chemical signatures can be detected by differential ion mobility spectrometry (DMS). The known endospore biomarker 2,6-pyridine-dicarboxylic acid (dipicolinic acid) can be detected by our micromachined DMS device, and Bacillus spore biomarkers are detected by DMS after pyrolysis.

Subjects: MICROELECTROMECHANICAL SYSTEM (MEMS), SPECTROMETERS, ION MOBILITY, BIOLOGICAL WARFARE AGENTS

Desai, M.; Shu, L.; Mangoubi, R.

Average Connectivity Properties of Wireless Ad Hoc Networks

Wireless Communications and Networking Conference (WCNC). Held in New Orleans, LA, 03/16/2003 to 03/20/2003, Vol. 3, pp. 1528-32. Sponsored by: IEEE. (Draper Report no. P-4042)

Abstract: We consider the average radio coverage area size of a connected duster W(a,r) in a uniformly randomly deployed wireless network over a D-dimensional infinite field (D > 1), where r is the radio distance, and a the nodal deployment density. We show that (see Eq. 1) is a function (see Eq. 2) only where F(r) denotes the volume of a sphere with radius r. We provide an explicit form of WN(y) for arbitrary D as the sum of three terms, dominated by one that exhibits exponential behavior. For D = 1, we show that (see Eq. 3). Our simulations validate our 1-D solution, and show that the exponent for 2-D deployment is smaller than y.

Subjects: WIRELESS AD HOC NETWORKS, CONNECTIVITY, NODES

Desai, M.N.; Mangoubi, R.S.

Robust Gaussian and Non-Gaussian Matched Subspace Detection

Transactions on Signal Processing. Vol. 51, No. 12, 12/2003, pp. 3115-3127. Sponsored by: IEEE. (Draper Report no. P-3987-REV-A)

Abstract: We address the problem of matched filter and subspace detection in the presence of arbitrary noise and interference or interfering signals that may lie in an arbitrary unknown subspace of the measurement space. A minmax methodology developed to deal with uncertainty can also be adapted to situations where partial information on the interference or other uncertainties is available. This methodology leads to a hypothesis test sensitivity. The robust test detailed in this paper is applicable to a large class of noise density functions. In addition, generalized likelihood ratio (GLR) detectors are derived for the class of generalized Gaussian noise. The detectors are generalizations of the x2, t, and F statistics used with Gaussian noise, which are themselves motivated in a new way by the robust test. For matched-filter detection, robust test reduces to the conventional test when unlearned subspace interference is known to be absent. The results demonstrate that when compared with the conventional detector, the robust one trades off some detection performance in the absence of interference for the sake of robustness in its presence.

Subjects: GAUSSIAN NOISE (RANDOM NOISE), DETECTORS, GENERALIZED LIKELIHOOD RATIO TEST (GLRT)

Desai, M.; Mangoubi, R.

Subspace Learning and Innovation Characterization in Generalized Gaussian Noise

ASILOMAR Conference on Signals, Systems, and Computers. 37th. Held in Monterey, CA, 11/09/2003 to 11/12/2003. Sponsored by: IEEE. (Draper Report no. P-4193)

Abstract: This paper formulates the problem of maximum likelihood subspace learning and innovation characterization in the presence of generalized Gaussian noise. This approach leads to a set of necessary conditions that are a nonlinear generalization of the Gaussian eigenvalue decomposition of the sample covariance matrix. To address the innovation problem, a class of jointly generalized Gaussian random variables is introduced using a generalized correlation matrix. Necessary conditions for the maximum likelihood estimate of that matrix are derived, whose solution would permit the recovery of the innovation.

Subjects: GAUSSIAN NOISE (RANDOM NOISE), NON-GAUSSIAN, MAXIMUM LIKELIHOOD ESTIMATION, SUBSPACE DETECTORS

DiMatteo, R.; Greiff, P.; Seltzer, D.; Meulenberg, D.; Brown, E.; Carlen, E.; Kaiser, K.; Nguyen, H.; Azarkevich, J.; Baldasaro, P.; Beausang, J.; Danielson, L.; Dashiell, M.; DePoy, D.; Ehsani, H.; Topper, W.; Rahner, K.; Siergiej, R.

Micron-Gap ThermoPhotoVoltaics (MTPV)

Direct Energy Conversion, Kickoff Meeting & Workshop (DARPA, ONR, NAVSEA, NASA). Held in Las Vegas, NV, 12/09/2003 to 12/11/2003. (Draper Report no. P-4184)

Subjects: MICRON-GAP THERMOPHOTOVOLTAICS (MTPV), MICROELECTROMECHANICAL SYSTEM (MEMS), HEAT MEASUREMENT, THERMOPHOTOVOLTAICS (TPV)

Duwel, A.; Barbour, N.

MEMS Development at Draper Laboratory

Society of Experimental Mechanics (SEM) Annual Conference. Held in Charlotte, NC, 06/02/2003 to 06/04/2003. Sponsored by: SEM. (Draper Report no. P-4115)

Abstract: This paper presents the results of MEMS research and development at Draper Laboratory. These activities began at Draper by expanding traditional core technologies in guidance, navigation, and control into the MEMS arena. This focused effort led to high-performance MEMS gyros and accelerometers that could operate in applications previously considered impossible. The quest for high-performance drove the development of a state-of-the-art fabrication laboratory capable of deep, high-aspect ratio etching. In parallel, the advancement of MEMS packaging techniques, miniature electronics design, and MEMS testing capabilities enabled the success of inertial MEMS. The large infrastructure that arose from the initial MEMS activities allowed the generation of many new MEMS devices. These devices, and their specific advantages (such as extreme robustness), led to the development of advanced MEMS-based system designs that meet a wide range of market, research, and government needs. These include sensors such as multi-axis gyros and accelerometers on a single chip for commercial and military navigation, filters for wireless communications, chemical and biological sensors for medical diagnostics, microfluidics and tissue engineering for implants, and acoustic and inertial sensors for prosthetics. The ultimate realization of MEMS into mainstream applications is ongoing and is supported by system-level collaborations with the vibrant MEMS research community.

Subjects: MICROELECTROMECHANICAL SYSTEM (MEMS)

Gustafson, D.; Dowdle, J.

Deeply Integrated Code Tracking: Comparative Performance Analysis

Institute of Navigation (ION) GPS/GNSS. Held in Portland, OR, 09/09/2003 to 09/12/2003. Sponsored by: ION. (Draper Report no. P-4159)

Abstract: New algorithms for GPS code tracking have been developed recently based on deep integration concepts, nonlinear filtering methods, and extended range correlation. Hardware-in-the-loop demonstrations of Deep Integration algorithms conducted at Draper Laboratory have indicated that improvements of up to 15 dB in broadband antijam capability can be expected relative to current gain scheduled tightly-coupled tracking loops for some scenarios. These results verify earlier analytical predictions. The reported results summarized overall performance data using relatively complex scenarios (e.g., inertial aiding, full 6D, 4 or more satellites in view, guided munitions, etc.). Specific sources of improvement were not identified. Performance comparisons are inevitably scenario-dependent. With this in mind, the objective of this paper is to provide comparative performance analyses in a few simple generic scenarios with a minimum number of variable parameters and to identify and quantify the sources of improvement available through the use of Deep Integration. Three types of P-code tracking loops were considered: (1) deeply integrated, (2) fixed-gain, and (3) adaptive gain. The latter two loops are meant to represent traditional tightly-coupled systems. Broadband Gaussian jamming was assumed throughout. Performance was estimated using Monte Carlo simulation. Loss-of-lock probability was selected as the performance criterion. The results indicated that the Deeply Integrated loop consistently outperformed the other two loops in scenarios with high dynamics and/or high levels of jamming. In addition, the Deeply Integrated loop outperformed the adaptive gain loop under extended-range conditions, where the adaptive loop employed traditional flattop or linear extended-range detectors shapes.

Subjects: CODE TRACKING, PERFORMANCE ANALYSIS, GLOBAL POSITIONING SYSTEM (GPS), INTEGRATION, MONTE CARLO METHOD

Hagelstein, P.L.; Sinha, K.P.; Meulenberg, A.; DiMatteo, R.S.; Fonstad, C.G.

Nearly-Isentropic Energy Conversion with Quantum Excitation Transfer

Research Lab for Electronics (RLE) Progress Report, N145, 09/05/2003, pp. 29-1 - 29-4. Sponsored by: MIT Research Lab for Electronics. (Draper Report no. P-4168)

Subjects: ENERGY CONVERSION, EXCITATION, ENTROPY

Hall, R.A.; Lowry, N.C.

A Cost Function for Bang-Off-Bang Control of Axisymmetric Spacecraft

Space Flight Mechanics Meeting. 13th. Held in Ponce, Puerto Rico, 02/09/2003 to 02/12/2003. Sponsored by: AAS/AIAA. (Draper Report no. P-4055-REV-A)

Abstract: Cost functions representing propellant usage for bang-off-bang attitude control of axisymmetric spacecraft is introduced. Cost functions are defined for Euler axis rotations, "torque-free" rotations, and three-pulse rotations, which are three differing rotational trajectories to achieve a vehicle rotational reorientation. It is demonstrated that use of the cost function can result in significant savings by predicting the best trajectory to achieve a commanded rotational maneuver.

Subjects: COST FUNCTIONS, PROPELLANTS, ATTITUDE CONTROL

Hall, R.A.; Lowry, N.C.; Ghorbel, F.

Three-Pulse Minimal Fuel Rotations of Axisymmetric Spacecraft Using Reaction Control Thrusters

American Control Conference (ACC). Held in Denver, CO, 06/04/2003 to 06/06/2003, Vol. 2, pp. 1128-1133. Sponsored by: IEEE. (Draper Report no. P-4056-REV-A)

Abstract: Spacecraft employing reaction control thrusters for attitude control typically utilize a bang-off-bang algorithm to complete rotational maneuvers. This approach ideally commands only two pulses, one to initiate the rotation and one to terminate it. These algorithms generally tend to provide a fuel minimal solution provided a rest-to-rest maneuver, but can be suboptimal if either initial or final rate is nonzero. A three-pulse algorithm for axisymmetric spacecraft is introduced that can provide decreased propellant usage for rotations with nonzero initial conditions.

Subjects: REACTION CONTROL SYSTEMS (RCS), FUEL DEPLETION, SPACECRAFT

Hammett, R.C.; Babcock, P.S.

Achieving 10(-9) Dependability with Drive-by-Wire Systems

Society of Automotive Engineers (SAE) World Congress. Held in Detroit, MI, 03/03/2003 to 03/06/2003. Sponsored by: SAE. (Draper Report no. P-4027)

Abstract: The automotive industry is moving ahead to introduce drive-by-wire (DBW) electronic systems to replace mechanical controls and linkages that have changed little since cars were first introduced. Electronic drive-by-wire systems offer enormous potential to improve vehicle performance and safety, but matching the dependability of simple mechanical components with electronics will be a challenge. Highly dependable electronic controls require a fault-tolerant approach with both a primary and a backup system as a minimum. Aircraft fly-by-wire systems go beyond this, using triple and quadruple redundant electronics to tolerate more than one failure during the same flight. Automobile drive-by-wire must also provide some capability to allow the car to be driven safely to a repair facility after a failure occurs. This paper examines some possible drive-by-wire systems architectures, presents a mathematical analysis of the predicted dependability (expressed as the probability the system will fail in a given time period) of these alternatives, and investigates the impact of how the vehicle is operated and maintained on its dependability. Architectural alternatives considered include both dual and triple redundant systems. The mathematical analysis builds on techniques developed to analyze aircraft systems using Markov reliability modeling. The uncertainty associated with such predictions will be discussed along with comparisons to acceptable risk levels for other established technologies.

Subjects: AUTOMOTIVE APPLICATIONS, DRIVE-BY-WIRE SYSTEMS

Hammett, R.

Fault-Tolerant Avionics Systems

Digital Avionics Systems Conference. Held in Indianapolis, IN, 10/12/2003 Sponsored by: IEEE. (Draper Report no. P-4171)

Subjects: TUTORIALS, FAULT-TOLERANT SYSTEMS, AEROSPACE SYSTEMS, FAILURE DETECTION, FAULT-TOLERANT COMPUTING, AVIONICS

Hammett, R.

Flight-Critical Distributed Systems - Design Considerations

Aerospace and Electronic Systems Magazine, Vol. 18, No. 6, June, 2003, pp. 30-36. Sponsored by: IEEE. (Draper Report no. P-3994-REV-B)

Abstract: With the proliferation of so-called "smart" components and the availability of small, low-cost, and high-speed data networks, avionics that have traditionally been centralized are becoming distributed. A distributed approach offers many potential benefits, such as reduced development time and cost, simplified system installation, increased flexibility for system expansion or modifications, and greater reuse of proven components. The distributed approach can also reduce the risk associated with design errors by splitting complex hardware and software into more manageable components. However, distributed systems also introduce new challenges in meeting real-time deadlines and providing fault tolerance. The automotive industry is addressing these challenges with the development of distributed, drive-by-wire systems, and the adaptation of these to avionic applications looks promising. In developing these new distributed systems, there are many fundamental system design considerations, including time or event-triggered data communication, distributed or centralized data network control need and method for time-synchronization of distributed components, topology, amount of redundancy to provide fault tolerance, extent that component software is tailored to the installation, and the role of overall system-level design and analysis as compared to a plug-and-play approach. This paper examines these design considerations and identifies the strengths and weaknesses of each. Emerging automotive drive-by-wire alternatives are compared for application to aerospace systems. This paper is based on a Draper Laboratory-sponsored effort to look at flight-critical distributed systems and to evaluate emerging hardware and software for building them.

Subjects: DISTRIBUTED SYSTEMS, FLIGHT-CRITICAL SYSTEMS, FAULT TOLERANCE, DATA COMMUNICATIONS

Hammett, R.; Schwartz, G.; Smithgall, W. T.

Preventing Data Pollution in the Space Shuttle Cockpit

Digital Avionics Systems Conference. Held in Indianapolis, IN, 10/12/2003 to 10/14/2003, pp. 1.B.3-1. Sponsored by: IEEE / AIAA. (Draper Report no. P-4094)

Subjects: SPACE SHUTTLES, COCKPITS, DATA POLLUTION, FAULT-TOLERANT SYSTEMS, AVIONICS, DISPLAY COMPUTER SYSTEMS

Harrison, J.

A Collaborative Modeling & Simulation Infrastructure

2003 Software Virtual Product Development Conference. Held in Dearborn, MT, 10/13/2003 to 10/15/2003. Sponsored by: MSC Software. (Draper Report no. P-4175)

Subjects: MODELING, DRAPER LABORATORY SIMULATION FRAMEWORK, COMMERCIAL OFF THE SHELF (COTS)

Homer, M.

A Quantitative Approach for Determining the Level and Sophistication of Automation in Unmanned Vehicles

Unmanned Systems Symposium & Exhibition. Held in Baltimore, MD, 07/15/2003 to 07/17/2003. Sponsored by: Association for Unmanned Vehicle Systems International (AUVSI). (Draper Report no. P-4069)

Abstract: A key question designers of unmanned vehicles face is: To what degree and level of sophistication should functions be automated? With each new vehicle project, an answer must be found. Some major influences on the decision are mission requirements and uncertainties, operating environment, communications constraints, the physical capability of the vehicle, and sensor performance. This paper presents an analytical method that helps practitioners find a solution while taking into account such factors. The approach recasts the problem into a trade study linking functional requirements placed on the automation to operational performance and cost. Drawing upon prior work, the discussion first frames the problem by providing workable definitions for degree of automation and its level of sophistication. A blueprint for conducting investigations follows including an approach to building quantitative models and a technique for running simulations. Throughout, a real-world case study complete with simulation results provides illustration and demonstrates the method's utility.

Subjects: UNMANNED VEHICLES, AUTOMATION SOPHISTICATION

Houston, K.M.; McGaffigan, D.P.

Spectrum Analysis Techniques for Personnel Detection Using Seismic Sensors

Unattended Ground Sensor Technologies and Applications. 5th. Held in Orlando, FL, 04/21/2003 to 04/25/2003, pp. 162-173. Sponsored by: International Society for Optical Engineering (SPIE). (Draper Report no. P-4051-REV-A)

Abstract: There is a general need for improved detection range and false alarm performance for seismic sensors used for personnel detection. In this paper we describe a novel footstep detection algorithm that was developed and run on seismic footstep data collected at the Aberdeen Proving Ground (APG) in December 2000. The initial focus was an assessment of achievable detection range. The conventional approach to footstep detection is to detect transients corresponding to individual footfalls. We feel this is an error-prone approach. Because many real-world signals unrelated to human locomotion look like transients, transient-based footstep detection will inevitably either suffer from high false alarm rates or will be insensitive. Instead, we examined the use of spectrum analysis on envelope-detected seismic signals and have found the general method to be quite promising, not only for detection, but also for discrimination against other types of seismic sources. In particular, gait patterns and their corresponding signatures may help discriminate between human intruders and animals. In the APG data set, mean detection ranges of 64 m (at PD= 50%) were observed for normal walking, significantly improving on ranges previously reported. For running, mean detection ranges of 84 m were observed. However, stealthy walking (creeping) remains a considerable problem. Even at short ranges (10 m), in some cases the detection rate was less than 50%. In future efforts, additional data sets for a range of geologic and environmental conditions should be acquired and analyzed. Improvements to the detection algorithms are possible, including estimation of direction of travel and the number of intruders.

Subjects: SPECTRUM ANALYSIS, SEISMIC SENSORS

Jang, J.W.; Bedrossian, N.; Wallace, J.; Zeigler, P.

A Web-Enabled Space Station Simulation Development & Analysis Tool (eSim)

Modeling and Simulation Technologies. Held in Austin, TX, 08/11/2003 to 08/14/2003. Sponsored by: AIAA. (Draper Report no. P-4140)

Abstract: eSim was developed by Draper-Houston to provide a distributed analysis and simulation capability. The Draper Station Analysis Tool (DSAT) is used to solve the problem of the integrated verification of the International Space Station (ISS) guidance, navigation, and control (GN&C) system, while meeting demanding schedules and providing confidence in risk estimates. Its functional capabilities include static, frequency domain and time domain analysis. eSimDSAT allows users to access the fully functional version of DSAT via the internet from anywhere in the world. It is believed that eSimDSAT is the first web-enabled Space Station simulation and analysis tool to be reported in the literature.

Subjects: SPACE STATIONS; SIMULATION; GUIDANCE, NAVIGATION, AND CONTROL (GN&C); DRAPER STATION ANALYSIS TOOL (DSAT); EXTERNAL ENVIRONMENT SIMULATOR (ESIM)

Jang, J.W.; Lee, A.; Bedrossian, N.; Spanos, P.

Design of Robust Nash Game Theoretic Controllers with Time Domain Constraints

American Control Conference (ACC). Held in Denver, CO, 06/04/2003 to 06/06/2003, Vol. 6, pp. 5363-5368. Sponsored by: IEEE. (Draper Report no. P-4109)

Abstract: The Nash differential game theory does not directly handle the specifications on either closed-loop time-domain constraints or model uncertainties. An inverse solution procedure, which converts the Nash game theoretic controller design task to a constrained optimization problem, can take account of these control design requirements directly. In this paper, the authors propose a constrained robust Nash game controller design procedure for uncertainty systems with time-domain constraints.

Subjects: GAME THEORY, UNCERTAINTY, TIME DOMAIN, CONSTRAINED OPTIMIZATION

Jang, J.W.

Draper Station Analysis Tool (DSAT)

Astrodynamics Specialists Conference. Held in Big Sky, MT, 08/03/2003 to 08/07/2003. Sponsored by: AAS/AIAA. (Draper Report no. P-4132)

Abstract: A very low-cost, high-throughput, scalable, plug-and-play, commercial-off-the-shelf (COTS) based simulation development and analysis platform for use in design and verification of complex dynamical systems is reviewed. The tool has been in continuous use over the past 5 years for integrated verification of the International Space Station (ISS) guidance, navigation, and control (GN&C) systems, while meeting demanding schedules and providing confidence in risk estimates. Its modular design accommodates parameter or architecture modifications. Its unique features include automated simulation generation, verification analysis process, and results documentation. Its functional capabilities include analytic, frequency domain, and time domain analysis. The tool's full functional capabilities are also accessible via the Web (http://www.isc.draper.com/esim).

Subjects: DRAPER STATION ANALYSIS TOOL (DSAT); GUIDANCE, NAVIGATION, AND CONTROL (GN&C); INTERNATIONAL SPACE STATION (ISS)

Jang, J.W.

Multivariable Flex Model Reduction

Astrodynamics Specialist Conference. Held in Big Sky, MT, 08/03/2003 to 08/07/2003. Sponsored by: AAS/AIAA. (Draper Report no. P-4130)

Abstract: To analyze large dimensional flex models such as the International Space Station (ISS) requires substantial computational effort. The popular Balanced Truncation (BT) method has been frequently used to reduce computational load. However, the BT method often requires extensive computational effort and sometimes lacks numerical robustness. In this paper, an innovative model reduction technique, which converts a flex model into a "tridiagonal modal form" and then truncates the resulting model based on a multivariable Modal Gain Factor approach, is presented. The proposed technique takes less computational effort and is numerically stable for ISS flex models. Comparisons with the BT method will be presented for various ISS assembly stage flex models.

Subjects: INTERNATIONAL SPACE STATION (ISS), FLEX MODEL, DIMENSIONAL SYSTEMS

Jang, J.W.; Lee, A.; Bedrossian, N.; Spanos, P.

Robust Momentum Manager Design for the Space Station with Momentum Capacity Constraint

Modeling and Simulation Technologies. Held in Austin, TX, 08/11/2003 to 08/14/2003. Sponsored by: AIAA. (Draper Report no. P-4141)

Abstract: An innovative methodology to design a robust Control Moment Gyroscope (CMG) momentum manager for the International Space Station is developed. The robust design requirements are to be met with maximum capacity, 10,500 ft-lb-s, of the 3-CMG system in the presence of uncertainties. Unlike most other momentum manager designs, which use either LQR or u-synthesis technique, the proposed methodology is based on the Nash differential game theory. An inverse solution procedure recasts the design task to a constrained optimization problem. Design examples are provided to demonstrate the practicability of the proposed methodology.

Subjects: SPACE STATIONS, CONTROL MOMENT GYROSCOPES (CMG), MOMENTUM MANAGEMENT, GAME THEORY

Kaazempur-Mofrad, M.R.; Borenstein, J.T.; Hartman, L.M.; Cheung, W.S.; Weinberg, E.J.; Shin, M.; Sevy, A.; Vacanti, J.P.

Vascularized Tissue Engineering of Vital Organs: Design, Computational Modeling, and Functional Testing

Northeast Bioengineering Conference. 29th. Held in Newark, NJ, 03/22/2003 to 03/23/2003. Sponsored by: IEEE/EMBS. (Draper Report no. P-4108A)

Abstract: We present a computational algorithm for simulation of blood flow and rheology in microcirculation. This computational model is utilized to design fractal microvascular networks that mimic the key features of vital organ's blood supply. Using microfabrication/polymer processing technologies, these designed microvascular networks are replica molded to generate patterned biopolymer films, which are then stacked to form alternating vascular and parenchymal compartments. As our preliminary functional tests demonstrate, this approach is promising to produce viable liver and kidney tissues.

Subjects: TISSUE ENGINEERING

Kasparian, F.J.; Beilin, S.Q.; Turney, D.S.

Ruggedized PC/104-Plus PowerPC Processor Card for Avionics

Digital Avionics Systems Conference (DASC). Held in Indianapolis, IN, 10/12/2003 to 10/16/2003, Vol. 2, pp. 6.C.3/1-6.C.3/8. Sponsored by: IEEE/AIAA. (Draper Report no. P-4166)

Abstract: A ruggedized PowerPC Processor card was designed to meet a PC/104-Plus form factor. Because this card was designed to be a generic "motherboard" for many applications, the PC/104-Plus form factor was chosen for its small size, enabling this board to be used almost anywhere. The PowerPC was chosen as the processor for its wide use in the industry, the large number of supporting COTS (commercial-off-the-shelf) development tools, significant processor throughput, and a direct replacement to a radiation-tolerant part. The small board size required some innovative packaging techniques: micro-via technology, many signal layers and board material. This caused the board thickness to exceed the recommended form factor, but longer pins in the thru connectors as well as Arlon Thermount for the board aided in rectifying the problem. A combination of board thickness, frame support, and component selection were used to meet the acceleration load requirements. Processors running at high speeds tend to dissipate large amounts of heat. To remove the heat from the board, the side frames once again were called into use. The board is designed to operate in a standard convection-cooled environment. An additional connector was added to the board to provide a high-speed local bus connection to a reconfigurable input/output (I/O) card, as well as to a PCI (peripheral component interconnect) interface. Providing these two interface mechanisms to I/O cards allow COTS PCI cards to be utilized, in addition to our high-speed custom reconfigurable I/O card. This flexible architecture allows the I/O demands of almost any system to be met.

Subjects: POWERPC PROCESSOR, PC/104-PLUS, AVIONICS

Kim, E.S.; Kaazempur-Mofrad, M.R.; Borenstein, J.T.; Vacanti, J.P.; Kamm, R.D.

Design of a Single Capillary-Parenchymal Co-Culture Bioreactor Using a Self-Assembling Peptide Membrane

Computational Fluid and Solid Mechanics. 2nd. Held in Cambridge, MA, 06/17/2003 to 06/20/2003. Sponsored by: MIT. (Draper Report no. P-4087)

Abstract: A bioreactor is designed and fabricated for the co-culture of endothelial and hepatic parenchymal cells. The device provides a structured environment mimicking the in vivo characteristics of a single capillary and the adjacent tissue. The bioreactor consists of two cell-scale fluid channels separated by a biocompatible thin porous membrane made of self-assembling oligopeptide gel. Analytic and computational modeling techniques were used to investigate the fluid flow and mass transfer characteristics and aid in design of the bioreactor.

Subjects: TISSUE ENGINEERING, MICROELECTROMECHANICAL SYSTEM (MEMS)

Kondoleon, A.

Development of Alternate Sources of Hemispherical Wheels for the 16 PIGA MOD-G (Interim Findings)

Joint Navigation Conference (JNC). 28th. Held in Las Vegas, NV, 04/14/2003 to 04/17/2003. (Draper Report no. P-4121)

Subjects: 16 PIGA, MINUTEMAN III, HEMI-WHEELS

Lane, P.A.; Bernius, M.; DeMello, J.C.; Fletcher, R.B.