Northrop Grumman (Germany)

OBJECTIVE: To examine trends in the rates of hypertensive disorders in pregnancy and compare the rates of severe obstetric complications for delivery hospitalizations with and without hypertensive disorders. METHODS: We performed a cross-sectional study using the 1998-2006 Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project. Logistic regressions and population-attributable fractions were used to examine the effect of hypertensive disorders on severe complications. RESULTS: The overall prevalence of hypertensive disorders among delivery hospitalizations increased significantly from 67.2 per 1,000 deliveries in 1998 to 81.4 per 1,000 deliveries in 2006. Compared with hospitalizations without any hypertensive disorders, the risk of severe obstetric complications ranged from 3.3 to 34.8 for hospitalizations with eclampsia/severe preeclampsia and from 1.4 to 2.2 for gestational hypertension. The prevalence of hospitalizations with eclampsia/severe preeclampsia increased moderately from 9.4 to 12.4 per 1,000 deliveries (P for linear trend <0.001) during the period of study. However, these hospitalizations were associated with 38% of hospitalizations with acute renal failure and 19% or more of hospitalizations with ventilation, disseminated intravascular coagulation syndrome, pulmonary edema, puerperal cerebrovascular disorders, and respiratory distress syndrome. Overall, hospitalizations with hypertensive disorders were associated with 57% of hospitalizations with acute renal failure, 27% of hospitalizations with disseminated intravascular coagulation syndrome, and 30% or more of hospitalizations with ventilation, pulmonary edema, puerperal cerebrovascular disorders, and respiratory distress syndrome. CONCLUSION: The number of delivery hospitalizations in the United States with hypertensive disorders in pregnancy is increasing, and these hospitalizations are associated with a substantial burden of severe obstetric morbidity. LEVEL OF EVIDENCE: III.

Capability Maturity Model IntegrationSM (CMMI) has rapidly become a preferred means of improving organizational processes in industry and government. Building on a decade of work with process improvement models, including the Capability Maturity Model® (CMM®) for Software and the Systems Engineering Capability Model, a team of over two hundred engineering and process improvement experts worked for three years to create this broader, more agile instrument for guiding, integrating, and appraising improvement activities. CMMI provides a single, integrated framework for improving processes throughout an organization, enhancing the quality and efficiency of the organization as a whole.The CMMI Product Suite is rich in detail and guidance, but correspondingly large and somewhat complex. The sheer volume of information it presents can seem overwhelming. CMMI Distilled reduced that complexity with a fresh and approachable introduction to the key elements of CMMI and integrated process improvement.This new edition of CMMI Distilled, updated for CMMI version 1.1, includes more material in layman's language to meet a wider variety of reader's needs, but has not lost any of the technical content that made the first edition so successful. Written for those new to model-based process improvement, it also offers insights that can help even battle-scarred process improvement veterans and experienced systems, software and quality engineers perform better. CMMI® Distilled, Second Edition is especially appropriate for executives and managers who need to understand why process improvement is valuable, why CMMI is a tool of choice, and how to maximize the return on their efforts and investments.The three authors have been involved with CMMI since its inception, and they bring a wealth of their own experience and knowledge to this book. They highlight the pitfalls and short cuts that are all too often learned by costly experience. Above all, they provide a context for understanding why CMMI is the fastest growing process improvement framework in the world. 0321186133B06272003

A chain of four Tm-doped fibers amplified a single-frequency, 2040 nm diode laser to 608 W with M(2)=1.05+/-0.03, limited by available pump power. Stimulated Brillouin scattering limits were investigated by splicing different lengths of passive fiber to the output of the final amplifier stage. Integrated rms phase noise above 1 kHz was less than lambda/30, suggesting the possibility of further scaling via coherent beam combining. To our knowledge, this is the highest power obtained from any single-frequency, single-mode fiber laser.

The goal of the DARPA Shaped Sonic Boom Demonstration (SSBD) Program was to demonstrate for the first time in flight that sonic booms can be substantially reduced by incorporating specialized aircraft shaping techniques. Although mitigation of the sonic boom via specialized shaping techniques was theorized decades ago, until now, this theory had never been tested with a flight vehicle subjected to actual flight conditions in a real atmosphere. The demonstrative success, which occurred on 27 August 2003 with repeat flights in the supersonic corridor at Edwards Air Force Base, is a critical milestone in the development of next generation supersonic aircraft that could one day fly unrestricted over land and help usher in a new era of time-critical air transport. Pressure measurements obtained on the ground and in the air confirmed that the specific modifications made to a Northrop Grumman F-5E aircraft not only changed the shape of the shock wave signature emanating from the aircraft, but also produced a flat-top signature whose shape persisted, as predicted, as the pressure waves propagated through the atmosphere to the ground. This accomplishment represents a major advance towards reducing the startling and potentially damaging noise of a sonic boom. This paper describes the evolution of the SSBD program, including the rationale for test article selection, and provides an overview of the history making accomplishments achieved during the SSBD effort, as well as, the follow-on NASA Shaped Sonic Boom Experiment (SSBE) Program, whose goal was to further evaluate the characteristics and robustness of shaped boom signatures.

This article gives a brief overview of the common vacuum electronic tube amplifiers used in high-power transmitters. Only three types of devices [travelling wave tubes (TWTs) including helix and coupled-cavity types, microwave power modules (MPMs), and klystrons] are covered, with emphasis on the recent advance in the millimeter-wave band.

In robotics and video games, one often discretizes continuous terrain into a grid with blocked and unblocked grid cells and then uses a path‐planning algorithms to find a shortest path on the resulting grid graph. This path, however, is typically not a shortest path in the continuous terrain. In this overview article, we discuss a path‐planning methodology for quickly finding paths in continuous terrain that are typically shorter than shortest grid paths. Any‐angle path‐planning algorithms are variants of the heuristic path‐planning algorithm A* that find short paths by propagating information along grid edges (like A*, to be fast) without constraining the resulting paths to grid edges (unlike A*, to find short paths).

We propose a new methodology for explaining the predictions of black box classifiers. We use the motivating paradigm that predictive performance is of primary importance but human analysts (e.g., in fraud detection) desire a classifier's predictions to be augmented with useful explanations. To be truly general and principled, we derive a scoring system for finding explanations based on formal requirements. In this system, the explanations are assumed to take the form of simple logical statements. We derive an efficient Monte Carlo algorithm to find explanations for black box classifiers with finite sample guarantees. The methodology is then applied to interesting examples in facial recognition and credit data.

Northrop Grumman, LITEF is developing MEMS (micro-electro-mechanical systems) based Inertial Measurement Units (IMU) for future attitude and heading reference systems (AHRS) with a target accuracy of 5 deg/h for the gyroscopes and 2.5 mg for the accelerometers. Within the technology development phase, prototype single axis gyroscopes have been realized and extensively tested for effects including temperature, acoustic and vibration sensitivities. These devices employ micro-machined all-silicon gyroscope sensor chips processed with deep reactive ion etching (DRIE). Silicon fusion bonding ensures pressures smaller than 3middot10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> mbar. Sophisticated analog electronics and digital signal processing condition the capacitive pick-off signals and realize full closed loop operation. The current results with overall bias error smaller than 2 deg/h to 5 deg/h, scale factor error <1200 ppm, measurement range >1000 deg/s and angular random walk <0.4 radic/vh indicate that stable production of 5 deg/h gyroscopes is realistic. The fabrication technology for capacitive, pendulous accelerometer chips is based on that used for the gyros with only an increase in the enclosed pressure to obtain overcritical damping. Pulse width modulation (PWM) within a digital control loop is used to realize closed loop operation. Accelerometer chips have been tested over temperature with a residual bias error <2.0 mg and a scale factor error <1400 ppm. These sensor chips have been integrated into an IMU whereby the power budget and size of the sensor electronics have been optimized. In this paper the salient features of the gyro and accelerometer designs are presented together with an overview of the IMU system architecture. Measurement results, with a focus on environmental characteristics and robustness, are included.

This paper presents two origami inspired concepts for sunshields for a deployable X-ray space telescope. Analytical models of the fold layout and sunshield deployment have been derived, and these models have been used to match the sunshield design to a set of geometric constraints. To validate the design, a proof-of-concept physical model of the optimized analytical design was constructed at 1:10 scale.

&lt;div class="htmlview paragraph"&gt;A number of technology breakthroughs in the past ten years rekindled the concept of a more-electric aircraft. High-power solid-state switching devices, electrohydro-static actuators (EHAs), electromechanical actuators (EMAs), and high-speed generators are just a few examples of component developments. These developments have made dramatic improvements in properties such as weight, size, power, and cost. However, these components cannot be applied piecemeal. A complete, and somewhat revolutionary, system design approach was needed to exploit the benefits that a more-electric aircraft can provide. Traditional-mounted auxiliary drives, and bleed air extraction will disappear, to be replaced with integral engine starter/generators and electrically driven actuators and pumps.&lt;/div&gt; &lt;div class="htmlview paragraph"&gt;A five-phase Power &lt;u&gt;Ma&lt;/u&gt;nagement and &lt;u&gt;D&lt;/u&gt;istribution System for a &lt;u&gt;M&lt;/u&gt;ore-&lt;u&gt;E&lt;/u&gt;lectric Aircraft (MADMEL) program was awarded by the Air Force to Northrop/Grumman Military Aircraft Division in September 1991. The objective of the program is to design, develop, and demonstrate an advanced electrical power generation and distribution system for a More-Electric Aircraft (MEA). The MEA emphasizes the use of electrical power in place of hydraulics, pneumatic, and mechanical power to optimize the performance and life cycle cost of the aircraft. This paper presents an overview of the MADMEL program and a top-level summary of the program results, development and test of major components to date. In Phase I and Phase II studies, the electrical load requirements were established and the electrical power system architecture was defined for both near-term (NT-year 1996) and far-term (FT-year 2003) MEA application. The detailed design and specification for the Electrical Power System (EPS), its interface with the Vehicle Management System, and the test set-up were developed under Phase III. Phase IV, fabrication and testing of the subsystem level hardware, has been completed. The overall system level integration and testing, Phase V, is scheduled to be completed by September 1999.&lt;/div&gt;

For the first time in human history, technologies have matured sufficiently to enable a mission capable of discovering and characterizing habitable planets like Earth orbiting sunlike stars other than the Sun. At the same time, such a platform would enable unique science not possible from ground-based facilities. This science is broad and exciting, ranging from new investigations of our own solar system to a full range of astrophysics disciplines. The Habitable Exoplanet Observatory, or HabEx, is one of four studies currently being undertaken by NASA in preparation for the 2020 Astrophysics Decadal Survey. HabEx has been designed to be the Great Observatory of the 2030s, with community involvement through a competed and funded Guest Observer (GO) program. This interim report describes the HabEx baseline concept, which is a space-based 4-meter diameter telescope mission concept with ultraviolet (UV), optical, and near-infrared (near-IR) imaging and spectroscopy capabilities. More information on HabEx can be found at https://www.jpl.nasa.gov/habex

The roadmap laid out in the CFD Vision 2030 document [1] suggests that a decision to move away from RANS research needs to be made in the current timeframe (around 2020). This paper outlines industry requirements for improved predictions of turbulent flows and the cost-barrier that is often associated with reliance on scale resolving methods. Capabilities of RANS model accuracy for simple and complex flow fields are assessed, and modeling practices that degrade predictive accuracy are identified. Suggested research topics are identified that have the potential to improve the applicability and accuracy of RANS models. We conclude that it is important that some part of a balanced turbulence modeling research portfolio should include RANS efforts.

In this paper, recent work on pushing InP HEMT amplifier technology to 850 GHz is reported. In particular, we have demonstrated on-wafer gain at this frequency. To our knowledge, this is the first time gain has been reported at this frequency. This achievement is possible by transistor scaling, frontside and backside feature scaling and detailed transistor modeling and design.

*† ‡ Unmanned Air Vehicles (UAVs) are currently not authoriz ed by the Federal Aviation Administration to operat e freely within the National Airspace (NAS) due to the lack of an onboard system capable of providing an “equivalent level of safety ” (ELOS) to manned aircraft regarding the ability to “sense and avoid ” (SAA) other aircraft. This paper describes the effort s t o integrate component technologies developed for electro -optical (EO) camera -based aircraft detection system into a SAA capability for High Altitude Long Endurance (HALE) UAVs such as Global Hawk and Predator B . The major technology gap preventing EO m easurements from be ing directly us ed with a collision avoidance system is the lack of range information. In this paper, the authors investigate the feasibility of estimating the range and velocity of other air t raffic by performing a small self -maneuver . The authors explore the performance of ra nge estimation while subject to the ownship maneuverability and other mission and operational constraints such as staying within the assigned Air Tra ffic Control (ATC) corridor . Furthermore, the authors investigat e the effects of range estimat ion errors on the collision avoidance performance .

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;Once limited by insufficient accuracy, the off-the-shelf industrial robot has been enhanced via the integration of secondary encoders at the output of each of its axes. This in turn with a solid mechanical platform and enhanced kinematic model enable on-part accuracies of less than +/−0.25mm. Continued development of this enabling technology has been demonstrated on representative surfaces of an aircraft fuselage. Positional accuracy and process capability was validated in multiple orientations both in upper surface (spindle down) and lower surface (spindle up) configurations. A second opposing accurate robotic drilling system and full-scale fuselage mockup were integrated to simulate doubled throughput and to demonstrate the feasibility of maintaining high on-part accuracy with a dual spindle cell.&lt;/div&gt;&lt;/div&gt;

NGES reports the development of a novel transistor structure based on a GaN super-lattice channel with a 3D gate, named the SLCFET (Super-Lattice Castellated Field Effect Transistor). Transistor measurements provided median values of I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MAX</inf> >2.7 A/mm, V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">PINCH</inf> = −8V, with R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</inf> =0.41 Ω-mm and C <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OFF</inf> =0.19 pF/mm, for an RF switch FOM of F <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CO</inf> =2.1 THz.

In the following paper, we present an industry perspective of inertial sensors for navigation purposes driven by applications and customer needs. Microelectromechanical system (MEMS) inertial sensors have revolutionized consumer, automotive, and industrial applications and they have started to fulfill the high end tactical grade performance requirements of hybrid navigation systems on a series production scale. The Fiber Optic Gyroscope (FOG) technology, on the other hand, is further pushed into the near navigation grade performance region and beyond. Each technology has its special pros and cons making it more or less suitable for specific applications. In our overview paper, we present latest improvements at NG LITEF in tactical and navigation grade MEMS accelerometers, MEMS gyroscopes, and Fiber Optic Gyroscopes, based on our long-term experience in the field. We demonstrate how accelerometer performance has improved by switching from wet etching to deep reactive ion etching (DRIE) technology. For MEMS gyroscopes, we show that better than 1°/h series production devices are within reach, and for FOGs we present how limitations in noise performance were overcome by signal processing. The paper also intends a comparison of the different technologies, emphasizing suitability for different navigation applications, thus providing guidance to system engineers.

It is generally assumed that correcting chromatic aberrations in imaging requires multiple optical elements. Here, we show that by allowing the phase in the image plane to be a free parameter, it is possible to correct chromatic variation of focal length over an extremely large bandwidth, from the visible (Vis) to the longwave infrared (LWIR) wavelengths using a single diffractive surface, i.e., a flat lens. Specifically, we designed, fabricated and characterized a flat, multi-level diffractive lens (MDL) with a thickness of ≤ 10µm, diameter of ∼1mm, and focal length of 18mm, which was constant over the operating bandwidth of λ=0.45µm (blue) to 15µm (LWIR). We experimentally characterized the point-spread functions, aberrations and imaging performance of cameras comprised of this MDL and appropriate image sensors for λ=0.45μm to 11μm. We further show using simulations that such extreme achromatic MDLs can be achieved even at high numerical apertures (NA=0.81). By drastically increasing the operating bandwidth and eliminating several refractive lenses, our approach enables thinner, lighter and simpler imaging systems.

This article discusses control techniques of the current-controlled and voltage-controlled BICs in a hybrid ac/dc microgrid. We draw the following conclusions: 1) The current-controlled BIC is simple and easy to deploy. It is easy to decouple its active and reactive power control and has few circulation problems. However, it highly relies on ac bus voltage support and often has poor operating characteristics in a weak grid. 2) The voltage-controlled BIC usually has its own voltage reference and can operate with or without the support of ac side bus bars. It also depends little on PLLs. Therefore, from the perspective of the system stability, it is more suitable than current-controlled BICs for hybrid microgrids when in islanded mode or connected to a weak grid. Nonetheless, power coupling and parallel circulation problems are hard to avoid. 3) There is no one-size-fits-all solution. The best control strategy will depend on the application requirements and topology selections. 4) Further development of BICs can include the rated capacity selection, series/parallel control strategy design, reactive power coordination, islanding detection techniques, and fault ride-through technology.

The application of a constrained receding horizon control technique to stabilise an indoor vectored-thrust flight experiment, known as the Caltech ducted fan, is given. The receding horizon control problem is formulated as a constrained optimal control problem and solved in real time with an efficient, computational method that combines nonlinear control theory, B-spline basis functions, and nonlinear programming. Characteristic issues, including non-zero computational times, convergence properties, choice of horizon length and terminal cost are discussed. The study validates the applicability of real-time receding horizon control for constrained systems with fast dynamics.