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Search Results: 1 - 10 of 4429 matches for " Kenneth Sobel "
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Simple Adaptive Delta Operator Aircraft Flight Control for Accommodation of Loss of Control Effectiveness  [PDF]
Alfredo Cano, Kenneth Sobel
Engineering (ENG) , 2016, DOI: 10.4236/eng.2016.84016
Abstract: A new proof for stability of delta operator simple adaptive control is presented in terms of a set of Linear Matrix Inequalities (LMIs). The paper shows how to design a feedforward gain to satisfy the LMIs over a polytope of loss of control effectiveness failures. The MATLAB Robust Control Toolbox is used to find the feedforward gain with the smallest norm that satisfies the LMIs. Examples are presented of the F/A-18 aircraft and the Innovative Control Effectors (ICE) tailless aircraft that show the design of a feedforward gain for a loss of control effectiveness in any one control effector. The designs use a fixed eigenstructure assignment controller for an inner loop augmented with the simple adaptive controller. Simulations of both aircraft include simultaneous loss of control effectiveness failure and lateral wind gust. Simulation results for the F/A-18 aircraft show that the adaptive controller achieves almost perfect tracking whereas the nonadaptive controller cannot achieve a coordinated turn when an aileron failure occurs. The ICE tailless aircraft uses sideslip, washed-out stability axis yaw rate, and stability axis roll rate feedback for both the inner loop eigenstructure assignment controller and the simple adaptive controller. However, the adaptive controller also uses bank angle feedback. Simulation results for the ICE tailless aircraft show that the adaptive controller achieves almost perfect tracking whereas the nonadaptive controller diverges when an all moving tip failure occurs.
Flight Control Design for a Tailless Aircraft Using Eigenstructure Assignment
Clara Nieto-Wire,Kenneth Sobel
International Journal of Aerospace Engineering , 2011, DOI: 10.1155/2011/549131
Abstract: We apply eigenstructure assignment to the design of a flight control system for a wind tunnel model of a tailless aircraft. The aircraft, known as the innovative control effectors (ICEs) aircraft, has unconventional control surfaces plus pitch and yaw thrust vectoring. We linearize the aircraft in straight and level flight at an altitude of 15,000 feet and Mach number 0.4. Then, we separately design flight control systems for the longitudinal and lateral dynamics. We use a control allocation scheme with weights so that the lateral pseudoinputs are yaw and roll moment, and the longitudinal pseudoinput is pitching moment. In contrast to previous eigenstructure assignment designs for the ICE aircraft, we consider the phugoid mode, thrust vectoring, and stability margins. We show how to simultaneously stabilize the phugoid mode, satisfy MIL-F-8785C mode specifications, and satisfy MIL-F-9490D phase and gain margin specifications. We also use a cstar command system that is preferable to earlier pitch-rate command systems. Finally, we present simulation results of the combined longitudinal/lateral flight control system using a full 6DOF nonlinear simulation with approximately 20,000 values for the aerodynamic coefficients. Our simulation includes limiters on actuator deflections, deflection rates, and control system integrators. 1. Introduction We consider the design of a flight control system using eigenstructure assignment for a wind tunnel model of the innovative control effectors (ICEs) aircraft. This tailless aircraft program was first described by Dorsett and Mehl [1] and by Dorsett et al. [2]. The ICE aircraft has many unconventional control surfaces plus pitch and yaw thrust vectoring. Several authors have proposed flight control system designs for the ICE aircraft. Ngo et al. [3] use dynamic inversion with structured singular value synthesis. However, the authors remove the bank angle equation from the model which causes an unstable complex mode to be replaced with an unstable real mode. This occurs because the ICE aircraft does not exhibit the conventional real spiral mode. Sparks [4] uses linear parameter-varying control. Schumacher and Johnson [5] use dynamic inversion with adaptation for self reconfiguring. Shtessel et al. [6] propose reconfigurable sliding mode control with direct adaptation. Hess et al. [7] use sliding mode control with asymptotic observers. However, the results are based only upon linear simulation. The only previous design using eigenstructure assignment was proposed by Jones et al. [8]. The main emphasis of [8] is a method
Dynamics of the Vaginal Ecosystem—Hormonal Influences
Miranda A. Farage, Kenneth W. Miller and Jack D. Sobel
Infectious Diseases: Research and Treatment , 2012, DOI: 10.4137/IDRT.S3903
Abstract: The vagina is a dynamic and finely tuned ecosystem in which homeostasis depends on mutually beneficial interactions between a human female and her resident microorganisms, an ecosystem that can be thrown off balance by a wide variety of both intrinsic and extrinsic factors. Although a functional equilibrium provides stability to the ecosystem considered crucial to maintaining vaginal health, “normal flora” is a concept currently being redefined. New methodologies enable molecular analyses of the vaginal microbiota which have widened the definition of “normal” from a single specific microbiological profile to a range of functional microbial equilibria dependent upon pertinent host and microbial factors. One of the strongest influences on the vaginal microbiota is the hormonal changes that define the reproductive phases of a woman’s life. The vaginal environment is particularly responsive to estrogen, a hormone that creates distinctive changes in the vaginal microbiota. This review summarizes the components of a healthy vaginal ecosystem during the reproductive years, including the characteristics of a healthy equilibrium and factors that can disturb a functional balance. It also summarizes what is known about the vaginal microbiota in childhood and after menopause. Healthful ecosystems at any stage of a female’s reproductive life will be characterized by a microbiota that both maintains physiological function and though changeable, adapts to normal perturbation without succumbing to disease.
Dynamics of the Vaginal Ecosystem—Hormonal Influences
Miranda A. Farage,Kenneth W. Miller,Jack D. Sobel
Infectious Diseases: Research and Treatment , 2010,
Chronic Pain of the Vulva without Dermatologic Manifestations: Distinguishing Among a Spectrum of Clinical Disorders
Miranda A. Farage, Kenneth W. Miller, Paul R. Summers, Jack D. Sobel and William J. Ledger
Clinical Medicine Insights: Women's Health , 2012, DOI: 10.4137/CMWH.S3950
Abstract: The causes of chronic vulvar pain are many and when not accompanied by obvious physical signs they are difficult to unravel. Many common vulvar dermatoses can manifest without obvious erythema or mucocutaneous lesions, as can some less common disorders of both infectious and allergic origin. In addition localized and generalized vulvar dysesthesia, recently defined chronic pain syndromes of neurogenic origin, can also occur in the vulvar area. Chronic vulvovaginal symptoms in early stages are often presumptuously labeled as vulvovaginal candidiasis (VVC) by patients and clinicians alike, which can delay accurate diagnosis. When presented with chronic vulvar pain unaccompanied by verifiable signs, the clinician must effect a sensitive integration of a detailed medical history, including temporal associations of all potential exposures, with more definitive diagnostic tools. Effective use of those available tools can improve initial diagnosis, thus allowing prompt initiation of effective therapy. Optimal therapy will recognize the significant psychological distress that accompanies any chronic pain syndrome.
Chronic Pain of the Vulva without Dermatologic Manifestations: Distinguishing Among a Spectrum of Clinical Disorders
Miranda A. Farage,Kenneth W. Miller,Paul R. Summers,Jack D. Sobel
Clinical Medicine Insights: Women's Health , 2010,
Fast Genome-Wide QTL Analysis Using Mendel
Hua Zhou,Jin Zhou,Tao Hu,Eric M Sobel,Kenneth Lange
Quantitative Biology , 2014,
Abstract: Pedigree GWAS (Option 29) in the current version of the Mendel software is an optimized subroutine for performing large scale genome-wide QTL analysis. This analysis (a) works for random sample data, pedigree data, or a mix of both, (b) is highly efficient in both run time and memory requirement, (c) accommodates both univariate and multivariate traits, (d) works for autosomal and x-linked loci, (e) correctly deals with missing data in traits, covariates, and genotypes, (f) allows for covariate adjustment and constraints among parameters, (g) uses either theoretical or SNP-based empirical kinship matrix for additive polygenic effects, (h) allows extra variance components such as dominant polygenic effects and household effects, (i) detects and reports outlier individuals and pedigrees, and (j) allows for robust estimation via the $t$-distribution. The current paper assesses these capabilities on the genetics analysis workshop 19 (GAW19) sequencing data. We analyzed simulated and real phenotypes for both family and random sample data sets. For instance, when jointly testing the 8 longitudinally measured systolic blood pressure (SBP) and diastolic blood pressure (DBP) traits, it takes Mendel 78 minutes on a standard laptop computer to read, quality check, and analyze a data set with 849 individuals and 8.3 million SNPs. Genome-wide eQTL analysis of 20,643 expression traits on 641 individuals with 8.3 million SNPs takes 30 hours using 20 parallel runs on a cluster. Mendel is freely available at \url{http://www.genetics.ucla.edu/software}.
Intelligence in Williams Syndrome Is Related to STX1A, Which Encodes a Component of the Presynaptic SNARE Complex
Michael C. Gao,Ursula Bellugi,Li Dai,Debra L. Mills,Eric M. Sobel,Kenneth Lange,Julie R. Korenberg
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0010292
Abstract: Although genetics is the most significant known determinant of human intelligence, specific gene contributions remain largely unknown. To accelerate understanding in this area, we have taken a new approach by studying the relationship between quantitative gene expression and intelligence in a cohort of 65 patients with Williams Syndrome (WS), a neurodevelopmental disorder caused by a 1.5 Mb deletion on chromosome 7q11.23. We find that variation in the transcript levels of the brain gene STX1A correlates significantly with intelligence in WS patients measured by principal component analysis (PCA) of standardized WAIS-R subtests, r = 0.40 (Pearson correlation, Bonferroni corrected p-value = 0.007), accounting for 15.6% of the cognitive variation. These results suggest that syntaxin 1A, a neuronal regulator of presynaptic vesicle release, may play a role in WS and be a component of the cellular pathway determining human intelligence.
Fast Genome-Wide QTL Association Mapping on Pedigree and Population Data
Hua Zhou,John Blangero,Thomas D. Dyer,Kei-hang K. Chan,Kenneth Lange,Eric M. Sobel
Quantitative Biology , 2014,
Abstract: Since most analysis software for genome-wide association studies (GWAS) currently exploit only unrelated individuals, there is a need for efficient applications that can handle general pedigree data or mixtures of both population and pedigree data. Even data sets thought to consist of only unrelated individuals may include cryptic relationships that can lead to false positives if not discovered and controlled for. In addition, family designs possess compelling advantages. They are better equipped to detect rare variants, control for population stratification, and facilitate the study of parent-of-origin effects. Pedigrees selected for extreme trait values often segregate a single gene with strong effect. Finally, many pedigrees are available as an important legacy from the era of linkage analysis. Unfortunately, pedigree likelihoods are notoriously hard to compute. In this paper we re-examine the computational bottlenecks and implement ultra-fast pedigree-based GWAS analysis. Kinship coefficients can either be based on explicitly provided pedigrees or automatically estimated from dense markers. Our strategy (a) works for random sample data, pedigree data, or a mix of both; (b) entails no loss of power; (c) allows for any number of covariate adjustments, including correction for population stratification; (d) allows for testing SNPs under additive, dominant, and recessive models; and (e) accommodates both univariate and multivariate quantitative traits. On a typical personal computer (6 CPU cores at 2.67 GHz), analyzing a univariate HDL (high-density lipoprotein) trait from the San Antonio Family Heart Study (935,392 SNPs on 1357 individuals in 124 pedigrees) takes less than 2 minutes and 1.5 GB of memory. Complete multivariate QTL analysis of the three time-points of the longitudinal HDL multivariate trait takes less than 5 minutes and 1.5 GB of memory.
Vaginal Mucormycosis: A Case Report
Jack D. Sobel
Infectious Diseases in Obstetrics and Gynecology , 2001, DOI: 10.1155/s1064744901000205
Abstract: Although Zygomycetes cause life-threatening, opportunistic infections in immunocompromised hosts, the first case of vaginitis caused by Mucor species in a healthy woman is reported. Mucor vaginitis, which caused mild symptoms only, was refractory to conventional azole therapy and resistant to flucytosine. Cure was achieved with topical amphotericin B.
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