Integrated Inertial/gps

The presence of failures in navigation sensors can cause the determination of an erroneous aircraft state estimate, which includes position, attitude, and their derivatives. Aircraft flight control systems rely on sensor inputs to determine the aircraft state. In the case of integrated Inertial/NAVSTAR Global Positioning System (GPS), sensor failures could occur in the on-board inertial sensors or in the GPS measurements. The synergistic use of both GPS and the Inertial Navigation System (INS) allows for highly reliable fault detection and isolation of sensor failures. Integrated Inertial/GPS is a promising technology for the High Speed Civil Transport (HSCT) and the return and landing of a manned space vehicle

Scheduling revisited workstations in integrated-circuit fabrication

The cost of building new semiconductor wafer fabrication factories has grown rapidly, and a state-of-the-art fab may cost 250 million dollars or more. Obtaining an acceptable return on this investment requires high productivity from the fabrication facilities. This paper describes the Photo Dispatcher system which was developed to make machine-loading recommendations on a set of key fab machines. Dispatching policies that generally perform well in job shops (e.g., Shortest Remaining Processing Time) perform poorly for workstations such as photolithography which are visited several times by the same lot of silicon wafers. The Photo Dispatcher evaluates the history of workloads throughout the fab and identifies bottleneck areas. The scheduler then assigns priorities to lots depending on where they are headed after photolithography. These priorities are designed to avoid starving bottleneck workstations and to give preference to lots that are headed to areas where they can be processed with minimal waiting. Other factors considered by the scheduler to establish priorities are the nearness of a lot to the end of its process flow and the time that the lot has already been waiting in queue. Simulations that model the equipment and products in one of Texas Instrument's wafer fabs show the Photo Dispatcher can produce a 10 percent improvement in the time required to fabricate integrated circuits

Fault detection and isolation for multisensor navigation systems

Increasing attention is being given to the problem of erroneous measurement data for multisensor navigation systems. A recursive estimator can be used in conjunction with a 'snapshot' batch estimator to provide fault detection and isolation (FDI) for these systems. A recursive estimator uses past system states to form a new state estimate and compares it to the calculated state based on a new set of measurements. A 'snapshot' batch estimator uses a set of measurements collected simultaneously and compares solutions based on subsets of measurements. The 'snapshot' approach requires redundant measurements in order to detect and isolate faults. FDI is also referred to as Receiver Autonomous Integrity Monitoring (RAIM)

Well-structured Cooperative Learning in all classrooms: using the Dual Objective to maximize affective and cognitive gain

The authors contend that the research evidence involving Cooperative Learning as a powerful teaching strategy is unprecedented in educational history and is voluminous in breadth. They say that the research supports its use across diverse nations and cultures, across disciplines, with both genders and with all age groups (including higher education). They lament that more educators don’t use it, but they also fear that a greater concern is teachers using badly designed attempts: usually conceptualized as “groupwork”, which fails to meet the specs of the research studies and holds no special promise of success. However, the design and implementation of well-structured Cooperative Learning, as exemplified in their model called The Dual Objective, results in greater conceptual gain, cognitive skill improvement, social skilldevelopment and better self-management by students. This paper explains both Cooperative Learning (CL) as a general category of instructional design and the specific features of the Dual Objective (DO)

Status and Management of the White-tailed Deer in Iowa, 1954-1962

Data regarding populations, hunting, harvest, and biology of Iowa deer (Odocoileus virginianus) gathered by the State Conservation Commission is presented from four ecologically distinct areas. Following 10 consecutive hunting seasons, deer are more abundant and better distributed than before. Abundance through the state is not consistent with available forest habitat. Separate seasons have been permitted for deer of any sex or age by shotgunners and archers on a statewide basis most years. Harvests during recent years have averaged near 20% of an increasing population. Hunting success for gunners during 3-day seasons has been near 45-50%. Bucks outnumber does in the harvest. Fawns comprise 41.7% of the bag. Only 5.8% of the bag has been of deer aged 4½ years or older. Bucks reach maximum weight after 3½ years of age; does at 3½. Weights and antler development reveal significant differences in size and condition exist among deer from four Areas. Weights and antler size average greater for years 1954-62 than in 1953, the first open season. Deer populations in Northeast Iowa are expected to remain stable. Populations in Northern Iowa are believed controlled by hunting more than in other areas because of less protective cover and terrain in northern regions. Southern Iowa is believed to offer the greatest potential for population expansion

Notes on the Biology of the Jackrabbit in Iowa

White-tailed jackrabbits, Lepus townsendii campanius Hollister, are found throughout Iowa with the exception of a few southeastern counties. Over much of their range they are relatively rare. They appear in greatest abundance on the recently glaciated soils in northern and central counties, and on the Missouri loess soils of the west-central counties. Dry growing seasons seem conducive to hare abundance; populations decline during wet seasons. Jackrabbits provide considerable hunting sport during winter. Their pelts are utilized in felt manufacture and their flesh as a staple food for ranch mink. They are known to eat sprouting corn and soybeans, and occasionally damage shrubs and trees. High populations of 114 and 90 jacks per square mile are recorded here. High populations of near 30 jacks per square mile are more common. Average populations over the more favorable portions of their range seem to fall between 5 and 15 per square mile. Average winter weights of 7.5 and 7.9 pounds for males and females respectively are recorded. These contrast with spring weights of 6.8 and 8.3. Sex ratios are essentially even. Breeding activity begins late in February in most years but may be delayed by deep snow and cold temperatures m March. Two and possibly three or four litters per year are produced per female. Litters average 3.6 young rabbits each, and range from one to five. Corpora lutea average 5.75 per pregnancy and range from three to eight. A considerable loss of ova is suggested by the data

LONGITUDINAL ADAPTATIONS IN MUSCLE STRENGTH, FUNCTIONAL PERFORMANCE, GAIT BIOMECHANICS, AND PATIENT-REPORTED FUNCTION AFTER UNILATERAL TOTAL KNEE ARTHROPLASTY

Objective: The aims of this research were to identify gaps in the literature related to impairments after total knee arthroplasty (TKA) (Aim 1) and define recovery between 3 and 6 months after TKA across four domains: 1) hip and knee muscle performance, 2) functional performance, 3) patient-reported function, and 4) biomechanics of walking and stair descent (Aim 2). Additionally, this project sought to explore the relationships between each domain (Aim 3) and establish predictive models to allow clinicians to use clinical measures to predict future gait biomechanics in patients after TKA (Aim 4). Ultimately, the results of this research would quantify post-rehabilitative recovery after TKA and identify potential targets for objective criteria needed for discharge from outpatient rehabilitation. Participants: Thirty-nine individuals completed the study protocol, 21 in the TKA group (7 male, 14 female, height: 1.68 ± 0.08 m, mass: 90.95 ± 21.04 kg, BMI: 32.27 ± 7.4 kg/m2, Age: 60.6 ± 8.1 years) and 18 matched control subjects (7 male, 11 female, height: 1.69 ± 0.10 m, mass: 83.69 ± 20.2 kg, BMI: 29.2 ± 5.5 kg/m2, Age: 61.2 ± 8.8 years). Methods: For Aim 1, a systematic review of the literature related to the four previously stated domains was conducted. In Aims 2-4, a longitudinal design with 3 and 6 months post-surgery assessment time points was used for the TKA group. At both assessment time points, participants underwent maximal voluntary isometric strength testing of bilateral hip abduction, hip external rotation, and knee extension to determine peak strength and rate of torque development (RTD). Participants also performed the five-time sit-to-stand test (FTSTS) and underwent three-dimensional motion analysis while walking at a self-selected speed and during a stair descent task. Patient-reported function was measured using the Knee Injury & Osteoarthritis Outcome Score (KOOS). The control subjects completed the same testing procedures at a single time point. Main Outcome Measures: Outcomes were assessed across four domains. The first domain included peak isometric muscle strength and RTD of hip abduction, hip external rotation, and knee extension. The second and third domains represented functional performance as assessed by the FTSTS and patient-reported function as measured by the KOOS, respectively. The final domain included hip and knee joint kinematics and kinetics during walking and stair descent as measured using three-dimensional motion analysis and inverse dynamics. Statistical Analysis: Aim 1: no formal statistics were utilized in the systematic review. Aim 2 utilized paired sample t-tests for between-limb (operative vs non-operative) and within-limb (3 months vs 6 months post-surgery) comparisons across all four domains. Additionally, independent two-sample t-tests were used to compare the operative and non-operative limbs of the TKA group to the matched control group. In Aim 3, Pearson product-moment correlations were performed to assess the relationships between muscle performance, FTSTS performance, and KOOS scores in the TKA group at 1) 3 months post-surgery, 2) 6 months post-surgery, and 3) between the improvements in these outcomes from 3 to 6 months post-surgery. Lastly, Aim 4 utilized Pearson product-moment correlations and stepwise multiple linear regressions to develop a predictive model using clinical measures assessed at 3 months post-operatively to predict knee flexion excursion during walking at 6 months post-surgery. Results: Aim 1: Improvements in KOOS scores, deficits in peak quadriceps strength, and altered knee joint biomechanics during walking are present during the first 6 months following TKA. Limited evidence exists regarding hip muscle strength deficits, FTSTS performance, and stair descent biomechanics after TKA. Aim 2: Quadriceps and hip external rotation peak strength and RTD, FTSTS performance, gait and stair descent biomechanics, and KOOS scores all demonstrated significant, but modest, improvement between 3 and 6 months post-surgery. However, persistent deficits in quadriceps and hip external rotation peak strength and RTD, FTSTS, movement biomechanics, and KOOS scores compared to control subjects indicate incomplete recovery after TKA both immediately after rehabilitation and following the early post-rehabilitative period. Aim 3: Peak hip muscle strength and FTSTS performance are significantly correlated with KOOS Pain, activities of daily living, and Sport subscales at 3 months post-surgery. Fewer relationships were observed at 6 months post-surgery and between improvements from 3 to 6 months. Aim 4: Quadriceps RTD, hip external rotation RTD, and FTSTS performance were predictive of knee flexion excursion during walking, with quadriceps RTD the strongest of the three predictors. Faster quadriceps RTD, slower hip external rotation RTD, and faster FTSTS performance are predicted to lead to greater knee flexion excursion. Conclusions: Modest improvement in muscle strength and RTD, FTSTS performance, patient-reported function, and biomechanics occur during the post-rehabilitative period after TKA, but all domains remain impaired compared to matched control subjects. Furthermore, muscle strength and RTD and FTSTS performance contribute to greater patient-perceived function and future knee flexion excursion during walking. In order to improve outcomes across domains after TKA, emphasizing improvement in muscle strength, RTD, and FTSTS ability during the first 3 months after surgery is critical as persistent deficits do not resolve by 6 months post-surgery. Lastly, maximizing quadriceps RTD by 3 months post-surgery is likely to lead to improved walking biomechanics at 6 months post-surgery

Anxiety Associated With Increased Risk for Emergency Department Recidivism in Patients With Low-Risk Chest Pain

Anxiety contributes to the chest pain symptom complex in 30% to 40% of patients with low-risk chest pain seen in the emergency department (ED). The validated Hospital Anxiety Depression Scale-Anxiety subscale (HADS-A) has been used as an anxiety screening tool in this population. The objective was to determine the prevalence of abnormal HADS-A scores in a cohort of low-risk chest pain patients and test the association of HADS-A score with subsequent healthcare utilization and symptom recurrence. In a single-center, prospective, observational cohort study of adult ED subjects with low-risk chest pain, the HADS-A was used to stratify participants into 2 groups: low anxiety (score <8) and high anxiety (score ≥8). At 45-day follow-up, chest pain recurrence was assessed by patient report, whereas ED utilization was assessed through chart review. Of the 167 subjects enrolled, 78 (47%) were stratified to high anxiety. The relative risk for high anxiety being associated with at least one 30-day ED return visit was 2.6 (95% confidence interval 1.4 to 4.7) and this relative risk increased to 9.1 (95% confidence interval 2.18 to 38.6) for 2 or more ED return visits. Occasional chest pain recurrence was reported by more subjects in the high anxiety group, 68% vs 47% (p = 0.029). In conclusion, 47% of low-risk chest pain cohort had abnormal levels of anxiety. These patients were more likely to have occasional recurrence of their chest pain and had an increased risk multiple ED return visits