Development of an evaluation technique for strapdown guidance systems Interim scientific report

Evaluation technique to measure performance of strapdown guidance systems designed for unmanned interplanetary mission

Development of an evaluation technique for strapdown guidance systems Interim report, 1 Feb. 1968 - 1 Feb. 1969

Evaluation techniques for astrionics systems using aided strapdown inertial guidanc

Comparative analysis of techniques for evaluating the effectiveness of aircraft computing systems

Performability analysis is a technique developed for evaluating the effectiveness of fault-tolerant computing systems in multiphase missions. Performability was evaluated for its accuracy, practical usefulness, and relative cost. The evaluation was performed by applying performability and the fault tree method to a set of sample problems ranging from simple to moderately complex. The problems involved as many as five outcomes, two to five mission phases, permanent faults, and some functional dependencies. Transient faults and software errors were not considered. A different analyst was responsible for each technique. Significantly more time and effort were required to learn performability analysis than the fault tree method. Performability is inherently as accurate as fault tree analysis. For the sample problems, fault trees were more practical and less time consuming to apply, while performability required less ingenuity and was more checkable. Performability offers some advantages for evaluating very complex problems

Study of fault-tolerant software technology

Presented is an overview of the current state of the art of fault-tolerant software and an analysis of quantitative techniques and models developed to assess its impact. It examines research efforts as well as experience gained from commercial application of these techniques. The paper also addresses the computer architecture and design implications on hardware, operating systems and programming languages (including Ada) of using fault-tolerant software in real-time aerospace applications. It concludes that fault-tolerant software has progressed beyond the pure research state. The paper also finds that, although not perfectly matched, newer architectural and language capabilities provide many of the notations and functions needed to effectively and efficiently implement software fault-tolerance

Trends toward States' Rights in the Federalist Party, 1803-1815

This thesis examines the trends towards states' rights and the decline of the Federalist party through the examination of the Louisiana Purchase, the Embargo Act of 1807, and the War of 1812

Character Assessment: Three Essays

I propose a new approach to measuring character skills. In the following three essays, my co-‎authors and I measure the effort that adolescent students appear to put forward on surveys ‎and tests. First, I examine the extent to which students simply skip questions or plead ‎ignorance on surveys. Second, I develop new methods for detecting careless answers, those ‎instances in which students appear to be just filling in the bubbles. I show, using ‎longitudinal datasets, that both measures are predictive of educational degree attainment, ‎independent of measured cognitive ability and other demographic factors. Finally, I ‎demonstrate that international differences in reading, math and science test scores appear in ‎fact to partially reflect international differences in student effort on assessments. Just as some ‎students skip questions and carelessly answer surveys, some students do the same on tests. To ‎the extent that effort on surveys and tests reflects noncognitive skills, presumed international ‎differences in cognitive ability (as measured by standardized tests) might in fact be driven by ‎differences in noncognitive ability. Altogether, the measures explored in the paper present ‎three new methods for quantifying student character skills, which can be used in future ‎research. Throughout, my co-authors and I posit that the character skills that our measures ‎capture are related to conscientiousness and self-control.

Strategic Competitiveness in the 1990s: Challenges and Opportunities for U.S. Executives

U.S. firms face a major global competitiveness challenge. Although the problems relate, in part, to differences in the economic structure, history and cultural differences between the U.S. and foreign rivals, these factors may not explain as much of the variance in competitiveness as they did in the past. Competitiveness problems are also linked to a number of strategic factors under the control of managers. Among them are the absorption of managerial energy in mergers and acquisitions, increasing levels of debt, increasing firm size, greater firm diversification, lack of investment in human capital and inappropriate corporate culture. In response to these problems, many firms are restructuring. When executed properly, restructuring can help managers regain strategic control and improve the competitiveness of their companies. However, restructuring efforts must be accompanied by a renewed emphasis on competitive strengths, improvements in human resource development programs, a refocus on innovation and quality, promotion of an entrepreneurial culture and a global, long-term strategy

Effectiveness evaluation of STOL transport operations

A short-takeoff and landing (STOL) systems simulation model has been developed and implemented in a computer code (known as STOL OPS) which permits evaluation of the operation of a STOL aircraft and its avionics in a commercial airline operating environment. STOL OPS concentrated on the avionics functions of navigation, guidance, control, communication, hazard aviodance, and systems management. External world factors influencing the operation of the STOL aircraft include each airport and its geometry, air traffic at each airport, air traffic control equipment and procedures, weather (including winds and visibility), and the flight path between each airport served by the route. The development of the STOL OPS program provides NASA a set of computer programs which can be used for detailed analysis of a STOL aircraft and its avionics and permit establishment of system requirements as a function of airline mission performance goals

Does the Timing of Money Matter? A Case Study of the Arkansas Academic Challenge Scholarship

This paper examines the effect of a state-financed merit-aid scholarship—the Arkansas Academic Challenge Scholarship (ACS)—on post-secondary outcomes at a large university in Arkansas. Exploiting scholarship eligibility requirements, we implement a fuzzy regression discontinuity design to identify the scholarship’s causal impacts on college outcomes. The analysis focuses on currently enrolled sophomores, juniors, and seniors who receive the scholarship to investigate the broad impacts of receiving money at nontraditional points in an individual’s college trajectory. Findings indicate small, negative impacts of scholarship receipt on short-run outcomes such as GPA and credit accumulation, but large statistically significant declines in the likelihood of graduating within four, five, or six years of matriculation. The youngest cohort, who began receiving funding during their sophomore year of enrollment, primarily drives these findings. However, cohort analysis also reveals that seniors who do not graduate on time are 54 percentage points more likely to graduate within 6 years of matriculation when they receive the scholarship. These results highlight the fact that the timing of receiving money may heavily influence student behavior and postsecondary outcomes

A randomized, phase II study of afatinib versus cetuximab in metastatic or recurrent squamous cell carcinoma of the head and neck.

BackgroundAfatinib is an oral, irreversible ErbB family blocker that has shown activity in epidermal growth factor receptor (EGFR)-mutated lung cancer. We hypothesized that the agent would have greater antitumor activity compared with cetuximab in recurrent or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) patients, whose disease has progressed after platinum-containing therapy.Patients and methodsAn open-label, randomized, phase II trial was conducted in 43 centers; 124 patients were randomized (1 : 1) to either afatinib (50 mg/day) or cetuximab (250 mg/m(2)/week) until disease progression or intolerable adverse events (AEs) (stage I), with optional crossover (stage II). The primary end point was tumor shrinkage before crossover assessed by investigator (IR) and independent central review (ICR).ResultsA total of 121 patients were treated (61 afatinib, 60 cetuximab) and 68 crossed over to stage II (32 and 36 respectively). In stage I, mean tumor shrinkage by IR/ICR was 10.4%/16.6% with afatinib and 5.4%/10.1% with cetuximab (P = 0.46/0.30). Objective response rate was 16.1%/8.1% with afatinib and 6.5%/9.7% with cetuximab (IR/ICR). Comparable disease control rates were observed with afatinib (50%) and cetuximab (56.5%) by IR; similar results were seen by ICR. Most common grade ≥3 drug-related AEs (DRAEs) were rash/acne (18% versus 8.3%), diarrhea (14.8% versus 0%), and stomatitis/mucositis (11.5% versus 0%) with afatinib and cetuximab, respectively. Patients with DRAEs leading to treatment discontinuation were 23% with afatinib and 5% with cetuximab. In stage II, disease control rate (IR/ICR) was 38.9%/33.3% with afatinib and 18.8%/18.8% with cetuximab.ConclusionAfatinib showed antitumor activity comparable to cetuximab in R/M HNSCC in this exploratory phase II trial, although more patients on afatinib discontinued treatment due to AEs. Sequential EGFR/ErbB treatment with afatinib and cetuximab provided sustained clinical benefit in patients after crossover, suggesting a lack of cross-resistance