Development of a flight software testing methodology

The research to develop a testing methodology for flight software is described. An experiment was conducted in using assertions to dynamically test digital flight control software. The experiment showed that 87% of typical errors introduced into the program would be detected by assertions. Detailed analysis of the test data showed that the number of assertions needed to detect those errors could be reduced to a minimal set. The analysis also revealed that the most effective assertions tested program parameters that provided greater indirect (collateral) testing of other parameters. In addition, a prototype watchdog task system was built to evaluate the effectiveness of executing assertions in parallel by using the multitasking features of Ada

A methodology for testing fault-tolerant software

A methodology for testing fault tolerant software is presented. There are problems associated with testing fault tolerant software because many errors are masked or corrected by voters, limiter, or automatic channel synchronization. This methodology illustrates how the same strategies used for testing fault tolerant hardware can be applied to testing fault tolerant software. For example, one strategy used in testing fault tolerant hardware is to disable the redundancy during testing. A similar testing strategy is proposed for software, namely, to move the major emphasis on testing earlier in the development cycle (before the redundancy is in place) thus reducing the possibility that undetected errors will be masked when limiters and voters are added

Executable assertions and flight software

Executable assertions are used to test flight control software. The techniques used for testing flight software; however, are different from the techniques used to test other kinds of software. This is because of the redundant nature of flight software. An experimental setup for testing flight software using executable assertions is described. Techniques for writing and using executable assertions to test flight software are presented. The error detection capability of assertions is studied and many examples of assertions are given. The issues of placement and complexity of assertions and the language features to support efficient use of assertions are discussed

Employment Discrimination-Seniority Systems Under Title VII: American Tobacco Co. v. Pattersonand Pullman-Standard v. Swint

Title VII of the Civil Rights Act of 1964 is a broad remedial measure designed \u27to assure equality of employment opportunities.\u27 The Su- preme Court, in the seminal Title VII employment discrimination case, Griggs v. Duke Power Co.,s stated that [t]he objective of Congress in the enactment of Title VII ...was to achieve equality of employment oppor- tunities and remove barriers that have operated in the past to favor an identifiable group of white employees over other employees. The Griggs decision has provided the basic framework for analyzing employment dis- crimination cases. The Court held that any employment practices, proce- dures or tests (employment practices) that had the consequences of favoring white employees over other employees was proscribed by Title VII.5 The Griggs Court perceived that Congress\u27 intent was to remove all barriers to employment which operate to discriminate against blacks and all other protected classes.6 Discriminatory intent was not necessary.7 Any act of an employer that operated to freeze the status quo of prior dis- criminatory employment practices was deemed illegal unless excused by business necessity. 0 Congress\u27 clear intent in including Title VII in the Civil Rights Act of 1964 was to remove barriers to employment for minor- ities and to force employers to make employment decisions on the basis of job qualifications rather than on the basis of race, sex, religion or na- tional origin. Congress included sanctions in Title VII against an em- ployer whose employment practices discriminate against a qualified job applicant or employee. Section 706(g) 2 empowers the courts to enjoin the employer from engaging in such unlawful employment practice, and order such affirmative action as may be appropriate, which may include... reinstatement or hiring of employees, with or without back pay ... or any other equitable relief as the court deems appropriate

Examining the Efficacy of a 1-Session Brief Behavioral Activation Intervention with University Students with Mild to Moderate Depressive Symptoms

Early intervention may increase the likelihood that students with depressive symptoms complete degree requirements and reduce the likelihood of negative outcomes associated with depression in adults. The goal of this study was to assess the efficacy of a 1-session version of Brief Behavioral Activation Treatment for Depression-Revised (BATD-R; Lejuez, Hopko, Acierno, Daughters, & Pagoto, 2011) with university students with mild-to-moderate depressive symptoms. Participants (N = 39) were randomly assigned to either a clinical or a control group. Participants completed measures of depression, negativity bias, mindfulness, and experiential avoidance at pre-intervention, two-week follow-up, and one-month follow-up. Both ITT and study completer analyses were conducted. There was a significant main effect of session, such that depression scores decreased from Session 1 to Session 2 and increased from Session 2 to Session 3. Depression scores at Session 3 were significantly lower than scores at Session 1. No significant differences were identified for condition at any time, suggesting that factors other than the intervention were causing the changes in depression scores. Implications for theory and practice are discussed

Dynamic assertion testing of flight control software

Digital Flight Control System (DFCS) software was used as a test case for assertion testing. The assertions were written and embedded in the code, then errors were inserted (seeded) one at a time and the code executed. Results indicate that assertion testing is an effective and efficient method of detecting errors in flight software. Most errors are eliminate at an earlier stage in the development than before

Dynamic assertion testing of flight control software

An experiment in using assertions to dynamically test fault tolerant flight software is described. The experiment showed that 87% of typical errors introduced into the program would be detected by assertions. Detailed analysis of the test data showed that the number of assertions needed to detect those errors could be reduced to a minimal set. The analysis also revealed that the most effective assertions tested program parameters that provided greater indirect (collateral) testing of other parameters

The Watchdog Task: Concurrent error detection using assertions

The Watchdog Task, a software abstraction of the Watchdog-processor, is shown to be a powerful error detection tool with a great deal of flexibility and the advantages of watchdog techniques. A Watchdog Task system in Ada is presented; issues of recovery, latency, efficiency (communication) and preprocessing are discussed. Different applications, one of which is error detection on a single processor, are examined

Patron Demand Deposit Account and Regional Patronage Financing Activities of Agribusiness Cooperatives

This paper investigates agribusiness cooperatives' reliance on patron demand deposit accounts (PDDAs) and regional patronage as sources of capital. Approximately 13% of cooperatives carry PDDAs, typically fruit cooperatives, of which over one-half have no financial protection against large unexpected withdrawals. Cooperatives with PDDAs must be concerned with potential legal conflicts regarding the handling of these accounts, as evidenced by a U.S. Supreme Court case classifying PDDAs as securities. Supply cooperatives are most likely to show investment in other cooperatives as a high percentage of total assets, which could generate insolvency issues for locals.cooperative finance, patron demand deposit accounts, regional patronage., Agricultural Finance, Agribusiness,

Exploring the Drugs-Homicide Connection

Although research generally assumes a close relationship between drugs and violence, very little is known about the many different roles drugs can play in criminal events. Drug related as an event classification scheme is relatively common in homicide research, as well as other areas of inquiry, and is usually understood to be an important component in the causal processes of criminal events. Yet such classification schemes often suggest a simple, unidimensional construct. In reality, drug-related crimes are com-plex events. The purpose of this researchwas first to disaggregate the concept of drug-related homicide by providing an event classification scheme that conceptualizes the diverse roles drugs play in drug-related events.Acategorical coding scheme is presented that is similar to that proposed by Goldstein (1995) and later tested by Brownstein and colleagues (Brownstein & Goldstein, 1990; Brownstein, Baxi, Goldstein, & Ryan, 1992) that specifies three distinct types of homicide events. Included among these are (a) events that involved no evidence of illicit drugs associated with the homicide event, (b) those that involved the presence of drugs or drug use at the scene as well as events where either the victim and/or offender were buying or selling drugs (we term this peripherally drug-related homicides), and (c) events where the sale or use of drugswas the motivating feature of the homicide event. In some situations, there may be overlap between categories b and c; however, category c is distinct in that it includes features of motivation. The second purpose was to determine the relative importance of various situational and contextual characteristics of homicide events in understanding different types of drug-related events. Delineating these features will be an important step in filling in the gaps of knowledge about the assumed relationship between drugs and violence