Algorithm for fuel conservative horizontal capture trajectories

A real time algorithm for computing constant altitude fuel-conservative approach trajectories for aircraft is described. The characteristics of the trajectory computed were chosen to approximate the extremal trajectories obtained from the optimal control solution to the problem and showed a fuel difference of only 0.5 to 2 percent for the real time algorithm in favor of the extremals. The trajectories may start at any initial position, heading, and speed and end at any other final position, heading, and speed. They consist of straight lines and a series of circular arcs of varying radius to approximate constant bank-angle decelerating turns. Throttle control is maximum thrust, nominal thrust, or zero thrust. Bank-angle control is either zero or aproximately 30 deg

Flight investigation of a four-dimensional terminal area guidance system for STOL aircraft

A series of flight tests and fast-time simulations were conducted, using the augmentor wing jet STOL research aircraft and the STOLAND 4D-RNAV system to add to the growing data base of 4D-RNAV system performance capabilities. To obtain statistically meaningful data a limited amount of flight data were supplemented by a statistically significant amount of data obtained from fast-time simulation. The results of these tests are reported. Included are comparisons of the 4D-RNAV estimated winds with actual winds encountered in flight, as well as data on along-track navigation and guidance errors, and time-of-arrival errors at the final approach waypoint. In addition, a slight improvement of the STOLAND 4D-RNAV system is proposed and demonstrated, using the fast-time simulation

The 4D area navigation system description and flight test results

A 4D area navigation system was designed to guide aircraft along a prespecified flight path (reference path) such that the aircraft would arrive at the approach gate at a time specified by the ATC controller. Key components to achieve this requirement were: (1) stored reference trajectories; (2) a continuously recomputed capture trajectory to a selected waypoint on the reference trajectory so as to achieve the desired time of arrival; (3) electronic situation displays; and (4) a control system to follow the overall trajectory in space and time. The system was implemented in a digital integrated avionics system (STOLAND) installed on a CV-340 airplane. Although the 4D system was designed primarily for automatic operation, it was flight tested in a flight director mode (the pilot follows the flight director commands), because the CV-340 autopilot servos were not tied to the avionics system. The flight test showed that, even in the flight director mode, the pilot did achieve the objectives of path tracking and time of arrival control with only moderate workload. The system also permitted controlled delay of the time of arrival by path stretching, which takes advantage of the continuously changing capture trajectory to predict the time of arrival. Simulations in the automatic and manual modes were used to complement the flight data

High-Speed Rail Route and Regional Mobility with a Raster-Based Decision Support System: The Texas Urban Triangle Case

This study addresses sustainable transportation in the Texas Urban Triangle at the regional scale. Its aim is to determine the most suitable corridor for new transport infrastructure by employing a spatial decision support system proposed in this project. The system is being tested through its application to a prototype corridor parallel to Interstate 35 between San Antonio and Austin. The basic research questions asked are spatial in nature, so accordingly the geographic information system is the primary method of data analysis. The overall modeling approach is devoted to answering the following questions: What are the considerations to support sustainable growth? What scale or type of infrastructure is necessary? And how to adequately model the transportation corridors to meet the demands and to sustain the living environment at the same time

A flight investigation of a terminal area navigation and guidance concept for STOL aircraft

A digital avionics system referred to as STOLAND has been test-flown in the NASA CV-340 to obtain performance data for time-controlled guidance in the manual flight director mode. The advanced system components installed in the cockpit included an electronic attitude director indicator and an electronic multifunction display. Navigation guidance and control computations were all performed in the digital computer. Approach paths were flown which included a narrow 180-deg turn and a 1-min, 5-deg straight-in approach to the 30-m altitude go-around point. Results are presented for 20 approaches: (1) blended radio/inertial navigation using TACAN and a microwave scanning beam landing guidance system (MODILS) permitted a smooth transition from area navigation (TACAN) to precision terminal navigation (MODILS), (2) guidance system (flight director) performance measured at an altitude of 30.5 m was within that prescribed for category II CTOL operations on a standard runway, and (3) time of arrival at a point about 2 mi from touchdown was about 4 sec plus or minus sec later than the computed nominal arrival time

A flight investigation of a terminal area navigation and guidance concept for STOL aircraft

A digital avionics system was installed in the CV-340 transport aircraft. Flight tests were made to obtain preliminary performance data in the manual flight director mode using time controlled guidance. These tests provide a basis for selection of terminal area guidance, navigation, and control system concepts for short haul aircraft and for investigating operational procedures

Sulfate reduction in surface sediments of the southeast Atlantic continental margin between 15 degrees 38'S and 27 degrees 57'S (Angola and Namibia)

Sulfate reduction rates in the surface sediments from 17 stations from an along-slope transect (1,300 m) and from a cross-slope transect (855-4,766 m) were determined in the continental margin sediments of the Benguela Upwelling system. Profiles at all sites in the upwelling area showed increasing sulfate reduction rates from near zero at the surface to a peak at 2-5 cm (up to 29 nmol cm(-3) d(-1)) and then decreasing exponentially with depth to near background rates at 10-20 cm depth (<2 nmol cm(-3) d(-1)). Depth-integrated sulfate reduction rates were greatest at 1,300 m and decreased exponentially with water depth. Along the transect following the 1,300-m isobath, depth-integrated sulfate reduction rates were highest in the north Cape Basin (1.16 +/- 0.23 mmol m(-2) d(-1)), decreased over the Walvis Ridge (0.67 +/- 0.02 mmol m(-2) d(-1)), and were lowest in the south Angola Basin (0.31 +/- 0.23 mmol m(-2) d(-1)). Depth-integrated sulfate reduction rates were consistent with the known pattern of coastal upwelling intensities and were also strongly correlated with surface organic carbon concentrations. Sulfate reduction rates, both as a function of depth and in comparison with sediment trap data, indicated that lateral downslope transport of organic carbon occurs. Sulfate reduction was estimated to account for 20-90% of the published rates of total oxygen consumption for the sediments at 1,300 m depth and 3-16% of sediments from 2,000 to 3,000 m depth. Comparison of the sulfate reduction rate profiles with the published diffusive oxygen uptake rates showed that the kinetics of oxygen utilization in the surface sediments are much faster than those for anaerobic organic carbon remineralization, although the underlying cause of the difference was not clear

Educational Effects of a Vocabulary Intervention on Preschoolers' Word Knowledge and Conceptual Development: A Cluster‐Randomized Trial

The purpose of this study was to examine the hypothesis that helping preschoolers learn words through categorization may enhance their ability to retain words and their conceptual properties, acting as a bootstrap for self‐learning. We examined this hypothesis by investigating the effects of the World of Words instructional program, a supplemental intervention for children in preschool designed to teach word knowledge and conceptual development through taxonomic categorization and embedded multimedia. Participants in the study included 3‐ and 4‐year‐old children from 28 Head Start classrooms in 12 schools, randomly assigned to treatment and control groups. Children were assessed on word knowledge, expressive language, conceptual knowledge, and categories and properties of concepts in a yearlong intervention. Results indicated that children receiving the WOW treatment consistently outperformed their control counterparts; further, treatment children were able to use categories to identify the meaning of novel words. Gains in word and categorical knowledge were sustained six months later for those children who remained in Head Start. These results suggest that a program targeted to learning words within taxonomic categories may act as a bootstrap for self‐learning and inference generation. كان الغرض من هذه الدراسة هو فحص فرضية أن مساعدة الأطفال في الروضة تعلم كلمات عن طريق التصنيف بإمكانه أن يعزز من قدراتهم على تذكر الكلمات وخصائصها المفاهيمية، بوصفها محفزا للتعلم. قمنا بفحص هذه الفرضية وذلك بالتحقيق في أثر البرنامج التعليمي "عالم المفردات" (WOW) الذي يعتبر تدخلا تكميليا لأطفال الروضة ومصمما من أجل تعليم معرفة الكلمات والتطور المفاهيمي، من خلال النظام التصنيفي ووسائل الإعلام. تضمنت الدراسة مشاركين تتراوح أعمارهم بين 3 و4 سنوات ينتمون إلى 28 روضة أطفال، التي تنتمي إلى 12 مدرسة, خضعت عشوائيا للبحث ومراقبة المجموعات. جرى تقييم الأطفال على معرفة الكلمات واللغة التعبيرية والمعرفة المفاهيمية وأصناف وخصائص المفاهيم في تدخل لمدة سنة كاملة. أظهرت النتائج أن الأطفال الذين خضعوا للبرنامج التعليمي "عالم المفردات" (WOW) قد تفوقوا بصورة مستمرة على نظرائهم الذين خضعوا للمراقبة. علاوة على ذلك, فإن أطفال البحث قد تمكنوا من استخدام الأصناف والتعرف على معنى الكلمات الجديدة. استمر اكتساب الكلمات والمعرفة التصنيفية بعد 6 أشهر بالنسبة للأطفال الذين بقوا في روضة الأطفال. توحي هذه النتائج إلى أنه يمكن لبرنامج يهدف إلى تعلم الكلمات أن يعمل كمحفز للتعلم الذاتي، وتوليد الاستنتاجات. 本研究旨在考查一个假设：帮助学龄前儿童通过分类来学习单词，可提高他们记忆单词及其概念属性的能力，从而发展他们的自主学习能力。作者通过调查「单词世界」(WOW)教学计划的影响来考查这个假设。该教学计划是一个学龄前儿童补充干预计划，旨在透过使用分类学的分类方法及嵌入式多媒体，教授单词知识和发展单词概念。研究参与者是来自12所学校中的28个「启蒙计划」学前儿童班里的3‐4岁儿童，他们被随机分配到干预组和对照组。在一年的干预中，儿童接受单词知识、表达语言、概念知识、类别和概念属性的评估。结果显示，「单词世界」(WOW)干预组的表现一致地优于对照组；此外，干预组儿童可以使用类别来确定新词的词义。仍然留在「启蒙计划」班里的儿童，其单词和类别知识的改进保持稳定至干预后6个月。这些研究结果显示，针对透过分类学的分类方法来学习单词的教学计划，可引导儿童凭自己的力量学习自学和产生推断。 Cette étude avait pour but d'examiner l'hypothíse qu'aider des enfants d'âge préscolaire à apprendre des mots en les catégorisant pourrait favoriser leur capacité à retenir les mots et leurs propriétés, agissant alors comme une amorce d'auto‐apprentissage. Nous avons examiné cette hypothíse en analysant les effets du matériel d'enseignement le Monde des Mots (MDM), un supplément pédagogique destiné aux enfants d'âge préscolaire conçu pour la connaissance des mots et le développement des concepts à l'aide d'une catégorisation taxinomique avec multimédia impliqué. Ont participé à l'étude des enfants de 3 et 4 ans provenant de 28 classes Head Start issus de 12 écoles assignées au hasard au groupe de traitement et au groupe contrôle. Les enfants ont été évalués sur leur connaissance des mots, l'expression orale, les connaissances conceptuelles, les catégories et les propriétés des concepts tout au long de l'année de l'intervention. Les résultats ont montré que les enfants du groupe de traitement MDM ont de maniíre systématique dépassé leur contrepartie du groupe contrôle; en outre, les enfants soumis au traitement ont été en mesure de se servir des catégories pour trouver le sens des mots nouveaux. Les bénéfices dans la connaissance des mots et les connaissances catégorielles sont demeurés six mois plus tard chez les enfants restés dans Head Start. Ces résultats suggírent qu'un programme visant l'apprentissage de mots au sein de catégories taxonomiques peut agir comme une amorce pour l'auto‐apprentissage et la production d'inférences. Проверялась гипотеза о том, что категоризация лексики при обучении дошкольников новым словам может существенно увеличить способность к запоминанию слов и их концептуальных свойств и стимулировать малышей к самообучению. Для расширения их словарного запаса и умения работать с концептами авторы исследовали учебный модуль “Мир слов” (WOW), разработанный в качестве дополнительного вмешательства для дошкольников, которые обучаются по программе Head Start. WOW знакомит детей с таксономической классификацией посредством мультимедийных средств. Трех‐ и четырехлетние дети из 28‐и дошкольных групп в 12‐и школах были случайным образом включены либо в экспериментальную, либо в контрольную группу. На протяжении годичного обучения оценивалось знание слов, выразительность речи, знание концептов, их свойств и категорий, к которым они могут быть причислены. Дети, обучавшиеся по программе WOW, стабильно показывали более высокие результаты, чем их ровесники из контрольных групп. Помимо прочего, эти дети способны использовать категоризацию для определения значений новых слов. Через полгода после окончания обучения эти дети продолжали опережать сверстников по знанию слов и умению категоризировать. Это свидетельствует о том, что программа, предлагающая изучение слов в рамках таксономических категорий, может помочь вырастить поколение, которое будет способно к самообучению и к самостоятельным выводам. La meta de este estudio fue el de investigar la hipótesis que ayudar a los preescolares a aprender palabras por medio de la categorización mejoraría su capacidad de retener palabras y sus propiedades conceptuales, sirviendo de arranque para el auto aprendizaje. Investigamos esta hipótesis estudiando los efectos del programa de enseñanza World of Words (Mundo de palabras; WOW por sus siglas en inglés), una intervención adicional para niños preescolares diseñada para el aprendizaje de palabras y el desarrollo conceptual por medio de la categorización taxonómica y el uso de diversos medios. En este estudio participaron niños de 3 y 4 años de 20 aulas de Head Start en 12 escuelas escogidas al azar en cuanto a grupos de tratamiento y de control. En un año completo de intervención, se evaluaron los estudiantes en cuanto a su conocimiento de palabras, su lenguaje expresivo, su conocimiento conceptual, y las categorías y propiedades de los conceptos. Los resultados mostraron que los niños del grupo de WOW sistemáticamente superaban a los niños del grupo de control; además, los niños del grupo de tratamiento podían usar categorías para encontrar el significado de palabras nuevas. Los adelantos en el conocimiento de palabras y categorías todavía existían 6 meses más tarde para los niños que seguían con Head Start. Estos resultados sugieren que un programa dedicado al aprendizaje de palabras dentro de categorías taxonómicas puede ayudar al autoaprendizaje y la producción de inferencias.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88072/1/RRQ.46.3.3.pd

STOL terminal area operating systems (aircraft and onboard avionics, ATC, navigation aids)

Operational procedures and systems onboard the STOL aircraft which are required to enable the aircraft to perform acceptably in restricted airspace in all types of atmospheric conditions and weather are discussed. Results of simulation and flight investigations to establish operational criteria are presented