Исследование чувствительности целевого функционала к вариациям проектных параметров ракеты-носителя

Сформулирована задача исследования параметрической чувствительности целевого функционала, характеризующего качество проектирования ракеты-носителя (РН), к отклонениям проектных параметров от номинальных значений. Оценено влияние вариаций проектных параметров на целевой функционал, определены диапазоны, в которых вариации исследуемых параметров не оказывают существенного влияния на эффективность выполнения целевой задачи. Классификация проектных параметров по степени их влияния на целевой функционал может быть использована при разработке эффективных методов оптимизации для решения задач начального этапа проектирования РН.Сформульовано завдання дослідження параметричної чутливості цільового функціонала, який характеризує якість проектування ракети-носія (РН), щодо відхилень проектних параметрів від номінальних значень. Оцінено вплив варіацій проектних параметрів на цільовий функціонал, визначені діапазони, у яких варіації параметрів, що досліджуються, роблять істотний вплив на ефективність виконання цільового завдання. Класифікація проектних параметрів в залежності від їхнього впливу на цільовий функціонал може бути використана при розробці ефективних методів оптимізації для рішення завдань початкового етапу проектування РН.The problem of studies on a parametric sensitivity of the criterion functional characterizing the design quality of the launch vehicle (LV) to project parameters deviation from nominal values is formulated. The influence of design parameters variations on the criterion functional is evaluated. Ranges in which variations in parameters under consideration do not exert considerable influence on the efficiency of the desired problem realization are determined. Classification of design parameters according to their influence on the criterion functional can be used to develop efficient methods of optimization for solution of problems of an initial phase of the LV design

Strategic monitoring of crop yields and rangeland conditions in Southern Africa with Remote Sensing

The monitoring of vegetation resources is of vital importance for Southern African countries because of the dominance of agriculture in the economy. The use of remote sensing techniques in a national or local planning context is particularly adapted to the Southern African conditions because large areas can be covered regularly with minimal requirements for field based infrastructure. Furthermore, relatively low-cost receiving stations have been installed in the meteorological departments and other local institutions, which makes satellite data available in realtime. Real-time acquisition is essential for the operational monitoring of vegetation development and remote sensing plays a significant role in three main areas: • Inventory or mapping of cover types • Monitoring of vegetation conditions relative to the norm • Estimates of biomass In this research operational techniques were developed in each of these areas with the participation and involvement of users. Remote sensing and field survey techniques for inventory and mapping of cover types were adapted and developed from existing experience in the European context to match the requirements in Southern Africa. The need for an unbiased sample of field observations, for the calibration of digital classification of satellite imagery was identified and methodology for its collection demonstrated. Methods developed for the inventory of crop types in Europe were successfully adapted to the African rangeland. The levels of classification accuracy achieved were similar to that obtained in the European context for a classification scheme of equivalent complexity. A Vegetation Productivity Indicator (VPI) was developed for monitoring vegetation conditions based on real-time acquisition of NOAA HRPT imagery from a local receiving station and a historical Normalised Difference Vegetation Index (NDVI) archive. The VPI maps show departure from normal vegetation response using methodology similar to the analysis of extreme events in hydrology, in near real-time. The method was successfully implemented in Zambia to monitor maize production and in Namibia to monitor rangeland. The VPI was significantly correlated with rainfall. The technique was successfully transferred to the Department of Meteorological Services in Botswana where VPI maps are produced routinely and presented to the inter-ministerial drought committee for assessing rangeland conditions. Methodology for rapid biomass assessment was developed using simple physiognomic plant parameters. Field Measurements were taken in four different cover types (grassland, steppe and shrub and tree savanna) and correlated with the NDVI derived from the satellite observations in Etosha National Park, Namibia in near real-time. The pooled regression relationship which was obtained was highly statistically significant. However, the regression model excluding the two savanna types exhibited a higher correlation suggesting that there might be a separate relationship between savanna biomass and NDVI. Biomass maps were produced using the pooled relationship and their potential for operational targeting of areas suitable for prescribed burning was illustrated. Although the methods and techniques in this work were developed using time series of NOAA-AVHRR and the NDVI, they can all be adapted to include data from new sensors systems and other vegetation indices as they become available. Methods demonstrated in this work can be integrated to form a suitable framework for a national vegetation resources monitoring system. This would assist Southern African governments in making decisions related to vegetation resources by providing sound and timely technical advice.Ph

Évolution de l'identité d'apprenant et des préférences d'apprentissage d'élèves de secondaire s'engageant dans un cursus théâtral scolaire : une étude de cas multiples

Notre recherche s’intéresse à l’évolution de l’identité d’apprenant et des préférences d’apprentissage d’élèves de secondaire 5 s’engageant, pour la première fois, dans un cursus théâtral dans leur scolarité. Nous cherchons à identifier quelles sont les caractéristiques de l’évolution de leur identité d’apprenant en théâtre, soit la façon dont ils et elles se définissent dans le contexte théâtral, et celles de l’évolution de leurs préférences d’apprentissage en théâtre, soit la façon préférentielle qu’ils et elles ont d’apprendre, et qui incluent, comme définies par Vermunt (1996; 1998), des composantes cognitives mais également des composantes conatives. Également, nous cherchons à identifier les caractéristiques de l’évolution de l’identité d’apprenant et des préférences d’apprentissage globales, soit dans la scolarité en général des élèves. Enfin, nous cherchons à déterminer si certaines caractéristiques sont communes à ces évolutions. Pour ce faire, nous avons rencontré six élèves de secondaire 5 débutant l’activité théâtrale et avons réalisé une étude de cas multiples comprenant plusieurs collectes de données : une entrevue semi-dirigée avec chaque élève au début de l’année, au moment de l’introduction de la discipline théâtrale; une nouvelle entrevue semi-dirigée à la fin de l’année, avec chaque élève et comprenant un volet d’auto confrontation; une entrevue avec leur enseignante de théâtre; et une observation non participative au sein d’un cours. Nous avons ensuite effectué une analyse du corpus pour identifier les dimensions évoluant chez chaque élève, avant de réaliser l’étude de cas multiple. Notre recherche montre que certaines caractéristiques du contexte théâtral influencent fortement la formation de l’identité d’apprenant et l’évolution des préférences d’apprentissage, et nous avons pu identifier certaines évolutions se transférant dans le contexte global pour plusieurs élèves – notamment la confiance en soi, l’application de la matière pour l’apprendre ou le développement de l’autonomie.Our research aims to understand the evolution of students’ learning identity and learning preferences when they engage, for the first time, in a theatrical curriculum. We seek to identify the characteristics of the evolution oft heir learning identity in drama, that is, how they define themselves in the theatrical context. Also, we seek to identify those of the evolution of their learning preferences in drama, or the preferential way they learn, which include, as defined by Vermunt (1996; 1998), cognitive components as well as conative components. We also seek to identify the characteristics of the evolution of global learning identity and global learning preferences, i.e. in the students’ general context of learning. Finally, we seek to determine whether certain characteristics are common to these developments. To do so, we met six secondary students starting drama and carried out a multiple case study including several data collections: a semi-structured interview with each student at the beginning of the year, just after the introduction of drama in their curriculum; a new semi-structured interview at the end of the year, with each student and including a self-confrontation component; an interview with their drama teacher; and non-participatory observation within a course. We then performed a corpus analysis to identify the dimensions evolving in each student, before carrying out the multiple case study. Our research shows that certain characteristics of the theatrical context strongly influence the formation of the learning identity and the evolution of learning preferences, and we have been able to identify certain evolutions that are transferred in the global context for several students – notably self-confidence, the application of the material to learn it or the development of autonomy