Development of a Responsive Small Spacecraft

The development of a small spacecraft bus is presented. The approach applied seeks to respond to the requirements of potential users as represented by a large data base of payload missions, while minimizing cost. The development results in a general purpose spacecraft design that is responsive to a wide range of mission requirements, and provides a clear definition of capabilities and interfaces to facilitate user mission design

Financial Markets Analysis by Probabilistic Fuzzy Modelling

For successful trading in financial markets, it is important to develop financial models where one can identify different states of the market for modifying one???s actions. In this paper, we propose to use probabilistic fuzzy systems for this purpose. We concentrate on Takagi???Sugeno (TS) probabilistic fuzzy systems that combine interpretability of fuzzy systems with the statistical properties of probabilistic systems. We start by recapitulating the general architecture of TS probabilistic fuzzy rule-based systems and summarize the corresponding reasoning schemes. We mention how probabilities can be estimated from a given data set and how a probability distribution can be approximated by a fuzzy histogram. We apply our methodology for financial time series analysis and demonstrate how a probabilistic TS fuzzy system can be identified, assuming that a linguistic term set is given. We illustrate the interpretability of such a system by inspecting the rule bases of our models.time series analysis;data-driven design;fuzzy reasoning;fuzzy rule base;probabilistic fuzzy systems

Two Basic Methodological Choices in Wildland Vegetation Inventories: Their Consequences and Implications

In designing inventories of wildland vegetation, two of the many basic methodological choices are: 1) whether data are collected, reduced, and stored in discrete classes or as continuous variables, and 2) whether data are gathered as general purpose variables to bear upon many questions, or as specific purpose variables optimized for only one type of prediction. The effects of these two choices on accuracy of vegetation inventories to predict plant community production were examined by comparing regression models built upon differing sets of independent variables inventoried from a common data base. Contrary to expectations, discrete variables of classified community types were better predictors of plant community production than the same vegetation data reduced as continuous variables by three ordination techniques. Substitution of specific purpose soil and vegetation variables thought to be especially relevant to production did not improve correlations from those of analogous general purpose variables. These results do not show the anticipated accuracy loss of general purpose inventory variables, but such findings cannot yet be generalized to other situations. Implications for the design of practical, extensive survey methods for wildland vegetation are briefly discussed

Aerothermal modeling, phase 1. Volume 1: Model assessment

Phase 1 was conducted as part of the overall NASA Hot Section Technology (HOST) Program. The purpose of this effort was to determine the predictive accuracy of and the deficiencies within the various analytical modules comprising the overall combustor aerothermal model used at General Electric, as well as to formulate recommendations for improvement where needed. This effort involved the assembly of a benchmark quality data base from selected available literature, and from General Electric engine and combustor component test data. This data base was supplemented with additional definitive data obtained from an experimental test program conducted as part of the Phase 1 effort. Using selections from this data base, assessment studies were conducted to evaluate the various modules. Assessment of the internal flow module was conducted using 2-D parabolic and ellipitic, as well as 3-D elliptic internal flow calculations of definitive test data selected from the assembled data base. The 2-D assessment provided methodical examination of the mathematical techniques and the physical submodules, while the 3-D assessment focused on usefulness as a design tool. Calculations of combustor linear metal temperatures, pressure loss performance, and airflow distribution were performed using aerothermal modules which were in general use for many years at General Electric. The results of these assessment provided for the identification of deficiencies within the modules. The deficiencies were addressed in some detail providing a foundation on which to formulate a prioritized list of recommendations for improvement

A Multilevel File System for High Assurance

The designs of applications for multilevel systems cannot merely duplicate those of the untrusted world. When applications are built on a high assurance base they will be constrained by the underlying policy enforcement mechanism_ Consideration must be given to the creation and management of multilevel data structures by untrusted subjects_ Applications should be designed to rely upon the TCB s security policy enforcement services rather than build new access control services beyond the TCB perimeter The results of an analysis of the design of a general purpose le system developed to execute as an untrusted application on a high assurance TCB are presented. The design illustrates a number of solutions to problems resulting from a high assurance environment.Approved for public release; distribution is unlimited

Acoustic environmental accuracy requirements for response determination

A general purpose computer program was developed for the prediction of vehicle interior noise. This program, named VIN, has both modal and statistical energy analysis capabilities for structural/acoustic interaction analysis. The analytic models and their computer implementation were verified through simple test cases with well-defined experimental results. The model was also applied in a space shuttle payload bay launch acoustics prediction study. The computer program processes large and small problems with equal efficiency because all arrays are dynamically sized by program input variables at run time. A data base is built and easily accessed for design studies. The data base significantly reduces the computational costs of such studies by allowing the reuse of the still-valid calculated parameters of previous iterations

The development of a Java image processing framework : a thesis presented in partial fulfillment of the requirements for the degree of Master of Technology in Computer Systems Engineering at Massey University

Practical computer-based teaching methods are often used in conjunction with theory-based lecture sessions and textbooks when teaching image processing. In kind, electronic or on-line image processing courses commonly provide both theoretical and interactive components, however these are often disparate in that the software used to provide each component is independent rather than integrated. It is less common to find electronic instructional resources for image processing that integrate theoretical textual and practical interactive content together into one seamless package. An integrated approach has the advantage that the concepts are more easily conveyed and reinforced when taught 'side-by-side' this way. The World Wide Web offers an attractive medium for delivering an integrated instructional resource on image processing. Applets written in Java may be seamlessly integrated into a hypertext environment. These applets can provide practical demonstrations of image processing concepts along side the relevant hypertext-based theoretical content. One of the major barriers to realising this kind of resource is the development effort required to create the necessary applets. This research demonstrates that the provision of a software framework can significantly reduce the burden of developing these applets. Such a framework provides a common code base that can be drawn upon during applet development, thereby avoiding the need to start from scratch each time a new applet is needed. The framework's design is modelled on a dataflow view of image processing, allowing applets to be built in terms of interconnections between operations. This design is intended to provide the developer with an intuitive and easy-to-use application programming interface (API) for developing applets. The framework also provides APIs for the programmer to implement new operations and data types, thereby extending the capabilities of the framework. Further, the framework's design is general enough to allow it to be used for developing general purpose image processing programs, or other programs that lend themselves to development using a dataflow language. This thesis shows that the proposed framework achieves its aims through an example application of the development of an applet that demonstrates a thresholding operation

The Use of Computer-Assisted Instruction in a Biblical Studies Course: A Case Study

One purpose of this case study was to determine the effect of the introduction of computer-assisted instruction (CAI) materials upon students\u27 learning ability in a college Biblical studies course. Another purpose was to gather information from students with regard to their attitudes toward CAI and its effectiveness in learning the course material. A third purpose of the study was the design of CAI materials using a general application software package. The data base and word processing functions of a general application software package were adapted for CAI in the Biblical studies course. The CAI components employed in the Biblical studies course were a data base function, a word processing exercise, and drill and practice exercises. This case study collected data on 68 students of an introductory Biblical studies course during a college semester. Data on student attitudes were gathered through written questionnaires and interviews. Chi-square was used to investigate the change of student attitudes toward the course. Student learning of the course material was tested using a pretest/posttest design in addition to student grades. An analysis of variance was calculated on the pretest and posttest scores using the years of formal background in religious education as the independent variable to measure gain scores. Student response to the incorporation of CAI into the curriculum of the Biblical studies course showed that 54.7% of the students viewed CAI favorably with higher percentages in relation to each of the CAI activities: 62.7% for the data base, 70.8% for the word processing exercise, and 83% for the drill and practice. Students also perceived the CAI materials as enabling them to learn the material of the course. Students\u27 attitudes with regard to the Biblical studies course were generally favorable and in those cases where negative attitudes were reported at the beginning of the study, 53% of these students reported that they had altered their view at the conclusion of the course. The analysis of variance showed significant gain scores for students with little or no formal background in religious education in relation to students with greater experience in formal religious studies courses (p\u3c.002). The data collected indicated that it was possible to utilize general application software packages in the construction of CAI materials for college level coursework. Implications of this study suggest that positive results in terms of students\u27 perception of learning may be expected from the use of CAI in Biblical studies courses and that other liberal arts subject areas may benefit from the use of CAI. It is recommended that research be conducted for further incorporation of CAI into Biblical studies and religious studies curricula as well as other areas of the liberal arts