A time lag study of the vertical motion simulator computer system

A study was performed to evaluate an experimental method to determine time lags in real-time computer systems as the one associated with the Vertical Motion Simulator at Ames Research Center. The approach was to use an ordinary frequency analyzer to measure the phase difference between inputs and outputs of the computer system. The various elements of the program and computational architecture were modeled. Various factors, such as computer frame time and input frequency, were varied so that they were representative of the operational use of the simulator facilities. Experimentally determined results were compared with predictions derived from the simulation models. The results indicate that the frequency analyzer can be readily used to evaluate time lags in systems of this type. Differences between predicted and measured phase values indicate that the hardware and software imparts a time lag of about 5 msec to this facility

Why DO dove: Evidence for register variation in Early Modern English negatives

The development of “supportive” (or “periphrastic”) DO in English suffered a curious and sharp reversal late in the 16th century in negative declaratives and questions according to Ellegård's (1953) database, with a recovery late in the following century. This article examines the variation between DO and the full verb in negative declaratives in this database, from 1500 to 1710. It is shown that both register variation and age-grading are relevant, and that the periods 1500–1575 and 1600–1710 have radically distinct properties. The second period shows substantial age-grading, and is interpreted as having introduced a fresh evaluative principle governing register variation. Negative questions supply data that suggest that the development of clitic negation may have been implicated in the development of the new evaluation. This change in evaluation accounts for the apparent reversal in the development of DO, and we can abandon the view that it was a consequence of grammatical restructuring

Distributed environmental control

We present an architecture of distributed, independent control agents designed to work with the Computer Aided System Engineering and Analysis (CASE/A) simulation tool. CASE/A simulates behavior of Environmental Control and Life Support Systems (ECLSS). We describe a lattice of agents capable of distributed sensing and overcoming certain sensor and effector failures. We address how the architecture can achieve the coordinating functions of a hierarchical command structure while maintaining the robustness and flexibility of independent agents. These agents work between the time steps of the CASE/A simulation tool to arrive at command decisions based on the state variables maintained by CASE/A. Control is evaluated according to both effectiveness (e.g., how well temperature was maintained) and resource utilization (the amount of power and materials used)

Application of technology developed for flight simulation at NASA. Langley Research Center

In order to meet the stringent time-critical requirements for real-time man-in-the-loop flight simulation, computer processing operations including mathematical model computation and data input/output to the simulators must be deterministic and be completed in as short a time as possible. Personnel at NASA's Langley Research Center are currently developing the use of supercomputers for simulation mathematical model computation for real-time simulation. This, coupled with the use of an open systems software architecture, will advance the state-of-the-art in real-time flight simulation

Concept paper on a curriculum initiative for energy, climate change, and sustainability at Boston University

[Summary] Boston University has made important contributions to the interconnected challenges of energy, climate change, and sustainability (ECS) through its research, teaching, and campus operations. This work reveals new opportunities to expand the scope of teaching and research and place the University at the forefront of ECS in higher education. This paper describes the framework for a University-wide curriculum initiative that moves us in that direction and that complements the University’s strategic plan. The central curricular objectives are to provide every undergraduate the opportunity be touched in some way in their educational program by exposure to some aspect of the ECS challenge, and to increase opportunities for every graduate student to achieve a focused competence in ECS. The initiative has six cornerstone initiatives. The first is the Campus as a Living Lab (CALL) program in which students, faculty and staff work together and use our urban campus and its community to study and implement ECS solutions. The second is a university-wide minor degree that helps students develop an integrated perspective of the economic, environmental, and social dimensions of sustainability. The third is one or more graduate certificate programs open to all graduate students. The fourth is an annual summer faculty workshop that develops new ECS curriculum and CALL opportunities. The fifth is web-based resource that underpins the construction of a vibrant knowledge network for the BU community and beyond. Finally, an enhanced sustainability alumni network will augment professional opportunities and generate other benefits. The learning outcomes of this initiative will be realized through the collaborative work of faculty, students, and staff from all 17 colleges and schools. The initiative will leverage existing BU student resources such as the Thurman Center, Build Lab, and Innovate@BU. Benefits of this initiative, beyond the curriculum, include acceleration towards the goals of our Climate Action Plan; improving the “sustainability brand” of BU; enhancing the ability to attract students and new faculty; strengthening our alumni and campus communities; deepening our ties with the city of Boston; and the potential to spin off new social and technological innovations.Published versio