A human factors approach to range scheduling for satellite control

Range scheduling for satellite control presents a classical problem: supervisory control of a large-scale dynamic system, with unwieldy amounts of interrelated data used as inputs to the decision process. Increased automation of the task, with the appropriate human-computer interface, is highly desirable. The development and user evaluation of a semi-automated network range scheduling system is described. The system incorporates a synergistic human-computer interface consisting of a large screen color display, voice input/output, a 'sonic pen' pointing device, a touchscreen color CRT, and a standard keyboard. From a human factors standpoint, this development represents the first major improvement in almost 30 years to the satellite control network scheduling task

Improving Agriculture Students' Understanding of Global Production Systems through Distance Learning

Globalization is a fundamental force currently shaping agricultural sector throughout the world. To make sound decisions in a globalised economy, agricultural producers and agribusiness managers must have a high level of understanding of the international dimensions of their industry. To address this need, we are developing a course aimed at helping agricultural students better understand the managerial environment faced by producers worldwide. This course will provide students an opportunity to learn about agricultural production, and the context in which it occurs, by analyzing real-world farm case studies in various countries on four continents in both hemispheres of the globe. Eight case studies are being developed to exemplify the production and managerial environment in five different countries (Russia, Australia, Uruguay, Brazil, and the U.S.). Each case study will include a written description of the case, as well as a video tour of the farm and surrounding region and an interview with the farm manager. The case studies will provide the principal building blocks for the comparative farm management systems course to be taught at each of the four cooperating universities. Through the comparative farm management systems course, students will: (1) obtain a better understanding of the production agriculture sectors of the world, (2) discuss regional agricultural economic issues with instructors who are experts from each country, and (3) gain real-world problems solving experience in international settings through case study analysis. The case studies and course curriculum will be made available to other universities through a project web page and distribution of case study CD-ROMs.globalization, international, comparative farm case studies, distance learning, Teaching/Communication/Extension/Profession,

Paper Session II-C - Astro: A Computer-Aided Scheduling Tool for Operational Satellite Control

Range scheduling for satellite control presents a classical problem of a data intensive task with a very small allowance for human error. On any given day, interrelated information depicting 600-1000 entries of satellite visibilities and scheduled range support must be interpreted and used to make decisions that can be critical to the survival of valuable orbital assets. Given an environment which must account for unexpected equipment outages and satellite anomalies, the scheduling task can exceed acceptable workload levels. Thus, range scheduling for satellite control can benefit greatly from computer assistance and a human factors approach to the task. This paper describes the development, user evaluation, and operational activation of a semi-automated network range scheduling system incorporating a synergistic humancomputer interface consisting of a large screen color display, voice input/output, a sonic penn pointing device, a touchscreen color CRT, and a standard keyboard. The development and operational use of ASTRO represent the first major improvement in almost 30 years to the range scheduling task

Aliphatic polyester polymer stars: synthesis, properties and applications in biomedicine and nanotechnology

abstract: A critical review: the ring-opening polymerization of cyclic esters provides access to an array of biodegradable, bioassimilable and renewable polymeric materials. Building these aliphatic polyester polymers into larger macromolecular frameworks provides further control over polymer characteristics and opens up unique applications. Polymer stars, where multiple arms radiate from a single core molecule, have found particular utility in the areas of drug delivery and nanotechnology. A challenge in this field is in understanding the impact of altering synthetic variables on polymer properties. We review the synthesis and characterization of aliphatic polyester polymer stars, focusing on polymers originating from lactide, epsilon-caprolactone, glycolide, beta-butyrolactone and trimethylene carbonate monomers and their copolymers including coverage of polyester miktoarm star copolymers. These macromolecular materials are further categorized by core molecules, catalysts employed, self-assembly and degradation properties and the resulting fields of application (262 references)

Tacticity Control in the Synthesis of Poly(lactic acid) Polymer Stars with Dipentaerythritol Cores

The synthesis of a family of polymer stars with arms of varied tacticities is discussed. The effect of polymer tacticity on the physical properties of these polymer stars is presented. Dipentaerythritol cores support six poly(lactic acid) (PLA) arms. Lewis acidic tin and aluminum catalysts control the polymerization to afford polymer stars of variable tacticity. The analysis of these polymers by NMR spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and differential scanning calorimetry reveals the effects of tacticity control on the physical properties of the polymer stars. Preliminary decomposition studies suggest that the biodegradation profile of a polymer star may also be tuned by stereochemical control. This is the first systematic altering of tacticity in PLA polymer stars, showing that polymer tacticity can have a great impact on star properties.PT: J; UT: BIOSIS:PREV20110005905

Developing a research framework for understanding the social realities, with special reference to Sri Lankan entrepreneurs

This paper identifies and examines issues of relevance for increasing effectiveness of entrepreneurial management research. These issues emerged from research into entrepreneurial behaviour and underlying motivations in Sri Lanka. Understanding of socially- and culturally-bound social actors, social actions and social outputs in entrepreneurial activity requires context-sensitivity, expressed through cognisance of institutional characteristics, the interface between cultural values and business, and historical and cultural forces which impact on entrepreneurship. We suggest that this requires exploration through bottom-up translations of actions consistent with the beliefs and values of the actors involved, employing qualitative methodology to ground the reality of human behaviour in deep-rooted cultural and social contexts. Thorough interpretation of holistic case studies that are capable of capturing the actors' viewpoints brings appropriate insights to the field of entrepreneurship

What Will it Take to Make Solar Panels Cool?

With the predicted results of climate change looming, humanity must do all it can to limit greenhouse gas emissions. Maintaining a habitable environment along with the high quality of living associated with developed nations requires investment in renewable energy. Because national governments often fail to make responsible decisions for their country\u27s future, this burden falls to institutions like UMass Amherst. Although costly investments like solar panels substantially improve the sustainability of campus, some innovative improvements of existing solar energy infrastructure can go a long way. For example, when solar panels heat up they lose photovoltaic efficiency. We propose that UMass institute cooling systems on current and future solar panel structures. This may sound extravagant, but in this paper we outline a plan for a simple and affordable cooling system that can be constructed from supplies bought at a local hardware store. The University spent approximately $1.5 million dollars on the new solar canopy atop the Robsham’s Visitor Center. This structure generates an estimated$40,000 worth of electricity each year, with a 38 year return on investment. We expect a cooling system for each canopy to cost around $500 and to improve power output by more than 10 percent. This means that by the most conservative estimate, a$500 investment will generate an additional $4,000 worth of electricity, reducing the return on investment time by 4 years. Compared with the initial solar canopy investment, this magnitude of electricity generation would have cost$150,000. By comparison, $500 is peanuts. Read on to see how a little ingenuity can go a long way to save money and the environment

Angular Momentum Evolution of Stars in the Orion Nebula Cluster

(Abridged) We present theoretical models of stellar angular momentum evolution from the Orion Nebula Cluster (ONC) to the Pleiades and the Hyades. We demonstrate that observations of the Pleiades and Hyades place tight constraints on the angular momentum loss rate from stellar winds. The observed periods, masses and ages of ONC stars in the range 0.2--0.5 M$_\odot$, and the loss properties inferred from the Pleiades and Hyades stars, are then used to test the initial conditions for stellar evolution models. We use these models to estimate the distribution of rotational velocities for the ONC stars at the age of the Pleiades (120 Myr). The modeled ONC and observed Pleiades distributions of rotation rates are not consistent if only stellar winds are included. In order to reconcile the observed loss of angu lar momentum between these two clusters, an extrinsic loss mechanism such as protostar-accretion disk interaction is required. Our model, which evolves the ONC stars with a mass dependent saturation threshold normalized such that $\omega_{crit} = 5.4 \omega_\odot$ at 0.5 \m, and which includes a distribution of disk lifetimes that is uniform over the range 0--6 Myr, is consistent with the Pleiades. This model for disk-locking lifetimes is also consistent with inferred disk lifetimes from the percentage of stars with infrared excesses observed in young clusters. Different models, using a variety of initial period distributions and different maximum disk lifetimes, are also compared to the Pleiades. For disk-locking models that use a uniform distribution of disk lifetimes over the range 0 to $\tau_{max}$, the acceptable range of the maximum lifetime is $3.5 < \tau_{max} < 8.5$ Myr.Comment: 21 pages, 7 figures, submitted to Ap