3,037 research outputs found
ASME Mini-Baja RC CAR (Steering and suspension systems)
The issue that this project is concerned with is how to design and build a drivetrain, steering and suspension systems for an RC car. The systems must be simple and functional. Furthermore, these systems will be designed to fit on a small chassis and not interfere with each other. They also need to be strong and durable enough to propel the car forward and maneuver through various obstacles and be built in a way that is easy to take apart and repair quickly. These design problems were approached using basic mechanical design concepts such as gear kinematics, spur and bevel gear design, static and spring analysis as well as linkage design. These concepts were used to analyze the design and ensure it would function properly. Once the designs were finalized the necessary parts and components were machined, printed, and purchased. The result was a functioning RC car with all the necessary systems in place. These systems also fit well with each other on the chassis and they are relatively simple to assemble and dissemble. Overall the vehicle drives with sufficient power (approximately 20 mph), control (turning radius of under 50”) and meets the requirements set out by the principle investigators Mike Cox and Jason Moore
Free-Standing Leaping Experiments with a Power-Autonomous, Elastic-Spined Quadruped
We document initial experiments with Canid, a freestanding, power-autonomous quadrupedal robot equipped with a parallel actuated elastic spine. Research into robotic bounding and galloping platforms holds scientific and engineering interest because it can both probe biological hypotheses regarding bounding and galloping mammals and also provide the engineering community with a new class of agile, efficient and rapidly-locomoting legged robots. We detail the design features of Canid that promote our goals of agile operation in a relatively cheap, conventionally prototyped, commercial off-the-shelf actuated platform. We introduce new measurement methodology aimed at capturing our robot’s “body energy” during real time operation as a means of quantifying its potential for agile behavior. Finally, we present joint motor, inertial and motion capture data taken from Canid’s initial leaps into highly energetic regimes exhibiting large accelerations that illustrate the use of this measure and suggest its future potential as a platform for developing efficient, stable, hence useful bounding gaits.
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Vertical Greening Systems by Integrated Design Approach in Residential Buildings Towards mitigating Urban Heat Island effect the case study of Tehran, Iran
As urbanization grows, the results become more visible. Heat islands are formed due to the loss of green spaces and the consequent disruptive effects of climate change, especially in densely populated urban areas. These phenomena threaten and endanger human health. One solution to compensate for the scarcity of urban green space today is to construct urban green space within the house's walls to provide a suitable and desirable space. Vertical greening systems have recently been recognized and tested by scholars as one of the most effective methods for reducing the harmful impact of heating on the environment. Due to the beauty of this solution, it has also been considered by architectural designers, and today we are witnessing a growing trend of green-covered buildings. In this regard, the number of manufacturing companies is expanding and considering that this solution is in its first steps of growth and there is a need for further study. So, the standard process makes it more functional. This research aims to study the actual process and design of green walls. As a result, at the outset of the journey, the market's current and usable systems should be defined and segmented, followed by analyzing the design and manufacturing process's strengths and limitations. Then, by examining the divisions produced among scientists and companies, the final classification has been presented and analyzed in this study in order to standardize the production process. It should be remembered that businesses from various European, Asian, Australian, and American countries were surveyed to ensure that gaps existed. Based on the current system's flaws, a new Vertical Greening Integrated Approach (VGIS) approach was introduced to make it more popular, economical, and functional. Developing countries like Iran have a significant share in increasing the earth's temperature. However, because of the high price of this nature-based, it is less welcomed and used more as a decorative component in luxury buildings. Therefore, Tehran's study sample, one of the leading centers of pollution and population density and buildings, has been selected. Finally, based on the new approach, the selected green wall simulated on residential building in Tehran. Results show that this strategy's effectiveness was to lower the surface temperature by direct green facade about 10.95 °C and via felt-based living wall 13.95°C
Fabrication feasibility study of a 20 watt per pound solar cell array Final report, 22 Feb. - Dec. 1965
Feasibility of large deployable solar photovoltaic cell array for electric propulsion syste
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An Event System Architecture for Scaling Scale-Resistant Services
Large organizations are deploying ever-increasing numbers of networked compute devices, from utilities installing smart controllers on electricity distribution cables, to the military giving PDAs to soldiers, to corporations putting PCs on the desks of employees. These computers are often far more capable than is needed to accomplish their primary task, whether it be guarding a circuit breaker, displaying a map, or running a word processor. These devices would be far more useful if they had some awareness of the world around them: a controller that resists tripping a switch, knowing that it would set off a cascade failure, a PDA that warns its owner of imminent danger, a PC that exchanges reports of suspicious network activity to its peers to identify stealthy computer crackers. In order to provide these higher-level services, the devices need a model of their environment. The controller needs a model of the distribution grid, the PDA needs a model of the battlespace, and the PC needs a model of the network and of normal network and user behavior. Unfortunately, not only might models such as these require substantial computational resources, but generating and updating them is even more demanding. Modelbuilding algorithms tend to be bad in three ways: requiring large amounts of CPU and memory to run, needing large amounts of data from the outside to stay up to date, and running so slowly that can't keep up with any fast changes in the environment that might occur. We can solve these problems by reducing the scope of the model to the immediate locale of the device, since reducing the size of the model makes the problem of model generation much more tractable. But such models are also much less useful, having no knowledge of the wider system. This thesis proposes a better solution to this problem called Level of Detail, after the computer graphics technique of the same name. Instead of simplifying the representation of distant objects, however, we simplify less-important data. Compute devices in the system receive streams of data that is a mixture of detailed data from devices that directly affect them and data summaries (aggregated data) from less directly influential devices. The degree to which the data is aggregated (i.e., how much it is reduced) is determined by calculating an influence metric between the target device and the remote device. The smart controller thus receives a continuous stream of raw data from the adjacent transformer, but only an occasional small status report summarizing all the equipment in a neighborhood in another part of the city. This thesis describes the data distribution system, the aggregation functions, and the influence metrics that can be used to implement such a system. I also describe my current towards establishing a test environment and validating the concepts, and describe the next steps in the research plan
X-ray satellite
An overview of the second quarter 1985 development of the X-ray satellite project is presented. It is shown that the project is proceeding according to plan and that the projected launch date of September 9, 1987 is on schedule. An overview of the work completed and underway on the systems, subsystems, payload, assembly, ground equipment and interfaces is presented. Problem areas shown include cost increases in the area of focal instrumentation, the star sensor light scattering requirements, and postponements in the data transmission subsystems
Designing energy-efficient computing systems using equalization and machine learning
As technology scaling slows down in the nanometer CMOS regime and mobile computing becomes more ubiquitous, designing energy-efficient hardware for mobile systems is becoming increasingly critical and challenging. Although various approaches like near-threshold computing (NTC), aggressive voltage scaling with shadow latches, etc. have been proposed to get the most out of limited battery life, there is still no “silver bullet” to increasing power-performance demands of the mobile systems. Moreover, given that a mobile system could operate in a variety of environmental conditions, like different temperatures, have varying performance requirements, etc., there is a growing need for designing tunable/reconfigurable systems in order to achieve energy-efficient operation. In this work we propose to address the energy- efficiency problem of mobile systems using two different approaches: circuit tunability and distributed adaptive algorithms.
Inspired by the communication systems, we developed feedback equalization based digital logic that changes the threshold of its gates based on the input pattern. We showed that feedback equalization in static complementary CMOS logic enabled up to 20% reduction in energy dissipation while maintaining the performance metrics. We also achieved 30% reduction in energy dissipation for pass-transistor digital logic (PTL) with equalization while maintaining performance. In addition, we proposed a mechanism that leverages feedback equalization techniques to achieve near optimal operation of static complementary CMOS logic blocks over the entire voltage range from near threshold supply voltage to nominal supply voltage. Using energy-delay product (EDP) as a metric we analyzed the use of the feedback equalizer as part of various sequential computational blocks. Our analysis shows that for near-threshold voltage operation, when equalization was used, we can improve the operating frequency by up to 30%, while the energy increase was less than 15%, with an overall EDP reduction of ≈10%. We also observe an EDP reduction of close to 5% across entire above-threshold voltage range.
On the distributed adaptive algorithm front, we explored energy-efficient hardware implementation of machine learning algorithms. We proposed an adaptive classifier that leverages the wide variability in data complexity to enable energy-efficient data classification operations for mobile systems. Our approach takes advantage of varying classification hardness across data to dynamically allocate resources and improve energy efficiency. On average, our adaptive classifier is ≈100× more energy efficient but has ≈1% higher error rate than a complex radial basis function classifier and is ≈10× less energy efficient but has ≈40% lower error rate than a simple linear classifier across a wide range of classification data sets. We also developed a field of groves (FoG) implementation of random forests (RF) that achieves an accuracy comparable to Convolutional Neural Networks (CNN) and Support Vector Machines (SVM) under tight energy budgets. The FoG architecture takes advantage of the fact that in random forests a small portion of the weak classifiers (decision trees) might be sufficient to achieve high statistical performance. By dividing the random forest into smaller forests (Groves), and conditionally executing the rest of the forest, FoG is able to achieve much higher energy efficiency levels for comparable error rates. We also take advantage of the distributed nature of the FoG to achieve high level of parallelism. Our evaluation shows that at maximum achievable accuracies FoG consumes ≈1.48×, ≈24×, ≈2.5×, and ≈34.7× lower energy per classification compared to conventional RF, SVM-RBF , Multi-Layer Perceptron Network (MLP), and CNN, respectively. FoG is 6.5× less energy efficient than SVM-LR, but achieves 18% higher accuracy on average across all considered datasets
Overview of the PALM model system 6.0
In this paper, we describe the PALM model system 6.0. PALM (formerly an abbreviation for Parallelized Largeeddy Simulation Model and now an independent name) is a Fortran-based code and has been applied for studying a variety of atmospheric and oceanic boundary layers for about 20 years. The model is optimized for use on massively parallel computer architectures. This is a follow-up paper to the PALM 4.0 model description in Maronga et al. (2015). During the last years, PALM has been significantly improved and now offers a variety of new components. In particular, much effort was made to enhance the model with components needed for applications in urban environments, like fully interactive land surface and radiation schemes, chemistry, and an indoor model. This paper serves as an overview paper of the PALM 6.0 model system and we describe its current model core. The individual components for urban applications, case studies, validation runs, and issues with suitable input data are presented and discussed in a series of companion papers in this special issue
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