1,524 research outputs found
Democracy, Technology and The Civil Rights Project
Democracy has been defined as a political system in which the whole people make, and are entitled to make, the basic determining decisions on important matters of public policy. While the United States is often touted as the world\u27s leading proponent of democracy, many U.S. citizens find themselves unable to engage in one of the central acts of democracy—creating public voice through public engagement. Public engagement in the United States is constrained by our inability to talk through our shared, complementary and divergent values. This lack of public engagement and our inability to speak in a public voice is also driven by a cultural tendency to reduce complex public issues to simple for or against policy positions. The process of building a public voice in the United States is further complicated by the vast racial, ethnic, linguistic and economic diversity, and the imbalance of power that exist among these separate sectors of our society.
The history of this country is replete with the struggles of people to overcome these power imbalances and create opportunities for their voices to become an integral part of the public voice. But, as the 21st century approaches, these same citizens find themselves on the brink of a new battle over citizen participation. This battle is being defined around access to and use of technology. Currently, most Americans are merely bystanders watching the rapid advances in technology shift the political, economic, and social terrain in which their viability as citizens is being determined. For members of the African-American community, and indeed for all communities of color and for economically disadvantaged communities, their ability to participate as equal citizens will now, in part, depend upon their ability to shape the technological world that is redefining the concept of public discourse and public involvement in the political process
Tracking the Martian CO2 Polar Ice Caps in Infrared Images
Researchers at NASA s Jet Propulsion Laboratory have developed a method for automatically tracking the polar caps on Mars as they advance and recede each year (see figure). The seasonal Mars polar caps are composed mainly of CO2 ice and are therefore cold enough to stand out clearly in infrared data collected by the Thermal Emission Imaging System (THEMIS) onboard the Mars Odyssey spacecraft. The Bimodal Image Temperature (BIT) histogram analysis algorithm analyzes raw, uncalibrated data to identify images that contain both "cold" ("polar cap") and "warm" ("not polar cap") pixels. The algorithm dynamically identifies the temperature that separates these two regions. This flexibility is critical, because in the absence of any calibration, the threshold temperature can vary significantly from image to image. Using the identified threshold, the algorithm classifies each pixel in the image as "polar cap" or "not polar cap," then identifies the image row that contains the spatial transition from "polar cap" to "not polar cap." While this method is useful for analyzing data that has already been returned by THEMIS, it has even more significance with respect to data that has not yet been collected. Instead of seeking the polar cap only in specific, targeted images, the simplicity and efficiency of this method makes it feasible for direct, onboard use. That is, THEMIS could continuously monitor its observations for any detections of the polar-cap edge, producing detections over a wide range of spatial and temporal conditions. This effort can greatly contribute to our understanding of long-term climatic change on Mars
Semi-Supervised Data Summarization: Using Spectral Libraries to Improve Hyperspectral Clustering
Hyperspectral imagers produce very large images, with each pixel recorded at hundreds or thousands of different wavelengths. The ability to automatically generate summaries of these data sets enables several important applications, such as quickly browsing through a large image repository or determining the best use of a limited bandwidth link (e.g., determining which images are most critical for full transmission). Clustering algorithms can be used to generate these summaries, but traditional clustering methods make decisions based only on the information contained in the data set. In contrast, we present a new method that additionally leverages existing spectral libraries to identify materials that are likely to be present in the image target area. We find that this approach simultaneously reduces runtime and produces summaries that are more relevant to science goals
Digital twin-based Optimization on the basis of Grey Wolf Method. A Case Study on Motion Control Systems
Nowadays, digital twins are fostering the development of plug, simulate and optimize behavior in industrial cyber-physical systems. This paper presents a digital twin-based optimization of a motion system on the basis of a grey wolf optimization (GWO) method. The digital twin of the whole ultraprecision motion system with friction and backlash including a P-PI cascade controller is used as a basement to minimize the maximum position error. The simulation study and the real-time experiments in trajectory control are performed to compare the performance of the proposed GWO algorithm and the industrial method called Fine tune (FT) method. The simulation study shows that the digital twin-based optimization using GWO outperformed FT method with improvement of 66.4% in the reduction of the maximum position error. The real-time experimental results obtained show also the advantage of GWO method with 18% of improvement in the maximum peak error and 16% in accuracy
Proyecto de una red de estaciones sismológicas, de una red de acelerómetros y de una red de sismoscopios para la República Argentina
Se presenta un proyecto para la instalación de las Redes Nacionales de Estaciones Sismológicas, de Acelerógrafos y de Sismoscopios en la República Argentina en el período 1973-1978.A plan for the installation of the National Network of Seismological Stations, Accelerographs and Seismoscopes in Argentina between 1973-1978 is presented.Asociación Argentina de Geofísicos y Geodesta
Towards Onboard Orbital Tracking of Seasonal Polar Volatiles on Mars
Current conditions on Mars support both a residual polar cap, composed mainly of water ice, and a seasonal cap, composed of CO2, which appears and disappears each winter. Kieffer and Titus characterized the recession of the seasonal south polar cap using an arctangent curve fit based on data from the Thermal Emission Spectrometer on Mars Global Surveyor [1]. They also found significant interannual deviations, at the regional scale, in the recession rate [2]. Further observations will enable the refinement of our models of polar cap evolution in both hemispheres. We have developed the Bimodal Image Temperature (BIT) Histogram Analysis method for the automated detection and tracking of the seasonal polar ice caps on Mars. It is specifically tailored for possible use onboard a spacecraft. We have evaluated BIT on uncalibrated data collected by the Thermal Emission Imaging System (THEMIS) instrument [3] on the Mars Odyssey spacecraft. In this paper, we focus on the northern seasonal cap, but our approach is directly applicable to the future analysis of the southern seasonal ice cap as well
One-Pot Synthesis of Oxidation-Sensitive Supramolecular Gels and Vesicles
Polypeptide-based nanoparticles offer unique advantages from a nanomedicine perspective such as biocompatibility, biodegradability, and stimuli-responsive properties to (patho)physiological conditions. Conventionally, self-assembled polypeptide nanostructures are prepared by first synthesizing their constituent amphiphilic polypeptides followed by postpolymerization self-assembly. Herein, we describe the one-pot synthesis of oxidation-sensitive supramolecular micelles and vesicles. This was achieved by polymerization-induced self-assembly (PISA) of the N-carboxyanhydride (NCA) precursor of methionine using poly(ethylene oxide) as a stabilizing and hydrophilic block in dimethyl sulfoxide (DMSO). By adjusting the hydrophobic block length and concentration, we obtained a range of morphologies from spherical to wormlike micelles, to vesicles. Remarkably, the secondary structure of polypeptides greatly influenced the final morphology of the assemblies. Surprisingly, wormlike micellar morphologies were obtained for a wide range of methionine block lengths and solid contents, with spherical micelles restricted to very short hydrophobic lengths. Wormlike micelles further assembled into oxidation-sensitive, self-standing gels in the reaction pot. Both vesicles and wormlike micelles obtained using this method demonstrated to degrade under controlled oxidant conditions, which would expand their biomedical applications such as in sustained drug release or as cellular scaffolds in tissue engineering
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