5,157 research outputs found
DSN G/T(sub op) and telecommunications system performance
Provided here is an intersystem comparison of present and evolving Deep Space Network (DSN) microwave receiving systems. Comparisons of the receiving systems are based on the widely used G/T sub op figure of merit, which is defined as antenna gain divided by operating system noise temperature. In 10 years, it is expected that the DSN 32 GHz microwave receiving system will improve the G/T sub op performance over the current 8.4 GHz system by 8.3 dB. To compare future telecommunications system end-to-end performance, both the receiving systems' G/T sub op and spacecraft transmit parameters are used. Improving the 32 GHz spacecraft transmitter system is shown to increase the end-to-end telecommunications system performance an additional 3.2 dB, for a net improvement of 11.5 dB. These values are without a planet in the field of view (FOV). A Saturn mission is used for an example calculation to indicate the degradation in performance with a planet in the field of view
Industrialization, the new economy, and the occupational work ethic
The entrepreneurial spirit is alive and well in the new international economy. The information age, the internet, along with e-commerce, e-communication, and e-learning are changing the way businesses and workers interact, communicate and problem solve. The challenges of these multitude of demands on today’s workers has greatly altered our traditional knowledge of the world of work. Vocational educators and trainers worldwide are now faced with a myriad of training challenges. Perhaps the most salient challenge is the understanding and communicating (teaching) of a work ethic suitable for the workplace of this new age
The implications of a University of Louisville first year experience course on student success outcomes based on race and gender.
Extant research has shown that across U.S. institutions, the first and second years of college are the most precarious because of high attrition rates. To address this, many colleges and universities implement First Year Experience (FYE) interventions with hopes of increasing first year GPA, retention rates, and overall college success. Over 90% of colleges and universities either offer or make these FYE interventions mandatory for their first-year/first-time freshmen. There is a large body of research regarding the association of FYE interventions and student outcomes, but the findings are mixed. Extant literature also does little to focus on FYE student outcomes based on race/ethnicity and gender, which is an identified gap and one this study fills. This dissertation is a quantitative examination of a FYE at the University of Louisville, GEN 101. GEN 101 is an example of a First Year Seminar (FYS). FYS courses are a type of FYE. The contextual framework of this dissertation is based on Tinto’s Student Integration Model and concepts of academic and social integration. GEN 101 is required for graduation. All incoming freshmen are encouraged to take it their first semester. Since this course is required and extant literature provides mixed findings about the efficacy of FYE courses, I analyzed associations between GEN 101 completion and first semester GPA along with fall-to-fall retention outcomes. My focus was how African American and Latino students fared in comparison to White students and how women fared in comparison to men. My study results suggested fall GEN 101 completion resulted in higher first semester GPA’s when compared with spring GEN 101 completion. It also suggested female students had a greater chance of being retained into their second year than their male counterparts, all else held constant. African American and Latino students had less of a chance of being retained than White students into their second year, but Latinos were retained at greater rates than African Americans. Taking GEN 101 in the fall was associated with greater outcomes than taking it in the spring and this association intensified when race/ethnicity and gender were considered. Specifically, being an African American male student was associated with greater FYE retention outcomes and being a male in general was associated with greater FYE GPA outcomes
A precision DC-potentiometer microwave insertion-loss test set
Precision dc potentiometer microwave insertion loss test set for calibrating low noise microwave receiving systems used in space communication
Safe2Ditch Steer-To-Clear Development and Flight Testing
This paper describes a series of small unmanned aerial system (sUAS) flights performed at NASA Langley Research Center in April and May of 2019 to test a newly added Steer-to-Clear feature for the Safe2Ditch (S2D) prototype system. S2D is an autonomous crash management system for sUAS. Its function is to detect the onset of an emergency for an autonomous vehicle, and to enable that vehicle in distress to execute safe landings to avoid injuring people on the ground or damaging property. Flight tests were conducted at the City Environment Range for Testing Autonomous Integrated Navigation (CERTAIN) range at NASA Langley. Prior testing of S2D focused on rerouting to an alternate ditch site when an occupant was detected in the primary ditch site. For Steer-to-Clear testing, S2D was limited to a single ditch site option to force engagement of the Steer-to-Clear mode. The implementation of Steer-to-Clear for the flight prototype used a simple method to divide the target ditch site into four quadrants. An RC car was driven in circles in one quadrant to simulate an occupant in that ditch site. A simple implementation of Steer-to- Clear was programmed to land in the opposite quadrant to maximize distance to the occupants quadrant. A successful mission was tallied when this occurred. Out of nineteen flights, thirteen resulted in successful missions. Data logs from the flight vehicle and the RC car indicated that unsuccessful missions were due to geolocation error between the actual location of the RC car and the derived location of it by the Vision Assisted Landing component of S2D on the flight vehicle. Video data indicated that while the Vision Assisted Landing component reliably identified the location of the ditch site occupant in the image frame, the conversion of the occupants location to earth coordinates was sometimes adversely impacted by errors in sensor data needed to perform the transformation. Logged sensor data was analyzed to attempt to identify the primary error sources and their impact on the geolocation accuracy. Three trends were observed in the data evaluation phase. In one trend, errors in geolocation were relatively large at the flight vehicles cruise altitude, but reduced as the vehicle descended. This was the expected behavior and was attributed to sensor errors of the inertial measurement unit (IMU). The second trend showed distinct sinusoidal error for the entire descent that did not always reduce with altitude. The third trend showed high scatter in the data, which did not correlate well with altitude. Possible sources of observed error and compensation techniques are discussed
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The quality of political information
The article conceptualizes the quality of political information and shows how the concept can be used for empirical research. I distinguish three aspects of quality (intelligibility, relevance, validity) and use them to judge the constituent foundations of political information, that is component claims (statements of alleged facts) and connection claims (argumentative statements created by causally linking two component claims). The resulting conceptual map thus entails six manifestations of information quality (component claimintelligibility, connection claim intelligibility, component claimrelevance, connection claim relevance, component claim validity, and connection claim validity). I explain how the conceptual map can be used to make sense of the eclectic variety of existing research, and how it can advance new empirical research, as a guide for determining variation in information quality, as a conceptual template for the analysis of different types of political messages and their common quality deficiencies, and as a generator of new research questions and theoretical expectations
Selective self-categorization: Meaningful categorization and the in-group persuasion effect
Research stemming from self-categorization theory (Turner et al., 1987) has demonstrated that individuals are typically more persuaded by messages from their in-group than by messages from the out-group. The present research investigated the role of issue relevance in moderating these effects. In particular, it was predicted that in-groups would only be more persuasive when the dimension on which group membership was defined was meaningful or relevant to the attitude issue. In two studies, participants were presented with persuasive arguments from either an in-group source or an out-group source, where the basis of the in-group/out-group distinction was either relevant or irrelevant to the attitude issue. Participants' attitudes toward the issue were then measured. The results supported the predictions: Participants were more persuaded by in-group sources than out-group sources when the basis for defining the group was relevant to the attitude issue. However, when the defining characteristic of the group was irrelevant to the attitude issue, participants were equally persuaded by in-group and out-group sources. These results support the hypothesis that the fit between group membership and domain is an important moderator of self-categorization effects
Contact Atomic Structure and Electron Transport Through Molecules
Using benzene sandwiched between two Au leads as a model system, we
investigate from first principles the change in molecular conductance caused by
different atomic structures around the metal-molecule contact. Our motivation
is the variable situations that may arise in break junction experiments; our
approach is a combined density functional theory and Green function technique.
We focus on effects caused by (1) the presence of an additional Au atom at the
contact and (2) possible changes in the molecule-lead separation. The effects
of contact atomic relaxation and two different lead orientations are fully
considered. We find that the presence of an additional Au atom at each of the
two contacts will increase the equilibrium conductance by up to two orders of
magnitude regardless of either the lead orientation or different group-VI
anchoring atoms. This is due to a LUMO-like resonance peak near the Fermi
energy. In the non-equilibrium properties, the resonance peak manifests itself
in a large negative differential conductance. We find that the dependence of
the equilibrium conductance on the molecule-lead separation can be quite
subtle: either very weak or very strong depending on the separation regime.Comment: 8 pages, 6 figure
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