Apollo spacecraft systems analysis program. Range coverage for the CSM rendezous radar transponder. Antenna raised 4 in. and tilted forward 15 deg

Range coverage diagrams for CSM rendezvous radar transponder antenna raised 4 in. and tilted forward 15 de

How High Is Too High? Implications of High-Deductible Health Plans

Assesses high deductible health plans, and the likelihood that they would have a substantial effect on either health costs or coverage. Suggests legislative modifications to protect lower wage adults and ensure access to early preventive and primary care

Apollo Spacecraft Systems Analysis Program. Analysis of Rendezvous Radar Pearl Flight Test Data

Flight test data analysis for rendezvous radar performance during simulated lunar missio

Health Care Opinion Leaders' Views on the Future of Long-Term Care

Presents findings from a survey of experts on the challenges for long-term care -- securing adequate financing, developing the required healthcare workforce, and improving the quality of long-term care -- and strategies for addressing them

STUDENT PREFERENCES ABOUT STUDENT-TEACHER COMMUNICATION AND STUDENT PERCEPTIONS OF TEACHER PRESENCE IN AN ONLINE MIDDLE SCHOOL

The purpose of this non-experimental, quantitative survey study was to determine how middle school students in fully online language arts courses perceived their teachers to be present and what methods of communication with the teacher middle school students desired. The purposive sample was composed of 100 sixth and seventh grade language arts students from a large virtual school in the southeastern United States. Student responses were overwhelmingly skewed, and results from the survey indicated a statistically significant finding. Students in online middle school find their teachers to be present and desire to be communicated with using text messages first and phone calls second. The researcher found that communicating with students using the desired mode of communication is beneficial to students in online learning environments and that students find teachers to be present when teachers communicate with students with immediacy. Keywords: virtual school, online education, online learning, online school, virtual education, middle school, teacher presence, teacher immediacy, communication, sixth grade, seventh grade, eighth grade, junior high school, junior high, jr. high, jr. high school, teacher-student communication, student-teacher communicatio

Women at Risk: Why Many Women Are Forgoing Needed Health Care

Based on Commonwealth Fund 2007 Biennial Health Insurance Survey data, compares women's rates of uninsurance or underinsurance, sources of coverage, out-of-pocket and premium expenses, access to care, medical debt, and unmet needs, with those of men

Analog Cancellation of a Known Remote Interference: Hardware Realization and Analysis

The onset of quantum computing threatens commonly used schemes for information secrecy across wireless communication channels, particularly key-based data-level encryption. This calls for secrecy schemes that can provide everlasting secrecy resistant to increased computational power of an adversary. One novel physical layer scheme proposes that an intended receiver capable of performing analog cancellation of a known key-based interference would hold a significant advantage in recovering small underlying messages versus an eavesdropper performing cancellation after analog-to-digital conversion. This advantage holds even in the event that an eavesdropper can recover and use the original key in their digital cancellation. Inspired by this scheme, a flexible software-defined radio receiver design capable of maintaining analog cancellation ratios consistently over 40 dB, reaching up to and over 50 dB, is implemented in this thesis. Maintaining this analog cancellation requires very precise time-frequency synchronization along with accurate modeling and simulation of the channel effects on the interference. The key sources of synchronization error preventing this test bed from achieving and maintaining perfect interference cancellation, sub-sample period timing errors and limited radio frequency stability, are explored for possible improvements. To further prove robustness of the implemented secrecy scheme, the testbed is shown to operate with both phase-shift keying and frequency-modulated waveforms. Differences in the synchronization algorithm used for the two waveforms are highlighted. Interference cancellation performance is measured for increasing interference bandwidth and shown to decrease with such. The implications this testbed has on security approaches based on intentional interference employed to confuse eavesdroppers is approached from the framework proposed in the motivating everlasting secrecy scheme. Using analog cancellation levels from the hardware testbed, it is calculated that secrecy rates up to 2.3 bits/symbol are gained by receivers (intended or not) performing interference cancellation in analog rather than on a digital signal processor. Inspired by the positive gains in secrecy over systems not performing analog cancellation prior to signal reception, a novel secrecy scheme that focuses on the advantage an analog canceller holds in receiver amplifier compression is proposed here. The adversary amplifier is assumed to perform linear cancellation after the interference has passed through their nonlinear amplifier. This is accomplished by deriving the distribution of the interference residual after undergoing an inverse tangent transfer function and perfect linear cancellation. Parameters of this scheme are fit for the radios and cancellation ratios observed in the testbed, resulting in a secrecy gain of 0.95 bits/symbol. The model shows that larger message powers can still be kept secure for the achieved levels of cancellation, thus providing an even greater secrecy gain with increased message transmission power

Culture Change in Nursing Homes: How Far Have We Come?

Presents findings from the Commonwealth Fund 2007 National Survey of Nursing Homes on the extent to which nursing homes have adopted the principles of culture change and are delivering resident-centered care, as well as the benefits the changes have brou