Optimization of an optically implemented on-board FDMA demultiplexer

Performance of a 30 GHz frequency division multiple access (FDMA) uplink to a processing satellite is modelled for the case where the onboard demultiplexer is implemented optically. Included in the performance model are the effects of adjacent channel interference, intersymbol interference, and spurious signals associated with the optical implementation. Demultiplexer parameters are optimized to provide the minimum bit error probability at a given bandwidth efficiency when filtered QPSK modulation is employed

On Systematic Design of Protectors for Employing OTS Items

Off-the-shelf (OTS) components are increasingly used in application areas with stringent dependability requirements. Component wrapping is a well known structuring technique used in many areas. We propose a general approach to developing protective wrappers that assist in integrating OTS items with a focus on the overall system dependability. The wrappers are viewed as redundant software used to detect errors or suspicious activity and to execute appropriate recovery when possible; wrapper development is considered as a part of system integration activities. Wrappers are to be rigorously specified and executed at run time as a means of protecting OTS items against faults in the rest of the system, and the system against the OTS item's faults. Possible symptoms of erroneous behaviour to be detected by a protective wrapper and possible actions to be undertaken in response are listed and discussed. The information required for wrapper development is provided by traceability analysis. Possible approaches to implementing “protectors” in the standard current component technologies are briefly outline

Protective wrapping of off-the-shelf components

System designers using off-the-shelf components (OTSCs), whose internals they cannot change, often use add-on “wrappers” to adapt the OTSCs’ behaviour as required. In most cases, wrappers are used to change “functional” properties of the components they wrap. In this paper we discuss instead protective wrapping, the use of wrappers to improve the dependability – i.e., “non-functional” properties like availability, reliability, security, and/or safety – of a component and thus of a system. Wrappers can improve dependability by adding fault tolerance, e.g. graceful degradation, or error recovery mechanisms. We discuss the rational specification of such protective wrappers in view of system dependability requirements, and highlight some of the design trade-offs and uncertainties that affect system design with OTSCs and wrappers, and that differentiate it from other forms of fault-tolerant design

Preparing fruit and vegetables for winter use

Citation: Riddle, Genevieve L. Preparing fruit and vegetables for winter use. Senior thesis, Kansas State Agricultural College, 1908.Introduction: If the agitation and alarm excited by “Food scandals,” with the details of which the newspapers have reeked lately, have no other permanent result, they have revived the custom of domestic preserving in thousands of households. Canning is hardly fifty years old. It made its way but slowly for a time

Geography, Partisanship, and the Politics of Group Threat.

This dissertation project engages three broad themes in the political behavior literature. First, it addresses the question of political geography, and how the physical arrangement of individuals affects their political attitudes and behavior. Interest in spatial consideration has been growing among political scientists in recent years. Technical advancements have allowed scholars to measure the impact of spatial variables at different geographic levels, but we still have only a limited theoretical understanding of the ways in which different spatial or geographical units become politically meaningful to individuals. I address this issue through an analysis of the impact that physical proximity can have between different racial groups. A second theme this project addresses is the change in the strength and salience of individual attitudes, given those spatial arrangements. In particular, I look at the ways in which spatial arrangements structure and define competition and conflict between groups, and the resulting impact we can observe in group-based antagonisms. Finally, I look at the ways in which the previous two factors combine to shape elite campaign strategy. Given that political campaigns are waged in unique geographic areas, and that group attitudes are powerful influencers on vote choice, I examine the tools that elites will use to manipulate group-based attitudes for political gain. This dissertation addresses these themes through three stand-alone empirical chapters. The data I use consist of elite interviews, national surveys, content analysis of real campaign ads, and spatial demographic data from the U.S. Census. The findings from this project contribute to the racial priming literature, the group threat and racial contact traditions, and the work of scholars who seek to identify and measure campaign effects.PhDPolitical ScienceUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/111544/1/daleal_1.pd

The Relationship between the Distributed Leadership Readiness of West Virginia Principals and Their Perceptions of Selected School-based Committees

The purpose of this study was to determine the relationship between the distributed leadership readiness of West Virginia principals and their perceptions of selected school-based committees which influence leadership in their schools. Six hundred seventy four West Virginia principals were invited to participate in this study by responding to an online survey that included the Distributed Leadership Readiness Scale (DLRS), demographic items, and items from the researcher developed School-Based Committee Influence Survey. There were 198 West Virginia principal respondents to the survey (29.3%). The results of this study showed that West Virginia principal respondents were ready for distributed leadership and saw a relationship with the selected school-based committees. The school leadership team, school curriculum team, and faculty senate were perceived to have the most influence on the leadership of the school. The results showed the school curriculum team with a strong relationship with the perceived level of distributed leadership readiness. Lastly, the results showed that differences existed between some of the demographic factors and perceived level of distributed leadership readiness with some of the DLRS dimensions. Gender had significant differences within the dimensions of School Culture and Shared Responsibility; years of experience in their school had significant differences within the dimensions of Mission, Vision, and Goals and Shared Responsibility; and programmatic level had significant differences with the dimension of Shared Responsibility

Multiplicity of the Galactic Senior Citizens: A high-resolution search for cool subdwarf companions

Cool subdwarfs are the oldest members of the low mass stellar population. Mostly present in the galactic halo, subdwarfs are characterized by their low metallicity. Measuring their binary fraction and comparing it to solar metallicity stars could give key insights into the star formation process early in the history of the Milky Way. However, because of their low luminosity and relative rarity in the solar neighborhood, binarity surveys of cool subdwarfs have suffered from small sample sizes and incompleteness. Previous surveys have suggested that the binary fraction of red subdwarfs is much lower than for their main sequence cousins. Using the highly efficient RoboAO system, we present the largest yet high-resolution survey of subdwarfs, sensitive to angular separations, down to 0.15 arcsec, and contrast ratios, up to 6 magnitude difference, invisible in past surveys. Of 344 target cool subdwarfs, 40 are in multiple systems, 16 newly discovered, for a binary fraction of 11.6 percent and 1.8 percent error. We also discovered 6 triple star systems for a triplet fraction of 1.7 percent and 0.7 percent error. Comparisons to similar surveys of solar metallicity dwarf stars gives a 3 sigma disparity in luminosity between companion stars, with subdwarfs displaying a shortage of low contrast companions.Comment: 13 pages, 10 figures, submitted to Ap