In an interference network, multiple transmitters communicate with multiple receivers using the same communication channel. The capacity region of an interference network is defined as the set of data rates that can be simultaneously achieved by the users of the network. One of the most important example of an interference network is the wireless network, where the communication channel is the wireless channel. Wireless interference networks are known to be interference limited rather than noise limited since the interference power level at the receivers (caused by other user's transmissions) is much higher than the noise power level. Most wireless communication systems deployed today employ transmission strategies where the interfering signals are treated in the same manner as thermal noise. Such strategies are known to be suboptimal (in terms of achieving higher data rates), because the interfering signals generated by other transmitters have a structure to them that is very different from that of random thermal noise. Hence, there is a need to design transmission strategies that exploit this structure of the interfering signals to achieve higher data rates. However, determining optimal strategies for mitigating interference has been a long standing open problem. In fact, even for the simplest interference network with just two users, the capacity region is unknown. In this dissertation, we will investigate the capacity region of several models of interference channels. We will derive limits on achievable data rates and design effective transmission strategies that come close to achieving the limits. We will investigate two kinds of networks - "small" (usually characterized by two transmitters and two receivers) and "large" where the number of users is large. / text

No description available.

No description available.

Since the early 1960s, scholars and policymakers have struggled to understand the appropriate role of government in effectively using resources to alleviate poverty. While early U.S. anti-poverty efforts emphasized place-based strategies, such as government-directed infrastructure investments, approaches have gradually shifted to favor civil sector efforts that build community capacity. Efforts to strengthen community capacity have emphasized enhancement of community participation, improvement of governance and strengthening of accountability. Yet, despite the growing emphasis on capacity building, rural regions such as the US-Mexico border region, Appalachia, the Mississippi Delta and Native American country have remained poor.This dissertation argues that government institutions have failed to improve conditions in poor, rural regions because current efforts ignore the broader context and fail to understand the needs of both formal organizations and informal participants. This research argues that without an adequate conceptual framework for assessing these three factors - the structural environment, community-based organizations, and local society -- federal investments cannot change local conditions. A conceptual model integrating these factors is applied to the case of poor, unincorporated colonias located in Arizona and New Mexico counties bordering Mexico. The empirical application of the conceptual model relies on methods integrating both regional and local analysis. The regional analysis is used to develop a socioeconomic index of deprivation. The index accomplishes two objectives. First, it reveals patterns of deprivation, uncovering the relationship between the impact of location (proximity to metropolitan and border areas) on the level of socioeconomic deprivation. Second, it is applied to select five cases for further analysis. The local analysis integrates qualitative research and formal social network methods. Unlike other studies of community capacity, which mostly rely on qualitative case studies, formal social network analysis is used to identify structural differences regarding how community organizations and individuals build autonomy and linkage with local and non-local organizations to improve the quality of life.This research improves understanding - both from conceptual and methodological perspectives -- of how to analyze rural poverty so as to better design federal government programs that will better serve poor communities, especially those in unincorporated areas.

Background: The high frequency of emergency responses and the variety of response environments for firefighting and emergency medical services dictate a potential for high work demands and an increasing need for maintaining above average physical fitness. This study makes use of a retrospective occupational cohort study design to explore the relationships between measures of fitness and injury outcomes. Methods: Data were collected from annual medical exams and injury surveillance records recorded for the years 2004-2009 among commissioned employees of the Tucson Fire Department. Fitness was assessed and contrasted via a submaximal estimate of aerobic capacity and a developed metric and score for comprehensive "fire fitness" encompassing seven separate measures for strength, endurance, flexibility, body composition and aerobic fitness. Individual fitness scores were classified as 'high fit', 'fit', and 'less fit'. The association between the fitness measures and injuries was evaluated using two approaches: log-binomial and time-to-event analyses. Results: The annual injury incidence rate averaged 17.7 per 100 employees. One-third of all injuries (32.9%) resulted from physical exercise activities, while patient transport, training drills, and fireground operations resulted in 16.9%, 11.1% and 10.2% of injuries, respectively. For all job operations, sprains and strains were the most prevalent type of injury, followed by contusions and lacerations. The reliability of fitness and clinical measures showed mean flexibility, grip strength, percent body fat, and resting heart rate each had intraclass correlations (ICC) values above 0.5, suggesting fair to good reliability. In contrast, mean VO2max was an unreliable measure with an ICC of 0.27. Hazard ratios from time-to-event analyses indicated that increases in cardiorespiratory fitness were significantly associated with decreased risk against injury. Similarly, decreases in comprehensive "fire fitness" were associated with an increased risk of injury. Conclusions: These findings add support that improving one's fitness reduces the likelihood of injury. Future research should focus on the relationship between fitness, performance and health outcomes. Individual level fitness improvements should be objectively measured and designed within the functional limitations of that individual, and without subjecting the person to injury in that process.

No description available.

No description available.

No description available.

Disertacijoje nagrinėjama tematika yra susijusi su superkondensatorių formavimu ir jų tyrimais naudojant plazmines technologijas. Superkondensatorių elektrodams formuoti panaudota plazminio purškimo technologija. Anglis ant nerūdijančio plieno paviršiaus užnešta panaudojant atmosferinio slėgio argono-acetileno plazmą. Nikelio oksidui nusodinti ant anglies elektrodų paviršiaus panaudotas magnetroninio garinimo metodas. Įvertinta acetileno kiekio įtaka superkondensatorių elektrinėms charakteristikoms ir elektrodų struktūrai. Tai pat įvertinta nikelio oksido kiekio įtaka superkondensatorių anglies elektrodų elektriniams parametrams, struktūrai bei mikroreljefui. Atliktas anglies elektrodų paviršiaus ėsdinimas deguonies plazma ir įvertintas jo poveikis kondensatorių elektriniams parametrams ir anglies elektrodų struktūrai. Matematiniu modeliavimu teoriškai įvertinta deguonies plazmos įtaka superkondensatorių anglies elektrodų paviršiaus mikroreljefui. Teoriškai pagrįstas anglies dangos reljefo anizotropinis augimas ir izotropinės paviršiaus erozijos mechanizmas. Kokybiškai paaiškintas acetileno kiekio ir plazmotrono galios įtakos mechanizmas anglies elektrodų struktūrai ir elektriniams parametrams. Pasiūlytas mechanizmas, aiškinantis NiO kiekio, esančio ant anglies elektrodų, įtaką superkondensatorių elektriniams parametrams ir elektrodų struktūrai. / The dissertation examines topics related to the formation of supercapacitors using plasma technology and their analysis. Plasma spray technology was used to form supercapacitors electrodes. Carbon was deposited on stainless steel surface using the atmospheric pressure argon-acetylene plasma. The deposition of nickel oxide on the surface of carbon electrodes was made using magnetron sputtering method. The influence of acetylene amount to the supercapacitors electrodes and the electrical characteristics of the structure were estimated. The nickel oxide influence to the electrical parameters of supercapacitor carbon electrodes, structure and microrelief was assessed too. The etching of carbon electrodes surface with oxygen plasma was performed and its impact on the capacitors electrical parameters and carbon electrode structure was evaluated. Mathematical modeling was used to theoretically estimate the influence of oxygen plasma to the supercapacitor carbon electrode surface microrelief. The anisotropic growth of carbon surface relief and isotropic surface erosion mechanism was theoretically explained. The impact mechanism of the acetylene content and plasmatron power to the carbon electrode structure and electrical parameters was qualitatively explained. The mechanism for understanding the influence of NiO content on the carbon electrodes to the supercapacitor electrical parameters and electrode structure was proposed.

No description available.