1,081 research outputs found

    Autonomous Commercial Vehicles: The Economic Opportunity in Indiana

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    As part of its future-focused infrastructure planning, INDOT is embarking on a project with Purdue University to understand how the development of transportation infrastructure can be linked to benefits to business supply chains, thus enabling decisions to nurture an ecosystem around connected and autonomous vehicles (CAVs). KPMG will provide insight into the CAV industry

    Thermal energy storage systems using fluidized bed heat exchangers

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    The viability of using fluidized bed heat exchangers (FBHX) for thermal energy storage (TES) in applications with potential for waste heat recovery was investigated. Of the candidate applications screened, cement plant rotary kilns and steel plant electric arc furnaces were identified, via the chosen selection criteria, as having the best potential for successful use of FBHX/TES system. A computer model of the FBHX/TES systems was developed and the technical feasibility of the two selected applications was verified. Economic and tradeoff evaluations in progress for final optimization of the systems and selection of the most promising system for further concept validation are described

    Broadcasting and transmission coordination for ad hoc and sensor networks

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    This thesis studies the performance benefit of coordination in wireless sensor networks (WSNs) and ad hoc networks (AHNs). WSNs are often comprised of a large number of inexpensive nodes with short battery life and limited communication and processing capabilities. AHNs are wireless networks operating without the benefits of network infrastructure (basestations) or centralized control. WSNs often require control messages be broadcast to the entire network. We study the performance of a class of randomized broadcast protocols that employ coordination to reduce the transmission of redundant messages and to reduce the occurrence of message collisions. Specifically, information coordination entails a potential transmitter employ local information to infer whether or not its potential receivers would be interested in its message, while communication coordination entails a potential transmitter employ local information to infer whether or not its transmission would interrupt other ongoing transmissions. The individual and joint benefits of these two forms of coordination are assessed through their impact on a variety of natural performance indicators.AHNs working with limited spectrum perform best when simultaneous transmissions are coordinated to avoid collisions. Optimal transmission coordination is a combinatorial optimization problem that is, in general, intractable for large size networks, even with global information and central control. Constraints on simultaneous transmissions may arise from both transceiver limitations (e.g., half-duplex designs) and from requirements on the signal to interference ratio. We study the transmission coordination optimization problem under a variety of natural communication constraints. Our work identifies particular instances where the problem may be solved by greedy algorithms, and studies the performance of several natural heuristic solutions.Ph.D., Computer Engineering -- Drexel University, 200

    Pre-eclampsia rates in the United States, 1980-2010: age-period-cohort analysis

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    Objective: To estimate the contributions of biological aging, historical trends, and birth cohort effects on trends in pre-eclampsia in the United States. Design: Population based retrospective study. Setting: National hospital discharge survey datasets, 1980-2010, United States. Participants: 120 million women admitted to hospital for delivery. Main outcome measures: Temporal changes in rates of mild and severe pre-eclampsia in relation to maternal age, year of delivery, and birth cohorts. Poisson regression as well as multilevel age-period-cohort models with adjustment for obesity and smoking were incorporated. Results: The rate of pre-eclampsia was 3.4%. The age-period-cohort analysis showed a strong age effect, with women at the extremes of maternal age having the greatest risk of pre-eclampsia. In comparison with women delivering in 1980, those delivering in 2003 were at 6.7-fold (95% confidence interval 5.6-fold to 8.0-fold) increased risk of severe pre-eclampsia. Period effects declined after 2003. Trends for severe pre-eclampsia also showed a modest birth cohort effect, with women born in the 1970s at increased risk. Compared with women born in 1955, the risk ratio for women born in 1970 was 1.2 (95% confidence interval 1.1 to 1.3). Similar patterns were also evident for mild pre-eclampsia, although attenuated. Changes in the population prevalence of obesity and smoking were associated with period and cohort trends in pre-eclampsia but did not explain the trends. Conclusions Rates of severe pre-eclampsia have been increasing in the United States and age-period-cohort effects all contribute to these trends. Although smoking and obesity have driven these trends, changes in the diagnostic criteria may have also contributed to the age-period-cohort effects. Health consequences of rising obesity rates in the United States underscore that efforts to reduce obesity may be beneficial to maternal and perinatal health

    Uteroplacental bleeding disorders during pregnancy: do missing paternal characteristics influence risk?

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    BACKGROUND: Several studies have assessed the risks of uteroplacental bleeding disorders in relation to maternal characteristics. The association between uteroplacental bleeding disorders and paternal characteristics, however, has received considerably less attention. Data on paternal demographics, notably race and age, from birth certificate data are becoming increasingly incomplete in recent years. This pattern of increasingly underreporting of paternal demographic data led us to speculate that pregnancies for which paternal characteristics are partially or completely missing may be associated with increased risk for uteroplacental bleeding disorders. The objective of this study is to examine the association between placenta previa and placental abruption and missing paternal age and race. METHODS: A retrospective cohort study using U.S. linked birth/infant death data from 1995 through 2001 (n = 26,336,549) was performed. Risks of placenta previa and placental abruption among: (i) pregnancies with complete paternal age and race data; (ii) paternal age only missing; (iii) paternal race only missing; and (iv) both paternal age and race missing, were evaluated. Relative risk (RR) with 95% confidence interval (CI) for placenta previa and placental abruption by missing paternal characteristics were derived after adjusting for confounders. RESULTS: Adjusted RR for placental abruption were 1.30 (95% CI 1.24, 1.37), 1.00 (95% CI 0.95, 1.05), and 1.08 (95% CI 1.06, 1.10) among pregnancies with "paternal age only", "paternal race only", and "both paternal age and race" missing, respectively. The increased risk of placental abruption among the "paternal age only missing" category is partly explained by increased risks among whites aged 20–29 years, and among blacks aged ≥30 years. However, no clear patterns in the associations between missing paternal characteristics and placenta previa were evident. CONCLUSION: Missing paternal characteristics are associated with increased risk of placental abruption, likely mediated through low socio-economic conditions
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