Purdue University

About: Purdue University is a education organization based out in West Lafayette, Indiana, United States. It is known for research contribution in the topics: Population & Context (language use). The organization has 73219 authors who have published 163563 publications receiving 5775236 citations. The organization is also known as: Purdue & Purdue-West Lafayette.

Log-concave probability and its applications

Abstract: In many applications, assumptions about the log-concavity of a probability distribution allow just enough special structure to yield a workable theory. This paper catalogs a series of theorems relating log-concavity and/or log-convexity of probability density functions, distribution functions, reliability functions, and their integrals. We list a large number of commonly-used probability distributions and report the log-concavity or log-convexity of their density functions and their integrals. We also discuss a variety of applications of log-concavity that have appeared in the literature.

Dynamic Performance of a Modular Multilevel Back-to-Back HVDC System

Abstract: The modular multilevel converter (MMC) is a newly introduced switch-mode converter topology with the potential for high-voltage direct current (HVDC) transmission applications. This paper focuses on the dynamic performance of an MMC-based, back-to-back HVDC system. A phase-disposition (PD) sinusoidal pulsewidth modulation (SPWM) strategy, including a voltage balancing method, for the operation of an MMC is presented in this paper. Based on the proposed PD-SPWM switching strategy, a mathematical model for the MMC-HVDC system, under both balanced and unbalanced grid operation modes, is developed. Dynamic performance of the MMC-based back-to-back HVDC converter system, based on time-domain simulation studies in the PSCAD/EMTDC environment, is then evaluated. The reported time-domain simulation results show that based on the adopted PD-SPWM switching strategy, the MMC-HVDC station can respond satisfactorily to the system dynamics and control commands under balanced and unbalanced conditions while maintaining voltage balance of the dc capacitors.

Social Capital and Community Resilience

Abstract: Despite the ubiquity of disaster and the increasing toll in human lives and financial costs, much research and policy remain focused on physical infrastructure–centered approaches to such events. Governmental organizations such as the Department of Homeland Security, United States Federal Emergency Management Agency, United States Agency for International Development, and United Kingdom’s Department for International Development continue to spend heavily on hardening levees, raising existing homes, and repairing damaged facilities despite evidence that social, not physical, infrastructure drives resilience. This article highlights the critical role of social capital and networks in disaster survival and recovery and lays out recent literature and evidence on the topic. We look at definitions of social capital, measurement and proxies, types of social capital, and mechanisms and application. The article concludes with concrete policy recommendations for disaster managers, government decision makers, and no...

Plant Volatiles: Recent Advances and Future Perspectives

Abstract: Volatile compounds act as a language that plants use for their communication and interaction with the surrounding environment. To date, a total of 1700 volatile compounds have been isolated from more than 90 plant families. These volatiles, released from leaves, flowers, and fruits into the atmosphere and from roots into the soil, defend plants against herbivores and pathogens or provide a reproductive advantage by attracting pollinators and seed dispersers. Plant volatiles constitute about 1% of plant secondary metabolites and are mainly represented by terpenoids, phenylpropanoids/benzenoids, fatty acid derivatives, and amino acid derivatives. In this review we focus on the functions of plant volatiles, their biosynthesis and regulation, and the metabolic engineering of the volatile spectrum, which results in plant defense improvement and changes of scent and aroma properties of flowers and fruits.