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 & Heat transfer. The organization has 73219 authors who have published 163563 publications receiving 5775236 citations. The organization is also known as: Purdue & Purdue-West Lafayette.

The design and implementation of tripwire: a file system integrity checker

Abstract: At the heart of most computer systems is a file system. The file system contains user data, executable programs, configuration and authorization information, and (usually) the base executable version of the operating system itself. The ability to monitor file systems for unauthorized or unexpected changes gives system administrators valuable data for protecting and maintaining their systems. However, in environments of many networked heterogeneous platforms with different policies and software, the task of monitoring changes becomes quite daunting.Tripwire is tool that aids UNIX system administrators and users in monitoring a designated set of files and directories for any changes. Used with system files on a regular (e.g., daily) basis, Tripwire can notify system administrators of corrupted or altered files, so corrective actions may be taken in a timely manner. Tripwire may also be used on user or group files or databases to signal changes.This paper describes the design and implementation of the Tripwire tool. It uses interchangeable “signature” (usually, message digest) routines to identify changes in files, and is highly configurable. Tripwire is no-cost software, available on the Internet, and is currently in use on thousands of machines around the world.

Ultra-thin, planar, Babinet-inverted plasmonic metalenses

Abstract: Scientists in the USA have developed powerful ultrathin planar lenses made from 30-nm-thick perforated gold films. These plasmonic metalenses, created by Xingjie Ni and co-workers at Purdue University, focus a beam of visible light into a spot measuring only slight larger than the wavelength of operation. The devices rely on a concentric pattern of Babinet-inverted nano-antennas (nano-avoids) in a metal film that manipulate the phase of the incident light. For example, a 4-μm-diameter lens provides a focal length of 2.5 μm at a wavelength of 676 nm. The lenses are designed to work at two orthogonal linear polarizations and in future could be suitable for use as miniature couplers or light concentrators in on-chip optical devices.

Commitment and its theorized determinants: A meta–analysis of the Investment Model

Abstract: We conducted a meta-analysis of Rusbult’s Investment Model of commitment. Across 52 studies, including 60 independent samples and 11,582 participants, satisfaction with, alternatives to, and investments in a relationship each correlated significantly with commitment to that relationship. Moreover, these three variables collectively accounted for nearly two-thirds of the variance in commitment. Commitment, in turn, was found to be a significant predictor of relationship breakup. Support for the model was obtained in predicting commitment in both relational domains (e.g., commitment to a romantic partnership) and nonrelational domains (e.g., commitment to one’s job), but was significantly stronger in relational domains. Additional moderator analyses suggested that the associations between commitment and its theorized bases vary minimally as a function of demographic (e.g., ethnicity) or relational (e.g., duration) factors. We review theoretical strengths and shortcomings of the Investment Model and identify directions for future research. Research on social psychological dimensions

Observation and studies of jet quenching in PbPb collisions at √sNN=2.76 TeV

Abstract: Jet production in PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV was studied with the CMS detector at the LHC, using a data sample corresponding to an integrated luminosity of 6.7 inverse microbarns. Jets are reconstructed using the energy deposited in the CMS calorimeters and studied as a function of collision centrality. With increasing collision centrality, a striking imbalance in dijet transverse momentum is observed, consistent with jet quenching. The observed effect extends from the lower cut-off used in this study (jet transverse momentum = 120 GeV/c) up to the statistical limit of the available data sample (jet transverse momentum approximately 210 GeV/c). Correlations of charged particle tracks with jets indicate that the momentum imbalance is accompanied by a softening of the fragmentation pattern of the second most energetic, away-side jet. The dijet momentum balance is recovered when integrating low transverse momentum particles distributed over a wide angular range relative to the direction of the away-side jet.

Effectiveness of Low Impact Development Practices: Literature Review and Suggestions for Future Research

Abstract: Low impact development (LID) is a land development strategy for managing stormwater at the source with decentralized micro-scale control measures. Since the emergence of LID practices, they have been successfully used to manage stormwater runoff, improve water quality, and protect the environment. However, discussions still surround the effectiveness of many of these practices, resulting in a reluctance to widely adopt them. This paper highlights evidence in the literature regarding the beneficial uses of LID practices. A discussion of how LID practices are represented in hydrologic/water quality models is also provided using illustrative examples of three computational models developed with algorithms and modules to support widespread adoption of LID practices. Finally, the paper suggests directions for future research opportunities.