3,527 research outputs found

    Convenience or reckless spending? How mobile payment apps can help college students manage their money

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    Mobile payment service (MPS) apps are often used because they are convenient and easy to use. However, some people may not understand how MPS use could impact day-to-day finances or long-term financial well-being. This study seeks to explore the use of MPS apps among college students. It is hypothesized that MPS app use is related to factors such as ease of use, convenience, and financial behaviors, such as monitoring spending or paying bills on time. In the fall of 2021, 122 college students from the Southeastern United States responded to an online Qualtrics questionnaire related to preferences among MPS apps, frequency of their use, and spending and bill-paying financial behaviors in the last 6 months. Responses were coded and analyzed by using IBM SPSS v 28. Correlations revealed frequent MPS use was not associated with financial skills, usefulness, convenience, awareness, or actual financial behaviors. However, financial skills were positively related to factors such as MPS usefulness (r = .62, p ā‰¤ .001) and convenience (r = .58, p ā‰¤ .001), and awareness of financial behaviors (r = .55, p ā‰¤ .001). Findings suggest that MPS apps can be a tool to promote financial management behaviors such as controlling spending and paying bills on time

    Student Experience: Development Management consultancy project presents report to leaders in the field

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    A small team of students from the MSc Development Management 2015/2016 course presented a successful report last week in collaboration with Charities Aid Foundation at the pre-launch event for their research. Silky Agrawal, Brooks Reed, and Riya Saxena share their experiences

    Robust minimum energy wireless routing for underwater acoustic communication networks

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    Marine robots are an increasingly attractive means for observing and monitoring the ocean, but underwater acoustic communications remain a major challenge. The channel exhibits long delay spreads with frequency-dependent attenuation; moreover, it is time-varying. We consider the minimum energy wireless transmission problem [MET], augmented by the practical condition that constraints on link power must be satisfied in probability. For this, we formulate the robust counterpart of the multicommodity mixed-integer linear programming (MILP) model from Haugland and Yuan [1], and derive scaled power levels that account for uncertainty. Our main result is that the deterministic formulation with these scaled power levels recovers exactly the optimal robust solution in the absence of correlations, and therefore allows for efficient solution via MILP. This approach achieves significant power improvements over heuristics, and naturally lends itself to vehicle networks.United States. Office of Naval Research (Grant N00014-09-1-0700

    Multiple-vehicle resource-constrained navigation in the deep ocean

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    Thesis (S.M.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and the Woods Hole Oceanographic Institution), 2011.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. 139-148).This thesis discusses sensor management methods for multiple-vehicle fleets of autonomous underwater vehicles, which will allow for more efficient and capable infrastructure in marine science, industry, and naval applications. Navigation for fleets of vehicles in the ocean presents a large challenge, as GPS is not available underwater and dead-reckoning based on inertial or bottom-lock methods can require expensive sensors and suffers from drift. Due to zero drift, acoustic navigation methods are attractive as replacements or supplements to dead-reckoning, and centralized systems such as an Ultra-Short Baseline Sonar (USBL) allow for small and economical components onboard the individual vehicles. Motivated by subsea equipment delivery, we present model-scale proof-of-concept experimental pool tests of a prototype Vertical Glider Robot (VGR), a vehicle designed for such a system. Due to fundamental physical limitations of the underwater acoustic channel, a sensor such as the USBL is limited in its ability to track multiple targets-at best a small subset of the entire fleet may be observed at once, at a low update rate. Navigation updates are thus a limited resource and must be efficiently allocated amongst the fleet in a manner that balances the exploration versus exploitation tradeoff. The multiple vehicle tracking problem is formulated in the Restless Multi-Armed Bandit structure following the approach of Whittle in [108], and we investigate in detail the Restless Bandit Kalman Filters priority index algorithm given by Le Ny et al. in [71]. We compare round-robin and greedy heuristic approaches with the Restless Bandit approach in computational experiments. For the subsea equipment delivery example of homogeneous vehicles with depth-varying parameters, a suboptimal quasi-static approximation of the index algorithm balances low landing error with safety and robustness. For infinite-horizon tracking of systems with linear time-invariant parameters, the index algorithm is optimal and provides benefits of up to 40% over the greedy heuristic for heterogeneous vehicle fleets. The index algorithm can match the performance of the greedy heuristic for short horizons, and offers the greatest improvement for long missions, when the infinite-horizon assumption is reasonably met.by Brooks Louis-Kiguchi Reed.S.M

    Nonlinear Relaxation Dynamics in Elastic Networks and Design Principles of Molecular Machines

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    Analyzing nonlinear conformational relaxation dynamics in elastic networks corresponding to two classical motor proteins, we find that they respond by well-defined internal mechanical motions to various initial deformations and that these motions are robust against external perturbations. We show that this behavior is not characteristic for random elastic networks. However, special network architectures with such properties can be designed by evolutionary optimization methods. Using them, an example of an artificial elastic network, operating as a cyclic machine powered by ligand binding, is constructed.Comment: 12 pages, 9 figure

    Oceanographic pursuit: Networked control of multiple vehicles tracking dynamic ocean features

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    We present an integrated framework for joint estimation and pursuit of dynamic features in the ocean, over large spatial scales and with multiple collaborating vehicles relying on limited communications. Our approach uses ocean model predictions to design closed-loop networked control at short time scales, and the primary innovation is to represent model uncertainty via a projection of ensemble forecasts into local linearized vehicle coordinates. Based on this projection, we identify a stochastic linear time-invariant model for estimation and control design. The methodology accurately decomposes spatial and temporal variations, exploits coupling between sites along the feature, and allows for advanced methods in communication-constrained control. Simulations with three example datasets successfully demonstrate the proof-of-concept.United States. Office of Naval Research (Grant N00014-09-1-0700)National Science Foundation (U.S.) (Contract CNS-1212597

    Influence of oxidation on fatigue crack initiation and propagation in turbine disc alloy N18

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    Fatigue crack initiation and propagation behaviour in subsolvus heat treated turbine disc alloy N18 has been assessed in air and vacuum at 650 and 725oC under three-point loading. Fatigue crack initiation processes have been evaluated using single edge U-notch specimens under a 1-1-1-1 trapezoidal loading waveform along with interrupted tests at 650oC to allow intermittent observations of the notch surface. The results show apparent grain boundary (GB) oxidation can occur under an oxygen partial pressure of 10-2?10-3Pa. Cracks mainly initiate from grain boundaries or ?/?? interfaces due to the formation and subsequent cracking of Cr-rich and/or Co-rich oxides, and occasionally initiate from surface pores. Fatigue life in these tests appears to be dominated by this crack initiation process and is significantly reduced by increasing temperature and/or application of an oxidizing environment. Crack growth tests conducted under 1-1-1-1 and 1-20-1-1 loading waveforms indicate that oxidation significantly degrades the crack growth resistance of N18 and is associated with more intergranular fracture surface features. Additional oxidation effects on propagation caused by higher temperature or prolonging dwell time appear limited, whereas a prolonged dwell period seems to instead promote additional creep process, which further enhance crack growth, especially at higher temperature

    Experiments in dynamic control of autonomous marine vehicles using acoustic modems

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    Marine robots are an increasingly attractive means for observing and monitoring in the ocean, but underwater acoustic communication (ā€œacommsā€) remains a major challenge, especially for real-time control. Packet loss occurs widely, bit rates are low, and there are significant delays. We consider here strategies for feedback control with acomms links in either the sensor-controller channel, or the controller-actuator channel. On the controller-actuator side we implement sparse packetized predictive control (S-PPC), which simultaneously addresses packet-loss and the data rate limit. For the sensor-controller channel we study a modified information filter (MIF) in a Linear Quadratic Gaussian (LQG) control scheme. Field experiments were carried out with both approaches, regulating crosstrack error in a robotic kayak using acomms. Outcomes with both the S-PPC and MIF LQG confirm that good performance is achievable.United States. Office of Naval Research (Grant N00014-09-1-0700)National Science Foundation (U.S.) (Contract CNS-1212597)Finmeccanic

    Faint dwarfs as a test of DM models: WDM vs. CDM

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    We use high resolution Hydro++N-Body cosmological simulations to compare the assembly and evolution of a small field dwarf (stellar mass ~ 106āˆ’7^{6-7} MāŠ™\odot, total mass 1010^{10} MāŠ™\odot in Ī›\Lambda dominated CDM and 2keV WDM cosmologies. We find that star formation (SF) in the WDM model is reduced and delayed by 1-2 Gyr relative to the CDM model, independently of the details of SF and feedback. Independent of the DM model, but proportionally to the SF efficiency, gas outflows lower the central mass density through `dynamical heating', such that all realizations have circular velocities << 20kms at 500Ā ~pc, in agreement with local kinematic constraints. As a result of dynamical heating, older stars are less centrally concentrated than younger stars, similar to stellar population gradients observed in nearby dwarf galaxies. Introducing an important diagnostic of SF and feedback models, we translate our simulations into artificial color-magnitude diagrams and star formation histories in order to directly compare to available observations. The simulated galaxies formed most of their stars in many āˆ¼\sim10 Myr long bursts. The CDM galaxy has a global SFH, HI abundance and Fe/H and alpha-elements distribution well matched to current observations of dwarf galaxies. These results highlight the importance of directly including `baryon physics' in simulations when 1) comparing predictions of galaxy formation models with the kinematics and number density of local dwarf galaxies and 2) differentiating between CDM and non-standard models with different DM or power spectra.Comment: 13 pages including Appendix on Color Magnitude Diagrams. Accepted by MNRAS. Added one plot and details on ChaNGa implementation. Reduced number of citations after editorial reques

    A Model Description for the Transition from Multiprofessional to Interprofessional Courses

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    Transitioning from multiprofessional to interprofessional courses requires a commitment on behalf of the faculty of the programs represented within these courses. Through the development of advisory committees, creation and implementation of curricula, obtainment of pre- and post-test data and course evaluations this transition can be achieved. The Pathologistsā€™ Assistant Department at Rosalind Franklin University of Medicine and Science is currently involved in a transition of many of its studentsā€™ courses from multiprofessional to interprofessional; one such example is the Neuroscience course which combines Pathologistsā€™ Assistant, Physical Therapy, and Podiatry students. This transition includes the formation of an advisory group, review of course objectives, participation by faculty from each program represented in the course, the collaborative development of syllabi and exams, having students work in interprofessional teams analyzing case studies relevant to each profession, and involvement in a demonstration laboratory. This presentation will focus on our model currently being used atRosalindFranklinUniversityin transitioning from multiprofessional to interprofessional courses. We will discuss our successes and also the challenges we face in this transition process. Learning Objectives: At the end of this session, participants will: 1. Discuss the components involved in transitioning from multiprofessional to interprofessional courses. 2. Identify potential barriers in the transition process
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