A joint probability approach to flood frequency estimation using Monte Carlo simulation

In the UK, flood estimation using event based rainfall–runoff modelling currently assigns pre-defined design values to the input variables which control the size of the flow events, apart from the rainfall magnitude which is treated as a random variable. The use of design values, rather than allowing the variables to be described by their full probability distribution, is a practical simplification but may lead to biases in the output flood magnitudes. The present study simulates a large number of flow events using sets of input variables from distributions fitted to observed event data, taking into account seasonality. These simulated datasets are used for running a rainfall-runoff model, and a frequency analysis is applied to the peaks of the output flow hydrographs. The simulated inputs are the rainfall intensity and duration, and the soil moisture deficit (SMD) and initial river flow at the beginning of the rainfall event. An inter-event arrival time is simulated so that a series of events is obtained. The initial conditions of SMD and river flow of each event are made dependent on the (simulated) time elapsed since the previous event, and on the SMD at the end of the previous event

Estimating Returns to Schooling When Schooling is Misreported

We propose a general method of moments technique to identify measurement error in self-reported and transcript-reported schooling using differences in wages, test scores, and other covariates to discern the relative verity of each measure. We also explore the implications of such reporting errors for both OLS and IV estimates of the returns to schooling. The results cast a new light on two common findings in the extensive literature on the returns to schooling: sheepskin effects' and the recent IV estimates, relying on natural experiments' to identify the payoff to schooling. First, respondents tend to self-report degree attainment much more accurately than they report educational attainment not corresponding with degree attainment. For instance, we estimate that more than 90 percent of those with associate's or bachelor's degrees accurately report degree attainment, while only slightly over half of those with 1 or 2 years of college credits accurately report their educational attainment. As a result, OLS estimates tend to understate returns per year of schooling and overstate degree effects. Second, because the measurement error in educational attainment is non-classical, IV estimates also tend to be biased, although the magnitude of the bias depends upon the nature of the measurement error in the region of educational attainment affected by the instrument.

Fast time variations of supernova neutrino fluxes and their detectability

In the delayed explosion scenario of core-collapse supernovae (SNe), the accretion phase shows pronounced convective overturns and a low-multipole hydrodynamic instability, the standing accretion shock instability (SASI). These effects imprint detectable fast time variations on the emerging neutrino flux. Among existing detectors, IceCube is best suited to this task, providing an event rate of ~1000 events per ms during the accretion phase for a fiducial SN distance of 10 kpc, comparable to what could be achieved with a megaton water Cherenkov detector. If the SASI activity lasts for several hundred ms, a Fourier component with an amplitude of 1% of the average signal clearly sticks out from the shot noise. We analyze in detail the output of axially symmetric hydrodynamical simulations that predict much larger amplitudes up to frequencies of a few hundred Hz. If these models are roughly representative for realistic SNe, fast time variations of the neutrino signal are easily detectable in IceCube or future megaton-class instruments. We also discuss the information that could be deduced from such a measurement about the physics in the SN core and the explosion mechanism of the SN.Comment: 14 pages, 11 figures. Final version accepted in PRD. Section on astrophysical relevance and several references adde

A bistable soft gripper with mechanically embedded sensing and actuation for fast closed-loop grasping

Soft robotic grippers are shown to be high effective for grasping unstructured objects with simple sensing and control strategies. However, they are still limited by their speed, sensing capabilities and actuation mechanism. Hence, their usage have been restricted in highly dynamic grasping tasks. This paper presents a soft robotic gripper with tunable bistable properties for sensor-less dynamic grasping. The bistable mechanism allows us to store arbitrarily large strain energy in the soft system which is then released upon contact. The mechanism also provides flexibility on the type of actuation mechanism as the grasping and sensing phase is completely passive. Theoretical background behind the mechanism is presented with finite element analysis to provide insights into design parameters. Finally, we experimentally demonstrate sensor-less dynamic grasping of an unknown object within 0.02 seconds, including the time to sense and actuate

Paying for performance: the education impacts of a community college scholarship program for low-income adults

We evaluate educational outcomes from an experiment which randomly assigned performancebased scholarship eligibility to students on community college campuses. Scholarships were awarded in three payments each semester over the course of two semesters. Payments were tied to students meeting two conditions—enrolling at least half time and maintaining a “C” or better semester grade point average. We find that the program increased the likelihood a student was enrolled at the program institutions in both the first and second semesters after random assignment and increased the total number of credits attempted and earned each semester. One year after random assignment, program group students were more likely to persist at their program institution, and one and two years after random assignment, program group students had completed 3-4 credits more than the control group students. We find little evidence that program eligibility induced students to change the types of courses taken but some evidence that the program may have increased academic performance and effort conditional on enrollment.Education - Economic aspects ; Income

Rewarding Persistence: Effects of a Performance-Based Scholarship Program for Low-Income Parents

This report describes the impacts of a performance-based scholarship program with a counseling component on academic success and persistence among low-income parents. Students who participated in the program, which was operated at two New Orleans-area colleges as part of MDRC's multisite Opening Doors demonstration, were more likely to stay in school, get higher grades, and earn more credits

Using visual analytics to develop situation awareness in astrophysics

We present a novel collaborative visual analytics application for cognitively overloaded users in the astrophysics domain. The system was developed for scientists who need to analyze heterogeneous, complex data under time pressure, and make predictions and time-critical decisions rapidly and correctly under a constant influx of changing data. The Sunfall Data Taking system utilizes several novel visualization and analysis techniques to enable a team of geographically distributed domain specialists to effectively and remotely maneuver a custom-built instrument under challenging operational conditions. Sunfall Data Taking has been in production use for 2 years by a major international astrophysics collaboration (the largest data volume supernova search currently in operation), and has substantially improved the operational efficiency of its users. We describe the system design process by an interdisciplinary team, the system architecture and the results of an informal usability evaluation of the production system by domain experts in the context of Endsley's three levels of situation awareness

Are flight paths of nocturnal songbird migrants influenced by local coastlines at a peninsula?

By recording nocturnally migrating passerines with tracking radar we have investigated how coastlines affect the migrants’ flight paths. Birds could use coastlines as an orientation aid or as a reference cue to compensate for wind drift while migrating. However, on the small scale of Falsterbo Peninsula in southern Sweden, we found very little effect of coastlines on migrants flight paths, irrespective of altitude. We tracked 2 930 migrants in three autumn and two spring seasons, at altitudes from 60 up to 3 000 meters. We compared tracks of migrants flying in three different areas, which correspond to the three main coastlines, and can demonstrate that the orientation of the tracks did not differ in a way consistent with the coastlines between the areas in autumn, and showed only a slight effect in spring. This is in accordance with earlier infrared device monitoring in Falsterbo, but contrary to earlier visual observations. It supports the view of nocturnally migrating passerines as mainly broad-front migrants. Even though the coastlines on the scale of the peninsula affected the flight paths very little, it is possible that the coastline has an effect on a larger regional scale, by migrants avoiding long sea crossings and thereby being funneled towards the peninsula, but this remains to be investigated

Use-oriented business model

In a world of sustainability challenges, use-oriented product-service system seems promising to encourage resource efficiency. For this project, the concept is integrated in a sustainability-oriented interpretation of the business model Canvas. The aim was to identify enabling factors with a use-oriented business model. A case study was conducted on rental business models in the outdoors apparel industry in Scandinavia. The key findings indicate that companies introducing use-oriented services struggle with increased transportation, linear technological systems, large financial capital needs and cultural barriers. To overcome these challenges the case study points to the importance of partnerships. Furthermore, this paper suggests expanding the Business Model Canvas framework with three additional elements: reduced material flows, reverse logistics and cultural adoption factor. The extended Canvas model can be used as a conceptual tool for companies when developing rental services