Kriging-Weighted Laplacian Kernels

<div>Laplacian kernels, which are widely used as sharpening filters in image processing, are isotropic and tend to over-highlight fine details with a sharp discontinuity in images. To address this issue, this paper introduces a method that integrates anisotropic averaging with the Laplacian kernels. </div><div>The proposed method can also be useful as a new type of image convolution for designing convolutional neural networks. </div>

Kriging-Weighted Laplacian Kernels

<div>Laplacian kernels, which are widely used as sharpening filters in image processing, are isotropic and tend to over-highlight fine details with a sharp discontinuity in images. To address this issue, this paper introduces a method that integrates anisotropic averaging with the Laplacian kernels. </div><div>The proposed method can also be useful as a new type of image convolution for designing convolutional neural networks. </div>

Return-to-Work Policies and Labor Supply in Disability Insurance Programs

Return-to-work policies in disability insurance (DI) programs allow beneficiaries to collect a portion of their benefits while working. I investigate whether a large increase in incentives to work in a return-to-work policy could induce benefit recipients to increase their labor supply. I quantify the effects on earnings and labor force participation using a sharp discontinuity in the induced incentives to work at the month of the policy change in a DI program in Canada. Using administrative data, I document that large incentives to work could induce beneficiaries to increase their labor supply both in intensive and extensive margins.

The Distortionary Effects of Incentives in Government: Evidence from China's “Death Ceiling” Program

We study a 2004 program designed to motivate Chinese bureaucrats to reduce accidental deaths. Each province received a set of “death ceilings” that, if exceeded, would impede government officials' promotions. For each category of accidental deaths, we observe a sharp discontinuity in reported deaths at the ceiling, suggestive of manipulation. Provinces with safety incentives for municipal officials experienced larger declines in accidental deaths, suggesting complementarities between incentives at different levels of government. While realized accidental deaths predict the following year's ceiling, we observe no evidence that provinces manipulate deaths upward to avoid ratchet effects in the setting of death ceilings. (JEL D73, J28, J45, J81, O15, P26, P36)

How Financial Incentives Induce Disability Insurance Recipients to Return to Work

Using a local randomized experiment that arises from a sharp discontinuity in Disability Insurance (DI) policy in Norway, we provide transparent and credible identification of how financial incentives induce DI recipients to return to work. We find that many DI recipients have considerable capacity to work that can be effectively induced by providing financial work incentives. We further show that providing work incentives to DI recipients may both increase their disposable income and reduce program costs. Our findings also suggest that targeted policies may be the most effective in encouraging DI recipients to return to work. (JEL D14, H55, J14, J22, J28)

The Leisure Pursuits of Brisbane Children During the 1930s Depression

Neighbourhood children played lots of games together … no expensive material required … As there was no Presbyterian Church I went to the Methodist Sunday School. This church had a social evening of games every Friday night. Nobody worried about what religion we were, and we would all come home singing along the road.—Les B and Jean H, children of the DepressionOver the last 30 years, many books have appeared on different aspects of childhood in Australia. There has not, however, been an authoritative published history of childhood that is specific to the Depression years. Sue Fabian and Morag Loh'sChildren in Australia: An Outline Historyand Jan Kociumbas'sAustralian Childhood: A Historyinclude chapters that offer overviews of Australian childhood during the Depression, and Lynette Finch's special issue ofQueensland Review, Young in a Warm Climate, is the only major study specific to children in Queensland. This paper makes a contribution to Queensland Depression historiography and the history of Queensland children by exploring how the children of Brisbane's working-class unemployed spent their leisure hours, and what effect — if any — the Depression exerted over the choices that were made. It will show mat there was neither uniformity of experience nor a sharp discontinuity between the Depression years and those that preceded and followed this decade.

A Discontinuity in the Distribution of Fixed Point Sums

The quantity $f(n,r)$, defined as the number of permutations of the set $[n]=\{1,2,\dots n\}$ whose fixed points sum to $r$, shows a sharp discontinuity in the neighborhood of $r=n$. We explain this discontinuity and study the possible existence of other discontinuities in $f(n,r)$ for permutations. We generalize our results to other families of structures that exhibit the same kind of discontinuities, by studying $f(n,r)$ when "fixed points" is replaced by "components of size 1" in a suitable graph of the structure. Among the objects considered are permutations, all functions and set partitions.

Shocks in sand flowing in a silo

We study the formation of shocks on the surface of a granular material draining through an orifice at the bottom of a quasi-two-dimensional silo. At high flow rates, the surface is observed to deviate strongly from a smooth linear inclined profile, giving way to a sharp discontinuity in the height of the surface near the bottom of the incline, the typical response of a choking flow such as encountered in a hydraulic jump in a Newtonian fluid like water. We present experimental results that characterize the conditions for the existence of such a jump, describe its structure and give an explanation for its occurrence.

On the solution of the problem of scattering of surface water waves by a sharp discontinuity in the surface boundary conditions

Closed-form analytical expressions are derived for the reflection and transmission coefficients for the problem of scattering of surface water waves by a sharp discontinuity in the surface-boundary-conditions, for the case of deep water. The method involves the use of the Havelock-type expansion of the velocity potential along with an analysis to solve a Carleman-type singular integral equation over a semi-infinite range. This method of solution is an alternative to the Wiener-Hopf technique used previously.