Quickshift++: Provably Good Initializations for Sample-Based Mean Shift

We provide initial seedings to the Quick Shift clustering algorithm, which approximate the locally high-density regions of the data. Such seedings act as more stable and expressive cluster-cores than the singleton modes found by Quick Shift. We establish statistical consistency guarantees for this modification. We then show strong clustering performance on real datasets as well as promising applications to image segmentation.Comment: ICML 2018. Code release: https://github.com/google/quickshif

Demographic Dividends, Human Capital, and Saving.

The objective of this paper is to provide new evidence about the development effects of changes in population age structure and human and physical capital. This extends our previous work by developing and employing a more comprehensive model of demographic dividends. In addition, we extend earlier analysis about the quantity-quality tradeoff using newly available NTA data for 39 countries, in contrast to the nineteen with the necessary data in our 2010 study. This permits a more detailed analysis, treating public expenditures and private expenditures separately, and considering the role of per capita income as well as fertility and child dependency in relation to human capital spending. The analysis is used in a simulation with realistic demography to show how human capital investment has varied in relation to the changing demography from 1950 to the present, and how it might be expected to change over the rest of this century. These new estimates are then used in a more comprehensive model that incorporates both human and physical capital. The analysis provides estimates of the first and second demographic dividends and how they are affected by speed of fertility decline. The timing of the effects is documented and the relative importance of investment in physical and human capital is assessed. This improves our understanding of the economic implications of the demographic dividend and particularly the “second demographic dividend”

COVERT RESISTANCE AGAINST ALGORITHMIC CONTROL ON ONLINE LABOR PLATFORMS – A SYSTEMATIC LITERATURE REVIEW

Online labor platforms (OLP) such as Uber or Upwork heavily rely on algorithms instead of human managers to control workers’ behavior. While algorithmic control (AC) allows platform providers to control their workers efficiently, it is often perceived by workers as a tighter control (compared to human-based control) which increases their motivation to resist. Especially covert resistance (i.e., workers’ hard-to-observe oppositional actions) provides essential insights into how workers deal with AC that affect platforms’ longevity. In this study, we conducted a systematic literature review to develop a theoretical framework showing how and why workers perform covert resistance against AC. Further, our analysis reveals the enabling role of sensemaking for diverse forms of covert resistance. Overall, our study expands the literature on AC by shedding light on the formation of workers’ covert resistance. Therefore, we offer platform providers and policymakers crucial insights to create fairer working environments for workers under AC

Scanning Capacitance Spectroscopy on n\u3csup\u3e+\u3c/sup\u3e-p Asymmetrical Junctions in Multicrystalline Si Solar Cells

We report on a scanning capacitance spectroscopy (SCS) study on the n+-p junction of multicrystalline silicon solar cells. We found that the spectra taken at space intervals of ∼10 nm exhibit characteristic features that depend strongly on the location relative to the junction. The capacitance-voltage spectra exhibit a local minimum capacitance value at the electrical junction, which allows the junction to be identified with ∼10-nm resolution. The spectra also show complicated transitions from the junction to the n-region with two local capacitance minima on the capacitance-voltage curves; similar spectra to that have not been previously reported in the literature. These distinctive spectra are due to uneven carrier-flow from both the n- and p-sides. Our results contribute significantly to the SCS study on asymmetrical junctions

Should we change formula for a formula-fed infant with persistent spitting up, but with adequate weight gain?

We found no controlled trials evaluating the efficacy of changing formulas in the management of uncomplicated regurgitation. However, the evidence suggests that no benefit can be expected from changing formulas, including the discontinuation of iron-fortified formulas. Additionally, changing formulas leads many mothers to believe that their child has a disease or illness. Although controlled trials of infants with gastroesophageal reflux disease (GERD) show that formula thickening (eg, with rice cereal) decreases spitting-up, and expert consensus panels recommend formula thickening (along with parental reassurance) as first-line therapy in the management of uncomplicated regurgitaion, one could question whether these outcomes in infants with GERD would hold for infants with uncomplicated regurgitation. Flat-prone positioning and avoiding the seated position is beneficial in infants with GERD, but the association of prone positioning with sudden infant death syndrome limits this intervention. (Grade of recommendation: D, based on a synthesis of information from controlled trials performed in other patient populations, retrospective surveys, physiologic evidence, and consensus expert opinion.

Liquidity and Market Crashes

In this paper, we develop an equilibrium model for stock market liquidity and its impact on asset prices when constant market presence is costly. We show that even when agents' trading needs are perfectly matched, costly market presence prevents them from synchronizing their trades and hence gives rise to endogenous order imbalances and the need for liquidity. Moreover, the endogenous liquidity need, when it occurs, is characterized by excessive selling of significant magnitudes. Such liquidity-driven selling leads to market crashes in the absence of any aggregate shocks. Finally, we show that illiquidity in the market leads to high expected returns, negative and asymmetric return serial correlation, and a positive relation between trading volume and future returns. We also propose new measures of liquidity based on its asymmetric impact on prices and demonstrate a negative relation between these measures and expected stock returns.

Market Liquidity, Asset Prices and Welfare

This paper presents an equilibrium model for the demand and supply of liquidity and its impact on asset prices and welfare. We show that when constant market presence is costly, purely idiosyncratic shocks lead to endogenous demand of liquidity and large price deviations from fundamentals. Moreover, market forces fail to lead to efficient supply of liquidity, which calls for potential policy interventions. However, we demonstrate that different policy tools can yield different efficiency consequences. For example, lowering the cost of supplying liquidity on the spot (e.g., through direct injection of liquidity or relaxation of ex post margin constraints) can decrease welfare while forcing more liquidity supply (e.g., through coordination of market participants) can improve welfare.