Efficient Online Surface Correction for Real-time Large-Scale 3D Reconstruction

State-of-the-art methods for large-scale 3D reconstruction from RGB-D sensors usually reduce drift in camera tracking by globally optimizing the estimated camera poses in real-time without simultaneously updating the reconstructed surface on pose changes. We propose an efficient on-the-fly surface correction method for globally consistent dense 3D reconstruction of large-scale scenes. Our approach uses a dense Visual RGB-D SLAM system that estimates the camera motion in real-time on a CPU and refines it in a global pose graph optimization. Consecutive RGB-D frames are locally fused into keyframes, which are incorporated into a sparse voxel hashed Signed Distance Field (SDF) on the GPU. On pose graph updates, the SDF volume is corrected on-the-fly using a novel keyframe re-integration strategy with reduced GPU-host streaming. We demonstrate in an extensive quantitative evaluation that our method is up to 93% more runtime efficient compared to the state-of-the-art and requires significantly less memory, with only negligible loss of surface quality. Overall, our system requires only a single GPU and allows for real-time surface correction of large environments.Comment: British Machine Vision Conference (BMVC), London, September 201

Fundamentals, Misvaluation, and Investment. The Real Story

Is real investment fully determined by fundamentals or is it sometimes affected by stockmarket misvaluation? We introduce three new tests that: measure the reaction of investment to sales shocks for firms that may be overvalued; use Fama-MacBeth regressions to determine whether "overinvestment" affects subsequent returns; and analyze the time path of the marginal product of capital in reaction to fundamental and misvaluation shocks. Besides these qualitative tests, we introduce a measure of misvaluation into standard investment equations to estimate the quantitative effect of misvaluation on investment. Overall, the evidence suggests that both fundamental and misvaluation shocks affect investment.Investment, Stock market, Fundamentals, Misvaluation, Bubbles, Real effects of financial markets

Do Bubbles Lead to Overinvestment?: A Revealed Preference Approach

Many economists believe that the stock market plays an important role in efficiently allocating capital to its most productive uses. This standard story of the stock market was called into question by events in the late 1990s, when some observers believed that stock market overvaluation – or a bubble - led to overinvestment. Both the standard and overinvestment stories involve discount rates and, to differentiate between the two stories, this paper examines the discount rates used by firms in making their investment decisions.We use a revealed preference approach that relies on the pattern of investment spending – combined with investment theory – to estimate the discount rates used by managers. The standard story predicts that firms with high stock prices and good investment opportunities should have discount rates that do not differ systematically from the risk-adjusted market rate. The overinvestment story predicts that firms with high stock prices and poor investment opportunities should have discount rates consistently below the market rate.Based on a panel dataset of over 50,000 firm-year observations, we find support for both stories. The behavior of high stock price firms with good measured investment opportunities is best described by the standard story, while the overinvestment story provides the most appropriate interpretation of the behavior of high stock price firms with poor investment opportunities. Firms in this latter category accumulate between 15.1% and 45.2% too much capital. These estimates suggest that, even before they burst, bubbles adversely affect economic activity by misallocating capital.bubbles, investment, stock markets, real effects of financial markets, capital formation

Fundamentals, Misvaluation, and Investment: The Real Story

Is real investment fully determined by fundamentals or is it sometimes affected by stock market misvaluation? We introduce three new tests that: measure the reaction of investment to sales shocks for firms that may be overvalued; use Fama-MacBeth regressions to determine whether "overinvestment" affects subsequent returns; and analyze the time path of the marginal product of capital in reaction to fundamental and misvaluation shocks. Besides these qualitative tests, we introduce a measure of misvaluation into standard investment equations to estimate the quantitative effect of misvaluation on investment. Overall, the evidence suggests that both fundamental and misvaluation shocks affect investment.investment, stock market, fundamentals, misvaluation, bubbles, real effects of financial markets

A Revealed Preference Approach. To Understanding Corporate Governance Problems: Evidence From Canada

Empire-building by managers implies that they use a lower effective discount rate in making investment decisions. We use actual investment decisions to measure the gap between the manager’s effective discount rate and the market rate. Our empirical work is based on panel data for 193 Canadian firms. Distinctive institutional features, such as interrelated groups of Canadian firms and concentrated share ownership, allow us to quantify the sensitivity of effective discount rates and governance problems to these institutional control mechanisms. For the firms most likely to be affected by the agency problems highlighted by Jensen (1986), estimated discount rates are 350-400 basis points less than the market rate, supporting the Free Cash Flow view that unresolved corporate governance problems distort firm behavior. Firms in our sample that face Free Cash Flow problems have a stock of fixed capital approximately 7% to 22% higher than would prevail under value maximizing behavior.Corporate governance, Business investment, Discount rates

The Irreversibility Premium

When investment is irreversible, theory suggests that firms will be “reluctant to invest.” This reluctance creates a wedge between the discount rate guiding investment decisions and the standard Jorgensonian user cost (adjusted for risk). We use the intertemporal tradeoff between the benefits and costs of changing the capital stock to estimate this wedge, which we label the irreversibility premium. Estimates are based on panel data for the period 1980-2001. The large dataset allows us to estimate the effects of limited resale markets, low depreciation rates, high uncertainty, and negative industry-wide shocks on the irreversibility premium. Our estimates provide a readily interpretable measure of the importance of irreversibility and document that the irreversibility premium is both economically and statistically significant.irreversibility, investment, non-convex adjustment costs

How do the grains slide in fine-grained zirconia polycrystals at high temperature?

Degradation of mechanical properties of zirconia polycrystals is hardly discussed in terms of solution-precipitation grain-boundary sliding due to experimental controversies over imaging of intergranular amorphous phases at high and room temperatures. Here, the authors applied the techniques of mechanical spectroscopy and transmission electron microscopy (TEM) to shed light on the amorphization of grain interfaces at high temperature where the interface-reaction determines the behaviour of fine-grained zirconia polycrystals. They present mechanical spectroscopy results, which yield evidences of an intergranular amorphous phase in silica doped and high-purity zirconia at high temperature. Quenching of zirconia polycrystals reveals an intergranular amorphous phase on TEM images at room temperature.Comment: 12 pages, 3 figure

Using a Functional Language Approach to Engage High School English Language Learners in Academic Language Arts Content

The research question addressed in this capstone project was; how can a curriculum, rooted in the experiential metafunction of functional language analysis, be developed to help secondary English language learners gain academic language needed in a language arts classroom? It looks at the struggle high school ELLs face because of the academic language used in content classes. It also looks at the components of functional language analysis and how they can be used to teach the academic language needed for student success. The author utilized the work of Christie, F. (2012), Fang, Z., & Schleppegrell, M. J. (2008), and Martin, J. R., & Rose, D. (2007) to create a unit curriculum focused on the experiential meaning of a short novel. The curriculum instructs learners on how to identify the process, participant, and circumstance and analyze how the choice of language affects the meaning. The author concludes that implementing a functional language approach is beneficial to student comprehension of academic language and can be used in all content areas