Application of kinetic damping in dynamic material point method for static problems

Material point method (MPM) is widely used in geotechnical engineering, owing to its powerful capability of modelling large deformation problems. But the static equilibrium problems involving very large deformation and material non-linearity can be difficult to solve using the quasi-static MPM, because of numerical difficulties with convergence in iterative procedure. An alternative method is the dynamic relaxation (DR) method, which converts the static problem to a dynamic one by considering the virtual masses and artificial damping. This paper presents a method to solve static problems using dynamic MPM with DR technique. An energy ratio and a force ratio are defined to recognize the static equilibrium state from dynamic process first. Then the kinetic damping as an DR technique is introduced into the dynamic MPM for the first time. Finally, two numerical examples are presented to illustrate the convenience and efficiency of the kinetic damping in dynamic MPM for static problems

Comparison of three airborne laser bathymetry data sets for monitoring the German Baltic Sea Coast

Airborne laser bathymetry (ALB) can be used for hydrographic surveying with relative high resolution in shallow water. In this paper, we examine the applicability of this technique based on three flight campaigns. These were conducted between 2012 and 2014 close to the island of Poel in the German Baltic Sea. The first data set was acquired by a Riegl VQ-820-G sensor in November 2012. The second and third data sets were acquired by a Chiroptera sensor of Airborne Hydrography AB in September 2013 and May 2014, respectively. We examine the 3D points classified as seabed under different conditions during data acquisition, e.g. the turbidity level of the water and the flight altitude. The analysis comprises the point distribution, point density, and the area coverage in several depth levels. In addition, we determine the vertical accuracy of the 3D seabed points by computing differences to echo sounding data. Finally, the results of the three flight campaigns are compared to each other and analyzed with respect to the different conditions during data acquisition. For each campaign only small differences in elevation between the laser and the echo sounding data set are observed. The ALB results satisfy the requirements of IHO Standards for Hydrographic Surveys (S-44) Order 1b for several depth intervals. © 2015 SPIE

Angularity in Higgs boson decays via H→gg\boldsymbol{H\to gg} at NNLL′^{'} accuracy

We present improved predictions of a class of event-shape distributions called angularity for a contribution from an effective operator $H\to gg$ in Higgs hadronic decay that suffers from large perturbative uncertainties. In the frame of Soft-Collinear Effective Theory, logarithmic terms of the distribution are resummed at NNLL$^{'}$ accuracy, for which 2-loop constant of gluon-jet function for angularity is independently determined by a fit to fixed-order distribution at NLO corresponding to ${\mathcal{O}}(\alpha_s^2)$ relative to the born rate. Our determination shows reasonable agreement with value in a thesis recently released. In the fit, we use an asymptotic form with a fractional power conjectured from recoil corrections at one-loop order and it improves the accuracy of determination in positive values of angularity parameter $a$. The resummed distribution is matched to the NLO fixed-order results to make our predictions valid at all angularity values. We also discuss the first moment and subtracted moment of angularity as a function of $a$ that allow to extract information on leading and subleading nonperturbative corrections associated with gluons.Comment: 33 pages, 12 figure

Unpacking How Decentralized Autonomous Organizations (DAOs) Work in Practice

Decentralized Autonomous Organizations (DAOs) have emerged as a novel way to coordinate a group of (pseudonymous) entities towards a shared vision (e.g., promoting sustainability), utilizing self-executing smart contracts on blockchains to support decentralized governance and decision-making. In just a few years, over 4,000 DAOs have been launched in various domains, such as investment, education, health, and research. Despite such rapid growth and diversity, it is unclear how these DAOs actually work in practice and to what extent they are effective in achieving their goals. Given this, we aim to unpack how (well) DAOs work in practice. We conducted an in-depth analysis of a diverse set of 10 DAOs of various categories and smart contracts, leveraging on-chain (e.g., voting results) and off-chain data (e.g., community discussions) as well as our interviews with DAO organizers/members. Specifically, we defined metrics to characterize key aspects of DAOs, such as the degrees of decentralization and autonomy. We observed CompoundDAO, AssangeDAO, Bankless, and Krausehouse having poor decentralization in voting, while decentralization has improved over time for one-person-one-vote DAOs (e.g., Proof of Humanity). Moreover, the degree of autonomy varies among DAOs, with some (e.g., Compound and Krausehouse) relying more on third parties than others. Lastly, we offer a set of design implications for future DAO systems based on our findings