the main objective of this article is to optimize the walking pattern of a 2d humanoid robot with heel-off and toe-off motions in order to minimize the energy consumption and maximize the stability margin. to this end, at first, a gait planning method is introduced based on the ankle and hip joint position trajectories. then, using these trajectories and the inverse kinematics, the position tra...

In this paper, we apply the homotopy perturbation transform method (HPTM) to obtain the solution of linear and nonlinear Schrödinger equations. The HPTM is a combined form of the Laplace transform method with the homotopy perturbation method. This method finds the solution without any discretization or restrictive assumptions and avoids the round-off errors. The fact that this technique solves ...

Computation of principal angles between subspaces is important in many applications, e.g., in statistics and information retrieval. In statistics, the angles are closely related to measures of dependency and covariance of random variables. When applied to column-spaces of matrices, the principal angles describe canonical correlations of a matrix pair. We highlight that all popular software code...

We describe a new method of computing functions of highly non-normal matrices, by using the concept of approximate diagonalization. We formulate a conjecture about its efficiency, and provide both theoretical and numerical evidence in support of the conjecture. We apply the method to compute arbitrary real powers of highly non-normal matrices. 1. Introduction. Let A be a non-normal n × n matrix...

In this paper, we built an agent-based model to integrate and synthesize social science theories to inform online community design. As an example, we use the model to examine how various styles of moderating online conversations affect community performance. We compared three styles of moderation – no moderation, in which all members are exposed to all messages; community-level moderation, in w...

An emerging trend in classrooms is the use of networked visual argumentation tools that allow students to discuss, debate, and argue with one another in a synchronous fashion about topics presented by a teacher. These tools are aimed at teaching students how to discuss and argue, important skills not often taught in traditional classrooms. But how do teachers support students during these e-dis...

In May 2011, we embarked on an ambitious course – in 3 weeks: clear out a small, soon to be demolished, research datacenter containing 5 dozen research systems spanning 5 research groups and, along with a new faculty member’s systems located off-site, move it all into another space suffering from 18 years of accumulated computer systems research history. We made it happen, but only after intens...