Mass-spring systems are of special interest for soft tissue modeling in surgical simulation due to their ease of implementation and real-time behavior. However, the parameter identification (masses, spring constants, mesh topology) still remains a challenge. In previous work, we proposed an approach based on the training of mass-spring systems according to known reference models. Our initial fo...

This paper discusses the stability of 2D frictionless grasps and combining stability of frictional and frictionless grasps from the viewpoint of potential energy method. In many works related to the frictionless grasp, each finger is replaced by one directional virtual spring along the normal at the contact point. However, this condition is not accurate, because the frictionless condition does ...

In this paper, a procedural method for the visualization of knitted and woven fabrics is presented. The proposed method is compatible with a mass-spring model and makes use of the regular warp–weft structure of the cloth. The visualization parameters for the loops and threads are easily mapped to the animated mass-spring model. The simulation idea underlying both knitted and woven fabrics is si...

In this work, by replacing the traditional solid spokes with colloidal spokes, a vehicle wheel with a built-in suspension structure is proposed. Following the background and description of the wheel system, firstly, a vibration model of the wheel equipped with colloidal spokes is proposed, and based on such model the equivalent damping coefficients and spring constants are identified. Then, a m...

The Yoneda Lemma tells us that the Hom bifunctor is “non-degenerate” in a similar way. (a) For each object X ∈ C verify that hX := HomC(X,−) defines a functor C → Set. (b) Given two objects X,Y ∈ C state what it means to have hX ≈ hY as functors. (c) Given two objects X,Y ∈ C and an isomorphism of functors hX ≈ hY , prove that we have an isomorphism of objects X ≈ Y . [Hint: Let Φ : hX ∼ −→ hY ...

Protocol A Magnetic Particle-Based Method for Purifying PCR Products from Solution Craig Smith, Paul Otto, Rex Bitner, and Gary Shiels This protocol was adapted from "DNA Purification," contributed by Craig Smith, Paul Otto, Rex Bitner, and Gary Shiels in Chapter 9, PCR Primer, 2nd edition (eds. Dieffenbach and Dveksler). Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, USA, 2...

Bipedal robots are diicult to analyze mathematically. However, successful control strategies can be discovered using simple physical intuition and can be described in simple terms. Five things have to happen for a planar bipedal robot to walk. Height has to be stabilized. Pitch has to be stabilized. Speed has to be stabilized. The swing leg has to move so that the feet are in locations which al...

This article describes a mechanical vertical attenuation system capable to provide large attenuation factors above 1Hz. This system is derived from, and improves, the passive Geometric Anti-Spring seismic attenuation filters minimizing their vertical resonant frequency by means of a tunable electromagnetic spring mounted in parallel with the main spring. The tunable spring is also used to compe...