Too slow acceleration of cars downstream a traffic jam can have a dramatic impact on the jam's lifetime and cause much delay for motorists behind. It has been observed that cars leaving a traffic jam reach cruise speed much later than predicted by car-following models and space headway to the car ahead tends to be long. Using traffic flow simulation we have quantified the delays caused by such driving behavior. We also review some speculations that explain the driving style and possible remedies through vehicle intelligence.

The emerged computer-aided industrial design (CAID) systems gain increasing popularity among industrial designers. Despite the large number of deformation techniques already implemented in commercial systems or described in the literature, these techniques still lack in providing designers with meaningful shape deformations tools. In this work, we address this issue through the allocation of meaningful parameters and constraints to support specific shape deformations. Therefore, we introduce the concept of a shape context, which incorporates specific parameters, constraints and shape variation procedures that helps designers to quicker reach a desired shape. A shape design tool, MAPTool, has been developed based on the shape context concept. MAPTool helps designers to reach different shapes using one shape deformation through the alteration of its two meaningful parameters. Two product models developed using MAPTool are shown. Finally, we conclude that providing designers with meaningful parameters based on the shape context proves to be very promising.

Finding effective and efficient methods to fit and manipulate an existing freeform shape is one of the state-of-the-art topics in computer-aided design. Although general approaches give satisfied results, the computation time and the complexity often prevent their further developments in more complex cases especially in reusing an existing design. In this paper, for a better control of existing freeform shapes, feature based deformable freeform templates are introduced as the bridge between user actions and the existing freeform shapes. By the advantage of the small number of intrinsic parameters, existing freeform shapes are quickly approximated by the deformable templates. Based on the extendable concept, those deformable templates are further developed to match complex freeform shapes. With the distance and the projection mapping, the original shape and the approximated template are associated. Thus, further shape manipulations can be conducted effectively using the shape intrinsic parameters. Numerical experiments are conducted in order to verify the proposed algorithms. It is also described how the matching technique can be applied in computer graphics and computer-aided design applications.

Presents an interface between a deformable body mechanics model and a rigid body mechanics model. What is novel with our approach is that the physical representation in both the models is the same, which ensures behavioral correctness and allows great flexibility. We use a mass-spring representation extended with the concept of volume, and thus contact and collision. All physical interaction occurs between the mass elements only, and thus there is no need for explicit handling of rigid-deformable or rigid-rigid body interaction. This also means that bodies can be partially rigid and partially deformable. It is also possible to change whether part of a body should be rigid or not dynamically. We present a demonstration example, and also possible applications in conceptual design engineering, geometric modeling, as well as computer animation.

Freeform features can be regarded as key elements of shape modeling. Commonly, features are defined, controlled and computed using parameters. We propose a feature formulation strictly based on the parameterization, as a mapping from an arbitrary set to some domain of interest. This formalism accommodates many of the common representation forms and in addition allows: the uniform definition of freeform features; the analysis of feature properties, such as their spatial coverage, differentiability, uniqueness, overlap; and the comparison of alternative parameterizations for a given type of feature, regarding user control and computation. We have investigated in detail two feature types, the ridge and the hole. The proposed parameterizations indeed provide both interactive control and automatic feature extraction, are the key functions of a flexible forward/backward design support tool. Numerical results of the freeform feature parameter extraction process are presented.