For a long time, the bilevel programming problem has essentially been considered as a special case of mathematical programs with equilibrium constraints (MPECs), in particular when the so-called KKT reformulation is in question. Recently though, this widespread believe was shown to be false in general. In this paper, other aspects of the difference between both problems are revealed as we consi...

This paper addresses two second-best toll pricing problems, one with fixed and the other with elastic travel demands, as mathematical programs with equilibrium constraints. Several equivalent nonlinear programming formulations for the two problems are discussed. One formulation leads to properties that are of interest to transportation economists. Another produces an algorithm that is capable o...

This paper introduces six ways for handling a chain of lexicographic ordering constraint between the origins of identical orthotopes (e.g., rectangles, boxes, hyper-rectangles) subject to the fact that they should not pairwise overlap. While the first two ways deal with the integration of a chain of lexicographic ordering constraint within a generic geometric constraint kernel, the four latter ...

Symmetry is an important feature of many constraint programs. We show that any problem symmetry acting on a set of symmetry breaking constraints can be used to break symmetry. Different symmetries pick out different solutions in each symmetry class. This simple but powerful idea can be used in a number of different ways. We describe one application within model restarts, a search technique desi...

Microblog retrieval enables users to access relevant information from the huge number of tweets posted on social media. Since tweets are different from traditional documents, existing IR models might not be the optimal choice for this problem. Tie-breaking has been recently proposed as a new way of combining multiple retrieval signals. In this paper, we focus on studying the potential of this a...

The jaw plays a significant role in speech production. This work introduces a muscle activated dynamic jaw model that will be connected in the future to the 3D tongue model already developed by our group. The bone structure of the jaw, extracted from CT Images, is represented as a biomechanical model using quadrilateral shell elements. Opener and closer muscles are represented as line-segmented...

We consider a problem of managing a system of spatially distributed markets under capacity and balance constraints and show that solutions of a variational inequality enjoy auction principle properties implicitly. This enables us to develop efficient tools both for derivation of existence and uniqueness results and for creation of solution methods.

The platform integration study on hospital management information system with common interface had the data exchange and sharing on several information platform come true. The external study is to apply the results to bigger score and operating surroundings. The study about Computer-Based Patient Record (CPR) on Health Level Seven (HL7) combing the middleware is to achieve the uniform data and ...

natural frequency is one of the parameters that represent useful information about the dynamic behavior of structures. controlling this parameter can decrease the probability of damage under dynamic loading. weight optimization on layout and sizing with frequency constraints is a well known problem because of its highly non-linear behavior. improved ray optimization (iro) algorithm is utilized ...