Applying Projection‐Based Methods to the Asymmetric Traffic Assignment Problem

This article examines the application of a path‐based algorithm to the static and fixed demand asymmetric traffic assignment problem. The algorithm is of the simplicial decomposition type and it solves the equilibration or master problem step by means of five existing projection methods for variational inequality problems to evaluate their performance on real traffic networks. The projection methods evaluated are: (1) a cost approximation‐based method for minimizing the Fukushima's gap function, (2) the modified descent method of Zhu and Marcotte ( 1988 ), (3) the double projection method of Khobotov ( 1987 ) and three of its recently developed variants (Nadezhkina and Takahashi, 2006 ; Wang et al., 2010 ; and He et al., 2012); (4) the method of Solodov and Svaiter ( 1999 ); and (5) the method of Solodov and Tseng ( 1996 ). These projection methods do not require evaluation of the Jacobians of the path cost functions. The source for asymmetries are link costs with interactions, as in the case of priority ruled junctions. The path‐based algorithm has been computationally tested using the previous projection methods on three medium to large networks under different levels of congestion and the computational results are presented and discussed. Comparisons are also made with the basic projection algorithm for the fixed demand asymmetric traffic assignment problem. Despite the lack of monotonicity properties of the test problems, the only method that failed to converge under heavy congestion levels was the basic projection algorithm. The fastest convergence was obtained in all cases solving the master problem step using the method of He et al. (2012), which is a variant of Khobotov's method.     

Twin-mass accelerometer optimization to reduce the package stresses

The geometry optimization of a piezoresistive Twin-mass accelerometer is presented. The Twin-mass design is the most sensitive design to the stresses of the package compared to the Cantilever beam and the Quad-beam designs. Finite element simulations are carried out to improve the geometry of the Twin-mass design. Substitution of the perpendicular external beams by lateral external beams reduces the effects of the stresses of the package by a factor of more than 40. Moreover, the sensitivity and the figure of merit of the device can be easily increased.     

Fatigue load computation of wind turbine gearboxes by coupled finite element,multi‐body system and aerodynamic analysis

The main concern of the present publication is the computation of dynamic loads of wind turbine power trains, with particular emphasis on planetary gearbox loads. The applied mathematical approach relies on a non‐linear finite element method, which is extended by multi‐body system functionalities, and aerodynamics based on the blade element momentum theory. Copyright © 2007 John Wiley & Sons, Ltd.     

BER analysis of group-orthogonal multicarrier code-division multiplex systems

Group-orthogonal multi-carrier code division multiple access (GO-MC-CDMA) has recently been proposed as a promising technique for the uplink segment of wireless systems. In this paper we propose and analyze a related scheme, group-orthogonal multi-carrier code division multiplexing (GO-MC-CDM), suitable for the downlink segment of the future generation of wireless systems. The proposed system is shown to offer a similar bit error rate (BER) performance as the downlink version of GO-MC-CDMA at a fraction of its computational complexity. An analytical expression for the BER when using maximum likelihood (ML) detection is derived providing valuable insight into the parameters affecting the system performance and providing a basis for its optimization. Simulation results using parameters and (correlated) channel models aiming at the next generation of wireless systems are provided confirming the analytically derived results.     

Pre‐reservation of Resources and Controlled Loops for Contention Resolution in OBS Networks

A new scheme to alleviate contention in optical burst switching networks is proposed. It consists of preventively reserving resources in a node, to be used if resources are busy on the next hop node. The burst is sent back to the preceding node and then resent forward. Simulations are carried out to assess the feasibility of the proposed scheme. Its performance is compared with that of contention resolution based on deflection routing.     

Non‐resonant Element in Slotted Ground Plane for Multiband Antenna Operation

New ways of achieving small, multiband, multifunctional, and standard solutions for mobile handset antennas are demanded in the current wireless market. A non‐resonant element of , a matching network, and a slotted ground plane are proposed to satisfy mobile market demands that require multiband operation and small antenna solutions. The main advantage of the proposed design is that with only one non‐resonant element of considerably small size (0.015λ, 900 MHz), the handset is capable of providing operation at mobile bands.     

Fun and fear: The banalization of nuclear technologies through display

How do nuclear technologies become commonplace? How have the borders between the exceptional and the banal been drawn and redrawn over the last 70 years in order to make nuclear energy part of everyday life? This special issue analyzes the role of fun and display, broadly construed, in shaping the cultural representation and the material circulation (or non‐circulation) of nuclear technologies. Four case studies, covering the United States, Great Britain, Portugal, Spain, and Ukraine from the 1950s to the 2000s, explore how specific forms of public display and playful practices of cultural production were used as means to banalize (or de‐banalize) nuclear energy. This introduction addresses the main theoretical and historiographical signposts of the special issue and outlines the different ways in which the articles explore them.