Improvements in Dynamic Characteristics of Automobile Suspension Systems Part 1. Two-Mass Systems

In a previous paper, [3] the random vibrations of simple linear models of automobile suspension were solved with respect to seat elasticity and human sensitivity to vibrations. The present study uses more realistic linear models taking into account the unsprung mass.

Two configurations of masses are investigated: a two-mass system consisting of a sprung mass and an unsprung mass, and a three-mass system having an additional mass which acts as a vibration absorber. The gain in comfort obtained by lowering the natural frequency of the sprung mass is calculated for various two-mass and three-mass models along with other characteristics such as the dynamic tyre load, spring and damper forces and relative motion of the masses.     

The design of liner shipping serives: the problem of feeder services versus multi-port-calls

In this paper, the authors outline the structure of liner shipping systems with special emphasis on the question of whether feeder services are superior in economic terms to the more traditional and commonly-used multi-port-calling system. They describe the theoretical advantages of the former over the latter, and develop a model by which the optimal conditions both operate in may be determined. This model is then applied to a real situation to ascertain whether the theory works in practice. They conclude that the shuuttle/feeder system is worthwhile only in exceptional circumstances when specific route characteristics—low trade density; hinterland generated cargo; inland position of port; and heavy congestion—coexist. Despite the expense of multi-port-calling, it remains the most practical solution to the thin trade problem.     

Seabed scene simulation and its realization in extending Vega

Realistic simulation of underwater scene is always difficult because of the special and complex vision effects in underwater space. Seabed is an important part of underwater environment. This paper describes the methods for seabed scene simulation based on OpenGL. It includes construction of fluetuant terrain based on the random sinusoidal algorithm, simulation of seabed flicker effect by means of circular texture mapping and generation of turbidity effect by using fog techniques. For the application based on the leading high level 3D development environment-Vega, underwater scene simulation is still a difficulty since there is no module for it. Based on the analysis of Vega software and the research on seabed scene simulation methods, a Vega extending module named “Underwater Space” was created through developing module class and extending lynx interface. The module class was designed through developing DLL written in C . The Lynx was extended through developing keyword configure file, GUI configure file and lynx plug-in DLL. The problem that Vega can‘t simulate underwater space, is elementarily resolved. The results show that this module is efficient, easy using, and the seabed scene images am vivid.     

Roll Dynamics of Commercial Vehicles

An analytical model is developed here for studying the roll dynamics of commercial vehicles. Large displacements and rotations are accounted for in this nonlinear model so that it can be used for the study of roll dynamics well beyond the limits of wheel lift-off. The model is used to illustrate some of the dynamic phenomena in vehicle rollover, especially the interactive coupling between the roll and the vertical modes of motion. The influence of suspension backlash on rollover resistance is demonstrated, and the phenomenon of roll motion resonance is illustrated to suggest new means for evaluating vehicle rollover sensitivity.     

Identity-based threshold decryption on access structure

For the applied limitation of the existing threshold decryption schemes based on the (t, n) structure, an identity-based threshold decryption scheme which can be applied on the access structure is proposed through designing a special distribution algorithm of the private key shares. The generation and distribution of private key shares, the encryption, the decryption and the combination are introduced in detail. The validity and security of the scheme are proved and analyzed. Comparisons with the existing schemes show that the proposed scheme is more flexible.     

Tool sequence optimization based on three logical modes of robot control via CPLEX optimization

Cluster tools have advantages of shorter cycle times, faster process development, and better yield for less contamination. The sequence of dual-arm cluster tools is a complex logistics process during the semiconductor production. Efficient use of cluster tools is naturally very significant to competitive fab operations. Generating an optimized sequence in a computationally efficient manner and assessing the quality of the requirements to improve the fab production are the key factors for semiconductor manufacturing productivity. The Petri net modeling is introduced to minimize the makespan of the process for the three different logical modes and select a better mode after comparing the makespan among the three logical modes. The tool sequence optimization problem is formulated as optimization firing transition sequences based on the Petri net and then the formulation is converted to be linearly solved by the branch-and-cut method in the standard commercial solver CPLEX. Special methods for the linear conversion are highlighted. Due to the limited calculation time requirement for the real production and the large scale of the problem, special methods for the efficiency tuning are applied according to the characteristics of the problem. Numerical testing is supported by one of the most advanced semiconductor enterprises and the computational results show significant improvement compared with the traditional manual sequence results.     

Poisson noise removal based on nonlocal total variation with Euler’s elastica pre-processing

An enhancement-based Poisson denoising method for photon-limited images is presented. The noisy image is firstly pre-processed for enhancing incomplete object information, and then it is denoised while preserving the restored structural details. A variational regularization model based on Euler’s elastica (EE) is proposed for image enhancement pre-processing. A nonlocal total variation (NLTV) regularization model is then employed in the second stage of image denoising. The above two optimization problems are solved by the alternating direction method of multipliers (ADMM). For Poissonian images with low image peak values, experiments demonstrate the validity and efficiency of the proposed method for both restoring geometric structure and removing noise.