Statistical Modeling and Worst-Case Design Parameters

Author(s):  
Narain Arora
2003 ◽  
pp. 563-566 ◽  
Author(s):  
A. J. Strojwas ◽  
S. R. Nassif ◽  
S. W. Director

Author(s):  
Ana B. Rodriguez-Gonzalez ◽  
Luis M. Lopez-Ramos ◽  
Antonio G. Marques ◽  
Javier Ramos ◽  
Antonio J. Caamano

Author(s):  
Zhenyu Qi ◽  
Yan Zhang ◽  
Mircea Stan

Corner-based design and verification are based on worst-case analysis, thus introducing over-pessimism and large area and power overhead and leading to unnecessary energy consumption. Typical case-based design and verification maximize energy efficiency through design margins reduction and adaptive computation, thus helping achieve sustainable computing. Dynamically adapting to manufacturing, environmental, and usage variations is the key to shaving unnecessary design margins, which requires on-chip modules that can sense and configure design parameters both globally and locally to maximize computation efficiency, and maintain this efficiency over the lifetime of the system. This chapter presents an adaptive threshold compensation scheme using a transimpedance amplifier and adaptive body biasing to overcome the effects of temperature variation, reliability degradation, and process variation. The effectiveness and versatility of the scheme are demonstrated with two example applications, one as a temperature aware design to maintain IONto IOFFcurrent ratio, the other as a reliability sensor for NBTI (Negative Bias Temperature Instability).


Author(s):  
L-I Wu ◽  
W-T Chang

This paper presents an analytical method for analysing the mechanical errors of disc cam mechanisms. With the aid of parametric expressions of the cam profile and by employing the concept of equivalent linkage, the error of the follower motion that is due to the variation in each design parameter can be determined analytically. The resulting error equations do not really involve the location of the curvature centre of the cam profile, and thus locating the curvature centre of the cam profile is not essential. The method is validated through analysing a cam mechanism that has an invariant equivalent linkage, and thus an exact solution is available. Compared with the exact solutions, the predicted results have at least four-figure accuracy. For the roller follower cases, the pressure angle has most effect on the resulting error. Owing to the counteraction of the shift angle, the resulting error due to the radial dimension error of the cam profile has relatively smaller variation. In the worst case, owing to the combined effects of various design parameters, the accuracy of the follower motion may degrade considerably. The acceleration error functions have a sudden change at the ends of the motion.


Author(s):  
Kenneth C. Walls ◽  
David L. Littlefield ◽  
David E. Lambert

In order to make the process of fragmentation of warhead cases more systematic, we have developed a procedure that makes use of nonlinear optimization to derive optimal values for case design parameters subject to various design constraints. A framework has been developed that makes use of the optimization software package LS-OPT driving the hydrocode CTH (CTH is developed and maintained at Sandia National Laboratories, LS-OPT is commercially available from Livermore Software Technology Corp.). CTH was used to model the explosive detonation and determine the resultant kinetic energy delivered to the case by the energetic material. As an example of application of the framework, a test problem was run using a case configuration consisting alternating titanium alloy and polymer layers.


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