A GENERAL SOFTWARE TESTING MODEL INVOLVING OPERATIONAL PROFILES

2001 ◽  
Vol 15 (4) ◽  
pp. 519-533 ◽  
Author(s):  
Süleyman Özekici ◽  
I. Kuban Altinel ◽  
Ebru Angün

An operational profile describes, in a probabilistic way, how a software is utilized by its users. It makes the testing procedure more realistic and efficient. We consider a model where the software is tested sequentially in all of the operations that it is designed to perform. The stochastic and deterministic model parameters involving costs and failures all depend on the operations. In particular, the failure process generated by each fault is quite general and debugging is not necessarily perfect. Our aim is to find the optimal testing durations in all of the operations in order to minimize the total expected cost. This problem leads to an interesting nonlinear programming formulation that can be solved using well-known procedures in convex optimization.

1998 ◽  
Vol 120 (1) ◽  
pp. 63-73 ◽  
Author(s):  
K. N. Morman ◽  
E. Nikolaidis ◽  
J. Rakowska ◽  
S. Seth

A constitutive equation of the differential type is introduced to model the nonlinear viscoelastic response behavior of elastomeric bearings in large-scale system simulations for vibration assessment and component loads prediction. The model accounts for the nonlinear dependence of dynamic stiffness and damping on vibration amplitude commonly observed in the behavior of bearings made of particle-reinforced elastomers. A testing procedure for the identification of the model parameters from bearing component test data is described. The experimental and analytical results for predicting the behavior of four (4) different car bushings are presented. In an example application, the model is incorporated in an ADAMS simulation to study the dynamic behavior of a car rear suspension.


Author(s):  
A. J. Kakatsios ◽  
S. J. Tricamo

Abstract A novel integrated technique permitting the simultaneous optimization of kinematic and dynamic characteristics in the synthesis of spatial mechanisms is shown. The nonlinear programming formulation determines mechanism variables which simultaneously minimize the maximum values of bearing reactions, joint torques, driving torque, shaking moment, and shaking force while constraining the maximum kinematic structural error to a prescribed bound. The method is applied to the design of a path generating RRSS spatial mechanism with prescribed input link timing. Dynamic reactions in the mechanisms synthesized using the integrated technique were substantially reduced when compared to those of a mechanism synthesized to satisfy only the specified kinematic conditions.


Author(s):  
A. K. Dhingra ◽  
S. S. Rao

Abstract A new integrated approach to the design of high speed planar mechanisms is presented. The resulting nonlinear programming formulation combines both the kinematic and dynamic synthesis aspects of mechanism design. The multiobjective optimization techniques presented in this work facilitate the design of a linkage to meet several kinematic and dynamic design criteria. The method can be used for motion, path, and function generation problems. The nonlinear programming formulation also permits the imposition of constraints to eliminate solutions which possess undesirable kinematic and motion characteristics. To model the vague and imprecise information in the problem formulation, the tools of fuzzy set theory have been used. A method of solving the resulting fuzzy multiobjective problem using mathematical programming techniques is presented. The outlined procedure is expected to be useful in situations where doubt arises about the exactness of permissible values, degree of credibility, and correctness of statements and judgements.


2008 ◽  
Vol 130 (2) ◽  
Author(s):  
M. S. Allen ◽  
J. E. Massad ◽  
R. V. Field ◽  
C. W. Dyck

The dynamic response of a radio-frequency (RF) microelectromechanical system to a time-varying electrostatic force is optimized to enhance robustness to variations in material properties and geometry. The device functions as an electrical switch, where an applied voltage is used to close a circuit. The objective is to minimize the severity of the mechanical impact that occurs each time the switch closes because severe impacts have been found to significantly decrease the life of these switches. Previous works have demonstrated that a classical vibro-impact model, a single-degree-of-freedom oscillator subject to mechanical impact with a single rigid barrier, captures the relevant physics adequately. Certain model parameters are described as random variables to represent the significant unit-to-unit variability observed during fabrication and testing of a collection of nominally identical switches; these models for unit-to-unit variability are calibrated to available experimental data. Our objective is to design the shape and duration of the voltage waveform so that impact kinetic energy at switch closure is minimized for the collection of nominally identical switches, subject to design constraints. A voltage waveform designed using a deterministic model for the RF switch is found to perform poorly on the ensemble. An alternative waveform is generated using the proposed optimization procedure with a probabilistic model and is found to decrease the maximum impact velocity by a factor of 2 relative to the waveform designed deterministically. The methodology is also applied to evaluate a design change that reduces the impact velocity further and to predict the effect of fabrication process improvements.


2020 ◽  
Vol 12 (13) ◽  
pp. 5368
Author(s):  
Tomasz Owczarek ◽  
Mariusz Rogulski ◽  
Piotr O. Czechowski

The aim of the work is to demonstrate the possibility of building models to correct the results of measurements of particulate matter PM10 concentrations obtained using low-cost devices. Such devices apply the optical method to values comparable with those obtained using the reference gravimetric method. An additional goal is to show that the results corrected in this way can be used to carry out the procedure for testing equivalence of these methods. The study used generalized regression models (GRMs) to construct corrective functions. The constructed models were assessed using the coefficients of determination and the methodology of calculating the measurement uncertainty of the device. Measurement data from the two tested devices and the reference method were used to estimate model parameters. The measurement data were collected on a daily basis from 1 February to 30 June 2018 in Nowy Sącz. Regression allowed building multiple models with various functional forms and very promising statistical properties as well as good ability to describe the variability of reference measurements. These models also had very low values of measurement uncertainty. Of all the models constructed, a linear model using the original PM10 concentrations from the tested devices, air humidity, and wind speed was chosen as the most accurate and simplest model. Apart from the coefficient of determination, expanded relative uncertainty served as the measure of quality of the obtained model. Its small value, much lower than 25%, indicates that after correcting the results it is possible to carry out the equivalence testing procedure for the low-cost devices and confirm the equivalence of the tested method with the reference method.


2007 ◽  
Vol 54 (3) ◽  
pp. 346-355 ◽  
Author(s):  
Xiaoyue Jiang ◽  
Donglei Du ◽  
Thomas G. Ray

Author(s):  
Gregory Smith ◽  
Mike Blundell

This paper describes an efficient tyre test procedure that can be used to collect the data required to parameterise empirical tyre models used in the computer simulations of vehicle dynamics. The new GS2MF FreeRolling test procedure develops established methodologies, such as the time measurement procedure from the TIME project and the MICH2MF measurement protocol developed as alternatives to traditional square matrix testing. The new process is designed to reduce the number of expensive tyre tests without compromising the accuracy of the generated tyre model parameters. The process is demonstrated by a programme of tyre testing carried out using the Calspan TIRF tyre testing facility in the USA, and it is shown here how the GS2MF Flat-Trac® tyre test procedure can be used more efficiently to parameterise the pure lateral and self-aligning moment components for the well-known ‘magic formula’ tyre model. This is achieved using a ‘cruise’-type procedure which is more representative of conditions existing when driving a real vehicle. During the tests, a novel automated logic approach is also proposed to manage the temperature of the tyres. Finally, graph sweeps are introduced at the start and the end of the tests, allowing a judgement to be made as to the influence of the tyre wear on the data obtained throughout the tests. The development of accurate and representative tyre models remains a significant challenge as vehicle manufacturers target increased use of virtual prototypes and simulations. This work contributes to this challenge by improving the efficiency of the expensive testing process needed to parameterise the models.


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