Comments on “Viscoelastic studies of human subscapularis tendon: Relaxation test and a Wiechert model” by C. Machiraju, A.V. Phan, A.W. Pearsall, S. Madanagopal, Computer Methods and Programs in Biomedicine (2006)

Referring to the approach for determining the material parameters for a Wiechert model of the human subscapularis tendon proposed by Machiraju et al. [C. Machiraju, A.V. Phan, A.W. Pearsall, S. Madanagopal, Viscoelastic studies of a human subscapularis tendon: relaxation test and a Wiechert model, Computer Methods and Programs in Biomedicine (2006), doi:10.1016/j.cmpb.2006.05.004], some comments are made on the basis of the result of an alternative method that is capable of giving more reasonable values for the Wiechart model with the fitting discrepancies minimized by a multi-variable optimization strategy.     

Label relaxation using a linear mixture model

Abstract

A label relaxation method with a proportional estimation of mixed pixels (mixels) which is based on inversion problem solving techniques with a previously estimated proportion of neighbouring mixels is proposed. The method allows us to check the connectivity of separated road segments which arc observed frequently in the remote sensing satellite imagery. The experimental results with simulation data including observation noise show 73·5-98·8 per cent of improvement in terms of proportional estimation accuracy (RMS error), compared to the results from the previously proposed method with a generalized inverse matrix. Also the usefulness of the proposed label relaxation method with the proposed proportional estimation was confirmed for the investigation of the connectivity of the roads in the remote sensing satellite imagery.     

Using robots to model animals: a cricket test

The sensorimotor problems faced by animals and by robots have much in common, yet identifying this similarity has so far led to very few successful attempts to implement specific biological neural control structures on robots. One major limitation is that understanding of the biological mechanisms is insufficient for straightforward installation. However, using robots as a method of physically modeling animal systems can potentially contribute to our understanding of these mechanisms. This approach is employed in an investigation of phonotaxis (sound-seeking) in crickets. The process of building a robot forms the basis of a critical evaluation of the neuroethological evidence about the cricket, and generates an alternative hypothesis to explain this evidence. The explanatory power of this hypothesis is explored by testing and analyzing the behaviour of the robot that embodies it. The robot behaved like the cricket, competently and robustly finding its way to a specific sound source under a variety of conditions. It is argued that the methodology is more appropriate than symbolic simulation for the kinds of problems raised in the investigation of sensorimotor behaviour in animals and robots.     

Viscoelastic flow past a cylinder: drag coefficient

The channel flow of a viscoelastic fluid past a circular cylinder is simulated using a parallelized unstructured Finite Volume Method (FVM) [H.-S. Dou, N. Phan-Thien, J. Non-Newtonian Fluid Mech. 77 (1998) 21–51] under a distributed computing environment through the Parallel Virtual Machine (PVM) libraries. The numerical method is based on the SIMPLER (Semi-Implicit Method for Pressure-Linked Equations Revised) algorithm, using the simplified Phan-Thien/Tanner (PTT) and the Upper Convective Maxwell (UCM) constitutive models, with the Elastic Viscous Split Stress (EVSS) formulation. The parallelization of the program is implemented by a domain decomposition strategy and the PVM software. It is found that the both shear thinning and normal stress contribute to the drag reduction. With the PTT model, the drag reduction is mainly due to shear thinning. With the UCM model, it is primarily due to the normal stress effect.     

Contextual classification post-processing of LANDSAT data using a probabilistic relaxation model

A probabilistic relaxation model is used to improve maximum likelihood classifications of LANDSAT data of arid and urban areas in and around Ai Jahra, Kuwait. The problems of urban pixels, the role of compatibility coefficients and the iterations of the model are presented and discussed.     

Empirical studies of a safe regression test selection technique

Regression testing is an expensive testing procedure utilized to validate modified software. Regression test selection techniques attempt to reduce the cost of regression testing by selecting a subset of a program's existing test suite. Safe regression test selection techniques select subsets that, under certain well-defined conditions, exclude no tests (from the original test suite) that if executed would reveal faults in the modified software. Many regression test selection techniques, including several safe techniques, have been proposed, but few have been subjected to empirical validation. This paper reports empirical studies on a particular safe regression test selection technique, in which the technique is compared to the alternative regression testing strategy of running all tests. The results indicate that safe regression test selection can be cost-effective, but that its costs and benefits vary widely based on a number of factors. In particular, test suite design can significantly affect the effectiveness of test selection, and coverage-based test suites may provide test selection results superior to those provided by test suites that are not coverage-based     

Numerical analysis and computations of a high accuracy time relaxation fluid flow model

We present a numerical study based on continuous finite element analysis for a time relaxation regularization of Navier–Stokes equations. This regularization is based on filtering and deconvolution. We study the convergence of the regularized equations using a fully discretized filter and deconvolution algorithm. Velocity and pressure error estimates and the L ₂ Aubin–Nitsche lift technique are proved for the equilibrium problem, and this analysis is accompanied by the velocity error estimate for the time-dependent problem, too. Thus, optimal error estimates in L ₂ and H ¹ norms are derived and followed by their computational verification. Also, computational results of the vortex street are presented for the two-dimensional cylinder benchmark flow problem. Maximum drag and lift coefficients and difference in pressure between the front and back of the cylinder at the final time were investigated as well, showing that the time relaxation regularization can attain the benchmark values.     

Physicians' resistance toward healthcare information technology: a theoretical model and empirical test

This paper presents a theoretical model of physician resistance of healthcare information technology (HIT) usage by integrating the technology acceptance and resistance to change literatures, using a dual-factor model of technology usage. This model elaborates the interdependent and asymmetric effects of inhibiting usage perceptions, such as resistance, on HIT usage intentions relative to enabling perceptions, such as perceived usefulness and perceived ease of use. It also proposes perceived threat as a predictor of resistance, perceived compatibility as predicting perceived usefulness, and related knowledge as predicting perceived ease of use. The resulting model is empirically supported using a field survey of a computerized physician order entry system among 129 practicing physicians at a large acute-care hospital. Our study illustrates the importance of incorporating user resistance in technology usage studies in general and HIT usage studies in particular, grounds resistance research within extant theories of technology usage, and provides a preliminary model of resistance that can serve as the starting point for future research in this relatively unexplored yet potentially fertile area of research.     

TIM—a test improvement model

The software testing state of practice is not as good as it ought to be. To reduce the gap between the state of practice and the state of the art, improvement in software testing is necessary. Existing improvement models focus too little on, or lack important aspects of, software testing. Therefore a new model is required. This paper describes a test improvement model called TIM. The model functions as a guidebook for test improvement. It is mainly inspired by SEI's Capability Maturity Model and Gelperin's Testability Maturity Model. TIM introduces new perspectives to test improvement, with explicit focus on cost-effectiveness and risk management. The model addresses five ‘key areas’ of testing: organization, planning and tracking, test cases, testware and reviews. TIM also includes an assessment procedure. The model is continuously revised as knowledge is gained through research and experience of use. This paper presents results from three applications of TIM. © 1997 John Wiley & Sons, Ltd.     

Editorial: comfort and discomfort studies demonstrate the need for a new model

The term comfort is often seen relating to the marketing of products like chairs, cars, clothing, hand tools and even airplane tickets, while in the scientific literature, the term discomfort shows up often, since it is used in research. Few papers explain the concept of a localized comfort experience in relation to product use, although people use these products daily. Therefore, in this special issue, the concept of product comfort is studied further. In this editorial an overview of comfort models has been made, evaluated with the papers from the special issue and a new comfort/discomfort model is proposed to increase our understanding of the factors influencing comfort and discomfort experiences.     

Preventing problematic Internet use through video-based interventions: a theoretical model and empirical test

This study relies on the core ideas of the health belief model and suggests that short informational videos on Internet ‘addiction’ can be an effective means towards preventing problematic use of the Internet through their ability to drive changes in viewers’ attitudes towards reducing their Internet use. Building on the heuristic-systematic model of information processing viewpoint, it is further suggested that this attitude change is guided by the information the videos provide, as well as the surprise emotion they generate. To test this model, data were collected at three points in time from 223 participants who were exposed to one of two video interventions. Partial least-square analyses indicated that the videos were efficacious in improving viewers’ attitudes towards reducing their Internet use, after accounting for viewers’ preexisting attitudes, levels of Internet ‘addiction’, demographics and social desirability bias. Consistent with the heuristic-systematic model of information-processing perspective this effect was mobilised simultaneously through the information and surprise induced by the videos.     

Understanding use continuance in virtual worlds: Empirical test of a research model

We decided to examine why people continue to use virtual worlds by studying a real example: the popular virtual world of Second Life. This involved building and testing a model of virtual worlds based on habit from both the habit/automaticity and instant automaticity perspectives, the latter based on utilitarian and hedonic goals. The results (for a sample of 339 users) suggested that continuance intention for the virtual world was driven by perceived usefulness, enjoyment, and both perspectives of automatic behavior, which together provide considerable explanatory power for both habit and continuance intention. We conclude with implications for practice in this new area of inquiry.     

A model for the embedded tendon control of a slender three-dimensional flexible robot link

In this article we develop a model for a very flexible link that incorporates distributed controls and can be caused to achieve large transverse deflections as part of an overall control scheme. This ability opens the possibility of combining structural and position control actuator functions within a single lightweight physical device (with inextensible centerline). Emphasis is placed on presenting a basic model for this situation in terms and variables that are useful for integration with the conventions of conventional rigid-body robot dynamics.     

Nonlinear effects of thermo-sensitive nanobeams via a nonlocal thermoelasticity model with relaxation time

This paper presents a theoretical nonlocal model for a thermo-sensitive nanobeam based on the generalized thermoelasticity theory with thermal relaxation time. The present nanobeam is subjected to a sinusoidal pulse varying heat and its thermal conductivity is considered to be variable. This article deals with a nonlinear coupling partial differential equation since the thermal conductivity depends on temperature. The nonlocal theories of coupled thermoelasticity can be extracted as limited and special case of the present model. The effect of the variability thermal conductivity parameter, the nonlocal parameter, the relaxation time and the pulse width of the sinusoidal pulse on the distribution of lateral vibration, the temperature and the displacement of the nanobeam is investigated.     

Extending technology usage models to interactive hedonic technologies: a theoretical model and empirical test

Abstract. Much of our prior knowledge of information systems (IS) usage is based on utilitarian systems such as personal productivity software and organizational applications. However, new generations of systems, such as online video games (OVGs), have since emerged that aim at enhancing users' hedonic outcomes like entertainment rather than utilitarian outcomes such as productivity. Prior models of utilitarian system usage provide a limited understanding of one's usage of hedonic systems, given the motivational differences between using these two types of systems. Theoretical modifications instead are required to extend the current models to hedonic systems. Expanding the research on attitude theories, we propose an initial model for usage of interactive hedonic systems, replacing perceived usefulness and perceived ease of use with perceived enjoyment and social image as the core cognitive drivers of usage, and further linking these beliefs to different technological attributes. The initial model is empirically validated using a survey of OVG usage among 485 student subjects. For IS usage research, this paper proposes and validates one of the earliest usage models of hedonic systems. For practitioners, this study provides some guidelines for manufacturers of hedonic systems on how to derive the most return on their system development efforts.     

Automated debugging based on a constraint model of the program and a test case

Debugging, i.e., fault localization, in case of a detected failure is a time consuming and intricate task. The automation or at least partial automation of debugging is therefore highly desired. In this paper, we discuss some of the most recent approaches for debugging namely spectrum-based, slicing-based, and model-based debugging. We focus on the latter, and introduce the underlying theory as well as discuss empirical results obtained from our implementation. The model-based approach we present in this paper relies on a constraint representation of a program that is equivalent to the original program in terms of the input-output behavior under some reasonable assumptions. By using constraints for representing programs and subsequently test cases we are able to state the debugging problem as a constraint satisfaction problem that can be effectively solved using a todays constraint solver. The given empirical results indicate that the approach can be used for debugging smaller programs in less than 1 s. Moreover, we briefly compare the three approaches and suggest a combination of them in order to improve the results and the overall necessary running time.     

Proposing a test model for the computer graphics metafile

The Computer Graphics Metafile (CGM) is an international standard (CGM-ISO 8632) concerned with the storage and transfer of graphical data. It is specified in four parts, which describe the abstract specification and three encodings. The conformance testing of standards, in particular language standards and osi, is a rapidly growing area with many projects being undertaken worldwide. This paper proposes a strategy for testing implementations of the cgm. The first area considered is testing for conformance to the standard. The conclusion is soon reached that, due to the conformance statements within the cgm standard, only analysis (syntax and consistency checking) of the format of the metafile can be achieved. In order to provide more useful and practical information on cgm implementations, further testing is required. Hence, evaluation testing is introduced, and a model is described that could be used to give information on the capability of cgm generators and interpreters.     

X测试模型的改进与应用

针对目前常用的X测试模型结构松散和不够严谨的问题,提出了改进的X测试模型,能有效地规划测试工作和改善软件质量。改进的X测试模型在原模型基础上增加了回归测试和验收测试过程,对测试人员与测试方法间的关联进行了调整,强调客户的参与和测试需终止,从而解决了产品不符合客户要求、客户需求改变、测试效率低等问题。将改进的X模型应用于数字版权运营平台的开发测试中,应用结果表明,该模型提高了开发效率,保证了软件质量。     

Three empirical studies of a software reuse reference model

The contribution of this paper is a reference model for the practice of software reuse. Our research thesis is that software development based upon a software reuse reference model improves quality of products, productivity of processes and product time‐to‐market for many software development enterprises. The definition and investigation of such a model has been carried out using three steps. First, the reference model is developed based on existing software reuse concepts. Second, this reference model is empirically studied using both legacy studies and lessons learned studies. Third, the impact of the reference model on software development productivity, quality, and time‐to‐market is empirically derived. Copyright © 2000 John Wiley & Sons, Ltd.