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The advantages of using a multi‐CPU concurrent computer in solving a steady state free surface seepage problem are studied. The underlying computational task is the solution of a large set of linear equations with a projection operation numerous times. In the study, both Jacobi and SOR iteration methods with projection in a modified alternating iteration scheme are used to solve the problem with varied number of nodes (CPUs) and the timing results are compared between a 32 node Hypercube Concurrent Computer and a VAX 11/780 (single CPU). In addition, the performance and the feasibility of the Hypercube Concurrent Computer are discussed by comparing with the number of nodes used and with the VAX 11/780.

Distributed control is an effective method for controlling and suppressing excessive vibrations of continuous systems. Optimal distributed control for a plate problem is solved utilizing a maximum principle after the introduction of a quadratic index of performance in terms of displacement, velocity and a control force as well as an adjoint variable. The problem is reduced to solving a system of partial differential equations for the state variable and the adjoint variable subjected to boundary, initial and terminal conditions. A numerical algorithm is presented to solve the optimal distributed control problem in the space‐time domain which reduces the computational effort required to solve the initial‐terminal‐boundary value problem. Results obtained for a simply supported, rectangular, thin plate are also presented.

Presents numerical algorithms which easily solve both optimal distributed and optimal boundary control problems in a space‐time domain. Analyses two simple cases of continuous systems. These are the vibrating string and the axially vibrating rod. Using finite difference recurrence schemes, gives numerical results which compare the behaviour of the controlled and uncontrolled systems. Compares the results for special cases in which analytical solutions are obtainable are compared with the results using the general numerical schemes.

A numerical solution to the free boundary problem of three‐dimensional transient seepage through an earth dam with accretion is presented. The numerical model uses a Baiocchi type transformation to extend the unknown solution region to a fixed known region. The initial value problem is then solved by an iterative method of successive over‐relaxation type. A seepage situation of sudden rise of water level on one side of a dam is presented as an example problem. The effects of variation of accretion, effective porosity and hydraulic conductivity are studied.

If rational individuals pay the full costs of their decisions about food intake and exercise, economists, policy makers, and public health officials should treat the obesity epidemic as a matter of indifference. In this paper, we show that, as long as insurance premiums are not risk rated for obesity, health insurance coverage systematically shields those covered from the full costs of physical inactivity and overeating. Since the obese consume significantly more medical resources than the non-obese, but pay the same health insurance premiums, they impose a negative externality on normal weight individuals in their insurance pool.

To estimate the size of this externality, we develop a model of weight loss and health insurance under two regimes – (1) underwriting on weight is allowed and (2) underwriting on weight is not allowed. We show that under regime (1), there is no obesity externality. Under regime (2), where there is an obesity externality, all plan participants face inefficient incentives to undertake unpleasant dieting and exercise. These reduced incentives lead to inefficient increases in bodyweight, and reduced social welfare.

Using data on medical expenditures and bodyweight from the National Health and Interview Survey and the Medical Expenditure Panel Survey, we estimate that, in a health plan with a coinsurance rate of 17.5%, the obesity externality imposes a welfare cost of about $150 per capita. Our results also indicate that the welfare loss can be reduced by technological change that lowers the pecuniary and non-pecuniary costs of losing weight, and also by increasing the coinsurance rate.

To provide an excellent numerical method to simulate an important industrial process – wet chemical etching problem.

A mathematical model describing the wet chemical etching process is formulated in terms of a parabolic variational inequality and a non‐overlapping domain decomposition (DD) method is proposed in the etching region, where a partial differential equation is treated in one sub‐domain, while a variational inequality is considered in the second sub‐domain. A Robin boundary condition with a parameter whose optimal value is to be found is enforced on the common boundary between these two sub‐domains. Finite difference technique with projection and the Crank‐Nicholson scheme for the time discretization are the major numerical tools utilized in this paper.

The proposed numerical method has achieved the best numerical performance for the famous wet chemical etching process among all the numerical schemes applied to this problem. It also shows the great computational power of domain splitting technique.

Lack of parallel supercomputer system limits the authors to perform further numerical tests with extremely large data. This will be done in the future.

This is a very useful paper for the academic researchers and industry engineers who wish to develop more advanced numerical methods to simulate various kinds of industry processes along the research direction from this paper.

This paper provides a new and promising version of DD method in the field of moving boundary problems and offers a practical way to simulate wet chemical etching process for the engineers and scientists in the related field.

This paper follows previous economic studies on bodyweight by looking at bodyweight as individuals’ choices in response to changes in income and food prices. However, it goes one step further to add another relevant choice under individual control: food quality. It shows that the upward trend of bodyweight caused by economic growth and technological innovations may well be self-limiting in the sense that the bodyweight growth in the future is likely to be slower or reversed. In particular, it finds that much of further income growth will be used for improving food quality rather than increasing caloric intake. Moreover, further technological innovations that focus on lowering the price of high-quality (healthy) food relative to that of low-quality food would encourage substituting food quality for food quantity (calories).

The purpose of this paper is to propose an optimization method by combining artificial immune algorithm and finite element analysis to find the optimal exciting electrode of a piezoceramic plate type ultrasonic motor vibrator.

The artificial immune algorithm is selected as optimizer for its merit of fast convergence to global optimal solution. The finite element analysis is used to calculate the motion trajectory of contact point. The objective function is the work that the vibrator does to rotor. The design variables are the boundaries of exciting electrode on piezoceramic plate vibrator surface.

The calculated results and the experimental results show that using this method, both the position and the size of optimal exciting electrode of this ultrasonic motor can be quickly and accurately determined.

In order to successfully design an ultrasonic motor, both the position and the size of the exciting electrode must be investigated, so as to change more electric energy into mechanical energy. In this paper, an optimization method by combining artificial immune algorithm and finite element analysis is proposed for the exciting location optimization of a piezoceramic plate type ultrasonic motor to obtain large power output.

Racial and ethnic minorities utilize less healthcare than their similarly situated white counterparts in the United States, resulting in speculation that these actions may stem in part from less desire for care. In order to adequately understand the role of care-seeking for racial and ethnic disparities in healthcare, we must fully and systematically consider the complex set of social factors that influence healthcare seeking and use.

Data for this study come from a 2005 national survey of community-dwelling Medicare beneficiaries (N = 2,138). We examine racial and ethnic variation in intentions to seek care, grounding our analyses in the behavioral model of healthcare utilization. Our analysis consists of a series of nested multivariate logistic regression models that follow the sequencing of the behavioral model while including additional social factors.

We find that Latino, Black, and Native American older adults express greater preferences for seeking healthcare compared to whites. Worrying about one’s health, having skepticism toward doctors in general, and living in a small city rather than a Metropolitan Area, but not health need, socioeconomic status, or healthcare system characteristics, explain some of the racial and ethnic variation in care-seeking preferences. Overall, we show that even after comprehensively accounting for factors known to influence disparities in utilization, elderly racial and ethnic minorities express greater desire to seek care than whites.

We suggest that future research examine social factors such as unmeasured wealth differences, cultural frameworks, and role identities in healthcare interactions in order to understand differences in care-seeking and, importantly, the relationship between care-seeking and disparities in utilization.

This study represents a systematic analysis of the ways individual, social, and structural context may account for racial and ethnic differences in seeking medical care. We build on healthcare seeking literature by including more comprehensive measures of social relationships, healthcare and system-level characteristics, and exploring a wide variety of health beliefs and expectations. Further, our study investigates care seeking among multiple understudied racial and ethnic groups. We find that racial and ethnic minorities are more likely to say they would seek healthcare than whites, suggesting that guidelines promoting the elicitation and understanding of patient preferences in the context of the clinical interaction is an important step toward reducing utilization disparities. These findings also underscore the notion that health policy should go further to address the broader social factors relating to care-seeking in the first place.