Noisy image restoration by cost function minimization

Implementation of a new approach to the nonlinear noisy image restoration problem, which is feasible for large images, is described. The approach is based on a vector space representation of images and on using the conjugate gradient algorithm to solve a least squares minimization problem. Computer simulations yield good results with relatively little computational cost.     

Asymptotic and finite element approximations for heat transfer in rotating compressible flow over an infinite porous disk

The laminar boundary layer equations for the compressible flow due to the finite difference in rotation and temperature rates are solved for the case of uniform suction through the disk. The effects of viscous dissipation on the incompressible flow are taken into account for any rotation rate, whereas for a compressible fluid they are considered only for a disk rotating in a stationary fluid. For the general case, the governing equations are solved numerically using a standard finite element scheme. Series solutions are developed for those cases where the suction effect is dominant. Based on the above analytical and numerical solutions, a new asymptotic finite element scheme is presented. By using this scheme one can significantly improve the pointwise accuracy of the standard finite element scheme.     

Local application of honey for treatment of neonatal postoperative wound infection

Radiofrequency catheter ablation has been useful in the treatment of ventricular tachycardia (VT) in selected patients with healed myocardial infarction. Previous studies have demonstrated success rates of 60% to 96% for targeted VT morphologies; however, these studies included patients only after they have had successful mapping procedures and have received radiofrequency lesions. All patients referred for VT ablation from July 1992 to November 1996 were included in this analysis on an intention-to-treat basis. Ninety-five procedures were performed in 66 patients for 77 distinct presentations with tolerated, sustained VT. Fifty-five procedures were successful (58%) and 40 procedures failed. Reasons for procedural failure included failed radiofrequency application despite adequate VT mapping (21 procedures), no tolerated VT induced (12), and aborted procedures due to complications or technical difficulties (7). Fifty-five patients (71%) eventually had a successful VT ablation, although 10 required > 1 procedure. This analysis revealed factors that contribute to failure of VT ablation procedures in addition to inadequate mapping and lesion formation. Procedural difficulties, particularly the inability to induce tolerated VT, frequently prevent successful catheter ablation in patients who present with tolerated, sustained VT.     

The effect of precursory cooling on rewetting of a slab

The Dua and Tien (1976) model for the rewetting of a slab with precursory cooling is solved exactly by separation of variables. The solution for the rewetting velocity is found to agree very well with a Wiener Hopf technique solution to this model by the author. Rewetting rates predicted by the approximate solution of Dua and Tien are found to agree with the present solution for small Peclet numbers, while underpredicting them for large Peclet numbers. Theoretical quench front velocities compare favorably with experimental data for copper quenched by liquid nitrogen. Precursory cooling is shown to be able to greatly increase the rewetting velocity, in particular for cases of high flow rates, while neglecting it in modelling may result in much too low quench velocities, as compared to experimental measurements.     

Reducing muscle fatigue in FES applications by stimulating withN-let pulse trains

Applications of electrical stimulation for restoration of functional movements such as standing, gait, and grasp have always been hindered by the rapid fatigue of stimulated muscle. This paper describes an experimental investigation of stimulation with N-lets (a set of N closely spaced stimulation pulses) as a means of producing contractions with improved fatigue characteristics. Experiments were conducted on 27 able-bodied and four SCI human subjects using surface stimulation of the quadriceps muscle to produce isometric knee joint torque. Based upon evidence from the literature on muscle fatigue, parameters of the N-let trains for N=1-6 were optimized to produce the most force per pulse. The results demonstrated that: 1) nonlinear summation of the twitch response occurs in human subjects with N-let surface stimulation; 2) for most subjects, doublet stimulation (N=2) with a pulse interval of about 5 ms produced the maximum torque-time integral per pulse of the resulting twitch; and 3) on average, optimal N-let stimulation resulted in a 36% increase in isometric torque tracking when compared to traditional singlet stimulation. The results have immediate implications for alleviating the problem of premature fatigue during functional electrical stimulation     

A novel model-based testing approach for software product lines

Model-based testing relies on a model of the system under test. FineFit is a framework for model-based testing of Java programs. In the FineFit approach, the model is expressed by a set of tables based on Parnas tables. A software product line is a family of programs (the products) with well-defined commonalities and variabilities that are developed by (re)using common artifacts. In this paper, we address the issue of using the FineFit approach to support the development of correct software product lines. We specify a software product line as a specification product line where each product is a FineFit specification of the corresponding software product. The main challenge is to concisely specify the software product line while retaining the readability of the specification of a single system. To address this, we used delta-oriented programming, a recently proposed flexible approach for implementing software product lines, and developed: (1) delta tables as a means to apply the delta-oriented programming idea to the specification of software product lines; and (2) DeltaFineFit as a novel model-based testing approach for software product lines.     

Energy-optimal collaborative file distribution in wired networks

The impact of the ICT sector in worldwide power consumption is an increasing concern, motivating the research community to devote an important effort to define novel energy efficient networking solutions. Despite file distribution is responsible for a major portion of the current Internet traffic, little effort has been dedicated to address the issue of its energy efficiency so far. Most of the previous literature focuses on optimizing the download time of file distribution schemes (e.g. centralized server-based or distributed peer-to-peer solutions) while it is yet unclear how to optimize file distribution schemes from the point of view of energy consumed. In this paper, we present a general modelling framework to analyze the energy consumption of file distribution systems. First, we show that the general problem of minimizing energy consumption in file distribution is NP-hard. Then, for restricted versions of the problem, we establish theoretical bounds to minimal energy consumption. Furthermore, we define a set of optimal algorithms for a variety of system settings, which exploit the service capabilities of hosts in a P2P fashion. We show that our schemes are capable of reducing at least 50 % of the energy consumed by traditional (yet largely used) centralized distribution schemes even when considering effects such as network congestion and heterogeneous access speed across nodes.     

The languages FCP(:) and FCP(:,?)

The language FCP(:,?) is the outcome of attempts to integrate the best of several flat concurrent logic programming languages, including Flat GHC, FCP (↓, |) and Flat Concurrent Prolog, in a single consistent framework. FCP(:) is a subset of FCP(:, ?), which is a variant of FPP(↓, |) and employs concepts of the concurrent constraint framework of cc(↓, |). FCP(:, ?) is a language which is strong enough to accommodate all useful concurrent logic programming techniques, including those which rely on atomic test unification and read-only variables, yet incorporates the weaker languages mentioned as subsets. This allows the programmer to remain within a simple subset of the language such as Flat GHC when the full power of atomic unification or read-only variables is not needed.