3,974 research outputs found

    Presenting dcpos and dcpo algebras

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    Dcpos can be presented by preorders of generators and inequational relations expressed as covers. Algebraic operations on the generators (possibly with their results being ideals of generators) can be extended to the dcpo presented, provided the covers are “stable” for the operations. The resulting dcpo algebra has a natural universal characterization and satisfies all the inequational laws satisfied by the generating algebra. Applications include known “coverage theorems” from locale theory

    Borate based bioactive glass scaffolds for hard and soft tissue engineering

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    The main objectives of this dissertation were to evaluate bioactive borate glass scaffolds for hard and soft tissue applications and determine the potential toxicity of the borate glasses on the adjacent and systemic tissues. Porous randomly oriented fiber scaffolds composed of bioactive borate glass were implanted in subcutaneous soft tissue sites and in calvaria defects of laboratory rats and no signs of toxicity (necrotic tissue, increase in macrophages or other immune cells) were detected in any of the adjacent tissues (hard or soft). Systemic organs (kidney and liver) of laboratory rats implanted with bioactive borate scaffolds were analyzed for possible systemic toxicity and no adverse effects were found beyond normal incidental changes. Bone was found to grow statistically better (p\u3c0.05) in bioactive borate glass scaffolds when compared to similar scaffolds composed of borosilicate and silicate based bioactive glasses. For the first time, elements were added to a bioactive glass for the purposes of promoting angiogenesis. The elements copper and zinc were shown to significantly increase the number of blood vessels (p\u3c0.05) present in the soft tissue inside bioactive borate glass scaffolds when compared to the un-doped scaffolds. Bioactive borate glass fibers were also demonstrated as a new material that may be useful in the treatment of chronic wounds. A full thickness cutaneous defect (15mm diameter) on the back of a laboratory rats were healed in similar time (18 days), but with a higher quality scar than the control (untreated wound). The results from the full thickness cutaneous defect opens the door for new potential uses of bioactive borate glass fibers such as the treatment of chronic wounds and severe burns --Abstract, page v

    Prototype of Fault Adaptive Embedded Software for Large-Scale Real-Time Systems

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    This paper describes a comprehensive prototype of large-scale fault adaptive embedded software developed for the proposed Fermilab BTeV high energy physics experiment. Lightweight self-optimizing agents embedded within Level 1 of the prototype are responsible for proactive and reactive monitoring and mitigation based on specified layers of competence. The agents are self-protecting, detecting cascading failures using a distributed approach. Adaptive, reconfigurable, and mobile objects for reliablility are designed to be self-configuring to adapt automatically to dynamically changing environments. These objects provide a self-healing layer with the ability to discover, diagnose, and react to discontinuities in real-time processing. A generic modeling environment was developed to facilitate design and implementation of hardware resource specifications, application data flow, and failure mitigation strategies. Level 1 of the planned BTeV trigger system alone will consist of 2500 DSPs, so the number of components and intractable fault scenarios involved make it impossible to design an `expert system' that applies traditional centralized mitigative strategies based on rules capturing every possible system state. Instead, a distributed reactive approach is implemented using the tools and methodologies developed by the Real-Time Embedded Systems group.Comment: 2nd Workshop on Engineering of Autonomic Systems (EASe), in the 12th Annual IEEE International Conference and Workshop on the Engineering of Computer Based Systems (ECBS), Washington, DC, April, 200

    Efficient Model Selection in Linear and Non-Linear Quantile Regression by Cross-Validation

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    Check loss function is used to define quantile regression. In the prospect of cross validation, it is also employed as a validation function when underlying truth is unknown. However, our empirical study indicates that the validation with check loss often leads to choosing an over estimated fits. In this work, we suggest a modified or L2-adjusted check loss which rounds the sharp corner in the middle of check loss. It has a large effect of guarding against over fitted model in some extent. Through various simulation settings of linear and non-linear regressions, the improvement of check loss by L2 adjustment is empirically examined. This adjustment is devised to shrink to zero as sample size grows

    A novel boundary element method using surface conductive absorbers for full-wave analysis of 3-D nanophotonics

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    Fast surface integral equation (SIE) solvers seem to be ideal approaches for simulating 3-D nanophotonic devices, as these devices generate fields both in an interior channel and in the infinite exterior domain. However, many devices of interest, such as optical couplers, have channels that can not be terminated without generating reflections. Generating absorbers for these channels is a new problem for SIE methods, as the methods were initially developed for problems with finite surfaces. In this paper we show that the obvious approach for eliminating reflections, making the channel mildly conductive outside the domain of interest, is inaccurate. We describe a new method, in which the absorber has a gradually increasing surface conductivity; such an absorber can be easily incorporated in fast integral equation solvers. Numerical experiments from a surface-conductivity modified FFT-accelerated PMCHW-based solver are correlated with analytic results, demonstrating that this new method is orders of magnitude more effective than a volume absorber, and that the smoothness of the surface conductivity function determines the performance of the absorber. In particular, we show that the magnitude of the transition reflection is proportional to 1/L^(2d+2), where L is the absorber length and d is the order of the differentiability of the surface conductivity function.Comment: 10 page

    Wound Care

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    A method for treating a wound, and a dressing for wound care management comprising a three-dimensional body of glass-based fibers comprising one or more glass-formers selected from the group consisting of P2O5, SiO2, and B2O3; at least about 25 wt % of the fibers have a diameter between about 200 nm and about 4000 nm, and a length:width aspect ratio of at least about 10. In another form, the glasses are in the form of particles in an ointment or cream applied to a wound. In yet other forms the glasses are employed as fibers formed into sutures for closing a wound, or as particles in a surgical glue for closing a wound
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