No Science without Semantics

Computer science often faces the criticism that it isn't actual science. Doing science means using the scientific method, which includes reporting results so that others can repeat and verify them. The problem with the computer science community is the lack of shared terms with precise semantics. When a researcher reports phenomenal results that can't be replicated, the author might be viewed as a brilliant alchemist, but such works undermine claims of being "science."     

Comparative study on adaptive rational macromodels of highly resonant structures

Two macromodeling techniques using rational bases are investigated to accurately predict the natural frequencies of highly resonant microwave structures. Three methods are proposed and compared to calculate pole‐free solutions to the Thiele continued fraction and vector fitting pole‐residue models of the characteristic equation det[Z(s)]. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

用于木材粘接的反应型聚氨酯胶粘剂

本文讨论了反应型聚氨酯胶粘剂的配方及其在木材粘接中应用。重点讨论单组分液体型、热熔型和木材复合板粘接用反应型、湿气固化聚氨酯胶粘剂。     

The utility of the composite cascode in analog CMOS design

This work demonstrates the utility of the composite cascode stage by considering its use (1) as a high-gain amplifying stage; (2) as a high-impedance load for an amplifying stage; and (3) as a low-impedance, high-frequency summing circuit. A simulation of the summing circuit using 0.18?µm channel lengths leads to a rise time of less than 30?ps and good linearity. When used as a high-gain amplifier, both devices of the active cascode stage must be biased into the active region. In the summing circuit, one device is biased into the triode region whereas the second device must operate in the active region. Guidelines for achieving proper bias with a single bias source are provided in this work.     

Sympathetic response to stimulation of the pontine A5 region in conscious rabbits

OBJECT: This study is a retrospective analysis of clinical data obtained in 28 patients affected by obstructive hydrocephalus who presented with signs of midbrain dysfunction during episodes of shunt malfunction. METHODS: All patients presented with an upward gaze palsy, sometimes associated with other signs of oculomotor dysfunction. In seven cases the ocular signs remained isolated and resolved rapidly after shunt revision. In 21 cases the ocular signs were variably associated with other clinical manifestations such as pyramidal and extrapyramidal deficits, memory disturbances, mutism, or alterations in consciousness. Resolution of these symptoms after shunt revision was usually slow. In four cases a transient paradoxical aggravation was observed at the time of shunt revision. In 11 cases ventriculocistemostomy allowed resolution of the symptoms and withdrawal of the shunt. Simultaneous supratentorial and infratentorial intracranial pressure recordings performed in seven of the patients showed a pressure gradient between the supratentorial and infratentorial compartments, with a higher supratentorial pressure before shunt revision. Inversion of this pressure gradient was observed after shunt revision and resolution of the gradient was observed in one case after third ventriculostomy. In six recent cases, a focal midbrain hyperintensity was evidenced on T2-weighted magnetic resonance imaging sequences at the time of shunt malfunction. This rapidly resolved after the patient underwent third ventriculostomy. CONCLUSIONS: It is probable that in obstructive hydrocephalus, at the time of shunt malfunction, the development of a transtentorial pressure gradient could initially induce a functional impairment of the upper midbrain, inducing upward gaze palsy. The persistence of the gradient could lead to a global dysfunction of the upper midbrain. Third ventriculostomy contributes to equalization of cerebrospinal fluid pressure across the tentorium by restoring free communication between the infratentorial and supratentorial compartments, resulting in resolution of the patient's clinical symptoms.     

Symmetry Definitions for Constraint Satisfaction Problems

We review the many different definitions of symmetry for constraint satisfaction problems (CSPs) that have appeared in the literature, and show that a symmetry can be defined in two fundamentally different ways: as an operation preserving the solutions of a CSP instance, or else as an operation preserving the constraints. We refer to these as solution symmetries and constraint symmetries. We define a constraint symmetry more precisely as an automorphism of a hypergraph associated with a CSP instance, the microstructure complement. We show that the solution symmetries of a CSP instance can also be obtained as the automorphisms of a related hypergraph, the k-ary nogood hypergraph and give examples to show that some instances have many more solution symmetries than constraint symmetries. Finally, we discuss the practical implications of these different notions of symmetry.