Formalizing structured file services for the data storage and retrieval subsystem of the data management system for Spacestation Freedom

A brief example of the use of formal methods techniques in the specification of a software system is presented. The report is part of a larger effort targeted at defining a formal methods pilot project for NASA. One possible application domain that may be used to demonstrate the effective use of formal methods techniques within the NASA environment is presented. It is not intended to provide a tutorial on either formal methods techniques or the application being addressed. It should, however, provide an indication that the application being considered is suitable for a formal methods by showing how such a task may be started. The particular system being addressed is the Structured File Services (SFS), which is a part of the Data Storage and Retrieval Subsystem (DSAR), which in turn is part of the Data Management System (DMS) onboard Spacestation Freedom. This is a software system that is currently under development for NASA. An informal mathematical development is presented. Section 3 contains the same development using Penelope (23), an Ada specification and verification system. The complete text of the English version Software Requirements Specification (SRS) is reproduced in Appendix A

Electronic structure and properties of (TiZrNbCu)_1-xNi_x high entropy amorphous alloys

A comprehensive study of selected properties of four (TiZrNbCu)_1-xNi_x (x \le 0.25) amorphous high entropy alloys (a-HEA) has been performed. The samples were ribbons about 20 \mum thick and their fully amorphous state was verified by X-ray diffraction and thermal analysis. The surface morphology, precise composition and the distribution of components were studied with a Scanning electron microscope (SEM) with an energy dispersive spectroscopy (EDS) attachment. The properties selected were the melting temperature (T_m), the low temperature specific heat (LTSH), the magnetic susceptibility \chi_exp and the Young^,s modulus (E). Whereas LTSH and \chi_exp were measured for the as-cast samples, E was measured both for as-cast samples and relaxed samples (after a short anneal close to the glass transition temperature). The LTSH showed that the electronic density of states at the Fermi level, N_0(E_F), decreases with increasing x, whereas the Debye temperature (\theta_D) increases with x. This is similar to what is observed in binary and ternary amorphous alloys of early transition metals (TE) with late transition metals (TL) and indicates that N_0(E_F) is dominated by the d-electrons of the TE. The LTSH also showed the absence of superconductivity down to 1.8K and indicated the emergence of the Boson peak above 4K in all alloys.The free-electron like paramagnetic contribution to \chi_exp also decreases with x, whereas E, like \theta_D, increases with x, indicating enhanced interatomic bonding on addition of Ni. The applicability of the rule of mixtures to these and other similar HEAs is briefly discussed

Pneumatic Non-Contact Measuring System for In-Process Dimensions Measurements

Abstract Pneumatic non-contact measuring systems are applied for automatic inspection for dimensions and forms. The dynamic characteristics of the systems were studied analytically and experimentally. Analytical relations considered the effect of the systems design parameters and measuring speeds on the system performance; measuring range, sensitivity and response time. Sets of experiments were performed at different measuring speeds on machined parts having different dimensions and forms. Comparison between the experimental and analytical results was performed. The experimental results showed conformity with those derived analytically. Pattern recognition methods were used to correlate the pressure variation with the measured dimensions and forms

Disfavoring Statutory Parentheses (Except in Certain Circumstanaces)

Parentheses in statutes have been at issue in an increasing number of court cases, even at the Supreme Court. Parentheses have a slightly different story from other punctuation marks and they have been used consistently throughout legal history. The Federal Constitution, early statutes, and a large part of our modern state and federal law separate words from their sentences using parentheses. But if a parenthetical conflicts with the material outside of the parentheses, it is the current practice to discard the interior text as surplus-age, even though the legislature may have had a reason to include that text in a statute. Interpreters should instead determine what use the parentheses play in the statute. Should the parenthetical text include a definition or an exemption, the parenthetical should control. But if it serves a descriptive purpose, the parenthetical text should be disfavored. This Note proposes a canon of construction that articulates the presumption against using conflicting parenthetical text in statutes (except in certain circumstances)