Software maintenance: the need for standardization

Procedures are proposed to assist the Navy Management Systems Support Office in performing software maintenance. Hardware and software maintenance are contrasted. The key difference between the two -- the ease which software can be changed -- leads to the need for managing software change. Standardization of software is proposed as the method for managing software change. A model of software maintenance is advanced as the function for standardizing software maintenance. (kr)Prepared for: Navy Management Systems Support Office, Norfolk, VAhttp://archive.org/details/softwaremaintenanc00schnApproved for public release; distribution is unlimited

The state of software maintenance

A state of software maintenance survey is presented, indicating the incongruity of the simultaneous existence of important and neglect in this field. An overview is given of selected developments and activities covering the following topics: the "Maintenance Problem", models, methods for improving maintenance, metrics, maintenance information management, standards, maintenance of existing code, and surveys. The paper concludes with a prognosis of what is ahead in maintenance: a battle and tradeoff between the forces for maintaining the base of existing software and the forces for the evolution of new systems. An Appendix is provided for the reader who desires information about a software maintenance conference and a special interest group

An approach to software reliability prediction and quality control

December 5-7, 1972, Fall Joint Computer ConferenceThe increase in importance of software in command and control and other complex systems has not been accompanied by commensurate progress in the develop- ment of analytical techniques for the measurement of software quality and the prediction of software reliability. This paper presents a rationale for imple- menting software reliability programs; defines software reliability; and describes some of the problems of performing software reliability analysis. A software reliability program is outlined and a methodology for reliability prediction and quality control is presented. The results of initial efforts to develop a software reliability methodology at the Naval Electronics Laboratory Center are reported

Computer System Testing

Increasingly, the quantitative evaluation of computer software is recognized as critically important to the effective functioning of computer systems. At NPS, the model for statistically analyzing software error detection and correction processes during software functional testing has been developed. The model provides decision aids for controlling the quality ofcommand and control system software. The inputs to the model are error detection histories and the outputs are forecasts of the future behavior of error detection and correction processes

Spin reorientation in Na-doped BaFe2_2As2_2 studied by neutron diffraction

We have studied the magnetic ordering in Na doped BaFe$_2$As$_2$ by unpolarized and polarized neutron diffraction using single crystals. Unlike previously studied FeAs-based compounds that magnetically order, Ba$_{1-x}$Na$_x$Fe$_2$As$_2$ exhibits two successive magnetic transitions: For x=0.35 upon cooling magnetic order occurs at $\sim$70\ K with in-plane magnetic moments being arranged as in pure or Ni, Co and K-doped BaFe$_2$As$_2$ samples. At a temperature of $\sim$46\ K a second phase transition occurs, which the single-crystal neutron diffraction experiments can unambiguously identify as a spin reorientation. At low temperatures, the ordered magnetic moments in Ba$_{0.65}$Na$_{0.35}$Fe$_2$As$_2$ point along the $c$ direction. Magnetic correlations in these materials cannot be considered as Ising like, and spin-orbit coupling must be included in a quantitative theory.Comment: 5 pages, 4 figure

Analysis of computer performance in multiprogrammed processing

An analysis was made of the correlation between performance and resource usage variables of a given computer job and between the performance variables of a given job and the resource usage variables of other jobs in a multiprogramming environment. This analysis was performed in order to: (1) determine the mix and characteristics of jobs which lead to high performance, (2) provide regression equation predictors of performance for given resource utilizations, and (3) provide performance and resource utilization coefficients for use in a linear programming resource allocation model. The linear programming model is used to select an optimum job mix subject to production, resource usage and budgetary constraints. (Author)Nava1 Weapons Center, China Lake, Californiahttp://archive.org/details/analysisofcomput00schnN60530 72PO-2-0056N

The Two-Dimensional Square-Lattice S=1/2 Antiferromagnet Cu(pz)2_2(ClO4_4)2_2

We present an experimental study of the two-dimensional S=1/2 square-lattice antiferromagnet Cu(pz)$_2$(ClO$_4$)$_2$ (pz denotes pyrazine - $C_4H_4N_2$) using specific heat measurements, neutron diffraction and cold-neutron spectroscopy. The magnetic field dependence of the magnetic ordering temperature was determined from specific heat measurements for fields perpendicular and parallel to the square-lattice planes, showing identical field-temperature phase diagrams. This suggest that spin anisotropies in Cu(pz)$_2$(ClO$_4$)$_2$ are small. The ordered antiferromagnetic structure is a collinear arrangement with the magnetic moments along either the crystallographic b- or c-axis. The estimated ordered magnetic moment at zero field is m_0=0.47(5)mu_B and thus much smaller than the available single-ion magnetic moment. This is evidence for strong quantum fluctuations in the ordered magnetic phase of Cu(pz)$_2$(ClO$_4$)$_2$. Magnetic fields applied perpendicular to the square-lattice planes lead to an increase of the antiferromagnetically ordered moment to m_0=0.93(5)mu_B at mu_0H=13.5T - evidence that magnetic fields quench quantum fluctuations. Neutron spectroscopy reveals the presence of a gapped spin excitations at the antiferromagnetic zone center, and it can be explained with a slightly anisotropic nearest neighbor exchange coupling described by J_1^{xy}=1.563(13)meV and J_1^z=0.9979(2)J_1^{xy}

Predicting Deviations in Software Quality by Using Relative Critical Value Deviation Metrics

Abstract We develop a new metric, Relative Critical Value Deviation (RCVD

Neutron scattering study of commensurate magnetic ordering in single crystal CeSb2_2

Temperature and field-dependent magnetization $M(H,T)$ measurements and neutron scattering study of a single crystal CeSb$_2$ are presented. Several anomalies in the magnetization curves have been confirmed at low magnetic field, i.e., 15.6 K, 12 K, and 9.8 K. These three transitions are all metamagnetic transitions (MMT), which shift to lower temperatures as the magnetic field increases. The anomaly at 15.6 K has been suggested as paramagnetic (PM) to ferromagnetic (FM) phase transition. The anomaly located at around 12 K is antiferromagnetic-like transition, and this turning point will clearly split into two when the magnetic field $H\geq0.2$ T. Neutron scattering study reveals that the low temperature ground state of CeSb$_2$ orders antiferromagnetically with commensurate propagation wave vectors $\textbf{k}=(-1,\pm1/6,0)$ and $\textbf{k}=(\pm1/6,-1,0)$, with N\'eel temperature $T_N\sim9.8$ K. This transition is of first-order, as shown in the hysteresis loop observed by the field cooled cooling (FCC) and field cooled warming (FCW) processes.Comment: 7 pages,9 figure