Change Management Support for Large Software Systems

This technical report consists of three related papers in the area of management of source code changes for large software systems. Infuse: A Toolfor Automatically Managing and Coordinating Source Changes in Large Systems presents Infuse, a software engineering environment that automatically panitions the source code files to be changed in order to limit the complexity of change propagation and negotiation of conflicting changes. Workspaces and Experimental Databases: Automated Support for Cooperation Among Programmers describes Infuse in more detail, focusing on the interactions between Infuse and source code modification tools. Smarter Recompilation presents an algorithm that could be used by Infuse or other software engineering environments to reduce recompilation costs after source code changes

Distribution of selected healthcare resources for influenza pandemic response in Cambodia.

INTRODUCTION: Human influenza infection poses a serious public health threat in Cambodia, a country at risk for the emergence and spread of novel influenza viruses with pandemic potential. Prior pandemics demonstrated the adverse impact of influenza on poor communities in developing countries. Investigation of healthcare resource distribution can inform decisions regarding resource mobilization and investment for pandemic mitigation. METHODS: A health facility survey performed across Cambodia obtained data on availability of healthcare resources important for pandemic influenza response. Focusing on five key resources considered most necessary for treating severe influenza (inpatient beds, doctors, nurses, oseltamivir, and ventilators), resource distributions were analyzed at the Operational District (OD) and Province levels, refining data analysis from earlier studies. Resources were stratified by respondent type (hospital vs. District Health Office [DHO]). A summary index of distribution inequality was calculated using the Gini coefficient. Indices for local spatial autocorrelation were measured at the OD level using geographical information system (GIS) analysis. Finally, a potential link between socioeconomic status and resource distribution was explored by mapping resource densities against poverty rates. RESULTS: Gini coefficient calculation revealed variable inequality in distribution of the five key resources at the Province and OD levels. A greater percentage of the population resides in areas of relative under-supply (28.5%) than over-supply (21.3%). Areas with more resources per capita showed significant clustering in central Cambodia while areas with fewer resources clustered in the northern and western provinces. Hospital-based inpatient beds, doctors, and nurses were most heavily concentrated in areas of the country with the lowest poverty rates; however, beds and nurses in Non-Hospital Medical Facilities (NHMF) showed increasing concentrations at higher levels of poverty. CONCLUSIONS: There is considerable heterogeneity in healthcare resource distribution across Cambodia. Distribution mapping at the local level can inform policy decisions on where to stockpile resources in advance of and for reallocation in the event of a pandemic. These findings will be useful in determining future health resource investment, both for pandemic preparedness and for general health system strengthening, and provide a foundation for future analyses of equity in health services provision for pandemic mitigation planning in Cambodia

Interrelationships of plant population, soil moisture and soil fertility in determining corn yields on Colo clay loam at Ames, Iowa

This investigation included a 6-year study of the effects of irrigation, stand and fertility treatments on com yields on a clay loam soil near Ames, Iowa. The data obtained from 1956 to 1961 indicated that variations in yields were caused by all three variables. Significant yield differences caused by irrigation treatments were greatest in 1956, 1959 and 1960. The highest mean irrigated yields averaged over stand and fertility treatments usually correlated best with the irrigation treatment where the soil moisture was maintained at or above 60 percent of the available moisture content (AMC). The greatest yield response to irrigation occurred in 1956, primarily because of the very dry conditions throughout the entire growing season. In 1956, each inch of water increased yield by 2.7 bushels per acre up to the 60-percent AMC level. Beyond this point, maintaining soil moisture at 90 percent or greater of field capacity reduced yield per increment of added water. There was not a significant response to irrigation in 1957, 1958 and 1961, primarily because of ample soil moisture storage and good rainfall distribution at critical periods during the growing season

No effect of pre race supplementation with vitamins and minerals on performance in an ultra-endurance race

Intake of supplements such as vitamins and minerals is widespread in athletes. The aim of the study was the investigation of the influence of intake of vitamins and minerals before an ultra-endurance triathlon and its effect on race performance in a descriptive field study. Participants of the “Triple Iron Triathlon Germany 2006“ in Lensahn, Schleswig-Holstein, Germany, were contacted by a newsletter six weeks before the race by the organizer and received a questionnaire to fill in their intake of vitamins and minerals. Questionnaires were self-administered and not administered by trained personnel. During this race the athletes had to cover 11.4 km swimming, 540 km cycling and 126.6 km running within 58 hours. The athletes were divided into two categories: successful finishers with intake of vitamins and minerals and successful finishers without intake prior to the race. Race performance (total running time in h) of athletes with intake and athletes without intake of these substances was compared. In the four-week period prior to the race, nine athletes (53 %) ingested vitamins and eight athletes (47 %) minerals. Athletes with intake of vitamins (44.7 ± 7.0 h versus 50.4 ± 4.4h; p>0.05) and minerals (45.3 ± 7.2 versus 49.3 ± 5.4 h, p>0.05) finished the race not faster than athletes without intake of vitamins and minerals. In the “Triple Iron Triathlon Germany 2006“ in Lensahn, Germany, no influence on race performance was observed concerning the regular intake of vitamins and minerals in the last four weeks before the race

A model for inter-module analysis and optimizing compilation

Recent research into the implementation of logic programming languages has demonstrated that global program analysis can be used to speed up execution by an order of magnitude. However, currently such global program analysis requires the program to be analysed as a whole: sepárate compilation of modules is not supported. We describe and empirically evalúate a simple model for extending global program analysis to support sepárate compilation of modules. Importantly, our model supports context-sensitive program analysis and multi-variant specialization of procedures in the modules

Modelling adapted to manufacturing aspects of holographic grating structures

The diffraction efficiencies of modified sinusoidal and blazed gratings are investigated in the high spatial frequency regime by rigorous numerical methods and are compared to experimentally manufactured gratings. The introduced modifications take actual technological induced variations of the profile geometries, such as specific corner rounding, into account. The high spatial frequency regime (resonance regime) is characterized by a local grating period, g, to wavelength, λ, ratio of 0.7 ≤ g/λ ≤ 4 and shows an important relevance for applications in spectroscopy and diffractive imaging. The investigations are carried out for both reflection on metallic surfaces and transmission of dielectric structures over a broad range of grating periods and incidence angles. It was found that near the grating resonance, the more simply producible sine gratings can compete in diffraction efficiency with sawtooth structures. Additionally, for certain application conditions, holographically modified sine structures achieve higher efficiencies than the ideal sine profile. It is also shown that holographical sinusoidal-like profiles measured by AFM can be fitted to a super-Gaussian shape, which is then used to inversely reconstruct the structure profiles from efficiency data

Aging Studies for the Large Honeycomb Drift Tube System of the Outer Tracker of HERA-B

The HERA-B Outer Tracker consists of drift tubes folded from polycarbonate foil and is operated with Ar/CF4/CO2 as drift gas. The detector has to stand radiation levels which are similar to LHC conditions. The first prototypes exposed to radiation in HERA-B suffered severe radiation damage due to the development of self-sustaining currents (Malter effect). In a subsequent extended R&D program major changes to the original concept for the drift tubes (surface conductivity, drift gas, production materials) have been developed and validated for use in harsh radiation environments. In the test program various aging effects (like Malter currents, gain loss due to anode aging and etching of the anode gold surface) have been observed and cures by tuning of operation parameters have been developed.Comment: 14 pages, 6 figures, to be published in the Proceedings of the International Workshop On Aging Phenomena In Gaseous Detectors, 2-5 Oct 2001, Hamburg, German

The Outer Tracker Detector of the HERA-B Experiment Part I: Detector

The HERA-B Outer Tracker is a large system of planar drift chambers with about 113000 read-out channels. Its inner part has been designed to be exposed to a particle flux of up to 2.10^5 cm^-2 s^-1, thus coping with conditions similar to those expected for future hadron collider experiments. 13 superlayers, each consisting of two individual chambers, have been assembled and installed in the experiment. The stereo layers inside each chamber are composed of honeycomb drift tube modules with 5 and 10 mm diameter cells. Chamber aging is prevented by coating the cathode foils with thin layers of copper and gold, together with a proper drift gas choice. Longitudinal wire segmentation is used to limit the occupancy in the most irradiated detector regions to about 20 %. The production of 978 modules was distributed among six different laboratories and took 15 months. For all materials in the fiducial region of the detector good compromises of stability versus thickness were found. A closed-loop gas system supplies the Ar/CF4/CO2 gas mixture to all chambers. The successful operation of the HERA-B Outer Tracker shows that a large tracker can be efficiently built and safely operated under huge radiation load at a hadron collider.Comment: 28 pages, 14 figure

The Outer Tracker Detector of the HERA-B Experiment. Part II: Front-End Electronics

The HERA-B Outer Tracker is a large detector with 112674 drift chamber channels. It is exposed to a particle flux of up to 2x10^5/cm^2/s thus coping with conditions similar to those expected for the LHC experiments. The front-end readout system, based on the ASD-8 chip and a customized TDC chip, is designed to fulfil the requirements on low noise, high sensitivity, rate tolerance, and high integration density. The TDC system is based on an ASIC which digitizes the time in bins of about 0.5 ns within a total of 256 bins. The chip also comprises a pipeline to store data from 128 events which is required for a deadtime-free trigger and data acquisition system. We report on the development, installation, and commissioning of the front-end electronics, including the grounding and noise suppression schemes, and discuss its performance in the HERA-B experiment

Discovery of the Binary Pulsar PSR B1259-63 in Very-High-Energy Gamma Rays around Periastron with H.E.S.S

We report the discovery of very-high-energy (VHE) gamma-ray emission of the binary system PSR B1259-63/SS 2883 of a radio pulsar orbiting a massive, luminous Be star in a highly eccentric orbit. The observations around the 2004 periastron passage of the pulsar were performed with the four 13 m Cherenkov telescopes of the H.E.S.S. experiment, recently installed in Namibia and in full operation since December 2003. Between February and June 2004, a gamma-ray signal from the binary system was detected with a total significance above 13 sigma. The flux was found to vary significantly on timescales of days which makes PSR B1259-63 the first variable galactic source of VHE gamma-rays observed so far. Strong emission signals were observed in pre- and post-periastron phases with a flux minimum around periastron, followed by a gradual flux decrease in the months after. The measured time-averaged energy spectrum above a mean threshold energy of 380 GeV can be fitted by a simple power law F_0(E/1 TeV)^-Gamma with a photon index Gamma = 2.7+-0.2_stat+-0.2_sys and flux normalisation F_0 = (1.3+-0.1_stat+-0.3_sys) 10^-12 TeV^-1 cm^-2 s^-1. This detection of VHE gamma-rays provides unambiguous evidence for particle acceleration to multi-TeV energies in the binary system. In combination with coeval observations of the X-ray synchrotron emission by the RXTE and INTEGRAL instruments, and assuming the VHE gamma-ray emission to be produced by the inverse Compton mechanism, the magnetic field strength can be directly estimated to be of the order of 1 G.Comment: 10 pages, 8 figures, accepted in Astronomy and Astrophysics on 2 June 2005, replace: document unchanged, replaced author field in astro-ph entry - authors are all members of the H.E.S.S. collaboration and three additional authors (99+3, see document