Requirements for a software maintenance support environment

This thesis surveys the field of software maintenance, and addresses the maintenance requirements of the Aerospace Industry, which is developing inige projects, running over many years, and sometimes safety critical in nature (e.g. ARIANE 5, HERMES, COLUMBUS). Some projects are collaborative between distributed European partners. The industry will have to cope in the near and far future with the maintenance of these products and it will be essential to improve the software maintenance process and the environments for maintenance. Cost effective software maintenance needs an efficient, high quality and homogeneous environment or Integrated Project Support Environment (IPSE). Most IPSE work has addressed software development, and lias not fully considered the requirements of software maintenance. The aim of this project is to draw up a set of priorities and requirements for a Maintenance IPSE. An IPSE, however can only support a software maintenance method. The first stage of this project is to deline 'software maintenance best practice' addressing the organisational, managerial and technical aspects, along with an evaluation of software maintenance tools for Aerospace systems. From this and an evaluation of current IPSEs, the requirements for a Software Maintenance Support Environment are presented for maintenance of Aerospace software

Time Series Forecasting: Obtaining Long Term Trends with Self-Organizing Maps

à la suite de la conférence ANNPR, Florence 2003International audienceKohonen self-organisation maps are a well know classification tool, commonly used in a wide variety of problems, but with limited applications in time series forecasting context. In this paper, we propose a forecasting method specifically designed for multi-dimensional long-term trends prediction, with a double application of the Kohonen algorithm. Practical applications of the method are also presented

Photoactivatable Fluorescent Tags for Dual-Modality Positron Emission Tomography Optical Imaging

Fluorescent protein conjugates are vital tools in a wide range of scientific disciplines from basic biochemical research to applications in clinical pathology and intraoperative surgery. We report the synthesis and characterization of photoactivatable fluorophores (PhotoTags) based on the functionalization of coumarin, fluorescein, BODIPY, rhodamine B, and cyanine dyes with a photochemically active aryl azide group. Photochemical labeling experiments using human serum albumin produced fluorescent proteins in high yields under irradiation with ultraviolet light for <15 min. We also synthesized DFO-RhodB-PEG3-ArN3─a photoactivatable compound that can be radiolabeled with 89Zr for applications in optical imaging and positron emission tomography. One-pot 89Zr-radiolabeling and light-induced protein conjugation produced [89Zr]ZrDFO-RhodB-PEG3-azepin-trastuzumab. Proof-of-concept studies in vitro and in vivo confirmed that [89Zr]ZrDFO-RhodB-PEG3-azepin-trastuzumab is a potential dual-modality agent for detecting human epidermal growth factor receptor 2 (HER2/neu) expression. Overall, the PhotoTag technology represents a rapid, synthetically versatile, and user-friendly approach for generating novel protein conjugates

De vermogensongelijkheid stijgt sinds de jaren tachtig

Piketty laat zien dat de curve van de vermogensongelijkheid in veel ontwikkelde landen een U-vorm kent: de ongelijkheid daalt vanaf de negentiende eeuw, en neemt vanaf het eind van de twintigste eeuw weer toe. Met een nieuwe methode kan aangetoond worden dat dit ook in Nederland geldt

De vermogensongelijkheid stijgt sinds de jaren tachtig

Piketty laat zien dat de curve van de vermogensongelijkheid in veel ontwikkelde landen een U-vorm kent: de ongelijkheid daalt vanaf de negentiende eeuw, en neemt vanaf het eind van de twintigste eeuw weer toe. Met een nieuwe methode kan aangetoond worden dat dit ook in Nederland geldt

De vermogensongelijkheid stijgt sinds de jaren tachtig

Piketty laat zien dat de curve van de vermogensongelijkheid in veel ontwikkelde landen een U-vorm kent: de ongelijkheid daalt vanaf de negentiende eeuw, en neemt vanaf het eind van de twintigste eeuw weer toe. Met een nieuwe methode kan aangetoond worden dat dit ook in Nederland geldt

Reachability in Dynamical Systems with Rounding

We consider reachability in dynamical systems with discrete linear updates, but with fixed digital precision, i.e., such that values of the system are rounded at each step. Given a matrix $M \in \mathbb{Q}^{d \times d}$, an initial vector $x\in\mathbb{Q}^{d}$, a granularity $g\in \mathbb{Q}_+$ and a rounding operation $[\cdot]$ projecting a vector of $\mathbb{Q}^{d}$ onto another vector whose every entry is a multiple of $g$, we are interested in the behaviour of the orbit $\mathcal{O}={}$, i.e., the trajectory of a linear dynamical system in which the state is rounded after each step. For arbitrary rounding functions with bounded effect, we show that the complexity of deciding point-to-point reachability---whether a given target $y \in\mathbb{Q}^{d}$ belongs to $\mathcal{O}$---is PSPACE-complete for hyperbolic systems (when no eigenvalue of $M$ has modulus one). We also establish decidability without any restrictions on eigenvalues for several natural classes of rounding functions.Comment: To appear at FSTTCS'2

Aquifer conditions, not irradiance determine the potential of photovoltaic energy for groundwater pumping across Africa

Groundwater pumping using photovoltaic energy has the potential to transform water services in poorly served areas. Here we develop a numerical model that uses openly available data to simulate the abstraction capacities of photovoltaic water pumping systems across Africa. The first contribution of this article is the detailed design of the large-scale model to include realistic geological constraints on the depth of pumping and sub-hourly irradiance time series. The second one is the provision of results for the whole continent. We simulated results for three system sizes (100, 1000, 3000 Wp) and the daily pumped volumes were found to vary between 0.1 and 180 m3, depending on the size and location. We show that, for much of Africa, groundwater pumping using photovoltaic energy is constrained by aquifer conditions, rather than irradiance. Our results can help identify regions where photovoltaic pumping has the highest potential and help target large scale investments

Charting the Chemical and Mechanistic Scope of Light-Triggered Protein Ligation

The creation of discrete, covalent bonds between a protein and a functional molecule like a drug, fluorophore, or radiolabeled complex is essential for making state-of-the-art tools that find applications in basic science and clinical medicine. Photochemistry offers a unique set of reactive groups that hold potential for the synthesis of protein conjugates. Previous studies have demonstrated that photoactivatable desferrioxamine B (DFO) derivatives featuring a para-substituted aryl azide ($ArN_3$) can be used to produce viable zirconium-89-radiolabeled monoclonal antibodies ($^{89}Zr-mAbs$) for applications in noninvasive diagnostic positron emission tomography (PET) imaging of cancers. Here, we report on the synthesis, $^{89}Zr$-radiochemistry, and light-triggered photoradiosynthesis of $^{89}Zr$-labeled human serum albumin (HSA) using a series of 14 different photoactivatable DFO derivatives. The photoactive groups explore a range of substituted, and isomeric $ArN_3$ reagents, as well as derivatives of benzophenone, a para-substituted trifluoromethyl phenyl diazirine, and a tetrazole species. For the compounds studied, efficient photochemical activation occurs inside the UVA-to-visible region of the electromagnetic spectrum (∼365–450 nm) and the photochemical reactions with HSA in water were complete within 15 min under ambient conditions. Under standardized experimental conditions, photoradiosynthesis with compounds 1–14 produced the corresponding $^{89}ZrDFO-PEG_{3}-HSA$ conjugates with decay-corrected isolated radiochemical yields between 18.1 ± 1.8% and 62.3 ± 3.6%. Extensive density functional theory (DFT) calculations were used to explore the reaction mechanisms and chemoselectivity of the light-induced bimolecular conjugation of compounds 1–14 to protein. The photoactivatable DFO-derivatives operate by at least five distinct mechanisms, each producing a different type of bioconjugate bond. Overall, the experimental and computational work presented here confirms that photochemistry is a viable option for making diverse, functionalized protein conjugates