Refactorings of Design Defects using Relational Concept Analysis

Software engineers often need to identify and correct design defects, ıe} recurring design problems that hinder development and maintenance\ud by making programs harder to comprehend and--or evolve. While detection\ud of design defects is an actively researched area, their correction---mainly\ud a manual and time-consuming activity --- is yet to be extensively\ud investigated for automation. In this paper, we propose an automated\ud approach for suggesting defect-correcting refactorings using relational\ud concept analysis (RCA). The added value of RCA consists in exploiting\ud the links between formal objects which abound in a software re-engineering\ud context. We validated our approach on instances of the <span class='textit'></span>Blob\ud design defect taken from four different open-source programs

Swath Sounding Initiatives in Canada

Over the past 50 years, the hydrographic community has progressed from the humble leadline for single spot depths to sophisticated multibeam sounding systems capable of charting the entire seafloor. Canada now extensively uses this technology in its surveying operations. There are many benefits to using the latest swath systems, especially in the coastal margins and inland waters where, for instance, channel monitoring and dredging raise safety, economic and environmental issues. Utilizing multibeam systems reduces survey time, extends bottom coverage and contributes to conserving survey resources. Multibeam systems are expensive and the complexity of the system often requires high maintenance. In addition the software used for acquiring, processing and displaying the collected information is still maturing. Data cleaning algorithms to accommodate data collection rates that at times exceed 3000 data points per second are required. Canada has been dealing with those aspects of swath sounding for a decade now. Continuous research and development in the subject gave berth to new technologies and new acquisition and processing techniques. This paper summarizes the Canadian experiences in swath sounding and discusses its future developments and direction within the Canadian Hydrographic Service

Atmospheric neutron measurements with the SONTRAC science model

–The SOlar Neutron TRACking (SONTRAC) telescope was originally developed to measure the energy spectrum and incident direction of neutrons produced in solar flares, in the energy range 20 - 250 MeV. While developed primarily for solar physics, the SONTRAC detector may be employed in virtually any application requiring both energy measurement and imaging capabilities. The SONTRAC Science Model (SM) is presently being operated at the University of New Hampshire (UNH) as a ground-based instrument to investigate the energy spectrum, zenith and azimuth angle dependence of the cosmic-ray induced sea-level atmospheric neutron flux. SONTRAC measurements are based on the non-relativistic double scatter of neutrons off ambient protons within a block of scintillating fibers. Using the n-p elastic double-scatter technique, it is possible to uniquely determine the neutron’s energy and direction on an event-by-event basis. The 3D SM consists of a cube of orthogonal plastic scintillating fiber layers with 5 cm sides, read out by two CCD cameras. Two orthogonal imaging chains allow full 3D reconstruction of scattered proton tracks

Efficient Hole Trapping in Carbon Dot/Oxygen-Modified Carbon Nitride Heterojunction Photocatalysts for Enhanced Methanol Production from CO₂ under Neutral Conditions

Artificial photosynthesis of alcohols from CO 2 is a promising route to provide sustainable fuels. The performance is still unsatisfactory mainly due to the rapid charge relaxation compared to the sluggish photoreactions and the oxidation of alcohol products. Here, we demonstrate that CO 2 is reduced to methanol with 100% selectivity using water as the only electron donor on a carbon nitride-like polymer (FAT) decorated with carbon dots. The quantum efficiency of 5.9% (λ = 420 nm) is 300% higher than the previously reported carbon nitride junction. Using transient absorption spectroscopy, we observed that holes in FAT can be extracted by the carbon dots with nearly 75% efficiency before they become unreactive by trapping. Extraction of holes resulted in a greater density of photoelectrons, indicative of reduced recombination of shorter-lived reactive electrons. This work offers a unique strategy to promote photocatalysis by increasing the amount of reactive photogenerated charges via structure engineering and extraction before energy losses by deep trapping

An Incremental Learning Method to Support the Annotation of Workflows with Data-to-Data Relations

Workflow formalisations are often focused on the representation of a process with the primary objective to support execution. However, there are scenarios where what needs to be represented is the effect of the process on the data artefacts involved, for example when reasoning over the corresponding data policies. This can be achieved by annotating the workflow with the semantic relations that occur between these data artefacts. However, manually producing such annotations is difficult and time consuming. In this paper we introduce a method based on recommendations to support users in this task. Our approach is centred on an incremental rule association mining technique that allows to compensate the cold start problem due to the lack of a training set of annotated workflows. We discuss the implementation of a tool relying on this approach and how its application on an existing repository of workflows effectively enable the generation of such annotations

Developing conceptual hydrogeological model for Potsdam sandstones in southwestern Quebec, Canada

A hydrogeological study was conducted in Potsdam sandstones on the international border between Canada (Quebec) and the USA (New York). Two sandstone formations, arkose and conglomerate (base) and well-cemented quartz arenite (upper), underlie the study area and form the major regional aquifer unit. Glacial till, littoral sand and gravel, and marine silt and clay discontinuously overlie the aquifer. In both sandstone formations, sub-horizontal bedding planes are ubiquitous and display significant hydraulic conductivities that are orders of magnitude more permeable than the intact rock matrix. Aquifer tests demonstrate that the two formations have similar bulk hydrologic properties, with average hydraulic conductivities ranging from 2×10−5 to 4×10−5 m/s. However, due to their different lithologic and structural characteristics, these two sandstones impose rather different controls on groundwater flow patterns in the study area. Flow is sustained through two types of fracture networks: sub-horizontal, laterally extensive fractures in the basal sandstone, where hydraulic connectivity is very good horizontally but very poor vertically and each of the water-bearing bedding planes can be considered as a separate planar two-dimensional aquifer unit; and the more fractured and vertically jointed system found in the upper sandstone that promotes a more dispersed, three-dimensional movement of groundwater. Une étude hydrogéologique a été entreprise dans les grès de Potsdam, sur la frontière entre le Canada (Québec) et les Etats-Unis (New York). Sous le secteur d’étude, deux formations gréseuses, les arkoses et conglomérats (base) et les arénites quartzeuses cimentées (sommet), forment une unité aquifère majeure à l’échelle régionale. Les moraines glaciaires, les sables et graviers littoraux, et les argiles et silts marins recouvrent l’aquifère de manière discontinue. Dans les deux formations gréseuses, les litages sub-horizontaux sont omniprésents, et présentent des conductivités hydrauliques significatives, supérieures de plusieurs ordres de grandeur à celles de la matrice rocheuse intacte. Les pompages d’essai démontrent que les deux formations ont des propriétés hydrologiques apparentes comparables, avec notamment des conductivités hydrauliques comprises entre 2×10−5 et 4× 10−5 m/s. Cependant, du fait de leurs lithologies et de leurs caractéristiques structurales contrastées, ces deux formations gréseuses imposent des contrôles différents sur les écoulements souterrains dans le secteur d’étude. L’écoulement est soutenu par deux types de réseaux de fractures : des fractures latéralement extensives subhorizontales dans les grès de base, où la connectivité hydraulique est très bonne horizontalement mais médiocre verticalement, et où chacun des plans aquifères peut être considéré comme une unité aquifère isolée plane bidimensionnelle, et un système fissuré verticalement et plus fracturé situé dans les grès supérieurs, qui favorise des écoulements souterrains tridimensionnels et plus dispers

Distributed Formal Concept Analysis Algorithms Based on an Iterative MapReduce Framework

While many existing formal concept analysis algorithms are efficient, they are typically unsuitable for distributed implementation. Taking the MapReduce (MR) framework as our inspiration we introduce a distributed approach for performing formal concept mining. Our method has its novelty in that we use a light-weight MapReduce runtime called Twister which is better suited to iterative algorithms than recent distributed approaches. First, we describe the theoretical foundations underpinning our distributed formal concept analysis approach. Second, we provide a representative exemplar of how a classic centralized algorithm can be implemented in a distributed fashion using our methodology: we modify Ganter's classic algorithm by introducing a family of MR* algorithms, namely MRGanter and MRGanter+ where the prefix denotes the algorithm's lineage. To evaluate the factors that impact distributed algorithm performance, we compare our MR* algorithms with the state-of-the-art. Experiments conducted on real datasets demonstrate that MRGanter+ is efficient, scalable and an appealing algorithm for distributed problems.Comment: 17 pages, ICFCA 201, Formal Concept Analysis 201

Influence of topography on tide propagation and amplification in semi-enclosed basins

An idealized model for tide propagation and amplification in semi-enclosed rectangular basins is presented, accounting for depth differences by a combination of longitudinal and lateral topographic steps. The basin geometry is formed by several adjacent compartments of identical width, each having either a uniform depth or two depths separated by a transverse topographic step. The problem is forced by an incoming Kelvin wave at the open end, while allowing waves to radiate outward. The solution in each compartment is written as the superposition of (semi)-analytical wave solutions in an infinite channel, individually satisfying the depth-averaged linear shallow water equations on the f plane, including bottom friction. A collocation technique is employed to satisfy continuity of elevation and flux across the longitudinal topographic steps between the compartments. The model results show that the tidal wave in shallow parts displays slower propagation, enhanced dissipation and amplified amplitudes. This reveals a resonance mechanism, occurring when\ud the length of the shallow end is roughly an odd multiple of the quarter Kelvin wavelength. Alternatively, for sufficiently wide basins, also Poincaré waves may become resonant. A transverse step implies different wavelengths of the incoming and reflected Kelvin wave, leading to increased amplitudes in shallow regions and a shift of amphidromic points in the direction of the deeper part. Including the shallow parts near the basin’s closed end (thus capturing the Kelvin resonance mechanism) is essential to reproduce semi-diurnal and diurnal\ud tide observations in the Gulf of California, the Adriatic Sea and the Persian Gulf

Effect of heuristics on serendipity in path-based storytelling with linked data

Path-based storytelling with Linked Data on the Web provides users the ability to discover concepts in an entertaining and educational way. Given a query context, many state-of-the-art pathfinding approaches aim at telling a story that coincides with the user's expectations by investigating paths over Linked Data on the Web. By taking into account serendipity in storytelling, we aim at improving and tailoring existing approaches towards better fitting user expectations so that users are able to discover interesting knowledge without feeling unsure or even lost in the story facts. To this end, we propose to optimize the link estimation between - and the selection of facts in a story by increasing the consistency and relevancy of links between facts through additional domain delineation and refinement steps. In order to address multiple aspects of serendipity, we propose and investigate combinations of weights and heuristics in paths forming the essential building blocks for each story. Our experimental findings with stories based on DBpedia indicate the improvements when applying the optimized algorithm