Entangled footprints: Understanding urban neighbourhoods by measuring distance,diversity, and direction of flows in Singapore

Traditional approaches to human mobility analysis in Geography often rely on census or survey data that is resource-intensive to collect and often has a limited spatio-temporal scope. The advent of new technologies (e.g. geosocial media platforms) provides opportunities to overcome these limitations and, if properly leveraged, can yield more granular insights about human mobility. In this paper, we use an anonymized Twitter dataset collected in Singapore from 2012 to 2016 to investigate this potential to help understand the footprints of urban neighbourhoods from both a spatial and a relational perspective.We construct home-to-destination networks of individual users based on their inferred home locations. In aggregated form, these networks allow us to analyze three specific mobility indicators at the neighbourhood level, namely the distance, diversity, and direction of urban interactions. By mapping these three indicators of the spatial footprint of each neighbourhood, we can capture the nuances in the position of individual neighbourhoods within the larger urban network. An exploratory spatial regression reveals that socio-economic characteristics (e.g. share of rental housing) and the built environment (i.e. land use) only partially explain these three indicators and a residual analysis points to the need to explicitly include each neighbourhood's position within the transportation network in future work.     

Virtual machining considering dimensional,geometrical and tool deflection errors in three-axis CNC milling machines

Virtual manufacturing systems can provide useful means for products to be manufactured without the need of physical testing on the shop floor. As a result, the time and cost of part production can be decreased. There are different error sources in machine tools such as tool deflection, geometrical deviations of moving axis and thermal distortions of machine tool structures. Some of these errors can be decreased by controlling the machining process and environmental parameters. However other errors like tool deflection and geometrical errors which have a big portion of the total error, need more attention. This paper presents a virtual machining system in order to enforce dimensional, geometrical and tool deflection errors in three-axis milling operations. The system receives 21 dimensional and geometrical errors of a machine tool and machining codes of a specific part as input. The output of the system is the modified codes which will produce actual machined part in the virtual environment.     

Frame-sliced voxel representation: An accurate and memory-efficient modeling method for workpiece geometry in machining simulation

This paper presents a new and enhanced voxel representation format for modeling the machined workpiece geometry in simulating machining operations involving repeated update of the workpiece model volume. The modeling format is named as the Frame-Sliced Voxel representation (FSV-rep) as it uses a novel concept of frame-sliced voxels to represent the boundary of the workpiece volume. The FSV-rep uses a multi-level surface voxel representation for sparse and memory-efficient implementations. The utilization of frame-sliced voxels enables approximation of the workpiece surface to only loosely depend on the grid resolution but achieve sub-voxel resolution updates for the model volume. It can, thus, provide a boundary representation of the workpiece model at an accuracy that is much higher than a basic voxel model of the same grid resolution and a similar model size. Quantitative comparisons of the FSV-rep with the traditional voxel representations at the same finest grid resolution show improvement up to two orders of magnitude in accuracy with only marginal increases in the model size. This confirms the effectiveness of the FSV-rep in simulating machined workpiece geometry in complex machining processes such as multi-axis milling.     

Eigenspace compression: dynamic 3D mesh compression by restoring fine geometry to deformed coarse models

Multimedia Tools and Applications - Dynamic 3D mesh compression is of great practical important issues in computer graphics and multimedia applications. In this paper, an efficient compression...     

Photo-electroforming: 3-D geometry and materials flexibility in aMEMS fabrication process

Photo-electroforming is a new manufacturing process for making microelectromechanical systems (MEMS). Photo-electroforming builds parts by an additive process which defines geometry by depositing powder in layers and creating regions of selective conductivity by laser-enhanced electroless plating. The conductive region is then joined by a second plating to form an integral part. The unmetallized portion is removed by selective etching in one step after all layers are defined and joined. Single-layer and two-layer stand-alone parts made of nickel/silicon carbide composites of overall size 75-100 μm and feature size 25 μm were created. Writing speeds of up to 24 cm/s and in-plane resolution of 15 μm were demonstrated. The high laser-induced plating rates were found to be due to elevated substrate temperatures under the laser spot and enhanced mass transfer due to pumping by the hydrogen bubbles resulting from the plating reaction. In the regimes studied, mass transfer defined the rate limit. The in-plane resolution was found to be limited by a combination of laser spot size, thermal conduction in the substrate, and laser divergence due to gas bubbles     

三维软件在大运量、长距离输煤管道设计中的应用

针对采用二维软件进行工艺管道布置存在的工作量大、易出错等问题,分析了国内设计领域所使用的各种三维软件的优缺点,并提出将Solidworks软件应用于大运量、长距离输煤管道设计中,详细介绍了Solidworks软件在输煤管道方案设计阶段、初步设计阶段、施工图设计阶段中的应用。     

From on-line sketching to 2D and 3D geometry: a system based on fuzzy knowledge

The paper describes the development of a fuzzy knowledge-based prototype system for conceptual design. This real time system is designed to infer user's sketching intentions, to segment sketched input and generate corresponding geometric primitives: straight lines, circles; arcs, ellipses, elliptical arcs, and B-spline curves. Topology information (connectivity, unitary constraints and pairwise constraints) is received dynamically from 2D sketched input and primitives. From the 2D topology information, a more accurate 2D geometry can be built up by applying a 2D geometric constraint solver. Subsequently, 3D geometry can be received feature by feature incrementally. Each feature can be recognised by inference knowledge in terms of matching its 2D primitive configurations and connection relationships. The system accepts not only sketched input, working as an automatic design tool, but also accepts user interactive input of both 2D primitives and special positional 3D primitives. This makes it easy and friendly to use. The system has been tested with a number of sketched inputs of 2D and 3D geometry.     

The future threat to computers and composition: Nontenured instructors, intellectual property, and distance education

In this article, I argue that recent initiatives concerning the use of computer-mediated instruction to improve writing skills in large lecture classes often work to undermine the professional status of composition teachers in North American universities. I trace the use of computer-assisted instruction, specifically distance-education initiatives. To further the cause of a just implementation of CAI, I discuss recent contractual language and explore the current practice of hiring computers and writing specialists into nontenurable staff positions. I posit that writing program administrators need to fight for stable, long-term positions for faculty who teach with computers and within computer-mediated spaces. I also argue that compositionists must seek to regulate and control the ownership of their intellectual property and course materials.     

Study of the solubility of Pb,Bi and Sn in aluminum by mixed CALPHAD/DFT methods: Applicability to aluminum machining alloys

The aim of this work is a formulation of a thermodynamic model for the development of new aluminum machining alloys. The three additives Bi, Pb and Sn have proven to help machining. Hence, a review of the literature showed that the liquid phase equilibria and thermodynamic data for the three binary systems Al-Bi, Al-Pb and Al-Sn is very thorough but the limited information for the FCC solution required the use of Density Functional Theory (DFT) to predict thermodynamic data. The partial heat of mixing of these three machining additives in Al(FCC) are obtained and the results helped to improve the thermodynamic model using the CALPHAD method. It was shown that for all three binary systems, the thermodynamic data obtained at three fixed compositions and that obtained for a very dilute solution gave different enthalpy curves. The thermodynamic model was used to compute the ternary systems Al-Bi-Pb, Al-Bi-Sn and Al-Pb-Sn and small adjustable parameters were added to reproduce the literature data.     

Predicting the distance between antibody’s interface residue and antigen to recognize antigen types by support vector machine

In this paper, a machine learning approach, known as support vector machine (SVM) is employed to predict the distance between antibody’s interface residue and antigen in antigen–antibody complex. The heavy chains, light chains and the corresponding antigens of 37 antibodies are extracted from the antibody–antigen complexes in protein data bank. According to different distance ranges, sequence patch sizes and antigen classes, a number of computational experiments are conducted to describe the distance between antibody’s interface residue and antigen with antibody sequence information. The high prediction accuracy of both self-consistent and cross-validation tests indicates that the sequential discovered information from antibody structure characterizes much in predicting the distance between antibody’s interface residue and antigen. Furthermore, the antigen class is predicted from residue composition information that belongs to different distance range by SVM, which shows some potential significance.     

Toward AI-enabled augmented reality to enhance the safety of highway work zones: Feasibility,requirements, and challenges

Highway work zones are considered among the most hazardous working environments. In 2018 alone, 124 workers lost their lives to fatal accidents. The lack of predictive safety systems that notify workers of upcoming dangers in advance is a major reason to blame in the highway maintenance and operation community. This article presents an integrative design framework for bringing recent advances in Augmented Reality (AR) and Artificial Intelligence (AI) to enhance the safety of highway workers through real-time multimodal notifications on-spot. To this end, this article conceptualizes and co-designs three major pillars: (1) AR user interface design for multimodal notification, (2) real-time AI at the edge for vehicle detection/classification from distance, and (3) real-time wireless communication in work zone setting to enable latency-aware operation between AI and AR components. Our early results demonstrate that we can achieve 24.83 FPS end-to-end execution latency on the Xavier AGX Jetson board with 48.7% mAP on BDD100K dataset, and a real-time communication covering 120 meters with an average latency of 5.1 ms at the farthest distance. Our mixed-method user research also reveals an acceptable level of excitement and engagement from the body of highway workers toward both the proposed technology and the designed user interface. Overall, this article provides a proof-of-concept toward AI-enabled AR safety systems in highway work zones.     

Spatial relations between 3D objects: The association between natural language,topology, and metrics

With the proliferation of 3D image data comes the need for advances in automated spatial reasoning. One specific challenge is the need for a practical mapping between spatial reasoning and human cognition, where human cognition is expressed through natural-language terminology. With respect to human understanding, researchers have found that errors about spatial relations typically tend to be metric rather than topological; that is, errors tend to be made with respect to quantitative differences in spatial features. However, topology alone has been found to be insufficient for conveying spatial knowledge in natural-language communication. Based on previous work that has been done to define metrics for two lines and a line and a 2D region in order to facilitate a mapping to natural-language terminology, herein we define metrics appropriate for 3D regions. These metrics extend the notions of previously defined terms such as splitting, closeness, and approximate alongness. The association between this collection of metrics, 3D connectivity relations, and several English-language spatial terms was tested in a human subject study. As spatial queries tend to be in natural language, this study provides preliminary insight into how 3D topological relations and metrics correlate in distinguishing natural-language terms.     

Relationships between topographically expressed zones of flow accumulation and sites of fault intersection: analysis by means of digital terrain modelling

Topographically expressed zones of flow accumulation often coincide with fault intersections because of increased rock fracturing. We have conducted a study of the interrelationships between topographically expressed accumulation zones and fault intersections, and the function of these sites in landscape evolution. The investigation has been performed with the use of digital terrain models, geological and soil data for the Crimean Peninsula. First, we carried out an analysis of associations of sites of fault intersections, intensive rock fracturing and abnormally high discharges of springs and boreholes, relating to fault intersections, with three types of landform element (zones of flow accumulation, transit and dissipation). We found that all phenomena under study are closely associated with topographically expressed accumulation zones. This has demonstrated that, within these zones, the soil moisture is influenced both by upward transport of deep-seated groundwater and by accumulation of overland lateral flows. Second, we predicted the effect of topography on irrigation-induced changes in the salt regime of soils and the groundwater level, assuming that topographically expressed accumulation zones can be marked by properties of fault intersections. We found that water leaking out of the North Crimean Canal can result in secondary salinisation of soils and a considerable rise of the watertable within some accumulation zones located downslope. Salts collected in the accumulation zones, and their slow movement through rock fractures, can lead to salinisation of the aquifers. We believe that topographically expressed accumulation zones are areas of contact and substance exchange between overland lateral and deep flows.     

The price of free software: Labor, ethics, and context in distance education

The use, development, and dissemination of open-source software (OSS) appears to be more in line with the liberatory, collaborative, epistemological ideals of institutions of higher learning than does commercial software. However, our primary and secondary research reveals that due largely to institutional pressures and labor issues, open source software options are often not explored or considered when teaching distance-learning writing courses. In this article, we compare open source and commercial content/course management options and demonstrate the benefits and problems of specific applications. Additionally, we discuss our results from case studies of four instructors who teach distance-learning writing courses. We detail what types of applications they use, the level of institutional support they receive, and the motivations for their choices of applications.     

Variation in spectral response of soybeans with respect to illumination,view and canopy geometry

Comparisons of the spectral response for incomplete (well-defined row structure) and complete (overlapping row structure) canopies indicated that there was a greater dependence on Sun and view geometry for the incomplete canopies. This effect was more pronounced for the highly absorptive red (0.6-0.7 μm) wavelength band than for the near-infrared (IR) (0.8-1.1 μm) based on relative reflectance factor changes.

Red and near-IR reflectance for the incomplete canopy decreased as solar zenith angle increased for a nadir view angle until the soil between the plant rows was completely shaded. Thereafter for increasing solar zenith angle the red reflectance levelled off and the near-IR reflectance increased. A ‘hot-spot’ effect was evident for the red and near-IR reflectance factors, especially when the Sun-sensor view directions were perpendicular to the rows. The ‘hot-spot’ effect was more pronounced for the red band based on relative reflectance value changes. The effect of Sun angle was more pronounced for view angles perpendicular to the row direction.

An analysis of the ratios of off-nadir- to nadir-acquired data revealed that off-nadir red band reflectance factors more closely approximated straight-down measurements for time periods away from solar noon. Near-IR and greenness responses showed a similar behaviour. Normalized difference generally approximated straight-down measurements during the middle portion of the day. An exception occurred near solar noon when sunlit bare soil was present in the scene.     

RETRACTED ARTICLE: Correlation between Amount-of-Reuse Metrics and Other Software Measures with Respect to Programming Code in C++

In recent years, there have been several proposals for amount-of-reuse metrics. However, it is not clear if these metrics measure anything different from other software metrics that are often generally used. Besides, the relationship between these metrics is also unclear. Without a clear understanding, the true added value provided by these metrics remains unknown. In this paper, an analysis of the existing amount-of-reuse metrics is presented and a subset of these is selected, on the basis of their industrial applicability, for further investigation. These metrics are then applied to a collection of different software products to obtain an understanding of the level of correlation that exists between them and other well-known software metrics such as cyclomatic complexity, volume and lines of code. Our analysis suggests that the selected subset of amount-of-reuse metrics provides a relatively independent view of the analyzed code.