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The purpose of this paper is to present a new and efficient technique for discrete element modelling using non-convex polyhedral grain shapes.

The efficiency of the technique follows from the use of grains that are dilated versions of the basic polyhedral grain shapes. Dilation of an arbitrary polyhedral grain is accomplished by placing the center of a sphere of fixed radius at every point on the surface. The dilated vertices become sphere segments and the edges become cylinder segments. The sharpness of the vertices and edges can be adjusted by varying the dilation radius. Contacts between two dilated polyhedral grains can be grouped into three categories; vertex on surface, vertex on edge, and edge on edge, or in the grammar of the model, sphere on polygonal surface, sphere on cylinder, and cylinder on cylinder. Simple, closed-form solutions exist for each of these cases.

The speed of the proposed polyhedral discrete element model is compared to similar models using spherical and ellipsoidal grains. The polyhedral code is found to run about 40 percent as fast as an equivalent code using spherical grains and about 80 percent as fast as an equivalent code using ellipsoidal grains. Finally, several applications of the polyhedral model are illustrated.

Few examples of discrete element modeling studies in the literature use polyhedral grains. This dearth is because of the perceived complexity of the polyhedral coding challenges and the slow speed of the codes compared to codes for other grain shapes. This paper presents a much simpler approach to discrete element modeling using polyhedral grain shapes.

The purpose of this paper is to classify body shapes using angular defects instead of sizes.

A large amount of dimensional data from a national anthropometry survey was analysed, and a basic pattern and its polyhedron were also used to create a three‐dimensional body shape from three body sizes. Using this method, the sizes were converted into nine angular defects.

The authors could define the factors explaining body shape characteristics and classify the body shapes into four groups. The four groups could be characterised by two pattern making difficulties of the upper and lower parts of the body as well as by two proportions, of waist girth to bust girth and bust girth to back length. Furthermore, depending on the age, the authors could understand body shape by the angle made.

Using a polyhedron model, the angles could be calculated using an enormous existing data set of sizes. An angular defect serves as an index to indicate the degree of difficulty for developing a flat pattern. If an angular defect of the bust is large, it is difficult to make a paper pattern of a bust dart. On the other hand, if an angular defect of the waist is large, it is easy to make a paper pattern of a waist dart. Thus, each body shape could be simultaneously characterized by two difficulty indices and two proportions of sizes.

This paper describes how non‐orthogonal geometric models may be transformed into orthogonal polyhedral models. The main purpose of the transformation is to obtain a geometric model that is easy to describe and further modify without loss of topological information from the original model.

The transformation method presented in this paper is based on fuzzy logic (FL). The idea of using FL for this type of transformation was first described by Takahashi and Shimizu. This paper describes both philosophy and techniques behind the transformation method as well as its application to some example 2D and 3D models. The problem in this paper is to define a transformation technique that will change a non‐orthogonal model into a similar orthogonal model. The orthogonal model is unknown at the start of the transformation and will only be specified once the transformation is complete. The model has to satisfy certain conditions, i.e. it should be orthogonal.

The group of non‐orthogonal models that contain triangular faces such as tetrahedra or pyramids cannot be successfully recognized using this method. This algorithm fails to transform these types of problem because to do so requires modification of the structure of the model. It appears that only when the edges are divided into pieces and the sharp angles are smoothed then the method can be successfully applied. Even though the method cannot be applied to all geometric models many successful examples for 2D and 3D transformation are presented. Orthogonal models with the same topology, which make them easier to describe, are obtained.

This transformation makes it possible to apply simple algorithms to orthogonal models enabling the solution of complex problems usually requiring non‐orthogonal models and more complex algorithms.

In recent years, there is a gradual shift from sequential computing to parallel computing. Nowadays, nearly all computers are of multicore processors. To exploit the available cores, parallel computing becomes necessary. It increases speed by processing huge amount of data in real time. The purpose of this paper is to parallelize a set of well-known programs using different techniques to determine best way to parallelize a program experimented.

A set of numeric algorithms are parallelized using hand parallelization using OpenMP and auto parallelization using Pluto tool.

The work discovers that few of the algorithms are well suited in auto parallelization using Pluto tool but many of the algorithms execute more efficiently using OpenMP hand parallelization.

The work provides an original work on parallelization using OpenMP programming paradigm and Pluto tool.

Flexible fixturing is an important aspect of any flexible manufacturing system (FMS) and computer integrated manufacturing (CIM) environment. The production analysis for fixturing within an FMS environment is presented. Various approaches to flexible fixturing are briefly described. The reconfigurable fixturing is one of the most appropriate flexible fixturing techniques for CIM environment. Reconfigurable and/or automated modular fixturing employs a number of fixture modules that are set up, adjusted and changed to form different fixture layout. The requirements for locating and constraining workpieces are presented. In addition, computer‐aided planning and analysis of fixture set up are discussed.

This study aims to structure a model for integrating social value into strategic management based on identifying the critical success factors (CSF) for such integration in the investigated companies.

This research was based on the actor–network theory. Through a rigorous approach to the case study methodology in a two-stage process lasting 21 months, we carried out this study.

Companies that use the polyhedral social accounting model in their strategic management processes do so without a reference model. We identified CSF for integrating social value, which was incorporated into a protocol model based on stakeholder theory and the use of social accounting.

Practitioners can use the proposed model to maintain the alignment of strategic performance and purpose. Using social accounting based on indicators and financial proxies allows managers to incorporate social value into strategic management in terms of financial value.

The institutional demand for social information is based on the growing sensitivity of companies. Aligning social values with business strategies contributes to social sustainability.

This study focuses on an unresearched emerging phenomenon. Since the first approach to stakeholder theory, the development of a stakeholder-oriented strategy has faced the lack of a stakeholder accounting system. The polyhedral model of social accounting could help overcome this problem as it provides information that allows a novel and innovative method to make a stakeholder-oriented strategy effective.

Most layer‐based rapid prototyping systems use polygonal models as input. In addition, the input polygonal models need to be manifold and water‐tight; otherwise the built objects may have defects or the building process may fail in some cases. This paper aims to present a regulation method of an arbitrarily complex polygonal model for rapid prototyping and manufacturing applications.

The method is based on a semi‐implicit representation of a solid model named the layered depth‐normal images (LDNI), which sparsely encodes the shape boundary of a polygonal model in three orthogonal directions. In the method, input polygonal models or parametric equations are first converted into LDNI models. A regulation operator based on the computed LDNI models is presented. A volume tiling technique is developed for very complex geometries and high accuracy requirements. From the processed LDNI model, an adaptive contouring method is presented to construct a cell representation that includes both uniform and octree cells. Finally, two‐manifold and water‐tight polygonal mesh surfaces are constructed from the cell representation.

The LDNI‐based mesh regulation operation can be robust due to its simplicity. The accuracy of the generated regulated models can be controlled by setting LDNI pixel width. Parallel computing techniques can be employed to accelerate the computation in the LDNI‐based method. Experimental results on various CAD models demonstrate the effectiveness and efficiency of our approach for complex geometries.

The input polygonal model is assumed to be closed in our method. The regulated polygonal model based on our method may have a big file size.

A novel mesh regulation method is presented in this paper. The method is suitable for rapid prototyping and manufacturing applications by achieving a balance between simplicity, robustness, accuracy, speed and scalability. This research contributes to the additive manufacturing development by providing a digital data preparation method and related tools.

Technology applied to learning is blurring the traditional outlines of the relations between publishing and technology industries, moving the internationalization strategy away from a gradual perspective toward accelerated internationalization. This paper aims to provide a conceptual model of polyhedral diagnosis of market entry strategy (PODMES model) for “born global” firms involved in e-learning industries.

The use of the case study methodology allowed apply PODMES model to a “born global” firm of the e-learning industry.

Results confirm that “born global” firms in the e-learning industry can adopt behaviors contrary to those expected in the literature. These behaviors imply new entry patterns by creating new strategic partner–supplier–client–competitor relations that extend the traditional analysis of the internal value chain to a process of value distribution through product and technology alliances.

This research provides two main contributions. First, an advance upon previous research into “born global” firms, through deep analysis of a case study that offers new findings regarding the phenomenon studied. It permits to align this research with previous analysis, following a strict case study methodology approach. Second, this study offers the application of a new methodology (PODMES model) that integrates the most relevant theories of internationalization (factorial dodecagon) within the five contingencies of entry market and the design of a strategic profile of internationalization.

This paper presents an offset‐based tool path generation method for STL format three‐dimensional (3D) models. The created tool‐paths can be effectively used to near‐net‐shaped parts, in particular those created using rapid prototyping.

The STL model is first offset by the distance of the selected cutter radius using a unique 3D offset method. The intersections between the top facing triangles of the offset model and tool‐path drive planes are calculated. The intersection line segments are sorted, trimmed and linked to generate continuous top envelope curves, which represent interference‐free tool paths.

The developed offset‐based algorithm can rapidly and successfully generate interference‐free tool paths as continuous lines, instead of a collection of discrete tool location points. The strategy of using adaptive step‐over distances based on local geometrical information can significantly increase machining efficiency.

The current tool path generation method only works for ball‐end mills. The entire surface of the STL model is treated as a single composite surface to be machined using raster milling. To improve machining efficiency, an automatic surface splitting algorithm could be developed to divide the model into several regions based on the characteristics of a group of triangular facets, and then machine these identified regions using different strategies and cutters.

The offset‐based tool‐path generation algorithm from STL models is a unique and novel development, which is useful in the rapid prototyping and computer‐aided machining areas.

Subtractive rapid prototyping (SRP) uses layer‐based removal from a plurality of orientations in order to create geometry in a highly automated manner. However, unlike additive means, the method can be inefficient due to redundant cutting operations on previously machined regions. The purpose of this paper is to present process planning methods for SRP, specifically dealing with stock material management in multiple setup operations.

Analysis of remaining stock material was performed by considering slices of respective stereolithography (STL) models. Further, an initial approximation was made of accessibility to enable iterative visibility analysis. The combination of these approaches led to efficient and fast algorithms. After analysis, the slices could be converted back to useful STL models through polyhedral reconstruction.

This method of approximation yields results similar to exact geometry. Using remaining stock data from this approach leads to a significant reduction in tool path length and processing time in SRP.

This paper presents novel methods of geometric representation and inaccessible volume calculation for four‐axis layer‐based machining and shows a successful implementation in an SRP system.