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Presents a new contact detection algorithm based on double‐ended spatial sorting (DESS) that is insensitive to variations in object size. It was developed to address the problems that arise when objects with non‐spherical geometry and non‐uniform sizes are simulated using discrete element techniques. The algorithm is applicable to general spatial reasoning problems. While techniques based on spatial hashing (sometimes called bining methods) perform well for objects of similar size, they degrade significantly when the objects vary in size. The DESS algorithm overcomes this problem by using a spatial sorting technique applied to both ends of the object’s projection along each orthogonal axis. Discrete element test simulations comparing DESS and spatial hashing (NBS) are detailed. The results demonstrate that when object sizes vary significantly (size ratios greater than 8:1), DESS outperforms NBS up to around 100,000 objects. It is noted, however, that the superior scaling properties of NBS will always outperform DESS for some large numbers of objects.

The purpose of this paper is to find a convenient contact detection algorithm in order to apply in distinct element simulation.

Taking the most computation effort, the performance of the contact detection algorithm highly affects the running time. The algorithms investigated in this study consist of Incremental Sort-and-Update (ISU) and Double-Ended Spatial Sorting (DESS). These algorithms are based on bounding boxes, which makes the algorithm independent of blocks shapes. ISU and DESS algorithms contain sorting and updating phases. To compare the algorithms, they were implemented in identical examples of rock engineering problems with varying parameters.

The results show that the ISU algorithm gives lower running time and shows better performance when blocks are unevenly distributed in both axes. The conventional ISU merges the sorting and updating phases in its naïve implementation. In this paper, a new computational technique is proposed based on parallelization in order to effectively improve the ISU algorithm and decrease the running time of numerical analysis in large-scale rock mass projects.

In this approach, the sorting and updating phases are separated by minor changes in the algorithm. This tends to a minimal overhead of running time and a little extra memory usage and then the parallelization of phases can be applied. On the other hand, the time consumed by the updating phase of ISU algorithm is about 30 percent of the total time, which makes the parallelization justifiable. Here, according to the results for the large-scale problems, this improved technique can increase the performance of the ISU algorithm up to 20 percent.

A critical step toward an efficient contact detection algorithm is to localize the contact search to the immediate neighborhood of each particle. In particular, cell‐based algorithms are simple and require O(N) computations but become inefficient when the particles are not roughly the same diameter. The purpose of this paper is to describe a hierarchical search method with the simplicity and efficiency of the neighbor search algorithm but which is insensitive to size gradation.

In this method, particles are allocated to cells based on their location and size within a nested hierarchical cell space. Contact searches are limited to neighboring particles of equal size within their own hierarchy and occasionally with particles of larger size when no contacts are found within their own hierarchy.

The method is shown to be effective for the most severe case of highly segregated particle distributions in which a large particle is surrounded by particles of much smaller size.

This paper is of value in concentrating on particular issues in implementing the hierarchical contact detection algorithm in a parallel computing environment using message‐passing interface.

Develop a new three‐dimensional discrete element code (BLOKS3D) for efficient simulation of polyhedral particles of any size. The paper describes efficient algorithms for the most important ingredients of a discrete element code.

New algorithms are presented for contact resolution and detection (including neighbor search and contact detection sections), contact point and force detection, and contact damping. In contact resolution and detection, a new neighbor search algorithm called TLS is described. Each contact is modeled with multiple contact points. A non‐linear force‐displacement relationship is suggested for contact force calculation and a dual‐criterion is employed for contact damping. The performance of the algorithm is compared to those currently available in the literature.

The algorithms are proven to significantly improve the analysis speed. A series of examples are presented to demonstrate and evaluate the performance of the proposed algorithms and the overall discrete element method (DEM) code.

Long computational times required to simulate large numbers of particles have been a major hindering factor in extensive application of DEM in many engineering applications. This paper describes an effort to enhance the available algorithms and further the engineering application of DEM.

The aim of this study was to first establish foundational algebraic expressions that parametrically describe any advanced dual-energy storage–propulsion–power system (DESPPS) and then proceed to declare the array of fundamental independent variables necessary for the sizing and optimisation of such systems. Upon procurement of a pre-design-level integrated aircraft performance model and the subsequent verification against previously published high-end low-fidelity generated results, opportunity was taken in formulating a set of battery-based DESPPS related design axioms and sizing heuristics.

Derivation of algebraic expressions related to describing DESPPS architectures are based on first principles. Integrated performance modelling by way of full analytical fractional change transformations anchored according to a previously published Energy Specific Air Range (ESAR) figure-of-merit originally derived using the Breguet–Coffin differential equation for vehicular efficiency. Weights prediction of sub-systems that constitute the entire aircraft including DESPPS constituents emphasises an analytical foundation with minimal implementation of linear correlation factors or coefficients of proportionality. An iterative maximum take-off weight build-up algorithm emphasising expedient and stable convergence was fashioned. All prediction methods pertaining to integrated performance were verified according to previously published battery-based DESPPS results utilising high-end low-fidelity methods.

For all types of DESPPS, two new fundamental independent non-dimensional variables were declared: the Supplied Power Ratio (related to converted power afforded by each energy carrier); and, the Activation Ratio (describing the relative nature of utilisation with respect to time afforded by the motive power device associated with each energy source). For a given set of standalone sub-system energy conversion efficiencies, the parametric descriptor of degree-of-hybridisation (DoH) for Power was found to be solely a function of the Supplied Power Ratio, whereas in contrast, the DoH for Energy was found to be a more complex synthetic function described by comingling of Supplied Power Ratio and the Activation Ratio. Upon examination of the integrated aircraft performance model derived in this treatise, for purposes of investigating CO₂-emissions reduction potential for battery-based DESPPS using kerosene as one of the energy sources, one salient observation was maximising the ESAR figure-of-merit is not an appropriate objective or intermediary function for future optimisation work. It was found maximising block fuel reduction through the use of maximum ESAR would lead to ever diminishing design ranges and curtailment of the payload-range working capacity of the aircraft.

Opportunity is now given to design and optimise aircraft utilising any type of DESPPS architecture. It was established that designing for battery-based DESPPS aircraft can be achieved effectively in a two-stage process that may not require aircraft morphologies more exotic than the so-called “wing-and-tube”. Firstly, a suitably projected state-of-the-art aircraft with solely advanced gas-turbine technology for the propulsion and power system needs to be produced. Thereafter, a revised version of this baseline projected aircraft now using DESPPS architecture should be conceived. A recommendation related to CO₂-emissions reduction potential for battery-based DESPPS using kerosene as one of the energy sources is that during optimisation work the multi-objective formulation should comprise at least two functions: block fuel and operating economics. In all instances, it was advised that the objective function of block fuel should be tempered by an equality constraint of ESAR parity with the baseline projected aircraft using gas-turbine only technology.

A complete, unified analytical description of DESPPS that is universally applicable to any type of energy carrier has been derived and verified for battery-based dual-energy systems. Correspondingly, a set of aircraft design axioms and sizing heuristics relevant to battery-based DESPPS have been presented.

The purpose of this paper is to analyse the processes of collecting used non-returnable packaging. The objective is to increase the quality and quantity of recycling material used in the production of new packages.

A reverse logistics network is proposed, nevertheless the focus of the study is addressing the collection routing problem. Specifically a new “profitable visit algorithm” (PVA) based on the well-known Nearest Neighbor is proposed and tested, in both real and simulated scenarios, in order to achieve higher volume of collected material while lowering the cost of collection.

The proposed algorithm is set to compete against the well-known Nearest Neighbor. The “PVA” showed a far better performance than the Nearest Neighbor. The latter was assessed with real data in a real scenario and was also confirmed by a simulation.

Further research should envisage stochastic models and tighter time constraints.

Managers can use the algorithm in similar scenarios to address different routing needs. New business activities could be foreseen by starting a logistics scheme of this type. Additionally, new savings in material procurement processes could be achieved in current operations.

Social responsibility and environmental awareness can be approached by this type of endeavors. While reducing waste disposal, the recovering of these materials yields savings and offer new labor opportunities for people.

The “PVA” introduced in this paper, showed substantial advantages. First it automatically determines the visit frequency for each client. Also, it evaluates whether a visit should be granted or not based on its “profitability.” The latter ensures that even if the routing circuit is broken at any moment, the company will not lose “profit.” Additionally, this research provides performance evaluation in real and simulated scenarios, which is hard to obtain in a single study.

 Reverse logistics, Recycling, Routing algorithm, Non-returnable packages, Real scenarios

 Research type

Objetivo

Este artículo analiza los procesos de recolección deenvases no retornable usados. El objetivo es aumentar la calidad y cantidad de material reciclable usado en la producción de nuevos envasados.

Se propone una red de logística reversa, no obstante el enfoque del estudio es abordar el problema de la ruta de recolección. Específicamente, se propone un nuevo “algoritmo de visita rentable” basado en el bien conocido Vecino Más Próximo y se testea en ambos escenarios reales y simulados, para poder lograr un volumen más alto de material recolectado y a su vez disminuir los costo de recolección.

El algoritmo propuesto está definido para competir contra el bien conocido Vecino Más próximo. El “algoritmo de visita rentable” mostro un rendimiento mucho mejor que el de Vecino Más próximo. Este último se evaluó con datos reales en un escenario real y también se confirmo a través de una simulación.

Investigaciones futuras deberían visualizar modelos estocásticos y restricciones de tiempo más limitadas.

Administradores pueden usar el algoritmo en escenarios similares para dirigir las diferentes necesidades de la ruta. Nuevas actividades de negocios podrían ser previstas iniciando un esquema logístico de este tipo. Adicionalmente, nuevos ahorros en procesos de material de adquisición podría ser logrado en las operaciones actuales.

La responsabilidad social y conciencia ambiental puede ser abarcado con este tipo de actividad. No sólo se reducen los residuos, pero también la recuperación de estos materiales genera ahorros y ofrece nuevas oportunidades de trabajo para las personas.

El “algoritmo visita rentable” introducido en este articulo, mostró ventajas substanciales. Primero, determina automáticamente la frecuencia de visitas para cada cliente. Además, evalúa si una visita basada en su “rentabilidad” debería ser dada o no. Esta última asegura que aunque el circuito de la ruta se quiebra en cualquier momento, la empresa no perderá “ganancias.” Adicionalmente, esta investigación provee evaluaciones de desempeño en escenarios reales y simulados, lo cual es difícil de obtener en un sólo estudio.

Trabajo de investigación

Objetivo

Este artigo analisa o processo de coletade embalagens não retornáveis usadas. O objetivo é aumentar a qualidade e as quantidades de materiais recicláveis utilizados na produção de novas embalagens.

Uma rede de logística reversa é proposta, embora o enfoque da pesquisa é abordar o problema da roteamento da coleta. Especificamente, um novo algoritmo de “Profitable Visit” baseado no conhecido Nearest Neighboré proposto Dois cenários são testados, um real e um simulado, com objetivos deatingimento de um volume maior de material coletado e também de diminuir os custos decoleta.

O algoritmo foi proposto para competir com o conhecido Nearest Neighbor. O algoritmo de “Profitable Visit” mostra um rendimento melhor que o Nearest Neighbor. Este último foi avaliado com dadosreais em um cenário real e também confirmado através de simulação.

Pesquisas futuras deveriam abordar modelos estocásticos e maiores restrições de tempo.

Gerentes podem utilizar o algoritmo em cenários similares para gerenciar diferentes necessidades de roteamento de coleta. Novos processos de negócios poderiam ser previstos com base em projetos logísticos deste tipo. Adicionalmente, ganhos adicionais em processos de compra de materiais poderiam ser obtidosem operações presentes.

A responsabilidade social e a consciência ambiental podem ser abordadas com este tipo de projeto. Junto com a eliminação de resíduos, a recuperação desses materiaistambém gera renda e oferece novas oportunidades de trabalho para as pessoas.

O algoritmo Profitable Visit” apresentadoneste artigo mostra vantagens substanciais. Primeiro, determina automaticamente a freqüência de visitas para cada cliente. Também, avalia se uma visita com base na “rentabilidade” deveria ocorrer ou não. Este aspecto assegura que quando o circuito da rota é modificado em qualquer momento, a empresa não perderá seus “ganhos.” Adicionalmente, esta pesquisa fornece avaliações de desempenho em cenários reais e simulados, o que é difícil de ocorrer em um único estudo.

Trabathos de pesquisa

This paper aims to propose an interpretive framework to understand how machine learning (ML) affects the way companies interact with their ecosystem and how the introduction of digital technologies affects the value co-creation (VCC) process.

This study bases on configuration theory, which entails two main methodological phases. In the first phase the authors define the theoretically-derived interpretive framework through a literature review. In the second phase the authors adopt a case study methodology to inductively analyze the theoretically-derived domains and their relationships within a configuration.

ML enables multi-directional knowledge flows among value co-creators and expands the scope of VCC beyond the boundaries of the firm-client relationship. However, it determines a substantive imbalance in knowledge management power among the actors involved in VCC. ML positively impacts value co-creators’ performance but also requires significant organizational changes. To benefit from VCC via ML, value co-creators must be aligned in terms of digital maturity.

The paper answers the call for more theoretical and empirical research on the impact of the introduction of Industry 4.0 technology in companies and their ecosystem. It intends to improve the understanding of how ML technology affects the determinants and the process of VCC by providing both a static and dynamic analysis of the topic.

Machine learning (ML) has recently gained momentum as a method for measurement in strategy research. Yet, little guidance exists regarding how to appropriately apply the method for this purpose in our discipline. We address this by offering a guide to the application of ML in strategy research, with a particular emphasis on data handling practices that should improve our ability to accurately measure our constructs of interest using ML techniques. We offer a brief overview of ML methodologies that can be used for measurement before describing key challenges that exist when applying those methods for this purpose in strategy research (i.e., sample sizes, data noise, and construct complexity). We then outline a theory-driven approach to help scholars overcome these challenges and improve data handling and the subsequent application of ML techniques in strategy research. We demonstrate the efficacy of our approach by applying it to create a linguistic measure of CEOs' motivational needs in a sample of S&P 500 firms. We conclude by describing steps scholars can take after creating ML-based measures to continue to improve the application of ML in strategy research.

This study considers the viability of the combination strategy with regard to the Porter and Miles & Snow generic strategy typologies. Within each framework, it is possible to pursue a “combination strategy,” whereby dimensions of two or more pure strategies are incorporated simultaneously. The present study presents findings from a recent assessment of perceptions of 415 American and Mexican managers regarding their firms’ strategies and levels of performance. Data suggests that combination strategies can be associated with either inferior or superior performance. This paper also suggests that additional research should considerre‐visit the I/O versus resource‐based schism and seek to integrate the two schools of thought into a broader consensus.

This study aims to examine the effect of entrepreneurial orientation (EO) on the export performance of apparel small- and medium-sized enterprises (SMEs) and the role of multiple differentiation strategy as a mediation effect between their relationships. It has also investigated the moderation impact of export market category between EO and performance relationship. The multiple differentiation strategy comprises the product (PDD), customer (CTD), service (SVD) and brand (BDD) differentiations.

A cross-sectional survey was carried out by providing a questionnaire to senior managers and owners of the apparel SMEs from the developed and developing markets exporters. The primary data of 550 was treated by the partial least squares-structural equation modelling) technique for final analysis.

The study revealed EO’s positive and significant effect on SMEs’ export performance. The study has found the mediation effect of product, customer and brand differentiation strategies between EO and export performance relationships from the mediation analysis. In contrast, service differentiation has found no mediation effect. However, the moderation effect (export market category) has revealed an insignificant effect between EO and performance association.

The findings of this study are based on one country data analysis. This study has been conducted in the SMEs of the apparel industry in Bangladesh, considering only owners and senior-level managers of the firms.

This research has drawn the attention of managers/owners to EO and multiple differentiation strategies enhancing export performance from the developing country context, such as Bangladesh. Multiple differentiation as a competitive strategy is the pioneer application of mediating effect between EO and export performance relationships. Moreover, this research has investigated the effect of the export market category as a moderator. Dearth research has applied the export market category to investigate the moderation effect between EO-performance models. Therefore, current research has theoretical and practical contributions to the international entrepreneurship and strategic management literature.