5257 research outputs found
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Using genetic algorithms for order batching in multi-parallel-aisle picker-to-parts systems
No full textThis article aims to introduce a metaheuristic to solve the order batching problem in multi-parallel-aisle warehouse systems to minimise the travelled distance. The proposed metaheuristic is based on an item-oriented genetic algorithm (GA) using a new chromosome representation where a gen represents a customer order to guarantee feasibility in the mutation operator, decreasing the correction of chromosomes generated by the crossover operator, and avoiding the calculation of the minimum number of feasible batches. When comparing the performance of the proposed algorithm with the first-come-first-served (FCFS) rule in 360 instances, we found average savings of 11% (up to 24%) in travelled distance and 2% (up to 17%) in the number of batches. The proposed algorithm can be easily integrated into a warehouse management system (WMS) to provide significant savings in travelled distances, increasing the efficiency of order-picking operations, and reducing the consumption of energy sources required by picking devices. Copyright © 2020 Inderscience Enterprises Ltd
Cosmic-Ray Anisotropies in Right Ascension Measured by the Pierre Auger Observatory
No full textWe present measurements of the large-scale cosmic-ray (CR) anisotropies in R.A., using data collected by the surface detector array of the Pierre Auger Observatory over more than 14 yr. We determine the equatorial dipole component, through a Fourier analysis in R.A. that includes weights for each event so as to account for the main detector-induced systematic effects. For the energies at which the trigger efficiency of the array is small, the "east-west" method is employed. Besides using the data from the array with detectors separated by 1500 m, we also include data from the smaller but denser subarray of detectors with 750 m separation, which allows us to extend the analysis down to ∼0.03 EeV. The most significant equatorial dipole amplitude obtained is that in the cumulative bin above 8 EeV, %, which is inconsistent with isotropy at the 6σ level. In the bins below 8 EeV, we obtain 99% CL upper bounds on d ⊥ at the level of 1%-3%. At energies below 1 EeV, even though the amplitudes are not significant, the phases determined in most of the bins are not far from the R.A. of the Galactic center, at GC =-94°, suggesting a predominantly Galactic origin for anisotropies at these energies. The reconstructed dipole phases in the energy bins above 4 EeV point instead to R.A. that are almost opposite to the Galactic center one, indicative of an extragalactic CR origin. © 2020. The American Astronomical Society. All rights reserved.
Do sustainability practices influence university quality? A Colombian case study
No full textPurpose: This paper aims to know how university’s strategic managers, from botacademic and administrative systems, perceive the relationship between sustainability and accreditation as sustainability incorporation and the quality of their processes are amongst the actual challenges of universities. Design/methodology/approach: This paper opted for an inductive, exploratory study using the case study approach, including 19 in-depth interviews to administrative and academic managers in a private, high-quality certified university in Colombia. The data were assessed using the content analysis methodology. The Colombian accreditation guidelines were the base to analyse the data as accreditation is part of the quality assurance system. Findings: This paper provides empirical insights into how the implementation of sustainability in universities relates to the Colombian accreditation factors. The main links found were in the areas of the university’s social impact and organisational responsibility, which are highly relevant to graduates, external stakeholders and sustainability skills. Sustainable campus operation was associated with environmental management and improvement of the quality of the physical plant, with social and economic benefits in the long-term. Additionally, this research found a need for administrative and academic managers to understand and increase their commitment to sustainability. Research limitations/implications: Because it was a case study, results are not generalisable. Consequently, further research on similar lines is required to universalise the mentioned observation and results. Practical implications: The accreditation factors related to sustainability, inductively defined and exposed in this paper, provide an idea of how sustainability implementation could contribute to higher education quality assurance. Originality/value: This paper contributes to filling the knowledge gap about embedding sustainability in Latin-American universities. This paper postulates a starting point considering accreditation standards and the link of the strategic manager’s perceptions of sustainability. © 2020, Emerald Publishing Limited
Towards a digital transformation maturity model (DMTD) for credit unions [Hacia un modelo de madurez de transformación digital (MMTD) para las cooperativas de ahorro y crédito]
No full textThe formulation and implementation of a digital transformation strategy have become a key concern for many pre-digital organizations. Consequently, there is a fundamental need to support companies in the transition to the use of technologies and to guide them to improve their capabilities in a standardized, unbiased, and repeatable manner. The paper goal is presenting the first proposal for a Digital Transformation Maturity Model (DTMM) that meets the needs and challenges of the customer experience and is aligned with the characteristics of the credit unions. The methodology used is divided into six steps, starting with a systematic review of the literature on the subject, continuing with a semi-structured interview with experts in digital transformation, and then carrying out an information gathering with experts in the cooperative sector. All the above to validate the proposal of the dimensions and maturity levels associated with the MMTD. The results obtained are an MMTD structure for the cooperative sector with seven dimensions (1) Strategy, (2) Organization, (3) Customer, (4) Ecosystems, (5) Operations, (6) Technology, and (7) Innovation and their respective components. Also, five levels are proposed to evaluate the maturity of each dimension, Pioneers (Level 5), Optimized (Level 4), Integration (Level 3), Enablement (Level 2), Initiation (Level 1), and Not initiated (Level 0). © 2020, Associacao Iberica de Sistemas e Tecnologias de Informacao. All rights reserved
Solving the Order Batching Problem in Warehouses using Genetic Algorithms [Solución del Problema de Conformación de Lotes en Almacenes utilizando Algoritmos Genéticos]
No full textThis article aims to develop a genetic algorithm to minimize the distance traveled in warehouses and distribution centers where the order-batching problem applies for order picking systems. For this, a new representation of solutions is proposed, in which each gene of a chromosome represents a customer order to be retrieved, easing the application of crossover and mutation operators. Through computational experiments, it is shown that the genetic algorithm generates significant savings in distance traveled and number of batches compared to a basic rule of order batch formation, especially in scenarios where a greater number of batches is required. We conclude that the genetic algorithm provides efficient solutions in a reasonable computational time, thus its implementation is highly recommended in operative environments of warehouses and distribution centers. © Centro de Informacion Tecnologica. All rights reserved
Implications of a constitutional procedural codification in Colombia [Implicaciones de una codificación procesal constitucional para Colombia]
No full textThis paper analyses constitutional procedural law in Colombia. The existing debate regarding the codification of constitutional procedural law, along with its arguments for and against, is explained. It also studies the implications that this codification of constitutional procedural law may have on a State, specifically Colombia, regarding the reorganization of a constitutional jurisdic-tion, the role that judges must fulfill, the binding force of their decisions, and the relationship within the block of constitutionality and conventionality, pointing at the necessity to clearly design this codification upon the scope of those implications. © 2019, Universidad Nacional Autonoma de Mexico. All rights reserved
Analysis of 13 implementations of the software engineering management and engineering basic profile guide of ISO/IEC 29110 in very small entities using different life cycles
No full textWe are living in an age of growing demand for software products. This growing demand creates opportunities for very small entities (VSEs) to not only survive but also flourish. In this context, VSEs need to produce high-quality products to meet market needs. However, in their quest to produce high-quality software, VSEs need to overcome the challenge of implementing international standards, which they find difficult to do because of lack of knowledge and practical experience. This paper provides an analysis performed to 13 teams of VSEs, using different life cycles, which achieved the implementation of the ISO/IEC 29110, to analyze the effort each team invests to implement the best practices provided by the standard. Besides, the paper provides an analysis of the difficulties, and the benefits of using the six-step method are included. This analysis is of interest because software engineering knowledge developed by researchers should be transferred to the industry to reduce the gap between them. The results highlight, on the one hand, the practices representing more effort for teams by life cycle. On the other hand, the results highlight the six-step method that allowed the 13 teams to achieve a high level of coverage of the ISO/IEC 29110 international standard. © 2020 John Wiley & Sons, Ltd
Drivers of forest loss in a megadiverse hotspot on the pacific Coast of Colombia
No full textTropical forests are disappearing at unprecedented rates, but the drivers behind this transformation are not always clear. This limits the decision-making processes and the effectiveness of forest management policies. In this paper, we address the extent and drivers of deforestation of the Choco biodiversity hotspot, which has not received much scientific attention despite its high levels of plant diversity and endemism. The climate is characterized by persistent cloud cover which is a challenge for land cover mapping from optical satellite imagery. By using Google Earth Engine to select pixels with minimal cloud content and applying a random forest classifier to Landsat and Sentinel data, we produced a wall-to-wall land cover map, enabling a diagnosis of the status and drivers of forest loss in the region. Analyses of these new maps together with information from illicit crops and alluvial mining uncovered the pressure over intact forests. According to Global Forest Change (GFC) data, 2324 km2 were deforested in this area from 2001 to 2018, reaching a maximum in 2016 and 2017. We found that 68% of the area is covered by broadleaf forests (67,473 km2) and 15% by shrublands (14,483 km2), the latter with enormous potential to promote restoration projects. This paper provides a new insight into the conservation of this exceptional forest with a discussion of the drivers of forest loss, where illicit crops and alluvial mining were found to be responsible for 60% of forest loss. © 2020 by the authors
Environnmantal defenders in colombia, and the abductive deduction in the struggle to access to justice [Defensores ambientales en colombia y razonamiento abductivo en el acceso a la justicia]
No full textThe objective of this paper is to analyze the right to access to justice for environmental defenders in Colombia through abduction, a mode of inference discovered by Charles Sanders Peirce philosopher. Under a qualitative methodological approach, the data analysis technique is “Discursive Analysis” and applied to sources (Colombian status, international law, and official documents) it helps to construct the right definition of environmental defender. However, the 9th article of the Agreement of Escazu provides a structured definition that could help the lack of precision in legal definitions narrowly related to environmental defender in Colombian Law. This legal void reveal itself as a gap to defend protect those who protect the land and natural resources. To skip this obstacle it is necessary, first, to analyze the later developments in this subject matter as found in the Agreement of Escazu, and then it is also necessary to study an alternative type of logic. Finally, the conclusion is that, through abductive inference, 9th article interpretation by the judiciary can solve the struggle of environmental defenders’ in access to justice. © 2020 Editora Dom Helder. All rights reserved
Studies on the response of a water-Cherenkov detector of the Pierre Auger Observatory to atmospheric muons using an RPC hodoscope
No full textExtensive air showers, originating from ultra-high energy cosmic rays, have been successfully measured through the use of arrays of water-Cherenkov detectors (WCDs). Sophisticated analyses exploiting WCD data have made it possible to demonstrate that shower simulations, based on different hadronic-interaction models, cannot reproduce the observed number of muons at the ground. The accurate knowledge of the WCD response to muons is paramount in establishing the exact level of this discrepancy. In this work, we report on a study of the response of a WCD of the Pierre Auger Observatory to atmospheric muons performed with a hodoscope made of resistive plate chambers (RPCs), enabling us to select and reconstruct nearly 600 thousand single muon trajectories with zenith angles ranging from 0 to 55. Comparison of distributions of key observables between the hodoscope data and the predictions of dedicated simulations allows us to demonstrate the accuracy of the latter at a level of 2%. As the WCD calibration is based on its response to atmospheric muons, the hodoscope data are also exploited to show the long-term stability of the procedure. © 2020 IOP Publishing Ltd and Sissa Medialab