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Smart cities and communities (SCC) constitute a new paradigm in urban development. SCC ideate a data-centered society aimed at improving efficiency by automating and optimizing activities and utilities. Information and communication technology along with Internet of Things enables data collection and with the help of artificial intelligence (AI) situation awareness can be obtained to feed the SCC actors with enriched knowledge. This paper describes AI perspectives in SCC and gives an overview of AI-based technologies used in traffic to enable road vehicle automation and smart traffic control. Perception, smart traffic control and driver modeling are described along with open research challenges and standardization to help introduce advanced driver assistance systems and automated vehicle functionality in traffic. To fully realize the potential of SCC, to create a holistic view on a city level, availability of data from different stakeholders is necessary. Further, though AI technologies provide accurate predictions and classifications, there is an ambiguity regarding the correctness of their outputs. This can make it difficult for the human operator to trust the system. Today there are no methods that can be used to match function requirements with the level of detail in data annotation in order to train an accurate model. Another challenge related to trust is explainability: models can have difficulty explaining how they came to certain conclusions, so it is difficult for humans to trust them.

The efficiency of 133Ba and 137Cs removal from aqueous solution is vital to mitigate ecological concerns over spreading these radionuclides in the environment. The present work focused on the use of Turkish perlite for the sorptive removal of 133Ba and 137Cs from aqueous solution by the radioindicator method. Perlite was characterized by XRF, XRD, FTIR, SEM–EDX, and BET analyses. The maximum percentage removals of 88.2% and 78.7% were obtained for 133Ba and 137Cs at pH 6 and pH 9, respectively. For both ions, the sorption equilibrium was attained relatively rapidly. Experimental kinetic data were well described with pseudo-second-order and intraparticle diffusion models. The uptake of both ions increased with the increase in metal concentration (1 × 10−5 to 5 × 10−2 mol/L) in solution. The maximum uptake capacities of 133Ba and 137Cs were found to be 1.96 and 2.11 mmol/g, respectively. The effect of competing ions decreased in the order of Ca2+>K+>Ni2+>Na+ for 133Ba sorption, whereas for 137Cs sorption, the order was determined as Ca2+>Ni2+>K+>Na+. Selectivity studies pointed out that sorption of 133Ba onto perlite is preferable to 137Cs. Therefore, Turkish perlite is a promising, cost-effective, and efficient natural material for the removal of 133Ba and 137Cs from relatively diluted aqueous solution.

Statistical power analyses are used in the design of experiments to determine the required number of specimens, and thus the expenditure, of a test. Commonly, when analyzing and planning life tests of technical products, only the confidence level is taken into account for assessing uncertainty. However, due to the sampling error, the confidence interval estimation varies from test to test; therefore, the number of specimens needed to yield a successful reliability demonstration cannot be derived by this. In this paper, a procedure is presented that facilitates the integration of statistical power analysis into reliability demonstration test planning. The Probability of Test Success is introduced as a metric in order to place the statistical power in the context of life test planning of technical products. It contains the information concerning the probability that a life test is capable of demonstrating a required lifetime, reliability, and confidence. In turn, it enables the assessment and comparison of various life test types, such as success run, non-censored, and censored life tests. The main results are four calculation methods for the Probability of Test Success for various test scenarios: a general method which is capable of dealing with all possible scenarios, a calculation method mimicking the actual test procedure, and two analytic approaches for failure-free and failure-based tests which make use of the central limit theorem and asymptotic properties of several statistics, and therefore simplify the effort involved in planning life tests. The calculation methods are compared and their respective advantages and disadvantages worked out; furthermore, the scenarios in which each method is to be preferred are illustrated. The applicability of the developed procedure for planning reliability demonstration tests using the Probability of Test Success is additionally illustrated by a case study.

This paper presents a framework that tackles the challenges met in the development of automation systems featuring collaborative robotics and other machines that have some degree of autonomy. These machines rely on online algorithms for both sensing and acting in order to achieve a very high level of flexibility. To take advantage of these new machines and algorithms, control systems must also be increasingly flexible. In this paper, we present a framework for control of this new class of intelligent automation systems called Sequence Planner (SP), which helps with control of both traditional automation equipment and machines with autonomy. To aid the complex task of developing automation control solutions, SP relies on supporting algorithms for control logic synthesis and online planning. SP has been implemented with plug-in support for the Robot Operating System (ROS) and applied to an industrial demonstrator. We present our findings on how SP performed as a control system for this demonstrator, where we show that it is an adequate approach to implement automation for a highly flexible single station system. As a standardized way of automating such systems is missing, we hope that our contribution will provide a foundation for how to develop intelligent automation systems.

In this work, a new method for selecting suitable materials is presented. This method has a high potential for a variety of engineering applications, such as the design of sound-absorbing and vibration-loaded structures, where a large number of different requirements have to be met. The method is based on the derivation of functional dependencies of selected material parameters. These dependencies can be used in parameter studies to consider parameter combinations that lie in the range of real existing and targeted material groups. This allows the parameter space to be reduced, the calculation to be accelerated, and suitable materials to be (pre-)selected for the respective application, which contributes to a more target-oriented design. The method is applied to the example of a plate resonator. For this purpose, a semi-analytical model is implemented to calculate the transmission loss as well as the reflected and dissipated sound power of plate silencers, taking into account the influence of flow velocity and fluid temperature on the performance of plate silencers.

The removal of bacterial infections within the root canal system is still a challenge. Therefore, the cleansing effect of established and new irrigation-protocols (IP) containing silver diamine fluoride (SDF) 3.8% on the whole root canal system was analyzed using quantitative PCR (qPCR) and 4′,6-diamidino-phenylindole-(DAPI)-staining. Extracted human premolars were instrumented up to F2 (ProTaper Gold) under NaCl 0.9% irrigation and incubated with Enterococcus faecalis for 42 days. Subsequently, different ultrasonically agitated IP were applied to the roots: control (no irrigation), 1. NaOCl 3%, EDTA 20%, CHX 2%, 2. NaOCl 3%, EDTA 20%, 3. NaOCl 3%, EDTA 20%, SDF 3.8%, 4. SDF 3.8%, and 5. NaCl 0.9%. One half of the root was investigated fluorescent-microscopically with DAPI. The other half was grinded in a cryogenic mill and the bacterial DNA was quantified with qPCR. The qPCR results showed a statistically significant reduction of bacteria after the application of IP 1, 2, and 3 compared to the control group. While IP 4 lead to a bacterial reduction which was not significant, IP 5 showed no reduction. These data corresponded with DAPI staining. With qPCR a new molecular-biological method for the investigation of the complete root canal system was implemented. The novel IP 3 had an equally good cleansing effect as the already established IP.

Con el advenimiento de mercados globalizados donde aumentan los desperdicios derivados de procesos productivos y ante la evidente necesidad de adoptar medidas que disminuyan los impactos negativos asociados a su disposición final, la formulación de sistemas de logística inversa a medida de las empresas que permitan realizar una disposición responsable de los residuos maximizando la obtención de valor de estos ha sido objeto de estudio en los últimos años. El objetivo de este artículo es proponer un Sistema de Logística Inversa para un astillero que se enfoque en los residuos derivados de las operaciones de mantenimiento realizadas a embarcaciones bajo un enfoque sostenible. La metodología se basó en un análisis de la literatura científica en términos de logística inversa y sostenibilidad, al igual que la caracterización de los procesos en las instalaciones del astillero, desarrollando estrategias que soporten la implementación del sistema propuesto e indicadores que controlen su futura implementación.

Wire arc additive manufacturing (WAAM) is a direct energy deposition (DED) process with high deposition rates, but deformation and distortion can occur due to the high energy input and resulting strains. Despite great efforts, the prediction of distortion and resulting geometry in additive manufacturing processes using WAAM remains challenging. In this work, an artificial neural network (ANN) is established to predict welding distortion and geometric accuracy for multilayer WAAM structures. For demonstration purposes, the ANN creation process is presented on a smaller scale for multilayer beads on plate welds on a thin substrate sheet. Multiple concepts for the creation of ANNs and the handling of outliers are developed, implemented, and compared. Good results have been achieved by applying an enhanced ANN using deformation and geometry from the previously deposited layer. With further adaptions to this method, a prediction of additive welded structures, geometries, and shapes in defined segments is conceivable, which would enable a multitude of applications for ANNs in the WAAM-Process, especially for applications closer to industrial use cases. It would be feasible to use them as preparatory measures for multi-segmented structures as well as an application during the welding process to continuously adapt parameters for a higher resulting component quality.

We report on the pilot scale synthesis and melt spinning of poly(ethylene furanoate) (PEF), a promising bio-based fiber polymer that can heave mechanical properties in the range of commercial poly(ethylene terephthalate) (PET) fibers. Catalyst optimization and solid state polycondensation (SSP) allowed for intrinsic viscosities of PEF of up to 0.85 dL·g−1. Melt-spun multifilament yarns reached a tensile strength of up to 65 cN·tex−1 with an elongation of 6% and a modulus of 1370 cN·tex−1. The crystallization behavior of PEF was investigated by differential scanning calorimetry (DSC) and XRD after each process step, i.e., after polymerization, SSP, melt spinning, drawing, and recycling. After SSP, the previously amorphous polymer showed a crystallinity of 47%, which was in accordance with literature. The corresponding XRD diffractograms showed signals attributable to α-PEF. Additional, clearly assignable signals at 2θ > 30° are discussed. A completely amorphous structure was observed by XRD for as-spun yarns, while a crystalline phase was detected on drawn yarns; however, it was less pronounced than for the granules and independent of the winding speed.

Growing concern over the hazardous effect of radionuclides on the environment is driving research on mitigation and deposition strategies for radioactive waste management. Currently, there are many techniques used for radionuclides separation from the environment such as ion exchange, solvent extraction, chemical precipitation and adsorption. Adsorbents are the leading area of research and many useful materials are being discovered in this category of radionuclide ion separation. The adsorption technologies lack the ability of selective removal of metal ions from solution. This drawback is eliminated by the use of ion-imprinted polymers, these materials having targeted binding sites for specific ions in the media. In this review article, we present recently published literature about the use of ion-imprinted polymers for the adsorption of 10 important hazardous radionuclides—U, Th, Cs, Sr, Ce, Tc, La, Cr, Ni, Co—found in the nuclear fuel cycle.

The work deals with the evaluation of biochar samples prepared from Phyllostachys Viridiglaucescens bamboo. This evaluation consists of the characterization of prepared materials’ structural properties, batch and dynamic sorption experiments, and potentiometric titrations. The batch technique was focused on obtaining basic sorption data of 99mTcO4− on biochar samples including influence of pH, contact time, and Freundlich isotherm. ReO4−, which has very similar chemical properties to 99mTcO4−, was used as a carrier in the experiments. Theoretical modeling of titration curves of biochar samples was based on the application of surface complexation models, namely, so called Chemical Equilibrium Model (CEM) and Ion Exchange Model (IExM). In this case it is assumed that there are two types of surface groups, namely, the so-called layer and edge sites. The dynamic experimental data of sorption curves were fitted by a model based on complementary error function erfc(x).

The extensive knowledge of root dentin’s mechanical properties is necessary for the prediction of microstructural alterations and the teeth’s deformations as well as their fracture behavior. Standardized microindentation tests were applied to apical, medial, and cervical root sections of a mandibular human first molar to determine the spatial distribution of the hard tissue’s properties (indentation modulus, indentation hardness, Martens hardness, indentation creep). Using an indentation mapping approach, the inhomogeneity of mechanical properties in longitudinal as well as in transversal directions were measured. As a result, the tooth showed strongly inhomogeneous material properties, which depended on the longitudinal and transversal positions. In the transversal cutting planes of the cervical, medial, apical sections, the properties showed a comparable distribution. A statistical evaluation revealed an indentation modulus between 12.2 GPa and 17.8 GPa, indentation hardness between 0.4 GPa and 0.64 GPa and an indentation creep between 8.6% and 10.7%. The established standardized method is a starting point for further investigations concerning the intensive description of the inhomogeneous mechanical properties of human dentin and other types of dentin.

Este artículo presenta la aplicación de la metodología Kanban y el análisis del efecto que puede generar en una empresa de fabricación de transformadores de distribución. Mediante la aplicación de la metodología propuesta es posible mejorar la programación de la producción, con el objetivo de reducir la cantidad de producto en proceso que no es utilizado, de forma que se reduzca el inventario. Para analizar el efecto de aplicar la metodología Kanban en la empresa, se utilizo la técnica de simulación, para lo cual se modelizan el proceso actual y el propuesto con las reglas de dicha metodología. A partir de los resultados que arrojan dichas modelizaciones, se observa que existe un mejoramiento en las líneas de producción cuando se utiliza la metodología Kanban.

Compressible Constrained Layer Damping (CCLD) is a novel, semi-active, lightweight-compatible solution for vibration mitigation based on the well-known constrained layer damping principle. The sandwich-like CCLD set-up consists of a base structure, a constraining plate, and a compressible open-cell foam core in between, enabling the adjustment of the structure’s vibration behaviour by changing the core compression using different actuation pressures. The aim of the contribution is to show to what degree, and in which frequency range the acoustic behaviour can be tuned using CCLD. Therefore, the sound transmission loss (TL), as an important vibro-acoustic index, is determined in an acoustic window test stand at different actuation pressures covering a frequency range from 0.5 to 5 kHz. The different actuation pressures applied cause a variation of the core layer thickness (from 0.9 d0 to 0.3 d0), but the resulting changes of the stiffness and damping of the overall structure have no significant influence on the TL up to approximately 1 kHz for the analysed CCLD design. Between 1 kHz and 5 kHz, however, the TL can be influenced considerably well by the actuation pressure applied, due to a damping-dominated behaviour around the critical frequency.

Textiles have a very long history, but they are far from becoming outdated. They gain new importance in technical applications, and man-made fibers are at the center of this ongoing innovation. The development of high-tech textiles relies on enhancements of fiber raw materials and processing techniques. Today, melt spinning of polymers is the most commonly used method for manufacturing commercial fibers, due to the simplicity of the production line, high spinning velocities, low production cost and environmental friendliness. Topics covered in this review are established and novel polymers, additives and processes used in melt spinning. In addition, fundamental questions regarding fiber morphologies, structure-property relationships, as well as flow and draw instabilities are addressed. Multicomponent melt-spinning, where several functionalities can be combined in one fiber, is also discussed. Finally, textile applications and melt-spun fiber specialties are presented, which emphasize how ongoing research efforts keep the high value of fibers and textiles alive.

The implementation of wind turbines as a source of sustainable, renewable energy is increasing. Although the prospects of renewable energy development are promising, ice accumulation on turbine blades still stands as a major operational issue. Excessive ice mass on turbine blades can lead to damage or total failure of the blades but also to the nacelle gearbox and to the generator. Therefore, a detailed understanding of the ice accumulation on the composite blades and the effect on their modal properties can be beneficial and give an insight before catastrophic failure occurs. On the one hand, it can be understood how ice accumulation affects the profile of the composite surface to consequently identify the relationships between ice accumulation and mass, stiffness, as well as damping distribution. On the other hand, by mapping these relationships, the first step is performed towards solving the inverse problem, which is to identify critical ice accumulation at an early stage based on modal properties. In this way, ice detection and identification can provide significant savings in time and costs. To investigate the basic relationships between ice accumulation and structural dynamic behaviour, an experimental rotor test rig is developed, combining an electromotor with a climate chamber. The test rig simulates various environmental conditions under different rotational speeds and ice distributions. The first experimental tests are performed on a glass-fibre reinforced epoxy rotor, and several measurements are conducted deploying different kinds of icing and temperature conditions. Various sensors are applied to characterise the vibration response as well as mass, type, and spatial distribution of the ice. The results are evaluated with regard to identifying unknown relations between ice accumulation and the structural dynamic behaviour of composite rotors.

The study summarizes the results of monitoring the properties of two types of sorbents, BC1 (biochar sample 1) and BC2a (biochar sample 2), prepared by pyrolysis of bamboo biomass (BC1) and as its composite with montmorillonite K10 (BC2a). The main goal was to study their applicability to the Tc (VII) separation from liquid wastes, using NH4ReO4 as a carrier. The research was focused on determining the sorbents surface properties (by XRF (X-ray fluorescence) method and potentiometric titration in order to determine the properties of surface groups—Chemical Equilibrium Model (CEM) and Ion Exchange Model (IExM) models were applied here). As well as monitoring Tc (VII) (+Re(VII)) sorption, especially to determine equilibrium isotherm, the influence of pH and kinetics. The subject of research was also the dynamics of sorption, including its mathematical–physical modeling. Both sorbents have good properties against Tc (VII), however BC2a, due to the presence of montmorillonite, is more advantageous in this respect. It has a higher sorption capacity and faster kinetic investigation. An important finding is that the optimal pH is 2–3, which is related not only to the protonation of surface groups (they have a positive charge), but also to the negative form of the existence of Tc (VII) and Re (VII): TcO4− and ReO4−.

Patellofemoral (PF) disorders are considered a major clinical complication after total knee replacement (TKR). Malpositioning and design of the patellar component impacts knee joint dynamics, implant fixation and wear propagation. However, only a limited number of studies have addressed the biomechanical impact of the patellar component on PF dynamics and their results have been discussed controversially. To address these issues, we implemented a musculoskeletal multibody simulation (MMBS) study for the systematical analysis of the patellar component’s thickness and positioning on PF contact forces and kinematics during dynamic squat motion with virtually implanted unconstrained cruciate-retaining (CR)-TKR. The patellar button thickness clearly increased the contact forces in the PF joint (up to 27%). Similarly, the PF contact forces were affected by superior–inferior positioning (up to 16%) and mediolateral positioning (up to 8%) of the patellar button. PF kinematics was mostly affected by the mediolateral positioning and the thickness of the patellar component. A medialization of 3 mm caused a lateral patellar shift by up to 2.7 mm and lateral patellar tilt by up to 1.6°. However, deviations in the rotational positioning of the patellar button had minor effects on PF dynamics. Aiming at an optimal intraoperative patellar component alignment, the orthopedic surgeon should pay close attention to the patellar component thickness in combination with its mediolateral and superior–inferior positioning on the retropatellar surface. Our generated MMBS model provides systematic and reproducible insight into the effects of patellar component positioning and design on PF dynamics and has the potential to serve as a preoperative analysis tool.

In the present study, it could be shown that by integration of a piezoceramic transducer in a fiber-reinforced door side panel, a flat loudspeaker can be realized. Taking into account the given restrictions, the integration position has been identified, where the geometry decouples the vibrating membrane from the supporting surface. With the help of an acoustic finite-element simulation, the main design variables of the integration position were found and the relevant effects for sound radiation were made visible. The manufacturing of the test specimen with piezoceramic transducers was performed using vacuum-assisted resin infusion and the long fiber injection procedure. The effect on the real sound radiation behavior of the door side panel with a material-immanent loudspeaker was experimentally determined using laser scanning vibrometry and sound pressure measurements. The presented work shows, for the first time, the high potential of acoustic functionalization of lightweight structures during the manufacturing process for the realization of lightweight and space-saving loudspeakers in a production-ready process.

This paper addresses supply risk in the oncological medicine supply chain (SC) in Colombia. A system dynamics model was developed for assessing supply risk impact on SC operation and performance. The costs of risk and logis-tics operation were evaluated in current conditions and in a risk mitigation scenario. The model was based on a systematic analysis of supply networks, mainly concerning the reduction of overall SC costs and improving service, quality and opportunity performance index. This article has resulted from research into SC risk management (SCRM) carried out by the Universidad Nacional de Colombia’s SEPRO research group.

En las organizaciones actuales la tomade decisiones está acompañada de cierto grado deincertidumbre, lo que no permite planificar sobre resultadosciertos. En algunas ocasiones medir estosresultados también implica incertidumbre asociadacon la ambigüedad o subjetividad del instrumentoutilizado. Como solución para este problema, sepropone un sistema de medición y análisis basadoen el Balance Scorecard que incorpora técnicas delógicas difusas para disminuir la incidencia de estaincertidumbre en los procesos de toma y análisis dedecisiones.

En este artículo se desarrolla un modelo de inferencia difusa para la toma de decisiones en condiciones de incertidumbre aplicado al diseño de productos bajo un esquema de ingeniería concurrente. Los requisitos del cliente y los criterios de los diferentes equipos interdisciplinarios para evaluar un diseño en particular son presentados como variables difusas. El modelo aquí desarrollado es aplicado a una empresa de confecciones.In this article a fuzzy inference model is developed for decision making under uncertainty conditions, applied to the design of products under a scheme of concurrent engineering. Customer requirements and criteria of different interdisciplinary teams to evaluate a particular design are presented as fuzzy variables. The model developed is applied to a garment company.

En este artículo se muestran cuatro modelos de los sistemas MRP cerrados con incertidumbre en los componentes de producción, como son: la capacidad necesaria de fabricación de cada producto, el tiempo de entrega y la disponibilidad del inventario. Dichos parámetros se tratan mediante la lógica difusa modelizando un sistema MRP cerrado determinista. Por tanto, se presentan inicialmente tres modelos de sistema MRP cerrado, donde cada uno considera de forma independiente la incertidumbre en capacidad, tiempo de entrega y disponibilidad de inventario. Igualmente, se presenta un cuarto modelo de sistema MRP cerrado que de forma conjunta analiza la incertidumbre en los tres parámetros mencionados. Cada uno de estos modelos es validado con información de una empresa del sector eléctrico colombiano, evaluando el costo total del plan de producción, nivel de inventarios, nivel de servicio y complejidad computacional.Neste artigo mostram-se quatro modelos dos sistemas MRP fechados com incerteza nos componentes de produção, como são: a capacidade necessária de fabricação da cada produto, o tempo de entrega e a disponibilidade do inventario. Ditos parâmetros tratam-se mediante a lógica difusa modelando um sistema MRP fechado determinista. Por tanto, apresentam-se inicialmente três modelos de sistema MRP fechado, onde a cada um considera de forma independente a incerteza em capacidade, tempo de entrega e disponibilidade de inventario. Igualmente, apresenta-se um quarto modelo de sistema MRP fechado que de forma conjunta analisa a incerteza nos três parâmetros mencionados. A cada um destes modelos é validado com informação de uma empresa do setor elétrico colombiano, avaliando o custo total do plano de produção, nível de estoques, nível de serviço e complexidade computacional.In this paper, we present four models of uncertainty in the MRP closed systems in the production components, such as: manufacturing capacity of each product, delivery time and inventory availability. These parameters are processed by the fuzzy logic by modeling an MRP closed system deterministic. Therefore, three models are initially MRP closed system, where each independently consider uncertainty in capacity, delivery time and inventory availability. Also, we present a fourth model of MRP closed system jointly analyzes the uncertainty in the three parameters mentioned above. Each of these models is corroborated with information from a company in the Colombian electricity area, evaluating the total cost of the production plan, inventory levels, service level and computational complexity.

Este artículo presenta la aplicación del proceso de análisis jerárquico – Método AHP extendido con lógica difusa en la selección de una herramienta de software para logítica tipo WMS (Warehouse Management System) en un astillero Colombiano. El método AHP ha sido utilizado ampliamente para resolver problemas de análisis de decisión en donde es necesario involucrar un alto número de factores y variables tanto cualitativas como cuantitativas, sin embargo, la mayor critica a este método es que el mismo no permite la inclusión de juicios de valor en una escala continua, sino discreta, lo cual se puede corregir al integrar la lógica difusa. Este problema encuentra solución con la extensión del método AHP con lógica difusa, desarrollado por Chang en 1996. Adaptado para un contexto especifico como el de un Astillero en Colombia.

Este artículo presenta la aplicación del modelo de inventario manejado por el vendedor VMI (Vendor Managed Inventory) en una empresa colombiana de distribución de alimentos, realizando una definición clara de ella y analizando los elementos más relevantes al respecto, como son los beneficios y los modelos más importantes encontrados en la literatura científica sobre VMI. Además, se hace una evaluación comparativa de dos métodos propuestos en la literatura para el cálculo de la cantidad de reabastecimiento con VMI, los cuales se comparan con el procedimiento implementado en la empresa de estudio.Este artigo apresenta a aplicação do modelo de inventario manejado pelo vendedor VMI (Vendor-Managed Inventory) em uma empresa colombiana de distribuição de alimentos, realizando uma definição clara dela e analisando os elementos mais relevantes ao respeito, como sao os beneficios e os modelos mais importantes encontrados na literatura científica sobre VMI. Além disso, faz-se uma avaliação comparativa de dois métodos propostos na literatura para o cálculo da quantidade de reabastecimento com VMI, os quais se comparam com o procedimento implementado na empresa de estudo.This paper presents the application of VMI (Vendor Managed Inventory) in a Colombian enterprise that distributes food products. Here it is shown a clear definition of VMI and it is analyzed the key elements and the most important VMI models that can be found in related research literature. Also presents a comparative assessment of two methods proposed in the literature for calculating the replenishment quantities in a VMI context, which are compared with the current procedure implemented for such propose in the company.

Este artículo presenta los resultados de una investigación llevada a cabo por los grupos de investigación SEPRO y GICO, de la Universidad Nacional, en la industria astillera colombiana, que busca coordinar agentes autónomos en una cadena de suministro (CS) en un entorno descentralizado, donde los compradores (astilleros) tienen una configuración productiva por proyectos. Con este fin se desarrolló un modelo exacto de programación lineal multicriterio para reducir el déficit en el cumplimiento de la demanda y minimizarle el costo logístico a todos los miembros de la CS, considerando la autonomía inherente a sus integrantes y la necesidad de coordinar su operación logística, mediante el conocimiento de la demanda de clientes y la capacidad de los proveedores en los períodos del horizonte de planeación. El modelo propuesto logró disminuir los costos totales en un 0,047% de unidades monetarias, además de identificar en forma explícita los costos logísticos para una cadena tan compleja.

Este artículo surge como resultado de una investigación en el tema de Vendor Managed Inventory (VMI) en la cadena productiva de deshidratados de plátano, compuesta por una planta deshidratadora (proveedor) y una granja porcina (cliente), incorporando el costo de transporte del producto como parámetro integral de los costos de inventarios, con el fin de examinar las prácticas de gestión de inventarios antes y después de la implementación de VMI. Se muestra inicialmente la contextualización de la cadena en el ámbito del sector y la agroindustria del plátano en Colombia. Posteriormente, se desarrolla el modelo de coordinación de inventarios, tomando como referencia el modelo propuesto por Yao, et al. [1], el cual se fundamenta en el modelo de lote económico de pedido (EOQ). Se realiza la modelación matemática en los escenarios sin VMI y con VMI, incorporando el costo de transporte del producto al costo total del manejo de inventarios. Los resultados muestran que la adopción de VMI genera ahorros para la cadena integrada y como el costo de transporte resulta ser un elemento individual relevante en la estructura de costos logísticos de la cadena estudiada.

In aero engines, noise absorption is realised by acoustic liners, e.g., Helmholtz resonator (HR) liners, which often absorb sound only in a narrow frequency range. Due to developments of new engine generations, an improvement of overall acoustic damping performance and in particular more broadband noise absorption is required. In this paper, a new approach to increase the bandwidth of noise absorption for HR liners is presented. By replacing rigid cell walls in the liner’s honeycomb core structure by flexible polymer films, additional acoustic energy is dissipated. A manufacturing technology for square honeycomb cores with partially flexible walls is described. Samples with different flexible wall materials were fabricated and tested. The acoustic measurements show more broadband sound absorption compared to a reference liner with rigid walls due to acoustic-structural interaction. Manufacturing-related parameters are found to have a strong influence on the resulting vibration behaviour of the polymer films, and therefore on the acoustic performance. For future use, detailed investigations to ensure the liner segments compliance with technical, environmental, and life-cycle requirements are needed. However, the results of this study show the potential of this novel liner concept for noise reduction in future aero-engines.

El uso de la teoría de los conjuntos difusos como una metodología para el modelado y análisis de sistemas de decisión es de particular interés para investigadores en ingeniería industrial, debido a la capacidad para permitir un análisis cualitativo y cuantitativo de los problemas que implican vaguedad e imprecisión. Es así como, en un esfuerzo por obtener una mejor compresión del uso de la lógica difusa en la ingeniería industrial y más específicamente en el campo de la planificación de la producción, se proporciona en el presente artículo un problema de planeación de requerimiento de materiales (MRP) bajo condiciones de incertidumbre aplicado a la industria automotriz, y el cual es solucionado a través de programación lineal paramétrica difusa.

Un enfoque racional para la toma de decisiones debe tener en cuenta la subjetividad humana, en lugar de emplear sólo medidas con distribución de probabilidad. Esta actitud hacia la incertidumbre del comportamiento humano ha llevado al estudio de un relativamente nuevo campo de análisis de decisión como es, la toma de decisiones difusas, la cual incorpora la subjetividad y la imprecisión en la formulación de modelos y procesos de solución y representa una atractiva herramienta de ayuda a la investigación en ingeniería industrial cuando la dinámica de las decisiones están limitadas por imprecisiones en los modelos formulados. El presente artículo hace un resumen de las aplicaciones que ha tenido la lógica difusa en el campo industrial y presenta un modelo MRP al cual se aplican algunos de estos conceptosA rational approach toward decision-making should take into account human subjectivity, rather than employing only objective probability measures. This attitude towards the uncertainty of human behavior led to the study of a relatively new decision analysis field: Fuzzy decision making, which incorporates imprecision and subjectivity into the model formulation and solution process and represents an attractive tool to aid research in industrial engineering when the dynamics of the decision environment limit the specification of model objectives, constraints and the precise measurement of model parameters. This article gives an overview of the applications that have fuzzy logic in the industrial field and presents a MRP model to which apply some of these concepts

Este artículo presenta el estudio de los sistemas de indicadores de desempeño de cadenas de abastecimiento en ambientes de incertidumbre. Se hace una distinción de los conceptos riesgo e incertidumbre, y se exponen las principales fuentes y estructuras de incertidumbre en cadenas de abastecimiento propuestas por diversos autores. Se mencionan las principales características de los indicadores de desempeño y se fusionan los dos elementos conceptuales (incertidumbre e indicadores de desempeño), para estudiar los modelos matemáticos que emplean los principios de la lógica difusa a fin de medir el desempeño de cadenas de abasto en ambientes de incertidumbre. Finalmente, se realiza una aplicación de un modelo en la cadena de abasto del sector panificador de Palmira. Los sistemas administrativo, talento humano y operativo fueron evaluados en 36 panaderías.

Actualmente las empresas son más complejas y requieren procesos de negocio flexibles que sean soportados efectivamente en toda la empresa por sistemas de tecnologías de la información (TI). La implantación de una arquitectura empresarial parte del establecimiento de un conjunto de directrices arquitectónicas que permitan asegurar un desarrollo armónico entre los modelos y necesidades de la empresa, con los procesos de negocio y las tecnologías de información. Este conjunto de directrices estratégicas de TI debe partir de la misión de la empresa y del reconocimiento de las estrategias y actividades de negocio que soportan dicha misión, y derivan en la información necesaria para la operación de la organización, las tecnologías requeridas para soportar la operación y los procesos para implementar nuevas tecnologías como respuesta a los cambios y necesidades de la empresa, en la medida en que las prioridades cambian. En este artículo se hace referencia a los orígenes del concepto de arquitectura empresarial, a los dominios de arquitectura que representan las vistas del negocio y a los beneficios que representa la arquitectura empresarial para una organización.Currenlty, companies are more complex and require flexible business processes, which are actually supported by IT systems. The introduction of an enterprise architecture starts on the establishment of a set of architectural guidelines, which henceforth ensure a harmonious development between models and business needs, with business processes and information technologies. This set of strategic directions of IT, should be based on the company's mission and the recognition of the strategies and business activities which support this mission and result in the necessary information for the operation of the organization, technologies required to support the operation, and processes to implement new technologies in response to changes and needs of the company, to the extent priorities change. This article is referred to the origins of the enterprise architecture concept, to the realms of architecture, representing the views of the business, and benefits from the enterprise architecture for an organization

The development of new materials for biological application requires in vitro testing of cell/surface interactions. Cell adhesion and spreading are difficult to quantify as most materials are non-transparent and transmission microscopy cannot be used. Contrast in reflection microscopy is rather poor. We propose an alternative method for the automated screening of cell attachment and spreading using backscattered electron imaging of scanning electron microscopy. The enhanced cell contrast permits study of cell/material interactions by little differences between cells and material.

El artículo expone un estudio realizado sobre el proceso de doblado en una empresa, para determinar qué factores tienen efecto sobre las dimensiones (longitud y ángulo de doblado) de las piezas de metal obtenidas. Acorde con la metodología de Diseño de Experimentos se desarrolla este estudio, para el cual se consideraron cuatro factores (operario, dobladora, material y grosor del material), cada uno con dos niveles que fueron seleccionados de manera aleatoria de una población de posibles niveles. Dos réplicas se tomaron para cada combinación de tratamientos. Las corridas experimentales se hicieron de modo aleatorio para garantizar la ausencia de sesgo en la recolección de los datos. Con lo anterior se realizaron en total 32 corridas experimentales, correspondientes a 32 datos de longitud y 32 datos de ángulo, considerando todas las posibles combinaciones. El análisis de los resultados muestra que las dimensiones de las piezas dobladas fluctúan. Para la longitud de doblado, se encontró que existe variabilidad en la población de niveles de los factores Dobladora y Grosor y en la interacción Dobladora*Operario; respecto al ángulo de doblado, se encontraron variaciones en la población de niveles de los factores Operario y Grosor y la interacción Operario*Grosor. En síntesis, el proceso de doblado presenta variaciones considerables que pueden ser preocupantes a la hora de requerir mucha precisión para un proceso de ensamble posterior.O artigo expõe um estudo realizado sobre o processo de dobra em uma empresa, para determinar os fatores que têm efeito sobre as dimensões (comprimento e ângulo de dobra) das peças de metal obtidas. Acorde com a metodologia de Desenho de Experimentos se desenvolve este estudo, para o qual se consideraram quatro fatores (operário, máquina de dobra, material e espessura do material), cada um com dois níveis que foram selecionados de maneira aleatória de uma população de possíveis níveis. Duas repetições se tomaram para cada combinação de tratamentos. As corridas experimentais se fizeram de modo aleatório para garantir a ausência de erro sistemático na colheita dos dados. Com o anterior se realizaram no total 32 corridas experimentais, correspondentes a 32 dados de comprimento e 32 dados de ângulo, considerando todas as possíveis combinações. A análise dos resultados amostra que as dimensões das peças dobradas oscilam. Para o comprimento de dobrado, se encontrou que existe variabilidade na população de níveis dos fatores Maquina de Dobra, Espessura e na interação Maquina de Dobra*Operário; respeito ao ângulo de dobra, se encontraram variações na população de níveis dos fatores Operário e Espessura e na interação Operário*Espessura. Em síntese, o processo de dobra apresenta variações consideráveis que podem ser preocupantes na hora de requerer muita precisão para um processo de montagem posterior.The paper shows a study made about the bending process in a company, to define which factors have an effect on the dimensions (bending length and bending angle) of the metal pieces obtained. The study develops according to Design of Experiments methodology. For this study, four factors were considered (operator, bending machine, sheet material, sheet thickness) at two levels each factor. Levels were chosen at random from a variety of possible levels; two replicates were taken for each treatment combination. Experimental runs were made at random to ensure absence of systematic error in data obtaining. There were made 32 experimental runs representing 32 bending length data and 32 bending angle data with all possible combinations of factor levels. The data analysis shows that dimensions of bended pieces change. Relating the bending length, there are variability in levels of the factors Bending Machine and Thickness, and in the interaction Bending Machine*Operator. Considering bending angle, there are variability in levels of the factors Operator and Thickness and the interaction Operator*Thickness. In brief, bending process presents considerable variations that can be worrying when requiring great accuracy for a later assembly process.

This paper emerges as a research result of the Vendor Managed Inventory (VMI) issue to a dehydrated plantain productive chain, which is composed by a dehydrating plant (supplier) and a pig-raise farm (client), adding the product transport cost as an integral parameter to inventory cost, in order to examine the inventory process practice before and after establishing VMI. Initially a chain contextualization in the field sector and the Colombian plantain agro-industry is shown. Then, the inventory coordination model is formulated taking as reference the model proposed by Yao, et al. [1], which is based on the model of economic batch supplier order. According to the previous information, the mathematical model is then applied with VMI and without VMI, after that, the product transport cost is incorporated to the total cost of management inventory. The result shows that VMI adoption generates savings for the integrated chain and how the transport cost becomes a relevant individual element in the structure for logistics cost of the analyzed chain.

The paper presents preliminary numerical and experimental studies of active textile-reinforced thermoplastic composites with embedded sensor-actuator arrays. The goal of the investigations was the assessment of directional sound wave generation capability using embedded sensor-actuator arrays and developed a wave excitation procedure for ultrasound measurement tasks. The feasibility of the proposed approach was initially confirmed in numerical investigations assuming idealized mechanical and geometrical conditions. The findings were validated in real-life conditions on specimens of elementary geometry. Herein, the technological aspects of unique automated assembly of thermoplastic films containing adapted thermoplastic-compatible piezoceramic modules and conducting paths were described.

Los modelos de optimización del transporte en el sector palmicultor, buscan disminuir el costo de operación logística asociado con la asignación de vehículos en las etapas de recolección y transporte de los Racimos de Fruto Fresco (RFF) aquí, se proponen dos modelos logísticos aplicables en la gestión del transporte en la agroindustria de la palma de aceite en Colombia. El primer modelo describe la operación general y garantiza el envío de la recolección desde los puntos de acopio interno hasta los puntos de acopio externo, y de estos últimos a la planta productora. Y el segundo propone la condición single sourcing (Única fuente), para asegurar que el fruto proveniente de un lote, se asigne a sólo un acopio externo y se faciliten acciones como la inspección de la producción y el control de calidad de los lotes. La importancia de plantear un modelo single sourcing genera distintas posibilidades para evaluar escenarios en donde se ven enfrentados a diario los agentes que intervienes en este sector, buscando mecanismos de coordinación e integración. El modelo single sourcing modifica las condiciones de operación y de esta manera, se constituye en una herramienta básica que permite medir incidencias técnicas y económicas de cambios en la forma como opera el sistema de transporte. Al final se presentan los resultados, conclusiones y recomendaciones de este trabajo.

A rational approach toward decision-making should take into account human subjectivity, rather than employing only objective probability measures. This attitude towards the uncertainty of human behavior led to the study of a relatively new decision analysis field: Fuzzy decision making, which incorporates imprecision and subjectivity into the model formulation and solution process and represents an attractive tool to aid research in industrial engineering when the dynamics of the decision environment limit the specification of model objectives, constraints and the precise measurement of model parameters. This article gives an overview of the applications that have fuzzy logic in the industrial field and presents a MRP model to which apply some of these concepts.

Este artículo presenta el estudio de los sistemas de indicadores de desempeño de cadenas de abastecimiento en ambientes de incertidumbre. Se hace una distinción de los conceptos riesgo e incertidumbre, y se exponen las principales fuentes y estructuras de incertidumbre en cadenas de abastecimiento propuestas por diversos autores. Se mencionan las principales características de los indicadores de desempeño y se fusionan los dos elementos conceptuales (incertidumbre e indicadores de desempeño), para estudiar los modelos matemáticos que emplean los principios de la lógica difusa a fin de medir el desempeño de cadenas de abasto en ambientes de incertidumbre. Finalmente, se realiza una aplicación de un modelo en la cadena de abasto del sector panificador de Palmira. Los sistemas administrativo, talento humano y operativo fueron evaluados en 36 panaderías.

Un enfoque racional para la toma de decisiones debe tener en cuenta la subjetividad humana, en lugar de emplear sólo medidas con distribución de probabilidad. Esta actitud hacia la incertidumbre del comportamiento humano ha llevado al estudio de un relativamente nuevo campo de análisis de decisión como es, la toma de decisiones difusas, la cual incorpora la subjetividad y la imprecisión en la formulación de modelos y procesos de solución y representa una atractiva herramienta de ayuda a la investigación en ingeniería industrial cuando la dinámica de las decisiones están limitadas por imprecisiones en los modelos formulados. El presente artículo hace un resumen de las aplicaciones que ha tenido la lógica difusa en el campo industrial y presenta un modelo MRP al cual se aplican algunos de estos conceptos

La logística de la ciudad es uno de los asuntos principales en logística debido que los centros urbanos tienden a crecer y consolidar las actividades económicas e industriales con aquellas sociales y humanas. La gran mayoría de los estudios se centran en el enfoque tradicional de transporte, que tiene como objetivo explicar las variables relacionadas con la oferta de transporte, en lugar de analizar la demanda real. Existe una falta de comprensión sobre el comportamiento de los clientes, lo que es explícito en estudios previos relacionados con la logística de la ciudad. Este trabajo tiene como objetivo ofrecer un análisis de las principales tendencias y el comportamiento de las compras en el hogar, específicamente en la compra de alimentos, mediante el uso de fuentes primarias de información y herramientas estadísticas. Los resultados obtenidos en un centro urbano de rápido crecimiento en Colombia, ofrecen un marco para comprender el comportamiento de las compras en los hogares, con base en tres variables principales: a) Los productos, b) Vehículos y c) La frecuencia de compra en relación con las instalaciones para la adquisición de alimentos (tiendas).

En el presente artículo se modeliza el comportamiento de la infraestructura vial de los corredores logísticos de Colombia, utilizando dinámica de sistemas para evaluar los efectos de las políticas de inversión que se realizan en la red pavimentada. Para ello, se consideran cinco categorías que permiten evaluar la calidad de la red pavimentada definidas por el Instituto Nacional de Vías y Transporte - INVIAS. El modelo contiene la parametrización para evaluar el desgaste de las vías en función de tráfico promedio y de las inversiones que se realizan para la rehabilitación y el mantenimiento de las vías.