Hasil untuk "Technical hydraulics"

Marion Wiese

This white paper provides an overview of the topic of "technical debt" and presents an approach for managing technical debt in teams. The white paper is based on the results of my dissertation, which aimed to translate scientific findings into practical guidance. To this end, I collaborated with other researchers to support three teams from different companies in adapting and establishing a technical debt management system tailored to their specific needs. Research findings were supplemented with details or additional approaches. Research results that were less practical were discarded. The result is a guide on establishing technical debt management within a team. The guide is intended to provide orientation and not be a rigid framework. We distinguish between "best practices" and "nice-to-haves." "Best practices" are understood to be all approaches that were adopted by all three teams. "Nice-to-haves" were used by at least one team. In many places, it is explicitly mentioned that the team should decide together how to design the process. This also applies, of course, to all areas where this was not explicitly mentioned. This white paper explicitly does not cover the establishment of technical debt management across the entire company, but provides suggestions for this at the end.

Brian Bell, Teresa Thomas, Sang Won Lee et al.

To obtain employment, aspiring software engineers must complete technical interviews -- a hiring process which involves candidates writing code while communicating to an audience. However, the complexities of tech interviews are difficult to prepare for and seldom faced in computing curricula. To this end, we seek to understand how candidates prepare for technical interviews, investigating the effects of preparation methods and the role of education. We distributed a survey to candidates (n = 131) actively preparing for technical interviews. Our results suggest candidates rarely train in authentic settings and courses fail to support preparation efforts -- leading to stress and unpreparedness. Based on our findings, we provide implications for stakeholders to enhance tech interview preparation for candidates pursuing software engineering roles.

Hlekane Ngobeni, Mike Wa Nkongolo

The evolving of digital transformation and increased use of technology comes with increased cyber vulnerabilities, which compromise national security. Cyber-threats become more sophisticated as the technology advances. This emphasises the need for strong risk mitigation strategies. To define strong and robust cybersecurity, policies requires an integrated approach of balancing technical expertise with public input. This paper aims to explore strategies used to balance technical expertise and public input to develop effective and robust cybersecurity policies. It also studied how the effective integration of technical expertise with public input is critical to developing effective strategies and resilient cybersecurity frameworks that strengthens national security. A lack of a holistic approach and collaborative efforts to cybersecurity can hinder the effectiveness of cybersecurity policies. This paper followed a systematic literature review with bibliometric analysis using the PRISMA methodology to explore how technical expertise and public input can be integrated to guide cybersecurity policy making. The thematic analysis identified five important themes in developing effective cybersecurity policies, these key themes are: Multi-Stakeholder Involvement and Human Centric Approaches (MSI & HCA), Governance and Policy Frameworks (GPF), Technical Infrastructure (TI), Evaluation and Compliance (EC), and Legal Rights and Sovereignty (LRS). The synthesis shows that there is no adequate exploration of collaborative efforts which undermines the effectiveness of the cybersecurity policies. The findings suggest that inclusive, flexible governance strategies that integrate public input at every stage are necessary for future cybersecurity policy research and practice, which must shift away from a primarily technical and legal perspective.

Pedro Saravia Celis

Esta edición especial de la revista Agua, Saneamiento & Ambiente celebra los 60 años de ERIS con una selección de artículos científicos que reflejan la diversidad y profundidad de su impacto académico. Los estudios abordan temas como la presencia de metales tóxicos en cultivos, la eficiencia de desinfección en aguas residuales, el análisis de nitritos y nitratos en drenajes urbanos, la biodigestión de residuos orgánicos, y propuestas para el manejo de áreas críticas de recarga hídrica. También se incluyen investigaciones sobre ecosistemas acuáticos, como el estudio batimétrico de la Laguna de Ayarza y la presencia de amebas testadas en lagos centroamericanos, evidenciando el enfoque interdisciplinario y regional de la Escuela.

Hicham Hammouchi, Narjisse Nejjari, Ghita Mezzour et al.

Data breaches have begun to take on new dimensions and their prediction is becoming of great importance to organizations. Prior work has addressed this issue mainly from a technical perspective and neglected other interfering aspects such as the social media dimension. To fill this gap, we propose STRisk which is a predictive system where we expand the scope of the prediction task by bringing into play the social media dimension. We study over 3800 US organizations including both victim and non-victim organizations. For each organization, we design a profile composed of a variety of externally measured technical indicators and social factors. In addition, to account for unreported incidents, we consider the non-victim sample to be noisy and propose a noise correction approach to correct mislabeled organizations. We then build several machine learning models to predict whether an organization is exposed to experience a hacking breach. By exploiting both technical and social features, we achieve a Area Under Curve (AUC) score exceeding 98%, which is 12% higher than the AUC achieved using only technical features. Furthermore, our feature importance analysis reveals that open ports and expired certificates are the best technical predictors, while spreadability and agreeability are the best social predictors.

Christoph Auer, Maksym Lysak, Ahmed Nassar et al.

This technical report introduces Docling, an easy to use, self-contained, MIT-licensed open-source package for PDF document conversion. It is powered by state-of-the-art specialized AI models for layout analysis (DocLayNet) and table structure recognition (TableFormer), and runs efficiently on commodity hardware in a small resource budget. The code interface allows for easy extensibility and addition of new features and models.

Binh Vinh Duc Nguyen, Andrew Vande Moere

This technical description details the design and engineering process of a semi-autonomous robotic partition. This robotic partition prototype was subsequently employed in a longer-term evaluation in-the-wild study conducted by the authors in a real-world office setting.

Konstantinos Demertzis, Stavros Demertzis, Lazaros Iliadis

Artificial intelligence is the branch of computer science that attempts to model cognitive processes such as learning, adaptability and perception to generate intelligent behavior capable of solving complex problems with environmental adaptation and deductive reasoning. Applied research of cutting-edge technologies, primarily computational intelligence, including machine/deep learning and fuzzy computing, can add value to modern science and, more generally, to entrepreneurship and the economy. Regarding the science of civil engineering and, more generally, the construction industry, which is one of the most important in economic entrepreneurship both in terms of the size of the workforce employed and the amount of capital invested, the use of artificial intelligence can change industry business models, eliminate costly mistakes, reduce jobsite injuries and make large engineering projects more efficient. The purpose of this paper is to discuss recent research on artificial intelligence methods (machine and deep learning, computer vision, natural language processing, fuzzy systems, etc.) and their related technologies (extensive data analysis, blockchain, cloud computing, internet of things and augmented reality) in the fields of application of civil engineering science, such as structural engineering, geotechnical engineering, hydraulics and water resources. This review examines the benefits and limitations of using computational intelligence in civil engineering and the challenges researchers and practitioners face in implementing these techniques. The manuscript is targeted at a technical audience, such as researchers or practitioners in civil engineering or computational intelligence, and also intended for a broader audience such as policymakers or the general public who are interested in the civil engineering domain.

Editor en jefe

Sarno Luca, Wang Yongqi, Tai Yih-Chin et al.

Debris flows and avalanches are dangerous natural phenomena, characterized by the gravity-driven motion of granular media immersed in a fluid. For an appropriate hazard assessment or disaster mitigation by scenario investigation, it is crucial to capture the underlying dynamics of the granular solid phase. For this purpose, a multilayer depth-averaged approach represents a promising and computationally efficient tool over fully three-dimensional models. Here we use a mathematically well-posed multilayer model, which implements the µ(I)-rheology and a dilatancy law depending on the inertial number, I, and compare the numerical results of the model with laboratory experiments of steady uniform chute flows over an erodible bed. The well-posedness of the model for any value of I, which is essential to get convergent numerical solutions, is achieved by considering an approximation of the in-plane stress gradients, directly emerging from the µ(I)-rheology. The predicted velocity profiles show a very good agreement with the experimental ones, measured by particle image velocimetry (PIV). The volume fraction profiles by the multilayer model are also in good qualitative agreement with those measured by using the stochastic-optical method (SOM), while they tend to overestimate the volume fraction measurements in the more dilute upper region, closer to the free surface.

Abdolreza Taheri, Robert Pettersson, Pelle Gustafsson et al.

A sizable part of the fleet of heavy-duty machinery in the construction equipment industry uses the conventional valve-controlled load-sensing hydraulics. Rigorous climate actions towards reducing CO$_{2}$ emissions has sparked the development of solutions to lower the energy consumption and increase the productivity of the machines. One promising solution to having a better balance between energy and performance is to build accurate models (digital twins) of the real systems using data together with recent advances in machine learning/model-based optimization to improve the control systems. With a particular focus on real-world machines with multiple flow-controlled actuators and shared variable-displacement pumps, this paper presents a generalized machine learning approach to modeling the working pressure of the actuators and the overall pump pressures. The procedures for deriving reaction forces and flow rates as important input variables to the surrogate models are described in detail. Using data from a real loader crane testbed, we demonstrate training and validation of individual models, and showcase the accuracy of pressure predictions in five different experiments under various utilizations and pressure levels.

Pedro Saravia

Sevgi Cavdar, Ali Uyumaz

A roadway’s capacity to drain itself is of utmost importance for the safety and comfort of its users. Standing water and any amount of channelized flow on roadways create nuisances to the users, and the extent of encroachment into the lanes and the water-film thickness over the lanes are crucial for motorists with relatively high speed. Guidelines cover a wide range of subjects from size and type of inlets, which capture the channelized flow for conveyance into enclosed drains, to the decision for slope orientation, but the guidelines seem to lack in checking the depth of channelized flow. HEC-22 (the urban drainage design manual of US Department of Transportation) endorses limiting the flow depths to curb height (as if the concern is no longer the roadway users) and fixes the criterion for the inlet spacing (restricted to 90 to 150 m) to maximum allowable flow spreads. This study analyzed the maximum allowable inlet spacing via setting three criteria: fixed maximums to flow depth, spread for the channel flow, and to over-lane water-film thickness. The impact of slope orientation on inlet spacing is tested along with some other factors for roadways of two types (local and highway). The results were graphed for various uniform slope orientations under a wide range of rainfall intensities for the determined inlet spacing values. This was performed by combining a kinematic wave equation solution to dismiss the conditions that lead to hydroplaning depths when using the Rational Method and Manning’s equation to obtain water depths and inlet spacings for an inlet of full capture capacity. It is found that the allowable spacing values do not constitute any major restrictions in highway setting (3 m shoulder) in terms of recommended spacing. In the local setting, however, with a maximum spread of 1.8 m, maximum allowable inlet spacing becomes a limitation in many orientations, and slope optimization under such conditions becomes crucial at times when providing the same spacing for two orientations.

Esthefany Fuentes

La inversión térmica o “volteo” es una mezcla que se da en algunos lagos. Está relacionada con el ciclo de energía de la tierra y su ocurrencia depende de los cambios de temperatura en la columna de agua, permitiendo reconocer las condiciones de circulación y mezcla. Según la ocurrencia de inversión, el Lago de Amatitlán, se clasifica como monomíctico cálido, ya que sus aguas se mezclan una vez al año. El Lago de Amatitlán está ubicado en el municipio de Amatitlán a 25 kilómetros de la 2 ciudad capital a 1,188 msnm y tiene un área superficial de 15.06 km . Durante años se han realizado estudios y proyectos de investigación enfocados a la parte física, química y microbiológica de sus aguas; no así la evaluación de la inversión térmica. El objetivo del presente artículo fue determinar en qué momento del año se presenta la inversión térmica en el Lago de Amatitlán. Esto se realizó utilizando datos de temperatura (parámetro importante para los sistemas lénticos) de dos puntos principales –lado Este y Oeste- a diferentes profundidades para los años 2008 al 2011. A través de gráficas pudo determinarse que la inversión térmica ocurre generalmente en los meses de noviembre, diciembre, enero y febrero.

Bianca Ileana Alas Fajardo

Este artículo presenta los resultados de la evaluación, a escala de laboratorio, de un modelo experimental de laguna facultativa diseñada a partir del método de radiación solar y carga orgánica máxima superficial para la remoción de la carga contaminante de las aguas residuales del procesamiento del café en un beneficio húmedo tecnificado. Los resultados obtenidos oscilan entre 47.17% y 78.92% de remoción de DBO5, lo cual representa un porcentaje promedio de 61.60% de remoción de la carga contaminante de los efluentes agroindustriales tratados mediante la metodología propuesta; por lo que se valida su implementación como unidad de tratamiento primario para la depuración de las aguas mieles.

Marco Antonio Moreno Alvarado

Este artículo muestra los resultados de la evaluación de un modelo experimental de lecho de roca caliza, a nivel de laboratorio, como alternativa de tratamiento primario para el ajuste del potencial de hidrógeno (pH) de las aguas mieles producidas en el beneficio de café húmedo tecnificado “Nuevo Sendero” en el periodo de cosecha 2012-2013. Los resultados de la evaluación del modelo experimental de roca caliza demostraron que es posible obtener variaciones de pH en un rango que varían de 0.29 a 2.30 unidades de pH. De esta forma el modelo experimental de lecho de roca caliza permite el ajuste de pH del agua miel del café desde un valor inicial de 4.83 unidades de pH hasta un valor de 7.43 unidades de pH, haciendo variar la altura de medio de roca caliza dentro del lecho y la velocidad ascensional de flujo, también conocida como carga hidráulica disponible. Así mismo se presentan dos ecuaciones experimentales, desarrolladas con los datos obtenidos del modelo evaluado, que relacionan la altura del medio de roca caliza, la velocidad de flujo ascensional y la variación o ajuste de pH del agua miel, con estas ecuaciones es viable diseñar lechos de roca caliza a partir de un valor de pH requerido.

Gianandrea Vittorio Messa, Qi Yang, Maria Graça Rasteiro et al.

This research work is a significant step toward further understanding of the β-σ two-fluid model for the simulation of fully-suspended slurry flows in pipeline systems, with the goal of enhancing its potential for scientific research and engineering applications. Particularly, the focus of the study is the characterization and handling of the two main empirical coefficients of the model, namely, β and σ, which require case-specific tuning based on a given set of experimental data. Reference is made to the relevant case of slurry transport in horizontal pipes with infinite length. The influence of β and σ on different features of the fluid dynamic solution has been extensively investigated, considering also the role played by the specific testing conditions. Based on these findings, a procedure for determining appropriate values of β and σ has been developed, which requires only two experimental measurements, namely the concentration profile from a test at moderate slurry concentration, and the hydraulic gradient from another test in which the same slurry flows at high concentration. The procedure has been satisfactorily tested against published experimental data on pipe transport of fine glass bead and sand slurry.

Aaron Parks-Young, Guni Sharon

This document provides technical details regarding the Hybrid-AIM simulator that was used in Sharon and Stone (2017) and Parks-Young and Sharon (2022).

Gaspare Da Fies, Martin Dutko, Daniel Peck

The homogenisation of the fracture toughness is considered in the context of a propagating hydraulic fracture. The radial (penny-shape) model is utilized, in order to incorporate the impact of the viscosity-toughness regime transition over time. A homogenisation strategy based upon temporal-averaging is investigated. This approach incorporates the instantaneous fracture velocity, meaning that it should remain effective in the case of step-wise crack advancement. The effectiveness of the approach is demonstrated for periodic toughness distributions, including those which are unbalanced, utilizing a highly accurate solver.

Terziev Angel, Panteleev Yancho, Iliev Iliya et al.

The turbulent nature of the wind above the earth’s surface depends on both the topology of the terrain and the presence of natural obstacles along the way such as low grasses and shrubs, as well as medium-tall trees. When the wind passes through the indicated obstacles, detachment is observed i.e. formation of large eddies, which are carried away by the main flow, after which they dissipate. The size of the vortices, as well as the period of dissipation, depends on the wind speed, as well as the type of obstacle. The presence of windbreak trees significantly changes the wind shear over the surface, and hence the energy potential of the wind in the vicinity of trees. In present work, the influence of the tree belt on the wind shear at the adopted prevailing wind direction is investigated. The degree of deformation of the speed profile after the obstacle in weakly complex terrain is shown. Relevant prescriptions for the location of wind turbines in the vicinity of windbreak trees are presented in view of minimum shading and maximum energy output.