Hasil untuk "Structural engineering (General)"

Edwin Giovanny Morales, Ana Gabriela Haro-Báez

This research focuses on characterizing typical displacement patterns in concentrically braced frame (CBF) systems for use in the direct displacement-based seismic design (DDBD) methodology. Using the finite-element program SeismoStruct, two-dimensional models were developed for nonlinear time–history analysis (NLTHA), employing scaled real accelerograms, conventional gravity loads, and detailed numerical models. Thirty varied CBF configurations with different numbers of storeys, spans, and bracing types were evaluated. It was found that the conventional displacement profiles, commonly used for moment-resisting frames, do not accurately represent the actual behavior of CBFs in the inelastic range. Therefore, fitted equations were developed and validated to accurately represent the actual displacements of CBF systems, accounting for factors such as the fundamental vibration period and equivalent system damping. These improvements enable the seismic design optimization, advanced displacement and drift control, and strengthen structural safety and performance in high-seismicity zones in the region. This contribution is relevant to performance-based engineering, facilitating a plausible update to regulations and best practices for seismic-resistant design.

Sandra Salazar Palomino, Yersi-Luis Huamán-Romaní, Carlos Alfredo Bocanegra García et al.

Digital competences as the use of ICT after the COVID-19 era had a very significant effect, especially in the education sector, with which university students learned to use and collaborate academically through digital platforms or media. This research work aims to analyze and describe digital competences and their collaborative attitudes in university students. The method used is descriptive research, with a quantitative approach. 1073 university students participated in a survey with questions whose answers were evaluated with the Likert scale. Resulting in the favorite place to use the Internet after home is any place because they have a device (mobile phone), which in the long term would bring consequences to visual and mental health. Despite this negative point, the university is the third favorite place that helps students greatly in academic work. In conclusion, university students successfully learned digital competences and they are taking advantage of it in their academic affairs and do work in a very collaborative way.

M. Kiran Prabha, K. Vishnu Vardhan, A. S. Santhi et al.

ABSTRACT In recent years, the incorporation of fibers into self‐compacting concrete has garnered significant attention in addressing various issues. Among the different types, basalt fiber stands out due to its excellent mechanical properties, high tensile strength, and resistance to alkali and acidic environments. This review paper addresses the impact of basalt fiber on fresh, mechanical, microstructural, and durability properties of self‐compacting concrete. It's been noted that a significant amount of research is still being conducted on using basalt fiber. This work states the basalt fiber's chemical compositions, which are crucial in its applications. Based on the literature, it has been cited that the optimum dosage of the fiber is different for the compression and tensile loads on the concrete specimens. This work actively explores basalt fiber's potential in various concrete applications. The discussion emphasizes the chemical composition and optimal dosage of basalt fiber in self‐compacting concrete and underscores the importance of further research in this area. Finally, this paper recommends other studies to understand the keen effect of basalt fiber in self‐compacting concrete.

Bianca Trinkenreich, Fabio Calefato, Geir Hanssen et al.

The adoption of Large Language Models (LLMs) is not only transforming software engineering (SE) practice but is also poised to fundamentally disrupt how research is conducted in the field. While perspectives on this transformation range from viewing LLMs as mere productivity tools to considering them revolutionary forces, we argue that the SE research community must proactively engage with and shape the integration of LLMs into research practices, emphasizing human agency in this transformation. As LLMs rapidly become integral to SE research - both as tools that support investigations and as subjects of study - a human-centric perspective is essential. Ensuring human oversight and interpretability is necessary for upholding scientific rigor, fostering ethical responsibility, and driving advancements in the field. Drawing from discussions at the 2nd Copenhagen Symposium on Human-Centered AI in SE, this position paper employs McLuhan's Tetrad of Media Laws to analyze the impact of LLMs on SE research. Through this theoretical lens, we examine how LLMs enhance research capabilities through accelerated ideation and automated processes, make some traditional research practices obsolete, retrieve valuable aspects of historical research approaches, and risk reversal effects when taken to extremes. Our analysis reveals opportunities for innovation and potential pitfalls that require careful consideration. We conclude with a call to action for the SE research community to proactively harness the benefits of LLMs while developing frameworks and guidelines to mitigate their risks, to ensure continued rigor and impact of research in an AI-augmented future.

Morgan M. Fong, Hilary Egan, Marc Day et al.

Background: Harnessing advanced computing for scientific discovery and technological innovation demands scientists and engineers well-versed in both domain science and computational science and engineering (CSE). However, few universities provide access to both integrated domain science/CSE cross-training and Top-500 High-Performance Computing (HPC) facilities. National laboratories offer internship opportunities capable of developing these skills. Purpose: This student presents an evaluation of federally-funded postgraduate internship outcomes at a national laboratory. This study seeks to answer three questions: 1) What computational skills, research skills, and professional skills do students improve through internships at the selected national laboratory. 2) Do students gain knowledge in domain science topics through their internships. 3) Do students' career interests change after these internships? Design/Method: We developed a survey and collected responses from past participants of five federally-funded internship programs and compare participant ratings of their prior experience to their internship experience. Findings: Our results indicate that participants improve CSE skills and domain science knowledge, and are more interested in working at national labs. Participants go on to degree programs and positions in relevant domain science topics after their internships. Conclusions: We show that national laboratory internships are an opportunity for students to build CSE skills that may not be available at all institutions. We also show a growth in domain science skills during their internships through direct exposure to research topics. The survey instrument and approach used may be adapted to other studies to measure the impact of postgraduate internships in multiple disciplines and internship settings.

Induni Mahisha Kumari Vijaya Kumar, Muhammad Sohail Mazhar, Shah Nawaz

Globally, industrial hemp offers consumers with over 25,000 value-added products that are valued at approximately US$4.2 billion of current market value and likely to surpass US$26.6 billion by 2025. In Northern Australia, the industrial hemp sector is at infancy stages of development. Given the suitability of certain Northern Australia’s geographical zones in terms of soil, water, and climate, a study was conducted to identify potential industrial hemp value chains. Probable value chains were developed by characterizing the production to market segments of the supply chains to determine the return on investment and analyzing the capacity of the stakeholders in terms of communication and relationships. Consequently, the strengths, weaknesses, opportunities and threats (SWOT) of the developed value chains were analyzed. This study collected data from three complementary sources that included review of the literature, results of variety trials evaluation conducted in Northern Australia, and survey of hemp industry stakeholders. Results suggested that Northern Australia offers conducive growing conditions for hemp that allows for the development of three value chains including seed, fiber and silage. The research recommended ongoing investment in the industry through engagement of public and private sector while focusing on further establishment of the industry.

Pham Duc PHONG, Trong-Chuc NGUYEN, Chuan-Bin ZHOU et al.

The non-embedded pile-board subgrade (NEPBS) is a new type of roadbed structure widely used in constructing China's high-speed railways. The paper selects the typical section of the NEPBS project of the Shanghai-Hangzhou Passenger Dedicated Line (SHPDL). It establishes an in-situ static load test system to study and analyze the bearing mechanism and applicability of the NEPBS in deep and soft soil areas. The test results show that the NEPBS has good engineering properties; as time changes, the reinforcement internal force of the loading plate and supporting beam is shown clearly; the converted bending moment agrees with the theoretical bending moment, and the plate-soil contact stress is minor. The test results can explain and analyze the theoretical calculation results. The three-way coordination of the pile-board subgrade can effectively improve the bearing capacity of the foundation soil. The deformation of the NEPBS is reasonable. One year after the completion of the roadbed and track structure, the maximum cumulative settlement of the top surface of the loading plate is 3.29mm, which meets the settlement control requirements.

Han-Min Cho, Kyu-San Jung, Ki-Tae Park

Bridges are a crucial component of social infrastructure, playing a vital role in transportation, logistics and transit. Several bridges in South Korea were constructed during the rapid development period of the 1990s and 2000s, with RC slab bridges making up a significant portion of these structures. Over time, many of these bridges have aged considerably. To address this, the “Special Act on the Safety Control and Maintenance of Establishments” was enacted in South Korea to improve bridge maintenance. However, maintenance for aging small- to medium-sized bridges, except for Type 1 bridges, remains inadequate due to budget and personnel shortages. In this study, we developed a damage assessment method to evaluate the deterioration and analyze the current state of small- to medium-sized RC slab bridges. We derived the correlation between the deflection response ratio and the stiffness reduction rate of a bridge through structural analysis. This correlation data were then used to assess the damage to actual in-service bridges. Finally, we analyzed the current state of the target bridge and validated the damage assessment method.

Lei Zhang, Andriy Miranskyy

A flaky test yields inconsistent results upon repetition, posing a significant challenge to software developers. An extensive study of their presence and characteristics has been done in classical computer software but not quantum computer software. In this paper, we outline challenges and potential solutions for the automated detection of flaky tests in bug reports of quantum software. We aim to raise awareness of flakiness in quantum software and encourage the software engineering community to work collaboratively to solve this emerging challenge.

James S. Wheaton, Daniel R. Herber

Traditional requirements engineering tools do not readily access the SysML-defined system architecture model, often resulting in ad-hoc duplication of model elements that lacks the connectivity and expressive detail possible in a SysML-defined model. Further integration of requirements engineering activities with MBSE contributes to the Authoritative Source of Truth while facilitating deep access to system architecture model elements for V&V activities. We explore the application of MBSE to requirements engineering by extending the Model-Based Structured Requirement SysML Profile to comply with the INCOSE Guide to Writing Requirements while conforming to the ISO/IEC/IEEE 29148 standard requirement statement patterns. Rules, Characteristics, and Attributes were defined in SysML according to the Guide to facilitate requirements definition, verification & validation. The resulting SysML Profile was applied in two system architecture models at NASA Jet Propulsion Laboratory, allowing us to assess its applicability and value in real-world project environments. Initial results indicate that INCOSE-derived Model-Based Structured Requirements may rapidly improve requirement expression quality while complementing the NASA Systems Engineering Handbook checklist and guidance, but typical requirement management activities still have challenges related to automation and support in the system architecture modeling software.

Lyle Regenwetter, Cyril Picard, Amin Heyrani Nobari et al.

The field of engineering is shaped by the tools and methods used to solve problems. Optimization is one such class of powerful, robust, and effective engineering tools proven over decades of use. Within just a few years, generative artificial intelligence (GenAI) has risen as another promising tool for general-purpose problem-solving. While optimization shines at precisely identifying highly-optimal solutions, GenAI excels at inferring problem requirements, bridging solution domains, handling mixed data modalities, and rapidly generating copious numbers of solutions. These differing attributes also make the two frameworks complementary. Hybrid `generative optimization' algorithms have gained traction across a few engineering applications and now comprise an emerging paradigm for engineering problem-solving. We expect significant developments in the near future around generative optimization, leading to changes in how engineers solve problems using computational tools. We offer our perspective on existing methods, areas of promise, and key research questions.

Ertugrul Basar

Noise: an enemy to be dealt with and a major factor limiting communication system performance. However, what if there is gold in that garbage? In conventional engineering, our focus is primarily on eliminating, suppressing, combating, or even ignoring noise and its detrimental impacts. Conversely, could we exploit it similarly to biology, which utilizes noise-alike carrier signals to convey information? In this context, the utilization of noise, or noise-alike signals in general, has been put forward as a means to realize unconditionally secure communication systems in the future. In this tutorial article, we begin by tracing the origins of thermal noise-based communication and highlighting one of its significant applications for ensuring unconditionally secure networks: the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange scheme. We then delve into the inherent challenges tied to secure communication and discuss the imperative need for physics-based key distribution schemes in pursuit of unconditional security. Concurrently, we provide a concise overview of quantum key distribution (QKD) schemes and draw comparisons with their KLJN-based counterparts. Finally, extending beyond wired communication loops, we explore the transmission of noise signals over-the-air and evaluate their potential for stealth and secure wireless communication systems.

Daniel Badawi, Eduardo Gildin

Physics-Informed machine learning models have recently emerged with some interesting and unique features that can be applied to reservoir engineering. In particular, physics-informed neural networks (PINN) leverage the fact that neural networks are a type of universal function approximators that can embed the knowledge of any physical laws that govern a given data-set in the learning process, and can be described by partial differential equations. The transient diffusivity equation is a fundamental equation in reservoir engineering and the general solution to this equation forms the basis for Pressure Transient Analysis (PTA). The diffusivity equation is derived by combining three physical principles, the continuity equation, Darcy's equation, and the equation of state for a slightly compressible liquid. Obtaining general solutions to this equation is imperative to understand flow regimes in porous media. Analytical solutions of the transient diffusivity equation are usually hard to obtain due to the stiff nature of the equation caused by the steep gradients of the pressure near the well. In this work we apply physics-informed neural networks to the one and two dimensional diffusivity equation and demonstrate that decomposing the space domain into very few subdomains can overcome the stiffness problem of the equation. Additionally, we demonstrate that the inverse capabilities of PINNs can estimate missing physics such as permeability and distance from sealing boundary similar to buildup tests without shutting in the well.

Peter Dørffler Ladegaard Jensen, Tim Felle Olsen, J. Andreas Bærentzen et al.

Inverse design of high-resolution and fine-detailed 3D lightweight mechanical structures is notoriously expensive due to the need for vast computational resources and the use of very fine-scaled complex meshes. Furthermore, in designing for additive manufacturing, infill is often neglected as a component of the optimized structure. In this paper, both concerns are addressed using a de-homogenization topology optimization procedure on complex engineering structures discretized by 3D unstructured hexahedrals. Using a rectangular-hole microstructure (reminiscent to the stiffness optimal orthogonal rank-3 multi-scale) as a base material for the multi-scale optimization, a coarse-scale optimized geometry can be obtained using homogenization-based topology optimization. Due to the microstructure periodicity, this coarse-scale geometry can be up-sampled to a fine physical geometry with optimized infill, with minor loss in structural performance and at a fraction of the cost of a fine-scale solution. The upsampling on 3D unstructured grids is achieved through stream surface tracing which aligns with the optimized local orientation. The periodicity of the physical geometry can be tuned, such that the material serves as a structural component and also as an efficient infill for additive manufacturing designs. The method is demonstrated through three examples. It achieves comparable structural performance to state-of-the-art methods but stands out for its significant computational time reduction, much faster than the base-line method. By allowing multiple active layers, the mapped solution becomes more mechanically stable, leading to an increased critical buckling load factor without additional computational expense. The proposed approach achieves promising results, benchmarking against large-scale SIMP models demonstrates computational efficiency improvements of up to 250 times.

Calin-Vasile PRODAN, Iacob-Liviu SCURTU

From the oldest times football, it has become a social phenomenon, being the most famous sport on the planet. Currently in the develop of football infrastructure is necessary to include related and direct activities such as: soccer coach, mass-media, stadium building, etc. Technological progress had also imposed itself on this game area, researching of the new materials and the manufacturing methods for the soccer ball. In this paper is presented the comparative aerodynamic CFD study of three types of ball: smooth sphere ball, Tsubasa and Pelada ball at three air velocity cases. In first part of the paper are presented the state of the art regarding the ball aerodynamics. The second part highlight the forces that act on the ball surface when it is shot by the player and the mathematical k-e standard turbulence model applied in this study. In the third part are establish the airflow regime by calculating the Reynolds number for each velocity case and the boundary conditions and the CFD simulation are done. The results are presented in the fourth part of the paper, comparing the obtained values for each simulation case. The conclusions and discussion regarding this study are presented in the last part of the paper.

Cláudia de Castro Jacinto, Adilson Campos de Paula Junior, Sandra Maria Gomes Monteiro Silva et al.

Population in developed countries spend most of their time indoors, whether in their homes, workplaces, stores or leisure areas. Due to the COVID-19 pandemic, this situation worsened and now, more than ever, the importance of a high Indoor Environmental Quality (IEQ) is highlighted. The IEQ is very important in building performance since it is directly related to its occupants’ comfort, health, wellbeing, and productivity and the Sick Building Syndrome (SBS) concept. Therefore, it is essential to develop tools to support designers’ decision-making in the materialization of indoor environments with higher quality. From the state-of-art analysis, it is possible to conclude that the methods to assess the overall building performance already consider the IEQ. Still, most use an approach that does not cover all relevant indicators. In this context, this paper presents the first milestone of a research work that aims to develop a new method to rate the overall IEQ of office buildings in Portugal. The main objective of the present study is to propose a list of IEQ indicators for office buildings, adapted to the Portuguese context, based on the analysis of existing rating methods for buildings and the recommendations of national and international standards.

Karim Benyahi, Mohand Said Kachi, Youcef Bouafia et al.

The object of this article is to be able to simulate the behavior of reinforced and/or prestressed concrete beam’s section in the shear loading through a model allowing the evaluation of nonlinear strains caused by shear, while taking into account the real behavior of the materials. In this approach, we are often confronted with problems of modeling uncertainties linked to some insufficiencies of the mechanical model allowing to describe the physical phenomena in a realistic way. For that, it is necessary to use a reliability model making it possible to evaluate their probability of failure, by establishing failure curves according to the different transition zones of the limit state curve of the nonlinear behavior in the shear loading up to at section failure of reinforced and/or prestressed concrete beams. In this work, we also propose a coupling of the reliability method by response surface to carry out the reliability optimization on complex mechanical models, where the mechanical and reliability models developed have been implemented on the Fortran. This allows the estimation in an efficient way of the different reliability characteristics according to each transition zone from the limit state curve to the real behavior until failure in the shear loading.

Alexander Felfernig, Stefan Reiterer, Martin Stettinger et al.

The knowledge engineering bottleneck is still a major challenge in configurator projects. In this paper we show how recommender systems can support knowledge base development and maintenance processes. We discuss a couple of scenarios for the application of recommender systems in knowledge engineering and report the results of empirical studies which show the importance of user-centered configuration knowledge organization.

Inn-Ray Chu, Rong-Long Pan, Chung-Shi Yang

<i>Background and objectives</i>: Cancer stem cells (CSCs) are obstacles to cancer therapy due to their therapeutic resistance, ability to initiate neoplasia, and roles in tumor relapse and metastasis. Efforts have been made to cure CSCs, such as the use of differentiation therapy, which induces cancer stem-like cells to undergo differentiation and decrease their tumorigenicity. Interleukin 6 (IL-6) upregulates the expression of glial fibrillary acidic protein (GFAP) in C6 glioma cells, indicating that it is able to induce the differentiation of these cells. The C6 glioma cell line forms a high percentage of cancer stem-like cells, leading us to speculate whether IL-6 signaling could modulate the differentiation of tumorigenic C6 glioma cells. However, we observed that IL-6 alone could not efficiently induce the differentiation of these cells. Therefore, different IL-6 signaling elicitors, including IL-6 alone, a combination of IL-6 and soluble IL-6 receptor (IL-6/sIL-6R), and tumor necrosis factor-α (TNF-α) plus IL-6/sIL-6R (TNF-α/IL-6/sIL-6R), were evaluated for their potential use in differentiation therapy. <i>Materials and Methods</i>: The potential of IL-6 signaling elicitors in differentiation therapy were examined by assessing changes in biomarker levels, the rate of cell proliferation, and tumorigenicity, respectively. <i>Results</i>: Enhanced IL-6 signaling could effectively induce C6 glioma cell differentiation, as determined by observed variations in the expression of differentiation, cell cycle, and stem cell biomarkers. Additionally, the total cell population and the tumorigenicity of glioma cells were all considerably reduced after TNF-α/IL-6/sIL-6R treatment. <i>Conclusions</i>: Our findings provide evidence that enhanced IL-6 signaling can efficiently promote tumorigenic C6 glioma cells to undergo differentiation.

Luís Felipe Amorim, Marcelo Marinho, Suzana Sampaio

Information technology (IT) organizations are increasing the use of agile practices, which are based on a people-centred culture alongside the software development process. Thus, it is vital to understand the social and human factors of the individuals working in agile environments, such as happiness and unhappiness and how these factors impact this kind of environment. Therefore, five case-studies were developed inside agile projects, in a company that values innovation, aiming to identify how (un)happiness impacts software engineers in agile environments. According to the answers gathered from 67 participants through a survey, interviews and using a cross-analysis, happiness factors identified by agile teams were effective communication, motivated members, collaboration among members, proactive members, and present leaders.