Julian Frattini, Richard Torkar, Robert Feldt
et al.
Controlled experiments are a core research method in software engineering (SE) for validating causal claims. However, recruiting a sample of participants that represents the intended target population is often difficult or expensive, which limits the external validity of experimental results. At the same time, SE researchers often have access to much larger amounts of observational than experimental data (e.g., from repositories, issue trackers, logs, surveys and industrial processes). Transportability methods combine these data from experimental and observational studies to "transport" results from the experimental sample to a broader, more representative sample of the target population. Although the ability to combine observational and experimental data in a principled way could substantially benefit empirical SE research, transportability methods have - to our knowledge - not been adopted in SE. In this vision, we aim to help make that adoption possible. To that end, we introduce transportability methods, their prerequisites, and demonstrate their potential through a simulation. We then outline several SE research scenarios in which these methods could apply, e.g., how to effectively use students as substitutes for developers. Finally, we outline a road map and practical guidelines to support SE researchers in applying them. Adopting transportability methods in SE research can strengthen the external validity of controlled experiments and help the field produce results that are both more reliable and more useful in practice.
This paper gives an overview about aspects of mechanical engineering of undulators. It is based mainly on two types that are used in the SwissFEL facility. The U15 Undulator is an example of an in-vacuum type and the UE38 is an APPLE-X type. It describes the frame, the adjustment of the magnets with flexible keepers and the adjustment of the whole device with eccentric movers.
Modern engineering design platforms excel at discipline-specific tasks such as CAD, CAM, and CAE, but often lack native systems engineering frameworks. This creates a disconnect where system-level requirements and architectures are managed separately from detailed component design, hindering holistic development and increasing integration risks. To address this, we present the conceptual framework for the GenAI Workbench, a Model-Based Systems Engineering (MBSE) environment that integrates systems engineering principles into the designer's workflow. Built on an open-source PLM platform, it establishes a unified digital thread by linking semantic data from documents, physical B-rep geometry, and relational system graphs. The workbench facilitates an AI-assisted workflow where a designer can ingest source documents, from which the system automatically extracts requirements and uses vision-language models to generate an initial system architecture, such as a Design Structure Matrix (DSM). This paper presents the conceptual architecture, proposed methodology, and anticipated impact of this work-in-progress framework, which aims to foster a more integrated, data-driven, and informed engineering design methodology.
This lecture presents an overview of the basic concepts and fundamentals of Engineering Materials within the framework of accelerator applications. After a short introduction, main concepts relative to the structure of matter are reviewed, like crystalline structures, defects and dislocations, phase diagrams and transformations. The microscopic description is correlated with physical properties of materials, focusing in metallurgical aspects like deformation and strengthening. Main groups of materials are addressed and described, namely, metals and alloys, ceramics, polymers, composite materials, and advanced materials, where brush-strokes of tangible applications in particle accelerators and detectors are given. Deterioration aspects of materials are also presented, like corrosion in metals and degradation in plastics.
Habitat quality (HQ) is a critical factor for regional ecosystem health and sustainable development, as well as an important basis for formulating ecological protection and land-use planning. The Qin-Mang River Basin, as an integral part of the biodiversity conservation area in the Yellow River Basin, plays a significant role in maintaining the balance and stability of the regional ecosystem. This study is based on land use/land cover changes (LUCC) data from 1992, 2002, 2012, and 2022. It employs a land use transfer matrix to analyze the dynamic trends and patterns of LUCC. HQ changes are evaluated using the InVEST model, and the GeoDetector model is used to identify the key driving factors and their interactions. Additionally, spatial autocorrelation analysis is applied to explore the spatial clustering characteristics of HQ. The results indicate that between 1992 and 2022, the cumulative area of land transfer in the study area exceeded 600 km2, primarily characterized by the conversion of cultivated land to built-up areas. The HQ index decreased from 0.3409 in 1992 to 0.2896 in 2022, with a significant increase in spatial heterogeneity. Altitude, vegetation coverage, temperature, precipitation, and slope are the main driving factors influencing HQ, with natural factors dominating, but human activities gradually playing an increasingly significant role. Furthermore, HQ exhibits significant spatial clustering characteristics, with hotspot and coldspot areas providing scientific evidence for ecological protection and restoration measures. To improve HQ, it is recommended to strictly enforce ecological protection red lines, control the expansion of built-up areas, improve ecological compensation mechanisms, and promote ecological restoration measures such as returning farmland to forest and grassland.
Abstract Determining the extent of tunnel loosening zones is a crucial factor in establishing reasonable support parameters. Addressing the challenge of testing tunnel loosening zones, this study focused on the Dongmachang Tunnel No. 1. Seismic wave methods are employed to test the tunnel’s surrounding rock loosening zones. The results are processed using the reflection wave method, and the average wave velocity method is proposed as a standard for determining the loosening zone range. Subsequently, the surface wave method is utilized to process seismic wave data, validating the accuracy of the seismic wave method. Furthermore, a more precise range of the surrounding rock loosening zone is determined based on single hole acoustic method, and theoretical calculations. The obtained results align with the loosening zone range as determined by the average wave velocity method. Finally, a novel high-performance concrete lining structure is introduced for rehabilitating tunnel sections with significant deformations. The effectiveness of this new high-performance concrete lining structure is investigated through numerical simulations and on-site application. The study outcomes present new methodologies and technological support for determining tunnel surrounding rock loosening zones.
Hybrid organic-inorganic materials have been considered as a new candidate in the field of thermoelectric materials from the last decade due to their great potential to enhance the thermoelectric performance by utilizing the low thermal conductivity of organic materials and the high Seebeck coefficient, and high electrical conductivity of inorganic materials. Herein, we provide an overview of interfacial engineering in the synthesis of various organic-inorganic thermoelectric hybrid materials, along with the dimensional design for tuning their thermoelectric properties. Interfacial effects are examined in terms of nanostructures, physical properties and chemical doping between the inorganic and organic components. Several key factors which dictate the thermoelectric efficiency and performance of various electronic devices are also discussed, such as the thermal conductivity, electric transportation, electronic band structures, and band convergence of the hybrid materials.
Wolf-Peter Schill is Deputy Head of the Energy, Transportation, Environment Department at the German Institute for Economic Research (DIW Berlin), where he leads the research area Transformation of the Energy Economy. He engages in open-source power sector modeling, which he applies to economic analyses of renewable energy integration, energy storage, and sector coupling. He holds a diploma in environmental engineering and a doctoral degree in economics from Technische Universitat Berlin.
In recent years, open-pit mining has seen significant advancement, the cooperative operation of various specialized machinery substantially enhancing the efficiency of mineral extraction. However, the harsh environment and complex conditions in open-pit mines present substantial challenges for the implementation of autonomous transportation systems. This research introduces a novel paradigm that integrates Scenario Engineering (SE) with autonomous transportation systems to significantly improve the trustworthiness, robustness, and efficiency in open-pit mines by incorporating the four key components of SE, including Scenario Feature Extractor, Intelligence and Index (I&I), Calibration and Certification (C&C), and Verification and Validation (V&V). This paradigm has been validated in two famous open-pit mines, the experiment results demonstrate marked improvements in robustness, trustworthiness, and efficiency. By enhancing the capacity, scalability, and diversity of autonomous transportation, this paradigm fosters the integration of SE and parallel driving and finally propels the achievement of the '6S' objectives.
Global Navigation Satellite Systems (GNSS) aided Inertial Navigation System (INS) is a fundamental approach for attaining continuously available absolute vehicle position and full state estimates at high bandwidth. For transportation applications, stated accuracy specifications must be achieved, unless the navigation system can detect when it is violated. In urban environments, GNSS measurements are susceptible to outliers, which motivates the important problem of accommodating outliers while either achieving a performance specification or communicating that it is not feasible. Risk-Averse Performance-Specified (RAPS) is designed to optimally select measurements to address this problem. Existing RAPS approaches lack a method applicable to carrier phase measurements, which have the benefit of measurement errors at the centimeter level along with the challenge of being biased by integer ambiguities. This paper proposes a RAPS framework that combines Real-time Kinematic (RTK) in a tightly coupled INS for urban navigation applications. Experimental results demonstrate the effectiveness of this RAPS-INS-RTK framework, achieving 85.84% and 92.07% of horizontal and vertical errors less than 1.5 meters and 3 meters, respectively, using a smartphone-grade Inertial Measurement Unit (IMU) from a deep-urban dataset. This performance not only surpasses the Society of Automotive Engineers (SAE) requirements, but also shows a 10% improvement compared to traditional methods.
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.
Tunnels for subways and railways are a vital part of urban transportation systems, where shield tunneling using assembled segmental linings is the predominant construction approach. With increasing operation time and varying geological conditions, shield tunnels usually develop defects that compromise both structural integrity and operational safety. One common issue is the separation of segment joints that may cause water/mud penetration and corrosion. Existing inspection strategies can only detect openings after their occurrence, which cannot provide early warnings for predictive maintenance. To address this issue, this work proposes a multi-point seam contact pressure monitoring method for joint opening identification. It first derived the theoretical correlation between contact pressure distribution and segment opening; then, a finite element model was established to explore the stress and deformation responses under combined axial and bending loads. Finally, multi-point piezoelectric film sensors were implemented on a scaled segment model to validate the theoretical and numerical analyses. Results indicate that the multi-point monitoring method can effectively identify opening amounts at the segment joints with an average error of 8.8%, confirming the method’s feasibility. These findings support the use of this monitoring technique for early detection and assessment of joint openings in shield tunnels.
This paper presents an experimental and numerical investigation into the bending behaviour of reinforced concrete (RC) T-beams damaged by overheight vehicle impact strengthened with ultra-high performance concrete (UHPC). Four-point bending tests were conducted on one RC T-beam and six UHPC-strengthened RC T-beams, and the primary parameters included the length and thickness of the UHPC strengthening layer, as well as the filling area of UHPC for the damaged region. The test results demonstrated that the UHPC strengthening layer effectively delayed the development of concrete cracks, improved the bending stiffness, cracking load, and resistance of the T-beams. The UHPC-strengthened T-beams exhibited an increase in cracking and ultimate loads by 39–339 % and 26–113 %, respectively, compared to the RC T-beam. Subsequently, a finite element (FE) model of the UHPC-strengthened T-beams was developed and validated using the experimental results. A parametric study using the validated FE model was conducted, revealing that insufficient strengthened length or excessive strengthened thickness of the UHPC layer increased the risk of debonding failure. Furthermore, for T-beams experiencing bending failure, increasing the thickness and height of the UHPC layer, as well as the UHPC filling area for the damaged region, significantly improved the bending resistance, while the UHPC layer length had little effect on the bending resistance. Finally, based on the calculation theory of RC beams under bending loads and considering the strain-hardening behaviour of UHPC in tension, a design method for the bending resistance of damaged RC T-beams strengthened with UHPC was proposed and verified using the experimental and numerical results.
Materials of engineering and construction. Mechanics of materials
Mujahid Ali, Elżbieta Macioszek, Kennedy Onyelowe
et al.
Physical activity (PA) has the feasibility to enhance health parameters; however, the intensity such as frequency (days/week) and duration (minutes/day) are yet to be investigated. The current study aims to mediate the relationship between spatial–temporal variables and health via physical activity intensity (PAI) to reduce GHG emissions and promote a healthier society, and sustainable transportation system. A consecutive 21-day comprehensive dataset comprising 191 households, and 732 individuals was gathered and analyzed using multi-level linear regression analysis and a hierarchical structural equation model. The statistical analysis revealed that all dependent variables had R2 greater than 20 %. A unit increase in strenuous intensity PA is positively correlated with physical health and social health by 2.1 % and 0.3 %, indicating that PAI acts as a mediator in the link between daily activities and health outcomes. Age, gender, occupation, and income enormously impact transport mode choice – males, aged 23–45, workers, and high-income households are more dependent on motorized transport while females, over 55, non-workers, and low-income are highly dependent on non-motorized and public transport.