Search Results (2,590)

This study explores the key considerations in designing a smart environment for the elderly, aiming to enhance their effective use of such space environments within a structure such as a building. A survey was conducted among a limited sample of elderly recipients in South Korea to explore the relationship between the frequency and usefulness of smart digitalization usage and various factors, including design elements, age, and perceived necessity. By identifying the needs of modern elderly people regarding smart environments, the study aims to provide implications for the direction of smart environments for the elderly, thereby contributing to the creation of a sustainable society in various ways. The study results are as follows. First, in terms of design factors, eco-friendliness was identified as a major factor influencing both the frequency of use and the convenience of the elderly in smart environments. Second, the age group of the elderly was found to be a significant variable affecting the frequency of use and the convenience of smart environments. Third, variables such as an emergency environment, a comfortable environment, and a healthy environment with regard to environmental factors, as well as maintenance, aesthetics, and safety in design elements, were found to have no statistically significant impact. These findings suggest that simply considering environmental friendliness or aesthetics is insufficient in designing a smart residential environment for the elderly, and that design strategies prioritizing the actual user experience and convenience are necessary. Full article

In rehabilitation, physicians plan lower-limb exercises via linear guidance. Ensuring efficacy and safety, they design patient-specific paths, carefully plotting smooth trajectories to minimize jerks. Replicating their precision in robotics is a major challenge. This study introduces a linear rehabilitation motion planning method designed for physicians to use a multi-posture lower-limb rehabilitation robot, encompassing both path and trajectory planning. By subdividing the lower limb’s action space into four distinct training sections and classifying this space, we articulate the correlation between linear trajectories and key joint rehabilitation metrics. Building upon this foundation, a rehabilitative path generation system is developed, anchored in joint rehabilitation indicators. Subsequently, high-order polynomial curves are employed to mimic the smooth continuity of traditional rehabilitation trajectories and joint motions. Furthermore, trajectory planning is refined through the resolution of a constrained quadratic optimization problem, aiming to minimize the abrupt jerks in the trajectory. The optimized trajectories derived from our experiments are compared with randomly generated trajectories, demonstrating the suitability of trajectory optimization for real-time rehabilitation trajectory planning. Additionally, we compare trajectories generated based on the two groups of joint rehabilitation indicators, indicating that the proposed path generation system effectively assists clinicians in executing efficient and precise robot-assisted rehabilitation path planning. Full article

In the realm of daily life, ensuring the safety of building structures and civil engineering projects remains a paramount research focus. The creep properties of materials significantly influence their long-term loading process. Specifically, creep load and creep time are pivotal factors that impact material creep damage, thereby playing a crucial role in assessing the safety of engineering endeavors and estimating aspects such as housing construction. This study undertakes creep damage tests on cement-based materials, subjecting them to varying creep loads and creep times, and subsequently conducts uniaxial compression tests on the specimens post-creep damage. The refined Nishihara model is employed for data fitting, facilitating the construction of a creep damage time-stress model. Concurrently, a Neural Network model is utilized to validate the experimental data. The findings indicate that both steady-state creep strain and steady-state creep rate exhibit discernible trends relative to creep load and creep time, effectively mirroring the alterations in creep damage experienced by the specimens. The refined Nishihara model proves adept at predicting and equating creep damage under diverse creep loads and creep times. Similarly, the trained Neural Network model demonstrates capability in measuring and estimating various creep damages. The study successfully explored the correlation between creep time and creep load, enabling the simulation of long-term creep damage within a shorter creep time and facilitating an analysis of its physical and mechanical properties, which is pivotal in predicting the safety of large-scale engineering projects. Concurrently, it advances research on material damage equivalence, offering insights and theoretical groundwork for developing a system to assess material damage equivalence under various damage conditions. Full article

Unlike traditional building structures, transmission tower foundations endure significant vertical and horizontal loads, with particularly high uplift resistance requirements in complex terrains. Moreover, challenges such as difficult material transport and low construction efficiency arise in these regions. This study, based on practical projects, proposes a novel high uplift resistance prestressed concrete prefabricated foundation (HURPCPF) tailored for transmission line systems in complex terrains. A refined finite element model is developed using ABAQUS to analyze its performance under uplift, compressive, and horizontal loads. Comparative studies with cast-in-situ concrete foundations evaluate the HURPCPF’s bearing capacity, while parametric analysis explores the impacts of foundation depth and dimensions. The results show that the proposed HURPCPF exhibits a linear load–displacement relationship, with uniform deformation and good integrity under compressive and uplift conditions. During overturning, the tilt angle is less than 1/500, meeting safety standards. The design of prestressed steel strands and internal reinforcement effectively distributes tensile stress, with a maximum stress of 290 MPa, well below the yield stress of 400 MPa. Compared to cast-in-situ concrete foundations, the displacement at the top of the HURPCPF’s column differs by less than 7%, indicating comparable bearing performance. As foundation depth and size increase, vertical displacement of the HURPCPF decreases, enhancing its uplift resistance. Full article

As an important data source, the Building Information Model (BIM) plays an important role in modern building safety management. Numerous studies have closely examined automatic compliance inspections for building safety and the safety management of dangerous projects. However, the value of the BIM has not been fully exploited in evidence-based practices of building safety. To address this limitation, this paper proposes an ontology-based Evidence/Risk-Based Safety (ERBS) management framework for divisional and subdivisional works with high risk, which includes: (1) BIM data extraction based on dynamo; (2) creation of an ontology based on building information and the ERBS management process model; (3) converting BIM data and evidence into ontology individuals; and (4) integrating the ontology through semantic web technology and using the Semantic Web Rule Language (SWRL) to conduct rule-based reasoning on the ontology. A case study shows that the framework is effective for the ERBS management of divisional and subdivisional works with high risk. The framework proposed in this study provides effective safety management methods for high-risk projects that can be applied in wider engineering practice in the future. Full article

During the long-term operation of hydraulic structures under the action of complex loads and impacts, non-design changes occur, which lead to a decrease in the bearing capacity and safety and, accordingly, to the need for structural reinforcements. Experiments were conducted to study the strengthening of reinforced concrete models of hydraulic structures with interblock construction joints (located in two directions) and with the low longitudinal reinforcement coefficients typical of hydraulic structures (μ_s = 0.0039 and μ_s = 0.0083), using the low concrete classes B15 and B25. These structures were strengthened using external reinforcement with carbon ribbons of the FibArm 530/300 type. The results revealed an increase in the bearing capacity (by 1.355- and 1.66-fold); accordingly, the high efficiency of this strengthening method for reinforced concrete hydraulic structures was proven. Using the results of these experiments, including the obtained special characteristic of the cracking of reinforced concrete structures and the results of studies by other authors, recommendations for calculations involving reinforced concrete hydraulic engineering structures strengthened with an external reinforcement system of carbon-fibre-based composite materials were developed and proposed. Carbon-fibre-based composite materials are used as elements of external reinforcement for building structures (unidirectional—tapes, bidirectional—meshes and fabrics). The calculation recommendations proposed by the authors can be taken into account for the creation of a regulatory framework for hydropower facilities, including hydroelectric power plants and pumped-storage power plants. They justify the use of an external reinforcement system made with carbon-fibre-based composite materials to strengthen hydraulic structures in operation and provide an increased level of safety for reinforced concrete structures and constructions. Full article

The increasing demand for special education in architectural design highlights the urgent need to ensure the safe evacuation of students with intellectual disabilities. However, current research on classroom evacuation for these students remains limited, particularly concerning critical factors, such as the number, location, and distance of exits. This study investigated the impact of dependent behavior on classroom exit design for students with intellectual disabilities by developing a Cellular Automaton (CA) model based on their behavioral characteristics. Simulated evacuation scenarios, considering and disregarding dependent behaviors, were analyzed to assess their effects on the number and positioning of exits, and a predictive model was implemented to establish the relationship between exit spacing and evacuation time. The results indicated that the dependent behavior significantly reduced evacuation efficiency and substantially affected classroom exit design. Considering the dependent behavior, this study demonstrated that setting two exits reduced the average evacuation time for students with intellectual disabilities by 12.99%, with further reductions achieved by placing the exits at the rear rather than at the sides or front of the classroom. The research also revealed that under the influence of dependent behavior, the average evacuation time initially decreased and then increased as the distance between exits increased. As one of the few studies addressing evacuation issues for students and the first to incorporate dependent behavior into the evacuation model, this study provides valuable recommendations for classroom designs that balance evacuation safety and daily usability. It offers essential data to inform architectural designs for classrooms serving students with intellectual disabilities and serves as a reference for future educational building design standards and regulations. Full article

As an emerging technology, digital twin (DT) is increasingly valued in bridge management for its potential to optimize asset operation and maintenance (O&M). However, traditional bridge management systems (BMS) and existing DT applications typically rely on standalone building information modeling (BIM) or geographic information system (GIS) platforms, with limited integration between BIM and GIS or consideration for their underlying graph structures. This study addresses these limitations by developing an integrated DT system that combines WebGIS, WebBIM, and graph algorithms within a three-layer architecture. The system design includes a common data environment (CDE) to address cross-platform compatibility, enabling real-time monitoring, drone-enabled inspection, maintenance planning, traffic diversion, and logistics optimization. Additionally, it features an adaptive data structure incorporating JSON-based bridge defect information modeling and triple-based roadmap graphs to streamline data management and decision-making. This comprehensive approach demonstrates the potential of DTs to enhance bridge O&M efficiency, safety, and decision-making. Future research will focus on further improving cross-platform interoperability to expand DT applications in infrastructure management. Full article

Urban airspace, characterized by densely packed high-rise buildings, presents complex and dynamically changing environmental conditions. It brings potential risks to UAV flights, such as the risk of collision and accidental entry into no-fly zones. Currently, mainstream path planning algorithms, including the PSO algorithm, have issues such as a tendency to converge to local optimal solutions and poor stability. In this study, an improved particle swarm optimization algorithm (LGPSO) is proposed to address these problems. This algorithm redefines path planning as an optimization problem, constructing a cost function that incorporates safety requirements and operational constraints for UAVs. Stochastic inertia weights are added to balance the global and local search capabilities. In addition, asymmetric learning factors are introduced to direct the particles more precisely towards the optimal position. An enhanced Lévy flight strategy is used to improve the exploration ability, and a greedy algorithm evaluation strategy is designed to evaluate the path more quickly. The configuration space is efficiently searched using the corresponding particle positions and UAV parameters. The experiments, which involved mapping complex urban environments with 3D modeling tools, were carried out by simulations in MATLAB R2023b to assess their algorithmic performance. The results show that the LGPSO algorithm improves by 23% over the classical PSO algorithm and 18% over the GAPSO algorithm in the optimal path distance under guaranteed security. The LGPSO algorithm shows significant improvements in stability and route planning, providing an effective solution for UAV path planning in complex environments. Full article

With rapid economic development and a continuous increase in motor vehicle numbers, traffic congestion on highways has become increasingly severe, significantly impacting traffic efficiency and public safety. This paper proposes and investigates a traffic congestion prediction and emergency lane development strategy based on object detection algorithms. Firstly, the YOLOv11 object detection algorithm combined with the ByteTrack multi-object tracking algorithm is employed to extract traffic flow parameters—including traffic volume, speed, and density—from videos at four monitoring points on the Changshen Expressway in Nanjing City, Jiangsu Province, China. Subsequently, using an AdaBoost regression model, the traffic density of downstream road sections is predicted based on the density features of upstream sections. The model achieves a coefficient of determination $R^2$ of 0.968, a mean absolute error of 11.2 vehicles/km, and a root mean square error of 19.9 vehicles/km, indicating high prediction accuracy. Building on the interval occupancy rate model, this paper further analyzes the causes of traffic congestion and designs decision-making processes for the activation and deactivation of emergency lanes. By real-time monitoring and calculating the vehicle occupancy rate of the CD interval, threshold conditions for activating emergency lanes are determined. When the interval occupancy rate $K_{CD}(t)$ exceeds 80%, the emergency lane is proactively opened. This method effectively alleviates traffic congestion and reduces congestion duration. Quantitative analysis shows that after activating the emergency lane, the congestion duration in the CD section decreases from 58 min to 30 min, the peak occupancy rate drops from 1 to 0.917, and the congestion duration is shortened by 48.3%. Additionally, for the Changshen Expressway, this paper proposes two optimization points for monitoring point layout, including setting up monitoring points in downstream sections and in the middle of the CD section, to further enhance the scientific and rational management of emergency lanes. The proposed strategy not only improves the real-time extraction and prediction accuracy of traffic flow parameters but also achieves dynamic management of emergency lanes through the interval occupancy rate model, thereby alleviating highway traffic congestion. This has significant practical application value. Full article

With over 1.6 million traffic deaths in 2016, automated vehicles equipped with automated driving systems (ADSs) have the potential to increase traffic safety by assuming human driving tasks within the operational design domain (ODD). However, safety validation is challenging due to the open-context problem. Current strategies, such as pure driving and requirement-based testing, are insufficient. Scenario-based testing offers a solution but necessitates appropriate scenario selection, testing methods, and evaluation criteria. This paper builds upon a method to calculate the covered ODD using tested scenarios generated from logical scenarios, considering parameter discretisation uncertainty. Acceptance criteria for the safety argumentation are proposed based on parameter space coverage and variance introduced via discretisation, thus contributing to quantifying the residual risks of safety validation. The approach is demonstrated through two logical scenarios with probability density functions of the parameters generated using a trajectory dataset. These criteria can serve as risk acceptance criteria, providing comparability and explainable results. By developing a robust scenario-based testing approach, ADS safety can be validated, leading to increased traffic safety and reduced fatalities. Since ADSs incorporate AI models, this proposed validation strategy can be extended to AI systems across multiple domains for the respective assurance argument required for deployment. Full article

In recent years, reservoir flood control and dam safety have faced severe challenges due to changing environmental conditions and intense human activities. There has been a significant increase in the proportion of dam breaks caused by floods exceeding reservoir design levels. Dam breaks have periodically occurred due to flood overtopping, threatening people’s lives and properties. This highlights the importance of describing the challenges encountered in reservoir flood risk prevention and control under extreme climatic conditions and proposing strategies to safeguard reservoirs against floods and to protect downstream communities. This study conducts a statistical analysis of dam breaks resulting from floods exceeding reservoir design levels, revealing new risk indicators in these settings. The study examines recent representative engineering cases involving flood risks and reviews research findings pertaining to reservoir flood risks under extreme climatic conditions. By comparing flood prevention standards at typical reservoirs and investigating the problems and challenges associated with current standards, the study presents the challenges and strategies associated with managing flood risks in reservoirs under extreme climatic conditions. The findings show that the driving forces and their effects shaping flood risk characteristics in specific regions are influenced by atmospheric circulation and vegetative changes in underlying surfaces or land use. There is a clear increasing probability of dam breaks or accidents caused by floods exceeding design levels. Most dam breaks or accidents occur in small and medium-sized reservoirs, due to low flood control standards and poor management. Therefore, this paper recommends measures for improving the flood prevention capacity of these specific types of reservoirs. This paper proposes key measures to cope with floods exceeding reservoir design levels, to supplement the existing standard system. This includes implementing an improved flood standard based on dam risk level and the rapid reduction in the reservoir water level. To prevent breaks associated with overtopping, earth–rock dams should be designed to consider extreme rainfall events. More clarity is needed in the execution principles of flood prevention standards, and the effectiveness of flood calculations should be studied, adjusted, and validated. The research results provide better descriptions of flood risks in reservoirs under extreme climatic conditions, and the proposed strategies have both theoretical and practical implications for building resilience against flood risks and protecting people’s lives and properties. Full article

Acquiring knowledge of aircraft flight dynamics is crucial for simulation, control, mission performance and safety assurance analysis. In the fast-paced UAV market, long flight testing campaigns are hard to achieve, leaving limited controlled flight data and a significant amount of unplanned flight data. This work delves into the application of system identification techniques on unplanned flight data when faced with a shortage of dedicated flight test data. Based on a medium-sized, fixed-wing UAV, it focuses on the system identification of longitudinal dynamics using structural routine flight test data of pitch down and pitch up manoeuvres with no specific guidelines for the control inputs given. The proposed solution uses first- and second-order parameter-based models to build a non-linear dynamic model which, using a least square error optimisation algorithm in a time domain formulation, has its parameters tuned to converge the model behaviour with the real aircraft dynamics. The optimisation uses a combination of pitch, altitude, airspeed and pitch rate responses as a measure of model accuracy. Very significant improvements regarding the UAV model response are found when trimmed flight manoeuvres are used, resulting in proper estimation of important aerodynamic and control derivatives. Pitching moment and control derivatives are shown to be the crucial parameters. However, difficulties in estimation are shown for untrimmed flight manoeuvres. Better results were obtained when using multiple manoeuvres simultaneously in the optimisation error metric, as opposed to single manoeuvres that led to system bias. The proposed system identification procedure can be applied to any fixed-wing UAV without the need for specific flight testing campaigns. Full article

Due to the increasing number of vehicles and the limited land supply, old residential areas generally face parking difficulties. An intelligent parking service is a critical study direction to address parking difficulty since it can achieve the automatic management of parking processes and planning of parking spaces. However, the existing intelligent parking service systems have shortcomings such as low information quality, low management efficiency, and single service mode. To address the shortcomings, in this paper, we conduct a systematic study on utilizing digital twin (DT) technology to improve the intelligent parking service system. The main contributions are threefold: (1) We analyze the function requirements of the intelligent parking service for old residential areas, such as visual monitoring, refined management, and simulation optimization. (2) We design a DT-based intelligent parking service system by collecting data on physical parking space, constructing the corresponding virtual parking space, and building the user interaction platform. An old residential area in Guangzhou, China is used as a use case to show that the designed parking service system can meet the function requirements. (3) Through mathematical modeling and simulation evaluation, we utilize two typical intelligent parking services including dynamic parking planning and driving safety assessment to demonstrate the effectiveness of the proposed system. This study provides innovative solutions for parking management in old residential areas, utilizing DT technology to not only improve information quality and management efficiency, but also provide a theoretical basis and practical reference for the intelligent transformation of urban parking services. Full article

In this study, shear-critical reinforced concrete (RC) beams were strengthened by combining the prestressing and near-surface mounted (NSM) rods approaches. The potential danger of failure in such RC beams is a substantial concern as it is considered a potential threat. This study addresses its careful mitigation through experimental identification and numerical analysis to enhance the safety and sustainability of buildings by reducing the probability of failure risk for these RC beams. Nine of the ten RC beams that were tested had strengthened, and one had not. Internal prestressing (IP) within the beam body, external prestressing NSM (PNSM), internal embedment (IE) inside the beam with or without prestressing, and NSM are the strengthening technologies that were employed. The range of the extra shear reinforcement ratios (μs) was 0.87% to 1.60%. We investigated how strengthened beams behaved structurally in terms of the cracking load, ultimate load, load–deflection response, ultimate deflection, and stiffness. The insertion of five pairs of PNSM rods (μs = 1.45%) and five pairs of IP rods (μs = 1.6%), respectively, increased the beams’ shear capacity by 57.8% and 70.4%. Shear capacity increased by 23.2% when three pairs of IE rods (μs = 1.02%) were installed. The prestressing location had an impact on shear capacity, with the interior case surpassing the external one. Compared to the control, the stiffness of the strengthened beams rose by 20%, 82%, and 84.4% when three, four, or five pairs of internal prestressing rods were added. A formula is proposed to calculate the shear capacity of all beams strengthened using various methods. Full article