Computational Object-Wrapping Rope Nets

Wrapping objects using ropes is a common practice in our daily life. However, it is difficult to design and tie ropes on a 3D object with complex topology and geometry features while ensuring wrapping security and easy operation. In this article, we propose to compute a rope net that can tightly wrap around various 3D shapes. Our computed rope net not only immobilizes the object but also maintains the load balance during lifting. Based on the key observation that if every knot of the net has four adjacent curve edges, then only a single rope is needed to construct the entire net. We reformulate the rope net computation problem into a constrained curve network optimization. We propose a discrete-continuous optimization approach, where the topological constraints are satisfied in the discrete phase and the geometrical goals are achieved in the continuous stage. We also develop a hoist planning to pick anchor points so that the rope net equally distributes the load during hoisting. Furthermore, we simulate the wrapping process and use it to guide the physical rope net construction process. We demonstrate the effectiveness of our method on 3D objects with varying geometric and topological complexity. In addition, we conduct physical experiments to demonstrate the practicability of our method.

Realization of Super-Large-Diameter Slurry Shield Passing through Settlement-Sensitive Area Based on Unreinforced Disturbance Control Technology

Due to the complex construction conditions of shield tunnels, ground disturbance is inevitable during the construction process, which leads to surface settlement and, in serious cases, damage to surrounding buildings (structures). Therefore, it is especially important to effectively control the constructive settlement of subway tunnels when crossing settlement-sensitive areas such as high-density shantytowns. Based on the project of Wuhan Metro Line 8 Phase I, the shield of Huangpu Road Station-Xujiapang Road Station interval crossing high-density shantytowns, we study the disturbance control technology of oversized diameter mud and water shield crossing unreinforced settlement-sensitive areas during the construction process. By optimizing the excavation parameters and evaluating the ground buildings, the excavation process can be monitored at the same time, and the water pressure, speed, and tool torque required during the excavation during the construction process can be finely adjusted; the control of tunneling process parameters can provide reference and basis for analyzing the construction control of large-diameter shield through old shantytowns.

BIM Approach in Construction Safety—A Case Study on Preventing Falls from Height

The construction industry has one of the highest occupational accident incidence rates among all economic sectors. Currently, building information modelling (BIM) appears to be a valuable tool for analysing occupational safety issues throughout the construction life cycle of projects, helping to avoid hazards and risks and, consequently, increasing safety. This work investigates BIM methodology and the application of related technologies for building safety planning and demonstrates the potential of this technology for the integrated implementation of safety measures during the design phase and construction site management. The first step consisted of a literature review on applying BIM-related technologies for safety in the design and planning phases. Following this, to show the potentialities of construction simulation, a case study based on BIM 4D to prevent falls from height was developed. With BIM 4D, it is possible to follow the construction process over time, giving the construction safety technicians, designers, supervisors and managers the capability to analyse, in each phase, the potential risks and identify which safety measures should be implemented. BIM can effectively integrate safety measures from the design phase to the construction and use phase and enable integrated safety planning within construction planning, leading to reliable safety management throughout the construction process.

Meaning Making with Multiple Representations: a Case Study of a Preservice Teacher Creating a Digital Explanation

The construction of dynamic multimedia products requires the selection and integration of a range of semiotic resources. As an assessment task for preservice teachers, this construction process is complex but has significant potential for learning. To investigate how weaving together multiple representations in such tasks enables learners to develop conceptual understanding, the paper presents an indicative case study of a 2nd-year preservice primary (K-6) teacher who created a digital explanation on the topic of ‘transparency’ for stage 3 children (ages 11–12). We focus on data gathered during the 3-h construction process including artefacts such as images, online searches, websites accessed and paper records used for planning; the digital explanation as product; audio and video capture of the construction process and pre- and post-construction interviews. Using multimodal analysis, we examine these data to understand how meanings are negotiated as the maker moves iteratively among multiple representations and through semiotic choices within these representations to explain the science concept. The analyses illustrate the complexity of the construction process while providing insight into the creator’s decision-making and to her developing semiotic and conceptual understandings. These findings allow us to build on the concept of cumulative semiotic progression (Hoban & Nielsen, Research in Science Education, 35, 1101-1119, 2013) by explicating the role of iterative reasoning in the production of pedagogic multimedia.

A trusted de-swinging k-anonymity scheme for location privacy protection

K-anonymity has been gaining widespread attention as one of the most widely used technologies to protect location privacy. Nevertheless, there are still some threats such as behavior deception and service swing, since utilizing distributed k-anonymity technology to construct an anonymous domain. More specifically, the coordinate of the honest node will be a leak if the malicious nodes submit wrong locations coordinate to take part in the domain construction process. Worse still, owing to service swing, the attacker increases the reputation illegally to deceive honest nodes again. To overcome those drawbacks, we propose a trusted de-swinging k-anonymity scheme for location privacy protection. Primarily, we introduce a de-swinging reputation evaluation method (DREM), which designs a penalty factor to curb swinging behavior. This method calculates the reputation from entity honesty degree, location information entropy, and service swing degree. Besides, based on our proposed DREM, a credible cloaking area is constructed to protect the location privacy of the requester. In the area, nodes can choose some nodes with a high reputation for completing the construction process of the anonymous domain. Finally, we design reputation contracts to calculate credit automatically based on smart contracts. The security analysis and simulation results indicate that our proposed scheme effectively resists malicious attacks, curbs the service swing, and encourages nodes to participate honestly in the construction of cloaking areas.

Spatiotemporal Deformation of Existing Pipeline Due to New Shield Tunnelling Parallel Beneath Considering Construction Process

In this paper, we study the effects of the shield tunnel construction on the deformation of an existing pipeline parallel to and above the new shield tunnel. We propose an analytical solution to predict the spatiotemporal deformation of the existing pipeline and consider different force patterns of the shield tunnelling, i.e., ground volume loss, support pressure, frictional force, and torsional force. The proposed method is validated by the monitoring data of Subway Line 3 of Nanchang and provides a reasonable estimation of the pipeline’s deformation. The parametric analyses are performed to study the influences on the pipeline’s deformation. The main advantage of our paper is that the spatiotemporal characteristics of the existing pipeline’s deformation are analysed, providing longitudinal deformation curve (LDC), deformation development curve (DDC), and grouting reinforcement curve (GRC). Compared with the perpendicular undercrossing project, both LDC and DDC have the same profiles and maximum values and move forward as a whole with the shield tunnel advance. Thus, the spatiotemporal deformation of the overall pipeline can be extrapolated from the deformation of two known points on the pipeline. The spatiotemporal characteristic curves combined with LDC, DDC, and GRC can suggest feasible, effective, and economical construction and grouting schemes to control the pipeline’s deformation after the deformation control standards have been determined.

Might and might not: Children's conceptual development and the acquisition of modal verbs

When a child acquires her first modal verbs, is she learning how to map words in the language she is learning onto innate concepts of possibility, necessity, and impossibility? Or does she also have to construct modal concepts? If the concepts are constructed, does learning to talk about possibilities play a role in the construction process? Exploring this hypothesis space requires testing children's acquisition of modal vocabulary alongside nonverbal tests of their modal concepts. Here we report a study with 103 children from 4;0 through 7;11 and 24 adults. We argue that the data fit best with the hypothesis that acquisition of modal language and development of modal concepts proceed hand-in-hand. However, more research is needed, especially with 3-year-olds.

From Norm Evaluation to Norm Construction

This study examines the issue of norm construction in al-Ghazālī’s thought focusing on the grounds advanced to support his radical infallibilist position. To fulfill such end, al-Ghazālī, I explain, relies on two types of arguments, the first one relates to the presumptive nature of legal texts in order to highlight their fundamental indeterminacy and the second links to the interpreter to show the impossibility to fall into error. To buttress these arguments, al-Ghazālī both draws on epistemological principles and metaethical ones. As it will be shown in the study, al-Ghazālī ultimately explains the divergence in interpretation of norms using the concept of ṭabʿ (nature, disposition or appetitive self) drawing on his well-known relativist ethical theory concerning norm evaluation and therefore brings in a unique way this typical feature of Ashʿarism within his own radical infallibilist theory of norm construction. The concept of ṭabʿ allows to bridge the gap between the ambiguity in the revealed text and the mujtahid’s interpretation in the norm construction process, and ultimately serves to justify ex post the choices made by the mujtahid. In doing so, al-Ghazālī assigns to theology a critical role in revealing the origin of the illusion of the jurists who naively think that licit and illicit are qualities of things themselves.

CO₂ emissions of an asphalt pavement in kg of CO₂ per m2

Climate change is one of the world's major problems and concerns the entire human population as its effects are global in scope. Climate change is driven by the greenhouse effect, which is generated by greenhouse gases (GHG). The construction industry is important in the development of a country, both economically and culturally, since it is through it that the infrastructure needs required for a nation's economic and social activities are met. Urban environments are composed of various structures that favor economic, social and any other activities of interest within the existing population; such urban environment is mainly connected by a system that is constituted by asphalt pavements of flexible or rigid type. This project analyzes the environmental impacts generated during the construction process of an asphalt pavement corresponding to the Real de Sevilla III subdivision, located in Obregon City, Sonora, Mexico, applying the Simapro 9.0 Software, obtaining a result of 12.618 Kg CO2 eq/m2 and 1,140, 863.493 Kg-CO2/fractionation generated by its main materials and activities and equipment consumptions.

Implementation of Visualization and Modeling Technologies for Transportation Construction

State departments of transportation (DOTs) increasingly use visualization and modeling technologies for delivering transportation projects across the United States. Advanced and innovative technologies have the ability to improve various construction processes and tasks while making the construction process more efficient and productive. Visualization and modeling technologies, which include building information modeling for infrastructure, light detection and ranging, virtual reality, and augmented reality, are becoming more commonplace in transportation construction. Yet, the use of these technologies varies among state DOTs. The intent of this study is to investigate the use of visualization and modeling technologies for transportation construction. This study employed a triangulation research methodology including an extensive literature review, survey questionnaire of DOTs, and seven case studies. Results of the study show that 92% of state DOTs use visualization and modeling technologies for construction. Then, 81% of DOTs use visualization and modeling technologies for constructability reviews, 38% use them for documentation of as-builts and simulating bridge and structure construction, and 35% use them for quality management, inspections, and monitoring progress of work. The main barriers to using visualization and modeling technologies include legal concerns with using digital models as contract documents, incompatibilities in software and hardware between the DOTs and contracted parties, and the appropriate knowledge, skills, and abilities required to use visualization and modeling technologies for construction. The findings from this study provides valuable information for state DOTs to approach their implementation and use of visualization and modeling technologies for transportation construction delivery.