Construction Of Nets Research Articles

Construction of diverse adaptive camouflage nets based on soluble yellow-to-green switching electrochromic materials

The potential application of electrochromic (EC) materials and devices as adaptive camouflage in diverse environments requires further investigation. In this study, we aimed to enhance the camouflage effect of electrochromic devices (ECDs) by developing innovative EC camouflage nets. Three soluble EC materials (FTP, FEP and FBP) were synthesized by incorporating phenothiazine and ProDOT with different donors through direct(hetero) arylation polymerization. Due to the fine-tuning of the energy gap, the three materials exhibit yellow, yellowish-brown and reddish-brown colors in their neutral states, respectively. Particularly, FTP and FEP can switch between different yellow-to-green with superior EC performance. Furthermore, FTP-PEDOT and FEP-PEDOT ECDs were constructed. Notably, the FEP-PEDOT ECD demonstrated enhanced EC performance, characterized by a more noticeable yellow-to-green switch, faster switching times and improved cycle stability. To meet the adaptability for multi-environmental camouflage and wearable applications, we created diverse camouflage patterns using the mask-spray technique and developed three types (“stripe”/ “cross stripe”/ “block”) camouflage net ECDs. This study offers a comprehensive approach for developing adaptive camouflage nets tailored to diverse real combat settings.

Impacts on Embankments, Rigid and Flexible Barriers Against Rockslides: Model Experiments vs. DEM Simulations

AbstractAs a result of climate change, rockfalls and rock avalanches as well as landslides lead to an increasing hazard for settlement areas and infrastructures. The hazards of such mass movements mean that numerous protective structures must be planned and built. In addition to building such constructions, the refurbishment of existing protective structures is also playing an increasingly important role. Some of these protective structures are rigid structures consisting of concrete and/or steel elements. Due to the difficult accessibility, flexible net constructions are often considered. Embankment constructions are normally erected to protect against large mass movements. The choice of the right type of construction is based not only on geotechnical and geographical conditions, but also on the occurring energies and the impact of rockslides on the protective structure. In this study, small-scale laboratory experiments with different protective structures are presented. Rigid and flexible structures as well as reinforced embankments are investigated. Based on the results of the experiments, the impacts and deformations are recalculated numerically using the discrete element method (DEM). From the small-scale laboratory experiments and numerical simulations, the differences regarding the construction type of the protective structure can be investigated. An essential main point concerns the relationship between the flexibility of the barrier and the total impact load. The presented work is limited to the investigation of strongly fragmented gravitational mass movements such as rock avalanches.

Specifications and net construction of tilapia nets in Rawa Pening Lake

Specifications and net construction of tilapia nets in Rawa Pening Lake

Construction of Deep ReLU Nets for Spatially Sparse Learning.

Training an interpretable deep net to embody its theoretical advantages is difficult but extremely important in the community of machine learning. In this article, noticing the importance of spatial sparseness in signal and image processing, we develop a constructive approach to generate a deep net to capture the spatial sparseness feature. We conduct both theoretical analysis and numerical verifications to show the power of the constructive approach. Theoretically, we prove that the constructive approach can yield a deep net estimate that achieves the optimal generalization error bounds in the framework of learning theory. Numerically, we show that the constructive approach is essentially better than shallow learning in the sense that it provides better prediction accuracy with less training time.

Methods and Applications of Safety Control for Cable Net Structure Considering Spatiotemporal Changes

The construction of cable net structures is intricate, and the construction process itself is laborious. Conventional safety control measures during the construction of cable net structures involve monitoring cable forces and deformations at specific moments during the construction steps. However, these measures do not guarantee adequate safety assurance. This paper proposes a method for the safety control of cable net structures, considering spatiotemporal changes, based on the concept of digital twins. This method enables real-time monitoring and control of the cable net construction process onsite, facilitating a comparative analysis between the mechanical and geometric information of the construction site and the real-time finite element simulation results. Such an approach ensures safety control throughout the construction process. Firstly, a twin model framework for safety control is established. Then, the methods for spatiotemporal representation, data collection, and processing at the construction site are analyzed. Finally, the proposed method is validated through its application to the Xiaotian Cultural and Sports Park project. The results demonstrate that this method can achieve real-time monitoring and control of cable net structure construction.

Host-graph-sensitive RETE nets for incremental graph pattern matching with nested graph conditions

BackgroundEfficient querying of large graph structures is a problem at the heart of several application domains such as social networks and model driven engineering. In particular in the context of model driven engineering, where the same query is executed frequently over an evolving graph structure, incremental techniques based on RETE nets are a popular solution. However, the construction of adequate RETE nets for a specific problem instance is a challenge in and of itself. MethodsIn this article, we propose an approach to RETE net construction for queries in the form of graph patterns equipped with nested graph conditions that considers not only the structure of the query, but also the structure of the host graph to improve the net's performance regarding execution time and memory consumption. Furthermore, we suggest a technique for adapting the net structure to changing host graph characteristics. We evaluate the presented concepts empirically based on queries and data from two independent benchmarks, using a mature tool for incremental graph pattern matching as a reference. ResultsOur evaluation results indicate that considering host graph structure during RETE net construction can improve performance of the resulting net. The experiments also demonstrate that adapting the net structure to changing host graph characteristics can be performed with an acceptable execution time overhead for our examples and may yield more adequate RETE nets. Overall, our approach never performed worse than the reference by more than factor 1.2 regarding execution time and achieved an improvement by up to factor 20.

Manufacturing Maps, a Novel Tool for Smart Factory Management Based on Petri Nets and Big Data Mini-Terms

This article defines a new concept for real-time factory management—manufacturing maps. Manufacturing maps are generated from two fundamental elements, mini-terms and Petri nets. Mini-terms are sub-times of a technical cycle, the time it takes for any component to perform its task. A mini-term, by definition, is a sub-cycle time and it would only make sense to use the term in connection with production improvement. Previous studies have shown that when the sub-cycle time worsens, this indicates that something unusual is happening, enabling anticipation of line failures. As a result, a mini-term has dual functionality, since, on the one hand, it is a production parameter and, on the other, it is a sensor used for predictive maintenance. This, combined with how easy and cheap it is to extract relevant data from manufacturing lines, has resulted in the mini-term becoming a new paradigm for predictive maintenance, and, indirectly, for production analysis. Applying this parameter using big data for machines and components can enable the complete modeling of a factory using Petri nets. This article presents manufacturing maps as a hierarchical construction of Petri nets in which the lowest level network is a temporary Petri net based on mini-terms, and in which the highest level is a global view of the entire plant. The user of a manufacturing map can select intermediate levels, such as a specific production line, and perform analysis or simulation using real-time data from the mini-term database. As an example, this paper examines the modeling of the 8XY line, a multi-model welding line at the Ford factory in Almussafes (Valencia), where the lower layers are modeled until the mini-term layer is reached. The results, and a discussion of the possible applications of manufacturing maps in industry, are provided at the end of this article.

THE PHYSICAL MODEL FOR THE IL PAVILION AND THE USAGE OF ITS DIGITAL TWIN

The so-called IL pavilion in Stuttgart, constructed by Frei Otto and the Institute for Lightweight Structures (IL) served itself as an experimental building for testing the execution of a new type of cable net construction. At this 1:1 mock-up various manufacturing techniques and measuring methods were tested, additionally to model tests on physical models. These models were necessary, because at that time no adequate calculation methods were available to design the complex geometries of such wide-span cable net constructions. In this paper, the authors clarify the way the model was produced, the development of the measurement methods and the impact of model testing for the execution of the innovative construction of the German pavilion for the World's Fair in Montréal in 1967. The physical model, which is one of the few surviving measurement models from this period, was digitally rebuilt with state of the arts methods in the context of the DFG research project “last witnesses”. The data extracted from the physical model was compared with a model generated from the original cut stencils. Overall, the numbers match fairly well, nevertheless there are some outliers due to the changed numbers of elements, which have a deviation of more than 40%. The data extracted from the digital twin will further be used to evaluate changed boundary conditions, increased snow loads or wind effects for the building itself and to record the actual state of the model for future preservation measures.

THE PHYSICAL MODEL FOR THE IL PAVILION AND THE USAGE OF ITS DIGITAL TWIN

The so-called IL pavilion in Stuttgart, constructed by Frei Otto and the Institute for Lightweight Structures (IL) served itself as an experimental building for testing the execution of a new type of cable net construction. At this 1:1 mock-up various manufacturing techniques and measuring methods were tested, additionally to model tests on physical models. These models were necessary, because at that time no adequate calculation methods were available to design the complex geometries of such wide-span cable net constructions. In this paper, the authors clarify the way the model was produced, the development of the measurement methods and the impact of model testing for the execution of the innovative construction of the German pavilion for the World's Fair in Montréal in 1967. The physical model, which is one of the few surviving measurement models from this period, was digitally rebuilt with state of the arts methods in the context of the DFG research project “last witnesses”. The data extracted from the physical model was compared with a model generated from the original cut stencils. Overall, the numbers match fairly well, nevertheless there are some outliers due to the changed numbers of elements, which have a deviation of more than 40%. The data extracted from the digital twin will further be used to evaluate changed boundary conditions, increased snow loads or wind effects for the building itself and to record the actual state of the model for future preservation measures.

Dependence properties of scrambled Halton sequences

In this paper, scrambled Halton sequences are shown to have a form of negative dependence that is desirable for the purpose of improving upon the Monte Carlo method for multivariate integration. The scrambling methods with these properties are based on either the nested uniform permutations of Owen or the random linear scrambling of Matoušek. The framework of negative dependence is also used to develop new criteria for assessing the quality of generalized Halton sequences, in such a way that they can be analyzed for finite (potentially small) point set sizes and be compared to digital net constructions. Using this type of criteria, parameters for a new generalized Halton sequence are derived. Numerical results are presented to compare different generalized Halton sequences and their randomizations.

Crash tests to evaluate the design of temporary traffic control devices for increased safety of cyclists at road works

In Sweden there is an on-going process to formulate a national standard regulating the design of temporary traffic control devices used on pedestrian and bicycle paths. This paper presents results from simulated single-bicycle crashes with the purpose to create an understanding of how different features of such devices affect the risk of injuries among cyclists. A Hybrid II 50th percentile crash test dummy was placed in the saddle of a bicycle and crash tests, usually at 25 km/h, were performed. Eleven different types of road equipment were included, and different crash angles were applied, in a total of over 50 crash tests. The road equipment represented temporary traffic control devices of various kind commonly used in Sweden, but also some specifically designed for cyclists. The tests were documented with several video cameras at different angles. Slow motion pictures were analyzed with focus on mechanisms during impact and the following motion of the bicycle and the dummy. Observations regarding “body parts” in contact with the road equipment were of particular interest highlighting design features of importance such as height, smoothness of surfaces and energy-absorbing capacity. The tests show that all bicycle crashes into road equipment can cause injuries and thus the use of work zone material on bicycle paths should be avoided, if possible. Safety barriers designated to prevent cyclists from falling into a shaft must be high enough to do so and be anchored and linked together correctly to prevent them from falling and creating dangerous situations. Temporary traffic control devices should be flexible or energy-absorbing to moderate the injury outcome of a potential bicycle crash. Fences should have a fine meshed net construction to prevent bicycle handlebars from getting stuck. All road equipment should be designed without sharp edges as they could cause injuries to cyclists passing or crashing into the equipment.

Feasibility Study of Vietnam Fire and Disaster Prevention Agency Improvement Project through ODA Project I

By matching domestic ODA projects for specific implementation in accordance with the 2020 Fire and Disaster Prevention Agency Facility Infrastructure Master Plan and 2030 Vision, a social safety net construction project in Vietnam, its business feasibility was analyzed. Vietnam is undergoing rapid change and urbanization. As a result, demand in the firefighting sector is expected to increase rapidly. Because there are no domestic manufacturers of firefighting vehicles in Vietnam, the demand is largely satisfied through imports; however, the firefighting vehicles and additional devices provided through this ODA project should greatly contribute to the promotion of domestic exports. To represent the environmental factors that can cause fires in 58 provinces, the selection of project areas to support firefighting vehicles is based on population, jurisdictional area, population density, age of firefighting vehicles, number of firefighting targets, and number of firefighting vehicles in the past four years; the trend of reinforcement of firefighting vehicles and regional characteristics is determined. Twelve provinces in Vietnam were selected in the same way as the selected areas to support firefighting vehicles. This ODA project is expected to provide an opportunity to improve the legal and institutional aspects of the firefighting and disaster prevention field in Vietnam by applying domestic advanced firefighting force deployment standards.

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.

Leveraging machine learning to understand urban change with net construction

A key indicator of urban change is construction, demolition, and renovation. Although these development activities are often interrelated, they are typically studied independent of one another. Analytic methods relying on a strict set of modeling assumptions limit our ability to understand this change holistically. Machine learning has demonstrated the potential when combined with big data to discover patterns and relationships between seemingly unrelated variables. This research explores urban change through net construction, a composite value that treats demolition as a deductive process that is subtracted from construction activity which provides for a more holistic and nuanced understanding of development activity. Once validated through a visual analysis of its reliability as a measure of urban change, we then used a series of random forest regression models to evaluate the predictive accuracy of net construction compared with independent models of construction and demolition. Applying the approaches to an urban county in the United States, we compiled 122 independent variables to provide a comprehensive view of individual neighborhoods from multi-disciplinary data sources such as socioeconomic, built environment characteristics, and landscape metrics. We then analyze the feature importance scores derived from the random forest models in an effort to assess the similarities and differences between the variables that have the greatest influence on model accuracy. The net construction model produced more accurate results than models that used construction and demolition activity independently. While many of the most important features aligned with those from the independent models, land use mix drawn from landscape metrics appeared as the most important, representing a departure from previous studies. This study provides a scalable method for modeling urban change using machine learning techniques and reveals the importance of applying data-driven algorithms that can help communities become more informed about their pressing issues.

State-space Construction of Hybrid Petri Nets with Multiple Stochastic Firings

Hybrid Petri nets have been extended to include general transitions that fire after a randomly distributed amount of time. With a single general one-shot transition the state space and evolution over time can be represented either as a Parametric Location Tree or as a Stochastic Time Diagram . Recent work has shown that both representations can be combined and then allow multiple stochastic firings. This work presents an algorithm for building the Parametric Location Tree with multiple general transition firings and shows how its transient probability distribution can be computed using multi-dimensional integration. We discuss the (dis-)advantages of an interval arithmetic and a geometric approach to compute the areas of integration. Furthermore, we provide details on how to perform a Monte Carlo integration either directly on these intervals or convex polytopes, or after transformation to standard simplices. A case study on a battery-backup system shows the feasibility of the approach and discusses the performance of the different integration approaches.

Analysis of Construction Cost and Installation Ratio through Comparison of Fire-fighting Facility Design and Completion Documents for mid- and low-rise Buildings

The initial fire-fighting facility design plan may need to be changed during the construction of fire-fighting facilities because of alterations in the architectural design or the flexibility of the site situation. The difference between the 'design drawings at the stage of consenting for building approval' (Original design drawings) and the 'design drawings at the stage of consenting for use approval' (Completion drawings) ultimately leads to changes in the construction cost and in the performance of the fire-fighting facility. Therefore, to secure the fire safety of buildings and prevent human casualties, relevant case analyses and consequent institutional and systematic supplementation are necessary. In this study, six recently completed buildings were selected as target sites, the application rate of each fire-fighting facility in the initial design was analysed, and the need for institutional supplementation was suggested. As a result, owing to the design change, the construction cost and net construction cost could be reduced by up to 19% compared to those based on the original design. In particular, In particular, the sprinkler facility was found to match only 78.7% of the original design drawing in the completion drawing, showing the largest rate of design change among fire-fighting facilities.

Trammel net design engineering for operation with the sweeping method (Ciker net)

The active operation of a trammel net by a sweeping technique is commonly used by fishermen in Cilacap, which are often referred as ciker nets. They are operated by lowering the net in a straight line and pulling the tail end from a ship moving in a full circle, while the other end functions as a circular axis. The effect of active operation allows for changes in performance with time, such as easy lifting or less buoyancy, and the unstable display of gears. This makes it necessary to perform design engineering, especially on buoys, sinkers, and high nets. However, the suitable quantity of these components for ciker net has never been ascertained. Calculations about how many buoys, sinkers, and net height to add need to be done to enhance ciker net construction for active operation. This research aimed to determine the optimum configuration of buoys, sinkers, and net height, and determine the engineering design of ciker nets based on the optimum ratio of buoyancy force to the sinking force of the trammel net. Therefore, the parameters measured include hanging ratio, stretched net length, buoyancy force, and sinking force. The results showed that the optimum configuration of buoys, sinkers, and net height was 59 pieces, 341 pieces, and 1.5 m respectively. Changes in the design of ciker nets, especially in the three components that affect the addition of buoyancy and sinking force ratio were based on the comparison of the trammel nets which was 1:5 greater than the design owned by fishermen at 1:4.Keywords:Bouyancy forceSinking forceCiker netTrammel netShrimp

Design Characteristics and Specifications of Gill Net Operated Along the Lower Stretches of Vembanad Wetlands, Kerala, India

Gill net (Locally called odakku vala) design variation, operational techniques, catch composition and selectivity analysis in Vembanad wetland, Kerala was examined between January 2020 to June 2021. Netting materials used for gill net construction in Vembanad Lake were monofilament, multifilament Nylon (polyamide). The Gill net length was 25-55 m with a hung depth of 2-3 m. Gill net was highly species specific and showed selectivity for shallow water species. Its durability ranged from 3.5 months to 2 years depending on the netting material and the environmental conditions where it is being operated. Gill net fishery is one of the main types of artisanal fishery practiced occupationally by the fishermen community of Kerala. The region so far is untouched with the introduction of mechanized fishing apart from small traditionalized improvements. The Gill net was used to catch the fishes of marketable size, small fingerlings which were either used as bait or dried. Instead of using lead or aluminium needles as sinkers many of them were used to carry normal electric wire without copper string inside which reduce their cost of purchase.

On Weak $$\epsilon $$-Nets and the Radon Number

We show that the Radon number characterizes the existence of weak nets in separable convexity spaces (an abstraction of the Euclidean notion of convexity). The construction of weak nets when the Radon number is finite is based on Helly’s property and on metric properties of VC classes. The lower bound on the size of weak nets when the Radon number is large relies on the chromatic number of the Kneser graph. As an application, we prove an amplification result for weak \(\epsilon \)-nets.

A different approach to the network method: continuity equation in flow through porous media under retaining structures

PurposeThis study aims to present a new numerical model for the simulation of water flow through porous media of anisotropic character, based on the network simulation method and with the use of the free code Ngspice.Design/methodology/approachFor its design, it starts directly from the flow conservation equation, which presents several advantages in relation to the numerical simulation of the governing equation in terms of the potential head. The model provides very precise solutions of streamlines and potential patterns in all cases, with relatively small meshes and acceptable calculation times, both essential characteristics when developing a computational tool for engineering purposes. The model has been successfully verified with analytical results for non-penetrating dams in isotropic media.FindingsApplications of the model are presented for the construction of the flow nets, calculation of uplift pressures, infiltrated flow and average exit gradient in anisotropic scenarios with penetrating dams with and without sheet piles, being all this output information part of the decision process in ground engineering problems involving these retaining structures.Originality/valueThis study presents, for the first time, a numerical network model for seepage problems that is not obtained from the Laplace's governing equation, but from the water flow conservation continuity equation.