Automated Dimensioning Method of Engineering Drawings for Mechanical Products Based on Curve Chain

An automated method based on the curve chain was proposed for dimensioning of engineering drawings for the mechanical products.According to the internal relation between the features of 3D model feature and elements of 2D drawing,the curve chain was established to reflect the geometric topological structure between the elements.It divides the dimensions into the absolute dimensions within the cure chain and the relative dimensions between the curve chains.The parallel and lengthy relationship between the drawing elements of the constructed X and Y parallel matrix was solved to remove redundant elements in the curve chain and labeled the absolute dimensions of the remaining valid elements.The average minimum weight coefficient was introduced to judge the dependence on the relative dimensions between curve chains.Through the analysis of the overlap between the circular rectangular areas,including all the absolute dimensions of the curve chains,overlapping curve chains were merged,and their dimensions were rearranged to avoid the cross interference between them.The method was seamlessly integrated into the drafting module of product design software NX,and it developed an automated dimensioning system.The examples show that the system has excellent interactivity and robustness in the dimensioning of product engineering drawings.The dimension information is complete,accurate and reliable.

Improved Radio Network Dimensioning for Real-Time Polling Service on IEEE 802.16 Wireless Networks with QoS Consideration

Recently, applications of real-time polling service (rtPS) in IEEE 802.16 wireless networks have gained considerable popularity. These applications generate large amounts of real time traffic in the network and thus maintaining the quality of service (QoS) such as packet delay requirement in rtPS dominant networks is critical. Existing dimensioning methodology does not consider QoS parameters of rtPS in network dimensioning. Moreover, exhaustive and time-consuming simulations are required to evaluate the performance and QoS of rtPS. To overcome this problem, we propose an improved radio network dimensioning framework which considers QoS parameters of rtPS in network dimensioning. In this framework, an analytical model is developed to evaluate the capacity and performance of rtPS in IEEE 802.16 wireless networks. The proposed framework provides a fast and accurate means of finding the trade-off between system load and packet delay, thus providing network operators with an analytical tool that jointly considers coverage, capacity and QoS requirements for obtaining the minimum number of sites required. The accuracy of the proposed model is validated through simulations.

Improved Multiple-Scenario Radio Network Dimensioning for WCDMA

In wideband code division multiple access (WCDMA) cellular systems, the coverage radius of a cell depends on its current capacity level. As a result, existing WCDMA radio network dimensioning approaches require that coverage and capacity planning be carried out jointly in an iterative manner in order to obtain the minimum site count needed while fulfilling both coverage and capacity requirements. This requires relatively long computational time, particularly when there are many scenarios or what-if cases to be considered. To overcome this problem, we propose an alternative radio network dimensioning approach where coverage planning and capacity planning can be carried out separately to reduce computational time. Besides, a portion of the values calculated in the initial iteration is preserved in a lookup graph, allowing future what-if analysis to be accomplished rapidly. Simulation results show that, unlike the existing approach, the planning and what-if analysis times of the proposed dimensioning approach are independent of the number of sce-narios considered. Lastly, we present a few case studies and show that the proposed dimensioning method can give the same prediction accuracy as the existing method.

Wavelength dimensioning for wavelength-routed WDM satellite network

Internet and broadband applications driven by data traffic demand have become key dri- vers for satellite constellations. The key technology to satisfy the high capacity requirements between satellites is optical satellite networks by means of wavelength division multiplexing inter- satellite links （ISLs） with wavelength routing （WDM-OSN）. Due to the limited optical amplifier bandwidth onboard the satellite, it is important to minimize the wavelength requirements to provi- sion requests. However, ISLs should be dynamically established and deleted for each satellite according to its visible satellites. Furthermore, different link assignments will result in different topologies, hence yielding different routings and wavelength assignments. Thus, a perfect match model-based link assignment scheme （LAS-PMM） is proposed to design an appropriate topology such that shorter path could be routed and less wavelengths could be assigned for each ISL along the path. Finally, simulation results show that in comparison to the regular Manhattan street net- work （MSN） topology, wavelength requirements and average end-to-end delay based on the topol- ogy generated by LAS-PMM could be reduced by 24.8% and 12.4%, respectively.

Fractal Study on the Evolution of Micro-Pores in Concrete Under Freeze-Thaw

After exposure to freeze-thaw cycles, scanning electron microscopy(SEM) and nuclear magnetic resonance(NMR) were used to test the four mixtures. The microstructure is qualitatively analyzed from the 2D SEM image and the 3D pore distribution curve before and after freezing and thawing. The fractal dimension is utilized to characterize the two-dimensional topography image and the three-dimensional pore distribution, quantitatively. The results reveal that the surface porosity and volume porosity increase as the freeze-thaw action increases. Self-similarity characteristics exist in micro-damage inside the concrete. In the fractal dimension, it is possible to characterize pore evolution quantitatively. The fractal dimension correlates with pore damage evolution. The fractal dimension effectively quantitatively characterizes micro-damage features at various scales from the local to the global level.

Multi-surrogate framework with an adaptive selection mechanism for production optimization

Data-driven surrogate models that assist with efficient evolutionary algorithms to find the optimal development scheme have been widely used to solve reservoir production optimization problems.However,existing research suggests that the effectiveness of a surrogate model can vary depending on the complexity of the design problem.A surrogate model that has demonstrated success in one scenario may not perform as well in others.In the absence of prior knowledge,finding a promising surrogate model that performs well for an unknown reservoir is challenging.Moreover,the optimization process often relies on a single evolutionary algorithm,which can yield varying results across different cases.To address these limitations,this paper introduces a novel approach called the multi-surrogate framework with an adaptive selection mechanism(MSFASM)to tackle production optimization problems.MSFASM consists of two stages.In the first stage,a reduced-dimensional broad learning system(BLS)is used to adaptively select the evolutionary algorithm with the best performance during the current optimization period.In the second stage,the multi-objective algorithm,non-dominated sorting genetic algorithm II(NSGA-II),is used as an optimizer to find a set of Pareto solutions with good performance on multiple surrogate models.A novel optimal point criterion is utilized in this stage to select the Pareto solutions,thereby obtaining the desired development schemes without increasing the computational load of the numerical simulator.The two stages are combined using sequential transfer learning.From the two most important perspectives of an evolutionary algorithm and a surrogate model,the proposed method improves adaptability to optimization problems of various reservoir types.To verify the effectiveness of the proposed method,four 100-dimensional benchmark functions and two reservoir models are tested,and the results are compared with those obtained by six other surrogate-model-based methods.The results demonstrate that our approach can obtain the maximum net present value(NPV)of the target production optimization problems.

Dimension by Dimension Finite Volume HWENO Method for Hyperbolic Conservation Laws

In this paper,we propose a finite volume Hermite weighted essentially non-oscillatory(HWENO)method based on the dimension by dimension framework to solve hyperbolic conservation laws.It can maintain the high accuracy in the smooth region and obtain the high resolution solution when the discontinuity appears,and it is compact which will be good for giving the numerical boundary conditions.Furthermore,it avoids complicated least square procedure when we implement the genuine two dimensional(2D)finite volume HWENO reconstruction,and it can be regarded as a generalization of the one dimensional(1D)HWENO method.Extensive numerical tests are performed to verify the high resolution and high accuracy of the scheme.

Prediction of collapse process and tipping points for mutualistic and competitive networks with k-core method

Ecosystems generally have the self-adapting ability to resist various external pressures or disturbances,which is always called resilience.However,once the external disturbances exceed the tipping points of the system resilience,the consequences would be catastrophic,and eventually lead the ecosystem to complete collapse.We capture the collapse process of ecosystems represented by plant-pollinator networks with the k-core nested structural method,and find that a sufficiently weak interaction strength or a sufficiently large competition weight can cause the structure of the ecosystem to collapse from its smallest k-core towards its largest k-core.Then we give the tipping points of structure and dynamic collapse of the entire system from the one-dimensional dynamic function of the ecosystem.Our work provides an intuitive and precise description of the dynamic process of ecosystem collapse under multiple interactions,and provides theoretical insights into further avoiding the occurrence of ecosystem collapse.

Triaxial mechanical properties and precursors of instability damage in rocks with different laminar dip angles

To investigate the mechanical failure characteristics of volcanic breccia with different bedding dip angles in deep layers,triaxial compression experiments were conducted on specimens taken from volcanic rock layers in the Junggar Basin,Xinjiang.By changing the confining pressure,we compared the mechanical properties,acoustic emission characteristics,and fractal features of the acoustic emission sequence for volcanic breccia with different bedding dip angles.The research results indicate that as the bedding dip angle increases,peak strength,internal friction angle,and cohesion exhibit a“U-shaped”variation pattern.The correlation dimension of the acoustic emission amplitude was calculated using the G-P algorithm,revealing that volcanic breccia exhibits fractal characteristics.Furthermore,a positive correlation between the correlation dimension and the bedding dip angle was observed.When the stress of the test specimen reaches 0.8σ_(c),there is a significant decrease in the fractal dimension,serving as a criterion for predicting the failure of the specimen.By analyzing the changes in fractal dimension at different stress levels,the slope of the fractal dimension△D<-0.5 can be used as a precursor to failure for test specimens with a bedding dip angle of 15°≤β≤45°.Similarly,when the bedding dip angle of the specimen is 0°≤β<15°or 45°<β≤90°,△D<0 can be considered as a precursor to specimen failure.This study provides theoretical references for understanding the failure patterns of volcanic rock.

Damage Characteristics Analysis and Fractal Study of Shale With Prefabricated Fractures under Thermal-mechanical Coupling

To study the damage and failure of shale with different fracture inclination angles under uniaxial compression loading,in this work,RFPA2D-Thermal,a two-dimensional real failure process analysis software,was used for numerical simulation.Numerical simulation results show that quartz in shale mainly affects the tensile and compressive strength of shale by increasing rock brittleness.The coupling of temperature and pressure will cause lateral and volume destruction of shale,which enables the shale body to be more easily broken.Fracture inclination is the key factor affecting shale damage patterns.The failure mode of shale with low-and high-angle fractures is mainly shear failure,and the compressive strength does not vary with crack inclination.The damage mode of obliquely intersecting fractured shale is slip damage along the fracture face,the compressive strength decreases and then increases with the fracture inclination,and a minimum value exists.The acoustic emission simulation results of the damage process effectively reflect the accumulated internal damage and macroscopic crack appearance until fracture instability when the prefabricated fractured shale is subjected to uniaxial compressive loading.The crack inclinations of 0°and 120℃ corresponds to the most complex"N"shape damage mode.The crack inclinations of 30°and 60°,and the damage mode is an inverted"λ"shape.

Microstructure Characterization of Bubbles in Gassy Soil Based on the Fractal Theory

The microscopic characterization of isolated bubbles in gassy soil plays an important role in the macroscopic physical properties of sediments and is a key factor in the study of geological hazards in gas-bearing strata.Based on the box-counting method and the pore fractal features in porous media,a fractal model of bubble microstructure parameters in gassy soil under different gas con-tents and vertical load conditions is established by using an industrial X-ray CT scanning system.The results show that the fractal di-mension of bubbles in the sample is correlated with the volume fraction of bubbles,and it is also restricted by the vertical load.The three-dimensional fractal dimension of the sample is about 1 larger than the average two-dimensional fractal dimension of all the slices from the same sample.The uniform porous media fractal model is used to test the equivalent diameter,and the results show that the variation of the measured pore diameter ratio is jointly restricted by the volume fraction and the vertical load.In addition,the measured self-similarity interval of the bubble area distribution is tested by the porous media fractal capillary bundle model,and the fitting curve of measured pore area ratio in a small loading range is obtained in this paper.

Macro-micro behaviors and failure mechanism of frozen weakly cemented mudstone

Understanding the mechanical properties and multiscale failure mechanism of frozen soft rock is an important prerequisite for the construction safety of tunnels,artificially frozen ground and other infrastructure in cold regions.In this study,the triaxial compression test are performed on mudstone in the weakly cemented soft rock strata in the mining area of western China,and the mechanical characteristics and failure mechanism of weakly cemented mudstone are systematically investigated under the combined action of freezing and loading.Furthermore,the quantitative relationship between the microstructural parameters and the macroscopic strength and deformation parameters is established based on fractal theory.Thus,the failure mechanism of frozen weakly cemented mudstone is revealed on both micro- and macro-scales.The results show that temperature and confining pressure significantly affects the elastic modulus and peak strength of weakly cemented mudstone.With decreasing temperature,the compressive strength increases,while the corresponding peak strain decreases gradually.On the deformation curve,the plastic deformation stage is shortened,and the brittle fracture feature at the post-peak stage is more prominent,and the elastic modulus correspondingly increases with decreasing temperature.Under low-temperature conditions,most of the weakly cemented mudstone undergoes microscopic shear failure along the main fracture surface.The micro-fracture morphology characteristics of weakly cemented mudstone under different temperatures are quantified via the fractal dimension,and an approximately exponential relationship can be obtained among the fractal dimension and the temperature,compressive strength and elastic modulus.

Fractal analysis of major faults and fractal dimension of lineaments in the Indo-Gangetic Plain on a regional scale

The Indo-Gangetic Plain(IGP)is one of the most seismically vulnerable areas due to its proximity to the Himalayas.Geographic information system(GIS)-based seismic characterization of the IGP was performed based on the degree of deformation and fractal dimension.The zone between the Main Boundary Thrust(MBT)and the Main Central Thrust(MCT)in the Himalayan Mountain Range(HMR)experienced large variations in earthquake magnitude,which were identified by Number-Size(NS)fractal modeling.The central IGP zone experienced only moderate to low mainshock levels.Fractal analysis of earthquake epicenters reveals a large scattering of earthquake epicenters in the HMR and central IGP zones.Similarly,the fault fractal analysis identifies the HMR,central IGP,and south-western IGP zones as having more faults.Overall,the seismicity of the study region is strong in the central IGP,south-western IGP,and HMR zones,moderate in the western and southern IGP,and low in the northern,eastern,and south-eastern IGP zones.

An Exploration of the Three Dimensions and Epochal Strengths of Building a Human Community With a Shared Future

The idea of a human community with a shared future was proposed by the Communist Party of China(CPC)Central Committee with Comrade Xi Jinping at its core for the future development of human beings to face up to the most important question in today's world:“What is happening to the world and what should we do?”It profoundly answers the question of the world,history,and the times.The theory of a human community with a shared future is an innovative theory with a multidimensional formation logic that guides humanity toward continually seeking common interests and values.This paper dives into the profound motivations behind building a human community with a shared future from historical,cultural,and practical dimensions and analyzes its epochal value from both domestic and international perspectives.This not only helps exert China's role in the international community,contributing Chinese strength to the construction of a peaceful,stable,and prosperous human society,but also enhances the influence of the idea of a human community with a shared future in the international community,accelerating the building of a human community with a shared future that considers the legitimate concerns of all countries,and aiding in solving the crises facing the world.

Drawing Recognition for Automatic Dimensioning of Shear-Walls

In computer-aided structural design, the drawing of shear-walls cannot be easily automated; however, dimensioning of the shear-walls provides a method to automate the drawing. This paper presents a drawing recognition method for automatic dimensioning of shear-walls. The regional relationship method includes a graphic shape template library that can learn new shear-wall shapes. The automatic dimensioning of shear-walls is then realized by matching the templates. The regional relationship method for graph recognition effectively describes the topological relationships for graphs to significantly increase the recognition efficiency.

Considering functional dimensioning in architectural design

This paper presents an overview of the functional dimensioning （FD） concept apptied to the construction sector. FD addresses the issue of toterance; construction involves severat trades working together white each trade has its own construction toterances. To investigate this probtem, three case studies are investigated. The first one describes a classic case of a window in a bay and the way constructors sotved the resulting toterance problems. The second case study describes the notion of chain dimension. The fast case study presents the notion of wedge as a sotution to sotve probtems related to toterance gap accumulation. This paper is of interest to the scientific community that is working to industrialize the construction sector and atso to architects （in the design）, construction managers （onsfte）, and manufacturers （construction trades）.

The Global Attractor and Its Dimension Estimation of Generalized Kolmogorov-Petrovlkii-Piskunov Equation

In this paper, the initial boundary value problem of a class of nonlinear generalized Kolmogorov-Petrovlkii-Piskunov equations is studied. The existence and uniqueness of the solution and the bounded absorption set are proved by the prior estimation and the Galerkin finite element method, thus the existence of the global attractor is proved and the upper bound estimate of the global attractor is obtained.

Measurement Uncertainty Analysis of the Rotary-scan Method for the Measurable Dimension of Cylindrical Workpieces

The measurement uncertainty analysis is carried out to investigate the measurable dimensions of cylindrical workpieces by the rotary-scan method in this paper.Due to the difficult alignment of the workpiece with a diameter of less than 3 mm by the rotary scan method,the measurement uncertainty of the cylindrical workpiece with a diameter of 3 mm and length of 50 mm which is measured by a roundness measuring machine,is evaluated according to GUM(Guide to the Expression of Uncertainty in Measurement)as an example.Since the uncertainty caused by the eccentricity of the measured workpiece is different with the dimension changing,the measurement uncertainty of cylindrical workpieces with other dimensions can be evaluated the same as the diameter of 3 mm but with different eccentricity.Measurement uncertainty caused by different eccentricities concerning the dimension of the measured cylindrical workpiece is set to simulate the evaluations.Compared to the target value of the measurement uncertainty of 0.1μm,the measurable dimensions of the cylindrical workpiece can be obtained.Experiments and analysis are presented to quantitatively evaluate the reliability of the rotary-scan method for the roundness measurement of cylindrical workpieces.

A Dimensional Reduction Approach Based on Essential Constraints in Linear Programming

This paper presents a new dimension reduction strategy for medium and large-scale linear programming problems. The proposed method uses a subset of the original constraints and combines two algorithms: the weighted average and the cosine simplex algorithm. The first approach identifies binding constraints by using the weighted average of each constraint, whereas the second algorithm is based on the cosine similarity between the vector of the objective function and the constraints. These two approaches are complementary, and when used together, they locate the essential subset of initial constraints required for solving medium and large-scale linear programming problems. After reducing the dimension of the linear programming problem using the subset of the essential constraints, the solution method can be chosen from any suitable method for linear programming. The proposed approach was applied to a set of well-known benchmarks as well as more than 2000 random medium and large-scale linear programming problems. The results are promising, indicating that the new approach contributes to the reduction of both the size of the problems and the total number of iterations required. A tree-based classification model also confirmed the need for combining the two approaches. A detailed numerical example, the general numerical results, and the statistical analysis for the decision tree procedure are presented.

Computational Quantification of Map Projection Distortion by Fractal Dimension of Coastlines

Maps, essential tools for portraying the Earth’s surface, inherently introduce distortions to geographical features. While various quantification methods exist for assessing these distortions, they often fall short when evaluating actual geographic features. In our study, we took a novel approach by analyzing map projection distortion from a geometric perspective. We computed the fractal dimensions of different stretches of coastline before and after projection using the divide-and-conquer algorithm and image processing. Our findings revealed that map projections, even when preserving basic shapes, inevitably stretch and compress coastlines in diverse directions. This analysis method provides a more realistic and practical way to measure map-induced distortions, with significant implications for cartography, geographic information systems (GIS), and geomorphology. By bridging the gap between theoretical analysis and real-world features, this method greatly enhances accuracy and practicality when evaluating map projections.