Cloud Picture Research Articles

Study of airborne LiDAR error based on flight simulation in atmospheric disturbance

Abstract The airborne LiDAR uses the aircraft as the observation platform, requiring the aircraft to keep a uniform speed and a straight-line cruise state, to obtain more accurate ranging information and a uniform laser foot point distribution cloud picture. Atmospheric turbulence is the main atmospheric disturbance that affects the aircraft movement in the cruise state, which can lead to a serious decrease in radar ranging accuracy and the distortion of cloud point distribution. In this paper, the motion error caused by atmospheric turbulence during flight is studied. The real-time simulation method based on the six degrees of freedom flight mechanics equation is used to establish the motion law of the carrier under atmospheric turbulence. The method’s reliability is verified by comparing it with flight test data. Then, the foot point distribution cloud image and ranging error of airborne LiDAR under different wind field intensities are simulated by real-time simulation of six degrees of freedom. The error law of radar motion affected by atmospheric turbulence is obtained.

Comprehensive Evaluation of Crack Safety of Hydraulic Concrete Based on Improved Combination Weighted-Extension Cloud Theory

When multiple elements come together, hydraulic concrete develops cracks of varying widths, which huts the dependability of buildings. Therefore, with pertinent tools or procedures, swiftly ascertaining the safety status of hydraulic concrete cracks under diverse service conditions is required by conducting a quantitative and qualitative analysis of the elements influencing the onset of cracks. This paper took the safety status of hydraulic concrete cracks as the main body of research; every step of hydraulic conservation infrastructure from the ground up—design stage, construction process, operation environment, and impoundment operation—was thoroughly examined. After establishing a multi-dimensional and multi-level system for the safety status evaluation of hydraulic concrete cracks, the subjective exponential AHP and objective CRITIC method were employed to determine the weight of each factor. Then, the two weights were processed using an enhanced combination assignment method to produce a more scientifically developed combination weight. Furthermore, fuzziness and randomness were considered in the quantitative analysis thanks to integrating cloud theory and extension matter elements. In order to determine the safety evaluation findings for hydraulic concrete fractures, the maximum membership principle and the cloud picture were employed. The conclusion reached after using this method to evaluate Dianzhan Dam was that the crack had a safety grade of III, meaning that it greatly impacted the reliability of the dam, and called for prompt acceptance or repair measures to improve building efficiency and safety.

Ultra-short-term forecast of distributed photovoltaic power based on satellite cloud image and LSTM model

Photovoltaic (PV) power generation, with its volatile, intermittent, and random characteristics, and large-scale PV access pose a threat to grid stability. For this reason, predicting the photovoltaic output will help keep the grid safe and stable. On the basis of the influence of cloud groups on solar radiation, a very short-term forecast of distributed PV energy will be made using satellite cloud picture information to improve the forecast accuracy of PV energy production. The paper presents a method to predict distributed PV power at very short notice based on satellite clouds and a network model with Long Short-Term Memory (LSTM). First, extract a subset of meteorological and PV power data from the forecast area as training samples., and the abnormal part of the samples is cleaned by an isolated forest algorithm. Secondly, the occlusion feature is extracted from the satellite cloud image in the same period. Finally, the measured solar irradiance, meteorological information, and obscuration features are input into the LSTM network for prediction, and the photovoltaic power prediction results in the next 4 hours are obtained. The measured PV power of Jinghai Guangfu Power Station in Hefei, Anhui province on the 5th day was the training sample for the prediction of PV power on the 6th day. The prediction results show that the prediction error is 2.73% when a satellite cloud image is added, and 16.15% when a satellite cloud image is not added, and the prediction error is reduced by 13.42%.

A method for sizing air source heat pump considering the joint effect of outdoor air temperature and relative humidity

When operated in a highly humid environment, frost may accumulate on the surface of the outdoor coil in air source heat pump units (ASHPs), leading to a reduction in its output heating capacity. Currently, the existing methods for sizing ASHPs only considered the effect of outdoor air temperature, Ta, without taking into account the effect of relative humidity, RH, on output heating capacity. This often resulted in an insufficient heating capacity from an ASHP selected. To resolve this issue, a model for predicting the output heating capacity of ASHPs, Qh, was established firstly. Then, considering the variation in the rated output heating capacity of ASHPs, a method for sizing ASHPs considering the joint effect of Ta and RH has been developed. Besides, for practical application, a capacity design correction factor, K, was proposed, evaluated, and plotted as a cloud picture. Evaluating results indicated that K can be used for sizing ASHPs accurately. When the effect of frosting on Qh was considered, the maximum rates of decrease in the output heating capacity correction factor, KQ, was between 43.8% and 50.0%, and the outdoor air design temperatures for space heating in six typical Chinese cities were decreased by 1.8–3.5 °C, with the average of 2.8 °C. For highly humid cities, such as Qiannan area China, even if its outdoor air design temperature was 1.4 °C higher than that in Chongqing City, the K value was 0.24 lower.

Numerical Simulation on Borehole Instability Based on Disturbance State Concept

This paper carries out a study on the numerical simulation of borehole instability based on the disturbance state concept. By introducing the disturbance damage factor into the classical Mohr–Coulomb yield criterio, we establish a finite element hydro-mechanical coupling model of borehole instability and program the relevant field variable by considering elastic–plastic deformation in borehole instability, the distribution of the damage disturbance area, the variation of porosity and permeability with the disturbance damage factor, etc. Numerical simulation shows that the borehole stability is related to the action time of drilling fluid on the wellbore, stress anisotropy, the internal friction angle of rock, and borehole pressure. A higher horizontal stress difference helps suppress shear instability, and a higher rock internal friction angle enhances shear failure around the borehole along the maximum horizontal principal stress. When considering the effect of the internal friction angle of rock, the rock permeability, disturbance damage factor, and equivalent plastic strain show fluctuation characteristics. Under the high internal friction angle of rock, a strong equivalent plastic strain area and disturbance damage area occur in the direction of the maximum horizontal principal stress. Their cloud picture shows the mantis shape, where the bifurcation corresponds to the whiskers of the shear failure area in borehole instability. This study provides a theoretical basis for solving the problem of borehole instability during drilling engineering.

Product design evaluation based on FAHP and cloud model

In view of the shortcomings of the existing evaluation methods in fully considering the fuzziness and randomness of product design evaluation, a novel product design evaluation method based on FAHP and cloud model is proposed. First, a hierarchical structure model of product design evaluation is established. Second, fuzzy pairwise comparison of criteria is constructed through questionnaire survey, and the digital characteristics of weight cloud model are acquired by the proposed fuzzy weight model. Then, based on the factor scores, the digital characteristics of scoring cloud model are obtained by backward cloud. Finally, the digital characteristics of comprehensive evaluation cloud model are obtained by using the proposed improved fuzzy composite operator, and the forward cloud is used to get the cloud picture for evaluation. Taking reading lamp as an example, the feasibility and effectiveness of the proposed method are verified. The results show that compared with the other two methods, the Kendall rank correlation coefficients of entropy of the method are increased by 0.17 and 0.33, respectively, which proves that the method achieves more accurate evaluation result under the complex criteria, and provides a more effective tool for decision makers and designers to evaluate and optimize design schemes.

Assessment of effect on water quality by hybrid constructed floating treatment wetlands in the low flow urban rivers.

In this study, the effect of hybrid constructed floating treatment wetlands (FTWs) in a low-flow urban river was evaluated, and the influence radius on dissolved oxygen (DO), ammonia nitrogen (NH4+-N), and total phosphorus (TP) under different flow conditions was quantified. It was found that DO considerably increased and NH4+-N and TP decreased at the outlet after treatment with hybrid constructed FTW. The NH4+-N removal rate continued to increase to 72.03%, whereas that for TP decreased to 63.16% with fluctuation. The cloud picture of the influence radius showed that when DO ≤ 3 mg/L, Rflow ≈ 5 m, Rstill ≈ 3 m, and when DO > 3 mg/L, Rflow = Rstill ≈ 8 m. For NH4+-N under flow conditions, Rflow ≈ 8 m, whereas under still conditions when NH4+-N ≤ 7 mg/L, Rstill ≈ 5 m, and when NH4+-N > 7 mg/L, the concentration changes were not considerable. When TP ≤ 0.4 mg/L, Rflow ≈ 5 m, and when TP > 0.4 mg/L, Rflow ≈ 8 m; while under still conditions, when TP ≤ 0.8 mg/L, Rstill ≈ 5 m, and when TP > 0.8 mg/L, the concentration changes were not remarkable. Various water quality parameters and water flow affected the radius of influence of FTW on DO, NH4+-N, and TP at the spatial level. For the same water quality parameter, the influence radius in the flow state was larger than that in the still state (Rflow ≥ RStill). This study evaluated treatment efficiency of the hybrid constructed FTW in urban rivers and provided guidance and support for FTW deployment in future.

Research on recognition of ice and snow athletes based on feature extraction and cloud computing platform

A common method for the treatment of sports injuries for a long time to provide localized cooling in ice or snow is fomentation. This system will support a feature extraction cloud computing platform application of localized cooling which is applied to the shape of ice snow for treatment of sports injuries. It is a common method of treatment of sports injuries. Athletes usually utilizes the application of therapeutic hypothermia to return to athletic activities.. Two review authors have independently assessed the relevance and impact calculations involved in the trial, and the cloud worker permits the highlights removed legitimately from the scrambled picture. Awareness of disability sport, in particular para snowboard, may not be common or easily available, so it is important that these potential athletes know that the sport exists and where they can try the sport for the first time Some examination and test results show that, for protection trademark picture extraction, proposed technique is successful, safe, and it might be applied to the cloud picture secure figuring applications.

Macro-micro interaction mechanism between FRPC pile and sand under horizontal bidirectional load

FRPC pile is a new type of composite pile formed by combining FRP material with traditional material. It has good physical and chemical erosion resistance, light weight, high strength and other advantages. Based on the particle image velocity measurement (PIV) technique, this paper studies the interaction between sand soil and FRPC pile by applying bidirectional horizontal load on the FRPC model pile embedded in sand soil. In the process of loading the FRPC model pile, a CCD high-speed industrial camera is used to take gray image of sand deformation around the test observation surface pile. DH3816 Strain Collecting Instrument was used to collect pile side strain, and image processing software PIVview2C was used to get displacement cloud picture. By analyzing the distribution of total displacement, horizontal displacement and vertical displacement of sandy soil under different loads, the micro mechanism of FRPC pile and sandy soil is clarified. The distribution of pile side moment was studied, and the macro mechanism of FRPC pile and sandy soil is clarified.

Discrete Element Simulation Study on Particle Segregation Effect of a Hemispherical Shell Swing-Oscillating Trough Under Combination Swing-Oscillating

In order to enhance the segregation effect of material particles in a hemispherical shell swing-oscillating trough under combination swing-oscillating, by means of three dimensional discrete element method, and by use of the two-dimensional dry granules of plastic ball and steel ball, the discrete element simulation study of particle segregation process is carried out in turn in three cases, which is composed of a single swing-oscillating in smooth trough, a combination swing-oscillating in smooth trough, and a combination swing-oscillating in adding bulge trough. The particle segregation effect was evaluated by particle volume concentration and combined with segregation cloud picture simulated. The result indicates that segregation effect of combination swing-oscillating is better than that in single swing-oscillating; layering effect of the trough added bulge is better than that in the smooth trough. And compared to single swing-oscillating in smooth trough, the degree of segregation of particles in added bulge trough can be increased by 10–15% when being combination swing-oscillating.

The cloud retrieval of combining sparse representation with subspace projection

Satellite cloud imagery can show the features and the evolution processes of all kinds of cloud systems from different aspects. Thus, adopting the content-based cloud image retrieval makes a big difference in supervising present weather conditions and studying the climate change. In order to optimize the combined features of the cloud picture and strengthen the generalization ability of its combined features, this paper presents an optimal method of combining the features of the sparse representation with the subspace projection. At first, we should extract its color, texture and shape, convert all the combined features, and divide them into different blocks. Then, we can make the sparse representation for each block's features, grouping them according to different atom variance and gaining both noticeable and unnoticeable features. Finally, we can count the power of the grouped features to get the subspace projection matrix, projecting the original combined features on it and achieving the optimal cloud picture features. The experiment turns out that the method of optimizing the cloud picture features in this paper is better than common descending dimension method and cloud retrieval technology in precision ratio and recall ratio. It indeed has a stronger optimization in the combined features as well as a lower time complexity in the process of the real-time retrieval, which indicates a brand new retrieval method.

Perspectives of Threat Modeling of a Secure Cloud Picture Archiving and Communication System

Perspectives of Threat Modeling of a Secure Cloud Picture Archiving and Communication System

Perspectives of Threat Modeling of a Secure Cloud Picture Archiving and Communication System

The Picture Archiving and Communication System (PACS) used in electronic health, is computationally enhanced by the migration into the cloud, which reduces the cost of storage space and equipment. However, cloud-PACS technology is susceptible to threats and vulnerabilities. This paper implements a threat modeling approach on a cloud-PACS framework, using Microsoft Threat Modelling Tools. Security requirements and mitigation strategies were formulated for the implementation of the framework, in order to improve cloud PACS security.

Stiffness analysis of a metamorphic parallel mechanism with three configurations

Compared with series mechanisms, a parallel mechanism has the merits of high stiffness, fast response, and centralised layout of electric cylinders, which is more suitable for the mechanical leg of a rescue robot. However, it is not flexible enough to improve the environment adaptability of the robot. Adding the abilities of reconfiguration and mobility change to general parallel mechanisms, a novel metamorphic parallel mechanism for robotic legs is proposed based on an innovative rotatable-axis revolute joint. The inverse kinematic model of the new mechanism is established and the constraint conditions and ranges of the key parameters are explored, as well as obtaining the cloud picture of its workspace. The stiffness model is formulated with the consideration of the deformation of the main components caused by the actuation and constraints, utilising the screw theory. The stiffness matrices of the home positions of configurations I and III are then acquired and the stiffness distributions in the sub-workspace around the desired trajectory are evaluated, which are expected to lay a good theoretical foundation for the application of this novel mechanism.

Research on influence of spinning process parameters based on simulation and experiment

In this paper, we focus on the need for the process of spinning manufacturing, the spinning manufacturing simulation of INCONEL718 cylinder part was finished, the scheme consists of two-pass and three wheels spinning, three wheels offset. The FEM (finite element analysis) was used to finish the spinning manufacturing simulation, the stress-strain cloud picture was attained, it takes the wall thickness difference as analysis object, the influence law of spinning wheel feed rate and spinning wheel working angle was analyzed, the spinning manufacturing experiment was done based on the parameters attained by simulation, experimental result coincides with the simulation result. The experimental result shows that the simulation methods and parameters are beneficial to the actual spinning manufacturing.

Numerical simulation of temperature field and stress field in fused deposition modeling

Fused deposition modeling (FDM) is a rapid prototyping technology developed quickly in recent years. However, the precision of forming part is a key factor to limit the development of fused deposition modeling. This paper established numerical model of temperature filed and stress filed for the forming process of fused deposition modeling by finite element modeling method and “birth-death element” technique. From the analysis of temperature gradient cloud picture, the result indicates that the temperature distributions are uneven along both X and Y directions, but the temperature distribution is uniform along Z direction. From the analysis of stress field for forming parts, the result can be found that deformation is focused on the plane XOY and no obvious stress concentration is observed on the plane XOZ and YOZ. Based on the comparison of temperature fields for four different scanning filling paths (honeycomb, grid, wiggle, rectilinear), the results show that the smallest temperature gradient is found for honeycomb scanning filling path. Based on the comparison of stress fields for four different scanning filling paths, the results show that the most uniform stress distribution and the smallest deformation is honeycomb scanning filling path which can provide guiding significance for actual processing.

The buckling behavior of radome with different braided angles based on CFRP

Radomes with traditional splicing structure has non-entirety failures of joins and rivets, so it cannot give full play to the structure’s carrying efficiency after shocking. A new kind of radome is put forward, an improved version of the traditional splicing structure, with Carbon Fiber Reinforced Polymer (CFRP) structure. We combined theoretical analysis, finite element simulation and experimental test as well as compared and analyzed compressed cloud picture of displacement and stress distribution of radomes with two braided angles structures (90° and 60°) in order to study the deformation and stress capacity of radome after stressing. Simulation result: the compressed displacement of two kinds of radomes increaseslinearly, compressed stress diagram increases in a jagged way liking a parabola. Under the same compressed displacement, braided angle of 90° enjoys bigger compressed stress than that of 60°; under the same load, braided angle of 90° enjoys smaller compressed displacement than that of 60° with less joints cracking. The experiment shows that some of the joints cracked because the connection between braiding joints coupled. But the stressing deformation and stress development of radome match the simulation results basically.

Finite Element Modeling and Simulating of Physical Process of Impacting by Tidal Current

Take the new tidal current energy utilizing device as study object, finite element modeling and simulating of physical process of impacting by tidal current are studied. Further, the physical process of impacting by the tidal current is analyzed, and the contour map of force, cloud picture of pressure distribution, vector diagram of water flow velocity and route map of water flow for the rotating blade are obtained. Our studies have shown that the force in front of blade is uneven, and the force of one end near pillar is bigger, but the force in reverse side is even, as the same time, the flow becomes divergence after impacting blade, flowing to the edge of blade.

Research on the cathode design and experiments of electrochemical machining a closed impeller internal flow channel

In order to improve the electrochemical machining (ECM) precision and efficiency of a closed impeller internal flow channel, the internal flow channel cathode shape and structure were optimized by gap flow field simulation. Firstly, the theoretical model and three-dimensional gap flow field simulation geometric model were set up. Next, the inter-electrode gap flow field simulation results were draw from the streamline, velocity, and pressure cloud picture. Secondly, the cathode and the frock clamp were designed according to the simulation results. Finally, the verification experiment was carried out to evaluate the cathode structure and the ECM process parameters, and the experimental results were consistent with the simulation results. The whole process is stable and no short-circuit phenomenon with the forward flow field machining pattern. The results show that the method of gap flow field simulation-assisted ECM cathode design is useful and economical for machining closed impeller internal flow channel.

Electrochemical machining flow field simulation and experimental verification for irregular vortex paths of a closed integer impeller

Electrochemical machining (ECM) is an economical and effective method for machining hard-to-cut metal materials into complex shapes in aerospace and aeronautics fields, which are difficult to machine with conventional methods. As we all know, electrolyte flow field is one of the important factors in ECM irregular vortex paths of the closed integer impeller. To improve the stability of the whole processing, the flow field mathematical model was developed. The 3-D gap flow field simulation models of the reversed flow and forward flow patterns were also established, respectively. From the streamline, velocity, and pressure cloud picture of the electrolyte flow field simulation, the results showed that under the reversed pattern, the electrolyte flow velocity in the front gap and the side gap was not only higher but also more uniform than the forward pattern. Finally, the experimental verification was carried out and the experimental results were consistent with the simulation results. The whole process is stable and has no spark and no short circuit phenomenon with the reverse flow pattern. We successfully obtained 0.8-micron surface roughness of the machined workpiece. On the contrary, the irregular vortex paths cannot be successfully processed by forward flow pattern. The results indicate that reverse flow pattern is an effective and feasible method to machining irregular vortex paths of the closed integer impeller.