Adaptive electricity theft detection method based on load shape dictionary of customers

With the application of the advanced measurement infrastructure in power grids,data driven electricity theft detection methods become the primary stream for pinpointing electricity thieves.However,owing to anomaly submergence,which shows that the usage patterns of electricity thieves may not always deviate from those of normal users,the performance of the existing usage-pattern-based method could be affected.In addition,the detection results of some unsupervised learning algorithm models are abnormal degrees rather than“0-1”to ascertain whether electricity theft has occurred.The detection with fixed threshold value may lead to deviation and would not be sufficiently flexible to handle the detection for different scenes and users.To address these issues,this study proposes a new electricity theft detection method based on load shape dictionary of users.A corresponding strategy for tunable threshold is proposed to optimize the detection effect of electricity theft,and the efficacy and applicability of the proposed adaptive electricity theft detection method were verified from numerical experiments.

Ultimate Load Capacity of Offshore Pipeline with Arbitrary Shape Corrosion Defects

A set of generalized solutions are proposed for estimating ultimate load capacity of pipeline with arbitrary corrosion shapes subjected to combined internal pressure, axial force and bending moment. Isotropic and anisotropic material characteristics in longitudinal and circumferential direction of pipeline are also considered in the proposed equations. Simplified numerical method is used to solve the generalized expressions. The comparisons of numerical results based generalized solutions and full-scale experimental results are carried out. The predicted results agree reasonably well with the experiment results. Meanwhile, the effects of corrosion shapes and locations on the ultimate load capacity are studied.

Effect of Thermal Cycling under Load on Martensite Transformation and Two-way Shape Memory Effect in a TiNi Alloy

The effect of thermal cycling under loading on martensitic transformation and two-way shape memory effect was investigated for Ti-49.8 at, pet Ni alloy. It is shown that M(s), and M(f) temperature increase with increasing the number of cycles, while A(s) and A(f) temperature decrease during thermal cycling. The total strain at and permanent strain epsilon (p) increase with increasing applied stress and number of cycles. The two-way shape memory effect can be improved by proper thermal cycling training under loading, while excessively high applied stress results in the deterioration of TWSME. The reason for the changes in martensitic transformation characteristics and two-way shape memory effect during thermal cycling under loading is discussed based on the analysis of microstructure by TEM observations.

FRACTURE LIMIT LOAD OF CONE SHAPE PART IN DRAWING PROCESS

The deformation characters and load status of the blank＇s potential fracture zone are analyzed at the moment when blank is approaching to punch comer in drawing process of cone shape part. Based on tension instability theory, the formula for calculating fracture limit load of cone shape part in drawing process is derived. Also, the formula is analyzed and verified by experiment.

Analysis of wind pressure characteristics of typical agricultural greenhouse buildings on tropical islands

Existing studies about wind pressure on agricultural greenhouse buildings concentrate on the mean wind pressure while ignoring the systematic research on fluctuating wind pressure characteristics and the influence of roof shape on the wind pressure characteristics,which are closely associated with the wind-induced damage mecha-nism.In this study,two typical agricultural greenhouse buildings on tropical islands are selected as prototypes to conduct pressure measurement experiments in the wind tunnel.Based on the wind pressure time series for the two greenhouses,the mean and fluctuating wind pressure distribution pattern and the localized high-pressure generation mechanism are analyzed.Then,the shape coefficient of the two green-houses is compared in depth to the standards from four countries.Besides,wind pressure non-Gaussian determination criteria for agricultural greenhouse buildings considering the roof shape and wind directions are proposed.Lastly,the differences in wind pressure spectra on the roofs and walls of the two greenhouses are sum-marized.The results indicate the roof shape has a significant influence on the wind pressure characteristics.Compared with the pitched roof,the vaulted roof will increase the suction effect on the windward front zone and the middle area,mitigate the suc-tion impact on the leeward roof,and weaken the wind pressure non-Gaussian charac-teristics.The experimental shape coefficient of the pitched-roof greenhouse is basically consistent with the standard from the U.S.,while that of the vaulted-roof greenhouse has some deviation from the existing standards.The results provide a theoretical basis for the wind-resistant design of agricultural greenhouse buildings on tropical islands.