Analysis of business development of a technology commercial company

This thesis centers on analyzing SHEIN, one of the giant technology commercial companies all over the world. It is from China but only develops business abroad. SHEIN has got an extraordinary achievement in this decade and that is inextricably linked to its unique operating model which is composed of six important parts that are the business gene of SHEIN, the supply chain, the modern digital system, the marketing methods, the logistics and the industry environment. These six different parts are interlocked and closely linked to each other. Specially, different from other leading brands in the industry such as ZARA and Amazon, SHEIN has quickly captured the fast-fashion market of the younger generation with cheaper prices and faster logistics supply chain. So far, SHEIN has its own design line of products on the website and has also expanded other categories of products like household products. However, a large part of SHEIN’s success has been brought about by this era. With the development of the Internet economy, people from the younger generation have an increasing pursuit of fashion. The rapid rise of online marketing and social media make it easier to promote the brand reputation all over the world. In conclusion, it can be said that SHEIN is in line with the trend of this era and this era has achieved SHEIN’s business model. However, one corn has two sides, there is a voice of doubt here. How far can SHEIN go in the future? Whether it is to make quick money in a few years? It is undeniable that SHEIN does have a lot of problems, and although they have been well solved so far, if the solutions are sustainable in the long run or not and SHEIN would face them positively with their young and energetic company cultur

Vibration signal de-noising based on empirical wavelet transform autocorrelation analysis

In diesel engine fault diagnosis, non-stationary vibration signal is easily disturbed by strong noise. In view of the shortcomings of empirical mode decomposition (EMD) and wavelet transform in de-noising, a de-noising method is proposed, which is Empirical Wavelet Transform (EWT) autocorrelation analysis. Taking advantages of EMD and wavelet transform, the Fourier spectrum is adaptively divided by EWT, and the intrinsic mode components of different frequency are extracted through constructed wavelet filter, and the method can effectively eliminate modal aliasing and solve adaptive problems in wavelet de-noising. At the same time, autocorrelation analysis can make the random noise decay to zero, and the modal components with high frequency random noise are dealt by autocorrelation analysis. The method is used to de-noising and compared the de-noising effect of EWT and EMD. Results show that the method can effectively decompose the intrinsic mode component with less number, and there is no false mode, and the de-noising effect is better than EMD de-noising. The method is feasible and effective in de-noising by vibration signals of diesel engine

Spin incoherent liquid and interaction-driven criticality in 1D Hubbard model

A rigorous understanding of the spin incoherent Tomonaga-Luttinger liquid (TLL), which displays solely a propagating charge mode but not a spin mode, and the interaction-driven quantum phase transitions in one-dimensional (1D) systems still remain elusive. In this Letter, we report the universal properties of spin incoherent TLL and interaction-driven criticality of the 1D repulsive Hubbard model by means of fractional charge and spin excitations, asymptotic of correlation functions as well as the lattice Contact. We build up an essential connection of Contact susceptibilities to the variations of density, magnetization and entropy with respect to the interaction strength, providing a rigorous understanding of interaction-driven phase transitions, Mott insulator and quantum cooling in the model. These relations hold true for higher dimensional systems.Comment: 4 figures 6 page

Exact results of one-dimensional repulsive Hubbard model

We present analytical results of fundamental properties of one-dimensional (1D) Hubbard model with a repulsive interaction, ranging from fractional excitations to universal thermodynamics, interaction-driven criticality, correlation functions, Contact susceptibilities and quantum cooling. Using the exact solutions of the Bethe Ansatz equations of the Hubbard model, we first rigorously calculate the gapless spin and charge excitations, exhibiting exotic features of fractionalized spinons and holons. Based on the analysis on the fractional charge and spin excitations, the spin-incoherent Luttinger liquid with only the charge propagation mode is elucidated by the asymptotic of the two-point correlation functions with the help of the conformal field theory. Near quadruple critical point, we then further analytically obtain the thermodynamical properties, dimensionless ratios and scaling functions near quantum phase transitions in terms of chemical potential, magnetic field and interaction. In particular, we determine additivity rules of spin and charge susceptibilities, and derive explicit forms of thermodynamics of spin-incoherent Luttinger liquid. Finally, in order to capture deeper insight into the Mott insulator and interaction driven criticality, we further study the double occupancy and its associated Contact and Contact susceptibilities through which an adiabatic cooling scheme upon the quantum criticality is introduced.Comment: slight changes, 50 pages +18 figures, new analytical result

Engine fault feature extraction based on order tracking and VMD in transient conditions

A method based on order tracking and Variational Mode Decomposition was proposed to solve the problem of non-stationarity and background noise in the vibration signal of engine. For the vibration signal of diesel engine crankshaft bearing fault and Connecting rod bearing of gasoline engine, the non-stationary signal in the time domain was converted into a pseudo stationary signal on the angular domain based on order tracking. Then the reconstructed signal was decomposed by several components by VMD, and the component that contains fault information was selected. The three-dimensional spectral array of order, speed and power spectrum was calculated, and the fault feature was extracted. The effectiveness of the proposed method is verified by simulation and experiment