Research On Prices Fluctuation And Transmission Of Chinese Hog Market Under Multi-scale Perspective

In recent years,due to the continuous accumulation of internal and various economic risks and natural risks in the hog industry,the price of the hog market in China has fluctuated drastically,which is characterized by large short-term fluctuations and obvious long-term upward trend.It has a significant “pig cycle” phenomenon,sequence itself also presents non-stationary,non-linear complex features.The extraordinary fluctuations in the market price of live pigs have caused a series of chain reactions,which have adversely affected the healthy development of the national economy and aroused the attention of the whole society.In this context,as the multi-scale analysis method can deal with nonlinear and non-stationary time series,it can reveal the intrinsic features from the perspective of combining the time domain and the frequency domain.In particular,the multi-scale analysis method can decompose the non-stationary and nonlinear hog market price series into sub-price sequences with different time scales and frequency characteristics but relatively stable characteristics,accurately reflecting the fluctuation law of each scale,and profoundly exposing the structural characteristics of price fluctuations in the hog market,and is more helpful to analyze the price transmission mechanism of the pig industry chain.Furthermore,combined with the mechanism of the external events of the hog industry on the market price of live pigs,the transmission mechanism of the international market to the price of the hog market in China is discussed from a multi-scale perspective.The above research has important theoretical and practical significance for promoting the stable and healthy development of the hog market,stabilizing the domestic food consumption price,and promoting the better and faster development of the agricultural economy.The main contents of this paper are as follows:First,multi-scale perspective study on the price fluctuation of China's live pig market.(1)Using the integrated empirical mode decomposition technique is used to decompose the original hog price series from a multi-scale,and use the recombination algorithm to reconstruct the decomposed eight mode function and trend term into the three components,such as high-frequency wave component caused by the short-term supply and demand imbalance in the hog market,the low-frequency fluctuation component caused by major events and the long-term trend component determined by economic fundamentals.(2)Comprehensively use BP structure mutation test and event analysis method to analyze the impact of regulation policy on hog price from a multi-scaleperspective.The results also indicated that the regulatory policies on hog market mainly influenced the low fluctuation component,and have limited effects on the trend and high fluctuation components.Second,the study on the price transmission of China's hog industry chain from a multi-scale perspective.(1)Using the integrated modal decomposition technique to analyze the transmission relationship among China's hog industry chain prices from a multi-scale perspective,it is found that the piglet price,pig price and pork price show different volatility characteristics and relationships at different time scales.(2)On this basis,the directed acyclic graph,structural vector autoregressive model and time difference correlation coefficient are used to comprehensively analyze the conduction effects of the three prices on different time and frequency scales.The results show that in the short term,the fluctuation of hog price and pork price can be transmitted to piglet price;There is a two-way conduction relationship between hog price fluctuation and pork price fluctuation.In the medium and long term,there is a two-way conduction process between piglet prices and pork prices in the medium and long term,but pork prices are more strongly transmitted to piglet prices.The price of live pigs has a one-way transmission effect on piglet prices.There is a two-way conduction process between hog prices and pork prices,but the price of hog is more transmitted to pork prices.Third,the transmission of international market on China's pork price based on multi-scale analysis.(1)The domestic pork price decomposition is recombined into high-frequency fluctuation component,low-frequency fluctuation component and long-term trend component through integrated modal decomposition technology.Combined with the fluctuation characteristics of each component,it is found that the low-frequency fluctuation component has the highest interpretation of domestic pork price,followed by long-term trend component.(2)In turn,the directed acyclic graph technique and the structural vector autoregressive model based on directed acyclic graph are used to analyze the major events such as the international influence factors of low frequency components of domestic pork prices.The results show that the international pork market price has little explanation for the low frequency component of domestic pork prices.However,the price of imported pork to the shore has a long-term transmission effect on the low-frequency component of domestic pork prices,which can explain about 8% of fluctuations.