This paper aims to analyze the return of the investment portfolio based on the judgment of the current market, combining the characteristics of the strategy and the situation of the applicable industry. At present, many research papers have an aperture in understanding and practical application of the above topics, because they have not been comprehensively presented from multiple perspectives such as market and industry conditions and strategic characteristics. Momentum strategy, market neutral strategy and PEG ratio are selected here, combined with representative stocks in the consumer industry, energy industry, Internet and real estate for portfolio construction. By selecting the S&P 500 as a benchmark, it is compared with the historical price trend of individual stocks and the performance of the issuing company. While individual stock prices fluctuate significantly more than the benchmark, it is still possible to judge from the price action which strategy is more suitable. Based on the above analysis, it can be intuitively seen that momentum strategies and market neutral strategies are more suitable for the moment. It has reference value for strategy selection and construction in volatile markets. The analysis of the PEG ratio is relatively simple, and the ratio is only used as the adjustment and correction of the price-earnings ratio, and there are still many defects.

Agriculture index insurance is an innovative topic that has not been well studied in the United States. North Carolina produces 1.7 billion pounds of sweet potatoes in 2020, but currently, there is no insurance to reduce the financial risk of farmers. As a result, index insurance focusing on North Carolina sweet potato farmers can be profitable. In this study, the precipitation is forecasted by the linear model using the first lag and seasonal factors. The predicted precipitations from May to September are then used to predict the yield. The precipitation model has significant factors for Season3, which represents July to September, the rainy season of North Carolina; the yield model has a significant variable of September, which is the harvest season of sweet potatoes in North Carolina. The precipitation model falls short of predicting the exact value of precipitation, but it catches the trend and seasonality. Despite the insensitivity of the precipitation model, the yield is predicted relatively accurate. The result of this study can be used to design the thresholds of the index insurance. Insurance companies can use thresholds to design insurance plans with different premiums.

As the performance of BEVs has received increasing attention in recent years as electric vehicles have become hot, the focus of our research is on a series of problems brought about by the over-engineering of EV batteries that are detrimental to the development of EVs including the charging range of EVs and the problem of excessive weight and solutions to make EVs dominate the automotive industry, we use "swap stations" and "mobile with dual charging ports in a platform with adaptive fast charging of multiple battery systems" are two strategies to solve the above problems. As a result, we found a solution to the battery over-engineering problem. In this way, electric vehicles will be able to stand out in the automotive industry and thus increase sales.

We identified five factors influencing the stock price of Tencent Music at various times in the paper. We used two mathematical techniques by collecting data on these five variables. By calculating the correlation coefficients, we were able to determine the influence of each variable on Tencent Music over different periods. Using the Linest equation in Google Sheets, we then developed a Linear regression model for Tencent Music. We used the regression model to calculate the slope, y-interpret, and predict the quarterly stock price to compare with the actual quarterly stock price. By analyzing Tencent Music's stock, we conclude the article with our perspective on the entire Chinese streaming media industry.

Mental health is essential to all of us. Research has shown that facial appearance can hold cues for symptoms of depression, and perceived mental health reflects actual mental health. However, little research shows the relationship between people's judgments of mental health conditions and facial appearances. Here we will discuss the relationship between mental health and facial appearance. We will collect photos of faces under different mental conditions and let observers rate their mental health scores. Moreover, we will also measure the observers' mental health condition to see whether people with mental illness can accurately judge faces under the same condition.

This paper seeks to examine the relationship between price discrimination and market competition before and after the outbreak of Covid-19 in the US busiest flight route, from Los Angeles airport, LAX to New York airport, JFK as a representation of the U.S. airline market. Scholars hitherto have long been focused on the effect of market concentration on price dispersion. There are two main conflicting theories that determine the relationship, the monopoly effect, and the branding effect. We analyze the air lane from Los Angeles to New York in two time periods, one from 2018 to 2020, and the other from 2020 to 2022 to see if Covid-19 changes the dominance of one effect over the other. The results of our study show that market competition has a positive effect on price discrimination during the pre-Covid period while revealing a negative effect on price discrimination after the outbreak. We conclude from the results that the branding effect dominates the LAX-JFK market before Covid-19, which means that higher competition increases the capability of a firm to charge different prices for different segments of customers whereas the monopoly effect overturns after the Covid-19 pandemic.

With the internet and technology development, the utilization rate of short video platforms has gradually increased, and online shopping has become very common. On September 20, 2016, Tiktok short video platform was launched. A TikTok mall is a delivery tool provided by Tiktok e-commerce for merchants. The platform reduces the threshold for merchants to meet the requirements and implements a comprehensive opening policy to obtain more user traffic. Inevitably, lowering the threshold brings the disadvantage of merchants selling fake and inferior products, leading to the lemon for the market and significantly impacting the platform atmosphere and user traffic. Based on the idea of mixed strategy and a journal about the online game theory of product quality, this paper adds more variables, taking into account the negative impact of Tiktok's actual scheme policy and lemon market. Constructing a game theory model including merchants and Tiktok regulatory department, analyze its nash equilibrium and derivative of each variable. Finally, find out that the lemon market exists on the Tiktok platform. Second, the higher cost of high-quality firms leads to strengthening supervision to prevent the low-quality firms from being driven out of the market. Third, the lower profit of low-quality goods, the merchants prefer to sell high-quality goods. The strategies selected by the regulatory authorities on the Tiktok platform and the strategies of the merchants are influenced by the production costs of different quality, the regulatory costs, and the rewards obtained from the efforts made by the regulatory authorities in sampling inspection. These factors will also influence their profits. This paper will prove the conclusion with accurate data.

Catering to the development wave of Internet +, The ride-hailing service, which combines public transport with the Internet's positioning system, has attracted many users. After that, many online car-hailing platforms represented by "Didi Dache" and "Cao Cao Chauffeur" emerged, which achieved great success through online publicity. Its appearance greatly facilitates people's life, and it can also meet the needs of different passengers through personalized services. Nowadays, the ride-hailing industry has entered a stage of steady development, but many problems have been exposed along with the development, and most people focus on safety issues. The development of ride-hailing has changed people's concept of life, so it is also caught in the conflict and contradiction of classic cars, like many new things. However, with the launch of "Guiding Opinions on Deepening Reform and Promoting the Healthy Development of Taxi Industry" and "Interim Measures for the Management of Online Booking Taxi Service", the state has also shown its support and affirmation for the business model of the online booking car industry. This study will explore the market development structure of ride-hailing and will focus on the current problems and solutions of the ride-hailing industry.

This paper mainly focuses on one Strategy–Purchasing Power Parity. PPP is a value strategy that shows whether a currency is overvalued or undervalued based on the market prices of a specific good in different nations, and investors believe that the currency will get back to its fair value in the long run so that they would be long the undervalued currencies, and vice versa. This strategy is one of the two presentations from the class presentations. Furthermore, it was well developed in its modern form by Gustav Cassel in his article Abnormal Deviations in International Exchanges.

The international trade and industrial structure since the industrial revolution have changed significantly featured with a booming trade volume and unprecedented speed of industrialization. However, under the current of industrial process of western nations, the third-world countries, are experiencing a de-industrial process. Through industrialization and de-industrialization, the structure of the world was significantly changed, and the world was later classified as the developed and developing nations. This classification still works for current world order. Thus, tracing the reason that the process of world classification is vital, which could better enhance the understanding of contemporary world. This paper aims to analyse the reasons for the de-indudstrialization in the peripheries with a historical and econometric review.