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The purpose of this paper is to study the closed-loop guidance algorithm for launch vehicles in an atmospheric ascent phase and present a numerical trajectory reconstruction algorithm to satisfy the real-time requirement of generating the guidance commands.

An optimal control model for an atmospheric ascent guidance system is established directly; following that, the detailed process for necessary conditions of the optimal control problem is re-derived based on the calculus of variations. As a result, the trajectory optimization problem can be reduced to a root-finding problem of algebraic equations based on the finite element method (FEM). To obtain an accurate solution, the Newton method is introduced to solve the roots in a guidance update cycle.

The presented approach can accurately and efficiently solve the trajectory optimization problems. A moderate number of unknowns can yield a good optimal solution, which is well suited for the open-loop guidance. To meet the requirements of the rapidity and accuracy for the close-loop guidance, the fewer number of unknowns is artificially chosen to reduce the calculation time, and the on-board trajectory planning strategy can increase the precision of the optimal solution along with the decrease of time-to-go.

The closed-loop guidance algorithm based on an FEM can be found in this paper, which can solve the optimal ascent guidance problems for launch vehicles in the atmospheric flight phase rapidly, accurately and efficiently.

This paper re-derives the necessary conditions of the optimal solution in a different way compared to the previous work, and the closed-loop guidance algorithm combined with the FEM is also a new thought for the optimal atmospheric ascent guidance problems.

The purpose of this paper is to empirically study the impact of the coronavirus disease 2019 (COVID-19) on food prices in China and provides policy implications for crisis management for other countries who are still under the crisis of COVID-19 and for the future in China and beyond as well.

This paper first designed a theoretical model of market equilibrium, which shows that the impact of COVID-19 on food prices is linked to the impact difference on demand and supply in response to the COVID-19 crisis. Then we collected the representative prices data for four major food products (rice, wheat flour, pork and Chinese cabbages) from three provinces (Shandong as a producing base, Beijing as a consumption base and Hubei as the epicenter), and set up an iGARCH model.

(1) No significant impact on rice and wheat flour prices, (2) significantly positive impact on cabbages prices and (3) various impact on pork prices. Note that the outbreak and the severity of COVID-19 have different impacts. The outbreak itself may have a relatively large impact on pork and cabbage prices, which may result from social panic, while the magnitude of the impact of severity is relatively small, and some are negative, perhaps due to more reduced demand during the quarantine.

China always puts food security in its prior position of policy agenda and has been preparing for the worst scenario of the food security crisis. In the anti-COVID-19 campaign, China's local governments developed many measures to ensure food provision for each consumer. Hence, the impact of COVID-19 on food prices is minor. However, the outbreak of COVID-19 crisis could cause social panic in some scenarios where consumers may hoard food. Eventually, it may form a vicious cycle to push up food prices. This will be a challenging policy issue in crisis management for almost all governments.

This paper provides empirical evidence on the impact of COVID-19 on food prices in China. China has basically contained the COVID-19 in the whole country, and no major food crisis occurred during this process. The results will provide information on crisis management for other countries that are still under the COVID-19 crisis, and for future China and beyond.

Modelling methods can be helpful for understanding vibrations of beam structures including cracks, as well as for early detection of crack. This study aims to provide an analytical modelling approach for a cantilever beam considering a slant vertical crack along its height. However, previous uniform crack methods cannot be used for describing this case. The results from the analytical, finite element (FE) and experimental methods are compared to verify the vibration problem.

A massless rotational spring model is adopted to describe the crack. An extended method based on the calculation method for a uniform vertical edge crack is proposed to obtain the stiffness of the slant case. The beam is divided into a series of independent thin slices along the beam height. An Euler–Bernoulli beam model is applied to formulate each slice. The crack in each slice is considered as a uniform one. The transfer matrix method in the literature is used to obtain the beam vibration frequencies and mode shapes. Influences of crack location and sizes on the natural frequencies for the cantilever beam, as well as the mode shapes, are analysed. An established FE model and test results in the listed references are used to validate the developed method.

The numerical results show that the rotational stiffness at the cracked section and the natural frequencies of the beam decrease by increasing the crack sizes; the natural frequencies for the beam are greatly influenced by the crack sizes and location; the first natural frequency decreases with the distance from the beam fixed end to the crack location; the value of the first natural frequency reaches a minimum value when the crack is at the beam fixed end; the value of the second natural frequency is a minimum value when the crack is at the beam middle; and the value of the third natural frequency is a minimum value when the crack is at the beam free end. Saltation is observed in some mode shapes at the crack location, especially for larger crack depths; but, the mode shapes of the beam are slightly influenced by the vertical crack.

This study gives a useful analytical modelling method for free vibration analysis for the cantilever beam with a vertical crack, which can overcome the disadvantages of the previous uniform crack methods.

The study uses machine learning techniques to cluster regional retail egg prices after 2000 in China. Furthermore, it combines machine learning results with econometric models to study determinants of cluster affiliation. Eggs are an inexpensiv, nutritious and sustainable animal food. Contextually, China is the largest country in the world in terms of both egg production and consumption. Regional clustering can help governments to imporve the precision of price policies and help producers make better investment decisions. The results are purely driven by data.

The study introduces dynamic time warping (DTW) algorithm which takes into account time series properties to analyze provincial egg prices in China. The results are compared with several other algorithms, such as TADPole. DTW is superior, though it is computationally expensive. After the clustering, a multinomial logit model is run to study the determinants of cluster affiliation.

The study identified three clusters. The first cluster including 12 provinces and the second cluster including 2 provinces are the main egg production provinces and their neighboring provinces in China. The third cluster is mainly egg importing regions. Clusters 1 and 2 have higher price volatility. The authors confirm that due to transaction costs, the importing areas may have less price volatility.

The machine learning techniques could help governments make more precise policies and help producers make better investment decisions.

This is the first paper to use machine learning techniques to cluster food prices. It also combines machine learning and econometric models to better study price dynamics.

The primary purpose of this study is to investigate the influence of tourists' perceived value, satisfaction and behavioral intention on the development of Lipu Yi costume culture to promote the development of intangible cultural tourism and better construct a model of the influencing factors of Lipu Yi costumes in the development of intangible cultural heritage tourism.

The study site is the intangible cultural district of Panzhihua, Sichuan Province, China. This study examines the interrelationships between tourists' perceived value of experience, behavioral intention and satisfaction as the tourists relate to Lipu Yi costume and intangible cultural heritage tourism. A sample of 225 tourists who had visited Panzhihua at least once was selected for the study.

All seven of the survey's hypotheses were supported. Therefore, this study concludes that tourists' perceived value, satisfaction and behavioral intention directly affect the development of intangible cultural tourism and significantly positively impact the growth of Lipu Yi costumes culture. Descriptive analysis, confirmatory factor analysis (CFA) and structural equation modeling (SEM) investigation methods were used.

This paper analyzes tourists' perceived value of Lipu costume culture and tourists' satisfaction and behavioral intention during the tourism process. This study provides a more in-depth understanding of the relationship between Lipu Yi costume and non-heritage tourism factors. Practical methods and approaches are sought to further develop Lipu Yi costume non-heritage tourism.

This study examines the impact of formal and informal institutional distances on the foreign ownership strategies of emerging market firms (EMFs).

This is an empirical study relying on two sets of data collected over two time periods, 2006–2008 and 2017–2019, for publicly-listed Chinese companies.

Greater formal institutional distances in the host and home countries make EMFs less likely to use joint ventures (JVs), while greater informal distances make EMFs more likely to use the JVs. When both formal and informal institutional distances are high, the use of JVs is more likely. These results are affected by the goal of the foreign direct investment (FDI) project, with strategic asset-seeking (SAS) FDI projects favoring the use of wholly owned subsidiaries (WOSs).

This study relies on cross-sectional data from publicly-listed Chinese companies, which may limit the generalizability of the findings.

EMFs investing in advanced countries should carefully assess the tradeoffs between transactional cost efficiency and legitimacy in making their foreign ownership decisions. If the goal is to access strategic assets, EMFs should consider WOSs to ensure the transfer of strategic assets and create value for the parent company.

The findings show that formal and informal distances between institutions have different impacts on foreign ownership strategies, providing empirical evidence for the need to balance conflicting cost-efficiency and legitimacy considerations when businesses make such strategic decisions. The authors show how this balance depends on the goal of the FDI project.

Despite the fact that user participation (UP) has been highlighted as an important aspect in innovation, previous findings on its relationship with service innovation performance (SIP) are inconsistent. This study aims to investigate the relationships among UP, knowledge management capability (KMC) and SIP, especially in the digital age, inspired by the theories of knowledge-based and absorptive capacity.

Based on a sample of 252 Chinese e-commerce enterprises, this study adopts a hierarchical regression analysis and bootstrap method to test the theoretical framework and research hypotheses.

UP and KMC have positive effects on SIP, respectively. KMC plays a mediating role in the effect of UP on SIP. Furthermore, the intermediary role of KMC varies in different sub-paths between UP and SIP.

First, this study provides some explanations for inconsistent arguments on the relationship between UP and service innovation. Second, with the consideration of specific dimensions of UP and SIP, the mediation role of KMC varies in different sub-paths has been recognized, which provides a deeper understanding of the relationship between UP and SIP. Third, this study opens the discussion about how to realize SIP more effectively in the digital age, advancing theoretical and practical developments on service innovation.

Various factors may influence project finance when a multi-sourced debt financing strategy is used for financing capital investments, in general, and public infrastructure investments, in particular. Traditional indicators lack comprehensive consideration of the influences of many internal and external factors, such as investment structure, financing mode and credit guarantee structure, which exist in the financing decision making of BOT projects. An effective approach is, thus, desired. The paper aims to discuss these issues.

This paper develops a financial model that uses an interval number to represent the uncertain factors and, subsequently, conducts a standardization of the interval number. Decision makers determine the weight of each objective through the analytic hierarchy process. Through the optimization procedure, project investors and sponsors are provided with a strategy regarding the optimal amount of debt to be raised and the insight on the risk level based on the net present value, as well as the probability of bankruptcy for each different period of debt service.

By using an example infrastructure project in China and based on the comprehensive evaluation, comparison and ranking of the capital structures of urban public infrastructure projects using the interval number method, the final ranking can help investors to choose the optimal capital structure for investment. The calculation using the interval number method shows that X2 is the optimal capital structure plan for the BOT project of the first stage of Tianjin Binhai Rail Transit Z4 line. Therefore, investors should give priority to selecting a capital contribution ratio of 45 per cent for this investment.

In this paper, some parameters, such as depreciation life, construction period and concession period, are assumed to be deterministic parameters, although the interval number model has been introduced to analyze the uncertainty indicators, such as total investment and passenger flow, of BOT rail transport projects. Therefore, more of the above deterministic parameters can be taken as uncertainty parameters in future research so that calculation results fit actual projects more closely.

This model can be used to make the optimal investment decision for a project by determining the impact of uncertainty factors on the profitability of the project in its lifecycle during the project financial feasibility analysis. Project sponsors can determine the optimal capital structure of a project through an analysis of the irregular fluctuation of the unpredictable factors in project construction such as construction investment, operating cost and passenger flow. The model can also be used to examine the effects of different capital investment ratios on indicators so that appropriate measures can be taken to reduce risks and maximize profit.

This paper aims to re-examine the role of institutions in the rise of made-in-China multinationals. Specifically, the paper seeks to understand how changes in the global environment, especially global financial crisis, have solidified the Chinese government's role in pushing and encouraging Chinese firms to engage in outbound foreign direct investment (OFDI) activities.

This is a conceptual paper. The analysis is based on a large number of publicly available sources, including research papers, government documents, and reports. The paper strives to triangulate the validity of the data with multiple sources.

The study finds that while the role of the state in China has been evolving since the start of the economic reforms in 1978, by no means has it been lessened. Instead, the state has asserted its role specifically to grow Chinese multinationals in size and in number, by leveraging the financial resources accumulated over the last 30 years, by taking advantage of the cheap assets made available globally by the recent financial crisis and by institutionalizing its “Go Global” strategy.

The study implies that the role of the state will be further solidified through China's national goal of enhancing competitiveness via knowledge acquisition through OFDI and simultaneously, multinationals’ OFDI initiatives and strategies will be reinforced by the state's economic policies and goals while their commercial interests will take on an increasing importance in the global marketplace and their behavior will co-evolve with and be reshaped by local, national, and international environments. The paper suggests that future studies employ co-evolutionary theory to investigate the role of state-owned enterprises (especially the functions of their CEOs) as well as non-state actors in shaping the institutional framework in China. Future studies should verify some of the ideas with empirical data and strive to triangulate different data sources to increase data quality.

The study also provides implications to Chinese policy makers on how to balance the government's role as conductor, enabler, protector, and constrainer while allowing Chinese multinationals to integrate into the global market for the benefit of both China and the world economy.

This study represents an original contribution to this topic. The research contributes to the study of globalization of Chinese enterprises by exploring the renewed dynamic relationship between the state and the firm after the 2008 global financial crisis.

Undoubtedly, coronavirus (COVID-19) pandemic has released unprecedented disruptions and health crisis on people and activities everywhere. The impacts extend to public–private partnership (PPP) arrangements in the construction industry. Concomitantly, PPP pacts are contributing to combat the pandemic. However, literature on the PPP concept in the COVID-19 era remain under-researched. This study aims to review the current literature on PPPs in the COVID-19 pandemic and present the key themes, research gaps and future research directions.

In this study, 29 highly relevant literature were sourced from Web of Science, Scopus and PubMed search engines within the systematic literature review (SLR) methodology. With the aid of qualitative content analysis, the 29 articles were critically analysed leading to the extraction of hot research themes on PPPs in the coronavirus pandemic.

The results of the SLR produced eight themes such as major changes in PPP contracts, development of the COVID-19 vaccines, economic recession, facemasks and testing kits, governance and sustainability of PPPs. In addition, the study reveals seven research gaps that need further investigations among the scientific research community on mental health and post-pandemic recovery plans.

The articles selected for this review were limited to only peer-reviewed journal papers written in English excluding conference papers. This restriction may have taken out some relevant literature but they had insignificant impact on the overall outcome of this research.

To improve the understanding of practitioners in the construction industry on key issues on PPPs in the COVID-19 pandemic, the study provides them a checklist of relevant themes.

As a novel literature review relating PPPs to the coronavirus, it sets the foundation for further research and contributes to practical measures to control the virus.