Simulating rise and fall cycles of Vietnam empires

The life cycle pattern of empires is pervasive worldwide,and this is caused by multiple factors.In the history of Vietnam,there are totally about ten empires or dynasties,which have aggregately lasted for more than one thousand years.Here,we apply the life cycle model and agent-based modeling to uncover the underlying mechanisms of the life cycle pattern for Vietnam empires.Macroscopically,the man-land relationship greatly shapes the life cycle pattern of traditional agricultural empires.The balancing process between land and population is critical for the empires.The relationship between incomes and costs has determined the actions or strategies of the social members or individuals.It suggests that our optimal solutions and simulations have perfectly matched the real history of Vietnam.Under three optimal solutions,the distributions of simulated and real empire durations in history can be well-matched,in terms of both discrete(histogram)and continuous forms(kernel density).It indicates that the history of human society is a dynamic process,which is determined by certain evolutionary rules and regulations.Therefore,we are able to back-calculate,simulate,and even predict the future of empires or countries.

A COMPUTER MULTIMEDIA BOOK OF MECHANICAL DRAWING

This report gives a view of a computer multimedia book of mechanical drawing. This electronic book is developed under Windows and Chinese Star to form an integrated system on a CD-ROM. In the electronic book, graphics, images, 3D animation, audio, video and text techniques of computer multimedia are applied. The techniques, methods, contents and purpose of developing this system are introduced.

A new production component method for natural gas development planning

Based on an analysis of the limitations of conventional production component methods for natural gas development planning,this study proposes a new one that uses life cycle models for the trend fitting and prediction of production.In this new method,the annual production of old and new wells is predicted by year first and then is summed up to yield the production for the planning period.It shows that the changes in the production of old wells in old blocks can be fitted and predicted using the vapor pressure model(VPM),with precision of 80%e95%,which is 6.6%e13.2%higher than that of other life cycle models.Furthermore,a new production prediction process and method for new wells have been established based on this life cycle model to predict the production of medium-to-shallow gas reservoirs in western Sichuan Basin,with predication error of production rate in 2021 and 2022 being 6%and 3%respectively.The new method can be used to guide the medium-and long-term planning or annual scheme preparation for gas development.It is also applicable to planning for large single gas blocks that require continuous infill drilling and adjustment to improve gas recovery.