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In this paper, the aim is to simulate night-sky images for use in star-sensor designing software. For this purpose, a comprehensive and precise algorithm was developed to simulate night sky images based on the ideal pinhole method and the use of Gaussian distribution functions. Then, in order to create more realism, sources of random and systematic errors, the elongated images due to the high dynamics of the platform, as well as the asymmetric back-lighting of the moon, the sun, and the planets of the solar system have been simulated. Finally, considering the importance of realism in the problem-solving simulation approach, the use of precision ray tracking method as an alternative to the ideal pinhole method is suggested.

In this research, the problem of optimal trajectory design of an upper stage is considered for satellite injection into Geostationary orbit in 3-Dimensional space. The optimal multi-burn trajectory is obtained based on Euler-Lagrange theory with minimum fuel consumption criteria. Instead of using switch function for obtaining the switching times, which complicates the numerical solution of the optimal control problem, the presented algorithm uses a simple and optimal process to find the burn and coast times. To solve the tow point boundary value problem, an improved indirect shooting method with high performance is used which in addition to having higher precision, converges very fast to the desired condition.

Both accounting education and the practice of accounting has been in a state of disarray in developing countries for a long time. Given the desperate need for economic development in these countries and the role that accounting information plays in economic decisions (at both micro and macro levels), the problems associated with the weak or non-functioning accounting systems in these countries is of grave concerns to all interested parties. In these countries, there is a very strong need to develop an accounting system (or improve the existing ones) that would be capable of producing the information needed for policy setting, planning, programming, and control of economic activities. Unfortunately, up to now, not much attention has been devoted to how to organize or improve such systems. It could be claimed that the few research done in this area, have not focused on the real issues and instead, have looked at the problem from a peripheral views. For example, these research have dealt with issues like the number of accountants, the quality of accounting workforce, and alike. What seems needed in developing countries is to design and implement an improved infrastructure for their accounting system. Restructuring of I or designing a new infrastructure appears to he the only effective remedy for the serious problems they face. The implementation of the appropriate infrastructure would result in an improved quality of: accounting information, the accounting technology, and the accountants. It would also be able to satisfy the demand for accounting information.