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Time difference of arrival (TDOA) passive localization is a kind of signal source localization method. There are two types of solution methods, the drawing methods and the calculating methods. The calculating methods are divided into analytic-calculating methods and numerical-calculating methods. As a kind of analytic calculation method, the universal unconstrained nonlinear programming based optimization model of TDOA passive localization was proposed in this paper, its solving algorithms were also discussed. The numeric results shows that the Pattern Search Method has been proved to be able to solve the optimization problems of TDOA localization with only small part of non-convergent points and the Simple-Grid method was the general solution of TDOA optimization problems. Also the localization errors were independent of the order number of the objective function had been obtained.

The application security of information systems is essentially to ensure the safety of business processes elements (BPEs) supported by information system, that is, by implementing appropriate security measures to ensure that the business processes operate in a well-defined and logical manner. A security model based on business process is proposed in this paper, through defining basic safe attributes of business process, also the security target recognition and consistency test of the model are given.