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Recipe: How To Translate A Recursive Function Into An Implicite One

In order to determine the runtime of a recursive function, it is helpful to translate this function into an implicite one. This blog post illustrates a straight-forward approach, intuitively – with exactly 5 steps on a small example. This approach is also applicable for almost every recursive function.

Why Tho?

The reason to resolve a recursive function lies in the analysis and application. When interested in runtime analysis, the implicite function will serve as a guidance for the total runtime of the recursive function. When interested in application, the implicite function will have the same

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An (in-)formal Introduction To Attack Defense Trees

It is widely known that the security of a system seen as property is not static. Therefore, there cannot exist a general algorithm deciding whether or not a given system is secure in its sense. IT-Security Architects and Engineers are stuck with persistent research of bug reports of the technology the respective enterprise is using. In the industry, IT security is one use case of many others. The types of systems to examine vary depending on context. For instance, the construction of a museum is considered as a system and it is of interest to guarantee that the objects, stored in this kind of facility, are considered safe and sound. In consequence, it is urgent to establish a formal model for system description and security evaluation. There are various challenges to overcome, for instance:

  • What are the best defensive measures to invest in?
  • How can it be decided whether a defensive measure from the past is still necessary?
  • How can newly discovered attacks be efficiently documented?
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A Few Words On Algorithm Complexity

One of the key properties of a given algorithm is its complexity. A computer scientist is interested in the adequacy of the algorithm runtime relative to the size of the input. While there exist sharp runtime lower bounds for any given algorithm, for upper bounds however, the sky is the limit. It depends on the quality of optimization.

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