Military Academy

About: Military Academy is a based out in . It is known for research contribution in the topics: Population & Fuzzy logic. The organization has 2478 authors who have published 3003 publications receiving 33188 citations.

Method of planning construction projects, taking into account risk factors

Abstract: This paper presents an original method of planning construction projects, taking into account the influence of potential risk factors. The method is called the Method of Construction Risk Assessment (MOCRA). According to this method, first the material-financial plan of a project (a construction project in the example provided) is analyzed. Then risk factors are identified, taking into account the project’s specificity. The end result of this stage is a list of risk factors. In the third stage the risk is reduced or minimized where possible. Finally, the specified risk factors are quantified, which is a difficult task. The effectiveness of the risk assessment depends on how thoroughly this task is carried out. Since point scale assessment of risk does not appeal to engineers, in MOCRA quantified risk is allocated in the material-financial plan. Thanks to this, one can prepare contingency plans, i.e. plans (action variants) to be implemented when particular risk factors occur. Having completed the project, one can use MOCRA to check the accuracy of the assessment (forecast) and select the best contingency action variant, whereby the method’s effectiveness in planning future projects is improved.

Hybrid encryption algorithm (HEA) based on chaotic system

Abstract: In this paper, we present a very simple and efficient hybrid encryption algorithm based on block and stream ciphers using chaotic systems. Due to the specific characteristics of chaotic systems which are described by a set of nonlinear deterministic dynamic equations, chaos-based encryption achieves a very high level of security. The chaotic system used in this algorithm is Chirikov Standard Map, which is chosen in order to further minimize the encryption time. The proposed scheme adopts two main operations one to generate pseudorandom data block that will be used for stream cipher, and the second to create substitution and permutation tables in initial step and perform rounds for confusion and diffusion processes in block cipher. Some cryptographic tests and metrics are applied to measure the degree of security and analyze the performance of the encryption scheme. The evaluation and simulation analysis indicate that our proposal possesses excellent cryptographic properties; it is extremely sensitive to the small change in secret key, resists against common cryptanalytic attacks, has a high speed and easy to implement.

Efficient dynamics analysis of large-deformation flexible beams by using the absolute nodal coordinate transfer matrix method

Abstract: This paper describes an efficiently computational method for dynamics simulating of planar multibody system with flexible beams undergoing large deformations by combining the absolute nodal coordinate formulation (ANCF) and the transfer matrix method (TMM). Firstly, according to ANCF and the geometrically nonlinear theory, the two-dimensional shear-deformable beam element and its dynamic equations of motion are presented. Then according to TMM and the dynamic equations of beam elements, by defining the new state vectors and deducing the new transfer equations of elements, an efficient computational method named as ANC–TMM, is presented for dynamics of planar multibody system with flexible beams undergoing large deformations. Compared with the ordinary dynamics methods, the proposed method combines the strengths of TMM and ANCF. It does not need the global dynamic equations of system and has the low order of the system matrix and high computational efficiency. This method can be extended to solve the nonlinear dynamics problems of general flexible multibody systems undergoing large deformations. Formulations as well as a numerical example of a flexible four-bar linkage mechanism are given to validate the method.