Advanced Defense Science and Technology
Year:2015 | Volume:5 | Issue:4|Papers Count:7

In this paper, robust unit commitment with defensive viewpoint and probability model of plants inaccessibility have been surveyed. From strategic and military viewpoint, due to the possibility of a military attack, the electrical energy operation depends on arrangements codification and utilization of effective planning in the production part. In a sample power network, because of the variable possibility of attack, some plants have different probability of inaccessibility.Thus, technique of identification and weight assignment has been employed to find sensitive power plants. In the proposed scheme, random contingencies, including sudden unit outage due to military attacks have been considered with scenarios taking into account the probability of their occurrence. In this paper, probability values of plants inaccessibility have been extracted by presenting a comprehensive model. The proposed method has been implemented on IEEE standard 30 bus system. Comparative analysis results indicate that to reach a secure plan, preserving an optimal production level from power plants to maintain feeding continuity is inevitable.

About a quarter of a century has passed since the IRAK-IRAN war but unfortunately, some areas of the country still remains contaminated by mines and unexploded bombs and sometimes irreparable damage is inflicted. Due to the limitation of magnetic mine detectors, penetration depth should be estimated with reasonable accuracy. In this paper, the mathematical model of the bomb motion in the air and soil is written. The bomb motion is simulated based on TM and military handbook with MATLAB. Then UXO penetration depth in Azadegan oilfield was Investigated as a case study and simulation results are compared with MIZUHO results. The effect of the bomb angle of attack in the penetration depth is also determined. Finally, regarding all effectives parameters, the correct depth is estimated and invalidity of MIZUHO results is shown. Subsequent excavations carried out in the field and non-observation of UXO in more than six meters deep proved obtained results.

Cryptography is one of the most important ways of information security in passive defence. In this paper, a new image encryption method using reversible and hybrid cellular automata is presented. Since four most significant bits of each pixel have main information of an image, a hybrid cellular automata encrypts this bitst. Then, a reversible cellular automata are applied to whole of the pixels and finally, cellular automata scrambles the image bits. Using a series of standard tests, the suggested method was compared with some other methods to assess the efficiency of the algorithm.The experimental results show that the suggested algorithm has satisfactory performance in terms of quantitative assessment from some other schemes.

Filtration of toxic materials were examine by two different laminated filterazied fabrics consisted of activated carbon polyurethane foam and carbon fabric laminated at the same conditions. Functionalized characteristics of two samples such as weight, thickness, force tearing, bending, active carbon collapsing, air permeability and absorbed dose of toxic simulant, i.e.1, 3-dichloropropane in vapor/vapor and liquid/vapor phases according to the standard methods were investigated. The obtained results indicated that capability and efficiency of carbon fabric laminated has advantage over the activated carbon polyurethane foam, also it is more suitable to be used in sealed area.

With the development of energy converters and storages, the issue of multi-carrier energy hubs has been considered. At these hubs, various forms of energy such as electricity, gas and heat can be converted to one another through the converters. Given the substitution possibility of different forms of energy, reduce the cost and increase reliability of power supply system, which are the main advantage of energy hubs. In this paper, an energy hub including multiple sensitive loads is considered and reliability of its energy systems is modeled using Markov Chain and sequential Monte Carlo. In the proposed model, a method is presented for modeling failure rates in critical situations. The proposed model can be employed in planning studies to evaluate the adequacy of power supply system and using it, the appropriate capacity of each of the system components can be evaluated. Finally, simulation results of the proposed model on a test system are presented.

In this paper, a linear and differential attack to a chaotic image encryption scheme have been introduced and it has been shown that the intruder can obtain the plain image using these approximations with high probability. Also other weaknesses as inherent weakness of a chaotic map, improper use of map and weak keys have been presented. A complete alternative scheme has been suggested and simulated. The experimental results has shown the security and performance improvement of suggested scheme compared to the original and some other new schemes.

In the recent years, development in concrete technology results in production of ultrahigh performance fiber concrete. Having more than 150 MPa compressive strength and ductile behavior are two main characteristics of this concrete. Concrete structures experience different thermal conditions during their age and these conditions have direct influences on mechanical properties and durability of concrete. These effects can be natural atmospheric temperature difference or manmade conditions like fire. So investigation of temperature effects on concrete specially ultrahigh performance concrete which is expected to have high strength, is very important. In this research thermal characteristics of an ultrahigh performance concrete reinforced with steel fibers is investigated through calculating thermal expansion coefficient and resistance against high temperature. Thermal expansion coefficient of ultrahigh performance fiber concrete is higher than high performance concrete and normal concrete. In high temperature experiment, in wet specimens, by increasing the temperature to 400oC the strength of specimens decreased. In dry specimens, ultrahigh performance concrete is more sensitive to temperature increase than high performance concrete.