مجله علوم و فناوری های پدافند نوین
سال پنجم شماره 3 (پیاپی 17، پاییز 1393)

The benefits of renewable energy have led to the increased penetration of Distributed Generators (DG) not only in the military sites، but have also increased the availability of continuous supply of electrical energy even in the critical conditions. During the national grid supply interruption، the stability of these systems (micro grid) is essential. In order to maintain frequency stability of these isolated micro grids، a balance between generation and consumption has to be always maintained. It is customary to use energy saving devices to maintain balance by increasing generation in the short runs، where large frequency deviation results in load shedding. In this paper use of interruptible/curtailable loads to maintain the balance is proposed. That is a specific load has been reduced to control the frequency. Simulation of the proposed method has been run on the model of a real network which has verified the results and its effectiveness.

Aerial photogrammetry using metric cameras is a common method for generating an ortho-photo. But use of this technique is not occasionally possible due to some problems like high cost and human casualties. An alternative approach is using nonmetric cameras mounted on unmanned aerial vehicles. In this research، to evaluate this approach، a practical case study in the industrial complex of Neka is conducted for generating a large scale ortho-photo by using a non-automatic Quadrotor and a 10 mega-pixel sony-HX5V camera. The experimental results show that the mentioned approach has an ability to generate ortho-photos in scales from 1:500 to 1:100 as well as contours with 15 cm intervals. Moreover، the results show that this approach is superior to the conventional aerial photogrammetry in areas of several hundred acres in terms of cost and time.

In this paper، the electrochemical oxidation of catechol was studied in the presence of thiopental in phosphate buffer solution (0. 2 mol L-1، pH=6. 0) at the surface of glassy carbon electrode (GC) by cyclic voltammetry technique. The results showed that cathodic peak current of catechol reduced in the presence of various concentrations of thiopental and catechol can participate in a 1،4-Michael addition reaction with thiopental under an electrochemical – chemical (EC) mechanism. Then، the differential pulse voltammetry technique is used for determination of thiopental. The decreasing of the cathodic current of catechol showed a linear relationship with the thiopental concentration in the range of 5. 0×10-6- 125. 0×10-6mol L-1 and a detection limit of 2. 0×10-6mol L-1. The method was successfully applied for determination of thiopental in human serum samples.

This article study and compare malware families and malware detection methods and propose a new and efficient method for malware detection by static analysis. Proposed method based on PE Structure of executable files. Our method propose some new feathers such as quantity، name and size of sections، name of system calls and their libraries in IAT and EAT table، entry point and entropy for detection and distinguishes malwares and benign files by observing and exploring PE structure and header of mentioned files very deeply. These feathers can assign positive and negative point to determine malignant or benign rate of an unknown executable file by formulas of proposed method. We extract these features by doing data-mining on a large scale consist near 15000 malwares and 13500 benign files and used machine learning techniques for train and learn an intelligent rule base model for malware detection. Proposed method of this article cluster malwares in 5 and benign files in 2 families. This article evaluate accuracy of proposed method in detection and clustering malware and benign files and indicate that proposed method can detect and cluster malwares by more than 95 percent in accuracy and compete with other methods and get second ranked.

In many years Breaking of cryptography Algorithms have been taken into consideration as a challenge. Data Encryption Standard (DES) is used as a standard to keep the information confidential and allows the research studies to investigate it. S-DES is the simplified version of Data Encryption Standard Algorithm which is used by the researchers for investigation. The present study uses SPSO algorithm to break SDES algorithm. To break SDES algorithm the SPSO was optimized. There were some attacks on some blocks of the cipher text and the obtained results revealed that this algorithm had a better performance in detecting main key bits in shortest time so that، in detection factor main key bits، ten main key bits have been discovered and in the time of detection factor main key bits، time over a minute to less than twenty seconds dropped in comparison with Previous work.

Using Electromagnetic waves shields is the method in Passive Defense that helps to reduce damages caused by modern Electromagnetic threats such as EMP and HMP. The Substances which used in shields structure should have special characteristics like relevant electrical and magnetic conductivity coefficients. This Research is related to construction of special concrete which has high electrical conductivity for reduction and elimination of high power electromagnetic waves threats as electromagnetic shields in any kinds of critical and infrastructural establishments. In this paper firstly we compared the reflection of X-band wave on the pieces of the pure concrete with its reflection on concrete block 5*5*5 Cm mixed by 5 percent carbon black. In another experiment، the effect of concrete thickness on transmittance and wave attenuation was measured and finally، in another experiment، the effect of carbon black mixed concrete was investigated. The best wave absorption resulted at the 2 Cm thickness and 10% carbon black equal to 19. 35 -dB.

Power grid is mostly vulnerable to trained terrorists. The grid might go into instability or even blackout when exposed to terrorism attacks. One of the most significant attacks is impinging upon substations in the power grid. The purpose of this paper is to reduce congestion of grid lines when a substation is eliminated from the system. To simulate such attacks، the substations in the system are removed one by one to determine the substation whose elimination would cause the highest grid congestion. The next step is congestion management by TCSC which is one of the FACTS elements. CFA-PSO and ABC algorithms are used to locate the TCSC in optimal place. To evaluate the capability of the proposed method، it is applied to IEEE 14 bus standard system and the results are analyzed. Simulation results show that congestion decreases when substation is eliminated.