Advanced Defense Science and Technology
Year:2014 | Volume:4 | Issue:4 |Papers Count:11

Active imagery technologies such as SAR systems, have significant capabilities comparing with passive imagery technologies such as electro-optical systems. The capabilities of these imaging systems, enable them to acquire and obtain information that are not accessible in the other methods. On the other side, these information are very important for military forces. Hence, some passive defence activities such as camouflage, concealment and deception (CCD) are necessary to secure information against these types of imagery systems. This paper evaluates the capability of the reflectors as countermeasures against SAR imaging system based on their operational model. The reflectors are capable to produce very large radar cross section (RCS) as compared to their size; therefore, they can be used as false targets. According to operational model of SAR imaging systems, these false targets appear in SAR images and they cause disruption in acquiring data by SAR systems. This paper presents different plans for camouflage of targets and deception of SAR imaging systems by use of reflectors. A real SAR data of RADARSAT-1 from the North of Iran is used for simulation. The results show the efficiency and effectiveness of the proposed plans for countermeasure against the SAR imagery systems.

Diesel engines are used in sensitive military and industrial applications as stationary power sources. In order to stabilize voltage and frequency of connected generator, diesel engine RPM would be controlled accurately. In most cases mechanical methods are used to fix the engine RPM but this method is not very accurate. In this paper a new electronic governor has been designed and constructed with programmable logic controllers (PLC). The designed controller is cheaper, more flexible and more accurate than mechanical governor. It has initially been simulated in MATLAB Simulink which showed adequate results. It was then constructed and installed on a 350 KW diesel generator in which 3. 2% improvement over conventional methods was observed.

Phasor Measurement Units (PMUs) have made possible the set up of Wide-Area Monitoring, Protection, and Control (WAMPAC) systems as the energy management infrastructure under critical situations in the modern electrical market. In this paper, a new optimal PMU placement using Mixed-Integer Linear Programming (MILP), which improves the power system observability besides minimizing the PMUs installation cost, is proposed. Also, a systematic method is introduced in order to apply the effect of zero injection buses and power flow measurements as two vogue conventional measurements. The effect of branch outage and PMU loss as effective contingencies on system observability is studied in the absence and presence of conventional measurements. The proposed method is examined on three known IEEE test systems and Azarbayjan 40-bus system. The results have shown that the method improves the power system observability.

Unique features of active sonar and the possibility of easy transmission of acoustic signals in underwater environment provide the ability to identify and track the underwater targets. Use of sonar for diver detection in order to prevent the diver’ s entrance to harbor equipment plants, protection from the coastal power and etc are the applications of acoustic signals in passive defence. Diver detection could be done by getting help from the active sonar, making an appropriate mathematical model for the diver and measuring its target strength. In diver detection by active method, its target strength is the most important factor. In this paper, target strength of body components and air cylinder have been measured using Urick cylindrical model and considering the swimming state of the diver, the results have been assembled to obtaining the returning echo from the whole body. The results have also been simulated by MATLAB software to detect the diver.

A simple method has been developed for immobilization of acetylcholinesterase (AChE) covalent bonding to a multiwall carbon nanotube (MWNT) modified glassy carbon electrode and a sensitive biosensor for rapid determination of triethylethiophosphate (nerve agent (VX) simulant) is proposed. MWNT improved the interface enzymatic hydrolysis reaction and increased the voltammetric response of the sensor. Under optimum conditions, the inhibition of triethylethiophosphate on AChE increased linearly to triethylethiophosphate in the 0. 13 to 0. 44 nM concentration range. The detection limit was 0. 093 nM taken as the concentration equivalent to 10% of inhibition. The reproducibility of the biosensors obtained under optimum condition was good: RSD of 3% was observed for five replicates using the same biosensor. The sensor was found to be stable for over 2 months.

In this paper, the immobilization and hybridization of single strand DNA (ssDNA) sequences of rfbE gene Escherichia coli O157: H7 has been studied by electrochemical impedance spectroscopy technique. A self-assembled monolayer of the ssDNA was immobilized on the gold electrode for three hours at ambient temperature (25 ° C). A mixed monolayer comprising both mercaptohexanol (MCH) and mercaptopropionic acid (MPA) were used as an interface design for developing biosensor. The hybridization of DNA/DNA was performed by immersion the modified gold electrode with ssDNA at a concentration of target DNA, 1 μ M in the phosphate buffer solution (pH 7. 4). Cyclic voltammetry and electrochemical impedance spectroscopy techniques were used for investigation of the DNA immobilization and hybridization. Results showed that immobilization and hybridization of DNA on gold electrode is suitable. This research underlie the future development of nanobiosensor electrochemical for detection of biological agents.

A successful attack against vital maritime infrastructures has the potential to cause major economic disruption and create mass casualties and conflagration at national levels. Taking into considerations the vital importance of the seaports, the vulnerable points in the seaports must be recognized and necessary steps should be implemented in order to prevent potential adversary’ s attacks. Therefore, a coordinated pattern is provided in this investigation to identify the vulnerabilities and provide security of the ports, through the identification of the assets and the ongoing threats based on passive defence considerations. In this article, attempts have been made to introduce a critical infrastructures’ vulnerability assessment method which is the product of combined local and current methods such as RAMCAP. This method is based on risk assessment as a function of threat, vulnerability and effects where assets, threats and vulnerabilities are estimated and security measures are implemented. Therefore, Fuzzy method is used to model the vulnerability assessment and the results are presented through MATLAB software.

Wireless sensor networks afford the possibility to control remote monitoring of many environments (such as military ones) by hundreds of tiny sensor nodes. Restriction of energy consumption is a major challenge in these networks, which will affect the lifetime of the network. One of the key solutions to solving the challenge is data aggregation and avoiding of repeated data sending. The most popular communication protocols are clustering and tree based data aggregation. Clustering in data aggregation issue leads to energy balance, but energy consumption is high due to long distances between cluster heads and base station. In the tree structure, due to short distances between nodes, energy consumption is low but, the depth of the tree is usually high. In this paper, a hybrid analytical hierarchical process named CTDA is proposed in which energy consumption is reduced by clustering and minimum spanning tree for data aggregation in wireless sensor networks. The simulation of the proposed method illustrates reduction in energy consumption compared to two aformentioned protocols.