مجله علوم و فناوری های پدافند نوین
سال دوازدهم شماره 1 (پیاپی 43، بهار 1400)

In the field of cyber defense, researchers always suffer from the lack of a proper dataset to evaluate their proposed theories and methods. Unfortunately, in the various datasets existing in cyber defense scope, the ground truth is ambiguous, and the scenarios used by the attackers to carry out the attacks are unclear. This will lead to a serious challenge to the verification of methods and researches in this area. In this paper, a method is proposed by which a new database can be generated with the explisit ground truth and predetermined scenarios for multistage cyber attacks. In this method, a cyber attack guidance template is used to determine the various stages of the attacks and an attack scenario generator is also used to determine the scenarios used by simulated attackers. Network topology is considered as input, and random variables are used to create variety in simulator performances. Also, in the proposed method, various techniques such as fuzzy c-means for clustering, and artificial neural networks for classification are used. To set the simulator parameters, the CDX dataset is used and its ability to create a new dataset of multistage cyber attacks is well illustrated. To evaluate the proposed method, scoring by SME's is used, and finally with the mean score of 90.7, it had been approved.

An aircraft defense dierential game is analyzed where a Target aircraft and a Defender missile team up to defeat an Attacker missile. Attacker pursues the (slower) Target which evades Attacker with the help of Defender, which is endowed with a non-zero capture radius. Target and Defender cooperate in a way that Defender intercepts Attacker before the latter reaches Target. The payoff functional is the distance between Target and Attacker at the interception time which Attacker strives to minimize and Target/Defender team strives to maximize. The work in this paper generalizes existing results to consider restrictions on aircraft.

The study of low power wireless radio systems is an area in modern defense that especially deals with higher performance filters. In recent years, Gm-C filters have drawn attention due to their high frequency performance and integrability. In this paper, a fourth-order low-pass Gm-C filter with on-chip automatic tuning circuit is presented. The core of this filter is a low-voltage high-frequency CMOS inverter-based operational transconductance amplifier (OTA). To improve the linearity of the OTA, a new common-mode feedback (CMFB) circuit is presented that is combined with a common-mode feedforward (CMFF) circuit. Moreover, a new automatic tuning circuit is presented. By tuning the bulk voltage of transistors, this circuit compensates the effects of mismatches and temperature changes on the OTA, and therefore, on the filter cutoff frequency. Furthermore, this circuit consumes small portion of the power consumed by the filter. The circuits are designed and simulated in Cadence using TSMC 90nm CMOS technology and a 1 V power supply. The post-layout simulation results show that the DC differential gain, common-mode gain, -3 dB cutoff frequency and unity-gain frequency of the OTA are 34.7 dB, -26 dB, 255 MHz and 13.8 GHz, respectively. The cutoff frequency of the filter is 1 GHz, and by applying 0.2 Vp-p input voltages, the third-order intermodulation (IM3) of the filter at the cutoff frequency is -38 dB. The power consumption and the area of the filter are 4.8 mW and 0.043 × 0.038 mm2, respectively. Moreover, Monte Carlo simulations show the good robustness of proposed filter against the process errors.

Cognitive radio is well known as an ultra-wideband communication system that intelligently optimizes the available frequency spectrum by implementing the dynamic spectrum monitoring method. This system can meet the needs of field communication systems well and be used in most operational equipment. In this paper, to realize this system, using the cross coupling of two active inductors consisting of common gate topology and feedback, in a differential structure, a novel ultra-wideband low noise amplifier is designed. The use of active inductor, in addition to increasing the amplifier bandwidth and reducing the chip area, due to its high quality factor, it also has the ability to adjust the inductance and frequency. In addition to input matching in the entire frequency bandwidth, this structure increases the transconductance of the transistors with the proposed structure and reduces the power consumption and the noise figure of the circuit. The simulation results show that in the frequency range of 50 MHz to 10 GHz, this structure has a better input matching than -10 dB, power gain of 10.4 dB, noise figure variations of 3-6.7 dB and a third-order intercept point is -4 dBm. The proposed LNA consumes 9.29 mW from a 1.8 V power supply.

The fuel cell, as an efficient and environmentally friendly energy source, has received much attention in recent years. In this paper, a comprehensive model of the 6-kW proton exchange membrane (PEM) fuel cell, including dynamic model along with the electrical model, is presented. The mass balance and thermodynamic energy balance, temperature dynamics, open-circuit output voltage, voltage losses, and the formation of charge double layer in the PEM fuel cell are modeled. The connection of fuel cells to the microgrids in applications such as distributed power generation, power systems of naval defense systems, and military ships requires DC-DC power converters with high voltage gain, high capability of power processing, and high levels of current absorbed from the dc source. In this context, this paper proposes the use of an interleaved boost DC-DC converter and an interleaved boost with voltage multiplier converter (IBVM) to connect the fuel cell to the microgrids. Then a model predictive control algorithm is proposed for the two proposed converter as a current-mode controller to control the injected current by fuel cell as well as to smooth output fluctuations of the fuel cell. Compared with traditional cascade linear control, the proposed scheme avoids PID parameters tuning, PWM modulation, and coordinate transformation. The simulation results are given to confirm the effectiveness of the proposed control method, the chosen converters, and the obtained model of PEM fuel cell.

Adaptive steganography methods use variable embedding capacity according to the uniformity or edges of image areas. ALSBMR is an adaptive method with two main stages: Selecting suitable pixels, and embedding them using the LSBMR method. This method utilizes two adaptive keys between the sender and the receiver to determine the block rotation angle and select the embedding path. In the original method, the keys are randomly selected by the sender with no specific criteria and then sent to the receiver. The proposed method models key selection as an optimization problem and uses Genetic Algorithm (GA) and Teaching-Learning-Based Optimization (TLBO) to find the optimal keys. Two fitness functions are used to further evaluate the difference as well as the histogram difference between the cover and stego images. The results show that the image embedded with the proposed method has improved quality and security compared to the base method. Since all steganography methods require embedding keys, intelligent key selection can improve the performance of existing steganography methods.

From a passive defense perspective, renewable sources are strategic resources and can be a good alternative to conventional power plants in the event of war or sanctions. In this paper, the capability of solarpower plant to improve the inter area oscillations damping in the power grid is investigated. Due to the significant increase in solar power plants with high penetration levels in the power system, the participation of these resources in order to increase the damping of power system inter area oscillations seems to be important. Accordingly, the purpose of this paper is to use the Synchronverter control model to improve the inter area oscillations damping and also to increase the inertia of the power system in the presence of a solar power plant. To perform the simulations in this paper, the solar power plant with its controllers in the DSL environment of DIgSILENT PowerFactory software is precisely modeled. In order to show the capability of the synchronverter control model to improve the damping of inter area oscillations, Kundur power system as well as the transmission network of Zanjan Regional Electricity Company have been used to perform simulations in the time domain. The results of the simulations performed in the conditions of occurrence of various disturbances (change of torque, sudden increase of load and short circuit fault), show the proper performance of the proposed method.

In this paper, we propose a method to localize an active aerial target (emitter) in three dimensions using the time difference and the frequency difference of the received signal from the target and the reflected signals from two large auxiliary terrestrial targets (pseudo stations) with known positions in a fixed ground-based station. Due to the pseudo and the main stations' terrestrial nature, it is not possible to obtain the altitude of the target in the traditional methods, so that these methods solve the localization problems in two dimensions and do not consider the altitude of the target. In this paper, a method is proposed to achieve the target altitude with acceptable accuracy to address this issue. The capability to give the target altitude and at the same time have low computational complexity makes this method an attractive option to be considered in practical applications. In methods where the variables of location and target velocity in the equations are solved implicitly and interdependently, the volume of calculations to achieve the desired accuracy in the text of the article is 250 times. Of course, this method does not converge for low signal-to-noise ratios.

Nowadays, unique identifiers are used to authenticate individuals. These identifiers are called biometrics with iris being one of the most popular ones. Research performed in this paper consist of designing a new identification system based on improved security in iris database. In this paper, we propose an iris template protection method based on Visual Cryptography (VC) and RSA. For iris template protection, the binary iris template is divided into two shares using VC, where one share is stored in the database and the other is kept with the user on a smart    card. In order to provide additional security, the share that is stored in the database is encrypted with RSA encryption. In the next step the patterns obtained from each image are compared with the patterns in the database and, by defining a threshold, the identification procedure is carried out. In this paper, the CASIA - v1 image bank has been used. The EER value after encryption is approximately 0.01. We then expose the system to different noises such as salt and pepper, white Gaussian noise and mean filt.r. After applying the noises, we haveit is observed that the system has shows been better performance compared to the than other systems which we have investigated.

In this research, doped and undoped BaMgAl10O17 nanoparticles were synthsized using a new simple combustion synthetic method. A hybrid fuel consisting of urea and glycine was utilized in absence of reductive atmosphe .The morphology, structure, purity of sample phases and the features of nanoparticles light-glowing were investigared using field emission scanning electron microscope (FE-SEM), X-Ray Diffraction (XRD) pattern, and Photoluminescence (PL). The effect of urea fuel was studied either solely or mixed with glycine for the dopant reduction. The results of morphology and X-ray diffraction imply narrow-bar-structured rice with an approximated dimension of 45 - 65 nm with roughly high purity. In the synthesized doped europium with urea hybrid fuel and glycine, the photoluminescence emission spectrum is observed within the wavelengthrange of 400-500 nm centered at 447 nm. The scintillation responses of the samples to the 90Sr beta and 241Am gamma radiation sources and the ,discrimination capability of beta and gamma emissions in the 90Sr/90Y sources are investigated. The results showed that the activated nanoparticles having doped Eu2+ have a good sensitivity to bate particles and. can be an appropriated alternative for detection applications of beta particles in the spaces combined with gamma photons and beta particles.