In recent years, GPS has attracted the attention of many users in the industrial, military and commercial fields due to its accurate time and position information. Because the received signal power on the earth surface is lower than the thermal noise level, it can seriously subject to intentional or unintentional Interferences. Intentional Interference is known as ‘jamming’. Although the GPS spread-spectrum signal structure has some inherent jam protection, when a hostile jammer want to disturb a GPS system need only send out a jamming signal with enough power and suitable time/frequency properties to deny the use of GPS. Using Neural Networks (NNs) is a non-linear filtering approach for tracking and canceling Interference. In this paper, we investigate one of the NNs structures (multi-layer perceptron) and the possibility of Interference elimination using this network. Finally, the proposed method will be compared with one of wavelet structures. It can be seen that the proposed algorithm identifies more than four satellites for solving the navigation equations. In addition, it is robust against the increment of jammer power ( from 25dB to 50dB) and improves the similarity of predicted signal to the real one about 45% in comparison with the wavelet structure.

One of the destructive factors in communication and radar systems is intentional Interference which is created by using jammers to disrupt the enemy's systems. If the intentional Interference is not reduced well, the efficiency of the communication system would be completely disrupted. Jammers purposefully interfere and affect the optimal performance of the system. The NLMS adaptive algorithm is one of effective algorithms in eliminating intentional Interference. In this paper, a new algorithm for eliminating intentional Interference in cognitive radio systems using wavelet transform is presented. In the simulations, a 25-user cognitive radio system is used as a victim network in the vicinity of a network of primary users with Markov channel functionality. Considering eleven different scenarios, the performance of the proposed algorithm is investigated. To evaluate the performance of the proposed algorithm, the criterion of successful transmission of information in terms of signal to jammer ratio in each of the scenarios is discussed. According to the simulation results, the proposed algorithm, compared to the adaptive algorithm (NLMS), shows a significant improvement. The results, show 13% improvement for the proposed algorithm in successful transmission at SJR=5dB compared to the NLMS adaptive algorithm.

These days, an increase in terrorist attacks and advanced techniques for creating small explosive devices using powerful, high-explosive materials are causing massive building collapses, economic losses, and death. Protecting and mitigating the effects of explosions on structures and the people in them have become important to scientists. In this article, the effect of different parameters on the target structure, such as standoff distance, charge weight, and the use of protection systems have been reviewed. It is not economical to design the main parts of the structure so that they can withstand different hazards, therefore the use of different protection systems and materials such as walls, fences, sacrificial claddings, sandwich panels, and FRP, to mitigate the blast pressure and diffracted waves, and the results of their analysis have been discussed. The role of these protection systems is to absorb high kinetic energy in the form of strain energy through deformation. It is sometimes possible to replace these systems with a new one after failure at a lower cost than structures without a protection system. This paper presents an overview for beginner researchers to study the effects of the explosion on the structures and investigate solutions to reduce these harmful effects and protect the structures, and their inhabitants.

Different methods exist for jamming Mitigation and we should choose a method based the jammer type and other parameters. One of the jammers is narrow band FM jammer and we use subspace projection techniques for the suppression of this type of jammer. In subspace projection technique, we estimate the IF of signals and construct the subspace vector that is orthogonal to jammer vector by increasing the number of antennas in the array; we enhance the performance of system. The subspace projection method was simulated in MATLAB and the receiver output SINR in several conditions was calculated. In the case of IF estimation error, the SINR of the system is reduced; in this condition the use of an antenna array will increase the performance of the system compared to a single antenna.    

The aim of this study was to use meta-analysis to identify the enteric methane (CH4) Mitigation strategy that reduced CH4 emission without lowering production. To this end, a database initially developed was updated, compiling data from 61 publications (233 experiments) for various observations in dairy cattle on effects of hydrogen sink (H-sink), ionophore, lipid and concentrate feeds inclusion on enteric CH4 produc-tion, milk production and milk composition from dair cattle. There was no significant effect (P>0. 05) of H-sink and ionophore feeds inclusion on CHy4 production while supplementation of lipid and concentrate considerably suppressed CH4 production (P<0. 05). CH4 production per kg milk produced was not de-pressed with H-sink treatment (P<0. 05). Lipids lightly increased CH4 production per kg milk from 26. 19 g kg− 1 for control to 29. 12 g kg− 1 for treatment (P>0. 05), while concentrate and ionophore feeds inclusion decreased CH4 production per kg milk with no significant effect (P>0. 05). There was a significant effect of concentrate on milk protein and milk yield, which increased from 23. 27 kg d− 1 for control to 26. 52 kg d− 1 for concentrate treated diet (P<0. 05). Milk yield and milk protein was not significantly affected with H-sink, ionophore and lipid feeds inclusion (P>0. 05). This meta-analysis demonstrates that lipid and concen-trate feeds inclusion reduced CH4 emissions from dairy cattle without lowering their production.

The plaintiff is under a duty to mitigate the losses resulting from the defendant's negligence; so that he will not be able to .claim for losses which could have by the taking reasonable steps to reduce those losses, once the has been treated. This duty is justified by the principle of causation. The plaintiff may claim compensation only for the losses caused by the defendant's wrongful act. This rule is a rule of common law but its effects are accepted in other legal systems, such as Islamic and Iranian law. It follows from this rule that: 1- If the plaintiff fails to take reasonable steps to minimize his loss, he can not recover any thing in respect of the extra losses. 2- The plaintiff may be able to recover amounts paid in, reasonable steps to mitigate losses.