نشریه فناوری اطلاعات و ارتباطات انتظامی
پیاپی 6 (تابستان 1400)

Named data networks are a potential Internet architecture that is designed as a distributed network. Named data networks are very attractive for organizations that seek to share data on public networks and for which security of transmission and content is important. Therefore, this type of network can be implemented within the integrated police network if the defects and shortcomings are eliminated.Since data transfer using a data-driven network does not require an IP address, ordinary packets are not identifiable during the transfer process, and only the sender and receiver know which data needs to be retrieved. This will provide a new layer of security, such as encryption. Now, in this article, named data networks and the effect of distributed denial of service attacks on it are studied in order to find the main weakness of this network against these attacks. The proposed method changes the Nack and the link layer congestion detection protocol is added to the best known network path strategy. These changes have been made in order to use the network bandwidth more effectively and with the aim of making more use of these networks in case of congestion and denial of service attacks. The experiments performed after simulating the proposed method resulted in at least a 70% improvement in network access and a 40% improvement in network data recovery, and a 27% improvement in the need to retransmit the network in congestion compared to previous solutions.

Traffic congestion and route guidance are essential components of urban development in large cities. The vehicles routing and the movement of traffic have a direct impact on each other. Therefore, the first step is to set a benchmark for assessing the traffic situation. The type of vehicles must also be considered in the navigation. Emergency vehicles (fire, emergency, and police) must arrive at their mission site as soon as possible. Public transportation must also go according to plan. Vehicle drivers can choose a street as an intermediate destination (for example, for police cars dispatch, getting to the mission site, going to the destination can be considered). This article has tried to arrive at, the emergency vehicles on time, 1) routing by choosing an intermediate destination for vehicles, and 2) prioritizing vehicles. The first algorithm proposes an agent-based route guidance model that, in addition to finding routes with the shortest travel time, drivers can choose a part of the route as an intermediate destination according to their interests to increase their level of satisfaction. The second algorithm considers the presence of emergency vehicles including the police, so that they can arrive at their mission site sooner. The routing algorithm based on the ant colony with evaporating pheromone finds the shortest route with the shortest travel time. The simulation results prove that the proposed algorithms perform better and the arrival time of the emergency vehicles, including the police, has improved by 87.19%, which is a significant amount.

Detection of acetone gas is important to detect explosives produced from acetone in terrorist bombings, medical diagnostics and environmental protection against pollutants. In this study, using density-functional theory (DFT), the acetone sensing enhancement of carbon nanotubes decorated with zinc oxide nanowires (CNT/ZnO) was investigated. It was shown that the adsorption of acetone on pure carbon nanotubes (CNT) is done physically with an adsorption energy of -0.64 eV, but by decorating the nanotubes with zinc oxide nanowires (ZnO), the maximum adsorption energy of -2.43 eV is obtained at the connection level of the nanowire to the nanotube. It was also shown that by increasing the length of ZnO, the adsorption intensity depending on the adsorption location, increases at the contact point of ZnO to CNT and decreases at points far from contact surface, respectively. By examining the changes in the energy band diagram and density of states (DOS) of pure and decorated structures, it was observed that the adsorption of acetone does not cause much change in the bandgap or DOS of CNT, but the adsorption of this gas on CNT/ZnO is in a way that by shifting the DOS to lower energies, it changes the electronic nature of this nanostructure. The results showed that CNT decoration with ZnO, would have a special effect on improving its sensing performance in acetone gas detection. Using the introduced structure is preferable than other gas sensors due to its small size and room-temperature operation for defense applications such as smartening of security inspection systems.

Cloud computing technology is of particular importance in service businesses, especially security applications for the police, due to its role in reducing energy consumption, reducing capital costs, increasing security and integrated access to information from other intelligent systems. As such, the current study set out to identify the components which impact cloud computing technology in providing intelligent services in the rail transportation system. Using Delphi technique, this cross-sectional and descriptive-analytical study was conducted in 1399. The panel of experts in this study included eight managers in Tehran Urban and Suburban Metro Company. The Delphi study was conducted in three rounds. Validity was assessed using CVI and CVR, while the reliability was assessed using Cronbach's alpha. During the study, 33 components were proposed by the research team and via a comprehensive literature review. In addition, 10 components were suggested by the panel of experts. The results of the study showed that 23 components were selected in the form of four dimensions of access, strategy, security and services as the most important components affecting cloud computing technology in providing intelligent services in the selected rail transportation system. In other words, the most important challenge related to the service and infrastructure sectors, but strategically there were fewer challenges. The results can be useful for decision makers in the field of security policy-making and the maintenance of security in the community (authentication and keeping privacy) by the police.

Distributed Denial of Service (DDoS) attack is an attempt to make network resources inaccessible to legitimate users. Today, the number of DDoS attacks is increasing rapidly, this is a threat to Internet users, and police networks are no exception to this threat and are more sensitive due to the constant need for these networks to respond to legal requests. Although the target of DDoS attacks may be different, they generally try to temporarily or permanently disable the services of a victim server connected to the Internet. In this paper, a network layer-based method independent from communication protocols is presented that is able to detect attack behaviors without the need to know normal network behaviors. In addition, this method does not need to store large volumes of profiles, multiple lists and attack signatures. This method is done in three steps: feature extraction through a two-dimensional wavelet decomposition that provides the energy distribution diagram, detection of the change point with the help of fuzzy logic rules and deep neural network analysis as the final step of detection. The proposed method was investigated on VAST and ISCX datasets in which it was able to detect DDoS attacks in 10-second periods with 99.99% accuracy for VAST dataset and 99.08% accuracy for ISCX dataset.

Currently, different types of crimes have occurred in the country's geographical area. As a leading organization at any given moment, the police have produced data that will need to be processed quickly and analyzed to be used in missions. This requires an intelligent mechanism that cannot be exploited without the use of machine capacities. Increasing hardware and software equipment in an organization will lead to energy consumption. With a view to a clean, wireless, and cordless environment and permanent connection of systems and their stability, wireless power transfer (WPT)technology is the best option for wirelessly charging of electronic equipment. All missions, hardware are charged wirelessly, and system outages do not disrupt operations. To make the police intelligent, all kinds of electronic equipment available at the border, corridor, and police station, etc., can be equipped with wireless power transmission technology, eliminating cables and the ability to charge remotely. The research has been applied in terms of purpose and by simulation method. Since the transmitter efficiency depends on the precise design of the amplifier section, in this paper, the Class E power amplifier is designed at a frequency of 145 MHz. It is obtained in the ADS simulation software, and the efficiency is 2.77. The analysis shows that this technology can be used in places And various police missions charged the equipment permanently.

This paper describes the design of 6W C-band power amplifier based on the GaN-technology for use in TT&C-transmitters. Simple design, relatively high efficiency are the main features of this design. The operational frequency range spanned from 3.4GHz to 4.25GHz. It was decided to design the amplifier with the 6W CGH4006P transistor, from Cree. In the design procedure, source and load pull simulations were performed in order to retrieve the optimal impedances for the transistor and as a basis for the design of the matching networks. The amplifier design was done using a large signal model from Cree in Advanced Design System. The simulated results showed that the design were capable of delivering 6W output power throughout the frequency band. P1dB is 39dBm in EM simulation. For this Amplifier the transducer gain is 11-13dBm. The power amplifier obtained a simulated power added efficiency (PAE) 54-60% at 39dBm output power. PA obtained a small signal gain above 13dB.