نشریه فناوری اطلاعات و ارتباطات انتظامی
پیاپی 12 (زمستان 1401)

Background and purpose: 

Since 2007, with the introduction of Bitcoin based on blockchain technology, a new generation of electronic money has emerged that can circulate among different people and be used in the cycle of economic exchanges. Decentralization, cross-border nature, anonymity of users, anonymity and complexity of processes of interception and identification of participants, encryption and irreversibility of transactions are the features that draw the attention of criminals to the use of cryptocurrencies in criminal activities. The purpose of this research is to describe and explain the crimes related to the field of cryptocurrencies and to identify the legal challenges of these crimes.

The current research is applied in terms of its purpose, and in terms of research tools, it is documentary and library, and the information collected using library resources that have been analyzed by descriptive-analytical method.

The result of this research shows that ambiguity in the nature of cryptocurrencies, how to apply laws and regulations on cryptocurrencies, how to identify and detect crimes, seizure and confiscation and storage of cryptocurrencies, use of electronic evidence and determination of jurisdiction are some of the challenges. The main issue in the proceedings of crimes related to cryptocurrencies that judicial and police authorities should pay attention to and provide basic solutions in this regard.

With the increasing spread of attacks on computer networks, the use of intrusion detection systems is inevitable. The purpose of an intrusion detection system is to monitor abnormal activities and to distinguish between normal and abnormal behaviors (intrusion) in a host system or in a network. One of the main problems of intrusion detection systems is the high volume of alarms, which practically eliminates the possibility of dealing with them. An intrusion detection system is effective that can detect a wide range of attacks while reducing the amount of false alarms. In this paper, a new feature-based intrusion detection approach is proposed in which the AdaBoost algorithm combines with the Harris Hawks optimization algorithm and optimized parameters. Studies show that the proposed method detects malicious samples in computer networks with an average accuracy in the CICIDS2017 dataset is 99.86% and for the NSL_KDD dataset is 99.88%; comparing the findings with similar works also indicates that the proposed method is more accurate than them in distinguishing invasive samples from normal.

Recently, data has become a valuable asset in organizations, and data governance has become one of the priorities of organizations. The review of previous studies shows that the evaluation of the establishment of data governance in organizations is carried out qualitatively, and organizations cannot implement their organizational data governance architecture and model based on a written and specific plan. The purpose of this research is to provide a quantitative method to measure the level of data governance in an organization and subsequently plan to improve the existing situation. Due to the qualitative nature of influencing factors in measuring the level of establishment, fuzzy concepts have been used for modeling and analysis. This survey was conducted using a questionnaire tool among 13 experts in the field of information technology and people familiar with this field, using the fuzzy Delphi method, in which the triangular fuzzy number (L, M, U) was used in this research, and the experts gave their opinions. In the form of fuzzy variables, expression and evaluation were carried out in two stages, and the average of the first stage was equal to 0.15.49 and the second stage was equal to 0.15.52, with a difference of 0.03%, and the results show that there is a significant and positive relationship between the components and The indicators of the establishment of data governance are, at the end, a technical model is presented based on this for the establishment of police organizational data governance

Today, moving prohibited objects is one of the security threats in high-traffic places like airports, and it is essential to have an efficient system to deal with them. Current systems, which often focus on metal detection, may not only consider unsuspicious items such as coins as threats but also fail to detect new explosives that are not metal-based. A passive millimeter wave (PMMW) imaging system is an image formation method through the passive detection of energy naturally emitted from an object in the millimeter wave range. This system generates images of concealed objects in the human body by measuring the radiometric temperature emitted from the front scene in the millimeter wave band as a safe security tool. The image produced by this system is noisy and has low resolution, and it is not possible to show all its details compared to the visible image. In this paper, a method is presented for noise reduction in PMMW images and better detection of hidden targets compared to the background of the human body. In this method, first, the noise is detected then an adaptive median filter is proposed to remove the low-density salt-and-pepper noise. Next, another proposed algorithm based on the Shearlet transform is presented to reduce the Gaussian noise in the high-frequency components of the image. The implementation results show that the proposed algorithm efficiency is up to 6% better than the latest methods used for noise reduction and improve the resolution of real images received from a PMMW system.

In recent years, convolutional networks have achieved impressive results in the field of machine vision. Their high accuracy has led to their use in security and military fields, such as crime prediction and prevention. However, due to the huge calculations required by these networks, they cannot be used in embedded systems with limited computing resources. One solution to this problem is network pruning. In this method, a portion of the network is pruned while maintaining the initial structure to reduce calculations and enable use in embedded systems. Traditional pruning methods typically require manual determination of the criteria and amount of pruning, and they tend to perform well on specific networks. Automatic methods, on the other hand, do not have these disadvantages. However, they must address issues such as relaxing the search space, eliminating overfit during the training process, and addressing differences resulting from relaxing the search space.This article introduces a method based on gradient decent for network pruning. The method automatically searches for the optimal pruned network and can be easily applied to networks with skip connections. To compensate for lost accuracy, dynamic skip connections are used without increasing computation. Tests on valid datasets demonstrate that this method achieves a better balance between accuracy and network pruning than previous methods.

electronic equipment needs electrical energy to operate, and in the near future, efforts will be made to supply the electric current related to the sensors located in the remote command and control scene. In this regard, wireless power transmission (WPT) systems are the most important circuits for power transmission and charging of sensors and equipment deployed in the operation scene related to command and control. In the design of wireless power transmission systems, power amplifiers are of special importance. In this regard, in this paper, a EF class power amplifier is introduced. The proposed amplifier is based on the design of the class E power amplifier, with the difference that a resonator circuit has been added to it. This resonator circuit, which consists of an inductor and a series capacitor, cuts the voltage peak in the transistor by resonating in high-order harmonics. And as a result, it reduces the stress and pressure on the transistor to produce high powers. As a result, the output power of the amplifier increases and the high supply voltage does not put the transistor under stress. In order to evaluate the proposed amplifier performance, a wireless power transmission system is simulated and analyzed. The output power of the amplifier is 6.232 watts, with a high efficiency of 95.5%. For the designed wireless power transmission system, the transmission power efficiency is 73.1% in the case where there is the smallest distance between the coils. The results of the proposed plan are superior to the previous works.

One of the methods for optimizing the radiation characteristics of microstrip antennas is using metamaterial as substrate and superstrate. In this research, a rectangular microstrip antenna with circular polarization and conical pattern is designed at 2.2 GHz frequency. For creating circular polarization cutting corner method is used and to create conical pattern, 4 array rectangular microstrip patch antennas are used and each antenna is feeded by microstrip line and whole of structure is feeded by a 50 Ω SMA connector. To improve the radiation characteristics and optimize the dimensions of antenna, a 10×10 aray layer of metamaterial is used as substrate and Then the antenna has been made. The metamaterial parameters such as Permeability (µ) and Permittivity (ε) is extracted by Nicolson-Rose method. The simulation results show that the antenna dimensions is decreased 30% and bandwidth and gain of the antenna are increased 17% and 45% respectively. All the simulation process for antenna designation is implemented in HFSS 18.2 software.

Microstrip antennas are of great importance and application in commercial, military and security sectors. These antennas have an important role due to the ability to cover multiple frequency bands in police communication systems, planned and tactical communications.In this paper, a miniature microstrip antenna is presented for application in several frequency bands and improving bandwidth. Antennas designed to cover different frequency bands should have small dimensions, all-directional radiation pattern and appropriate gain. In the proposed antenna, down sizing is provided through the metametric transmission line and its nourage is provided by electromagnetic coupling system. The designed antenna is a CRLH element. The Right- Hand part is composed of a 35 - micron copper metal patch with fractal and the left part is composed of an effective homogeneous transmission line, series capacitors and parallel inductor. Antenna on FR-4 substrate is characterized by impedance of 50 ohms and frequency range of 2 to 7 GHz and is very useful in radio frequency detection, microwave, DF and PF antennas. ADS software (2022.1.2), HFSS (15.3) to cover frequency bandwidth and miniature use of a fractal compound including frequency repetition of Koch kernel the same modified snowflake and in order to eliminate the disruption in the design of the system of polarization Symmetric and improved antenna bandwidth quality has been done through the idea of splitting ground. The proposed antenna provides a compact fractal microstrip antenna that improves resonance frequency, increased gain, and suitable impedance bandwidth.

Considering the topic of research in information technology and digital transformation, the present research was conducted with the aim of identifying and prioritizing the factors affecting the implementation of digital transformation in a Technology-based organization. This research is applied and developmental in terms of purpose and exploratory and survey method in terms of type. The statistical population of the research is people with at least 15 years of work experience in a Technology-based organization with at least a master's degree in related fields, and the sampling was done in a non-random way until it reached the saturation point, in the experts' section. Field method and interview tools were used to extract effective factors on the implementation of digital transformation. After extracting the indicators of the implementation of digital transformation through interviews and combining it with the indicators obtained from the review section of previous studies, the final statistical indicators were shown in the form of a secondary conceptual model and an analytical (operational) model. In the end, in order to prioritize the variables, a researcher-made questionnaire was used and distributed among the interviewed experts. Content analysis method was used to prioritize factors affecting digital transformation and analysis hierarchy process (AHP) was used for ranking. The findings of the theme analysis showed that organizational structure, digital leadership and management, digital strategy, digital technologies, digital talents and organizational culture were ranked first to sixth respectively.

Cryptocurrencies as one of the modern and emerging issues have been investigated in terms of various legal issues and various functions have been considered for them. One of these functions is their monetary function. According to this function, cryptocurrencies and the payment system based on it can be used to pay for the contractual consideration or to fulfill obligations. The basic issue in this payment is their legal validity. Considering that all cryptocurrencies are electronic, both in terms of their nature and the process of payment and transfer of funds, matching their performance with the legal foundations of electronic commerce is the most important legal issue. Based on these principles, the transfer of funds by cryptocurrencies as a data message that is carried out on the Internet, if it wants to be considered valid from the legal point of view and have a certificate, it must be created and maintained in a reliable information system. The existence of asymmetric cryptography, the existence of an encrypted hash function in the connection of blocks in the blockchain ledger, the use of digital signatures in sending funds, and the existence of a peer-to-peer and distributed network in the cryptocurrency payment system make it a secure system for transferring funds and storing transaction information. So this system has the necessary legal validity and can be legally protected as one of the payment methods.