داریوش عباسی مقدم

Having timely statistics and information from existing uses is a requirement for proper management of natural and urban areas. Considering the extensive changes in land use and the need for managers and planners to be aware of the changes that have occurred in order to make policies and find solutions to solve the existing problems, it seems necessary to reveal the changes in order to determine their time trends. Land use is one of the vital aspects in managing natural resources and evaluating environmental changes. The main goal of this research was to use remote sensing techniques along with GIS and Landsat TM and ETM+ satellite data in the period from 1975 to 2021 to detect changes in land use in Kerman region.

Classification of land use classes, analytical methods and changes were implemented using ENVI 5.3 and ArcGIS 10.3 software. The first step in this study included transferring the coordinates of sample points on satellite images to different land use classes. These points along with the objective data collected from field visits and unsupervised classification maps that show the spectral characteristics of the ground surface using different applications were used as training points for analysis.

The findings of this research after creating maps using Land and detailed analysis shows important changes in the way land is used during the studied period. In particular, urban and residential areas have increased from 1184 hectares to 2160 hectares from 1975 to 2020, which indicates a significant and sustainable growth. This rapid growth of urbanization has happened especially from 1995 to 2015 and has increased by 60% from 975.6 hectares to 2478 hectares. Along with the increase of residential areas, the studied area has also seen a significant increase in dry and unused lands. In the 2021 land use map, about 18% of the areas are classified as unused land. Considering the environmental conditions of the region, such changes may cause serious risks to the people of the region. It is necessary to emphasize that the environmental effects of these changes in land use should be considered. Climatic conditions and higher vulnerability compared to other areas require comprehensive and planned changes in land use. These changes have not only changed the landscape of the region, but may also endanger the ecological balance and sustainability of the region.

Land use maps are essential tools for national and regional development planning. They provide information that shows the current state of land use, allows comparison of capabilities and potential, and designs measures to meet current and future needs. Through the analysis of land use changes in Kerman during the last 45 years, this study shows the impact of urbanization and population growth on the landscape of the region. Its results emphasize that responsible and sustainable changes in land management are necessary to reduce harmful environmental impacts and promote long-term growth. In addition, it emphasizes the great importance of remote sensing technologies and GIS in monitoring and managing changes in land use and provides valuable data for informed decisions by authorities and related organizations.

Underwater acoustic sensor networks (UASNs) have gained growing importance due to their desirable features and wide spread practical applications in many communication fields. Due to the high cost of underwater sensor nodes as well as implementation complexity, increasing the lifetime of UASNs is an important issue. Although relay nodes have an important role in reducing the transmission distance and energy consumption. But the efficient RNP (Relay Node Placement) to avoid the critical sensor nodes' elimination is the main problem, i.e., to preserve the connected network. For this aim this paper presents an innovative solution called an Efficient Relay node Setting (ERS) algorithm, which involves formulating the Relay Node Placement (RNP) as a non-convex optimization problem. Actually, due to the Difference Convex (DC) constraints the proposed RNP problem is a non-convex problem and finding an optimal solution is complicated. However, a novel transformation can be applied to DC constraints which converts the problem into its convex programming equivalent. Application of the convex programming offers the advantage of readily computing a global optimal solution. Simulation results confirm the superiority of the proposed scheme over the competing RA method in terms of network lifetime and efficiency.

Massive MIMO system is one of the advanced and attractive technologies for fifth generation of wireless networks. In such systems, base stations employ a very large number of antennas (Hundreds or even thousands of antennas). As a result, in these systems, capacity, spectral efficiency and energy efficiency increases in comparison with conventional MIMO systems. In the channel estimation, interference, which is produced by reuse of the same pilot sequences by different users of neighboring cells, is the most important factor in the performance limits. This phenomenon is referred to as pilot contamination. In this paper, pilot contamination is described and then the research works presented by the researchers on this topic has summarized. We categorize the different proposed mitigation techniques for pilot contamination using the following taxonomy: protocol-based methods, precoding methods, AOA-based methods, blind methods and smart pilot assignment methods. Finally, we propose a method based on smart pilot allocation, to reduce pilot contamination. Simulation results show that both uplink rate of user’s increases based on the proposed method and the accuracy of channel estimation improved greatly than exciting methods. Then we propose a method based on pilot precoding and protocol based allocation to reducing pilot contamination effects. In addition, we study a range of challenges and future research topics.

Underwater acoustic communication channels have particular characteristics such as: high attenuation, the time-varying nature of propagation environment and low speed of the sound, which make it difficult to send information through these channels. Due to the variability of the environment, communication channels in this media are doubly-selective in both time and frequency domain. The time-varying channel can be expressed using expansion basic functions in order to following the temporal variation of the channel. In this paper, orthogonal Laguerre functions expansion is used to express an underwater MIMO-OFDM acoustic communication channel in which the MIMO-OFDM system uses adaptive beamforming at receiver. In order to have matching between the channel and receiver in the proposed system, digital Laguerre filters is used instead of conventional TDL filters in the beamformer. The results show that the proposed system has low computational complexity. Also it has a considerable improvement in the performance of the underwater acoustic communication system.

The purpose of this paper is designing a communications system and the required protocols for store and forward (S&F) payload of a LEO satellite. Considering user's dispersion in diverse places, split channel reservation multiple access (SRMA) technique, is applied through users to access the uplink channel. Different modulation methods are analyzed and PSK modulation and non-coherent FSK modulation are suggested for payload downlink and uplink, respectively. An error detection technique based on Reed-Solomon (255, 233) is used in the payload to improve the link performance and SR-ARQ approach is selected which is more efficient than other ARQ techniques. Moreover, communication protocols of the user's network, file transmitting to the satellite and file receiving from that along with their implementation are explained in terms of software. Finally, an appropriate hardware is proposed for this subsystem. Comparison of our design and the design strategy suggested in [4] show that onboard hardware complexity of current paper is less than [4]. Furthermore, our coding, modulation and protocol and Doppler compensation scenario is more efficient than [4].

In recent years, Underwater Acoustic Communications (UAC) has been a great matter of consideration because of its importance in different areas such as commercial and military applications. Underwater acoustic communications channel is known as a time-varying and doubly selective channel in both time and frequency domains. The orthogonal frequency division multiplexing (OFDM) modulation is an effective technique to communicate over challenging acoustic channels. In addition, using multiple-input multiple-output (MIMO) systems increases channel capacity which results in high data rate communications. Recently, basis expansion models (BEMs) have been widely used to estimate an underwater acoustic channel. In particular, when the channel is time-varying, the BEM model can effectively estimates the channel with a reduced number of coefficients and low computational complexity. To improve the performance of a MIMO communication channel, various beamforming techniques have been proposed in different areas. Inspired by the basis expansion modeling of an underwater acoustic channel, in this paper we develop a BEM based adaptive space-time beamforming for both the transmitter and receiver of an UAC. The Laguerre basis expansion model is employed in the linearly constrained minimum variance (LCMV) beamformer to obtain an adaptive scheme for updating the beamforming weights at the transmitter and receiver and to optimize the system performance in real-time. Our Simulation results show that the proposed BEM based beamformer method improves the Bit-Error-Rate (BER) and Minimum-Square-Error (MSE) performance substantially for a Rayleigh fading underwater acoustic channel. In particular, our method improves the BER and MSE about 10dB and 4dB compared to the discrete prolate spheroidal sequence (DPSS) method.

Energy detector is one of the non-coherent receivers for impulse radio ultra-wideband (IR-UWB) systems using on-off keying (OOK) modulation. Energy detection for IR-UWB OOK systems gets accomplished based on a threshold value. In these systems, the threshold value depends on several parameters that should be determined in the receiver. In this paper, we propose a blind approach to estimate proper thresholds for the symbol decision. The performance of the proposed method turns out to be asymptotically comparable to that of the optimal threshold selection. The proposed algorithm was also improved using an optimum integration interval. By using a blind estimating of the channel time delay spread, the integration interval was adjusted. Simulation results show that this method improves the performance about 1.5 dB in BER of 10-4.

Local Vertical Generator is required for starting the imaging operation of the camera in spin satellites. When the satellite spins,this system should sense the earth and generate the starting pulse of the imaging operation for telemetry and camera. In the other word, this system active the imaging payload and telemetry system in appropriate time. To generate starting pulse,it used of infrared (IR) radiation from the Earth. Infrared wavelengths is from to which is used in satellite earth sensors. Optic's glass is made of germanium, which is transparent in this region. Germanium is readily machinable, and its low chromatic dispersion allow the use of simple and uncorrected lenses in IR imaging systems. In this paper design, and implementation of local vertical generator based on pyroelectric detector and its electronic for a spin satellite in attitude of 800 Km is presented.