Sharif Digital Repository

This research was conducted to identify the mechanisms of how authentic leadership behaviors influence employees' moral behaviors and suggest the processes of this influence. In order to obtain more valid results, a parallel mixed method was used. In that, we employed a qualitative method (data collection through semi-structured interviews) and a survey (distribution of questionnaires). This design was used to test the proposed influence model and to deeply understand the phenomenon of authentic leadership influence on the employees’ moral behavior. In the qualitative phase, 32 in-depth interviews with purchasing agents were conducted regarding the willingness to accept bribes in a company... 

This thesis is concerned with an optimal trade-off between communication overhead and the number and size of neighborhoods in a distributed optimal control technique for large-scale systems that is based on the Jacobi iteration and two-layer architecture for communication. Although this method efficiently reduces computational overhead, continuous and proper data transfer between subsystems that are very often far from each other, is required to achieve an acceptable performance. However, limited transmission bandwidth and short communication range result in significant communication overhead. This causes significant time latency between measurement and applied calculated control actions,... 

In today’s world, knowledge of the statistical behavior of noise can tremendously affect the accuracy of target detection in radar systems. Therefore, radar systems commonly collect a secondary dataset of homogeneous noise and estimate the statistics of the gathered data, prior to attempting target detection. Specifically, in the case of Gaussian noise with a mean of zero, the entire statistical information of the noise is encoded in its covariance matrix. In practice, however, the challenge is that the training samples do not purely contain homogeneous noise. In fact, some samples contain non-homogeneous outlier signals that do not have the same distribution as the noise samples. In this... 

In this research, we design a compatible waveform for the purpose of high-quality synthetic aperture radar (SAR) imaging in conjunction with sparse recovery methods for image formation. The goal is to make the imaging system tolerable against the wide-band and narrowband electromagnetic interferences. Actually, we consider minimizing the mutual interference between our radar and coexisting licensed emitters and minimizing the jamming signal (unlicensed emitters) power while enforcing some constraints over the waveform features like peak-to-average-power ratio (PAPR). For the constrained optimization problem to design a proper waveform, we introduce a new constraint to the optimization... 

Multistatic radar has several advantages over monostatic radar (such as better detection), which are due to the use of different viewing angles and the difference in their clutter characteristics. Clutter in many applications (such as marine applications) has the property of being sparse in certain dictionaries. Therefore, the investigation of sparse clutter (such as sea clutter) is of particular importance. It is worth noting that the detection of targets in the vicinity of the sea faces difficulties due to the dynamics of the sea, which causes the Doppler spectrum to change with time and change in space. Considering the fact that the sea clutter is sparse clutter, one of the powerful... 

Physiotherapy is a major part of the rehabilitation process that is used to retrieve patients' physical ability. The recuperation feedback in the physiotherapy process has a twofold significance for both physiotherapists and patients. It helps patients regain their ability to recover more quickly, prevent recurrence of injury to the treated area and other areas, and motivate the patient to continue treatment. It also helps the physiotherapist to monitor the process of rehabilitation and ensure the correctness of the procedure. Meanwhile, many patients cannot maintain continuous workouts due to lack of access to the physiotherapist at home and inability to provide required feedback.In this... 

With the advancement of wireless technologies and sensing methods, numerous studies have demonstrated the successful reuse of signals from networks based on the IEEE 802.11 standard for human activity recognition. Recently, Channel State Information, available in newer commercial modems, has been widely used in research for achieving more accurate results. However, most studies collect and analyze samples by generating artificial traffic, such as downloading large files, short-interval pinging, or altering settings to increase beacon signal transmission rate. This approach contradicts the normal operating conditions of these networks. Additionally, in such studies, the transmitter and... 

Lots of micro hydropower potentials are spread all around Iran country. They have the capability to produce electricity for workhouses, residential areas, agricultural and animal husbandries and recreational tourism centers. Hence, Sharif University of Technology and Iran Water and Power Resources Development Corporation decided to design and produce three types of hydro micro turbines to cover all range of micro hydropower potentials available in Iran. These three types of micro turbines are Pelton, Banki and Axial and they are designed in order to cover high, middle and low heads in sequence. Frequency control of micro hydropower plants is so vital due to plant off-grid. The most prevalent... 

The resolution is one of the most essential factors in radar imaging. The range and cross-range resolution are inversely proportional to the radar bandwidth and the angular width, respectively. Increasing the bandwidth requires upgrading the hardware of radars and the cost of this procedure is high. Also, to increase the angular width, we need more time to scan the scene from different angles but due to reasons such as movements of targets in the scene, it is unachievable.According to these limitations, we can utilize some signal processing techniques to Improve the radar resolution. Super resolution algorithms are the common approaches to achieving this goal. In this research, we proposed a... 

The problem of joint design of transmit code and receive filter is considered in many application scenarios of multiple input multiple output (MIMO) radar systems. The performance of the joint design problem is evaluated with the signal-to-interference ratio (SINR) metric in the presence of noise. In such problems, the optimization problem is to maximize SINR on the receiver side with the constraints that are applied on the transmitted waveform. Our proposed method, RTR, is a manifold-based geometric method that performs better than the SDP method in terms of algorithm execution speed and calculation complexity. For simulation, we took sampled and real TIR with Target Aspect Angle (TAA) in a... 

Estimating the direction of arrival (DOA) of an impinging signal from an RF scattering object, and subsequently determining its location when there is no line-of-sight (LOS) channel between the object and receiver, is a challenging issue in sensing and wireless communication systems. This thesis presents a modified multiple signal classification (MUSIC) algorithm, utilizing a single-element receive antenna and harnessing the capabilities of reconfigurable intelligent surfaces (RIS) to tackle this issue. It is demonstrated that by leveraging massive low-cost passive elements able to reflect signals with different phase shifts in consecutive snapshots, RIS can generate linearly independent... 

Noise or noise pollution, is defined as an unwanted sound, produced mostly by motor vehicles in urban areas. If the noise exceeds its limit, adverse effects on users and citizens are expected. Thus the assessment of the noise level and its comparison with allowable values is mandatory. Traffic induced noise depends upon different factors such as traffic, weather, and, sound barriers. Noise pollution study has a long history all over the world. Many studies, mostly representing the outdoor noise pollution models, have been done in recent years. This paper presents an assessment of traffic-induced noise in a heavily traveled tunnel, locally referred to as Resalat tunnel, which is located in... 

Data collected from street networks show that travel time in urban street networks is a stochastic variable, whose range of variation increases with the congestion level. Work and school trips comprise the major part of morning peak volumes, whose common characteristic is that they need to be made on time. For this reason, these travelers are pessimistic in their route choice, and try to choose routes which are more reliable. Travel time standard deviation is one of the common measures for estimating travel time reliability that is related to properties of day-to-day travel time distribution on a particular route. Based on the empirical data collected from Tehran street network, this paper... 

With the advancement of automotive industry, the number of electronic systems that need to communicate with each other has increased. An effective strategy to meet these growing demands is using bus-based protocols, which can establish safe communication among numerous nodes with reasonable cost, weight, and space requirements. The objective of this thesis is the design and implementation of a transceiver based on the FlexRay protocol. The significance of this protocol lies in its ability to provide higher data transmission rates compared to other protocols like CAN and LIN, and its role as the foundational communication medium among various domains in modern vehicle architectures. In this...