Sharif Digital Repository

Contraction sections are an integral part of all wind tunnels, whether designed for basic fluid flow research or model testing. The location of the contraction, just upstream of the test section, makes it very important to achieve a high quality contraction design. The effect of a contraction on unsteady velocity variations is significant to increase the mean velocity. Furthermore, contraction has a suitable role on the turbulence reduction in a wind tunnel. The contraction itself further reduces the turbulence in terms of percentage of the wind speed. This is due to the increase of the wind speed by a factor equal to the contraction ratio. In this research, to investigation flow quality in... 

Recently, many studies show that Augmented Reality (AR) and Automatic Speech Recognition (ASR) can help people with disabilities. In this thesis we examine the ability of combining AR and ASR technologies to implement a new system for helping deaf people. This system can instantly take a narrator's speech and convert it into a readable text and show it directly on AR display. Also, with this system, people do not need to learn sign-language to communicate with deaf people. To improve the accuracy of the system, we use Audio-Visual Speech Recognition (AVSR) as a backup for the ASR engine in noisy environments. AVSR is one of the advances in ASR technology that combines audio, video and facial... 

This research focuses on physics-informed neural networks, which are trained to solve supervised machine learning tasks while adhering to physical laws described by general nonlinear partial differential equations. Previous studies utilized Gaussian process regression to develop functional representations designed for a given linear operator. However, despite the flexibility of Gaussian processes, solving nonlinear problems presents two major limitations: first, authors had to linearize each nonlinear term over time, and second, the Bayesian nature of Gaussian process regression requires specific assumptions that may limit the model’s representational capacity. For these reasons, data-driven... 

Based on fog computing paradigm, new applications have become feasible through the use of hardware capabilities of smart phones. Many of these applications require a vast amount of computing and real-time execution should be guaranteed. Based on fog computing, in order to solve these problems in is necessary to offload heavy computing to servers with adequate hardware capabilities. On the other side, the offloading process causes time overhead and endangers the real-timeliness of the application. Also, because of the limited battery capacity of the handheld devices, energy consumption is very important and should be minimized.The usual proposed solution for this problem is to refactor the... 

Investors highly value the ability to predict the behavior of the capital market. Over time, various methods have been introduced to forecast the future of this market and anticipate its movements. A novel approach to achieving this is by developing data-driven decision support systems that can assist investors in making informed trading decisions. The opinions of experts play a crucial role in shaping people's perception of the market, which ultimately affects its final behavior. In this study, we have created a decision support system that can help investors by considering the complexities and meaningful relationships between different aspects of the problem. We have developed frameworks... 

With the rapid advancement of artificial intelligence technologies, particularly large language models, the automatic generation of educational content has attracted significant attention among researchers and instructional designers. The importance of this topic lies in the fact that designing and developing educational courses is a time-consuming and costly process, while many educational institutions and instructors seek to leverage modern tools to provide learners with relevant, interactive, and effective content. At the same time, the quality of the content and its alignment with psychological principles of learning and instructional design play a crucial role in the effectiveness of... 

the purpose of this research is to construct the facial image of a person from corresponding DNA. In this problem, we have a set of DNAs and facial images and we want to find the relation between the DNA and the features of facial images.using this relation we can find the facial Image of a person using the DNA. for this purpose we should first extract the features of faces that have the most variation among the population. by studying the feature extraction methods in this field, we borrow the deep neural network method that is used in face recognition fields.we found significant relations between DNA and extracted features from this network. finally using this relation we can predict the... 

The effect of alloying elements such as Chrome, Molybdenum and Chrome-Molybdenum on microstructure and mechanical properties of submerged-arc weld of structural St37 and 4135 Chromoly Steel was investigated. Addition of alloying elements was done through flux and slag-weld metal reactions. Bonded flux was used to achieve this purpose. Mechanical properties were studied by means of Longitudinal Tensile, Hardness and Charpy V-notch tests. Microstructure was studied by means of Optical and Scanning Electron Microscope. The results show that chromium increase Ultimate Tensile Strength (UTS) and impairs Impact Toughness (IT), although it increases the percentage of acicular ferrite (AF). In the... 

High mixing efficiency and high liquid-liquid mass transfer rate are two key features of spinning disk contactors. This work presents the experimental investigation of mixing and liquid-liquid mass transfer characteristics in a new double coaxial spinning disks contactor. The micromixing efficiency was investigated using a standard system of competitive parallel reaction known as iodide/iodate test reaction. The influences of various operating conditions such as the rotational speed of the disks, the direction of rotation, the feed radial location, the feed distribution pattern, the distance between the disks, and the feed flow rate on the mixing quality were examined carefully. The obtained... 

Detecting out-of-distribution (OOD) input samples at the inference time is a key element in the trustworthy deployment of intelligent models. While there has been a tremendous improvement in various flavors of OOD detection in recent years, the detection performance under adversarial settings lags far behind the performance in the standard setting. In order to bridge this gap, we introduce RODEO in this paper, a data-centric approach that generates effective outliers for robust OOD detection. More specifically, we first show that targeting the classification of adversarially perturbed in- and out-of-distribution samples through outlier exposure (OE) could be an effective strategy for the... 

Today, the correct management of construction projects in IRAN's water industry has become a severe concern for its managers. Construction projects of the water industry constitute a considerable part of the country's construction industry. Several significant Issues such as operation management, water industry projects, correct management of resources, crisis management in the water industry, increased productivity and useful life of structures, increasing productivity, and preventing water loss are among the determinative challenges in construction projects in Iran. One of the new methods for the correct management of the life cycle of projects in this area is the use of Building... 

Video games with respect to an ever Increasing player pool and Industry growth, have attracted a lot of attention in recent years. Dota 2, as one of the most successful games both in casual gamers’ community and E-sport community, is considered as a proper case study, however, most of the research done was limited to predicting games’ outcome. Despite The popularity, the rather unintelligent AI of the game has made quite a frustrating experience for new players. In this research, with a novel approach, hero features are used to predict their future positions. For this purpose, 35 professional games are collected and analyzed and 601 features are extracted. Then, suitable features are... 

The municipality is an administrative, public and non-state institution that falls into the city district of the most countries’ administrative divisions. This institution has relatively autonomy and independent power. Municipalities are trying to apply the best approaches (Such as Building Information Modeling (BIM) as a procedure contributing the project management) to save time and money, as well as to satisfy the citizens in the implementation of civil projects. This study examines and evaluates the readiness of municipalities to modify the construction projects based on BIM. In addition, a pattern for identifying BIM applications, evaluating the organization readiness and the needs of... 

The competition for staying in the business world has intensified today with the rise of open-source and commercial software. As long as a software is tailor-made to suit the needs of users, it is so-called alive and can stay in the competition. So the maintenance phase is necessary to make changes to the software to meet the needs of users. To reduce costs associated with this phase, it is necessary to avoid software bugs. One way to avoid software bugs is to use peer code review. Peer code review has been recognized as one of the best software engineering principles of the last 35 years. This principle helps maintain the quality of the code due to changes made to parts of the code that... 

Deep learning algorithms combined with supervision rely heavily on labeled data, posing challenges in the data labeling process. Addressing this issue, researchers in the field of machine learning have focused on developing approaches to reduce the dependency on labeled data and improve the efficiency of data collection for labeling purposes. This thesis investigates the training of a classification model using data collected through a human-in-the-loop system. Notably, this research pioneers the application of active learning techniques to differentiate between political and non-political Persian tweets. The dataset introduced in this study is the sole available collection for this specific... 

One of the most significant factors for the on-time and successful implementation of construction projects is contract management. Proper management of construction contracts and assessment of potential risks in the bidding process and before its signing have a significant impact on preventing or reducing the occurrence of claims and disputes between the contract parties at various stages of the project. In this research, using the latest deep learning (DL) and natural language processing (NLP) state-of-the-art methods, and various deep neural networks (DNN) architectures a model has been developed for extracting Persian contract risk-prone clauses. In addition, this study provides a... 

Representation learning methods on graphs have enabled using machine learning methods on graphs' discrete structure by transferring them to a continuous domain. As graphs' structures are not always static and may evolve through time, dynamic representation learning methods have recently gained scholars' attention. Several methods have been proposed to enable the model to update the embeddings graph changes, or new interactions happen between nodes. These online methods could significantly reduce the learning time by refreshing the model as the changes occur, so we don't need to retrain the model with the complete graph information. Moreover, by using the temporal information of interactions,... 

There are a lot of ways to measure the soil compaction but all of them have some deficiencies like low precision, soil destructive, time consuming and etc. The usual ways to measure the compaction in Iran are so traditonal and have the above problems. To solve these problems, modern ways like intelligent compaction is recomonded to decrease the time and cost of compaction. The observor can also control the compaction of all the soil point to prevent any offenses by making the network between the rollers.In new methods the soil compaction is calculated by measuring the roller vibratory and usage of fourier transform from the drum response . To compact the soil more precisely and more quickly,... 

Many public projects in Iran are being developed with the participation of the private sector. Complaints, however, have arisen in both the public and the private sectors in many public-private-partnership (PPP) projects. It is claimed that the current PPP standard-form contract is unable to properly handle project risks. This investigation was set to improve risk responses in the PPP standard-form contract in the country. A comprehensive list of 66 universal PPP project risks was prepared by review of various related international research efforts. The list was refined to 36 risk items for the country in consultation with PPP project experts and assessing two PPP cases. These risks were... 

In the world of software development, Code Review is one of the most vital processes to ensure code quality and security. The textual content features in code review comments play a significant role in assessing quality and guiding the review process. This research aims to examine the importance and role of these features in identifying anti-social comments and improving code review processes. In this study, we first challenge the concept of toxicity in code review comments, which had previously been accepted as a concept in the field of code review. We focus on enhancing and automating code review processes by accurately and reliably detecting anti-social comments based on relevant...