Sharif Digital Repository

Designing and evaluating the segmented production structures of the production system due to the variety of production systems is one of the important issues that have been considered in recent decade. In this research, the paradigm of designing a segmented production system has been studied to increase the adaptation of the organizational structure of production systems to changing and diverse behavior of the market as well as to increase the responsiveness to demand in the organization. The segmented production system provides production units to small, flexible and decentralized production units. The segmentation process used in this research uses an axiomatic design structure. The... 

Regarding to the emergence of quantum computers and advances in the large scale implementation of them, exploiting hard problems of coding theory is of great importance.This family of problems, like those of lattices, has an acceptable resistance against classic and quantum attacks. Thus, they can be replaced with hard problems in number theory and algebra. Increasing dominance of cyberspace made us highly dependent to it. Consequently, preparing tools and methods to mitigate future threats is necessary. Digital signatures constitute an important family of cryptographic primitives. Code-based digital signatures are mostly suffering from two main drawbacks: large public key and long time of... 

Nowadays, Multi-Object Tracking (MOT) plays a crucial role in various computer vision applications such as autonomous vehicles, surveillance, and robotics. Traditional MOT methods often struggle with challenges such as high errors when dealing with complex scenarios involving occlusion, scale variations, and object interactions. Recent advancements in deep learning, particularly Convolutional Neural Networks (CNNs) and Transformer models, have demonstrated significant capabilities in addressing these challenges. This thesis presents a study on the use of deep learning techniques, specifically CNNs and Transformer models, for solving the problem of Multi-Object Tracking. It begins by... 

Autoencoder, as an essential part of many anomaly detection methods, is lacking flexibility on normal data in complex datasets. U-Net is proved to be effective for this purpose but overfits on the training data if trained by just using reconstruction error similar to other AE-based frameworks. Puzzle-solving, as a pretext task of self-supervised learning (SSL) methods, has earlier proved its ability in learning semantically meaningful features. We show that training U-Nets based on this task is an effective remedy that prevents overfitting and facilitates learning beyond pixel-level features. Shortcut solutions, however,are a big challenge in SSL tasks, including jigsaw puzzles. We propose... 

Object recognition is a field of image processing with the purpose of object detection and determining its pose. There was a wide research of object recognition using 2d information. These methods are less efficient due to their sensitivity to view and scale. Today with development of 3d technology, 3d reconstruction of objects has been eased, thus there is a new trend of 3d methods. 3d object recognition uses 3d data and model to recognize objects more efficiently in different views and in occlusion and clutter. The related works are classified in three category of view-based, feature matching, and classification. In this research we attempted to improve one of the best feature matching... 

The behavior of pile foundations under earthquake loading is an important issue that affects the performance of structures. Design procedures have been developed for evaluating pile behavior under earthquake loading; however, the application of these procedures to cases involving liquefiable ground is uncertain. The performance of piles in liquefied soil layers is much more complex than that of non-liquefying soil layers because not only the superstructure and the surrounding soil exert different dynamic loads on pile, but also the stiffness and shear strength of surrounding soil diminishes over time due to both non-linear behavior of soil and pore water pressure generation. In this... 

Industrial wastewater treatment has always been one of the significant human being problems for the years. In particular, sewage containing heavy metals that, if discharged into nature, would have irreversible effects on the ecosystem and human health. Due to their toxic nature, heavy metals will reduce the efficiency of wastewater treatment systems if they are not efficiently treated. Also, the removal of Nitrate from the wastewater, which is one of the most stable nitrogen oxides, has always been a serious human problem in the treatment of effluents due to their high solubility in water. The simultaneous presence of nitrate and heavy metals in the effluent will cause many problems in the... 

Gold Coin Futures Market by contract delivery month of Dey, in 1387 as part of the capital market in Iran Mercantile Exchange started its activities. Each transaction in this market includes ten coins all gold (tamam bahar). Nowadays We have three symbols on each of the next three months are traded in an active market. In this market, any natural or legal person giving the guarantee fund with any of the agencies approved by the Stock Organization and in the terms of seller or buyer begin their trading. For transactions in order to succeed, we need to predict the rise or fall of prices to be a buyer in the rises and be seller in the falls. With considering the performance of Neural Networks... 

Software development process is a base ground for all software activities and ensures all aspects of the software. No quality is guaranteed without a definite process. Model-Driven Software Development process proposes an industrial method for software companies to produce the required software through model(s) and tools. On the other hand, Software Product Line imposes a set of frameworks and principles. As a result a tangible decrement of development time and cost along with an increment of quality is achieved. Mixing both processes creates a stronger industrial process in order to decrease the development time and cost. In this thesis, through a survey on both of the processes and related... 

The design and control of collective robots for different purposes has been one of the most interesting subjects in recent years. Interacting particles (both in engineering and nature) can not only be self-organized, but also show a myriad of amazing features. A lot of different types of collective motion can be seen in nature (like fishes, birds, bacteria, insects, to name but a few) which interacting with each other to form complicated patterns with ingenious purpose like foraging, predator escaping and so forth. Understanding these natural phenomena (like vortex formation) can be helpful in designing artificial systems, the usage of which are underwater or space vehicles performing a...