Sharif Digital Repository

A semantic role labeler is a software that takes sentences as inputs and identifies the words or groups which have semantic roles such as Agent, Theme, Source, Instrument etc. The correct identification of semantic rols using computers can improve the quality of many natural language processing tasks such as information extraction, question and answering, text summarization and machine translation.Therefore a considerable amount of research has been carried out on this topic. Semantic role labelers normally use features extracted from the syntactic structure of the input sentences. That is why the syntactic representation used has a prominent role in the system's outcome. The research... 

To create applications for smart environments we can select from a huge variety of sensors that measure environmental parameters within the premises. Capacitive proximity sensors use weak electric fields to recognize conductive objects, such as the human body. They can be unobtrusively applied or even provide information when hidden from view which make these sensor more popular. Furthermore, these sensors are low cost, precise and low power. In this thesis, we study the construction and operation of capacitive sensors and the challenges of using them. Then we use them to produce smart devices. Smart flooring is used on the ground and it can be used to track people or fall detection. Smart... 

Audio signal processing is a greatly useful approach to the Internet of Things since analyzing prominent audio signals can provide valuable information about environmental activities. Environmental sound processing is used in applications such as mechanical systems diagnosis, industrial maintenance, security systems, etc. This approach requires the design and development of sound classification and detection systems. In this thesis, we have achieved 84.5% accuracy on optimizing the features (by feature engineering and feature learning) and exploiting different types of machine learning algorithms. Well-known databases such as ESC-50 have been used to test and evaluate the whole system. Among... 

In the last three years, the lives of many people around the world have changed with the spread of the Corona virus. In order to better manage the consequences related to the spread of this disease, extensive research has been done on this virus, and researchers in data science and artificial intelligence have devoted a part of their research to studying the effects of this virus on the people in one or different societies.On the other hand, the study of social networks about a specific issue or trend topic, allows us to examine more closely the atmosphere that governs the society and analyze the emotions, feelings and the level of concern of the members of the society about that issue.The... 

Replicating server information at shorter distances from users and delivering them at more suitable times, decreases average delay of serving requests as well as balancing backhaul link traffic. Due to limited cache size, cache placement strategies play key role in efficiency of such approaches. Well-known heuristic caching mechanisms such as Least Frequently Used (LFU) and Adaptive Replacement Cache (ARC), while quite efficient in terms of complexity, are not optimal in terms of hit rate which is the key caching performance index. In this paper, we address the optimal cache placement problem from an analytic Markov Decision Process (MDP)-based view to maximize cache hit rate. In this... 

Impulsive waves generated by landslides and slamming on horizontal cylindrical members of a jacket are examples of phenomena which cause damage on structures and endanger human life. Importance of wave generated by land slide was a motivation for a large number of analytical, experimental and numerical studies. Recently, numerical methods that do not use a grid have been used in order simulation and prediction of damage in these sophisticated hydrodynamic problems. One of these modern methods is Smoothed Particle Hydrodynamics (SPH). A general model based on Smoothed Particle Hydrodynamics, “SPHysics”, was developed jointly by researchers to promote the development and use of SPH within the... 

In wireless powered communication networks (WPCNs), wireless nodes are charged via an access point. In these networks, an access point transfers power to the nodes, and then, the nodes use the received power to transmit their information to the access point. Due to the wireless transmission of the information, eavesdropping of it is an important vulnerability in these networks. The conventional method to resolve this security problem is using cryptography algorithms. However, this method needs key management and complex encryption algorithms to be used by the nodes, which may not be applicable. Physical layer security (PLS), which uses the channel characteristics, is a more suitable way to... 

The daily development of societies and the advancement of various industries have led civil engineering to save on and use of environmentally friendly materials. Urban development and population concentration In some areas, Encourages engineers To use materials with more efficiency to design High-rise structures that have more lifetime or maintain them using modern methods. Concrete in most structures has a significant percentage of consumable materials, but it has limited tensile strength and flexibility. Fiber can be used to control the growth of cracks, prolonging useful life, controlling permeability and corrosion. Different types of fibers are used in concrete.In this study, we have... 

The daily development of societies and the advancement of various industries have led civil engineering to save on and use of environmentally friendly materials. Urban development and population concentration In some areas, Encourages engineers To use materials with more efficiency to design High-rise structures that have more lifetime or maintain them using modern methods. Concrete in most structures has a significant percentage of consumable materials, but it has limited tensile strength and flexibility. Fiber can be used to control the growth of cracks, prolonging useful life, controlling permeability and corrosion. Different types of fibers are used in concrete. In this study, we have... 

An α-labeling of a graph is a special case of graceful labeling which was introduced in the late 1960’s. Despite the large number of papers published on this subject in literature, there are few particular techniques to find labeling of graphs. There are still many open problems on this subject, some of which are well-known in Graph Theory. In this thesis, first we present and solve several new mathematical and constraint programming models to find α-labeling of 2-regular graphs. Then, a comparison between their results is discussed. Since, proposed models can only label small size graphs; a tabu search algorithm for labeling the big size 2-regular graphs has been developed. By labeling... 

Removing pollutants of water and, in general, wastewater treatment is one of the most important issues in the world. In this research, we synthesized a nanophotocatalyst based on znic-iron in the form of a magnetic core-shell Fe3O4@ZIF-8, and used to degrade the malachite green toxic color of wastewater. SEM, XRD and FT-IR analyzes have been taken and analyzed fore all three core, shell and core-shell composite catalysts.Due to the band gap of core-shell nanocomposite and the performance of the malachite green dye, a photocatalytic process under the visible light was obtained, which at an optimum amount of photocatalyst 0.003g, we reach 99.2% dye degradation at the 30ppm concentration. This... 

In this study, the effect of nano-structure mesoporous supports on the performance of the nickel catalysts in the combined reforming process was investigated. In the first part, magnesium aluminate spinel was prepared using a sol-gel method and employed as a catalyst support for the preparation of nickel catalysts with various nickel contents. The samples were characterized using BET, XRD, TPR, TPO, CO chemisorption and SEM techniques. The results showed that increasing the nickel content up to 7.5 wt.% improved the catalytic activity, but further increase in nickel content decreased the activity due to the decrease in the nickel dispersion. The catalysts except of the sample with 2.5 wt.%... 

Synthesis gas (H2, CO) is widely used in chemical and petrochemical industries, utilized for methanol and ammonia production. Hydrogen is the main component of syngas which is considered as an appropriate alternative for fossil fuels. Catalytic steam reforming is one of the most common and economical pathway for syngas production. Light hydrocarbons such as propane which can easily be transported, stored and distributed, is a promising feed candidate for steam reforming. Catalyst deactivation along with low stability resulting from carbon formation and sintering is one of the main crucial problems in this process, leading to much research on the preparation of stable and coke resistant... 

There are several methods for EEG state detection, and there are still many challenges. Switching Kalman Filter (SKF) is a suitable approach for state detection, which has been used in various applications such as QRS detection in ECG signal, apnea detection using ECG signal, and also hand path detection using EEG signal. Our goal here is to use Switching Kalman Filter (SKF) in order to detect changes in EEG signal, and in particular in sleep. In other words, we want to detect Sleep Stages. Here, detecting Sleep Stages will help doctors diagnose and treat diseases. There is a Kalman Model for each Stages of Sleep in SKF, that I model it with a AR model. In addition, SKF switch is a state... 

Non-linear loads have been increasing in industries resulting in high levels of harmonics in power networks. Harmonics have several negative effects including higher energy losses and lifespan reduction in equipment due to thermal loss. To reduce the levels of harmonics and consequently reduce the losses in power networks different methods of harmonic suppression have been employed. These methods are normally used at the customer’s side. In all of these methods, the idea is to prevent harmonics from flowing into a power network at the Point of Common Coupling (PCC). This research tries to reduce the harmonic losses by controlling the harmonic flow in a power network. Therefore, the solution... 

Most refineries are looking for a process in order to remove heavy compounds and convert them into lighter, more valuable materials. Among the various remaining upgrade processes, non-catalytic heating processes are very attractive and have gotten a wider scope worldwide because the feed used for the upgrade process is high in metal and sulfur, which causes the catalyst surface to become toxic and inactive. Due to that, the thermal cracking process is more suitable for such feeds than the catalytic cracking process. Due to the reduction of sweet crude oil resources and the heavier refinery feeds and increase in amount of global fuel needs, refineries must process a larger share of feed in... 

The main effort of this thesis is to present a numerical method to simulate and implement a special type of controllers, called proportional-weighted integral (PWI) controllers. For this purpose, at first mathematical equations of the fractional order proportional-integral controllers have been investigated in the time domain, and then by generalization of these controllers, the PWI controllers are achieved. Next the discretization of these controllers are carried out and the performance of the controllers are simulated by means of this discretization and comparison between these controllers and the conventional PI controllers has been held. After that a method for estimation of these... 

Bioorthogonal chemistry defines any reaction, inside or outside the living systems, without interfering with native chemical processes and 3dimensional structure of proteins. In these types of reactions water is the sole solvent; a neutral pH is required; the temperature must be up to 40 oC. The kinetics of reactions must be on the hour scale and the nontoxic reagents with low concentration must be used. One of the simplest methods of visualizing protein molecule is covalent attachment of fluorescein to protein. In this work several fluorescent compounds were synthesized. These novel compounds include acylchloride fluorescein, N-hydroxysuccinimide fluorescein, thiophenol fluorescein, and... 

In past decades, we have seen the rise of integration density in chips making it possible to design a whole system on a single chip. The previously designed interconnection architectures for multiprocessors systems cannot directly be applied in on-chip systems (especially when the number of processor elements increases) since they require a different type of a cost-performance trade-off. This is why the interconnection networks of systems-on-chip (SoC) are such a problem. Network-on-chip (NoC) was being proposed as a scalable and reusable communication platform for SoCs, which makes use of the network model to develop efficient on-chip communication infrastructures. The NoC has a layered and... 

The Smith Predictor does not work for unstable plants; therefore a lot of modifications have been proposed in order to solve this problem. In this project, advantages and disadvantages of most of these methods are studied in a general framework and based on Diophantine equation and using pole-placement technique. a discrete control scheme for unstable processes has been proposed. This structure can be used for non-minimum phase and stochastic processes. Robust stability of the suggested control structure has been shown. Performance of the proposed method is compared with previous works through computer simulations and its superiority for robust stability, load rejection; set-point tracking...