Sharif Digital Repository

According to the increase of interest in the internet of things, the importance of understanding the ongoing situation in an environment and acting upon them is largely considered. Due to the massive size of sensors used in a smart environment, there are plenty of data manufactured every second. Therefore, an interpretation of this data is mandatory to obtain valuable information to comprehend the situation ongoing in an environment. Situation recognition can bring a better understanding of the interaction between the smart actuators and sensors with the living agents in the environments.This will enable the system to help people do their routines, save energy, and accomplish more... 

Nowadays the combination of mechanical and electronic systems in small scales is gaining attention. Micro electro-mechanical systems are widely used in various industries such as car manufacturing and electronic chips. In these devices, the most important and useful mechanical structures are beams and plates. Therefore, investigating the mechanical properties of these structures in very small scales (micro and nano) is of great importance. Decreasing the size to these scales leads to the dependence of the behavior of these structures to size. Accordingly, some theories for prediction of these behaviors have been presented, one of which is the strain gradient theory. This theory is used in... 

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... 

Because of the high operating temperature, interconnect surface tends to be oxidized and Cr2O3 oxide layer will be created on the surface. This phenomenon is undesirable due to decreasing electrical conductivity, so a preservative coating is needed to improve the interconnect properties. In this paper, a dense spinel thin film was successfully synthesized on a ferritic stainless steel (type 430) substrate by a sol-gel dip coating method. This coating improved chemical stability, oxidation behavior of the substrate and decreased cathode poisoning. The Nickel-Cobalt spinel was coated on the substrate by sol-gel coating process. First, during a hydrolyze process, a stable sol was made up from... 

Because of the high operating temperature, interconnect surface tends to be oxidized and Cr2O3 oxide layer will be created on the surface. This phenomenon is undesirable due to decreasing electrical conductivity, so a preservative coating is needed to improve the interconnect properties. In this paper, a dense perovskite thin film was successfully synthesized on a ferritic stainless steel (type 430) substrate by a sol-gel dip coating method. This coating improved chemical stability, oxidation behavior of the substrate and decreased cathode poisoning. The lanthanum chromite was coated on the substrate by sol-gel dip coating process. First, during a hydrolyze process, a stable sol was made up... 

Plasma electrolytic oxidation process (PEO) is now recognized as a relatively new method in surface engineering. In this process, formation of micro arcs resulted from electric discharges on the surface of the specimen in the appropriate electrolyte, is used to ionize the gas layer which has enshrouded the specimen. In the present study, ceramic coating on aluminized steel was produced by PEO process and the effects of the influential parameters were comprehensively investigated. For this purpose, coating on the aluminized steel with dimension of 25×30 mm² was produced under different condition of processing time from 1 to 15 minutes, current density from 10 to 20 A/dm², frequency from 50 to... 

Because of limitation of titania coating that can act as self-cleaning surface under UV light irradiation, introduction of transition metal ions into titania lattice can decrease band gap energy of titania in order to activate the coating under visible light irradiation. In this research, by using vanadium element and silica prelayer, a titania coating was deposited on the soda-lime glass substarte to produce self-cleaning surface. The scope of coating was to increase the photocatalytic activity and hydrophilicity of vanadium doped titania coating on the soda-lime glass and silica coated glass by sol-gel dip coating method. XRD and FTIR analysis were done on the powders with different... 

Gelcasting is a new ceramic forming technique getting worldwide attention. The process is based on casting of slurry; containing powder, water and water-soluble organic monomers. The premix solution was prepared using Acrylamide as a monomer and Methylene bisacrylamide as a crosslinker with AM:MBAM ratio of 25:1, and Poly Acrylic Acid Sodium as a dispersant (1 wt% based on ceramic powders weight). A series of Al2O3/ZrO2 ceramic nanocomposites with 15, 17.5 and 20 wt% content of ZrO2 and 40, 43, 45, 47, 50, 53 and 55 vol.% of solid loading were fabricated by gelcasting. After casting the mixture, the monomer was polymerized to form gel parts. Drying, burning out and sintering completed the... 

Ceramic coatings on metallic substrates are used in many different applications. In biomaterials science, hydroxyapatite coating due to its similarity to the mineral part of bone structure is used to modification of implants surface. In this research, the HA/TiO2 double layer was coated on Ti-6Al-4V by sol- gel dip-coating method. After preparation of stable TiO2 sol, the Ti-6Al-4V substrate was dipped into the TiO2 sol. The speed of dipping was 10cm/min. After drying at 80°C, the TiO2 layer heat-treated at different temperature (350-500°C) for 1h. The HA outer layer was coated by dipping of Ti-6Al-4V substrate with TiO2 layer into HA sol, followed by heat-treatment at different temperatures... 

Solid oxide fuel cells as high temperature electrochemical devices draw much attention in the last decades due to their fuel flexibility, high efficiency and low pollution. However, lowering operating temperature from about 850°C to around 650°C without significant overpotential loss, in order to lower costs and increase cells life time has remained a challenge. Recently, a new family of mixed ionic and electronic conducting ceramics (MIECs) which are formulated Ln2NiO4+δ (Ln= La,Nd,Pr) and crystallized in Ruddlesden–Popper structure, have been regarded as appropriate cathode materials for the low or intermediate temperature solid oxide fuel cells (IT-SOFC). Amongst these compounds,... 

Nowadays, one of the most important research goals is to develop intermediate-temperature solid oxide fuel cells (IT-SOFC) operated at 500–800 °C. However, the large cathode polarization resistance caused by the reduced temperature is a major barrier against such an urgent demand for commercialization. In this regard, it is necessary to select a proper material as a cathode working efficiently at reduced temperatures without losing its desired performance. Various mixed ionic electron conductors (MIECs), especially Ruddlesden–Popper-type oxides, are used to improve the cathode performance at intermediate temperatures. Among these layered oxides, Pr2NiO4 has been reported to possess the... 

Li7La3Zr2O12 (LLZO) solid-state electrolyte is a very promising electrolyte for a variety of ion lithium solid-state batteries, due to high conductivity of Li ions at room temperature as well as its chemical stability with Li metal anode. LLZO phase has two tetragonal and cubic symmetries. The conductivity of the cubic phase is two times higher than that for the tetragonal phase. To stabilize the cubic phase at room temperature, 0.2, 0.25, and 0.3 mol% Aluminum was doped to LLZO solid-state electrolyte. This powder was synthesized by sol-gel combustion method at 1000˚C. The cubic phase and lack of impurity of the samples doped with 0.25 and 0.3% Aluminum were determined by X-ray Diffraction... 

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... 

Stock price patterns are a technical analysis approach to forecast future trends with tremendous practical benefits. However, the current algorithms solely rely on machine learning techniques and deep neural networks which could be a problem in countries where data sets such as these are not available. We propose an algorithm based on geometry and mathematics for this problem, leading to an O(n^3logn + n^2k) complexity, where k is the number of triangular patterns  

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...