Sharif Digital Repository

This research aims to introduce a nanocatalyst based on open-cell nickel foam (NiFm) with 40 pore per inch(ppi) to save energy during methane steam reforming (MSR), an endothermic reaction, by increasing catalyst thermal properties with improved progressive compression strength. The nanocatalyst is synthesized with a chemical stepwise synthesis approach, thermal-chemical pretreatment, pulsed electrocodeposition of Ni-Al2O3 (γ) nanoparticles, and calcination. Herein, a polyurethane (PU) nonconductive substrate is transformed to nickel foam by using replication sponge method. The purchased PU became conductive by nickel electroless bath using sodium hypophosphite with 5-15 (µm) thickness... 

Steel shear wall is a lateral load resistance system, which has been taken into consideration in recent decades for designing and reinforcing high-rise buildings. This system is comprised of steel filler panel surrounded by frame members including beams and columns. Steel shear walls are presently fabricated in two types, stiffened and unstiffened. According to numerous conducted research, it can be stated that the stiffened type has better seismic performance. The use of stiffeners with a great number of executive details is required to spend more time and costs on the construction sector. In order to solve these problems, some experimental and numerical studies have been conducted on... 

The aim of the work presented in this thesis is deal with some of the aspects in the FEM analysis of sandwich panels containing holes which comprised with foam core. It is a new topic in this field; so the activities that have been done about this case are poor with respect to its performances in engineering. The main emphasis is placed on the treatment of the foam core since the core often is the weakest part of the sandwich and therefore in many ways governs the capacity and lifetime of the whole sandwich structure. Because of increasing application including construction, aircraft and transportation, marine and etc., different load conditions are considered for the analysis and... 

Simulation of biophysical neural networks enables the interpretation and integration of fast-growing and different experimental datasets. The widely used NEURON simulator allows molecular-to-network simulation. However, it is still a very hard challenge to create large-scale models and operate parallel simulations applying NEURON. SUNY Downstate developed the NetPyNE means networks using Python and NEURON, which was funded by the New York State Department of Health and some other institutions. NetPyNE is a Python-based tool that enables the development of data-driven multi-scale network models in NEURON through both programmatic and graphical interfaces. It is a powerful tool for parallel... 

In this work, dispersion of a spinning projectile has been reduced by modifying its configuration and using a simple open-loop guidance. The traditional nose is replaced with a new nose with controllable fins, the spin of which is isolated from the remained body using a roller bearing. To check out the dynamic behavior of the projectile, non-linear simulations has been used which were developed at preceding research projects. To carry out this project, important errors that make the dispersion of the projectile have been investigated. Then, assuming projectile is controlled ideally, an open-loop guidance has been achieved and the appropriate times for the implemention of the guidance... 

Planning safe rendezvous and docking trajectories between two spacecrafts has a high importance in the space applications. In order to make two spacecrafts moving in different orbits closer, two stages must be completed simultaneously: First the implementation of rendezvous maneuver which deals with the generation of control/guidance commands leading to trajectories that lead the chaser towards the target. Second the docking maneuver incorporation which makes the two spacecrafts closer with the relative zero attitude. Various approaches have been dealt with till now using the analytical and numerical approaches generally considering rendezvous, not the docking maneuver. These approaches... 

Open data intermediaries, as the key species of the ecosystem, and since they are the primary consumers of open government data, are crucial to the ecosystem's growth. Without them, the data would be useless during the dissemination phase. This study aims to define the roles of open data intermediaries and explain how they are compatible with the value creation and sustainability of the open data ecosystem in order to fill a gap in the literature in this area. Two Iranian open data intermediaries, Rasmio company and Vinsabt group, which have been involved in the field of data pertaining to companies, have been studied for this purpose. The data for this study is qualitative and was gathered... 

In order to develop entrepreneurial strategies, having knowledge of the components that can affect and determine entrepreneurial income is critical. Using European social survey data, this paper examines the impact of education level of self-employed people on their entrepreneurial income in both direct and indirect way. In the indirect way, regarding to Schwartz' model, personal values play the role as a mediator in the relationship between education level and entrepreneurial income. The results show that conservation values, including security, conformity and tradition significantly and negatively affect entrepreneurial income. Meanwhile self-transcendence values, including benevolence and... 

The issue of global warming and environmental protection is an issue whose importance becomes clearer every day and requires the cooperation of all stakeholders. One of the key stakeholders are consumers. A significant part of environmental pollution is directly or indirectly related to consumer behavior. Understanding the decision-making process and the influencing factors on consumer behavior will help policymakers and legislative bodies to design more effective programs to modify the consumption pattern. Extensive studies have been done on this subject in various research fields. Two theories of planned behavior and value, belief, and norm have been examined in various researches and in... 

Entrepreneurial activities have always been considered and investigated due to the economic and social effects they have on societies. In research, in addition to the effects of entrepreneurship at the country level, attention has also been paid to its outputs for entrepreneurs. Since people choose this path according to their goals, values , and personal criteria, it is important and necessary to study people and examine the effects of this activity on them. Well-being is one of the concepts that has been considered in this regard. Well-being in general means experiencing positive emotions, avoiding negative ones, and evaluating life positively. Therefore, well-being is one of the things... 

The digital age and its interlace with the pandemic has led to rapid changes in various institutions, including higher education. One of the factors that changes higher education is the expansion of E-learning and Massive Online Open Courses (MOOCs). Although about 15 years have passed since its creation, the pandemic has expanded the E-learning infrastructure and given it more attention, so that now everyone Confesses the possibility of distance education. On the other hand, although the development of MOOCs platforms and their considerable acceptance has attracted the attention of higher education professors and future researchers in this field, it is not properly considered by the... 

In this research, we develop a Real Business Cycle model for Iran, as Small Open Economy. In this model, which is designed to measure the role of oil price shocks in Iran’s business cycles, the positive oil price shocks, as well as increasing the revenue of exporting oil, raises the price of oil-based tradable goods. Additionally, it causes the fiscal policy variables (taxes and government expenditures) to change. Also the productivity of this economy is fluctuated by oil price fluctuations. The model is estimated via Impulse Response Function Matching method using a SVAR model as the auxiliary model. The results from the theoretical model show that near 50 percent of non-oil GDP cycles and... 

Innovative small tech companies are required to often have cooperation with large companies in order to scale-up and commercialize their products. Such cooperation is referred as “Technological Cooperation” since it relies on development and commercialization of technology. In this research, as a multiple-case study in the arena of nanotechnology, five cases of technological cooperation are analyzed and key successful factors are identified. In this endeavor, 15 comprehensive interviews were conducted with both small tech companies and technology applicant companies, including experts of Nanotechnology Innovative Council (INIC) – playing the role of a mediator. Due to lack of a comprehensive... 

New century came with changes in a series of global macro trends, especially a greater dispersion of knowledge, which undermines the effectiveness of innovation based on internal R&D. Many of successful organizations responded to this problem by opening their borders to exchange ideas and make cooperation with external actors in their innovation activities, which is known as "open innovation". Innovation in the defense industry, which always deals with challenges to keep its readiness alive, is traditionally based on internal R&D. These industries, as well as civilian industries, face the new macro trends including budget cut and knowledge dispersion, which reduces the effectiveness of their... 

Conversational Question Answering (CQA) has gained significant attention in recent years due to its potential to facilitate natural language interactions between humans and machines. The ability to effectively incorporate relevant history turns, which are previous utterances in a conversation, plays a crucial role in improving the overall performance of CQA systems. In this master's thesis, we explore the importance of conversational question answering and propose a novel approach for selecting relevant history turns to enhance the accuracy and relevance of the system's responses. Initially, we provide an overview of the recent models developed for addressing the CQA challenge. We analyze... 

The existing continual learning methods are mainly focused on fully-supervised scenarios and are still not able to take advantage of unlabeled data available in the environment. Some recent works tried to investigate semi-supervised continual learning (SSCL) settings in which the unlabeled data are available, but it is only from the same distribution as the labeled data. This assumption is still not general enough for real-world applications and restricts the utilization of unsupervised data. In this work, we introduce Open-Set Semi-Supervised Continual Learning (OSSCL), a more realistic semi-supervised continual learning setting in which out-of-distribution (OoD) unlabeled samples in the... 

Open-source online social networks for project sharing and online social networks Q&A make use of tags and keywords for indexing, classification, and thematic search. users are responsible for selecting tags to identify their content, which can lead to human errors, or malicious users with improper tagging can lead to information corruption. Uncontrolled use of words also leads to the production of different types of tags, leading to redundancy or ambiguity. The most obvious advantage of tagging is the correct classification of information, which provides better services for relevant searches and requests. In this study, we propose a new model called TagBERT, which for the first time uses... 

Despite significant advances in dialog systems, data-driven dialog systems are often unable to have content-driven conversations and present real-world knowledge in the context which is due to the lack of knowledge-based conversations in the research datasets and the lack of external knowledge in their architecture. As a result, they are far from the real world and opendomain use-cases. The goal of this research is to introduce a dialogue system based on external knowledge and facts using Deep Learning that the external knowledge can be updated and, the model will adapt itself and take them into account to have a rich conversation. It must be noted that external knowledge is assumed as a... 

Today, with the development of information systems and the use of information technology in organizations and the act of IT department to become out of isolation mode and also alignment of IT with the strategies and goals of the business units, many believe that the information should flow in organization without any borders. In addition to having common points, each of these frameworks have different features that make organizations have difficulties in choosing between them. It should be noted that the implementation of two or more frameworks together, can waste time and money, cause lots of rework, and also can lead conflicting outcomes in their organizations. Enterprise architecture... 

Storage subsystem is one of the most important components of a computer system. As more valuable information such as bank transactions are being stored in storage subsystems,occurrence of an unrecoverable error can lead to a much bigger problem. A storage subsystem can be divided into software and hardware part. Previous works focused on fault injection in the higher layers of the storage stack and didn’t consider fault injection at the device driver level. In this thesis, the dependability of storage stack is evaluated using fault injection at the device driver layer. Various hardware and software faults that can occur in hard disks and solid state drives are studied and dependability of...