Sharif Digital Repository

Ultrasonically assisted machining process has been introduced as an effective solution to improve machining quality of mechanical parts. This study aims to reduce the drilling induced delamination to increase mechanical properties of CFRP laminates. Delamination decreases the strength of laminates under static and dynamic loads. Drilling parameters (feed and spindle speed) and ultrasonic vibrations amplitude are chosen as design experiment factors. Taguchi design of experiments method is used to study the effect of input factors on drilling thrust force, delamination factor and residual strength of drilled laminates. Input factors are in three levels and Taguchi L9 array is utilized. To... 

One of the important questions in religious studies, is that why many people are religious or at least have tendency to religion. Some thinkers believe that religious experiences can be explained appropriately by methods based on natural sciences. In fact, we can explain religious experiences and beliefs by accepting naturalistic view. Evolutionary religious studies (ERS) is one of these doctrines about the root of religion, which claims that human nature and mind are the most important factors in religious actions and beliefs. So in order to find better knowledge about religion, we must study human mind. Human mind and nature are made through natural selection; so what is basic in religion... 

In this dissertation, the location and severity of the damage are obtained using a new robust Power Spectral Density (PSD) sensitivity-based model updating method. PSD of structural response is highly sensitive metric to parameter change and provides vast information about the structure. The proposed damage detection method uses the sensitivities of measured responses in frequency domain, for FE model updating in an efficient way, by developing a quasi-linear sensitivity equation of structural response. The system of equations are solved using Least Square method. Only stiffness parameters were updated through model updating and change in mass parameters were neglected. In this study, proper... 

Isoquinolinonese are important structural compounds in plant alkaloids and useful synthetic intermediates for bio logically active compound some 3(2H)-isoquinolinone are known to exhibit biological effects such as antidepressant, cardiotonic, or analgesic activity. 3(2H)-isoquinolinone and its derivative are not so readily accessible. They have previously been synthesized by the reaction of o-acylphenyl acetic with ammonia, reaction of 3-isochromanon with amines this methods have problems like low yield and because of that we have developed practical and efficient route to synthesis 1٬4 dihydroisoquin-3(2H)-ones under microwave irradiation. We did this project with modified Pictet-Spengler... 

Treebanks are useful in many applications of natural language processing such as machine translation, speech recognition, information extraction, and etc. They are also being used in theoretical linguistics to study languages. For instance, they are valuable for development of different syntactic theories, calculation of frequency of syntactic rules, evaluation and comparison of statistical models and etc.
The most treebanks are based on phrase structure grammar or dependency grammar. In a phrase structure treebank, a sentence is divided to phrases. In this representation, a phrase is composed of several words. But in the dependency treebank, connection between two words is based on the... 

In the complex and dynamic world of today's communication networks, Software-Defined Networking (SDN) with its flexibility and programmability has opened new horizons in network management. These networks, by decoupling the control plane from the data plane, enable centralized and efficient management. Despite these advantages, optimizing routing in these networks remains a significant challenge, and increased latency in SDNs due to centralized processing in the controller and communications between switches and controllers is a critical issue that can severely impact the quality of service. Traditional routing methods face numerous challenges due to their static nature and lack of... 

Fog computing is essentially the expansion of cloud computing towards the network edge, reducing user access time to computing resources and services. Various advantages of fog computing, including reduced latency, improve user experience; however, user mobility may limit the benefits of fog computing. By moving users from one location to another, their distance from a fog service and consequently the latency may increase. One solution to maintain latency within an acceptable range is the migration of fog tasks and preserving the distance between the user and available resources. Although some research has been conducted on fog task migration, none of them have considered load balancing in... 

Vehicular Ad-Hoc Networks enable communication between vehicles and roadside units over wireless communication channels. These networks have garnered significant attention in industrial and research domains, particularly in areas such as intelligent transportation systems, traffic management, and safety alert dissemination. However, they face numerous computational and communication challenges, including limited bandwidth, high interference rates, latency, and routing inefficiencies. These issues are further exacerbated by the dynamic nature and rapidly changing topology of the network, resulting in unstable communication links. Typically, mobile networks rely on batteries with limited... 

In recent years, natural disasters and catastrophic events have frequently disrupted supply chains, leading to significant supply shortages and inducing panic-driven consumer behaviors. These disruptions, coupled with the influence of social interactions and communication dynamics, have profound implications for consumer buying behavior. This dissertation investigates the interplay between panic intensity, social learning mechanisms, and consumer decision-making, with a focus on their impact on demand patterns and retailer profitability. Utilizing a framework that integrates social learning and belief-updating processes, optimal retailer strategies are derived based on empirical insights... 

Nowadays, adaptable, versatile and flexible nature of Flying ad-hoc Networks (FANETs) make them popular in many academic and practical fields such as real-time applications, civil applications, search and rescue operations, identification and logistics. FANETs are organized multi-UAV systems that can accomplish complex missions through cooperation and collaboration. The unique features of these networks, such as high mobility, low node density, high frequency of topology changes, and three-dimensional flight environment, create various challenges in communication, especially in packet routing. In this type of network, a subset of UAVs connects to the infrastructure, while the remaining UAVs...