Sharif Digital Repository

User-generated data in TripAdvisor.com consists of considerable amount of useful information that can help managers to provide better services to their customers. In this study reviews to all hotels of Tehran, Iran and Auckland, New Zealand on TripAdvisor.com as real data are selected and scraped by Java programming language. In addition, information about hotels (e.g. name of hotel, overall rating, hotel’s class, total reviews, and hotel’s amenities) and information about the reviews and reviewers (e.g. date of review, country of the reviewer, contribution rate, rate to the hotel, text of review, date of stay, trip type, and years in TripAdvisor) are extracted as well. 64 and 190 hotels of... 

Vaccinating the global population against Covid-19 is one of the biggest supply chain management challenges humanity has ever faced. Rapid supply of Covid-19 vaccines is essential for successful global immunization, but its effectiveness depends on a transparent supply chain that can be monitored. In this research, we have proposed an approach based on blockchain technology, which is used to ensure seamless distribution of the Covid-19 vaccine with transparency, data integrity, and full traceability of the supply chain to reduce risk, ensure safety, and immutability. Without a proper mechanism to track and guarantee the authenticity of vaccines, all involved members, including governments,... 

Home health care is one of the newest methods of providing services to patients in developed societies that can respond to the individual lifestyle of the modern age and increase of life expectancy. In this study, a new mathematical model is developed taking into account the flexibility of starting and ending locations of each nurse, according to the specific requirements of each service. In this context, there are some special services that require the picking of materials and health equipment from laboratory or force the nurse to return to laboratory to deliver the specimens and equipment. In the next step, this model is expanded to downgrading aspects by adding the objective of minimizing... 

Demand forecasting has always been a concern for business owners as one of the main activities in supply chain management. Unlike the past that forecasting was carried out by means of limited amount of information, today, forecasting is performed using machine learning algorithms and data-driven methods with the advent of new technologies and data explosion. Patterns and trends of demand, customer information and preferences, comments and suggestions, post-consumption feedbacks are some types of data which are used in these approaches. Considering the all mentioned changes, traditional statistical methods and techniques such as time series analysis have bias in predicting these kind of data... 

This study aims to develop a mathematical model for the equitable distribution of the drug or vaccine needed in a critical situation like the COVID-19 epidemic. This study has taken a unique look at the human dimension of social issues such as the cost of deprivation and equality. It seeks to ensure a fair vaccine distribution among priority groups and affected areas. Thus, it has developed a mixed-integer programming model to minimize distribution costs in the cold chain to reduce the social costs of the crisis while reducing logistical costs such as transportation, scarcity, and maintenance costs. To do this, we considered a three-tier chain consisting of a supplier, distributor, and... 

As an abrupt epidemic takes place, most healthcare systems are shocked by the surge in the number of susceptible patients’ demands, and decision-makers mostly rely on their frame of reference to deal with the emergency situation as soon as possible. This paper aims to provide a mathematical model as a reliable support for pharmaceutical supply chain planning for the case of the COVID-19 epidemic. Additionally, it aims to integrate cold and non-cold chains is to take into account various pharmaceuticals and vaccines. To propose a model for planning the pharmaceutical supply chains, a mixed-integer linear programming (MILP) model is used for a four-echelon supply chain design. This model aims... 

Due to unusual response of structures of buildings with irregularity in their architecture to dynamic excitations, to have a comprehensive knowledge of their behavior during earthquakes is of utmost importance. Building irregularities are in general divided into two major categories, namely Irregularity in Plane and Irregularity in Elevation, and one of the forms of the latter is where there is a split in the levels of the building. In this work, through a series of case studies, the effects of P- phenomenon on the behavior of steel split-level building structures were studied. 5, 10 and 15 story buildings with 5 and 6 bays, and level splitting of 30, 60, 90, 120 and 150 cm were studied. All... 

Mesoscopic hydrodynamic equations are solved employing a VOF based method to investigate the equilibrium shape of nanodroplets positioned over various topographic geometries of the supporting substrate for three-dimensional systems. By taking into account liquid-liquid and liquid-solid interactions a complex distribution for inter-molecular forces over the substrates (the disjoining pressure) is observed. In this research we show that motion of nanodroplets not only caused by contact angle difference in drplets two sides, but also depend on disjoining pressure parameters.Geometries with increasing complexities, from wedges to three dimensional edges and wedges, were explored with the main... 

Observations made after previous earthquakes have shown the crucial role of irregularities in initiating damage in buildings with irregularity, either in Plan or in Elevation. Since in existing Building Codes, there is no provision for the distribution of the Equivalent Static Loads for such buildings, designers have no option but to resort to Dynamic Analysis. In this work, the seismic behaviour of a group of two-dimensional steel building structures with irregularity in elevation, namely Split-Level buildings, was studied. The studied structures consist of a series of 5- and 15-storey frames having two parts with splitting distance of 150 cm. Both, moment-resisting and braced frames were... 

With the road transportation vehicles being widely used, concerns have been increased regarding their unwanted effects. Air pollution, climate change, and oil supply security are among these effects. Many alternative fuels and propulsion systems have been proposed to be used instead of conventional ICE vehicles in recent decades. This project intends to conduct a Techno-Economic comparison between different vehicle powertrains so as to select the suitable choice to substitute conventional ICE vehicles. The vehicle options are ICE vehicles using both gasoline and CNG as fuels, Hybrid Electric Vehicles (HEVs), Plug-in Hybrid Electric Vehicles (PHEVs), and Electric Vehicles (EVs). The amount of... 

Base plates as the connecting components of steel structures to their foundations, have a crucial role in the behavior of these structures. In order to limit the thickness of base plates hence their cost within reasonable values, various types of attachments (stiffeners) are normally added to them. In this project 6 different configurations, Models, for the base plate and its attachments were considered and studied through finite element analysis. Each Model was studied under the combination of biaxial moments and a range of compressive loads including 0, 0.05 P/Py, 0.10 P/Py and 0.15 P/Py, where Py is the plastic load of the column. The moment-rotation curves of all models under various... 

Reducing air pollutant emissions from vehicles is a difficult and time consuming procedure which needs utilizing of modern emission control equipment and setting strict regulations for car factories and drivers as well. How efficient these policies are and proposing operative solutions for air quality improvement depend on developing a sustainable model which is used in vehicle emission predictions and their share in total emissions. Emission factors are not constant values as they can be affected by various operational and ambient parameters. Development of Emission inventories calls for a huge number of measurements using different vehicles in diverse conditions. Thus, recognition of... 

The city of Tehran is dealing with air pollution problems for years. Providing a solution for this problem requires information about different pollutants emission sources. In this subjects, emission factors and emission models are essential tools for decision makers. Among different mobile emission sources in Tehran, motorcycles are of high importance. In this project, for the first time in Iran, exhaust gas pollutants emission of 66 motorcycles with different ages and engine displacement volumes were measured according to Euro-3 standard certification procedure. Measurement results showed that none of the tested motorcycles passed the Euro-3 certification limit on CO emission. Calculations... 

Homogeneous Charge Compression Ignition (HCCI) engines are the new generation of internal combustion engines which have diesel-like thermal efficiency, while they have low nitrogen oxide and soot emission. One of the major problems of HCCI engines is combustion timing control due to its dependence on reactivity of the charge and chemical kinetics. Moreover, limiting operation range between knock and misfiring is the other drawback of using these kind of engines. In the present work, partially homogeneous HCCI combustion in a single cylinder diesel engine is modeled using Computational Fluid Dynamics (CFD) coupled with chemical kinetics. Simulation includes the engine cycle from exhaust valve... 

Today air pollution has become one of the major urban management concerns. Air pollution could have dangerous effects on human health in short time or long time in many situations. Numerical modelling is one of the most applicable among different ways for predicting pollutant concentration like field measurement, physical model in wind tunnel, and simulation. Modelling of pollutant dispersion is a way for estimating concentration and aggregation of the pollutant near the surface and with different distances from pollution source. In different dispersion models, one of simplest is the Gaussian model. In this approach it is supposed that emission plume obeys from Gaussian distribution and is...