Sharif Digital Repository

Demand estimation has always been one of the most important components of marketing in all industries. Because the profitability of any organization depends on the demand for the product or service that the organization offers to the market. On the other hand, in order to optimize the performance of the organization and better planning, we need to have an estimate of demand in order to avoid wasting the available facilities by optimally allocating resources. Another issue that shows the importance of demand estimation is the dependence of optimal pricing on the amount of demand, which can be said to be the most important tool of the organization to manage its revenue. Optimal pricing can be... 

Today, the importance of scientific collaborations is due to the fact that researchers who jointly publish an article, research connections are formed between them, and as a result, professional learning is obtained. Each of these researchers brings a feature and advantage to the research team, such as mastering a particular topic and its subdivisions, team thinking, and division of labor between them. The importance of these collaborations is doubled when researchers collaborate with each other at the international level, because the networking of researchers through collaboration with colleagues from different countries, especially central and developed countries in science, in addition to... 

The issue of spending companies' resources on marketing measures, due to the lack of a proper mechanism to explain the impact and role of these measures has always been one of the most challenging problems for many stakeholders of companies, especially managers. In this study, we have tried to explain the relationship between marketing costs and credit policies with the financial performance of companies by examining the information published by companies listed on the Tehran Stock Exchange. In this study, the required information was collected from the sources of valid tools and then, using statistical methods, regression models that express the relationship between variables were... 

Traffic accidents are one of the main causes of death in Iran. Between 2005 to 2019, 20,000 people were killed and 300,000 were injured on average annually. About 65 percent of all traffic fatalities over the past seven years has been on intercity roads. Finding patterns of accidents on specific days, such as holidays, would help the planners prevent traffic accidents. In this study, using police accident data, traffic counts of Road Maintenance and Transportation Organization, and meteorological data of Iran Meteorological Organization during 2011 to 2018, we study the effect of official holidays, and the days before, after and between two holidays on the rate and severity of road accidents... 

P/E ratio is studied in four levels in this study:
1)Macroeconomics level
2)Capital market level
3)Industry level
4)Company level
The first level studies effects of macroeconomics variables on P/E ratio. At this level we use variables such as economic growth, inflation, exchange rate, and etc.The next level uses capital market variables such as market volume, and IPO information.The third level that we study in this research is industry level. Stocks of an industry generally behave similar, because they have common advantages and disadvantages, thus industry is an effective factor on P/E ratio.The last level studies financial statements and internal features of a... 

Currently, in the Islamic Republic of Iran, after aviation accidents and incidents, conversations between pilots and air traffic controllers are re-examined by the State Air Transport Organization of the Islamic Republic of Iran and turned into text. The Automatic Recognition System for Pilot-Air Traffic Service Units’ Communication helps in the implementation of speech recognition. Reducing the time and cost of converting conversations into texts and creating an aviation database in the country are other uses of this system. In this research, after collecting and refining the actual conversation between pilots and air traffic controllers and examining seven methods, we design a system that... 

The topic of operations research and optimization is widely used in various fields, from transportation industries to military industries. Researchers in these fields seek to improve answers to problems and methods. In computer science, optimization methods are widely used. One of the most important problems in computer science are NP-hard problems; These problems are inherently not solvable in polynomial time. Therefore, the use of innovative methods, despite not guaranteeing the optimality of the solution, provide a suitable solution to bring the result closer to the optimal solution. Integer linear programming problems are also considered as NP-hard problems. The branch-and-bound... 

Network Function Virtualization (NFV) is a new paradigm for designing modern computer networks and data centers. NFV leverages the IT virtualization technologies to virtualize entire classes of network node functions into building blocks that may connect, or chain together to create communication services. In this research, we analysed and designed two offline and online algorithms for the problem of join optimization over placement and routing of network function chains in data centers. In the offline case, we showed that traditional randomized rouding works well and by help of chrnoff bound, we derive a new bound on performance gap. The online algorithm in both performance and resource... 

Cake Cutting is an old problem that studies how to allocate a resource among a number of agents to achieve fairness or maximize the revenue by selling the chunks fairly. The primary assumption in the conventional methods of studying Cake Cutting was that the allocator knows everything about the agents and their valuation functions for the different cuts of the cake, which could be impossible in real life. Here we addressed a new setting for an online Cake Cutting problem with unconnected pieces and studied four different objectives upon the setting. There we studied fair and efficient Online Cake Cutting by means of linear fairness and envy freeness. We also added a payment rule to study the... 

Processing of large graphs is the key component in many data analytics applications.We model the relationship of entities in different applications, such as web page ranking, social networks and tracking drug interaction with cells, using graphs. Graphics processing unit (GPU) is a well-known accelerator used for graph processing. Unfortunately, there are many challenges for mapping graph applications to GPUs efficiently. As graph applications have more kernel invocations and data transfers, using caches in these applications would be ineffective. Since vertices’ degrees of a graph are different, load distribution in many graph applications is not well balanced.Recently, matrix algebra has... 

Memories are one of the main component in the embedded systems, and owing to their vulnerability to error, this part of system must be fault tolerant. Single error correction (SEC) codes are one of the most commonly used methods against sot errors. However, on the other hands as the technology scales, multiple bit upsets (MBUs) are becoming more likely to occur in the memories and the SEC codes have lost their effectiveness in fault coverage. Therefore a greater attention is devoted to the codes with the higher fault coverage such as single error correction/double error detection (SEC/DED) codes. These codes increase the delay, area and power consumption overhead. These parameters are the... 

In many applications in human society, there is a need for identity recognition of people.Different methods have been developed for this purpose while using the biometrics is one of the major interests. The biometrics measure the unique physiological, anatomical and behavioural characteristics of people. Among them, face is an interesting biometric which have important advantages over other biometrics and face recognition is known as the most common method that people utilize to recognize each other. However, face recognition suffers from factors such as changes in head pose, illumination and face expression which influence the efficiency of recognition methods. The core of many recent... 

Real-time asynchronous data fusion for high-speed phenomena is an important and challenging task in the sensor networks. Examples of data fusion applications in sensor networks are: managing the traffic of maneuvering airplanes and ground vehicles in airside areas of an airport, traffic management in streets and roads, Driver Assistance Systems, guidance of antiaircraft and antimissile missiles. In all the data fusion applications the estimation of the required variables is necessary.
In this research two methods are introduced for real-time asynchronous data fusion, especially for track-to-track fusion of high-speed phenomena in sensor networks. The effectiveness and usability of these... 

A set of infected computers which are coordinated in some manner by one’s willingness and can perform malicious activities and provide threats in the cyberspace forms a network of bots, namely botnet. Botnet threats are more important and significant than other malwares due to their huge scale. A lot of computers coming together in a network obeying one’s commands allows their controller to conduct, for example, DoS attacks larger than ever seen incidents. This thesis, introduces botnets, their various threats, and an effective technique for detecting them. For this reason, different probable states of bots will be studied and modeled as a coherent bot life-cycle. The bot life-cycle allows... 

In nanometer technologies, the effect of process variation is observed in Multi-Processor System on Chip (MPSoC) in terms of variation in processors‟ frequency and leakage power. Traditionally, only worst case values of the system parameters were concerned and a worst-case optimization algorithm was employed for an application under design. As previous researches have shown these algorithms are not optimal in terms of parametric yield compared with newly employed statistical optimization algorithms. In this project, we have considered the problem of simultaneously selecting MPSoC architecture (which includes type and number of processors and the communication media) and task and... 

Surface water quality management needs water contaminants monitoring and information about water quality parameters. Field measurement is a costly, time-consuming procedure that limits information about the whole surface of a water body. Remote sensing methods are valuable ways that prepare water quality information using different characteristics between reflectance detected from each parameter. This study aimed to investigate the water quality parameters of Gorgan Bay using field sampling and a feasibility study using Landsat-8 and Sentinel-2 images to estimate the spatial and temporal changes of optically active parameters (such as sea surface temperature (SST), salinity, electrical... 

Autonomous vehicles will have a major impact on parking demands in urban areas in the future. Compared to conventional vehicles that should park near the destination of the passengers, autonomous vehicles can drop off the travelers at their destinations and then drive to the parking spaces by themselves. However, choosing a parking space in a far zone from the destination could lead to more travel demand in the network. We investigate traffic network equilibrium for traveling and parking with autonomous vehicles under a fully automated traffic environment. We introduce a Bi-level model, considering parking choices in the upper level and route choices in the lower level. The upper-level... 

Optimal use of available resources for construction projects depends on proper decision-making on how to spend resources. Optimization of resource consumption should be done taking into account project revenue. In this regard, investors need a suitable mechanism to predict the selling price of the construction project and the resulting profit. Therefore, investors and stakeholders need a suitable model with the help of which they can make decisions such as choosing materials to guarantee the desired profit from the sale. This research will provide a framework for constructing models for estimating the price of residential units by considering some features of the building and some economic... 

This study evaluates the impact of fuel price increase on urban and interstate travel demands via the linear regression model. Indeed this study has two aims. First, analyze the effect of fuel price increase on travel demands of two modes of transit ridership (Subway and Bus Rapid Transit), and determine the cross elasticity of demands. To achieve the demands, the origin-destination matrix of each mode was obtained using automated fare collection data and the trip-chaining method. Second, examine the impact of fuel price increase on interstate travel demands and provide the elasticity of vehicle-kilometer traveled with respect to fuel price. The ordinary least-square method was used to... 

In today’s world, people’s tendency to use their own vehicles is relatively high since private cars provide more convenience, better safety, and better time management than public transportation, but cause more traffic in the streets. Ride-sharing is one of the management tools that has attracted a lot of attention in recent years to mitigate the traffic congestion. Also, electric vehicles are used for public transportation in many parts of the world to achieve a sustainable environment. In this study, we assume that passengers’ origin, destination, and preferred time windows for pick-up and drop-off are known in advance. The aim of the study is to determine the sequence of visiting travel...