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    Parallel importation and price competition in a duopoly supply chain

    , Article International Journal of Production Research ; Volume 53, Issue 10 , 2015 , Pages 3104-3119 ; 00207543 (ISSN) Shavandi, H ; Valizadeh Khaki, S ; Khedmati, M ; Sharif University of Technology
    Taylor and Francis Ltd  2015
    Abstract
    Nowadays, diversion of products distribution from authorised channels to the gray markets is one of the main challenges of manufacturers. Suppose an international supplier distributes the products in several countries with different prices. In parallel importation, there are unauthorised distributers who supply products with a lower price and import them to a higher price market. The problem of parallel importation considering a manufacturer and a competitor is analysed using the game theory approach in this article. We investigate the pricing strategy for manufacturers and the effect of unauthorised distributer on price, market share and profit. We also investigate the performance of... 

    Monitoring multivariate profiles in multistage processes

    , Article Communications in Statistics: Simulation and Computation ; 2019 ; 03610918 (ISSN) Bahrami, H ; Akhavan Niaki, T ; Khedmati, M ; Sharif University of Technology
    Taylor and Francis Inc  2019
    Abstract
    In some quality control applications, processes consist of multiple components, stations or stages to finish the final products or the services. Some quality characteristics in each stage of these processes (called multistage processes) can be represented by a relationship between a response and one or more explanatory variables which is named as profile. In this paper, a general model is proposed for monitoring multivariate profiles in multistage processes. To this aim, the multivariate form of the U transformation approach is first used to remove the effect of the cascade property between the stages. Then, three control schemes are employed to monitor the parameters of multivariate simple... 

    Time series forecasting of bitcoin price based on autoregressive integrated moving average and machine learning approaches

    , Article International Journal of Engineering, Transactions A: Basics ; Volume 33, Issue 7 , 2020 , Pages 1293-1303 Khedmati, M ; Seifi, F ; Azizi, M. J ; Sharif University of Technology
    Materials and Energy Research Center  2020
    Abstract
    Bitcoin as the current leader in cryptocurrencies is a new asset class receiving significant attention in the financial and investment community and presents an interesting time series prediction problem. In this paper, some forecasting models based on classical like ARIMA and machine learning approaches including Kriging, Artificial Neural Network (ANN), Bayesian method, Support Vector Machine (SVM) and Random Forest (RF) are proposed and analyzed for modelling and forecasting the Bitcoin price. While some of the proposed models are univariate, the other models are multivariate and as a result, the maximum, minimum and the opening daily price of Bitcoin are also used in these models. The... 

    Monitoring multivariate profiles in multistage processes

    , Article Communications in Statistics: Simulation and Computation ; Volume 50, Issue 11 , 2021 , Pages 3436-3464 ; 03610918 (ISSN) Bahrami, H ; Akhavan Niaki, T ; Khedmati, M ; Sharif University of Technology
    Taylor and Francis Ltd  2021
    Abstract
    In some quality control applications, processes consist of multiple components, stations or stages to finish the final products or the services. Some quality characteristics in each stage of these processes (called multistage processes) can be represented by a relationship between a response and one or more explanatory variables which is named as profile. In this paper, a general model is proposed for monitoring multivariate profiles in multistage processes. To this aim, the multivariate form of the U transformation approach is first used to remove the effect of the cascade property between the stages. Then, three control schemes are employed to monitor the parameters of multivariate simple... 

    Binary classification of imbalanced datasets: The case of CoIL challenge 2000

    , Article Expert Systems with Applications ; Volume 128 , 2019 , Pages 169-186 ; 09574174 (ISSN) Khalilpour Darzi, M. R ; Akhavan Niaki, S. T ; Khedmati, M ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    This paper presents some approaches based on data mining techniques to solve the prediction task of Computational Intelligence and Learning (CoIL) Challenge 2000. The prediction task of the contest is a direct mailing problem and the goal is to improve its response rate. The main issue in this competition is the incompatibility of the dataset in which the distribution of the classes of the target attribute is highly unbalanced. This in turn causes high error rate in identifying the minority class samples. Three different level methods including data-level, algorithm-level, and hybrid method are used to overcome this issue. The specificity, sensitivity, precision-recall, and ROC criteria are... 

    Single-replicate longitudinal data analysis in the presence of multiple instrumental measurement errors

    , Article Computers and Industrial Engineering ; Volume 141 , 2020 Moazeni, M ; Behbahani, M ; Khedmati, M ; Akhavan Niaki, S. T ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    In this paper, a novel method as a combination of the expectation–maximization (EM) algorithm and Variogram is proposed to decompose the longitudinal measurement errors in the absence of replications and the presence of multiple instrumental measurement errors. In the proposed method, multiple measurements are considered where the units are observed by several distinct instruments (gauges). The approach decouples the observed variance of the measurement model into the process and measurement system variances. In addition, it decomposes the variance of multiple instruments into the process and instrument variances. In the end, the proposed model is validated and tested based on simulated... 

    Monitoring multivariate profiles in multistage processes

    , Article Communications in Statistics: Simulation and Computation ; 2019 ; 03610918 (ISSN) Bahrami, H ; Akhavan Niaki, S. T ; Khedmati, M ; Sharif University of Technology
    Taylor and Francis Inc  2019
    Abstract
    In some quality control applications, processes consist of multiple components, stations or stages to finish the final products or the services. Some quality characteristics in each stage of these processes (called multistage processes) can be represented by a relationship between a response and one or more explanatory variables which is named as profile. In this paper, a general model is proposed for monitoring multivariate profiles in multistage processes. To this aim, the multivariate form of the U transformation approach is first used to remove the effect of the cascade property between the stages. Then, three control schemes are employed to monitor the parameters of multivariate simple... 

    An Online Portfolio Selection Algorithm Using Pattern-matching Principle

    , M.Sc. Thesis Sharif University of Technology Azin, Pejman (Author) ; Khedmati, Majid (Supervisor)
    Abstract
    According to the rise of turnover and pace of trading, accelerating of analysis and making decision is unavoidable. Humans are unable to analyze big data quickly without behavioral biases so, using machines to analyze big data seems critical. Hence, financial markets tend to apply algorithmic trading in which some techniques like data mining and machine learning are notable. OLPS which sequentially allocates capital among a set of assets aiming to maximize the final return of investment in the long run, is the core problem in algorithmic trading. This article presents an online portfolio selection algorithm. The online portfolio selection sequentially selects a portfolio over a set of assets... 

    Providing a Method Based on Signal Transformations and Machine Learning Tools for Forecasting in Stock Market

    , M.Sc. Thesis Sharif University of Technology Parhizkari, Amir (Author) ; Khedmati, Majid (Supervisor)
    Abstract
    Obtaining high profit is the ultimate goal of an investor in the financial market. The key to achieve high profits in stock trading is to find the right time to trade with minimum business risk. However, it is difficult, often, to make decision about the best time to buy or sell some stocks due to the extremely dynamic and volatile behavior of the stock market. In order to resolve these problems, two steps have been followed in this research:1) Create a model to predict the final price of the stock with small error rate, and 2) Suggest the best stocks for trading to the trader. In order to achieve the goals of the first step, the stock price data of Hcltech, Maruti, Axisbank is selected and... 

    A Hybrid Stock Trading Strategy and Stock Portfolio Creation on the Stock Exchange Using a Combination of New Data Mining Techniques and Technical Analysis

    , M.Sc. Thesis Sharif University of Technology Kamroo, Saeed (Author) ; khedmati, Majed (Supervisor)
    Abstract
    By expanding the use of IT and public access to financial markets, the number of players in this area has increased and the nonlinearity of the market has become more complex. Hence, investors need specific strategies that can make profitable investment by determining the time of purchase and sale of stocks. The purpose of this research is to provide a stock trading framework for strategic portfolio management. This framework uses daily values of 18 indicators of technical analysis as features and daily trading signals as data labels for training various machine learning models, such as support vector regression, k nearest neighbors, decision tree, artificial neural network and random... 

    An online portfolio selection algorithm using clustering approaches and considering transaction costs

    , Article Expert Systems with Applications ; Volume 159 , November , 2020 Khedmati, M ; Azin, P ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    This paper presents an online portfolio selection algorithm based on pattern matching principle where it makes a decision on the optimal portfolio in each period and updates the optimal portfolio at the beginning of each period. The proposed method consists of two steps: i) sample selection, ii) portfolio optimization. First, in the sample selection, clustering algorithms including k-means, k-medoids, spectral and hierarchical clustering are applied to discover time windows (TW) similar to the recent time window. Then, after finding the similar time windows and predicting the market behavior of the next day, the optimum function along with the transaction cost is used in the portfolio... 

    Proposing a Hybrid Approach based on Deep Learning Algorithms for Stock Market Prediction

    , M.Sc. Thesis Sharif University of Technology Mobasseri, Niloofar (Author) ; Khedmati, Majid (Supervisor)
    Abstract
    Now a day, stock price prediction is known as one of the most challenging activities in the financial field. Research in price prediction models in financial markets, despite its many challenges, is still one of the most active areas for research. The price of non-linear financial assets is dynamic and unpredictable. Therefore, it is very difficult to arrangement and predict financial time series. Recently, many studies demonstrate that checking the news published in relation to a stock can significantly improve the accuracy of the prediction model.Among the latest techniques available for stock price prediction, we can mention deep learning models, which due to their high ability to... 

    Monotonic Change Point Estimation in Multistage Profiles

    , M.Sc. Thesis Sharif University of Technology Sepasi, Shabnam (Author) ; Khedmati, Majid (Supervisor)
    Abstract
    In this thesis, a hybrid method is proposed to estimate the change point in the parameters of simple linear profiles in multistage processes under monotonic changes. In monotonic changes, the type of change is not known a priori, and the only assumption is the changes are of non-decreasing (isotonic) or non-increasing (monotonic) type. In the proposed method, at first, the stages and the parameters experiencing the change are identified and then, the changes occurred in these stages and parameters are identified and examined based on the moving window approach and support vector machine (SVM) algorithm. Finally, the maximum likelihood estimator of the change point is proposed. The... 

    A new DEA model for ranking association rules considering the risk, resilience and decongestion factors

    , Article European Journal of Industrial Engineering ; Volume 15, Issue 4 , May , 2021 , Pages 463-486 ; 17515254 (ISSN) Khedmati, M ; Babaei, A ; Sharif University of Technology
    Inderscience Publishers  2021
    Abstract
    In this paper, a novel data envelopment analysis (DEA) model is proposed for ranking the association rules. In this regard, a mixed-integer linear programming (MILP) model is proposed to determine the most efficient association rules where, an N-person bargaining game is used to create an interactive competition between the existing N-weights to get a better ranking. In addition, the proposed model is fuzzified by setting the ambiguous threshold of the indicators’ weight in each rule to improve the overall ranking of the rules. Finally, the risk, resilience and decongestion factors are also considered to increase the responsiveness of the models to different real-world conditions. The... 

    An Online Portfolio Selection Algorithm Using Recurrent Neural Networks and Controlling the Risk of Tradings with Value at Risk Method

    , M.Sc. Thesis Sharif University of Technology Karimi, Nima (Author) ; Khedmati, Majid (Supervisor)
    Abstract
    Nowadays, capital markets play a key role in the economies of countries. Hence, this market is expanding more and more every day. In such circumstances, traditional analysis methods such as fundamental analysis and technical analysis have lost their position due to low speed and accuracy. In recent years, automated trading systems have been proposed as a solution to these problems. The online portfolio selection, which sequentially allocates capital among a set of assets aiming to maximize the final return of investment in the long run, is the core problem in algorithmic trading. In this research, we present an online portfolio selection algorithm based on pattern matching principle.... 

    A Multi-agent Deep Reinforcement Learning Framework for Algorithmic Trading in Financial Markets

    , M.Sc. Thesis Sharif University of Technology Shavandi, Ali (Author) ; Khedmati, Majid (Supervisor)
    Abstract
    Algorithmic trading in financial markets with machine learning is a developing and promising field of research. Financial markets have a complex, uncertain, and dynamic nature, making them challenging for algorithmic trading. To cope with the challenges of algorithmic trading in financial markets, we propose a multi-agent deep reinforcement learning framework trained by Deep Q-learning (DQN) algorithm to perform financial trading. This framework consists of multiple cooperative agents, each of which trained on a specific timeframe, to perform financial trading on the collective intelligence of the agents. Numerical experiments are conducted on historical data of the EUR/USD currency pair.... 

    Graph Generation by Deep Generative Models

    , M.Sc. Thesis Sharif University of Technology Motie, Soroor (Author) ; Khedmati, Majid (Supervisor)
    Abstract
    Graphs are a language to describe and analyze connections and relations. Recent developments have increased graphs' applications in real-world problems such as social networks, researchers' collaborations, and chemical compounds. Now that we can extract graphs from real life, how can we model and generate graphs similar to a set of known graphs or that are very likely to exist but haven't been discovered yet? Therefore, this research will focus on the problem of graph generation. In graph generation, a set of graphs is a training dataset, and the goal of the thesis is to present an improved deep generative model to learn the training data's distribution, structure, and features.Identifying... 

    Assortment Planning and Pricing with Limited Inventory

    , M.Sc. Thesis Sharif University of Technology Arabi, Hossein (Author) ; Khedmati, Majid (Supervisor)
    Abstract
    It has always been a challenge for retailers to plan which of the available goods will be displayed to the customer and at what price for each. In practice, the limited storage capacity of goods, the limited capacity of shelves, or the limited capacity of displaying goods on a web page in online stores may make it more difficult to decide on the above issues. These issues have been addressed in the literature when demand for goods is clear or a good estimate of demand can be obtained based on sales data. The purpose of this study is to investigate multi period Assortment planning, pricing and inventory planning with respect to the limited capacity of storage and display of goods in a... 

    A Novel Model For Financial Fraud Detection Using Machine Learning Techniques

    , M.Sc. Thesis Sharif University of Technology Rahmati, Mahdieh (Author) ; Khedmati, Majid (Supervisor)
    Abstract
    Today, e-commerce systems are used by both types of users. Therefore, the systems will be exposed to systematic fraud, and fraud is one of the main sources of financial losses for organizations. Therefore, it is very important for organizations to use accurate methods to detect fraud. this field is one of the most important applications of data mining in finance. There are various challenges in fraud detection projects, and this research has divided these challenges into three categories, which are: data pre-processing due to the imbalance data set, the accuracy of the machine learning model, and uncertainty. In the first part, both oversampling and undersampling methods will be used in... 

    Phase-I robust parameter estimation of simple linear profiles in multistage processes

    , Article Communications in Statistics: Simulation and Computation ; 2019 ; 03610918 (ISSN) Khedmati, M ; Akhavan Niaki, T ; Sharif University of Technology
    Taylor and Francis Inc  2019
    Abstract
    This paper addresses the problem of robust parameter estimation of simple linear profiles in multistage processes in the presence of outliers in Phase I. In this regard, two robust approaches, namely the Huber’s M-estimator and the MM estimator, are proposed to estimate the parameters of the process in Phase I in the presence of outliers in historical data. In addition, the U statistic is applied to the robust parameter estimates to remove the effect of the cascade property in multistage processes and as a result, to obtain adjusted robust estimates of the parameters of simple linear profiles. The performance of the proposed methods is evaluated under weak and strong autocorrelations...