Browsing by Author "Sinha, Ankur"
Now showing items 21-40 of 45
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Essays on strategic interactions in vertical supply chains: on the role of inventory and technology
Balasubramanian, Ganesh (Indian Institute of Management Ahmedabad, 2023)"The past two decades have witnessed a shift from centrally managed supply chains to decentralized supply chains (Netessine, 2004). In decentralized supply chains, interests of individual members may not be aligned with ... -
Evolutionary algorithm for bilevel optimization using approximations of the lower level optimal solution mapping
Sinha, Ankur; Malo, P.; Deb, K. (Elsevier B.V., 2017)Bilevel optimization problems are a class of challenging optimization problems, which contain two levels of optimization tasks. In these problems, the optimal solutions to the lower level problem become possible feasible ... -
Exact methods for solving linear and nonlinear max-min problems
Nigudkar, Suyog (Indian Institute of Management Ahmedabad, 2022)This thesis focuses on developing exact solution methods for mixed-integer linear and nonlinear maxmin problems. The first essay proposes a tri-level min-max-min optimization problem (pM-FLPI) to design a resilient food ... -
Exact solution methods for non-convex optimization problems
Das, Arka (Indian Institute of Management Ahmedabad, 2023)"The thesis focuses on the development of efficient algorithms for solving the non-convex problems arising in different application areas involving operations and supply chains. In the first essay, we propose an exact ... -
Finding better alternatives than those considered in a multiple criteria data sample
Sinha, Ankur; Korhonen, Pekka; Wallenius, Jyrki (Journal of Business Economics, 2016-01)This paper suggests a preference-based method to calculate the probability of finding a better alternative than the ones present in the original data sample. Such a procedure would be useful, for example, while selecting ... -
A general purpose exact solution method for mixed integer concave minimization problems
Sinha, Ankur; Das, Arka; Anand, Guneshwar; Jayaswal, Sachin (ScienceDirect, 2023-02-10)In this article, we discuss an exact algorithm for solving mixed integer concave minimization problems. A piecewise inner-approximation of the concave function is achieved using an auxiliary linear program that leads to a ... -
A general purpose exact solution method for mixed integer concave minimization problems (revised as on 12/08/2021)
Sinha, Ankur; Das, Arka; Anand, Guneshwar; Jayaswal, Sachin (Indian Institute of Management Ahmedabad, 2021-03-01)In this article, we discuss an exact algorithm for mixed integer concave minimization problems. A piece wise inner-approximation of the concave function is achieved using an auxiliary linear program that leads to a bilevel ... -
A gradient-based bilevel optimization approach for tuning regularization hyperparameters
Sinha, Ankur; Khandait, Tanmay; Mohanty, Raja (Springer, 2023-09-29)Hyperparameter tuning in the area of machine learning is often achieved using naive techniques, such as random search and grid search. However, most of these methods seldom lead to an optimal set of hyperparameters and ... -
Hub interdiction & hub protection problems: Model formulations & exact solution methods
Ramamoorthy, Prasanna; Jayaswal, Sachin; Sinha, Ankur; Vidyarthi, Navneet (Indian Institute of Management Ahmedabad, 2016-10-25)In this paper, we present computationally effcient formulations for the hub interdiction and hub protection problems, which are bi-level and tri-level mixed integer linear programs, respec- tively. In the hub interdiction ... -
Hub interdiction problems: Models and solution approaches
R, Prasanna (Indian Institute of Management Ahmedabad, 2018)Hub-and-spoke networks are used in the operations of businesses like telecommunication, transportation and energy systems. The network has special facilities known as hubs which act as interim nodes between source and ... -
Improving penetration of broking business in India
Kumar, Pawan (Indian Institute of Management Ahmedabad, 2017)Since the economic liberalization, the Indian stock market has shown tremendous growth in size as well as value. Despite the post GFC muted global growth, there has been an increasing interest in the stock markets, both ... -
A multiobjective exploratory procedure for regression model selection
Sinha, Ankur; Pekka, Malo; Timo, Kuosmanen (Taylor & Francis, 2014)Variable selection is recognized as one of the most critical steps in statistical modeling. The problems encountered in engineering and social sciences are commonly characterized by over-abundance of explanatory variables, ... -
Multiple allocation hub interdiction and protection problems: model formulations and solution approaches
Ramamoorthy, Prasanna; Jayaswal, Sachin; Sinha, Ankur; Vidyarthi, Navneet (Elsevier, 2018-03-29)In this paper, we present computationally efficient formulations for the multiple allocation hub interdiction and hub protection problems, which are bilevel and trilevel mixed integer linear programs, respectively. In the ... -
Optimal management of naturally regenerating uneven-aged forests
Sinha, Ankur; Rämö, Janne; Malo, Pekka; Kallio, Markku; Tahvonen, Olli (Elsevier B.V., 2017)A shift from even-aged forest management to uneven-aged management practices leads to a problem rather different from the existing straightforward practice that follows a rotation cycle of artificial regeneration, thinning ... -
A review on bilevel optimization: from classical to evolutionary approaches and applications
Sinha, Ankur; Malo, Pekka; Deb, Kalyanmoy (IEEE, 2018)Bilevel optimization is defined as a mathematical program, where an optimization problem contains another optimization problem as a constraint. These problems have received significant attention from the mathematical ... -
A semantic review on the current cases in the Indian judicial system and recommendations
Gupta, Akash; Prakash, Shashi (Indian Institute of Management Ahmedabad, 2016)This project aims to classify cases pending in the Indian Judicial System in 10 broad categories using Semantic Legal Classifier. This is done using a data size of 435 cases which have been decided already by the Supreme ... -
SEntFiN 1.0: entity-aware sentiment analysis for financial news
Sinha, Ankur; Kedas, Satishwar; Kumar, Rishu; Malo, Pekka (Wiley-Blackwell, 2022-03-08)Fine-grained financial sentiment analysis on news headlines is a challenging task requiring human-annotated datasets to achieve high performance. Limited studies have tried to address the sentiment extraction task in a ... -
Solving bilevel multi-criterion optimization problems with lower level decision uncertainty
Sinha, Ankur; Pekka, Malo; Kalyanmoy, Deb; Pekka, Korhonen; Jyrki, Wallenius (IEEE, 2016)Bilevel optimization problems are characterized by a hierarchical leader-follower structure, where the leader desires to optimize her own strategy taking the response of the follower into account. These problems are referred ... -
Solving bilevel optimization problems using Kriging approximations
Sinha, Ankur; Shaikh, Vaseem (IEEE, 2021-03-21)Bilevel optimization involves two levels of optimization, where one optimization problem is nested within the other. The structure of the problem often requires solving a large number of inner optimization problems that ... -
Strategic interactions in vertical supply chains: on the role of encroachment and advance purchasing
Gupta, Ayush (Indian Institute of Management Ahmedabad, 2024)This dissertation analyzes strategic interactions between an upstream seller and a downstream buyer in three two-period settings: (i) when the seller opens a direct channel in parallel to an existing indirect channel (aka ...