Academia.eduAcademia.edu

Generalized Pattern Search

description50 papers
group4,743 followers
lightbulbAbout this topic
Generalized Pattern Search is an optimization technique that iteratively explores the search space by evaluating points based on a predefined pattern, allowing for the identification of optimal solutions without requiring gradient information. It is particularly useful for solving non-differentiable or complex optimization problems.
lightbulbAbout this topic
Generalized Pattern Search is an optimization technique that iteratively explores the search space by evaluating points based on a predefined pattern, allowing for the identification of optimal solutions without requiring gradient information. It is particularly useful for solving non-differentiable or complex optimization problems.

Key research themes

1. How can preprocessed pattern structures and statistical characterizations improve the efficiency and effectiveness of generalized pattern search methods?

This research theme investigates the role of preprocessing patterns or characterizing the problem space, such as through covariance analysis or pattern databases, to enhance pattern search performance in complex search spaces. Preprocessing aims to reduce computational overhead during search by encoding or extracting structural information, enabling faster or more accurate identification of matching patterns or optimization steps. It matters because generalized pattern search often suffers from combinatorial explosion or costly evaluations, and informed search direction selection or heuristic computation can substantially improve scalability and solution quality.

Key finding: Proposes a novel approach that preprocesses sampled points from the objective function's fitness landscape and computes the covariance matrix to identify principal search directions as eigenvectors. Using these eigenvectors... Read more
Key finding: Introduces additive pattern databases as precomputed heuristic tables partitioned into disjoint subproblems, allowing their heuristic costs to be summed without overestimation. Demonstrates improved admissible heuristic... Read more
Key finding: Develops and analyzes multiple algorithmic techniques for tree pattern matching, crucial for executing tree-replacement systems efficiently. The work emphasizes indexing and preprocessing patterns to enable rapid subtree... Read more

2. What algorithmic strategies enhance multiple pattern matching over large or structured texts for practical applications?

This theme targets algorithmic innovations designed to efficiently handle searching multiple patterns simultaneously within large or structurally complex texts, such as DNA sequences, pan-genomes, or composite texts with degenerate symbols. It explores the construction of specialized indexes or automata (like BWT-based indexes or elastic-degenerate string models) and speed-up techniques that drastically reduce query times while handling the complexity arising from multiple pattern searching or non-determinism. The focus is on practical, scalable search methods with provable bounds and demonstrated empirical improvements, critical in bioinformatics and large text retrieval.

Key finding: Proposes an indexing method combining the Burrows-Wheeler Transform (BWT) of the reversed text with a pattern matching machine (PMM) constructed over multiple patterns to locate all matches efficiently. Key improvements... Read more
Key finding: Introduces two online algorithms for pattern matching in elastic-degenerate texts representing sets of similar sequences with non-deterministic segments. One algorithm achieves linear time in the compressed text size for... Read more
Key finding: Develops efficient data structures CPI-I and CPI-II to index circular patterns enabling fast queries over large texts. The work extends classical pattern matching to circular strings (all rotations of a pattern), with... Read more

3. How do heuristic design principles and evaluation metrics differ between A* and greedy best-first search in generalized pattern search?

This theme explores the challenge of constructing effective heuristics for greedy best-first search (GBFS), a suboptimal but scalable alternative to A*. Counter to A* where heuristics are optimized for admissibility and dominance, the paper highlights that heuristics effective for A* may degrade GBFS performance. It proposes Goal Distance Rank Correlation (GDRC) as a new metric aligned with GBFS goal, enabling heuristic construction tailored to GBFS. Insight into heuristic behavior in greedy settings informs better search performance in complex pattern search domains that rely on heuristic-guided search.

Key finding: Demonstrates concretely that heuristic dominance and average heuristic value, key for A* performance, do not guarantee effective heuristics for GBFS and may cause performance degradation. Proposes Goal Distance Rank... Read more

All papers in Generalized Pattern Search

This paper presents a novel method for Multifocus image fusion that combines anisotropic diffusion PDE filtering and convolutional neural network (CNN) feature extraction. The proposed method aims to preserve image edges and details while... more
This paper describes a class of frame-based direct search methods for unconstrained and linearly constrained optimization. A template is described and analyzed using Clarke's nonsmooth calculus. This provides a unified and simple approach... more
A direct search method for nonlinear optimization problems with nonlinear inequality constraints is presented. A filter based approach is used, which allows infeasible starting points. The constraints are assumed to be continuously... more
This paper reports the work done towards planning the trajectory for cooperative crane lifts. The location of the hook points between the pick and place positions are determined using a path-planner. These are inputs to the trajectory... more
Te mapping of the OA Entry (i.e. Scheda OA), the Italian most general content standard for cataloguing works of art, to RDF is based upon a subset of cataloguing elements described in the version 3.00 of the aforementioned standard 1 ,... more
Tonality – or the feeling of key in music – achieved crisp theoretical definition in the early 20th century, even as the musical avant-garde pronounced it obsolete. The notion of a general collapse or loss of tonality, ca. 1910, remains... more
This contribution focuses on the so-called “Virtual Building Explorer (VBE)”, an adapted game-engine, which is now being used for communicating architectural information as it provides an interactive display of 3D scenes. The paper... more
This contribution focuses on the so-called “Virtual Building Explorer (VBE)”, an adapted game-engine, which is now being used for communicating architectural information as it provides an interactive display of 3D scenes. The paper... more
To compare the difference between primary homoeopathic and conventional paediatric care in treating acute illnesses in children in their first 24 months of life. One hundred eight Indian singleton newborns delivered at 37 to 42 weeks... more
1.0 Introduction Waterflooding process is a secondary oil recovery effort that involves injection of water into an oil well reservoir to increase the underground pressure thereby increasing oil recovery (Grema and Cao, 2016). However,... more
Background: With change in the lifestyle peoples are suffering from haemorrhoids as a major health issue. It affects anal region and creates physical and psychological disturbances resulting in significant compromise in the quality of... more
The purpose of this research is to determine an estimate for actual optimal oil recovery through cyclic Gas-Assisted Gravity Drainage (GAGD) process in a heterogeneous sandstone reservoir under geological uncertainties. A robust... more
Molluscum contagiosum (MC) is an infection caused by an antigenically different type of poxvirus called Molluscipox virus. It is also called water warts and its skin lesion is also known as Mollusca, this is prevailing in children but... more
Acute Diarrhoea is a manifestation under "Gastrointestinal Disorders" and many other clinical conditions. A clinical, non-comparative, randomised study was undertaken to analyse the effect of the homoeopathic remedies in acute diarrhoeal... more
Consider the optimization of a stochastic system in which the objective is to find a set of controllable system parameters that minimize some performance measure of the system. This situation is representative of many real-world... more
Trajectory optimization of a robot manipulator consists of both optimization of the robot movement as well as optimization of the robot end-effector path. This paper aims to find optimum movement parameters including movement type, speed,... more
Evaluation of the economic benefit of field development projects in the oil and gas industry is naturally subject to subsurface uncertainties and risks. While high economic returns from produced volumes compensated for the lack of robust... more
The main goal of every investor to invest should be to get a return on the invested capital, for this purpose, investors should see the financial performance of the company before investing. The main purpose of this research is to... more
The efficiency of water flooding processes can be improved by installing intelligent wells which are good candidates for control and optimization. Optimal control theory based on adjoint formulations was found to be efficient for... more
In several robot applications the spatial trajectories of the robot motion are defined by the user, and must be tracked precisely. Executing the prescribed spatial trajectories of the motion of a robot, the dynamic properties of the robot... more
A novel continuous genetic algorithm (CGA) along with distance algorithm for solving collisions-free path planning problem for robot manipulators is presented in this paper. Given the desired Cartesian path to be followed by the... more
Determining optimum infill well placement has been one of most challenging events in overall field development strategy of any types of field. Because there could be a large number of possible candidates for new infill well locations, it... more
A Cartesian trajectory tracking system for manipulators is developed using optimal control theory. By including the Cartesian position in the state vector, transformation of the trajectory from Cartesian space to manipulator joint space... more
A Cartesian trajectory tracking system for manipulators is developed using optimal control theory. By including the Cartesian position in the state vector, transformation of the trajectory from Cartesian space to manipulator joint space... more
This stimulating collection attempts to rethink traditional Japanese culture in sophisticated contemporary terms. A remarkable upshot is that as Japan is brought into new perspective, the Western tradition itself is subtly altered 190... more
In this work, the well control optimization of the Olympus challenge is solved by two non-intrusive strategies that use the simulator as a black box. This reservoir model contains uncertainties on geological scenarios, in which the... more
In this work, we present a modification (refinement) of the ensemble-based method for constrained waterflooding optimization. The problem of determining life-cycle rate controls for both producer and injector wells that maximize the net... more
The problem of determining life-cycle rate controls for both producer and injector wells that maximize the net present value subject to well and field-wide capacity constraints is solved using an SQP algorithm. The required gradient is... more
Proxy models are widely used to estimate parameters such as interwell connectivity in the development and management of petroleum fields due to their low computational cost and not require prior knowledge of reservoir properties. In this... more
In this work, we present a modification (refinement) of the ensemble-based method for constrained waterflooding optimization. The problem of determining life-cycle rate controls for both producer and injector wells that maximize the net... more
The problem of determining life-cycle rate controls for both producer and injector wells that maximize the net present value subject to well and field-wide capacity constraints is solved using an SQP algorithm. The required gradient is... more
In this work, the well control optimization of the Olympus challenge is solved by two non-intrusive strategies that use the simulator as a black box. This reservoir model contains uncertainties on geological scenarios, in which the... more
Optimization in Robotics are applied to find the best solution for increasing the 3D space precision, reduce the vibrations, choose the optimal applied base point of the robots to minimize the time of application, finding constructive or... more
One of the most important problem to solve in the robots Kinematics and Dynamics is analyze of the joint's angular and linear accelerations. Because the movements of the robot's bodies going in the 3D space, the mathematical algorithm... more
Direct search is a methodology for derivative-free optimization whose iterations are characterized by evaluating the objective function using a set of polling directions. In deterministic direct search applied to smooth objectives, these... more
Recently production optimization has achieved increasing attention in upstream petroleum industry. Here, we evaluate derivative free optimization methods for determination of the optimal production strategy using a numerical reservoir... more
The research led us to a generalized formulation for the N-Pendulum [Simple] system, encompassing both dragless and drag-inclusive scenarios. The mathematical framework presented herein provides a comprehensive and rigorous basis for... more
This paper is concerned with waterflood optimization of oil recovery from thin oil rims of gascondensate fields. Such fields are notorious for gas and water coning problems, i.e. early gas or water breakthrough in producing wells, causing... more
The optimization of trajectories and actuator torques for a dual arm manipulation system is considered. Given the starting and nal con gurations, we nd the trajectories that minimize (a) the integral of the norm of the vector of... more
We develop a new framework, based on the Least Constraint, for programming robots to perform a task using a fault tolerant trajectory. We take a specification of the task, expressed as a set of constraints on the robot's configuration... more
This essay investigates how Leslie Marmon Silko, in her first novel Ceremony, envisions the politics of Native American cultural identity and sovereignty within the mainstream frame of Cold War national imperative. Attempting to reclaim... more
Cette these propose une analyse geographique de l'agriculture et de l'alimentation au Senegal. Elle interroge les politiques economiques et agricoles et elle met en evidence leurs impacts dans le processus de transformation de... more
Case Taking is an art of collecting all the facts about the patient using various tools like observation, perception, history taken as given by the patient or told by the attendant, clinical examination etc. in order to find a remedy for... more
An energy criterion for choosing the best type of manipulator for a specified task is developed. First, the energy required to perform the robotic task is calculated. Then the lower bound of the mechanical energy consumed by the various... more
Download research papers for free!