• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1063
  • 358
  • 156
  • 97
  • 56
  • 29
  • 21
  • 14
  • 12
  • 10
  • 10
  • 9
  • 7
  • 6
  • 5
  • Tagged with
  • 2247
  • 830
  • 809
  • 344
  • 239
  • 229
  • 223
  • 223
  • 221
  • 219
  • 190
  • 189
  • 184
  • 170
  • 164
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

A sentiment analysis software framework for the support of business information architecture in the tourist sector

Murga, Javier, Zapata, Gianpierre, Chavez, Heyul, Raymundo, Carlos, Rivera, Luis, Domínguez, Francisco, Moguerza, Javier M., Álvarez, José María 01 January 2020 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / In recent years, the increased use of digital tools within the Peruvian tourism industry has created a corresponding increase in revenues. However, both factors have caused increased competition in the sector that in turn puts pressure on small and medium enterprises’ (SME) revenues and profitability. This study aims to apply neural network based sentiment analysis on social networks to generate a new information search channel that provides a global understanding of user trends and preferences in the tourism sector. A working data-analysis framework will be developed and integrated with tools from the cloud to allow a visual assessment of high probability outcomes based on historical data, to help SMEs estimate the number of tourists arriving and places they want to visit, so that they can generate desirable travel packages in advance, reduce logistics costs, increase sales, and ultimately improve both quality and precision of customer service.
112

Implementation of a brassboard prototype of a collision avoidance system for use in ground vehicles

Hannis, Tyler James 14 December 2018 (has links)
Accidental collisions involving wheeled industrial ground vehicles can be costly to repair, cause serious (even fatal) human injury, and lead to setbacks with tight operation schedules. Reduction of vehicle collisions carries numerous safety and financial incentives. In this work, an integrated collision avoidance package is developed to reduce the number of vehicle collisions. Utilizing feedback from on-board sensing devices, a model predictive control (MPC) algorithm predicts control options and paths, then disallows drivers to accelerate and/or induces braking of the vehicle if a collision is imminent. A prototype system is developed, implemented, and tested on an industrial vehicle to mitigate collisions with people and high-value equipment. Testing results show that control can be executed in real time by the proposed system, and that the proposed method is effective in preventing an industrial vehicle from hitting detected obstacles and entering restricted areas.
113

An investigation of the feasibility of Markov chain-based predictive maintenance models in integrated vehicle health management of military ground fleets

Driouche, Bouteina 06 August 2021 (has links) (PDF)
Integrated Vehicle Health Management (IVHM) systems use models and algorithmic techniques to process Condition-based Data (CBD) to offer prognostic information and actionable imperatives in support of Condition-based Maintenance (CBM) for the system. IVHM technology was first introduced by NASA to gather data, diagnose, detect, and predict faults, and support operational and post-maintenance activities in space vehicles. Eventually, it expanded to other vehicle types such as aircraft, ships, and land vehicles [1]. In recent years, the United States Army has been implementing a policy of CBM to transition from preventive to predictive maintenance [2]. One of the many challenges faced by the Army is the lack of accurate methods to assess ground vehicle reliability using modeling and/or simulation. This study aims at developing a Markov Chain-based algorithm that can detect anomalies and that is capable of accurately predicting the operational states of military ground vehicles. Several different Markov Chain Models (MCMs) have been developed and tested in their ability to predict the next state of a vehicle, given its current state (diagnostics and prognostics), and to examine how well a given model can detect unknown measurements (anomaly detection). A target of 90% Correct Classification (PCC) was established for all the vehicle performance data. The results suggest that it is possible to predict at a high level of accuracy the likely operational states of the military vehicles using MCMs. The anomaly detection test results revealed that MCMs can clearly distinguish a change in the performance data, that does not match the expected performance.
114

Look-ahead Control of Heavy Trucks utilizing Road Topography

Hellström, Erik January 2007 (has links)
The power to mass ratio of a heavy truck causes even moderate slopes to have a significant influence on the motion. The velocity will inevitable vary within an interval that is primarily determined by the ratio and the road topography. If further variations are actuated by a controller, there is a potential to lower the fuel consumption by taking the upcoming topography into account. This possibility is explored through theoretical and simulation studies as well as experiments in this work. Look-ahead control is a predictive strategy that repeatedly solves an optimization problem online by means of a tailored dynamic programming algorithm. The scenario in this work is a drive mission for a heavy diesel truck where the route is known. It is assumed that there is road data on-board and that the current heading is known. A look-ahead controller is then developed to minimize fuel consumption and trip time. The look-ahead control is realized and evaluated in a demonstrator vehicle and further studied in simulations. In the prototype demonstration, information about the road slope ahead is extracted from an on-board database in combination with a GPS unit. The algorithm calculates the optimal velocity trajectory online and feeds the conventional cruise controller with new set points. The results from the experiments and simulations confirm that look-ahead control reduces the fuel consumption without increasing the travel time. Also, the number of gear shifts is reduced. Drivers and passengers that have participated in tests and demonstrations have perceived the vehicle behavior as comfortable and natural. / <p>Report code: LIU-TEK-LIC-2007:28.</p>
115

Studies on using data-driven decision support systems to improve personalized medicine processes

Cameron, Kellas Ross 30 June 2018 (has links)
This dissertation looks at how new sources of information should be incorporated into medical decision-making processes to improve patient outcomes and reduce costs. There are three fundamental challenges that must be overcome to effectively use personalized medicine, we need to understand: 1) how best to appropriately designate which patients will receive the greatest value from these processes; 2) how physicians and caregivers interpret additional patient-specific information and how that affects their decision-making processes; and finally, (3) how to account for a patient’s ability to engage in their own healthcare decisions. The first study looks at how we can infer which patients will receive the most value from genomic testing. The difficult statistical problem is how to separate the distribution of patients, based on ex-ante factors, to identify the best candidates for personalized testing. A model was constructed to infer a healthcare provider’s decision on whether this test would provide beneficial information in selecting a patient’s medication. Model analysis shows that healthcare providers’ primary focus is to maximize patient health outcomes while considering the impact the patient’s economic welfare. The second study focuses on understanding how technology-enabled continuity of care (TECC) for Chronic Obstructive Pulmonary Disease (COPD) and Congestive Heart Failure (CHF) patients can be utilized to improve patient engagement, measured in terms of patient activation. We shed light on the fact that different types of patients garnered different levels of value from the use of TECC. The third study looks at how data-driven decision support systems can allow physicians to more accurately understand which patients are at high-risk of readmission. We look at how we can use available patient-specific information for patients admitted with CHF to more accurately identify which patients are most likely to be readmitted, and also why – whether for condition-related reasons versus for non- related reasons, allowing physicians to suggest different patient-specific readmission prevention strategies. Taken together, these three studies allow us to build a robust theory to tackle these challenges, both operational and policy-related, that need to be addressed for physicians to take advantage of the growing availability of patient-specific information to improve personalized medication processes.
116

The relationship between emotion intensity and episodic migraine in adult women

Hurley, Catherine 27 February 2024 (has links)
BACKGROUND: Identifying factors related to migraine onset is essential to effective treatment because it would allow patients to take prophylactic measures to reduce the likelihood of migraine occurrence. The experience of intense emotions is a potential factor affecting migraine onset. This study aimed to explore the relationship between day-to-day experience of emotions (specifically the intensity of sadness, happiness, anxiety/stress, and interpersonal stress) and migraine onset. METHODS: Thirty adult women with episodic migraine were recruited to engage in a 12-week monitoring period that involved wearing a Fitbit and answering daily questionnaires by mobile app. The daily questionnaires asked about headache occurrence and triggers, emotional intensity, and sleep. A series of linear regressions were carried out to understand the overall relationship between emotional intensity and the onset of migraine over the 12-week period. In addition, mixed effects models were used to explore the temporal relationship between participants’ reported emotional intensity on a given day and migraine occurrence the next day. RESULTS: The linear regressions for migraine occurrence and headache occurrence as a function of emotional intensity were not significant. However, mixed effects models showed that emotion intensity and migraine onset were significantly associated for happiness (estimate = -0.081; p = .027), anxiety/stress (estimate = 0.060; p = .040), and interpersonal stress (estimate = 0.12; p = .0017) but not sadness (estimate = 0.025; p = .46). CONCLUSIONS: Findings suggest that high levels of anxiety/stress and interpersonal stress predict onset of migraine the next day. Similarly, low levels of happiness predict onset of migraine the next day. However, these relationships are no longer significant when emotional intensity is averaged over the 12-week monitoring period. Taken together, these findings support the need for longitudinal research evaluating the temporal relationship between emotion and migraine occurrence, particularly because important relationships may be lost with cross-sectional studies. Furthermore, these findings point to the potential role of strong negative emotions and the absence of positive emotions in producing migraine.
117

Robust Model Predictive Control for Process Control and Supply Chain Optimization

Li, Xiang 09 1900 (has links)
<p>Model Predictive Control (MPC) is traditionally designed assuming no model mismatch and tuned to provide acceptable behavior when mismatch occurs. This thesis extends the MPC design to account for explicit mismatch in the control and optimization of a wide range of uncertain dynamic systems with feedback, such as in process control and supply chain optimization.</p> <p>The major contribution of the thesis is the development of a new MPC method for robust performance, which offers a general framework to optimize the uncertain system behavior in the closed-loop subject to hard bounds on manipulated variables and soft bounds on controlled variables. This framework includes the explicit handling of correlated, time-varying or time-invariant, parametric uncertainty appearing externally (in demands and disturbances) and internally (in plant/model mismatch) to the control system. In addition, the uncertainty in state estimation is accounted for in the controller.</p> <p> For efficient and reliable real-time solution, the bilevel stochastic optimization formulation of the robust MPC method is approximated by a limited number of (convex) Second Order Cone Programming (SOCP) problems with an industry-proven heuristic and the classical chance-constrained programming technique. A closed-loop uncertainty characterization method is also developed which improves real-time tractability by performing intensive calculations off-line.</p> <p>The new robust MPC method is extended for process control problems by integrating a robust steady-state optimization method addressing closed-loop uncertainty. In addition, the objective function for trajectory optimization can be formulated as nominal or expected dynamic performance. Finally, the method is formulated in deviation variables to correctly estimate time-invariant uncertainty.</p> <p>The new robust MPC method is also tailored for supply chain optimization, which is demonstrated through a typical industrial supply chain optimization problem. The robust MPC optimizes scenario-specific safety stock levels while satisfying customer demands for time-varying systems with uncertainty in demand, manufacturing and transportation. Complexity analysis and computational study results demonstrate that the robust MPC solution times increase with system scale moderately, and the method does not suffer from the curse of dimensionality.</p> / Thesis / Doctor of Philosophy (PhD)
118

CRITICAL ZONE CALCULATION FOR AUTOMATED VEHICLES USING MODEL PREDICTIVE CONTROL

Enimini Theresa Obot (14769847) 31 May 2023 (has links)
<p> This thesis studies critical zones of automated vehicles. The goal is for the automated vehicle to complete a car-following or lane change maneuver without collision. For instance, the automated vehicle should be able to indicate its interest in changing lanes and plan how the maneuver will occur by using model predictive control theory, in addition to the autonomous vehicle toolbox in Matlab. A test bench (that includes a scenario creator, motion logic and planner, sensors, and radars) is created and used to calculate the parameters of a critical zone. After a trajectory has been planned, the automated vehicle then attempts the car following or lane change while constantly ensuring its safety to continue on this path. If at any point, the lead vehicle brakes or a trailing vehicle accelerates, the automated vehicle makes the decision to either brake, accelerate, or abandon the lane change. </p>
119

A machine learning framework for prediction of Diagnostic Trouble Codes in automobiles

Kopuru, Mohan 01 May 2020 (has links)
Predictive Maintenance is an important solution to the rising maintenance costs in the industries. With the advent of intelligent computer and availability of data, predictive maintenance is seen as a solution to predict and prevent the occurrence of the faults in the different types of machines. This thesis provides a detailed methodology to predict the occurrence of critical Diagnostic Trouble codes that are observed in a vehicle in order to take necessary maintenance actions before occurrence of the fault in automobiles using Convolutional Neural Network architecture.
120

Predictive Modeling of Thunderstorm-Related Power Outages

Shield, Stephen, Shield 11 December 2018 (has links)
No description available.

Page generated in 0.0732 seconds