Assessing the reliability of general-purpose Inexact Restoration methods

Inexact Restoration methods have been proved to be effective to solve constrained optimization problems in which some structure of the feasible set induces a natural way of recovering feasibility from arbitrary infeasible points. Sometimes natural ways of dealing with minimization over tangent approximations of the feasible set are also employed. A recent paper Banihashemi and Kaya (2013)] suggests that the Inexact Restoration approach can be competitive with well-established nonlinear programming solvers when applied to certain control problems without any problem-oriented procedure for restoring feasibility. This result motivated us to revisit the idea of designing general-purpose Inexact Restoration methods, especially for large-scale problems. In this paper we introduce affordable algorithms of Inexact Restoration type for solving arbitrary nonlinear programming problems and we perform the first experiments that aim to assess their reliability. Initially, we define a purely local Inexact Restoration algorithm with quadratic convergence. Then, we modify the local algorithm in order to increase the chances of success of both the restoration and the optimization phase. This hybrid algorithm is intermediate between the local algorithm and a globally convergent one for which, under suitable assumptions, convergence to KKT points can be proved28

Economic inexact restoration for derivative-free expensive function minimization and applications

The Inexact Restoration approach has proved to be an adequate tool for handling the problem of minimizing an expensive function within an arbitrary feasible set by using different degrees of precision in the objective function. The Inexact Restoration framework allows one to obtain suitable convergence and complexity results for an approach that rationally combines low- and high-precision evaluations. In the present research, it is recognized that many problems with expensive objective functions are nonsmooth and, sometimes, even discontinuous. Having this in mind, the Inexact Restoration approach is extended to the nonsmooth or discontinuous case. Although optimization phases that rely on smoothness cannot be used in this case, basic convergence and complexity results are recovered. A derivative-free optimization phase is defined and the subproblems that arise at this phase are solved using a regularization approach that take advantage of different notions of stationarity. The new methodology is applied to the problem of reproducing a controlled experiment that mimics the failure of a dam

Electronic systems for the restoration of the sense of touch in upper limb prosthetics

In the last few years, research on active prosthetics for upper limbs focused on improving the human functionalities and the control. New methods have been proposed for measuring the user muscle activity and translating it into the prosthesis control commands. Developing the feed-forward interface so that the prosthesis better follows the intention of the user is an important step towards improving the quality of life of people with limb amputation. However, prosthesis users can neither feel if something or someone is touching them over the prosthesis and nor perceive the temperature or roughness of objects. Prosthesis users are helped by looking at an object, but they cannot detect anything otherwise. Their sight gives them most information. Therefore, to foster the prosthesis embodiment and utility, it is necessary to have a prosthetic system that not only responds to the control signals provided by the user, but also transmits back to the user the information about the current state of the prosthesis. This thesis presents an electronic skin system to close the loop in prostheses towards the restoration of the sense of touch in prosthesis users. The proposed electronic skin system inlcudes an advanced distributed sensing (electronic skin), a system for (i) signal conditioning, (ii) data acquisition, and (iii) data processing, and a stimulation system. The idea is to integrate all these components into a myoelectric prosthesis. Embedding the electronic system and the sensing materials is a critical issue on the way of development of new prostheses. In particular, processing the data, originated from the electronic skin, into low- or high-level information is the key issue to be addressed by the embedded electronic system. Recently, it has been proved that the Machine Learning is a promising approach in processing tactile sensors information. Many studies have been shown the Machine Learning eectiveness in the classication of input touch modalities.More specically, this thesis is focused on the stimulation system, allowing the communication of a mechanical interaction from the electronic skin to prosthesis users, and the dedicated implementation of algorithms for processing tactile data originating from the electronic skin. On system level, the thesis provides design of the experimental setup, experimental protocol, and of algorithms to process tactile data. On architectural level, the thesis proposes a design ow for the implementation of digital circuits for both FPGA and integrated circuits, and techniques for the power management of embedded systems for Machine Learning algorithms

ROBUST MODEL DEVELOPMENT FOR EVALUATION OF EXISTING STRUCTURES

In the context of scientific computing, validation aims to determine the worthiness of a model in supporting critical decision making. This determination must occur given the imperfections in the mathematical representation resulting from the unavoidable idealizations of physics phenomena. Uncertainty in parameter values furthers the validation problems due to the inevitable lack of information about material properties, boundary conditions, loads, etc. which must be taken into account in making predictions about structural response. The determination of worthiness then becomes assessing whether an unavoidably imperfect mathematical model, subjected to poorly known input parameters, can predict sufficiently well in its intended purpose. The maximum degree of uncertainty in the model\u27s input parameters which the model can tolerate and still produce predictions within a predefined error tolerance is termed as robustness of the model. A trade-off exists between a model’s robustness to unavoidable uncertainty and its agreement with experiments, i.e. fidelity. This dissertation introduces the concept of satisfying boundary to evaluate such a trade-off. This boundary encompasses the model predictions that meet prescribed error tolerances. Decisions regarding allocation of resources for additional experiments to reduce uncertainty, relaxation of error tolerances, or the required confidence in the model predictions can be arrived at with the knowledge of this trade-off. This new approach for quantifying robustness based on satisfying boundaries is demonstrated on an application to a nonlinear finite element model of a historic masonry monument Fort Sumter

A Review of Spinal ROM Measurement Tools

Physical therapists rely on measurements to communicate with one another, establish patient status, predict treatment response, document treatment efficacy, and claim scientific credibility for the profession. Therefore, the quality of measurements should be of great concern to physical therapists and, hence, therapists should be able to examine the quality of measurement tools they are using critically. A variety of measurement tools are being utilized in physical therapy to quantify spinal mobility; however, there is no clarity as to which of the tools are optimal. In particular, the spinal range of motion measurement tools will be examined because of the high occurrence and high cost of low back injuries. The spinal range of motion measurement tools reviewed in this study include goniometers, flexible rulers, inclinometers, motion analysis systems, the Isotechnologies B-200, and the Spinoscope. The use of each of these measurement tools has advantages and disadvantages in a clinical setting. The reliability and validity of a measurement tool should be the most important considerations, but individual clinical needs and available resources also need to be considered when choosing an appropriate spinal range of motion measurement tool. If all these factors are considered, the author recommends the use of inclinometers since many studies show the inclinometer to be both reliable and valid. The EDI 320, in particular, is recommended for its ease of application. Finally, even if a tool is shown to be reliable and valid, established protocols for measurement techniques should be followed by each clinical staff member

Structural Damage Evaluation: Theory and Applications to Earthquake Engineering

The further development of performance-based earthquake engineering (PBEE) is on the current agenda of the earthquake engineering community. A part of assessing the seismic performance of civil engineering structures involves estimation of seismic damage. The conventional approach to damage estimation is based on fragility functions that relate some chosen parameters of structural response to incurred damage. Therefore, damage prediction is based exclusively on the knowledge of the chosen structural response parameters, meaning that damage analysis is uncoupled from the structural analysis. The structural response parameters selected for use in damage analysis are usually referred to as engineering demand parameters (EDP). In the present study, it is shown that for structural damage estimation, the uncoupled damage analysis has deficiencies that lead to less accurate damage prediction. These shortcomings originate from two sources: first, dependence of practically all EDPs on structural damage and second, inexact damage description. To overcome these deficiencies, another approach to structural damage estimation is proposed. The proposed approach, besides using an EDP, uses all information available from structural analysis that is relevant to the damage to be assessed, implying that damage analysis is coupled with structural analysis. It is shown that utilization of this additional information provides more accurate damage prediction. The difference between the two approaches is studied by comparison of results of damage estimation performed for a 2-D structural model of a reinforced-concrete frame. The results show that difference between uncoupled and coupled damage analysis estimates could be significant and that it depends on specific characteristics of the chosen structural model and the damage model in a complex way, preventing the possibility of estimating this error in a general form that is applicable to all practically possible cases. Damage estimation is performed for various damage models that include both single and multiple damage states. Since the final goal of seismic performance evaluation is estimation of decision variables such as repair cost, downtime, etc., the two approaches to damage estimation are also compared in terms of repair cost that is calculated for the reinforced-concrete frame. A case where structural damage prediction is based on observation of EDP alone, without a structural model available, is also studied. It is shown that incorporating site-specific information can significantly change the damage estimates and, therefore, may be worth doing

Looking Back to See Forward: The Use of Historic Repair Records to Inform Preventive Conservation Planning

This thesis examines how historic records of repairs can inform service life estimations and preventive conservation planning for historic structures. After a discussion of service life and preventive conservation, this thesis extracted and analyzed historic mentions of repairs in the record books of the Concord School House in Germantown, Philadelphia, Pennsylvania, which span from 1775 to 1987. Repairs to the building’s masonry, carpentry, windows, finishes, and roof assemblies were chosen for investigation. Data collected included the length of time between repairs and the recorded prices of repairs. The prices of repairs were converted into 2013 dollars and used as an indicator of the size of repairs and a means of comparison between repairs in different time periods. Ultimately, this thesis found that data from historic records of repairs was not specific enough to stand alone in estimating service lives of the building systems for use in preventive conservation planning. However, analysis of the historic records identified repair cycles which, when supplemented with conditions assessments, could be used to inform preventive conservation planning and the formation of building reinvestment plans. Investigation of historic repair records also revealed the importance of long-term, consistent care in preserving historic structures, and the need to conceptualize repair plans in terms of centuries rather than human lifespans

Data efficient deep learning for medical image analysis: A survey

The rapid evolution of deep learning has significantly advanced the field of medical image analysis. However, despite these achievements, the further enhancement of deep learning models for medical image analysis faces a significant challenge due to the scarcity of large, well-annotated datasets. To address this issue, recent years have witnessed a growing emphasis on the development of data-efficient deep learning methods. This paper conducts a thorough review of data-efficient deep learning methods for medical image analysis. To this end, we categorize these methods based on the level of supervision they rely on, encompassing categories such as no supervision, inexact supervision, incomplete supervision, inaccurate supervision, and only limited supervision. We further divide these categories into finer subcategories. For example, we categorize inexact supervision into multiple instance learning and learning with weak annotations. Similarly, we categorize incomplete supervision into semi-supervised learning, active learning, and domain-adaptive learning and so on. Furthermore, we systematically summarize commonly used datasets for data efficient deep learning in medical image analysis and investigate future research directions to conclude this survey.Comment: Under Revie

Study of fault-tolerant software technology

Presented is an overview of the current state of the art of fault-tolerant software and an analysis of quantitative techniques and models developed to assess its impact. It examines research efforts as well as experience gained from commercial application of these techniques. The paper also addresses the computer architecture and design implications on hardware, operating systems and programming languages (including Ada) of using fault-tolerant software in real-time aerospace applications. It concludes that fault-tolerant software has progressed beyond the pure research state. The paper also finds that, although not perfectly matched, newer architectural and language capabilities provide many of the notations and functions needed to effectively and efficiently implement software fault-tolerance