scholarly journals Simple Input Disturbance Observer-Based Control: Case Studies

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Tomáš Polóni ◽  
Ilya Kolmanovsky ◽  
Boris Rohaľ-Ilkiv
Keyword(s):  
Case Studies ◽  
Disturbance Observer ◽  
Inverted Pendulum ◽  
Experimental System ◽  
Matching Condition ◽  
Control Performance ◽  
Aircraft Control ◽  
Input Disturbance ◽  
First Case

In this paper, the application of an input disturbance observer (IDO)-based control, based on a simple input observer previously proposed and used for engine control, is demonstrated in two case studies. The first case study is longitudinal aircraft control with unmodeled aerodynamic nonlinearities satisfying matching conditions. The second case study is the control of an inverted pendulum on a cart which corroborates the ease of integration of IDO-based control into more complex controllers in situations when the matching condition is not satisfied. Improved robustness is demonstrated on an experimental system including changing the pendulum weight which is shown to have no effect on the overall control performance. In both case studies, if the IDO is not applied, the control performance is poor and leads to unstable operation.

Investigating the potential of redundant manipulators in narrow channels

2020 ◽  
pp. 095440622096451
Author(s):  
Ashish Singla ◽  
Jyotindra Narayan ◽  
Himanshu Arora
Keyword(s):  
Case Studies ◽  
Fuzzy Inference ◽  
Redundant Manipulators ◽  
Redundancy Resolution ◽  
Inference System ◽  
Narrow Channels ◽  
First Case ◽  
Task Priority ◽  
Patient Side

In this paper, an attempt has been made to investigate the potential of redundant manipulators, while tracking trajectories in narrow channels. The behavior of redundant manipulators is important in many challenging applications like under-water welding in narrow tanks, checking the blockage in sewerage pipes, performing a laparoscopy operation etc. To demonstrate this snake-like behavior, redundancy resolution scheme is utilized using two different approaches. The first approach is based on the concept of task priority, where a given task is split and prioritize into several subtasks like singularity avoidance, obstacle avoidance, torque minimization, and position preference over orientation etc. The second approach is based on Adaptive Neuro Fuzzy Inference System (ANFIS), where the training is provided through given datasets and the results are back-propagated using augmentation of neural networks with fuzzy logics. Three case studies are considered in this work to demonstrate the redundancy resolution of serial manipulators. The first case study of 3-link manipulator is attempted with both the approaches, where the objective is to track the desired trajectory while avoiding multiple obstacles. The second case study of 7-link manipulator, tracking trajectory in a narrow channel, is investigated using the concept of task priority. The realistic application of minimum-invasive surgery (MIS) based trajectory tracking is considered as the third case study, which is attempted using ANFIS approach. The 5-link spatial redundant manipulator, also known as a patient-side manipulator being developed at CSIR-CSIO, Chandigarh is used to track the desired surgical cuts. Through the three case studies, it is well demonstrated that both the approaches are giving satisfactory results.

scholarly journals Systemic Design: Two Canadian Case Studies

2014 ◽  
Vol 7 (3) ◽  
Author(s):  
Alex Ryan ◽  
Mark Leung
Keyword(s):  
Resource Management ◽  
Case Studies ◽  
Systems Thinking ◽  
Management System ◽  
Design Thinking ◽  
Clean Energy ◽  
Resource Management System ◽  
First Case ◽  
Systemic Design

This paper introduces two novel applications of systemic design to facilitate a comparison of alternative methodologies that integrate systems thinking and design. In the first case study, systemic design helped the Procurement Department at the University of Toronto re-envision how public policy is implemented and how value is created in the broader university purchasing ecosystem. This resulted in an estimated $1.5 million in savings in the first year, and a rise in user retention rates from 40% to 99%. In the second case study, systemic design helped the clean energy and natural resources group within the Government of Alberta to design a more efficient and effective resource management system and shift the way that natural resource departments work together. This resulted in the formation of a standing systemic design team and contributed to the creation of an integrated resource management system. A comparative analysis of the two projects identifies a shared set of core principles for systemic design as well as areas of differentiation that reveal potential for learning across methodologies. Together, these case studies demonstrate the complementarity of systems thinking and design thinking, and show how they may be integrated to guide positive change within complex sociotechnical systems.

scholarly journals Using Model Performance to Assess the Representativeness of Data for Model Development and Calibration in Financial Institutions

Risks ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 204
Author(s):  
Chamay Kruger ◽  
Willem Daniel Schutte ◽  
Tanja Verster
Keyword(s):  
Case Studies ◽  
Model Development ◽  
Model Performance ◽  
Data Set ◽  
Pooled Data ◽  
External Data ◽  
First Case ◽  
Multivariate Prediction ◽  
Credit Data

This paper proposes a methodology that utilises model performance as a metric to assess the representativeness of external or pooled data when it is used by banks in regulatory model development and calibration. There is currently no formal methodology to assess representativeness. The paper provides a review of existing regulatory literature on the requirements of assessing representativeness and emphasises that both qualitative and quantitative aspects need to be considered. We present a novel methodology and apply it to two case studies. We compared our methodology with the Multivariate Prediction Accuracy Index. The first case study investigates whether a pooled data source from Global Credit Data (GCD) is representative when considering the enrichment of internal data with pooled data in the development of a regulatory loss given default (LGD) model. The second case study differs from the first by illustrating which other countries in the pooled data set could be representative when enriching internal data during the development of a LGD model. Using these case studies as examples, our proposed methodology provides users with a generalised framework to identify subsets of the external data that are representative of their Country’s or bank’s data, making the results general and universally applicable.

scholarly journals SABRE observations of Pi2 pulsations: case studies

1997 ◽  
Vol 15 (1) ◽  
pp. 40-53 ◽  
Author(s):  
E. G. Bradshaw ◽  
M. Lester
Keyword(s):  
Case Studies ◽  
Magnetic Activity ◽  
Auroral Zone ◽  
Field Of View ◽  
Ionospheric Currents ◽  
Pi2 Pulsation ◽  
First Case ◽  
Pi2 Pulsations ◽  
Generation Region

Abstract. The characteristics of substorm-associated Pi2 pulsations observed by the SABRE coherent radar system during three separate case studies are presented. The SABRE field of view is well positioned to observe the differences between the auroral zone pulsation signature and that observed at mid-latitudes. During the first case study the SABRE field of view is initially in the eastward electrojet, equatorward and to the west of the substorm-enhanced electrojet current. As the interval progresses, the western, upward field-aligned current of the substorm current wedge moves westward across the longitudes of the radar field of view. The westward motion of the wedge is apparent in the spatial and temporal signatures of the associated Pi2 pulsation spectra and polarisation sense. During the second case study, the complex field-aligned and ionospheric currents associated with the pulsation generation region move equatorward into the SABRE field of view and then poleward out of it again after the third pulsation in the series. The spectral content of the four pulsations during the interval indicate different auroral zone and mid-latitude signatures. The final case study is from a period of low magnetic activity when SABRE observes a Pi2 pulsation signature from regions equatorward of the enhanced substorm currents. There is an apparent mode change between the signature observed by SABRE in the ionosphere and that on the ground by magnetometers at latitudes slightly equatorward of the radar field of view. The observations are discussed in terms of published theories of the generation mechanisms for this type of pulsation. Different signatures are observed by SABRE depending on the level of magnetic activity and the position of the SABRE field of view relative to the pulsation generation region. A twin source model for Pi2 pulsation generation provides the clearest explanation of the signatures observed.

Mathematical Metaphors Gone Wild

2017 ◽  
Author(s):  
Roi Wagner
Keyword(s):  
Early Modern ◽  
Case Studies ◽  
Cognitive Theory ◽  
Early Modernity ◽  
First Case ◽  
Mathematical Life ◽  
George Lakoff

This chapter examines two case studies that illustrate the limitations of the cognitive theory of mathematical metaphor in accounting for the formation of actual historical mathematical life worlds. The first case study deals with four medieval and early modern examples of relating algebra to geometry. These examples show that when two mathematical domains are linked, what passes between them cannot be reduced to “inferences,” as assumed by the theory of mathematical metaphor. The second case study reviews notions of infinity since early modernity and demonstrates that these notions are far too variegated and complex to be subsumed under a single metaphor—namely, George Lakoff and Rafael Núñez's basic metaphor of infinity, which tries to read all mathematical infinities as metaphorically projecting final destinations on indefinite sequences.

Two Case Studies of Semiosis in Mathematics

2017 ◽  
Author(s):  
Roi Wagner
Keyword(s):  
Gender Role ◽  
Case Studies ◽  
Generating Functions ◽  
Stable Marriage ◽  
Mathematical Language ◽  
Stable Marriage Problem ◽  
Marriage Problem ◽  
First Case ◽  
Mathematical Signs

This chapter presents two case studies that highlight the problems of mathematical semiosis: how mathematical signs obtain and change their senses. The first case study follows the paradigmatic mathematical sign, x, as it is used in applications of powers series to combinatorics via generating functions. The second case study concerns gender role stereotypes involving the so-called “stable marriage problem.” Both case studies open up questions of how meaning is transferred within and across mathematical contexts and try to substantiate the book's claims about interpretation, formalization, and constraints over mathematical objects and statements. The chapter also considers gender-neutral mathematical language in the context of sexuality.

An Evaluation of a Test-Driven Security Risk Analysis Approach Based on Two Industrial Case Studies

2019 ◽  
pp. 69-103 ◽  
Author(s):  
Gencer Erdogan ◽  
Phu H. Nguyen ◽  
Fredrik Seehusen ◽  
Ketil Stølen ◽  
Jon Hofstad ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Case Studies ◽  
Risk Model ◽  
Case Study Research ◽  
Security Risk ◽  
Risk Models ◽  
First Case ◽  
Assessment Approach ◽  
Security Risk Assessment

Risk-driven testing and test-driven risk assessment are two strongly related approaches, though the latter is less explored. This chapter presents an evaluation of a test-driven security risk assessment approach to assess how useful testing is for validating and correcting security risk models. Based on the guidelines for case study research, two industrial case studies were analyzed: a multilingual financial web application and a mobile financial application. In both case studies, the testing yielded new information, which was not found in the risk assessment phase. In the first case study, new vulnerabilities were found that resulted in an update of the likelihood values of threat scenarios and risks in the risk model. New vulnerabilities were also identified and added to the risk model in the second case study. These updates led to more accurate risk models, which indicate that the testing was indeed useful for validating and correcting the risk models.

The design(ing) of language

2020 ◽  
pp. 69-85
Author(s):  
Grant Goodall
Keyword(s):  
Case Studies ◽  
Inflectional Morphology ◽  
Human Language ◽  
The Third ◽  
First Case ◽  
Design Property ◽  
The Creation ◽  
John Wilkins ◽  
Fundamental Design

Courses on invented languages can do much more than just introduce students to linguistics. Through three case studies, it is shown that as students learn how to design a language, they also learn about the design of human language in a way that is unlikely to occur in other courses. The first case study involves the creation of a lexicon, in relation to John Wilkins’ invented language of 1668 and to Saussurean arbitrariness, commonly regarded as a fundamental design property of human language. The second case study concerns phonemic inventories. By designing their own from scratch, students see the competing pressures that phonemic inventories must satisfy in all languages. The third case study concerns inflectional morphology and the pressures that determine the form of particular morphemes. All of these case studies are accessible to students and help them engage with important aspects of the design properties of human language.

Assessing the Usefulness of Testing for Validating and Correcting Security Risk Models Based on Two Industrial Case Studies

2016 ◽  
pp. 1016-1037
Author(s):  
Gencer Erdogan ◽  
Fredrik Seehusen ◽  
Ketil Stølen ◽  
Jon Hofstad ◽  
Jan Øyvind Aagedal
Keyword(s):  
Risk Assessment ◽  
Case Studies ◽  
Web Application ◽  
Risk Model ◽  
Security Risk ◽  
Risk Models ◽  
First Case ◽  
New Information ◽  
Financial Application

The authors present the results of an evaluation in which the objective was to assess how useful testing is for validating and correcting security risk models. The evaluation is based on two industrial case studies. In the first case study the authors analyzed a multilingual financial Web application, while in the second case study they analyzed a mobile financial application. In both case studies, the testing yielded new information which was not found in the risk assessment phase. In particular, in the first case study, new vulnerabilities were found which resulted in an update of the likelihood values of threat scenarios and risks in the risk model. New vulnerabilities were also identified and added to the risk model in the second case study. These updates led to more accurate risk models, which indicate that the testing was indeed useful for validating and correcting the risk models.

Case Studies Using Program Evaluation to Drive Evidence-Based Practices

2018 ◽  
pp. 109-131
Author(s):  
Julie Q. Morrison ◽  
Anna L. Harms
Keyword(s):  
Early Literacy ◽  
Case Studies ◽  
Behavioral Interventions ◽  
Single Case ◽  
Pilot Project ◽  
Evidence Based Practices ◽  
First Case ◽  
Single Case Designs ◽  
The Cost

This chapter consists of three case studies that illustrate how the evaluation approaches, methods, techniques, and tools presented in Chapters 1 to 5 can be translated into practice. The first case study describes an evaluation of the Dyslexia Pilot Project, a statewide multi-tier system of supports (MTSS) initiative targeting early literacy. In this evaluation, special attention was paid to the evaluating the cost-effectiveness of serving students in kindergarten to grade 2 proactively. The second case study features the use of single-case designs and corresponding summary statistics to evaluate the collective impact of more than 500 academic and behavioral interventions provided within an MTSS framework as part of the annual statewide evaluation of the Ohio Internship Program in School Psychology. The third case study focuses on efforts to evaluate the fidelity of implementation for teacher teams’ use of a five-step process for data-based decision making and instructional planning.

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