Topological derivatives via one-sided derivative of parametrized minima and minimax

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Michel C. Delfour
Keyword(s):  
Directional Derivative ◽  
Topological Derivative ◽  
Dimensional Euclidean Space ◽  
Objective Functions ◽  
State Equations ◽  
Content Type ◽  
Adjoint State ◽  
Topological Derivatives ◽  
Wide Range ◽  
The One

PurposeThe object of the paper is to illustrate how to obtain the topological derivative as a semidifferential in a general and practical mathematical setting for d-dimensional perturbations of a bounded open domain in the n-dimensional Euclidean space.Design/methodology/approachThe underlying methodology uses mathematical notions and powerful tools with ready to check assumptions and ready to use formulas via theorems on the one-sided derivative of parametrized minima and minimax.FindingsThe theory and the examples indicate that the methodology applies to a wide range of problems: (1) compliance and (2) state constrained objective functions where the coupled state/adjoint state equations appear without a posteriori substitution of the adjoint state.Research limitations/implicationsDirect approach that considerably simplifies the analysis and computations.Originality/valueIt was known that the shape derivative was a differential. But the topological derivative is only a semidifferential, that is, a one-sided directional derivative, which is not linear with respect to the direction, and the directions are d-dimensional bounded measures.

scholarly journals An introduction to the topological derivative

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Samuel Amstutz
Keyword(s):  
Simple Model ◽  
Design Methodology ◽  
Topological Derivative ◽  
Modern Approach ◽  
Content Type ◽  
Adjoint State ◽  
Topological Derivatives ◽  
State Technique ◽  
Didactic Presentation

PurposeThis paper provides a self-contained introduction to the mathematical aspects of the topological derivative.Design/methodology/approachFull justifications are given on simple model problems following a modern approach based on the averaged adjoint state technique. Extensions are discussed in relation with the literature on the field.FindingsClosed expressions of topological derivatives are obtained and commented.Originality/valueSeveral cases are covered in a unified and didactic presentation. Some elements of proof are novel.

scholarly journals Exploring conflicts between stakeholders in tourism industry. Citizen attitude toward peer-to-peer accommodation platforms

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
José María Martín Martín ◽  
Juan F. Prados-Castillo ◽  
Mónica de Castro-Pardo ◽  
Juan De Dios Jimenez Aguilera
Keyword(s):  
Rural Areas ◽  
Disease Transmission ◽  
Exploratory Study ◽  
Peer To Peer ◽  
Tourism Industry ◽  
Content Type ◽  
Wide Range ◽  
Depth Analysis ◽  
Negative Impacts ◽  
The One

Purpose The expansion of online platforms for renting tourist accommodations has given rise to a great deal of controversy in society. Likewise, the arrival of tourists in residential settings has led to a wide range of positive and negative impacts, resulting in conflicts between different stakeholders. The purpose of this paper is to analyze whether there is variation in the perception of the impacts associated with peer-to-peer accommodation platforms among different stakeholders? Additionally, it also seeks to investigate what kind of impacts generate the highest level of conflict among stakeholders? Design/methodology/approach Given the relative novelty of the problem, this paper proposes an exploratory study that sheds light on some of the main issues with the purpose of supporting further research in the future. The aim is to analyze which impacts are perceived as more positive or negative by each group and to create indexes of conflict for these groups regarding their perception of the impacts. This study is based on fieldwork carried out in April 2020, which consists of 600 online surveys of local residents in the city of Granada. This city, one of Spain’s main tourist spots, suffers the highest tourist pressure in the country. Findings The exploratory study suggests that the greatest consensus is generated in the assessment of economic impacts, either negative or positive. The greatest conflicts are related to the assessment of the effect of this activity on housing preservation. The group comprising accommodation owners of tourist flats is the one that shows a more dissenting opinion from the rest, confronting especially the group formed by citizens whose income depends on tourism. Originality/value There is a lack of studies on the perception of tourism impacts associated with online tourism rental platforms. This is the first study to analyze both, how the main stakeholders associated with this activity assess the different impacts derived from this form of tourist accommodation as a whole and the conflicts derived from such an assessment. An additional innovation is that the analysis investigates the potential fear of disease transmission caused by tourists. It would be interesting to continue this research by applying the same questionnaire in different environments, such as rural areas or societies with different structures from the one analyzed here. Likewise, future in-depth analysis of some of the conflicts is recommended so as to ascertain their origin.

Adaptive arm motion generation of humanoid robot operating in dynamic environments

2014 ◽  
Vol 41 (2) ◽  
pp. 124-134 ◽  
Author(s):  
Zulkifli Mohamed ◽  
Mitsuki Kitani ◽  
Genci Capi
Keyword(s):  
Humanoid Robot ◽  
Dynamic Environments ◽  
Robot Motion ◽  
Robot Arm ◽  
Objective Functions ◽  
Motion Generation ◽  
Content Type ◽  
Neural Controllers ◽  
Wide Range ◽  
Arm Motion

Purpose – The purpose of this paper is to compare the performance of the robot arm motion generated by neural controllers in simulated and real robot experiments. Design/methodology/approach – The arm motion generation is formulated as an optimization problem. The neural controllers generate the robot arm motion in dynamic environments optimizing three different objective functions; minimum execution time, minimum distance and minimum acceleration. In addition, the robot motion generation in the presence of obstacles is also considered. Findings – The robot is able to adapt its arm motion generation based on the specific task, reaching the goal position in simulated and experimental tests. The same neural controller can be employed to generate the robot motion for a wide range of initial and goal positions. Research limitations/implications – The motion generated yield good results in both simulation and experimental environments. Practical implications – The robot motion is generated based on three different objective functions that are simultaneously optimized. Therefore, the humanoid robot can perform a wide range of tasks in real-life environments, by selecting the appropriate motion. Originality/value – A new method for adaptive arm motion generation of a mobile humanoid robot operating in dynamic human and industrial environments.

Do different political connections affect firms' distress risk differently?

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Thang Xuan Nguyen ◽  
Khanh Hoang ◽  
Cuong Cao Nguyen ◽  
Thang Ngoc Bach
Keyword(s):  
Financial Distress ◽  
Sample Selection ◽  
Political Connections ◽  
Political Connection ◽  
Content Type ◽  
Distress Risk ◽  
Test Specifications ◽  
Increased Risk ◽  
Wide Range ◽  
The One

PurposeThis paper investigates how different types of corporate political connection, including government-linked investment (GLI), former officials as politically-connected directors (PCD), cronyism (CRO) and government leaders' family ties (FAM), influence financial distress risk in Malaysian firms.Design/methodology/approachWe separate political connections into four distinct categories and investigate their relationship with firm distress risk and compare the results with the one-size-fits-all treatment which is popular in the literature. We apply a battery of sensitivity test to ensure that our inferences are robust to a wide range of test specifications, endogeneity concern and sample selection methods.FindingsThe empirical results show that the effect of political connections on distress risk is strongly heterogeneous. GLI and PCD firms tend to have higher distress risk via increased risk-taking behaviors because of the different incentives of the connections, while this nexus does not directly exhibit in CRO and FAM firms. Further analyses reveal that CRO and FAM firms are more likely to venture into risky international diversification, thus indirectly amplifying their distress risk.Originality/valueOur findings are novel and provide practical implications for financial analysts, investors and portfolio managers operating in the capital markets.

Preserved autoregulation in the rhesus spinal cord after high cervical cord section

1976 ◽  
Vol 44 (4) ◽  
pp. 425-428 ◽  
Author(s):  
Arthur I. Kobrine ◽  
Thomas F. Doyle ◽  
Norwyn Newby ◽  
Hugo V. Rizzoli
Keyword(s):  
Spinal Cord ◽  
Cervical Cord ◽  
Spinal Cord Blood Flow ◽  
Thoracic Spinal Cord ◽  
Content Type ◽  
Thoracic Spinal ◽  
Wide Range ◽  
Blood Pressures ◽  
The One ◽  
High Cervical

✓ The authors studied the effect of high cervical cord section on the phenomenon of autoregulation in the rhesus monkey with the hydrogen clearance method to measure focal spinal cord blood flow (SCBF). Laminectomies were performed at T7–11 and C1–2. The spinal cord was completely severed at C1–2. Under normocapnic conditions, SCBF was then measured in the thoracic spinal cord over a wide range of blood pressures (MAP). The MAP was either lowered by bleeding or raised by the intravenous infusion of angiotensin. Autoregulation was found to be intact between 50 and 125 mm Hg, following a pattern similar to the one observed in the intact animal.

General Trend of Negative Transference Number in Li Salt/Ionic Liquid Mixtures

2019 ◽  
Author(s):  
Nicola Molinari ◽  
Jonathan P. Mailoa ◽  
Boris Kozinsky
Keyword(s):  
Ionic Liquid ◽  
Transference Number ◽  
Liquid Mixtures ◽  
Single Linkage ◽  
Self Diffusion ◽  
Wide Range ◽  
Single Linkage Cluster ◽  
Concentrated Solution ◽  
The One ◽  
Dynamics Simulations

We show that strong cation-anion interactions in a wide range of lithium-salt/ionic liquid mixtures result in a negative lithium transference number, using molecular dynamics simulations and rigorous concentrated solution theory. This behavior fundamentally deviates from the one obtained using self-diffusion coefficient analysis and agrees well with experimental electrophoretic NMR measurements, which accounts for ion correlations. We extend these findings to several ionic liquid compositions. We investigate the degree of spatial ionic coordination employing single-linkage cluster analysis, unveiling asymmetrical anion-cation clusters. Additionally, we formulate a way to compute the effective lithium charge that corresponds to and agrees well with electrophoretic measurements and show that lithium effectively carries a negative charge in a remarkably wide range of chemistries and concentrations. The generality of our observation has significant implications for the energy storage community, emphasizing the need to reconsider the potential of these systems as next generation battery electrolytes.<br>

How Phillips saw the light

2020 ◽  
Vol 36 (8) ◽  
pp. 29-31
Keyword(s):  
Design Methodology ◽  
Reading Time ◽  
Daily Basis ◽  
Business World ◽  
Content Type ◽  
Freak Show ◽  
The World ◽  
Pertinent Information ◽  
The One ◽  
Practical Implications

Purpose Reviews the latest management developments across the globe and pinpoints practical implications from cutting-edge research and case studies. Design/methodology/approach This briefing is prepared by an independent writer who adds their own impartial comments and places the articles in context. Findings The problem with developing a reputation of being something of an oracle in the business world is that all of a sudden, everyone expects you to pull off the trick of interpreting the future on a daily basis. Like a freak show circus act or one-hit wonder pop singer, people expect you to perform when they see you, and they expect you to perform the thing that made you famous, even if it is the one thing in the world you don’t want to do. And when you fail to deliver on these heightened expectations, you are dismissed as a one trick pony, however good that trick is in the first place. Originality/value The briefing saves busy executives and researchers hours of reading time by selecting only the very best, most pertinent information and presenting it in a condensed and easy-to-digest format.

PROMETHEE-based ranking of project managers based on the five personality traits

Kybernetes ◽  
2019 ◽  
Vol 49 (4) ◽  
pp. 1083-1102
Author(s):  
Georgios N. Aretoulis ◽  
Jason Papathanasiou ◽  
Fani Antoniou
Keyword(s):  
Personality Traits ◽  
Questionnaire Survey ◽  
Multicriteria Decision Making ◽  
Project Managers ◽  
Preference Ranking ◽  
Infrastructure Projects ◽  
Public Infrastructure ◽  
Content Type ◽  
The One ◽  
Selection Of

Purpose This paper aims to rank and identify the most efficient project managers (PMs) based on personality traits, using Preference Ranking Organization METHod for Enrichment Evaluations (PROMETHEE) methodology. Design/methodology/approach The proposed methodology relies on the five personality traits. These were used as the selection criteria. A questionnaire survey among 82 experienced engineers was used to estimate the required weights per personality trait. A second two-part questionnaire survey aimed at recording the PMs profile and assess the performance of personality traits per PM. PMs with the most years of experience are selected to be ranked through Visual PROMETHEE. Findings The findings suggest that a competent PM is the one that scores low on the “Neuroticism” trait and high especially on the “Conscientiousness” trait. Research limitations/implications The research applied a psychometric test specifically designed for Greek people. Furthermore, the proposed methodology is based on the personality characteristics to rank the PMs and does not consider the technical skills. Furthermore, the type of project is not considered in the process of ranking PMs. Practical implications The findings could contribute in the selection of the best PM that maximizes the project team’s performance. Social implications Improved project team communication and collaboration leading to improved project performance through better communication and collaboration. This is an additional benefit for the society, especially in the delivery of public infrastructure projects. A lot of public infrastructure projects deviate largely as far as cost and schedule is concerned and this is an additional burden for public and society. Proper project management through efficient PMs would save people’s money and time. Originality/value Identification of the best PMbased on a combination of multicriteria decision-making and psychometric tests, which focus on personality traits.

scholarly journals Transfer of Plasmid DNA to Clinical Coagulase-Negative Staphylococcal Pathogens by Using a Unique Bacteriophage

2015 ◽  
Vol 81 (7) ◽  
pp. 2481-2488 ◽  
Author(s):  
Volker Winstel ◽  
Petra Kühner ◽  
Bernhard Krismer ◽  
Andreas Peschel ◽  
Holger Rohde
Keyword(s):  
Plasmid Dna ◽  
Genetic Manipulation ◽  
Current Knowledge ◽  
Virulence Determinants ◽  
Coagulase Negative Staphylococci ◽  
Reliable Technique ◽  
Content Type ◽  
Research Activities ◽  
Wide Range ◽  
Genetic Barriers

ABSTRACTGenetic manipulation of emerging bacterial pathogens, such as coagulase-negative staphylococci (CoNS), is a major hurdle in clinical and basic microbiological research. Strong genetic barriers, such as restriction modification systems or clustered regularly interspaced short palindromic repeats (CRISPR), usually interfere with available techniques for DNA transformation and therefore complicate manipulation of CoNS or render it impossible. Thus, current knowledge of pathogenicity and virulence determinants of CoNS is very limited. Here, a rapid, efficient, and highly reliable technique is presented to transfer plasmid DNA essential for genetic engineering to important CoNS pathogens from a uniqueStaphylococcus aureusstrain via a specificS. aureusbacteriophage, Φ187. Even strains refractory to electroporation can be transduced by this technique once donor and recipient strains share similar Φ187 receptor properties. As a proof of principle, this technique was used to delete the alternative transcription factor sigma B (SigB) via allelic replacement in nasal and clinicalStaphylococcus epidermidisisolates at high efficiencies. The described approach will allow the genetic manipulation of a wide range of CoNS pathogens and might inspire research activities to manipulate other important pathogens in a similar fashion.

scholarly journals Use of Proteins Identified through a Functional Genomic Screen To Develop a Protein Subunit Vaccine That Provides Significant Protection against Virulent Streptococcus suis in Pigs

2017 ◽  
Vol 86 (3) ◽  
Author(s):  
Susan L. Brockmeier ◽  
Crystal L. Loving ◽  
Tracy L. Nicholson ◽  
Jinhong Wang ◽  
Sarah E. Peters ◽  
...  
Keyword(s):  
Immune Response ◽  
Vaccine Trial ◽  
Streptococcus Suis ◽  
Protein Subunit ◽  
Content Type ◽  
Degree Of Protection ◽  
Wide Range ◽  
Associated Proteins ◽  
Clinical Protection ◽  
Cellular Immune

ABSTRACT Streptococcus suis is a bacterium that is commonly carried in the respiratory tract and that is also one of the most important invasive pathogens of swine, commonly causing meningitis, arthritis, and septicemia. Due to the existence of many serotypes and a wide range of immune evasion capabilities, efficacious vaccines are not readily available. The selection of S. suis protein candidates for inclusion in a vaccine was accomplished by identifying fitness genes through a functional genomics screen and selecting conserved predicted surface-associated proteins. Five candidate proteins were selected for evaluation in a vaccine trial and administered both intranasally and intramuscularly with one of two different adjuvant formulations. Clinical protection was evaluated by subsequent intranasal challenge with virulent S. suis . While subunit vaccination with the S. suis proteins induced IgG antibodies to each individual protein and a cellular immune response to the pool of proteins and provided substantial protection from challenge with virulent S. suis , the immune response elicited and the degree of protection were dependent on the parenteral adjuvant given. Subunit vaccination induced IgG reactive against different S. suis serotypes, indicating a potential for cross protection.

Sign in / Sign up

Export Citation Format

Share Document