A Partial Taxonomy of Substitutability and Interchangeability

Substitutability, interchangeability and related concepts in Constraint Programming were introduced approximately twenty years ago and have given rise to considerable subsequent research. We survey this work, classify, and relate the different concepts, and indicate directions for future work, in particular with respect to making connections with research into symmetry breaking. This paper is a condensed version of a larger work in progress.Comment: 18 pages, The 10th International Workshop on Symmetry in Constraint Satisfaction Problems (SymCon'10

Substituabilité au voisinage pour le cadre WCSP

National audienceWCSP is an optimization problem for which many forms of soft local (arc) consistencies such as existential directional arc consistency (EDAC) and virtual arc consistency (VAC) have been proposed these last years. In this paper, we adopt a different perspective by revisiting the well-known property of (soft) substitutability. First, we provide a clear picture of the relationships existing between soft neighborhood substitutability (SNS) and a tractable property called $pcost$ which is based on the concept of overcost of values (through the use of so-called cost pairs). We prove that under certain assumptions, $pcost$ is equivalent to SNS but weaker than SNS in the general case since we show that SNS is coNP-hard. We also show that SNS preserves the property VAC but not the property EDAC. Finally, we introduce an optimized algorithm and we show on various series of WCSP instances, the practical interest of maintaining $pcost$ together with AC*, FDAC or EDAC, during search.WCSP est un problème d'optimisation pour lequel plusieurs formes de cohérences locales souples telles que, par exemple, la cohérence d'arc existentielle directionnelle (EDAC) et la cohérence d'arc virtuelle (VAC) ont été proposées durant ces dernières années. Dans cet article, nous adoptons une perspective différente en revisitant la propriété bien connue de la substituabilité (souple). Tout d'abord, nous précisons les relations existant entre la substituabilité de voisinage souple (SNS pour Soft Neighbourhood Substitutability) et une propriété appelée $pcost$ qui est basée sur le concept de surcoût de valeurs (par le biais de l'utilisation de paires de surcoût). Nous montrons que sous certaines hypothèses, $pcost$ est équivalent à SNS, mais que dans le cas général, elle est plus faible que SNS prouvée être coNP-difficile. Ensuite, nous montrons que SNS conserve la propriété VAC, mais pas la propriété EDAC. Enfin, nous introduisons un algorithme optimisé et nous montrons sur diverses séries d'instances WCSP l'intérêt pratique du maintien de $pcost$ avec AC*, FDAC ou EDAC, au cours de la recherche

Recommended techniques for effective maintainability. A continuous improvement initiative of the NASA Reliability and Maintainability Steering Committee

This manual presents a series of recommended techniques that can increase overall operational effectiveness of both flight and ground based NASA systems. It provides a set of tools that minimizes risk associated with: (1) restoring failed functions (both ground and flight based); (2) conducting complex and highly visible maintenance operations; and (3) sustaining a technical capability to support the NASA mission using aging equipment or facilities. It considers (1) program management - key elements of an effective maintainability effort; (2) design and development - techniques that have benefited previous programs; (3) analysis and test - quantitative and qualitative analysis processes and testing techniques; and (4) operations and operational design techniques that address NASA field experience. This document is a valuable resource for continuous improvement ideas in executing the systems development process in accordance with the NASA 'better, faster, smaller, and cheaper' goal without compromising safety

Use of Multivariate Techniques to Validate and Improved the Current USAF Pilot Candidate Selection Model

The Pilot Candidate Selection Method (PCSM) seeks to ensure the highest possible probability of success at UPT. PCSM applies regression weights to a candidate\u27s Air Force Officer Qualification Test (AFOQT) Pilot composite score, self-reported flying hours, and five Basic Attributes Test (BAT) score composites. PCSM scores range between 0 and 99 and is interpreted as a candidate\u27s probability of passing UPT. The goal of this study is to apply multivariate data analysis techniques to validate PCSM and determine appropriate changes to the model\u27s weights. Performance of the updated weights is compared to the current PCSM model via Receiver Operating Curves (ROC). In addition, two independent models are developed using multi-layer perceptron neural networks and discriminant analysis. Both linear and logistic regression is used to investigate possible updates to PCSM\u27s current linear regression weights. An independent test set is used to estimate the generalized performance of the regressions and independent models. Validation of the current PCSM model demonstrated in the first phase of this research is enhanced by the fact that PCSM outperforms all other models developed in the research

Managing extreme cryptocurrency volatility in algorithmic trading: EGARCH via genetic algorithms and neural networks.

Política de acceso abierto tomada de: https://www.aimspress.com/index/news/solo-detail/openaccesspolicyThe blockchain ecosystem has seen a huge growth since 2009, with the introduction of Bitcoin, driven by conceptual and algorithmic innovations, along with the emergence of numerous new cryptocurrencies. While significant attention has been devoted to established cryptocurrencies like Bitcoin and Ethereum, the continuous introduction of new tokens requires a nuanced examination. In this article, we contribute a comparative analysis encompassing deep learning and quantum methods within neural networks and genetic algorithms, incorporating the innovative integration of EGARCH (Exponential Generalized Autoregressive Conditional Heteroscedasticity) into these methodologies. In this study, we evaluated how well Neural Networks and Genetic Algorithms predict “buy” or “sell” decisions for different cryptocurrencies, using F1 score, Precision, and Recall as key metrics. Our findings underscored the Adaptive Genetic Algorithm with Fuzzy Logic as the most accurate and precise within genetic algorithms. Furthermore, neural network methods, particularly the Quantum Neural Network, demonstrated noteworthy accuracy. Importantly, the X2Y2 cryptocurrency consistently attained the highest accuracy levels in both methodologies, emphasizing its predictive strength. Beyond aiding in the selection of optimal trading methodologies, we introduced the potential of EGARCH integration to enhance predictive capabilities, offering valuable insights for reducing risks associated with investing in nascent cryptocurrencies amidst limited historical market data. This research provides insights for investors, regulators, and developers in the cryptocurrency market. Investors can utilize accurate predictions to optimize investment decisions, regulators may consider implementing guidelines to ensure fairness, and developers play a pivotal role in refining neural network models for enhanced analysis.This research was funded by the Universitat de Barcelona, under the grant UB-AE-AS017634

A Modular Open-Technology Device to Measure and Adjust Concentration of Sperm Samples for Cryopreservation

Repositories for aquatic germplasm can safeguard the genetic diversity of species of interest to aquaculture, research, and conservation. The development of such repositories is impeded by a lack of standardization both within laboratories and across the research community. Protocols for cryopreservation are often developed ad hoc and without close attention to variables, such as sperm concentration, that strongly affect the success and consistency of cryopreservation. The wide dissemination and use of specialized tools and devices can improve processing reliability, provide data logging, produce custom hardware to address unique problems, and save costs, time, and labor. The goal of the present work was to develop a low-cost and open-technology approach to standardize the concentration of sperm samples prior to cryopreservation. The specific objectives were to: 1) fabricate and test a peristaltic pump and optical evaluation module (POEM); 2) fabricate and test a prototype of the modular, open-technology concentration measurement and adjustment system (CMAS), which incorporated the POEM; 3) identify opportunities to extend the CMAS to microliter volumes through low-cost resin 3-D printing, and 4) identify strategies from this work that can be applied to future open fabrication efforts. The POEM and CMAS were prototyped and tested with biological samples. A relationship between optical signal and cell concentration of channel catfish (Ictalurus punctatus) sperm samples was established by linear regression. In a blind trial, cell concentrations were estimated with the POEM and correlated closely to their known concentrations (linear regression R2 = 0.9945) in a range of 1 × 108 to 4 × 109 cells/mL. The CMAS was able to estimate and adjust the concentration of a sample of the marine microalgae Tetraselmis chuii as a preparatory step for cryopreservation. To explore the possible use of the CMAS with microliter sample volumes in future work, evaluation of low-cost resin 3-D printing showed that this technology can approach conventional microfabrication techniques in feature quality and resolution. The development of the CMAS as open technology can provide opportunities for community-level standardization in cryopreservation of aquatic germplasm, invite new users, makers, and developers into the open-technology community, and increase the reach and capabilities of aquatic germplasm repositories

Advanced sensors technology survey

This project assesses the state-of-the-art in advanced or 'smart' sensors technology for NASA Life Sciences research applications with an emphasis on those sensors with potential applications on the space station freedom (SSF). The objectives are: (1) to conduct literature reviews on relevant advanced sensor technology; (2) to interview various scientists and engineers in industry, academia, and government who are knowledgeable on this topic; (3) to provide viewpoints and opinions regarding the potential applications of this technology on the SSF; and (4) to provide summary charts of relevant technologies and centers where these technologies are being developed

NASA/FAA helicopter simulator workshop

A workshop was convened by the FAA and NASA for the purpose of providing a forum at which leading designers, manufacturers, and users of helicopter simulators could initiate and participate in a development process that would facilitate the formulation of qualification standards by the regulatory agency. Formal papers were presented, special topics were discussed in breakout sessions, and a draft FAA advisory circular defining specifications for helicopter simulators was presented and discussed. A working group of volunteers was formed to work with the National Simulator Program Office to develop a final version of the circular. The workshop attracted 90 individuals from a constituency of simulator manufacturers, training organizations, the military, civil regulators, research scientists, and five foreign countries

Revealing and analyzing the shared structure of deep face embeddings

2022 Summer.Includes bibliographical references.Deep convolutional neural networks trained for face recognition are found to output face embeddings which share a fundamental structure. More specifically, one face verification model's embeddings (i.e. last--layer activations) can be compared directly to another model's embeddings after only a rotation or linear transformation, with little performance penalty. If only rotation is required to convert the bulk of embeddings between models, there is a strong sense in which those models are learning the same thing. In the most recent experiments, the structural similarity (and dissimilarity) of face embeddings is analyzed as a means of understanding face recognition bias. Bias has been identified in many face recognition models, often analyzed using distance measures between pairs of faces. By representing groups of faces as groups, and comparing them as groups, this shared embedding structure can be further understood. Specifically, demographic-specific subspaces are represented as points on a Grassmann manifold. Across 10 models, the geodesic distances between those points are expressive of demographic differences. By comparing how different groups of people are represented in the structure of embedding space, and how those structures vary with model designs, a new perspective on both representational similarity and face recognition bias is offered

Optimizing The Clinical Efficacy And Safety Of Biological Medicines And Their Biosimilars Within Available Resources In Europe

Introduction: Biological medicines contain active principles made by large and complex molecular structures, produced or extracted from a biological source. Biosimilars offer significant opportunities to reduce the price of biological medicines especially in an area of spiralling healthcare expenditure. Given the complexity of these medicines, their role in the management of many diseases, and their high price, there is the need to promote their appropriate use and develop tools and policies to increase access to high quality and affordable medicines. Aims: With a multidisciplinary approach, I took into account different facets this topic. 1. Analysis of the development and marketing authorisation of biosimilars in the EU to explore how the regulatory framework affects biosimilar clinical development, policies and uptake. 2. Analysis of the evidence supporting the switch between originator and biosimilars and the switch among biosimilars, in chronic clinical conditions. 3. Development and testing of an innovative analytical technique to monitor the appropriate use of biological medicines in order to maximise patient outcomes. 4. Development of education and training programmes for healthcare professionals regarding biological medicines and biosimilars in collaboration with local health authorities. Methods: I applied a combination of different methodologies, tailored to each different aim. 1. Analysis of pivotal clinical trials of EU approved biosimilars that compare their efficacy and safety to originators. 2. Series of systematic reviews that evaluate efficacy and safety of switching between biologics and their biosimilars of insulin analogues and anti-TNFs. Identification of studies through systematic searches on Medline, EMBASE, and The Cochrane Library. Update of anti-TNFs review (2022) to retrieve studies on switching among biosimilars. 3. Measurement of serum concentrations of therapeutic antibodies and anti-drug antibodies using the innovative Surface Plasmon Resonance-based immunoassay. 4. Definition of training objectives and modalities of educational sessions on biological medicines. Identification of clinical areas where these medicines are commonly used. Development of key metrics of prescription performance used as starting point for the course content. Main results: 1. Up to April 2022, I retrieved 68 biosimilars approved in the EU, corresponding to 18 active principles. The comparability exercise and subsequent approval of the majority of them is based on one or more pivotal phase III trials comparing their clinical efficacy to the originators. Often trials adopted an equivalence design, while insulin analogue biosimilars approval based on non-inferiority trial design. Two third of these trials included data on immunogenicity. The requirement for showing similarity in terms of clinical efficacy and safety provides a robust demonstration of comparable clinical outcomes. 2. I retrieved 22 studies addressing the insulin review questions. Three randomised controlled trials, on insulin glargine, collected evidence on equivalent efficacy, safety and immunogenicity when switching to biosimilar. Data on switching between different analogues, or from analogues to human insulins are very limited (one RCT). Studies comparing switching from originators to biosimilars of anti-TNF (infliximab, adalimumab, etanercept) in chronic inflammatory diseases are many and consistent. I included 32 records, corresponding to three systematic reviews, 14RCTs, 8 OLEs and three cohort studies. Substantial amount of evidence from RCTs is available for IFX and ADMB, versus one RCT of ETN. All these studies suggest switching is safe and effective. With regards of switching among biosimilars, I included 19 clinical studies: 11 cohort studies and 8 single-arm studies: none of these studies highlights significant concerns on switching between biosimilars. 3. The study involved 76 patients receiving infliximab for IBD. Concentration of biological drug and anti-drug-antibodies in each sample determined by SPR in triplicate by two researchers with different experience. Measurements with both ELISA and SPR indicated very similar IFX serum concentrations, with differences of ADA. All the sera showing ADA by ELISA also showed ADA by SPR. 8 patients showed ADA only with SPR: these ADA had significantly faster dissociation rate constants than those detectable by both methods. Measurement of IFX and ADA can support informed decisions for a more rational management of biological therapies. 4. Education programme was replied four times with 30-40 participants each. There was a case-mix of specialties: gastroenterologists, dermatologists, rheumatologists but also oncologists, internal medicine physicians and general practitioners. The majority was confident in prescribing biosimilars in naïve patients, with some restraint to switching. All the participants were in favour of better integration of the gained experience with different specialities. Conclusions: Altogether, the different strategies exploited in my project could support a clinical decision-making based on a more rational use of biological medicines, with benefits for both the patient’s outcome and the health budgets