scholarly journals Learning distributions as they come: Particle filter models for online distributional learning of phonetic categories

2018 ◽  
Author(s):  
Dave F Kleinschmidt
Keyword(s):  
Particle Filter ◽  
Computational Models ◽  
Ad Hoc ◽  
Cluster Structure ◽  
Proof Of Concept ◽  
Rational Model ◽  
Human Infants ◽  
Filter Model ◽  
Rational Models ◽  
Distributional Learning

Human infants have the remarkable ability to learn any human language. One proposed mechanism for this ability is distributional learning, where learners infer the underlying cluster structure from unlabeled input. Computational models of distributional learning have historically been principled but psychologically-implausible computational-level models, or ad hoc but psychologically plausible algorithmic-level models. Approximate rational models like particle filters can potentially bridge this divide, and allow principled, but psychologically plausible models of distributional learning to be specified and evaluated. As a proof of concept, I evaluate one such particle filter model, applied to learning English voicing categories from distributions of voice-onset times (VOTs). I find that this model learns well, but behaves somewhat differently from the standard, unconstrained Gibbs sampler implementation of the underlying rational model.

scholarly journals Robust simulation of mineral precipitation–dissolution problems with variable mineral surface area

2021 ◽  
Vol 129 (1) ◽  
Author(s):  
Serge Kräutle ◽  
Jan Hodai ◽  
Peter Knabner
Keyword(s):  
Surface Area ◽  
Ad Hoc ◽  
Chemical Species ◽  
Special Focus ◽  
Proof Of Concept ◽  
Mineral Surface ◽  
Mineral Precipitation ◽  
Numerical Tests ◽  
Ill Posed ◽  
Mineral Surface Area

AbstractWe consider a macroscale model of transport and reaction of chemical species in a porous medium with a special focus on mineral precipitation–dissolution processes. In the literature, it is frequently proposed that the reaction rate should depend on the reactive mineral surface area, and so on the amount of mineral. We point out that a frequently used model is ill posed in the sense that it admits non-unique solutions. We investigate what consequences this non-uniqueness has on the numerical solution of the model. The main novelty in this article is our proposal of a certain substitution which removes the ill-posedness from the system and which leads to better numerical results than some “ad hoc methods.” We think that the proposed substitution is a rather elegant way to get rid of the non-uniqueness and the numerical difficulties and is much less technical than other ideas. As a proof of concept, we present some numerical tests and simulations for the new model.

scholarly journals How to Validate in silico Deployment of Coronary Stents: Strategies and Limitations in the Choice of Comparator

2021 ◽  
Vol 3 ◽  
Author(s):  
Francesca Berti ◽  
Luca Antonini ◽  
Gianluca Poletti ◽  
Constantino Fiuza ◽  
Ted J. Vaughan ◽  
...  
Keyword(s):  
Numerical Model ◽  
Medical Devices ◽  
In Silico ◽  
Computational Models ◽  
Ad Hoc ◽  
Coronary Stent ◽  
Controlled Environment ◽  
Stent Deployment ◽  
Validation Plan ◽  
3D Printed

This study aims at proposing and discussing useful indications to all those who need to validate a numerical model of coronary stent deployment. The proof of the reliability of a numerical model is becoming of paramount importance in the era of in silico trials. Recently, the ASME V&V Standard Committee for medical devices prepared the V&V 40 standard document that provides a framework that guides users in establishing and assessing the relevance and adequacy of verification and validation activities performed for proving the credibility of models. To the knowledge of the authors, only a few examples of the application of the V&V 40 framework to medical devices are available in the literature, but none about stents. Specifically, in this study, the authors wish to emphasize the choice of a relevant set of experimental activities to provide data for the validation of computational models aiming to predict coronary stent deployment. Attention is focused on the use of ad hoc 3D-printed mock vessels in the validation plan, which could allow evaluating aspects of clinical relevance in a representative but controlled environment.

scholarly journals AODV-UI Proof of Concept on MIPS-based Wireless Router

2014 ◽  
Vol 10 (1) ◽  
pp. 14
Author(s):  
B. Anantasatya Adhi ◽  
Ruki Harwahyu ◽  
Abdusy Syarif ◽  
Harris Simaremare ◽  
R. Fitri Sari ◽  
...  
Keyword(s):  
Routing Protocol ◽  
Network Performance ◽  
Ad Hoc ◽  
Delivery Ratio ◽  
Proof Of Concept ◽  
Mobile Nodes ◽  
Media Access ◽  
Wireless Router ◽  
Hardware Configuration ◽  
Aodv Routing Protocol

AODV routing protocol facilitates changing and simple-to-setup network environment. It helps setting up a network without sufficient infrastructure, such as in disaster area. Development of AODV protocol has gathered a worldwide research interest. However, not many researches implement AODV routing protocol in real mobile nodes and real MANET. In addition, real implementation deals with other works concerning underlying protocol, firmware and hardware configuration, as well as detailed topology both in logical and physical arrangement. This work aims to implements Ad-hoc On-demand Distant Vector – particularly University of Indonesia AODV (AODV-UI) routing protocol on low-end inexpensive generic wireless routers as a proof of concept. AODV-UI is an improved version of AODV routing protocol that implements gateway interconnection and reverse route capability. This routing protocol has been previously successfully tested in NS-2. In this work, current AODV-UI protocol is ported to OpenWRT + MIPS (Microprocessor without Interlocked Pipeline Stages) little endian architecture then tested on the real networking environment. Underlying media access layer is also altered to provide the protocol greater control over the network. Performance of this implementation is measured in terms of energy consumption, routing overhead, end-to-end delay, protocol reliability and packet delivery ratio.

scholarly journals Προσαρμοστική επιδημική διάδοση σε ασύρματα αδόμητα δίκτυα

2018 ◽  
Author(s):  
Θεοφάνης Κοντός
Keyword(s):  
Quality Of Service ◽  
Ad Hoc ◽  
Proof Of Concept ◽  
One Stage ◽  
Look Ahead ◽  
Cross Layering

Το αντικείμενο της έρευνας αυτής είναι η επιδημική διάδοση (epidemic dissemination)πληροφορίας σε ασύρματα αδόμητα (ad hoc) δίκτυα με προσαρμοστικό τρόπο. Στό-χοι είναι η συμφιλίωση των απαιτήσεων για ευρεία διάδοση της πληροφορίας και γιαμειωμένο ενεργειακό κόστος, η εκτίμηση μιας βέλτιστης λύσης του προβλήματος αλ-λά και η επίτευξη της βέλτιστης απόδοσης στους εν λόγω τομείς με υψηλής ποιότηταςπληροφορία.Η προσαρμοστική επιδημική διάδοση (Π.Ε.Δ.) σε αδόμητα δίκτυα σε θορυβώδες περι-βάλλον είναι πρόβλημα με πολλές παραμέτρους.Με τη χρήση της διαστρωμάτωσης (cross-layering) με βάση την επίγνωση κατάστασηςκαναλιού μπορούν να κατασκευαστούν σχήματα προσαρμοστικής διάδοσης, τα οποίαεξοικονομούν ενέργεια διατηρώντας ταχεία και αποτελεσματική διάχυση πληροφορίαςή μόλυνση του δικτύου, σύμφωνα με την ορολογία της επιδημικής διάδοσης [1].Αυτού του είδους η αντιμετώπιση [1] είναι αναδραστική. Μπορεί όμως να σχεδιαστείμια εκδοχή σχημάτων με πρόβλεψη η οποία χρησιμοποιεί συναρτήσεις οφέλους για τηνπροσαρμογή των χαρακτηριστικών εκπομπής. Η προτεινόμενη λύση είναι μια απόδει-ξη της αρχής λειτουργίας (proof of concept, PoC) αυτής της ιδέας. Με την αντιμετώπισηαυτή εξοικονομείται ενέργεια ενώ και η διάχυση πληροφορίας είναι επιτυχής [2].Το πιο πάνω σχήμα μπορεί να ενισχυθεί με τη χρήση βελτιστοποίησης. Ελέγχονταςποια προσαρμογή είναι η πλέον σύμφορη σε κάθε χρονική στιγμή όπως στο [2], επι-τυγχάνεται μια έστω και «μυωπική» ορατότητα στο άμεσο μέλλον. Με τη χρήση τηςθεωρίας βέλτιστης παύσης (β.π.) μπορεί να αποκτηθεί καλύτερη ορατότητα σε βάθοςχρόνου και να προσεγγιστεί η βελτιστοποίηση. Η πραγματική βελτιστοποίηση εξαρτά-ται από την ικανοποίηση συνθηκών β.π. Αν αυτές δεν ικανοποιούνται πλήρως, τότεκαι οι αποκτώμενες λύσεις δεν είναι κατ’ ανάγκη βέλτιστες. Αυτό φαίνεται στην [3] μετη χρήση του κανόνα β.π. (one-stage-look-ahead, 1sla). Μπορεί να επιτευχθεί βελτί-ωση σε σχέση με μη προσαρμοστικές λύσεις ως προς την εξοικονόμηση ενέργειας. Ηευρεία μόλυνση του δικτύου εξακολουθεί να επιτυγχάνεται [3].Εξετάζεται στη συνέχεια ως πρόβλημα Π.Ε.Δ. ο χρονοπρογραμματισμός τακτικών εκ-πομπών. Η βελτιστοποίηση προσεγγίζεται με τη μετάβαση από αυστηρά περιοδικέςεκπομπές σε πλησιοπεριοδικό καθεστώς. Ο χρονοπρογραμματισμός πραγματοποιεί-ται με τη βοήθεια των ιδίων εργαλείων, δηλαδή διαστρωματικές συναρτήσεις οφέλουςκαι χρήση μηχανισμού β.π. Το πρόβλημα αυτό μοντελοποιείται ως κλασικό πρόβλημαγραμματέως, στο οποίο η χρήση β.π. προσφέρει βελτιστοποίηση. Σε σχέση με σχή-ματα χωρίς β.π. [2] και με μη προσαρμοστικά το σχήμα αυτό είναι αποδοτικότερο στηνεξοικονόμηση ενέργειας και επιτρέπει εξ ίσου επιτυχημένη μόλυνση του δικτύου. Είναιδυνατόν να συνυπολογιστεί και το ενεργειακό κόστος απόκτησης πληροφορίας κατά-στασης καναλιού (ΠΚΚ). Με τη βοήθεια αυτού του σχήματος, το δίκτυο συγκλίνει σεκατάσταση στην οποία το κόστος διάχυσης είναι σημαντικά ελαττωμένο ενώ σημαντικόποσοστό του εναπομένοντος κόστους οφείλεται στην ανάκτηση ΠΚΚ ([4]). Οι ακριβείςσυσχετισμοί εξαρτώνται από τις παραμέτρους του προβλήματος [4].Περαιτέρω θίγεται η δυνατότητα βελτίωσης της ποιότητας πληροφορίας με την αξιο-ποίηση σχημάτων σαν αυτό της [4]. Αρχικά θεωρείται ως ποιότητα η νεότητα της δια-χεόμενης πληροφορίας. Προτείνεται προσαρμογή των χαρακτηριστικών εκπομπής μεβάση τη νεότητα της μολύνουσας πληροφορίας με στόχο τη βελτίωση της μέσης ηλικί-ας της μολύνουσας τους κόμβους πληροφορίας. Με τον τρόπο αυτό εισάγεται η ιδέατης προσαρμογής των χαρακτηριστικών εκπομπής με βάση το περιεχόμενο της ίδιαςτης φερόμενης πληροφορίας.Ο μετριασμός των ευρυεκπομπών κατά τη φάση ανακάλυψης μονοπατιού στα πρω-τόκολλα δρομολόγησης είναι ένας ακόμη ελκυστικός στόχος και αντιμετωπίζεται σταπλαίσια του πρωτοκόλλου AODV. Εδώ αναδεικνύεται ο ανταγωνισμός μεταξύ εξοικο-νόμησης ενεργειακού κόστους και ταχείας εύρεσης πληροφορίας δρομολόγησης. Σεμια απόπειρα επέκτασης της τεχνικής στην εκπομπή της ίδιας της δρομολογούμενηςπληροφορίας (των δεδομένων δηλαδή), μεταπίπτουμε σε περιβάλλον μονοεκπομπών(unicast). Εδώ, ο μετριασμός εκπομπών μπορεί να έχει σοβαρές συνέπειες στη μετά-δοση πληροφορίας και καταδεικνύεται η ανάγκη εξέτασης του προβλήματος με τη βο-ήθεια μετρικών που εκφράζουν την έννοια της ποιότητας υπηρεσίας (quality of service,QoS) και κατ’ επέκταση της ποιότητας της πληροφορίας.Το εξεταζόμενο πρόβλημα χρονοπρογραμματισμού με την πρόσθετη νέα απαίτησηςτης βελτίωσης της ποιότητας πληροφορίας μπορεί να διατυπωθεί αυστηρά ως πρό-βλημα βέλτιστης παύσης με πεπερασμένο γνωστό ορίζοντα.Η ποιότητα πληροφορίας μπορεί να ορίζεται με βάση ιδιότητές της (όπως η νεότηταπου αναφέρθηκε) ή παραμέτρους του πρωτοκόλλου στα πλαίσια του οποίου γίνεται ηδιάχυσή της, όπως το TTL (time-to-live) στην περίπτωση του AODV.Έτσι η ποιότητα πληροφορίας αναδεικνύεται σε μια τρίτη συνιστώσα πέρα από το ε-νεργειακό κόστος και το ποσοστό μόλυνσης, η οποία λαμβάνει μέρος στον υπό εξέτασηαναδυόμενο ανταγωνισμό. Ανάλογα με την οριζόμενη ποιότητα πληροφορίας είναι δυ-νατή η εύρεση συμβιβασμού μεταξύ των τριών αυτών απαιτήσεων.

Graph analytics and visualization for cyber situational understanding

2021 ◽  
pp. 154851292110513
Author(s):  
Steven Noel ◽  
Stephen Purdy ◽  
Annie O’Rourke ◽  
Edward Overly ◽  
Brianna Chen ◽  
...  
Keyword(s):  
Natural Language ◽  
Detailed Analysis ◽  
Ad Hoc ◽  
Query Language ◽  
Software Components ◽  
Proof Of Concept ◽  
Graph Analytics ◽  
The Core ◽  
Interactive Visualizations ◽  
Graph Queries

This paper describes the Cyber Situational Understanding (Cyber SU) Proof of Concept (CySUP) software system for exploring advanced Cyber SU capabilities. CySUP distills complex interrelationships among cyberspace entities to provide the “so what” of cyber events for tactical operations. It combines a variety of software components to build an end-to-end pipeline for live data ingest that populates a graph knowledge base, with query-driven exploratory analysis and interactive visualizations. CySUP integrates with the core infrastructure environment supporting command posts to provide a cyber overlay onto a common operating picture oriented to tactical commanders. It also supports detailed analysis of cyberspace entities and relationships driven by ad hoc graph queries, including the conversion of natural language inquiries to formal query language. To help assess its Cyber SU capabilities, CySUP leverages automated cyber adversary emulation to carry out controlled cyberattack campaigns that impact elements of tactical missions.

Argument Structure Models and Visualization

2009 ◽  
pp. 75-82 ◽  
Author(s):  
Ephraim Nissan
Keyword(s):  
Artificial Intelligence ◽  
Argument Structure ◽  
Intelligent Systems ◽  
Computational Models ◽  
Ad Hoc ◽  
Wide Spectrum ◽  
Tutoring Systems ◽  
Computer Tools ◽  
Legal Evidence ◽  
Visualization Tools

In order to visualize argumentation, there exist tools from multimedia. The most advanced sides of computational modeling of arguments belong in models and tools upstream of visualization tools: the latter are an interface. Computer models of argumentation come in three categories: logic-based (highly theoretical), probablistic, and pragmatic ad hoc treatments. Theoretical formalisms of argumentation were developed by logicists within artificial intelligence (and were implemented and often can be reused outside the original applications), or then the formalisms are rooted in philosophers’ work. We cite some such work, but focus on tools that support argumentation visually. Argumentation turns out in a wide spectrum of everyday life situations, including professional ones. Computational models of argumentation have found application in tutoring systems, tools for marshalling legal evidence, and models of multiagent communication. Intelligent systems and other computer tools potentially stand to benefit as well. Multimedia are applied to argumentation (in visualization tools), and also are a promising field of application (in tutoring systems). The design of networks could potentially benefit, if communication is modeled using multiagent technology.

scholarly journals Reconfiguration of the Pontomedullary Respiratory Network: A Computational Modeling Study With Coordinated In Vivo Experiments

2008 ◽  
Vol 100 (4) ◽  
pp. 1770-1799 ◽  
Author(s):  
I. A. Rybak ◽  
R. O'Connor ◽  
A. Ross ◽  
N. A. Shevtsova ◽  
S. C. Nuding ◽  
...  
Keyword(s):  
Computational Models ◽  
Ad Hoc ◽  
Large Body ◽  
Network Activity ◽  
Respiratory Pattern ◽  
Respiratory Neurons ◽  
Phase Switching ◽  
In Vivo Experiments ◽  
Respiratory Network

A large body of data suggests that the pontine respiratory group (PRG) is involved in respiratory phase-switching and the reconfiguration of the brain stem respiratory network. However, connectivity between the PRG and ventral respiratory column (VRC) in computational models has been largely ad hoc. We developed a network model with PRG-VRC connectivity inferred from coordinated in vivo experiments. Neurons were modeled in the “integrate-and-fire” style; some neurons had pacemaker properties derived from the model of Breen et al. We recapitulated earlier modeling results, including reproduction of activity profiles of different respiratory neurons and motor outputs, and their changes under different conditions (vagotomy, pontine lesions, etc.). The model also reproduced characteristic changes in neuronal and motor patterns observed in vivo during fictive cough and during hypoxia in non-rapid eye movement sleep. Our simulations suggested possible mechanisms for respiratory pattern reorganization during these behaviors. The model predicted that network- and pacemaker-generated rhythms could be co-expressed during the transition from gasping to eupnea, producing a combined “burst-ramp” pattern of phrenic discharges. To test this prediction, phrenic activity and multiple single neuron spike trains were monitored in vagotomized, decerebrate, immobilized, thoracotomized, and artificially ventilated cats during hypoxia and recovery. In most experiments, phrenic discharge patterns during recovery from hypoxia were similar to those predicted by the model. We conclude that under certain conditions, e.g., during recovery from severe brain hypoxia, components of a distributed network activity present during eupnea can be co-expressed with gasp patterns generated by a distinct, functionally “simplified” mechanism.

scholarly journals Rational models of conditioning

2009 ◽  
Vol 32 (2) ◽  
pp. 204-205 ◽  
Author(s):  
Nick Chater
Keyword(s):  
Reinforcement Learning ◽  
Computational Models ◽  
Rational Models ◽  
Nonhuman Animals ◽  
High Level

AbstractMitchell et al. argue that conditioning phenomena may be better explained by high-level, rational processes, rather than by non-cognitive associative mechanisms. This commentary argues that this viewpoint is compatible with neuroscientific data, may extend to nonhuman animals, and casts computational models of reinforcement learning in a new light.

A Thrust-Vectored Submersible for Animal Behavior Research: Design and Proof of Concept

2010 ◽  
Author(s):  
Vladislav Kopman ◽  
Nicholas Cavaliere ◽  
Maurizio Porfiri
Keyword(s):  
Animal Behavior ◽  
Marine Mammals ◽  
Ad Hoc ◽  
Low Cost ◽  
Water Environment ◽  
Underwater Vehicle ◽  
Underwater Vehicles ◽  
Proof Of Concept ◽  
Safe Operation ◽  
Thrust Vectoring

In this paper, we present the design and proof of concept of a streamlined, low-cost, and smooth-hulled underwater vehicle (MASUV-1). MASUV-1 utilizes an ad-hoc designed multi-directional thrust-vectoring system for steering and an entirely enclosed propulsion system, allowing for safe operation in the vicinity of marine mammals. Tests of the vehicle in a still water environment show high maneuverability at speeds comparable with similar torpedo-type class underwater vehicles.

scholarly journals Shared Models and Open Infrastructures for the smart City Internet of Things based on the Semantic Web

2019 ◽  
Author(s):  
Mouad Banane ◽  
Abdessalam Belangour
Keyword(s):  
Semantic Web ◽  
Smart City ◽  
Ad Hoc ◽  
Smart Cities ◽  
Coordination Mechanism ◽  
Sensor Data ◽  
Proof Of Concept ◽  
Sensors And Actuators ◽  
Competition Control ◽  
The City

Contemporary cities face many challenges: energy, ecological, demographic or economic. To answer this, technological means are implemented in cities through the use of sensors and actuators. These cities are said to be smart. Currently, smart cities are operated by actors who share neither their sensor data nor access to their actuators. This situation is called vertical: each operator deploys its own sensors and actuators and has its own IT infrastructure hosting its applications. This leads to infrastructure redundancy and ad-hoc applications to oversee and control an area of the city. A trend is to move towards a so-called horizontal situation via the use of an open and shared mediation platform. Sensor data and access to the actuators are shared within this type of platform, allowing their sharing between the different actors. The costs of infrastructure and development are then reduced. This work is part of such a context of horizontalization, within an open and shared platform, in which we propose: 1) a layer of abstraction for control and supervision of the city, 2) a competition control mechanism handling conflict cases based on the RDF (Resource Description Framework) semantic Web standard, 3) a coordination mechanism promoting the reuse of actuators using ontology, 4) an implementation of our work by a proof of concept. The abstraction we propose is based on models from reactive systems. They aim to be generic and represent the invariant of the smart city: the physical elements. They allow applications to control and supervise the city. To facilitate the development of applications we standardize the interface of our models. Since these applications may have real-time constraints, especially those that have control objectives, we propose to take advantage of the distributed architecture of this type of platform. Given the sharing of the actuators, we have identified that conflicts can arise between applications. We propose a mechanism of competition control to deal with these cases of conflicts. We have also identified that a coordination mechanism must be offered to applications wishing to perform atomic control operations. Such a mechanism promotes the reuse of the actuators present in the city. Finally, we implemented our proposals around a proof of concept, including several use cases, to demonstrate our work.

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