Using lambda networks to enhance performance of interactive large simulations

The ability to use a visualisation tool to steer large simulations provides innovative and novel usage scenarios, e.g. the ability to use new algorithms for the computation of free energy profiles along a nanopore [1]. However, we find that the performance of interactive simulations is sensitive to the quality of service of the network with variable latency and packet loss in particular having a detrimental effect The use of dedicated networks (provisioned in this case as a circuit-switched point-to-point optical lightpath or lambda) can lead to significant (50% or more) performance enhancement, When funning on say 128 or 256 processors of a high-end supercomputer this saving has a significant value. We perform experiments to understand the impact of network characteristics on the performance of a large parallel classical molecular dynamics simulation when coupled interactively to a remote visualisation tool. This paper discusses the experiments performed and presents the results from the systematic studies. © 2006 IEEE.Published versio

Voltage Stability Assessment of Radial Distribution Systems Including Optimal Allocation of Distributed Generators

Assessment of power systems voltage stability is considered an important assignment for the operation and planning of power system. In this paper, a voltage stability study using Continuous Power Flow (CPF) is introduced to evaluate the impact of Distribution Generator (DG) on radial distribution systems. On the way to allocate the DG, a hybrid between the Voltage Stability Index (VSI) and Whale Optimization Algorithm (WOA) is developed. The main purpose of using VSI is to find the most sensitive buses for allocating the DG in the system. Hence, Fuzzy logic control with the Normalized VSI (NVSI) and the voltage magnitude at each bus are used to determine the candidate buses. However, the best DG size is calculated using WOA. Four standard radial distribution systems are used in this paper; 12, 33, 69, and 85-bus. The developed hybrid optimization method is compared with other existing analytical and metaheuristic optimization techniques to prove its efficiency. The results prove the ability of the developed method in the allocation of DG. In addition, the influence of the DG integration on enhancing the voltage stability through injecting the proper active and reactive powers is studied

Developing Student Model for Intelligent Tutoring System

The effectiveness of an e-learning environment mainly encompasses on how efficiently the tutor presents the learning content to the candidate based on their learning capability. It is therefore inevitable for the teaching community to understand the learning style of their students and to cater for the needs of their students. One such system that can cater to the needs of the students is the Intelligent Tutoring System (ITS). To overcome the challenges faced by the teachers and to cater to the needs of their students, e-learning experts in recent times have focused in Intelligent Tutoring System (ITS). There is sufficient literature that suggested that meaningful, constructive and adaptive feedback is the essential feature of ITSs, and it is such feedback that helps students achieve strong learning gains. At the same time, in an ITS, it is the student model that plays a main role in planning the training path, supplying feedback information to the pedagogical module of the system. Added to it, the student model is the preliminary component, which stores the information to the specific individual learner. In this study, Multiple-choice questions (MCQs) was administered to capture the student ability with respect to three levels of difficulty, namely, low, medium and high in Physics domain to train the neural network. Further, neural network and psychometric analysis were used for understanding the student characteristic and determining the student’s classification with respect to their ability. Thus, this study focused on developing a student model by using the Multiple-Choice Questions (MCQ) for integrating it with an ITS by applying the neural network and psychometric analysis. The findings of this research showed that even though the linear regression between real test scores and that of the Final exam scores were marginally weak (37%), still the success of the student classification to the extent of 80 percent (79.8%) makes this student model a good fit for clustering students in groups according to their common characteristics. This finding is in line with that of the findings discussed in the literature review of this study. Further, the outcome of this research is most likely to generate a new dimension for cluster based student modelling approaches for an online learning environment that uses aptitude tests (MCQ’s) for learners using ITS. The use of psychometric analysis and neural network for student classification makes this study unique towards the development of a new student model for ITS in supporting online learning. Therefore, the student model developed in this study seems to be a good model fit for all those who wish to infuse aptitude test based student modelling approach in an ITS system for an online learning environment. (Abstract by Author

The Impact of Integrating Computer Simulations On The Achievement of Grade 11 Emirati Students In Uniform Circular Motion

Education has been affected by the advancement of technology, especially computer software. This thesis focuses on the impact of computer simulations on students’ acquisition of Physics concepts related to the topic of Uniform Circular Motion. The main purpose of this thesis is to examine to what extent can computer simulations help students of grade 11 from Al Ain, United Arab Emirates (UAE), learn factual, conceptual and procedural knowledge related to Uniform Circular Motion. It also aims to investigate how simulations affect students of different abilities in terms of their achievement in Physics. A quazi- experimental method was used, where participants were divided into an experimental group and a control group. The experimental group was taught using computer simulations, and the control group was instructed with the help of real- life videos and animations. The main instrument was an achievement test administered before and after the intervention. The study showed a statistically significant advantage for the experimental group over the control group, especially in the procedural knowledge dimension. In addition, results showed that students of medium and low academic levels benefit from the simulations more than students of high level. Results drawn from this study provide valuable information on effective integration of technology in physics teaching, because it examines the impact of simulations on different knowledge dimensions, as well as their effect on students of different abilities. As a result, it encompasses a large spectrum of variables in terms of the effectiveness of simulations, giving room for further researches on technology integration in science education in the UAE and the Arab world context

Does Model Uncertainty Lead to Less Central Bank Transparency?

This paper discusses the problem of monetary policy transparency in a simple static robust control framework. In this framework, we identify two sources of monetary policy uncertainty. First, we identify the uncertainty about the central bank’s inflation stabilization preferences, which affects the private sector’s inflation expectations and therefore the realized inflation and output. On the other hand, uncertainty means that central bank is unsure about its model, in the sense that there is a group of approximate models that it also considers as possibly true and its objective is to choose a rule that will work under a range of different model specifications. We find that robustness reveals the emergence of a precautionary behaviour of the central bank in the case of unstructured model uncertainty, reducing thus central bank’s willingness to choice a high degree of monetary policy transparency.central bank transparency, min-max policies, model uncertainty, robust control.

Application and Optimization of Contact-Guided Replica Exchange Molecular Dynamics

Proteine sind komplexe Makromoleküle, die in lebenden Organismen eine große Vielfalt an wichtigen Aufgaben erfüllen. Proteine können beispielsweise Gene regulieren, Struktur stabilisieren, Zellsignale übertragen, Substanzen transportieren und vieles mehr. Typischerweise sind umfassende Kenntnisse von Struktur und Dynamik eines Proteins erforderlich um dessen physiologische Funktion und Interaktionsmechanismen vollständig zu verstehen. Gewonnene Erkenntnisse sind für Biowissenschaften unerlässlich und können auf viele Bereiche angewendet werden, wie z.B. für Arzneimitteldesign oder zur Krankheitsbehandlung. Trotz des unfassbaren Fortschritts experimenteller Techniken bleibt die Bestimmung einer Proteinstruktur immer noch eine herausfordernde Aufgabe. Außerdem können Experimente nur Teilinformationen liefern und Messdaten können mehrdeutig und schwer zu interpretieren sein. Aus diesem Grund werden häufig Computersimulationen durchgeführt um weitere Erkenntnisse zu liefern und die Lücke zwischen Theorie und Experiment zu schließen. Heute sind viele in-silico Methoden in der Lage genaue Protein Strukturmodelle zu erzeugen, sei es mit einem de novo Ansatz oder durch Verbesserung eines anfänglichen Modells unter Berücksichtigung experimenteller Daten. In dieser Dissertation erforsche ich die Möglichkeiten von Replica Exchange Molekulardynamik (REX MD) als ein physikbasierter Ansatz zur Erzeugung von physikalisch sinnvollen Proteinstrukturen. Dabei lege ich den Fokus darauf möglichst nativähnliche Strukturen zu erhalten und untersuche die Stärken und Schwächen der angewendeten Methode. Ich erweitere die Standardanwendung, indem ich ein kontaktbasiertes Bias-Potential integriere um die Leistung und das Endergebnis von REX zu verbessern. Die Einbeziehung nativer Kontaktpaare, die sowohl aus theoretischen als auch aus experimentellen Quellen abgeleitet werden können, treibt die Simulation in Richtung gewünschter Konformationen und reduziert dementsprechend den notwendigen Rechenaufwand. Während meiner Arbeit führte ich mehrere Studien durch mit dem Ziel, die Anreicherung von nativ-ähnlichen Strukturen zu maximieren, wodurch der End-to-End Prozess von geleitetem REX MD optimiert wird. Jede Studie zielt darauf ab wichtige Aspekte der verwendeten Methode zu untersuchen und zu verbessern: 1) Ich studiere die Auswirkungen verschiedener Auswahlen von Bias-Kontakten, insbesondere die Reichweitenabhängigkeit und den negativen Einfluss von fehlerhaften Kontakten. Dadurch kann ich ermitteln, welche Art von Bias zu einer signifikanten Anreicherung von nativ-ähnlichen Konformationen führen im Vergleich zu regulärem REX. 2) Ich führe eine Parameteroptimierung am verwendeten Bias-Potential durch. Der Vergleich von Ergebnissen aus REX-Simulationen unter Verwendung unterschiedlicher sigmoidförmiger Potentiale weist mir sinnvolle Parameter Bereiche auf, wodurch ich ein ideales Bias-Potenzial für den allgemeinen Anwendungsfall ableiten kann. 3) Ich stelle eine de novo Faltungsmethode vor, die möglichst schnell viele einzigartige Startstrukturen für REX generieren kann. Dabei untersuche ich ausführlich die Leistung dieser Methode und vergleiche zwei verschiedene Ansätze zur Auswahl der Startstruktur. Das Ergebnis von REX wird stark verbessert, falls Strukturen bereits zu Beginn eine große Bandbreite des Konformationsraumes abdecken und gleichzeitig eine geringe Distanz zum angestrebten Zustand aufweisen. 4) Ich untersuche vier komplexe Algorithmusketten, die in der Lage sind repräsentative Strukturen aus großen biomolekularen Ensembles zu extrahieren, welche durch REX erzeugt wurden. Dabei studiere ich ihre Robustheit und Zuverlässigkeit, vergleiche sie miteinander und bewerte ihre erbrachte Leistung numerisch. 5) Basierend auf meiner Erfahrung mit geleitetem REX MD habe ich ein Python-Paket entwickelt um REX-Projekte zu automatisieren und zu vereinfachen. Es ermöglicht einem Benutzer das Entwerfen, Ausführen, Analysieren und Visualisieren eines REX-Projektes in einer interaktiven und benutzerfreundlichen Umgebung

Open research issues on multi-models for complex technological systems

Abstract -We are going to report here about state of the art works on multi-models for complex technological systems both from the theoretical and practical point of view. A variety of algorithmic approaches (k-mean, dss, etc.) and applicative domains (wind farms, neurological diseases, etc.) are reported to illustrate the extension of the research area