1,683,225 research outputs found

    Modelling a layer for real-time management of interactions in web based distance learning

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    In the last few years, the University of Aveiro, Portugal, has been offering several distance learning courses over the Web, using e-learning platforms. Experience showed that different editions of a same course, using the same contents and structure, and having similar target learners, had different success rates. What would be the reason for that? A hypothesis was considered: The level of success could be directly related with the remote follow-up of the learners’ participation in the courses; the best results usually occur when the follow-up is closer. The existing e-learning platforms offer and the standardization works being developed by organizations and consortiums like IMS (IMS Global Learning Consortium, Inc), ADL SCORM (Advanced Distributed Learning Sherable Content Object Reference Model), IEEE LTSC LOM (Institute of Electrical and Electronic Engineers Learning Technologies Standard Committee Learning Object Metadata), ARIADNE (ARIADNE Foundation for the European Knowledge Pool), AICC CMI (Aviation Industry CBT Committee Computer Managed Instruction), etc, don’t cover the course monitorization concerns mentioned. Those projects were focused on aspects like contents and its delivery in the context of the execution of the courses’ activities. This is even true in the SCORM project that doesn’t include any reference to the management of the e-learning processes. Recently, in the context of the IMS Global Consortium, a new project designated IMS LD (Learning Design) is under development, providing a framework for the description of learning units under a three level model. In the most recently defined level, the C level, some functionalities related to notifications were proposed, expressing similar concerns to the ones that triggered our research. However, the extent at which IMS LD takes the functionalities is, from our point of view, not complete. This article describes a proposal of a reference model and functionalities towards a specification of a layer for real-time management of user interactions on LMSs, and its possible integration with the ADL SCORM standard proposal. The paper includes a discussion of the management metadata model for the LMS sub-system and how the integration of the management module under SCORM may be achieved

    A Study over Registration Server System Simulation

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    This paper is a continuous study of the registration server system using a previous created real-time simulation application for my working product- T-Mobile Digits’ registration server system - an Enterprise-level solution ensembles Skype for Business, but with a sizable testing user pool. As a standard system design normally includes the hardware infrastructure, computational logics and its own assigned rules/configures, and as all the complex system, a well-set server structure is the kernel for no matter testing or commercial purpose. The challenges are real and crucial for both business success besides the concerns of access capability and security. It will begin with the discussion of the server-side architecture and the current functional workflows. However, the problematic project is facing stalling issues of the registration system whenever the automation tests deploys, or the pressure tests are happening. The project norms are based on my previous study, current study after architecture refactor and enterprise server function reporting tool: Splunk. I will create a new hypothesis of the mathematical model/formula towards the new architecture and will retrieve the most of simulation skeleton formed from last semester by introducing new variables and new model for the performance comparisons. This project will finalize the study from the last semester and evaluate the server performance under the new architecture. Also, I will try to explore and compare the performances before and after the structure level refactors in the server architecture design, which is in achieving to provide comparison to the system architects or other stakeholders and help them to explore the possible improvements of the current registration server system. The ultimate goal of the study remains the same: I am seeking opportunities to analyze over current problematic flows and achieving making betterments to the product and I expect to make theoretical suggestions to better for the current workflow and logic structure of the current registration server system so that the server would be more durable for automation tests and malicious attacks

    Inverter Design for SiC-based Electric Drive Systems with Optimal Redundant States Control of Space Vector Modulation

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    The need for inverters with ever increasing power density and efficiency has recently become the driving factor for research in various fields. Increasing the operating voltage of the whole drive system and utilizing newly developed SiC power switches can contribute towards this goal. Higher operating voltage allows the design of drives with lower current, which leads to lower copper losses in cables and machine, while SiC switches can drastically increase the inverter efficiency. Offshore renewable power generation, such as tidal power, is a typical application where the increase of operating voltage can be highly beneficial. The ongoing electrification of transportation calls also for high power electric powertrains with high power density,where SiC technology has key advantages.In the first part of the thesis, suitable control schemes for inverters in synchronous machine drive systems are derived. A properly designed Maximum Power Point Tracking algorithm for kite-based tidal power systems is presented. The speed and torque of this new tidal power generation system varies periodically and the inverter control needs to be able to handle this variable power profile. Experimental verification of the developed control is conducted on a 35 kVA laboratory emulator of the tidal power generation unit.Electric drives using multilevel inverters are studied afterwards. Multilevel inverters use multiple low-voltage-rated switches and can operate at higher voltage than standard two-level inverters. The Neutral Point Clamped (NPC) converter is a commonly used multilevel inverter topology for medium voltage machine drives. However, the voltage balancing of its dc-side capacitors and the complexity of its control are still issues that have not been effectively solved. A new method for the optimal utilization of the redundant states in Space Vector pulse-width-Modulation (SVM) is proposed in this thesis in order to control its dc-link voltages. Experimental verification on a 4-kV-rated prototype medium-voltage PMSM drive with 5-level NPC converters is conducted in order to validate the effectiveness of the proposed control technique.Low switching and conduction losses are typical characteristics of SiC switches that can be utilized to build inverters with high power density, due to the increased efficiency and smaller form-factor. Due to the above, SiC power modules have been particularly attractive for the automotive industry. The design approach of 2-level automotive inverters has been studied in this project. Moreover, a new design approach for the cooling system of automotive inverters has been developed in this thesis, which fine-tunes the inverter heatsink utilizing standard legislated test routines for electric vehicles. Multiple conjugate-heat-transfer (CHT) computation results showcase the iterative optimization procedure on a test-case 250 kW (450 A) automotive SiC inverter.Finally, the experimental testing of high power machine drives in order to verify the control and the hardware design is an important step of the development process. Thus, the performance of the prototype 450 A SiC 2-level inverter has been been experimentally validated in a power hardware-in-the-loop (P-HIL) set-up that emulates an automotive drive system. Several challenges have been addressed with respect to the accurate modelling of the motor and the control of the circulating power in the system. A new control technique utilizing the redundant states of the SVM has been developed for this set-up to effectively suppress the zero-sequence current to 3.3 % of the line current at rated power

    Neurostream: Scalable and Energy Efficient Deep Learning with Smart Memory Cubes

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    open4siHigh-performance computing systems are moving towards 2.5D and 3D memory hierarchies, based on High Bandwidth Memory (HBM) and Hybrid Memory Cube (HMC) to mitigate the main memory bottlenecks. This trend is also creating new opportunities to revisit near-memory computation. In this paper, we propose a flexible processor-in-memory (PIM) solution for scalable and energy-efficient execution of deep convolutional networks (ConvNets), one of the fastest-growing workloads for servers and high-end embedded systems. Our co-design approach consists of a network of Smart Memory Cubes (modular extensions to the standard HMC) each augmented with a many-core PIM platform called NeuroCluster. NeuroClusters have a modular design based on NeuroStream coprocessors (for Convolution-intensive computations) and general-purpose RISC-V cores. In addition, a DRAM-friendly tiling mechanism and a scalable computation paradigm are presented to efficiently harness this computational capability with a very low programming effort. NeuroCluster occupies only 8 percent of the total logic-base (LoB) die area in a standard HMC and achieves an average performance of 240 GFLOPS for complete execution of full-featured state-of-the-art (SoA) ConvNets within a power budget of 2.5 W. Overall 11 W is consumed in a single SMC device, with 22.5 GFLOPS/W energy-efficiency which is 3.5X better than the best GPU implementations in similar technologies. The minor increase in system-level power and the negligible area increase make our PIM system a cost-effective and energy efficient solution, easily scalable to 955 GFLOPS with a small network of just four SMCs.openAzarkhish, Erfan*; Rossi, Davide; Loi, Igor; Benini, LucaAzarkhish, Erfan*; Rossi, Davide; Loi, Igor; Benini, Luc

    Improving processes for implementing evidence-based practice in midwifery: Development of an eTool(KIT) for midwives

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    Evidence-based practice (EBP) is well-established as the gold standard for service delivery of quality healthcare around the world, yet there remains a significant gap between best available evidence and its everyday use in maternity services. The numerous benefits of EBP are therefore never realised and although a considerable body of knowledge has evolved on how to promote the uptake of new EBPs, little is known about midwives’ experience of implementing EBP or leading practice change projects in clinical areas. The aim of this study was to work collaboratively with midwives towards the co-development of an evidence implementation resource, designed to provide clear direction and support to midwives wanting to implement new EBPs in clinical areas. This led to the design of a blueprint for an eTool(KIT) for midwives, outlining a stepby- step approach to leading practice change projects in clinical areas. A qualitative approach to the study design was adopted and critical realism employed as the philosophical underpinning for this research inquiry. Seventeen Australian midwives consented to participate in either a focus group discussion or face-to-face interview, which were audio recorded, transcribed and combined with additional field notes to provide a collection of data that was analysed and reported. Three higher order codes were synthesised from the findings to make overall meaning of the factors that contribute to the adoption of EBP in midwifery: “It’s hard to overcome the resistance towards new EBP, midwives are passionate yet reticent towards leading practice change”, “Inter-disciplinary collaboration and organisations supportive of change are key to improving implementation processes for midwives”, and “ To lead practice change initiatives, midwives require knowledge of system-level change and a clear process for evidence implementation”. The findings revealed that although midwives are passionate iv about EBP, they express reticence towards leading practice change for numerous reasons. These reasons contribute to the inconsistent and sub-optimal use of EBP in Australian maternity services. As such, this study offers a pragmatic approach to organisational change and demonstrates the potential for midwives to be leader of evidence-based change and key stakeholders in all future practice change projects in Australian maternity services

    A logic for the stepwise development of reactive systems

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    D↓is a new dynamic logic combining regular modalities with the binder constructor typical of hybrid logic, which provides a smooth framework for the stepwise development of reactive systems. Actually, the logic is able to capture system properties at different levels of abstraction, from high-level safety and liveness requirements, to constructive specifications representing concrete processes. The paper discusses its semantics, given in terms of reachable transition systems with initial states, its expressive power and a proof system. The methodological framework is in debt to the landmark work of D.Sannella and A.Tarlecki, instantiating the generic concepts of constructor and abstractor implementations by standard operators on reactive components, e.g. relabelling and parallel composition, as constructors, and bisimulation for abstraction.This work was funded by ERDF European Regional Development Fund, through the COMPETE Programme, and by National Funds through FCT – Portuguese Foundation for Science and Technology – within projects POCI-01-0145-FEDER-016692 (DaLí – Dynamic logics for cyber-physical systems: towards contract based design) and UID/MAT/04106/2013 at CIDMA. Further support was given by the project SmartEGOV, NORTE-01-0145-FEDER000037, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the EFDR. The first author is also supported by a FCT individual grant SFRH/BPD/103004/201

    Mixed quantum-classical linear systems synthesis and quantum feedback control designs

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    This thesis makes some theoretical contributions towards mixed quantum feedback network synthesis, quantum optical realization of classical linear stochastic systems and quantum feedback control designs. A mixed quantum-classical feedback network is an interconnected system consisting of a quantum system and a classical system connected by interfaces that convert quantum signals to classical signal (using homodyne detectors), and vice versa (using electro-optic modulators). In the area of mixed quantum-classical feedback networks, we present a network synthesis theory, which provides a natural framework for analysis and design for mixed linear systems. Physical realizability conditions are derived for linear stochastic differential equations to ensure that mixed systems can correspond to physical systems. The mixed network synthesis theory developed based on physical realizability conditions shows that how a classical of mixed quantum-classical systems described by linear stochastic differential equations can be built as a interconnection of linear quantum systems and linear classical systems using quantum optical devices as well as electrical and electric devices. However, an important practical problem for the implementation of mixed quantum-classical systems is the relatively slow speed of classical parts implemented with standard electrical and electronic devices, since a mixed system will not work correctly unless the electronic processing of classical devices is fast enough. Therefore, another interesting work is to show how classical linear stochastic systems build using electrical and electric devices can be physically implemented using quantum optical components. A complete procedure is proposed for a stable quantum linear stochastic system realizing a given stable classical linear stochastic system. The thesis explains how it may be possible to realize certain measurement feedback loops fully at the quantum level. In the area of quantum feedback control design, two numerical procedures based on extended linear matrix inequality (LMI) approach are proposed to design a coherent quantum controller in this thesis. The extended synthesis linear matrix inequalities are, in addition to new analysis tools, less conservative in comparison to the conventional counterparts since the optimization variables related to the system parameters in extended LMIs are independent of the symmetric Lyapunov matrix. These features may be useful in the optimal design of quantum optical networks. Time delays are frequently encountered in linear quantum feedback control systems such as long transmission lines between quantum plants and linear controllers, which may have an effect on the performance of closed-loop plant controller systems. Therefore, this thesis investigates the problem of linear quantum measurement-based feedback control systems subject to feedback-loop time delay described by linear stochastic differential equations. Several numerical procedures are proposed to design classical controllers that make quantum measurement-based feedback control systems with time delay stable and also guarantee that their desired control performance specifications are satisfied

    Convergence and interoperability of BIM with passive design principles

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    The Passive House Planning Package (PHPP) is a parametric modelling spreadsheet for building energy performance designed initially for the certification of buildings that meet passivhaus and EnerPHit refurbishment standards. However there is also a growing use of PHPP as a design stage tool to test strategic options for new build, hybrid and refurbishment development projects. As passive design principles follow a fabric-first approach to achieve a whole-house energy performance, the concept design stages are critical to success as decisions are made regarding orientation and heat-loss parameters arising out of the building geometry. In this context, PHPP is a trusted calculation tool that is comprehensive in the scope of factors and variables included to make it one of the most scientifically superior tools available. Its practical value is reinforced from a series of comparative studies which have undertaken triangulation in design stage energy assessments and PHPP has proved to be more accurate and more cost effective in practice than other standard modelling tools and methodologies such as IES and SAP. Where building information modelling (BIM) is a combination of geometric or spatial data generally found within a 3D architectural model and a connected document management system (DMS), PHPP data has largely been limited to the latter as one of the main instances in architecture and design modeling with a bias towards non-geometric data. This has changed with the introduction of designPH as an add-on tool for SketchUp and the BIM enabling in the recent versions of SketchUp. The paper is a case study in the practical application of the designPH tool for two separate UK based domestic design projects; one new build and one refurbishment; and the practical issues of interoperability with PHPP and BIM enabled software. The case studies review (1) the potential benefits of improved accuracy and quality control that address the technical performance gap between ‘design’ and ‘as-built’ standards; (2) the requirements regarding data collection, specifically the level of definition / detail (LoD) of data needed to describe the geometry and attributes of the existing structure and input climate data; (3) the technical limitations around ICT and software skills. Recommendations are made on the value of a simplified and integrated BIM workflow to benefit passive design projects. Critically the projects explore BIM interoperability using the addition of an energy domain to the IFC schema based on the input requirements for PHPP to make it more compatible with 3D modelling packages and achieve better integration between mathematical / parametric modelling of the energy performance and the building geometry

    Compromising emissions from a high speed cryptographic embedded system

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    Specific hardware implementations of cryptographic algorithms have been subject to a number of “side channel” attacks of late. A side channel is any information bearing emission that results from the physical implementation of a cryptographic algorithm. Smartcard realisations have been shown to be particularly vulnerable to these attacks. Other more complex embedded cryptographic systems may also be vulnerable, and each new design needs to be tested. The vulnerability of a recently developed high speed cryptographic accelerator is examined. The purpose of this examination is not only to verify the integrity of the device, but also to allow its designers to make a determination of its level of conformance with any standard that they may wish to comply with. A number of attacks were reviewed initially and two were chosen for examination and implementation - Power Analysis and Electromagnetic Analysis. These particular attacks appeared to offer the greatest threat to this particular system. Experimental techniques were devised to implement these attacks and a simulation and micrcontroller emulation were setup to ensure these techniques were sound. Each experimental setup was successful in attacking the simulated data and the micrcontroller circuit. The significance of this was twofold in that it verified the integrity of the setup and proved that a real threat existed. However, the attacks on the cryptographic accelerator failed in all cases to reveal any significant information. Although this is considered a positive result, it does not prove the integrity of the device as it may be possible for an adversary with more resources to successfully attack the board. It does however increase the level of confidence in this particular product and acts as a stepping stone towards conformance of cryptographic standards. The experimental procedures developed can also be used by designers wishing to test the vulnerability of their own products to these attacks

    Metadata for describing learning scenarios under European Higher Education Area paradigm

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    In this paper we identify the requirements for creating formal descriptions of learning scenarios designed under the European Higher Education Area paradigm, using competences and learning activities as the basic pieces of the learning process, instead of contents and learning resources, pursuing personalization. Classical arrangements of content based courses are no longer enough to describe all the richness of this new learning process, where user profiles, competences and complex hierarchical itineraries need to be properly combined. We study the intersection with the current IMS Learning Design specification and the additional metadata required for describing such learning scenarios. This new approach involves the use of case based learning and collaborative learning in order to acquire and develop competences, following adaptive learning paths in two structured levels
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