Showing papers on "Modular design published in 2014"

Large-scale modular quantum-computer architecture with atomic memory and photonic interconnects

Abstract: The practical construction of scalable quantum-computer hardware capable of executing nontrivial quantum algorithms will require the juxtaposition of different types of quantum systems. We analyze a modular ion trap quantum-computer architecture with a hierarchy of interactions that can scale to very large numbers of qubits. Local entangling quantum gates between qubit memories within a single register are accomplished using natural interactions between the qubits, and entanglement between separate registers is completed via a probabilistic photonic interface between qubits in different registers, even over large distances. We show that this architecture can be made fault tolerant, and demonstrate its viability for fault-tolerant execution of modest size quantum circuits.

UQLab: a framework for uncertainty quantification in MATLAB

Abstract: Uncertainty quantification is a rapidly growing field in computer simulation-based scientific applications. The UQLAB project aims at the development of a MATLABbased software framework for uncertainty quantification. It is designed to encourage both academic researchers and field engineers to use and develop advanced and innovative algorithms for uncertainty quantification, possibly exploiting modern distributed computing facilities. Ease of use, extendibility and handling of non-intrusive stochastic methods are core elements of its development philosophy. The modular platform comprises a highly optimized core probabilistic modelling engine and a simple programming interface that provides unified access to heterogeneous high performance computing resources. Finally, it provides a content-management system that allows users to easily develop additional custom modules within the framework. In this contribution, we intend to demonstrate the features of the platform at its current development stage.

On Energy Storage Requirements in Modular Multilevel Converters

Abstract: The modular multilevel converter is a promising topology for high-voltage and high-power applications. By using submodules equipped with dc-capacitors excellent output voltage waveforms can be obtained at low switching frequencies. The rated energy storage of the submodule capacitors is a driving factor of the size, cost, and weight of the submodules. Although the modular multilevel converter has been thoroughly investigated in the literature, a more detailed analysis of the energy-storage requirements will provide an important contribution for dimensioning and analysis of modular multilevel converters. Such an analysis is presented in this paper. The analysis relates the power transfer capability to the stored energy in the converter and the findings are validated by both simulations and experimental results. The required size of the submodule capacitors in a 4.5 MW grid-connected converter is first calculated and the calculated operating range is then compared with simulation results. The experimental results show that if the average capacitor voltage is allowed to increase 10% above the nominal value an energy storage to power transfer ratio of 21 J/kW can be achieved. It is concluded that the presented theory can relate the power transfer capability to the energy storage in the converter and is thus a valuable tool in the design and analysis of modular multilevel converters.

A Control Method for Voltage Balancing in Modular Multilevel Converters

Abstract: The modular multilevel converter (MMC) is attractive for medium- or high-power applications because of the advantages of its high modularity, availability, and high power quality. The voltage balancing of the floating capacitors in the cascaded submodules of the MMC is a key issue. In this paper, a voltage-balancing control method is proposed. This method uses the phase-shifted carrier-based pulsewidth modulation scheme to control high-frequency current components for capacitor voltage balancing in the MMC without measuring the arm currents. Simulations and experimental studies of the MMC were conducted, and the results confirm the effectiveness of the proposed capacitor voltage-balancing control method.

Hierarchical Block Structures and High-resolution Model Selection in Large Networks

Abstract: Social, technological, and biological networks are known to organize into modules or ``communities.'' Characterizing and identifying modules is highly nontrivial and still an outstanding problem in networks research. A new approach uses both the concept of modular hierarchy for network construction and the methods of statistical inference to address this problem, succeeding where the existing approaches see difficulties.

Modular Multilevel Converter Models for Electromagnetic Transients

Abstract: Modular multilevel converters (MMCs) may contain numerous insulated-gate bipolar transistors. The modeling of such converters for electromagnetic transient-type (EMT-type) simulations is complex. Detailed models used in MMC-HVDC simulations may require very large computing times. Simplified and averaged models have been proposed in the past to overcome this problem. In this paper, existing averaged and simplified models are improved in order to increase their range of applications. The models are compared and analyzed for different transient events on an MMC-HVDC system.

FAtiMA Modular: Towards an Agent Architecture with a Generic Appraisal Framework

Abstract: This paper presents a generic and flexible architecture for emotional agents, with what we consider to be the minimum set of functionalities that allows us to implement and compare different appraisal theories in a given scenario. FAtiMA Modular, the architecture proposed is composed of a core algorithm and by a set of components that add particular functionality (either in terms of appraisal or behaviour) to the architecture, which makes the architecture more flexible and easier to extend.

ChipWhisperer: An Open-Source Platform for Hardware Embedded Security Research

Abstract: This paper introduces a complete side channel analysis toolbox, inclusive of the analog capture hardware, target device, capture software, and analysis software. The highly modular design allows use of the hardware and software with a variety of existing systems. The hardware uses a synchronous capture method which greatly reduces the required sample rate, while also reducing the data storage requirement, and improving synchronization of traces. The synchronous nature of the hardware lends itself to fault injection, and a module to generate glitches of programmable width is also provided. The entire design (hardware and software) is open-source, and maintained in a publicly available repository. Several long example capture traces are provided for researchers looking to evaluate standard cryptographic implementations.

Identifying modular flows on multilayer networks reveals highly overlapping organization in social systems.

Abstract: Unveiling the community structure of networks is a powerful methodology to comprehend interconnected systems across the social and natural sciences. To identify different types of functional modules in interaction data aggregated in a single network layer, researchers have developed many powerful methods. For example, flow-based methods have proven useful for identifying modular dynamics in weighted and directed networks that capture constraints on flow in the systems they represent. However, many networked systems consist of agents or components that exhibit multiple layers of interactions. Inevitably, representing this intricate network of networks as a single aggregated network leads to information loss and may obscure the actual organization. Here we propose a method based on compression of network flows that can identify modular flows in non-aggregated multilayer networks. Our numerical experiments on synthetic networks show that the method can accurately identify modules that cannot be identified in aggregated networks or by analyzing the layers separately. We capitalize on our findings and reveal the community structure of two multilayer collaboration networks: scientists affiliated to the Pierre Auger Observatory and scientists publishing works on networks on the arXiv. Compared to conventional aggregated methods, the multilayer method reveals smaller modules with more overlap that better capture the actual organization.

Accurate Capacitor Voltage Ripple Estimation and Current Control Considerations for Grid-Connected Modular Multilevel Converters

Abstract: In this paper, the analytical solution for the submodule voltage ripple equations of a modular multilevel converter (MMC) is derived, based on the knowledge of the external voltage/current magnitudes, and enhancing a concept previously presented in the literature. In order to achieve high accuracy, all passive elements of the converter, common-mode voltage injection as well as intentionally imposed circulating current harmonics are taken into consideration. The natural charge level mechanism of the capacitor voltages is also explained. As application examples, the three- as well as the two-phase grid-connected MMC cases are chosen. The control of line and circulating currents is also discussed and two respective independent feedback loops are formed. The concept of fictive-axis emulation is tailored for the two-phase MMC case, in order to achieve vector control of the line current and therefore straightforward desired injection of active and reactive power. Finally, the development of a reduced-scale laboratory prototype is presented and a full set of experimental results are provided, verifying the aforementioned concepts.

IoT design space challenges: Circuits and systems

Abstract: The Internet of Things (IoT) is a rapidly emerging application space, poised to become the largest electronics market for the semiconductor industry. IoT devices are focused on sensing and actuating of our physical environment and have a nearly unlimited breadth of uses. In this paper, we explore the IoT application space and then identify two common challenges that exist across this space: ultra-low power operation and system design using modular, composable components. We survey recent low power techniques and discuss a low power bus that enables modular design. Finally, we conclude with three example ultra-low power, millimeter-scale IoT systems.

MODULAR: software for the autonomous computation of modularity in large network sets

Abstract: Many ecological systems can be represented as networks of interactions. A key feature in these networks is their organization into modules, which are subsets of tightly connected elements. We introduce MODULAR to perform rapid and autonomous calculation of modularity in network sets. MODULAR reads a set of files representing unipartite or bipartite networks, and identifies modules using two different modularity metrics widely used in the ecological networks literature. To estimate modularity, the software offers five optimization methods to the user. The software also includes two null models commonly used in studies of ecological networks to verify how the degree of modularity differs from two distinct theoretical benchmarks.

Supramolecular host–guest polymeric materials for biomedical applications

Abstract: The bottom–up synthesis of highly complex functional materials from simple modular blocks is an intriguing area of research. Driven by the chemistry of supramolecular assembly, modules which self-assemble into intricate structures have been described. These hierarchically assembled systems extend beyond the individual molecule and rely on non-covalent interactions in a directed self-assembly process. The intrinsic properties of the materials can be modified by exploiting the dynamic and specific uni-directional interactions among the building. This also allows the building of novel supramolecular structures such as hydrogels, micelles and vesicles. These aqueous supramolecular networks belong to a novel category of soft biomaterials exhibiting attractive properties such as stimuli-responsiveness and self-healing properties derived from their dynamic behavior. These are important for a wide variety of emerging applications. In this review, the latest literature describing the formation of dynamic polymeric networks through host–guest complex formation will be summarised. These approaches carried out in the aqueous medium have unlocked a versatile toolbox for the design and fine-tuning of supramolecular self-assembled materials.

Active balancing system for electric vehicles with incorporated low voltage bus

Abstract: Electric-drive vehicles, including hybrid (HEV), plug-in hybrid (PHEV) and electric vehicles (EV), require a high-voltage (HV) battery pack for propulsion, and a low-voltage (LV) dc bus for auxiliary loads. This paper presents an architecture that uses modular dc-dc bypass converters to perform active battery cell balancing and to supply current to auxiliary loads, eliminating the need for a separate HV-to-LV high step-down dc-dc converter. The modular architecture, which achieves continuous balancing of all cells, can be used with an arbitrary number of cells in series, requires no control communications between converters, and naturally shares the auxiliary load current according to the relative state-of-charge (SOC) and capacities of the battery cells. Design and control details are provided for low-voltage, low-power dual active bridge (DAB) power converters serving as bypass converter modules. Experimental results are presented for a system consisting of two series 3.6 Ah NMC battery cells and two DAB bypass converters, with combined outputs rated to supply a 12 V, 35 W auxiliary load.

Energy-balancing Control Strategy for Modular Multilevel Converters Under Submodule Fault Conditions

Abstract: The modular multilevel converter (MMC) is a newly introduced switch-mode converter topology with the potential for high-voltage and high-power applications This paper focuses on the design and control methods for fault-tolerant operation using redundant submodules (SMs), which is one of the most important features in the MMC topology By comparing three design schemes of redundant SMs, the most economic and reliable scheme is identified In addition, a mathematical model of the MMC with arms containing different numbers of SMs is developed Based on the identified scheme and mathematical model, an energy-balancing control strategy is proposed to keep the MMC operating normally under SM fault conditions Finally, time-domain simulations of a 61-level MMC system are performed, using the PSCAD/EMTDC software, while experiments are carried out on a 41-level MMC prototype The simulation and experimental results validate the design scheme, mathematical model, and proposed energy-balancing control strategy

Simplified Terminal Behavioral Model for a Modular Multilevel Converter

Abstract: Modular multilevel converters (MMCs) are emerging to be an attractive approach for high-power applications Equivalent circuit models and dynamic models for the MMC that provide a faithful representation of system behavior are quite complex given the large number of energy states and control variables They are not particularly useful in studying the terminal behavior of the converter and for the development of an intuitive control approach to regulate power transfer This paper reduces the complexity of the MMC analytical model to an equivalent boost-buck converter circuit while providing particularly insightful transparency of the converter's physical operation from a terminal perspective The transformed boost-buck converter model and control performance are verified using simulations and experiments using a laboratory scale prototype

Global Asymptotic Stability of Modular Multilevel Converters

Abstract: Modular multilevel converters require that the controller is designed so that the submodule capacitor voltages are equalized and stable, independent of the loading conditions. Assuming that the individual capacitor-voltage sharing is managed effectively, an open-loop strategy has been designed to ensure that the total amount of energy stored inside the converter always will be controlled. This strategy, using the steady-state solutions of the dynamic equations for controlling the total stored energy in each converter arm, has proven to be effective. The intention of this paper is to explain in a rigorous way the mechanism behind the suggested strategy and to prove that, when this open-loop strategy is used, the system becomes globally asymptotically stable. Experimental verification on a three-phase 10-kVA prototype is presented.

SimuLTE - A modular system-level simulator for LTE/LTE-A networks based on OMNeT++

Abstract: This paper describes SimuLTE, an open-source system-level simulator for LTE and LTE-Advanced (LTE-A) networks. SimuLTE is based on OMNeT++, a well-known, widely-used modular simulation framework, which offers a high degree of experiment support. As such, it can be seamlessly integrated with all the networkoriented modules of the OMNeT++ family, such as INET, thus enabling - among other things - credible simulation of end-to-end real-life applications across heterogeneous technologies. We describe the modeling choices and general architecture of the SimuLTE software, with particular emphasis on the MAC and scheduling functions, and show performance evaluation results obtained using the simulator.

Influence of Leading Design Parameters on the Force Performance of a Complementary and Modular Linear Flux-Switching Permanent-Magnet Motor

Abstract: This paper investigates the influence of some leading design parameters on the force performance of a new complementary and modular linear flux-switching permanent-magnet (LFSPM) motor. The originality of the proposed structure is that each phase consists of two “E”-shaped modules, whose positions are mutually 180 ° electrical degrees apart. Also, there is a flux barrier between the two modules. First, the structure and influence of some leading design parameters on the force performance of the complementary and modular LFSPM motor are analyzed. Then, a conventional LFSPM motor obtained directly from a rotary FSPM motor is optimized and compared with the complementary and modular LFSPM motor based on finite-element method. The results reveal that the proposed motor has sinusoidal and symmetrical three-phase back electromotive force waveforms and smaller cogging force and force ripple than the existing motors. Moreover, a prototype of the proposed motor is built to validate the study.

A Decentralized Controller Architecture for a Cascaded H-Bridge Multilevel Converter

Abstract: Despite its inherently modular hardware structure, the control system of most cascaded H-bridge converters is usually highly centralized and relies on a high-bandwidth intraconverter communication system to transmit time critical control signals to the module controllers. In contrast, this paper presents a decentralized control strategy for a modular cascaded converter, where each module controller determines its own switching actions based on local sensors, a local current regulator, and a local modulator. The system achieves the same performance as an optimized centralized control system while only requiring a low intraconverter communication bandwidth.

Crispr-cas systems and methods for altering expression of gene products, structural information and inducible modular cas enzymes

Abstract: The invention provides for systems, methods, and compositions for altering expression of target gene sequences and related gene products. Provided are structural information on the Cas protein of the CRISPR-Cas system, use of this information in generating modified components of the CRISPR complex, vectors and vector systems which encode one or more components or modified components of a CRISPR complex, as well as methods for the design and use of such vectors and components. Also provided are methods of directing CRISPR complex formation in eukaryotie cells and methods for utilizing the CRISPR-Cas system. In particular the present invention comprehends the engineering of optimized modular CRISPR-Cas enzyme systems.

Self-Start Control With Grouping Sequentially Precharge for the C-MMC-Based HVDC System

Abstract: The newly developed modular multilevel converter based on a clamp double submodule (CDSM), namely, C-MMC, has been identified as a good solution for high-voltage direct-current (HVDC) applications, due to its inherent unique dc fault blocking capability. This paper presents a self-start control strategy for the C-MMC-based HVDC link. The equivalent charging circuit for the uncontrolled precharging stage is derived and the behaviors of the CDSM are investigated. In addition, the selection of the current-limiting resistor is described. To fully charge the capacitors in submodules, a simple grouping sequentially controlled charge (GSCC) method is proposed. This method makes the capacitors be charged group by group so that each capacitor can share sufficient stored energy. In particular, detailed startup procedures are designed for the HVDC link under two conditions, that is, connecting to active grids and supplying the passive network. The feasibility of the GSCC scheme under cell failure conditions is discussed. The validity of the proposed strategies is verified by PSCAD/EMTDC simulations.

Metal−Organic Frameworks: Rise of the Ligands †

Abstract: Metal–organic frameworks (MOFs) are modular porous materials synthesized from metal cluster nodes and organic linkers that connect these nodes. This rapidly expanding class of structures presents viable platforms for applications in gas sorption and separation, catalysis, sensing, fuel processing, and environmental remediation and as porous conductive materials. These applications are increasingly relying on sophisticated ligands that have functional characteristics either as independent entities (that is, outside of MOFs) or that gain new functions once reticulated into the porous material. Thus, the traditionally inorganic area of MOF research begins to profit more and more from a comprehensive approach which combines insights from organic, inorganic, and materials chemistry. This Perspective highlights some of the second-generation MOFs prepared and studied using this holistic approach.

claspfolio 2: Advances in Algorithm Selection for Answer Set Programming

Abstract: Building on the award-winning, portfolio-based ASP solver claspfolio, we present claspfolio 2, a modular and open solver architecture that integrates several different portfolio-based algorithm selection approaches and techniques The claspfolio 2 solver framework supports various feature generators, solver selection approaches, solver portfolios, as well as solver-schedule-based pre-solving techniques The default configuration of claspfolio 2 relies on a light-weight version of the ASP solver clasp to generate static and dynamic instance features The flexible open design of claspfolio 2 is a distinguishing factor even beyond ASP As such, it provides a unique framework for comparing and combining existing portfolio-based algorithm selection approaches and techniques in a single, unified framework Taking advantage of this, we conducted an extensive experimental study to assess the impact of different feature sets, selection approaches and base solver portfolios In addition to gaining substantial insights into the utility of the various approaches and techniques, we identified a default configuration of claspfolio 2 that achieves substantial performance gains not only over clasp's default configuration and the earlier version of claspfolio, but also over manually tuned configurations of clasp

Timed Compatibility Analysis of Web Service Composition: A Modular Approach Based on Petri Nets

Abstract: Recently, the temporal constraint satisfiability is regarded as an important criterion in Web service composition to guarantee its timely completion. This leads to a new challenge in analyzing the compatibility of Web services under temporal constraints. The existing methods either do not consider message mismatches between services in a composition or suffer from state-space explosion by verifying a service composition model as a whole; or lack the ability to generate execution paths of each participating service. In this paper, we present a Petri net-based method to address these three issues in a holistic manner, and also in a modular way. Compared with the existing work, the proposed approach not only composes Web services by adding a mediation net to deal with message mismatches, but also checks the compatibility w.r.t. temporal constraints by generating modular timed state graphs. Furthermore, the reliable and usable execution paths that satisfy the timed compatibility can be derived to guide service execution and avoid any temporal exception.

A Prototype of Modular Multilevel Converters

Abstract: This paper introduces a modular multilevel converter (MMC) based prototype for investigating the control of large-scale MMCs. The prototype contains 264 submodules (SMs) totally, which are designed in such a way that they can be rearranged between the half-bridge model and full-bridge model conveniently. Therefore, the characteristics of various typologies based on voltage-sourced converters can be studied. Meanwhile, a novel control system for large-scale MMCs is proposed, which is characterized for modular design and excellent expansibility. The designed control system is composed of one central control unit and several arm control units, while each arm control unit is composed of several valve-group control units. Besides, a new voltage-balancing method composed of internal voltage balance and external voltage balance is proposed to balance the SM voltages. Finally, experiments on a three-phase dc/ac MMC are carried out to verify the prototype and the control system, as well as the new voltage-balancing method. The results show that the proposed control system is feasible and the new voltage-balancing method is valid.

Learning and Categorization in Modular Neural Networks

Abstract: Part 1 CALM - Categorizing And Learning Module: introduction description of CALM simulation studies of perfromance and self-organization in CALM. Part 2 Application: psychological models pattern recognition as a practical application genetic algorithms - modularity, learning and network design. Part 3 Evaluation of CALM.