Reconfigurable Modules Research Articles

The modular organization of brain cortical connectivity across the human lifespan

The network architecture of the human brain contributes in shaping neural activity, influencing cognitive and behavioral processes. The availability of neuroimaging data across the lifespan allows us to monitor how this architecture reorganizes, influenced by processes like learning, adaptation, maturation, and senescence. Changing patterns in brain connectivity can be analyzed with the tools of network science, which can be used to reveal organizational principles such as modular network topology. The identification of network modules is fundamental, as they parse the brain into coherent sub-systems and allow for both functional integration and segregation among different brain areas. In this work we examined the brain’s modular organization by developing an ensemble-based multilayer network approach, allowing us to link changes of structural connectivity patterns to development and aging. We show that modular structure exhibits both linear and nonlinear age-related trends. In the early and late lifespan, communities are more modular, and we track the origins of this high modularity to two different substrates in brain connectivity, linked to the number and the weights of the intra-clusters edges. We also demonstrate that aging leads to a progressive and increasing reconfiguration of modules and a redistribution across hemispheres. Finally, we identify those brain regions that most contribute to network reconfiguration and those that remain more stable across the lifespan.

Optimal Runtime Algorithm to Improve Fault Tolerance of Bus-Based Reconfigurable Designs

This article presents an approach to providing fault tolerance to permanent effects in the substrate of dynamic, partially reconfigurable field-programmable gate arrays (FPGAs). Our proposal consists of modifying FPGA configuration at runtime to avoid permanently damaged regions of the FPGA. It demands that the circuit design fulfills several requirements regarding the functionality and interfaces of its reconfigurable modules, the structure of the communications, the inclusion of specialized modules to handle and optimize circuit reconfiguration at runtime, and the organization of the reconfigurable partitions. We evaluate two methods to select the new target partition for modules in faulty partitions and design their hardware as intellectual property modules. We evaluate the performance and scalability of this approach using a trapezoidal shaper, a filter used to detect high-energy particles in radiation experiments, and we carry out the experiments with a variable number of modules and reconfigurable partitions using the two selection algorithms. The proposal is compared with nonfault-tolerant and triple modular redundancy approaches, and it remains functional with up to $12\times $ more injected faults than those.

Modular multi-motor exercise system for space exploration

The goal of this project is to develop new technology that will support crew health and performance during long duration space missions. While there are current methods for maintaining fitness aboard the International Space Station, the results are not ideal; muscle mass and bone density continue to degrade, and there is still room for improvement. Moreover, new exploration missions need to maximize the use of the equipment due to storage limitations. A system that can be used for multiple purposes such as for providing multiple strength training exercises, as well as, providing aerobic exercises while using the same workout space is desirable. This project aims to address these challenges by introducing a modular system that will bring versatility, scalability, and robustness, by using mountable and reconfigurable modules to maximize the number of exercises that can be performed. In this paper we present the development of a Modular Multi-Motor Exercise System concept based on Magneto-Rheological fluid-based modules.

Innovation in online higher-education services: building complex systems

ABSTRACT Digitization is increasing the complexity and variety of educational services supplied and demanded. However, there is a lack of a systematic treatment of this phenomenon from the perspective of innovation and entrepreneurship. This paper employs the complex adaptive systems approach to explore how digitization changes the characteristics, generativity (combinatorial possibilities) and architecture of online educational services. Our main claims are that: (a) online courses (OCs) are modular complex hierarchical systems; (b) the development of new OCs is a significant type of innovation (not limited merely to technological change) brought about by entrepreneurial reconfiguration of modules that create new combinations in the design space of new educational services; (c) these new combinations generate new OC systems; and (d) OCs are embedded in broader institutional and social structures (e.g. universities) that co-evolve with technological change. By means of a formal combinatorial model, we examine the computational mechanism and the principles of connection-making that govern how new OCs are created and adapted.

Computation of Power Extraction From Photovoltaic Arrays Under Various Fault Conditions

Photovoltaic (PV) faults such as partial shading, bypass-diode defects, degradation of PV modules, and wiring issues greatly affect the power output and cause various peaks in P-V curves of a PV system. Although, commonly used Total-Cross-Tied (TCT) scheme in PV arrays is considered instrumental for reducing power losses there lies a great scope to evaluate power extraction through reconfiguration of modules with different PV materials. This paper presents detailed investigation of power extraction using number placement reconfiguration method under numerous faults. PV power extraction is carried out and compared with three different interconnections of PV modules, including series-parallel (SP), bridge-link (BL) and TCT. In order to conduct a thorough investigation and better evaluate the performance of PV arrays, we have studied reconfiguration of PV modules with polycrystalline and copper indium gallium selenide (CIGS) PV technologies. In addition, this paper contains detailed quantification of the impact of the studied PV faults on power grid. The results obtained in MATLAB/Simulink demonstrate that CIGS PV technology performs better than polycrystalline in terms of power output during different faulty conditions. It becomes evident from the presented results that optimal reconfiguration of PV arrays can increase the power extraction from PV system with reduced number of P-V peaks. Hence, leading to improved performance of the PV system.

Hierarchical Control of a Quadcopter under Stuck Actuator Fault

Abstract We propose a hierarchical FTC (Fault Tolerant Control) scheme for trajectory tracking by a quadcopter system under stuck actuator fault and actuator saturation. Both the FDI (Fault Detection and Isolation) and control reconfiguration modules are implemented at the low-level associated with the rotation dynamics through a NMPC (Nonlinear Model Predictive Control) strategy. The uncontrolled (when under fault) yaw torque is predicted and compensated by the NMPC. It is shown that the overall control scheme succeeds in maintaining trajectory tracking for various fault events (both in the sense of having various stuck values and in the sense of changing the actuator under fault).

Cost Effective Offline Reconfiguration for Large-Scale Non-Uniformly Aging Photovoltaic Arrays Efficiency Enhancement

In the past decades, a huge number of large-scale photovoltaic (PV) plants have been constructed all around the world. However, the capital and operational costs can be high, which limits their widespread applications. Because the installed PV modules often operate in harsh environments (i.e. storm, high temperature, dust, hail, etc.), non-uniform aging phenomena of PV modules cannot be avoided and it impacts adversely on the performance of PV plants, especially in the middle and late periods of their service life. This paper develops an offline PV module reconfiguration strategy for the non-uniform aging PV array to mitigate this effect. In order to maximize the economic benefit, electricity price and labor cost are considered in the offline reconfiguration. The Branch-and-Bound based optimization algorithm is proposed to find the highest economic benefit. In order to verify the proposed algorithm, MATLAB software-based modelling and simulation have been performed in four case studies, in which a typical 42kW PV array with 7 × 20 connection is employed in a testing benchmark, and the manpower cost and electricity price in USA, UK, China and Turkey are considered in the case study. The results demonstrate that the economic benefit from a non-uniformly aged PV array is further enhanced with the proposed reconfiguration method.

Embryonics Based Phased Array Antenna Structure With Self-Repair Ability

The reliability of phased array antenna can be improved with the self-repairing technology, and the existing self-repair method based on the TR module reconfiguration has problems such as slow calculation speed and difficulty in calculating the elements' mutual coupling, which is difficult to meet the application requirements. In this paper, a novel phased array antenna structure with self-repair ability is proposed. Based on the embryological electronics (embryonics), a novel phased array antenna structure with TR cell as the basic unit is constructed. The faulty TR cell can be detected and removed, and its influence on the phased array antenna's performance can be eliminated. The function and connection of faulty TR cell can be implemented by the normal TR cells and idle TR cells, the performance of phased array antenna can be repaired in real-time. TR cell, TR cell array and input/output switching control module are designed. The simulation tests show that, the phased array antenna with various fault conditions can be repaired in real-time based on the proposed structure, and the performance of phased array antenna can be repaired to the initial normal state with enough idle TR cells in array. Even without the idle TR cell, the performance of phased array antenna with fault can be improved through the self-repair. A new way for the design of phased array antenna design with self-repair ability is provided.

Near-Fastest Battery Balancing by Cell/Module Reconfiguration

Charge imbalance is a very common issue in multi-cell /module/pack battery systems due to manufacturing variations, inconsistent charging/discharging, and uneven thermal distribution. As a consequence, the deliverable charge capacity, battery lifespan, and system reliability may all decrease over time. To tackle this issue, various external circuit designs can be attached for charge balance, and the internal battery cell/module/pack connection can also significantly affect the charge balance performance. This paper focuses on minimizing the battery charge equalization (BCE) time by battery cell/module reconfiguration. Specifically, for the reconfigurable module-based BCE system, we propose reconfiguration algorithms for fast charge equalization under different levels of system reconfigurability. For battery systems allowing module reconfiguration and intra-module cell reconfiguration, the proposed module-based bounded reconfiguration algorithm can reach or get very close to the minimum BCE times obtained by exhaustive search. When the reconfigurability level is extended by allowing inter-module cell reconfiguration, the proposed module-based complete reconfiguration algorithm can achieve similar optimality to that of the genetic algorithm (GA). Moreover, as compared to the circuit experiments, exhaustive search, and GA, the proposed algorithms take much less computational time. The optimality and computational efficiency of the proposed algorithms are demonstrated by both circuit and numerical experiments.

Switch for the Optimization of Module Power by Reconfiguration of All Strings (SOMBRA): An Insulated Integrated Switch for a Reconfigurable Solar Panel

The energy yield of a solar panel can be severely impacted by partial shading. Shade caused by nearby static objects can hardly be avoided in installations such as building-applied or building-integrated photovoltaics. Smart reconfigurable photovoltaics (PV) panels are able to change their intra-module configuration to reduce this impact: small substrings can be rewired to be connected in a more optimal configuration. To achieve this, a reconfiguration switch needs to be designed. In this paper a switch for the optimization of module power by reconfiguration of all strings (SOMBRA), a smart switch, is presented. SOMBRA is a fully integrated, low-ohmic switch, designed for currents up to 10 A. It is fully floating up to 50 V, while still being able to communicate with a central unit as an inter-integrated circuit (I 2 C) slave. Two versions were realized, SOMBRA-LV10 for low voltages (LV) and a load current of 10 A, and SOMBRA-HV05 for high voltages (HV) and a load current of 5 A. Measurements proved these devices to be functional, measuring an on-resistance of 1.3 m Ω for SOMBRA-LV10 and 7.3 m Ω for SOMBRA-HV05. This paper will elaborate on the operation, design, and implementation of SOMRBA, as well as the first tests with a small reconfigurable PV module.

Power rating analysis and protection for photovoltaic-isolated port based differential power processing systems

In a photovoltaic generation system (PGS), photovoltaic (PV) modules are often connected in series for increased string voltage. However, a significant reduction in the actual output power is observed due to the manufacturing tolerance, module aging and partial shaded. Compared with conventional methods such as bypass diodes and PV module reconfiguration, modular distributed architecture especially the differential power processing (DPP) is able to yield high output power even under partial shading conditions. Moreover, the system efficiency is improved since only the differential power is processed by the DPP converters. This paper mainly focuses on the power rating analysis and protection of PV-isolated Port (PV-IP) based DPP systems considering the significant power stress difference among DPP converters under different partial shading conditions. The voltage equalization (VE) control used in this work is able to provide up to 77% efficiency improvement through the simulation evaluation. The protection algorithm is proposed for the PV-IP DPP architecture to improve the system reliability even when some DPP converters are found failed. With the proposed protection strategy, not only the high output power yield can be maintained, but also the modular design of DPP converters with smaller power capacity can be achieved. Simulation and indoor experimental tests under various partial shading conditions were carried out to validate the effectiveness of the proposed power rating analysis and protection scheme.

Design and evaluation of dynamic partial reconfiguration using fault tolerance in asynchronous FPGA

In the recent past, the FPGA mechanism is a leading achievement medium for electronic digital circuit design. The digital systems are operated with both asynchronous and synchronous mode with multiple clocks. This paper presents fault tolerance to a grid of asynchronous clocked run time reconfigurable modules with dynamic and partially reconfigurable on FPGA. The fault tolerance of dynamic partial reconfiguration (DPR) model based on fault tolerance system in asynchronous clock operation model is implemented for FPGA. The proposed algorithm for DPR in the presence of faults uses the equalizer technique to eliminate the faults during the processing. The DPR reduces the runtime and memory space is saved by the partial reconfiguration in parallel computing of FPGA. The overall throughput of the development system is high for multiple clock domains within the grid. The performance of the proposed system is compared with the synchronous clocked grid system to prove the efficiency of the DPR. Experimental results show that the high efficiency and accuracy of the DPR with fault tolerance of FPGAs.

Forgetting in Modular Answer Set Programming

Modular programming facilitates the creation and reuse of large software, and has recently gathered considerable interest in the context of Answer Set Programming (ASP). In this setting, forgetting, or the elimination of middle variables no longer deemed relevant, is of importance as it allows one to, e.g., simplify a program, make it more declarative, or even hide some of its parts without affecting the consequences for those parts that are relevant. While forgetting in the context of ASP has been extensively studied, its known limitations make it unsuitable to be used in Modular ASP. In this paper, we present a novel class of forgetting operators and show that such operators can always be successfully applied in Modular ASP to forget all kinds of atoms – input, output and hidden – overcoming the impossibility results that exist for general ASP. Additionally, we investigate conditions under which this class of operators preserves the module theorem in Modular ASP, thus ensuring that answer sets of modules can still be composed, and how the module theorem can always be preserved if we further allow the reconfiguration of modules.

Transcranial Magnetic Stimulation to the Middle Frontal Gyrus During Attention Modes Induced Dynamic Module Reconfiguration in Brain Networks.

The interaction between dorsal and ventral attention networks (VANs) is mediated by the middle frontal gyrus (MFG), which is functionally connected to both networks. However, the direct role of the MFG in selective and sustained attention remains controversial. In the current study, we used transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to probe the connectivity dynamic changes of MFG-associated regions during different attention modes. The participants underwent visual, selective, and sustained attention tasks to observe TMS-induced network changes. Twenty healthy participants received single-pulse TMS over the left or right MFG during tasks, while synchronous EEG data was acquired. Behavioral results were recorded and time-varying brain network analyses were performed. We found that the MFG is involved in attention processing and that sustained attention was preferentially controlled by the right MFG. Moreover, compared with the right hemisphere, the left hemisphere was associated with selective attention tasks. Visual and selective attention tasks induced MFG-related changes in network nodes were within the left hemisphere; however, sustained attention induced changes in network nodes were in the bilateral posterior MFG. Our findings indicated that the MFG plays a crucial role in regulating attention networks. In particular, TMS-induced MFG alterations influenced key nodes of the time-varying brain network, leading to the reorganization of brain network modules.

Dynamically Reconfigurable Encryption and Decryption System Design for the Internet of Things Information Security.

Information security is the foundation for building trust between the Internet of Things (IoT) and its users. Due to the sharp increase of information quantity and the limitation of hardware resources, it is difficult to maintain the high performance of hardware equipment, while also enhancing information security. To solve the problem of high consumption and low flexibility of multiple cryptographic algorithms hardware implementation, we have designed the Dynamically Reconfigurable Encryption and Decryption System, which is based on Field Programmable Gate Array. Considering the functional requirements, the cryptographic algorithm reconfigurable module files stored in External Memory could be configured dynamically into the assigned on-chip Reconfigurable Partition, supported by Core Controller and the Reconfiguration Control Platform. The experiment results show that, compared with the Static Encryption and Decryption System, our design reduces the logic resources by more than 30% and completes the algorithm swapping at the configuration speed of 15,759.51 Bytes/ms. It indicates that our design could reduce logic resources consumption and improve utilization efficiency and system flexibility.

Graph Theory-Based Approach to Accomplish Complete Coverage Path Planning Tasks for Reconfigurable Robots

Extensive studies regarding complete coverage problems have been conducted, but a few tackle scenarios where the mobile robot is equipped with reconfigurable modules. The reconfigurability of these robots creates opportunities to develop new navigation strategies with higher dexterity; however, it also simultaneously adds in constraints to the direction of movements. This paper aims to develop a valid navigation strategy that allows tetromino-based self-reconfigurable robots to perform complete coverage tasks. To this end, a novel graph theory-based model to simulate the workspace coverage and make use of dynamic programming technique for optimal path searching and adaptive robot morphology shifting algorithms is proposed. Moreover, the influence of algorithms starting variables on workspace coverage outcome is analyzed thoughtfully in this paper. The simulation results showed that the proposed method is capable of generating navigation paths throughout the workspace, which ensures complete workspace coverage while minimizing the total number of actions performed by the robot.

Evaluation of confound regression strategies for the mitigation of micromovement artifact in studies of dynamic resting-state functional connectivity and multilayer network modularity.

Dynamic functional connectivity reflects the spatiotemporal organization of spontaneous brain activity in health and disease. Dynamic functional connectivity may be susceptible to artifacts induced by participant motion. This report provides a systematic evaluation of 12 commonly used participant-level confound regression strategies designed to mitigate the effects of micromovements in a sample of 393 youths (ages 8–22 years). Each strategy was evaluated according to a number of benchmarks, including (a) the residual association between participant motion and edge dispersion, (b) distance-dependent effects of motion on edge dispersion, (c) the degree to which functional subnetworks could be identified by multilayer modularity maximization, and (d) measures of module reconfiguration, including node flexibility and node promiscuity. Results indicate variability in the effectiveness of the evaluated pipelines across benchmarks. Methods that included global signal regression were the most consistently effective de-noising strategies.

A cost-benefit analysis for reconfigurable PV modules under shading

Non-uniform conditions within a PV module lead to significant energy losses in conventional topologies. Some of the energy lost due to partial shading can be recovered by installing reconfigurable modules. In order to explore the potential benefits of reconfigurable topologies in installations where non-uniform conditions are dominant, three shading scenarios are simulated throughout the year, both for reconfigurable and conventional modules. This allows the evaluation of the performance of each topology and estimation of the long-term gains. Using a cost function, which includes the additional investment cost, the energy gain can be translated to financial terms. Through this, locations where reconfigurable topologies can be beneficial, both in energy and financial terms, can be identified. The methodology is applied to the case of reconfigurable PV modules with a snake-like configuration. Simulation results show that these PV modules allow for higher energy production compared to conventional modules under all the simulated shading scenarios. However, they remain economically profitable over 20 years only in locations where partial shading is expected to occur daily, either throughout the full year or at least in the period of the year where energy generation is high.

Test of Reconfigurable Modules in Scan Networks

Modern devices often include several embedded instruments, such as BIST interfaces, sensors, calibration facilities. New standards, such as IEEE Std 1687, provide vehicles to access these instruments. In approaches based on reconfigurable scan networks (RSNs), instruments are coupled with scan registers, connected into chains and interleaved with reconfigurable modules. Such modules embed reconfigurable multiplexers that permit a selective access to different parts of the chain. A similar scenario is also supported by IEEE Std 1149.1-2013. The test of permanent faults affecting an RSN requires to shift test vectors throughout a certain number of network configurations. This paper presents some methodologies to select the list of configurations that perform the complete test of the reconfigurable modules of the RSN. In particular, one method is presented that, by construction, can be proved to be able to apply the test in the minimum amount of clock cycles. Other methods are sub-optimal in terms of test application time (TAT), but scale well on large circuits. In order to provide a comparison between the proposed methods, experimental results on some benchmark RSNs are provided.

Evaluation and optimization of the design schemes of reconfigurable machine tools based on multiple-attribute decision-making

A reconfigurable manufacturing system is one designed for rapid change in its structure, to quickly adjust its production capacity and functionality within a part family. Aiming at the diversity, cost and complexity of reconfiguration design, a method for evaluating the design scheme of a reconfigurable machine tool based on VIKOR is proposed. The module similarity between a reconfigurable machine tool and a prototype machine tool is defined, and on this basis, three quantitative evaluation indicators are established as follows: the module chain similarity determines the difficulty, effort, time and efficiency of machine tool reconstruction; the module interface complexity determines the feasibility and complexity of the disassembly and assembly of the reconfiguration module; and the reconfiguration cost determines the economic advantages of reconfigurable machines relative to fixed-structure equipment. According to three indicators, a multi-attribute decision-making method based on VIKOR is used to evaluate, calculate and sort the design scheme set of the reconfigurable machine tool, and the optimal feasible solution is obtained. An example of the reconfiguration design of a machine tool is analysed to verify the validity and feasibility of the proposed method compared with the methods of simple average weighting and technique for order preference by similarity to an ideal solution.