Ease Of Reconfiguration Research Articles

A Review on Intelligent Reflecting Surfaces: Challenges and Opportunities Towards Secured Communications

ABSTRACTThis review examines the advanced development and implementation of intelligent reflecting surfaces (IRSs) in smart radio environments (SREs) to enhance secure communications. IRS technology, including intelligent walls and software‐controlled metasurfaces, is designed to manipulate electromagnetic waves, thereby significantly improving wireless communication. The study highlights the importance of dynamic, nearly passive IRS, which combine multiple elements to create surfaces capable of diverse wave manipulations. Cutting‐edge techniques such as nonorthogonal multiple access (NOMA) and machine learning are employed to optimize IRS functions, enhancing secrecy rates and resilience against eavesdropping. Despite their ease of reconfiguration and affordability, IRSs are vulnerable to several security threats, a concern that has not been extensively explored in current research. This review aims to fill this gap by offering a comprehensive analysis of the security challenges associated with IRS‐enabled wireless networks. The effectiveness of IRS is compared to traditional wireless relays, with special attention to the simultaneous transmitting and reflecting intelligent reflecting surface (STAR‐IRS) model that provides 360° coverage. Key findings suggest that IRS can greatly enhance secure communications, improving wireless network performance, reliability, and adaptability. This paper underscores the pivotal role of IRS technology in the future of wireless networks, presenting new opportunities for secure and efficient communication systems.

Monitoring model for enhancing adaptability in human–robot collaborative mold assembly

ABSTRACT Molds are assembled manually due to their inherent characteristics of low-volume and high-variety production. Given the ergonomic risks caused by heavy-handling and repetitive tasks and diverse requirements in mold assembly, collaborative robots offer adaptability and ease of reconfiguration, making them potential solutions to these challenges. This study introduces a monitoring model for human–robot collaborative mold assembly using two cobots. This model encompasses manual progress monitoring for cobot execution and position-sharing modules. Manual task actions are detected using the You-Only-Look-Once-v8 Nano model. Detected actions are subsequently classified into different states. These identified states are relayed to the cobots, enabling early execution and controlling the cobots’ entry into the assembly area. This study proposes a position-sharing approach to prevent collisions by receiving coordinates via Modbus between the two cobots. Most existing research has developed separate models for action and part recognition, excluding the utilization of recognition results to enable early execution. This study contributes to a novel model for monitoring manual progress to enable early execution of subsequent tasks and facilitate communication through position sharing during human–robot collaborative mold assembly tasks. The results show that assembly time and the risk of collisions between cobots can be reduced in human–robot collaborative mold assembly tasks.

A reconfigurable metamaterial using trapeziums and triangles with alternative connectivity

A category of metamaterial that can manifest a wide range of Poisson's ratio from positive to negative is presented herein. This metamaterial consists of rigid units in the shapes of right trapeziums and right triangles that are connected at their corners in the form of necks, which supply elastic restraint during relative rotation of the rigid units. The on-axes Poisson's ratio of the metamaterial was formulated by geometrical analysis. By assigning a rotational spring constant to the connecting necks, the total spring potential energy for a specific enclosure was obtained. This energy was then matched against the strain energy of deformation for the homogenized continuum of the metamaterial for the same enclosure to give the on-axes Young's moduli. Results reveal a configuration that enables the metamaterial to display sign-programmable Poisson's ratio. In addition to being able to adjust the on-axes Young's moduli relative to each other, two specific configurations have been identified that permit both on-axes Young's moduli to be equal. The ease of reconfiguration, the wide range of effective mechanical properties and the capability of the Poisson's ratio sign to be programmed, therefore, avail the metamaterial as a viable material for applications that require frequent in situ adjustment of effective properties.

Numerical and experimental investigation on the synthesis of extended Kalman filters for cable-driven parallel robots modeled through DAEs

Cable-driven parallel robots are parallel robots where light-weight cables replace rigid bodies to move an end-effector. Their peculiar design allows obtaining large workspaces, high-dynamic handlings, ease of reconfigurability and, in general, low-cost architecture. Knowing the full state variables of a cable robot may be essential to implement advanced control and monitoring strategies and imposes the development of state observers. In this work a general approach to develop nonlinear state observers based on an extended Kalman filter (EKF) is proposed and validated both numerically and experimentally by referring to a cable-suspended parallel robot. The state observer is based on a system model obtained by converting a set of differential algebraic equations into ordinary differential equations through different formulations: the penalty formulation, the Udwadia–Kalaba formulation, and the Udwadia–Kalaba–Phohomsiri formulation, which have been chosen since they can handle the presence of redundant constraints as often happens in cable-driven parallel robots. In the numerical investigation, the EKF is validated simulating encoders heavily affected by quantization errors to demonstrate the filtering capabilities of EKF. In the experimental investigation, a very challenging validation is proposed: only two sensors measuring the rotations of two motors are used to estimate the actual position and velocity of the end-effector. This result cannot be achieved by sole forward kinematics and clearly proves the effectiveness of the proposed observer.

Bi-Planar Trajectory Tracking with a Novel 3DOF Cable Driven Lower Limb Rehabilitation Exoskeleton (C-LREX).

Although Cable-driven rehabilitation devices (CDRDs) have several advantages over traditional link-driven devices, including their light weight, ease of reconfiguration, and remote actuation, the majority of existing lower-limb CDRDs are limited to rehabilitation in the sagittal plane. In this work, we proposed a novel three degrees of freedom (DOF) lower limb model which accommodates hip abduction/adduction motion in the frontal plane, as well as knee and hip flexion/extension in the sagittal plane. The proposed model was employed to investigate the feasibility of using bi-planar cable routing to track a bi-planar reference healthy trajectory. Various possible routings of four cable configurations were selected and studied with the 3DOF model. The optimal locations of the hip cuffs were determined using optimization. When compared with the five-cable routing configuration, the four-cable routing produced higher joint forces, which motivated the future study of other potential cable routing configurations and their ability to track bi-planar motion.

Kinematic and Dynamic Modeling and Workspace Analysis of a Suspended Cable-Driven Parallel Robot for Schönflies Motions

In recent years, cable-driven parallel robots (CDPRs) have drawn more and more attention due to the properties of large workspace, large payload capacity, and ease of reconfiguration. In this paper, we present a kinematic and dynamic modeling and workspace analysis for a novel suspended CDPR which generates Schönflies motions. Firstly, the architecture of the robot is introduced, and the inverse and forward kinematic problems of the robot are solved through a geometrical approach. Then, the dynamic equation of the robot is derived by separately considering the moving platform and the drive trains. Based on the dynamic equation, the dynamic feasible workspace of the robot is determined under different values of accelerations. Finally, experiments are performed on a prototype of the robot to demonstrate the correctness of the derived models and workspace.

Managing Device Lifecycle: Reconfigurable Constrained Codes for M/T/Q/P-LC Flash Memories

Flash memory devices are winning the competition for storage density against magnetic recording devices. This outcome results from advances in physics that allow storage of more than one bit per cell, coupled with advances in signal processing that reduce the effect of physical instabilities. Constrained codes are used in storage to avoid problematic patterns. Recently, we introduced binary symmetric lexicographically-ordered constrained codes (LOCO codes) for data storage and data transmission. This paper introduces simple constrained codes that support non-binary physical substrates; multi, triple, quad, and the currently-in-development penta-level cell (M/T/Q/P-LC) Flash memories. The new codes can be easily modified if problematic patterns change with time. These codes are designed to mitigate inter-cell interference, which is a critical source of error in Flash devices. The occurrence of errors is a consequence of parasitic capacitances in and across floating gate transistors, resulting in charge propagation from cells being programmed to the highest charge level to neighboring cells being programmed to lower levels. The new codes are called $q$-ary asymmetric LOCO codes (QA-LOCO codes), and the construction subsumes codes previously designed for single-level cell (SLC) Flash devices (A-LOCO codes). QA-LOCO codes work for a Flash device with any number, $q$, of levels per cell. For $q \geq 4$, we show that QA-LOCO codes can achieve rates greater than $0.95 \log_2 q$ information bits per coded symbol. The complexity of encoding and decoding is modest, and reconfiguring a code is as easy as reprogramming an adder. Capacity-achieving rates, affordable encoding-decoding complexity, and ease of reconfigurability support the growing development of M/T/Q/P-LC Flash memory devices, as well as lifecycle management as the characteristics of these devices change with time.

TIME INTERVAL SWITCHING DEVICE

The proposed electronic switching device, which is a replacement (analogue) of the electromechanical switch KEP-12. The status and time settings are set for each channel separately through the device menu. It is characterized by less time and ease of reconfiguration.

Microwave photonic filtering based on optical carrier suppression modulation

AbstractMicrowave photonic filters have the advantages of wide tunability, low loss, and ease of reconfiguration. In this article, we propose a simple and cost‐efficient technique for the implementation of microwave photonic filter through simulations. This technique for the implementation of microwave photonic filter is employing a multiwavelength source and dispersive fiber. The multiwavelengths have been generated by employing optical carrier suppression based modulation. It has been shown that the free spectral range (FSR) of the filter may be tuned from 4.26 to 3.55 GHz by simply varying the frequency of the RF sinusoidal signal being used for modulation from 25 to 30 GHz, respectively. Furthermore, the bandwidth of the filter may be tuned by varying the number of filter taps.

A virtual engineering based approach to verify structural complexity of component-based automation systems in early design phase

Highly diverse factors including technological advancements, uncertain global market and mass personalisation are believed to be main causes of ever-growing complexity of manufacturing systems. Although complex systems may be needed to achieve global manufacturing requirements, complexity affects on various factors, such as: system development effort and cost, ease of re-configuration, level of skill required across the system life-cycle (e.g. design, operate and maintain). This article aims to develop a scientifically valid and industrially applicable complexity assessment approach to support early life-cycle phases of component-based automation systems against unwanted implications of structural system complexity. The presented approach defines component-based automation system as a constellation of basic components which can be represented in various design domains, such as: mechanical, electrical, pneumatic, control, etc. Accordingly, structural complexity is expressed as the combination of both inherent complexity of system entities and topological complexity resulting from the integration of elements of such constellations in a multi-layered network. The proposed approach is used to specify and implement a complexity assessment module which can be integrated into a series of virtual system design software solutions, in order to add complexity assessment as part of the design support and validation tools used by manufacturing engineers. Consequently, the proposed approach is integrated into the vueOne virtual engineering tool, wherein virtual automation system design data can be streamlined and used as input to the theoretical complexity model. In the developed tool, only mechanical and logical design domains are considered due to the limited data availability in early design phase. Inherent complexity of both mechanical and logical system entities and their interactions are expressed as a function of domain-specific design elements, and topological complexity is defined as the graph energy of the corresponding design connectivity matrix. Furthermore, the values of mathematical model parameters are determined based on an optimisation study, where subjective opinions of system/control engineers regarding the effort/difficulty associated with the development of thirty different component-based automation system designs are correlated with the corresponding complexity model outputs to minimise the prediction errors. The proposed approach is also demonstrated on a modular production system consisting of four sub-modules. The study shows that the approach can help designers/managers to better identify root causes of structural system complexity, and provides a systemic approach to compare alternate system designs during early system planning phase.

Passive RFID-Based Inventory of Traffic Signs on Roads and Urban Environments.

This paper presents a system with location functionalities for the inventory of traffic signs based on passive RFID technology. The proposed system simplifies the current video-based techniques, whose requirements regarding visibility are difficult to meet in some scenarios, such as dense urban areas. In addition, the system can be easily extended to consider any other street facilities, such as dumpsters or traffic lights. Furthermore, the system can perform the inventory process at night and at a vehicle’s usual speed, thus avoiding interfering with the normal traffic flow of the road. Moreover, the proposed system exploits the benefits of the passive RFID technologies over active RFID, which are typically employed on inventory and vehicular routing applications. Since the performance of passive RFID is not obvious for the required distance ranges on these in-motion scenarios, this paper, as its main contribution, addresses the problem in two different ways, on the one hand theoretically, presenting a radio wave propagation model at theoretical and simulation level for these scenarios; and on the other hand experimentally, comparing passive and active RFID alternatives regarding costs, power consumption, distance ranges, collision problems, and ease of reconfiguration. Finally, the performance of the proposed on-board system is experimentally validated, testing its capabilities for inventory purposes.

Optimized and Portable FPGA-Based Systolic Cell Architecture for Smith-Waterman-Based DNA Sequence Alignment

The alignment of DNA sequences is one of the important processes in the field of bioinformatics. The Smith–Waterman algorithm (SWA) performs optimally for aligning sequences but is computationally expensive. Field programmable gate array (FPGA) performs the best on parameters such as cost, speed-up, and ease of re-configurability to implement SWA. The performance of FPGA-based SWA is dependent on efficient cell-basic implementation-unit design. In this paper, we present an optimized systolic cell design while avoiding oversimplification, very large-scale integration (VLSI)-level design, and direct mapping of iterative equations such as previous cell designs. The proposed design makes efficient use of hardware resources and provides portability as the proposed design is not based on gate-level details. Our cell design implementing a linear gap penalty resulted in a performance improvement of 32× over a GPP platform and surpassed the hardware utilization of another implementation by a factor of 4.23.

Design and implementation of a dynamic FPAA based photovoltaic emulator

In this paper, a new Photovoltaic (PV) emulator is presented and discussed. Its main feature is represented by the use of a Field Programmable Analog Array (FPAA) on which the desired current vs. voltage (I–V) PV characteristic can be implemented. The FPAA provides a suitable analog time varying reference signal for the output current control of a proper DC/DC converter whose output port emulates the PV I–V curve. The proposed emulator allows to track time varying irradiance values and therefore it allows also to emulate typical scenarios of automotive applications or involving fast time varying weather conditions (e.g. the ones which usually occur in tropical locations). Additional, not less important advantages of the proposed solution are the following ones: (1) no numerical interpolations and no storage of big amount of data in memory are required; (2) the FPAA is characterized by a great ease of reconfiguration and programming with respect to FPGA or DSP based implementations; (3) no DAC or ADC converters are needed; (4) not only uniform but also mismatching operating conditions can be easily emulated; (5) power sources different from PV sources can be easily emulated by using the same architecture. The presented experimental results allow to confirm the validity of the proposed FPAA based architecture.

FSL-based Hardware Implementation for Parallel Computation of cDNA Microarray Image Segmentation

The present paper proposes a FPGA based hardware implementations for microarray image processing algorithms in order eliminate the shortcomings of the existing software platforms: user intervention, increased computation time and cost. The proposed image processing algorithms exclude user intervention from processing. An application-specific architecture is designed aiming microarray image processing algorithms parallelization in order to speed up computation. Hardware architectures for logarithm based image enhancement, profile computation and image segmentation are described. The methodology to integrate the hardware architecture within a microprocessor system is detailed. The Fast Simplex Link (FSL) bus is used to connect the hardware architecture as speed up co-processor of the microarray image processing system. Timing considerations were presented considering the levels of parallelism that can be achieved by using our proposed hardware architectures. The FPGA technology was chosen for implementation, due to its parallel computation capabilities and ease of reconfiguration.

Service Level as Performance Index for Reconfigurable Manufacturing System Involving Multiple Part Families

In this global manufacturing era, one of the important challenges faced by manufacturer is how to deal with stochastic demand and ever changing customer needs and requirements. Reconfigurable manufacturing systems are recognized as next generation manufacturing systems capable of providing the exact functionality and capacity as and when required. Some important performance indices studied in the past include cost, ease of reconfigurability, productivity, reliability and availability for assessing the performance of these systems. The economics while carrying out the reconfiguration process of these systems must include parameters such as cost incurred while producing orders of part families on a particular configuration and the reconfiguration cost associated while changing over from initial configuration to another. The complexity and cost involved from changing one configuration to another depends on the existing initial configuration and the new configuration required for subsequent production. In this paper, based on the different efforts associated with the reconfiguration process, a new index of performance termed as “Service Level” is proposed. The proposed indicator is modeled for a multiple part family reconfigurable manufacturing system. The methodology proposed is explained using a numerical example. The results obtained along with their important implications were discussed.

Comparing the Control Structures of ISA S88- and Holonic Component-Based Architecture

It is generally believed that a distributed intelligent system, such as a holonic manufacturing system (HMS), should be more reconfigurable than a conventional hierarchical manufacturing system (HiMS). However, a recent case study suggested that the control structure of a modern HiMS, such as ISA S88-based manufacturing system, can-under certain condition-be as reconfigurable as that of a HMS, such as holonic component-based architecture (HCBA)-based manufacturing system . This result is particularly interesting and this paper focuses on clarifying this issue. This is done by analyzing the control structure and the ease of reconfiguration of both HCBA and ISA S88-based manufacturing systems. It is found that both architectures possess similar level of ease of reconfiguration because both architectures are product-driven manufacturing control and their control functions are independent to product and production system.

Assessing ease of reconfiguration of conventional and Holonic manufacturing systems: Approach and case study

This paper focuses on comparing the ease of reconfiguration of Holonic and conventional manufacturing systems (HMS and CMS). By using the recently proposed guideline for assessing ease of reconfiguration [Covanich, W., McFarlane, D., Farid, A.M., 2008. Guidelines for Evaluating the Ease of Reconfiguration of Manufacturing Systems. Daejeon, South Korea. INDIN08], the paper evaluates the effort required to introduce a new machine into both conventional and Holonic manufacturing systems. Examining particularly the ease of reconfiguration, it is found that HMS with conventional hardware may have little advantage over CMS, while HMS with ideal hardware appears to have significant advantage over CMS.

Production degrees of freedom as manufacturing system reconfiguration potential measures

In recent years, many design approaches have been developed for automated manufacturing systems in the fields of reconfigurable manufacturing systems (RMSs), holonic manufacturing systems (HMSs), and multi-agent systems (MASs). One of the principle reasons for these developments has been to enhance the reconfigurability of a manufacturing system, allowing it to adapt readily to changes over time. However, to date, reconfigurability assessment has been limited. Hence, the efficacy of these design approaches remains inconclusive. This paper is the first of two in this issue to address reconfigurability measurement. Specifically, it seeks to address ‘reconfiguration potential’ by analogy. Mechanical degrees of freedom have been used in the field of mechanics as a means of determining the independent directions of motion of a mechanical system. By analogy, manufacturing degrees of freedom can be used to determine independent ways of production. Furthermore, manufacturing degrees of freedom can be classified into their production and product varieties. This paper specifically focuses on the former to measure the product-independent aspects of manufacturing system ‘reconfiguration potential’. This approach will be added to complementary work on the measurement of ‘reconfiguration ease’ so as to form an integrated reconfigurability measurement process described elsewhere [1—5].

Facilitating ease of system reconfiguration through measures of manufacturing modularity

In recent years, many design approaches have been developed for automated manufacturing systems in the fields of reconfigurable manufacturing systems (RMSs), holonic manufacturing systems (HMSs), and multiagent systems (MASs). One of the principle reasons for these developments has been to enhance the reconfigurability of a manufacturing system, allowing it to adapt readily to changes over time. However, to date reconfigurability assessment has been limited. Hence the efficacy of these design approaches remains inconclusive. This paper is the second of two in this issue to address reconfigurability measurement. Specifically, ‘reconfiguration ease’ has often been qualitatively argued to depend on the system's modularity. For this purpose, this paper develops modularity measures in a three-step approach. Firstly, the nature of typical manufacturing system interfaces is discussed. Next, the qualitative understanding underlying existing modularity measures is distilled. Finally, these understandings are synthesized for a manufacturing system context. This approach forms the second of two pillars that together lay the foundation for an integrated reconfigurability measurement process described elsewhere.

Building Robust Wireless LAN for Industrial Control with the DSSS-CDMA Cell Phone Network Paradigm

Wireless LAN for industrial control (IC-WLAN) provides many benefits, such as mobility, low deployment cost, and ease of reconfiguration. However, the top concern is robustness of wireless communications. Wireless control loops must be maintained under persistent adverse channel conditions, such as noise, large-scale path loss, fading, and many electromagnetic interference sources in industrial environments. The conventional IEEE 802.11 WLANs, originally designed for high bandwidth instead of high robustness, are therefore inappropriate for IC-WLAN. A solution lies in the direct sequence spread spectrum (DSSS) technology: by deploying the largest possible processing gain (slowest bit rate) that fully exploits the low data rate feature of industrial control, much higher robustness can be achieved. We hereby propose using DSSS-CDMA to build IC-WLAN. We carry out fine-grained physical layer simulations and Monte Carlo comparisons. The results show that DSSS-CDMA IC-WLAN provides much higher robustness than IEEE 802.11/802.15.4 WLAN, so that reliable wireless industrial control loops become feasible. We also show that deploying larger processing gain is preferable, to deploying more intensive convolutional coding. The DSSS-CDMA IC-WLAN scheme also opens up a new problem space for interdisciplinary study, involving real-time scheduling, resource management, communication, networking, and control