Parallel Link Research Articles

Energy harvester for safety shoes using parallel piezoelectric links

Energy-harvesting devices in shoes have attracted much attention from the fields of elderly support, sports science, and disaster mitigation. In this study, we developed an energy harvester with a parallel link structure and six multi-layered piezoelectric transducers. By using this structure, we realized an effective energy conversion compared with conventional energy harvesters in terms of maximum power, comfort, durability, and availability of inputs with six degrees of freedom. A prototype of the parallel-link piezoelectric energy harvester generated 1.29 mW with human body weight. As a trial use, this energy harvester was installed in safety shoes for powering LEDs in the shoes. The assembly produced a brightness of 0.5 cd on average over a duration of 0.5 s, which is enough to show the wearer his or her position in a dark place.

Boundaries of Operation for Refurbished Parallel AC–DC Reconfigurable Links in Distribution Grids

Parallel ac-dc reconfigurable link technology can find interesting applications in medium voltage power distribution. A given system can operate in different configurations while maintaining equivalent capacity during (n-1) contingencies. It is proved that within the defined operating boundaries, a parallel ac-dc configuration has higher efficiency as compared to pure ac or pure dc power delivery. Using sensitivity analysis, the variations in these efficiency boundaries with power demand, power factor, grid voltages, link lengths, conductor areas and converter efficiency is described. It is shown that parallel ac-dc system can have smaller payback time as compared to a purely dc power transmission for the same capacity due to lower investment cost in converter station and superior efficiency. As compared to a purely ac system, the payback of a refurbished parallel acdc configuration can be less than 5 years for a 10 km, 10 kV distribution link within the specified assumptions and operating conditions.

Optimizing the Performance of Breast Cancer Classification by Employing the Same Domain Transfer Learning from Hybrid Deep Convolutional Neural Network Model

Breast cancer is a significant factor in female mortality. An early cancer diagnosis leads to a reduction in the breast cancer death rate. With the help of a computer-aided diagnosis system, the efficiency increased, and the cost was reduced for the cancer diagnosis. Traditional breast cancer classification techniques are based on handcrafted features techniques, and their performance relies upon the chosen features. They also are very sensitive to different sizes and complex shapes. However, histopathological breast cancer images are very complex in shape. Currently, deep learning models have become an alternative solution for diagnosis, and have overcome the drawbacks of classical classification techniques. Although deep learning has performed well in various tasks of computer vision and pattern recognition, it still has some challenges. One of the main challenges is the lack of training data. To address this challenge and optimize the performance, we have utilized a transfer learning technique which is where the deep learning models train on a task, and then fine-tune the models for another task. We have employed transfer learning in two ways: Training our proposed model first on the same domain dataset, then on the target dataset, and training our model on a different domain dataset, then on the target dataset. We have empirically proven that the same domain transfer learning optimized the performance. Our hybrid model of parallel convolutional layers and residual links is utilized to classify hematoxylin–eosin-stained breast biopsy images into four classes: invasive carcinoma, in-situ carcinoma, benign tumor and normal tissue. To reduce the effect of overfitting, we have augmented the images with different image processing techniques. The proposed model achieved state-of-the-art performance, and it outperformed the latest methods by achieving a patch-wise classification accuracy of 90.5%, and an image-wise classification accuracy of 97.4% on the validation set. Moreover, we have achieved an image-wise classification accuracy of 96.1% on the test set of the microscopy ICIAR-2018 dataset.

Optimal Power Flow Control in Parallel Operating AC and DC Distribution Links

DC links with back to back voltage source converters are usually built alongside the existing medium voltage ac distribution grids for infrastructure reinforcement. The distribution network operators need to run multiple of such parallel ac and dc links between two substations at optimal efficiency. This article shows that the active power steering capability of the dc link can be used to dynamically vary the share of power flow in the ac link such that the system operating efficiency is maximized for varying power demand, grid voltage, dc-link voltage, converter efficiency, link length, and conductor area. The algorithm developed based on the derived exact and estimated solution for this parallel ac-dc link power sharing ratio is proved through simulations on a 10 kV, 30 MVA system. The concept is validated using experiments on a scale-down lab model. Using case-study with adapted measured substation data of hourly average power demand profile for one year, it is shown that annual energy saving potential in the range of 8-92 MWh can be achieved with varying link length between 10-20 km for 5-20 kV grid voltage and 185-630 mm$^2$ conductor area if the proposed optimal power flow control is used.

Performance Analysis of Microstriplines Interconnect Structure with Novel Guard Trace as Parallel Links for High Speed Dram Interfaces

Wireless communication have progressed so fast in recent years with the increased frequency of operation, faster signal speed, reduced feature size and increased the integration of analog and digital blocks within a constrained space. These made the signal integrity analysis is a challengine task to printed circuit board designers. The signal integrity effects need to be mitigated by the proper design of high speed interconnects. In order to reduce crosstalk and crosstalk induced jitter in high speed parallel links to DRAM interface, a novel parallel microstriplines with U shaped guard trace interconnect structure is proposed. The crosstalk performance of the proposed interconnect structure, it can be implemented in DRAM board and compared with the conventional guard intervening scheme. The proposed structure increased the maximum data rate from 800 Mbps to 3.3 Gbps and reduced CIJ more than 2 ps.

Traffic assignment: on the interplay between optimization and equilibrium problems

ABSTRACT Motorists often have to choose routes helping them to realize faster journey times. Route choices between an origin and a destination might involve direct main roads, shorter routes through narrow side streets, or longer but (potentially) faster journeys using motorways or ring-roads. In the absence of effective traffic control measures, an approximate equilibrium travel time may result between the routes available, which is generally expected to be far from optimal. In this paper, we investigate discrete and continuous optimization and equilibrium-type problems, for a simplified traffic assignment problem on a simple network with parallel links and fixed demand. We explore the interplay between solutions of certain optimization and equilibrium problems which can be solved by dynamic programming. The results are supported by numerical simulations, in which the price of anarchy is calculated to highlight the demand levels where there is a change in road choice and usage.

Calibration control to maintain US focal point accuracy and its application to parallel link robot

Calibration control to maintain US focal point accuracy and its application to parallel link robot

Calibration control to maintain US focal point accuracy and its application to parallel link robot

Calibration control to maintain US focal point accuracy and its application to parallel link robot

Design and prototype of a wearable fingertip tactile display using 6DoF parallel link mechanism

Design and prototype of a wearable fingertip tactile display using 6DoF parallel link mechanism

An Area-Efficient and Wide-Range Inter-Signal Skew Compensation Scheme With the Embedded Bypass Control Register Operating as a Binary Search Algorithm for DRAM Applications

The timing skew between signals reduces the timing margin of the receiver and limits the data rate of the parallel link. This issue becomes more critical for applications with many IO pins, such as a high bandwidth memory (HBM). The inter-signal skew compensation scheme for many IO pins requires not only de-skew performance but also the minimization of area and power overheads. In this brief, we propose an inter-pin skew compensation scheme using bypass-controlled all digital delay locked loops (ADDLL). The adoption of the proposed bypass control register that operates with a binary search algorithm, such as the successive approximation register (SAR), allows the digital control delay line (DCDL) controller to be embedded in the delay line. This can alleviate the limitation of bandwidth, which is a disadvantage of SAR and occupies smaller area than SAR whereas maintaining the fast lock time. The circuit is fabricated using a 28 nm CMOS technology with a 1 V supply voltage and an area of 0.0009 mm2 for one de-skew module. The measured result shows that inter-signal skew is reduced to less than 3 ps for 2 Gb/s/pin $\times8$ parallel signals.

The price of anarchy of affine congestion games with similar strategies

Affine congestion games are a well-studied model for selfish behavior in distributed systems, such as transportation and communication networks. Seminal influential papers in Algorithmic Game Theory have bounded the worst-case inefficiency of Nash equilibria, termed as price of anarchy, in several variants of these games. In this work, we investigate to what extent these bounds depend on the similarities among the players' strategies. Our notion of similarity is modeled by assuming that, given a parameter θ≥1, the costs of any two strategies available to a same player, when evaluated in absence of congestion, are within a factor θ one from the other. It turns out that, for the non-atomic case, better bounds can always be obtained for any finite value of θ. For the atomic case, instead, θ<3/2 and θ<2 are necessary and sufficient conditions to obtain better bounds in games played on general graph topologies and on parallel link graphs, respectively. It is worth noticing that small values of θ model the behavioral attitude of players who are partially oblivious to congestion and are not willing to significantly deviate from what is their best strategy in absence of congestion.

Coalitions in Routing Games: A Worst-Case Perspective

We investigate a routing game that allows for the creation of coalitions, within the framework of cooperative game theory. Specifically, we describe the cost of each coalition as its maximin value. This represents the performance that the coalition can guarantee itself, under any (including worst) conditions. We then investigate fundamental solution concepts of the considered cooperative game, namely the core and a variant of the min-max fair nucleolus . We consider two types of routing games based on the agents’ Performance Objectives, namely bottleneck routing games and additive routing games . For bottleneck games, we establish that the core includes all system-optimal flow profiles and that the nucleolus is system-optimal or disadvantageous for the smallest agent in the system. Moreover, we describe an interesting set of scenarios for which the nucleolus is always system-optimal. For additive games, we focus on the fundamental load balancing game of routing over parallel links. We establish that, contrary to bottleneck games, not all system-optimal flow profiles lie in the core. However, we describe a specific system-optimal flow profile that does lie in the core and, under assumptions of symmetry, is equal to the nucleolus.

Design Modification and Improvement on Automobile Suspension System

Now days the air suspension system is used in all commercial vehicles like buses and trucks. In the recent era the peoples are looking for Air suspension in Light Commercial Vehicles. The Air suspension system comprises of many brackets, from them we selected the parallel link bracket. The existing Parallel link bracket is consists of more number of supporting plates, tubes, welding and also it having more weight. This type of brackets ate mounted in vehicle chassis with the help of bolted joints. The weight of the Air Suspension System is more important in the aspect of vehicle mileage. All the major OEM's are pressurising for reducing the weight of the air suspension system. By assimilate the optimized process or process route, removing the unfavourable materials or processes and decreasing the number of parts in mandatory area, mean while without affecting the requirement of the component and also reducing the weight of the components or assembly.

Time Reversal Based MAC for Multi-Hop Underwater Acoustic Networks

Constrained-energy underwater acoustic nodes are typically connected via a multi-hop underwater acoustic network (MHUAN) to cover a broad marine region. Recently, protocols for efficiently connecting such nodes have received considerable attention. In this paper, we show that the time reversal (TR) process plays an important role in the medium access control (MAC) because of its physical capability to exploit the multi-path energy from the richly scattering underwater environment, as well as to focus the signal energy in both spatial and temporal domains. In MHUANs, with severe multi-path propagation at the physical layer, the active TR process spatially focuses the signals to the location of the intended receiver; this significantly diminishes the interference among parallel links. We propose an active TR-based MAC protocol for MHUANs, with the aim of minimizing collision and maximizing channel utilization simultaneously. Furthermore, by considering the impact of the cross-correlation between different links on the TR-based medium access, we derive the threshold of the link cross-correlation to resolve collision caused by the high cross-correlation between realistic links. We perform simulations using the OPNET and BELLHOP environments, and show that the proposed TR-based MAC results in significantly improved throughput, decreased delay, and reduced data drop ratio in MHUANs.

A Highly Reliable and Efficient Class of Single-Stage High-Frequency AC-Link Converters

This paper proposes a new class of topologies of single-stage high-frequency ac-link power converters, which is capable of providing both voltage step up/down within a wide frequency and voltage ranges. The proposed family, which supports bidirectional power flow, can interface various single/multi-port dc and/or single/multi-phase ac systems to provide dc–dc, dc–ac, ac–dc, or ac–ac power conversion. In this family of converter, which offers a very modular structure, a small inductor that forms the link exchanges power entirely or partially between the source and load. The proposed family can function in buck, boost, and/or buck–boost modes of operation, and a combination of these modes of operation is also feasible. In comparison to the parallel inductive four-quadrant link converters, the proposed family features a significantly reduced link peak current, reduced switch ratings, and reduced total number of power switches. These features enhance the efficiency, reduce the total cost, and increase the power density of the system. In order to further improve the overall efficiency of the system, minimize the current/voltage stress over all utilized semiconductor devices, and lower electromagnetic interference (EMI), a small capacitor is placed in parallel with the link inductor to realize soft-switching operation for the proposed configurations. Moreover, the proposed converters have the potential to incorporate a lightweight single-phase high-frequency transformer for electrical isolation. The proposed circuit topologies prevent reverse recovery issues and eliminate losses corresponding to body diodes of power switching devices via utilizing power switches in conjunction with external fast recovery diodes. The proposed family offers a very high level of reliability owing to its immunity from short circuit of input and output terminals and open circuit of the link inductor, which may occur in other power converters due to commutation problem resulting from a short deadtime or an overlap time between switches, unwanted control command, delay in electronic circuits, or EMI noise's misgating on or off , in addition to the absence of electrolytic capacitors in the power circuit. A control approach is also developed to regulate input and output currents in one stage of power conversion. A detailed theoretical analysis, operation, design methodology, and control strategy of the proposed family are provided in this paper, and the effectiveness and performance of the proposed converter family are verified via simulation results and experimentally.

Position Control of Parallel Active Link Suspension With Backlash

In this article, a position control scheme for the novel parallel active link suspension (PALS) with backlash is developed to enhance the vehicle ride comfort and road holding. A PALS-retrofitted quarter car test rig is adopted, with the torque flow and backlash effect on the suspension performance is analyzed. An elastic linear equivalent model of the PALS-retrofitted quarter car, which bridges the actuator position and the equivalent force between the sprung and unsprung masses, is proposed and mathematically derived, with both the geometry and backlash nonlinearities compensated. A position control scheme is then synthesized, with an outer loop H $_{\infty}$ control for ride comfort and road holding enhancement and an inner loop cascaded proportional-integral control for the reference position tracking. Experiments with the PALS-retrofitted quarter car test rig are performed over road cases of a harmonic road, a smoothed bump, and frequency swept road excitation. As compared to a conventional torque control scheme, the newly proposed position control maintains the performance enhancement by the PALS, while it notably attenuates the overshoot in the actuator's speed variation, and thereby it benefits the PALS with less power demand and less suspension deflection increment.

Design of parallel link mobile robot manipulator mechanisms based on function-oriented element base

To create effective mobile robot manipulators, a function-oriented element base is proposed. Element base selection is based on the analysis of schematics of mobile robot manipulators. It is substantiated that the effective schematics of manipulators are parallel link mechanisms. A rational structural scheme was adopted as a mechanism having six rods of variable length (hexapod). The schemes of mobile robot manipulators with different numbers and types of combined rod supports are considered. It is proved that the same type of element base in the form of spherical hinges can be used to implement a variety of schemes. Different embodiments of schematics of manipulators designed on the proposed function-oriented element base are considered. The basic requirements for the element base of mobile robot manipulators are defined. It is shown that the requirements are provided by the function-oriented element base on the basis of different hydrostatic or aerostatic hinges.A series of variants of schematics and design solutions of regulated spherical hydrostatic and aerostatic hinges are proposed. The hydrostatic spherical hinge, which includes an accurate ceramic (boron carbide) ball has high precision characteristics. Technological approbation of this schematic is conducted by manufacturing a production prototype.The regulated hydrostatic hinge is equipped with a mechatronic system for determining the spatial position of the sphere. This design solution allows you to adjust the position of the hinge sphere within the diametric clearance.The combined aerostatic-hydrostatic support unit aggregated with manipulator drives is proposed. The unit has a jet system for adjusting the support reactions of the aerostatic-hydrostatic supports of the spherical hinge. Technological testing of the developed device is carried out.In order to increase the efficiency of the proposed element base, special algorithms for controlling the position of the spherical manipulator hinges are developed. The algorithms are based on the mathematical modeling of dynamic processes in hinge devices. The algorithms include the implementation of spatial polyharmonic displacements of the sphere with the purposeful selection of the direction of the resulting displacements, which provides the necessary accuracy and speed of the process of adjusting the position of the manipulator.

Statistical Eye Diagram Analysis Based on Double-Edge Responses for Coding Buses

For high-speed coding buses, it is a great challenge to evaluate the eye diagram accurately. Assuming that all data bits are independent and have uniform probabilities as previous estimation methods have done is not valid. In this paper, a new statistical method is proposed to estimate the worst-case eye diagrams and bit-error-rate (BER) eye diagrams for coding buses. The probability distribution of coded bus bit vectors is modeled based on the coding rule constraints. Then, actual worst pattern and eye diagram calculation is derived based on bus bit transition probabilities and double-edge responses. In order to validate the method, a parallel link with data bus inversion coding and 4b/6b coding is simulated, respectively. Worst case eye diagrams and BER eye diagrams are calculated and compared with that of no consideration of coding. Compared to the traditional statistical methods, this method eliminates the error due to the invalid assumption and provides more accurate results for designers.

Generalized channel estimation and data detection for MIMO multiplexing FSO parallel channels over limited space

In this paper, to increase the data rate of free-space optical (FSO) links, we consider multiple parallel FSO links arranged over a specified space (transceivers arranged over two rings with specified radius). Due to its ease of implementation, stability, and low cost, intensity modulation with direct detection (IM/DD) based on On–Off-Keying (OOK) is widely employed in practical terrestrial FSO links. For long-haul FSO links, avalanche photo diodes (APDs) are commonly used, which provide an internal gain in photo-detection, allowing larger transmission ranges, as compared with PIN photo-detector counterparts. Over the considered general case, firstly, we propose maximum likelihood (ML)-based detection methods when the receivers are aware of the instantaneous channel fading coefficients (CSI). Secondly, we propose an efficient OOK data detection method for a more practical case when the instantaneous CSI is not available at the receiver. For this state, initially, the channel coefficients are estimated by employing some pilot symbols and then, we use the channel estimated coefficients to detect OOK signals. For a specified space, due to crosstalk between parallel channels and pointing errors, performance of proposed data detection methods depends on the optimum value for beam waist. By providing Monte-Carlo simulation results, the optimum value of beam waist is obtained for various channel conditions. To evaluate the BER performance, we also provide analytical results and derive an analytical expression for the considered MIMO multiplexing scheme. The validity of our analytical results are confirmed by Monte-Carlo simulations.

Hand Motion Measurement using Inertial Sensor System and Accurate Improvement by Extended Kalman Filter.

Analysis of hand motions is crucial in such actual conditions as daily life and traditional work. We developed a measurement system using inertial sensors instead of an optical motion capture system that measures with spatial constraints. However, for these sensors, the posture error caused by the integration of the angular velocity is critical. A typical solution uses sensor fusion with simple observation equations to measure such lower limbs by walking analysis. For finger motions, a simple observation, calculated identically as the initial posture, is unsuitable because fingers may be moved intricately and quickly by multiple joints and parallel links. Therefore, we constructed an observation equation based on such dynamic acceleration as rotational acceleration and the correction of compass error. Using this suggested observation equation, since both the posture and position error were verified in the hand and forearm motions by a comparison with the optical motion capture, we could measure them with high accuracy. After measuring the movements of an actual hand, such as writing words and spinning a top, we analyzed the characteristics from a reproduced link model and joint angles.