Platform Configuration Research Articles

Scalable Microfluidic Platform for Flexible Configuration of and Experiments with Microtissue Multiorgan Models.

Microphysiological systems hold the promise to increase the predictive and translational power of in vitro substance testing owing to their faithful recapitulation of human physiology. However, the implementation of academic developments in industrial settings remains challenging. We present an injection-molded microfluidic microtissue (MT) culture chip that features two channels with 10 MT compartments each and that was designed in compliance with microtiter plate standard formats. Polystyrene as a chip material enables reliable, large-scale production and precise control over experimental conditions due to low adsorption or absorption of small, hydrophobic molecules at or into the plastic material in comparison with predecessor chips made of polydimethylsiloxane. The chip is operated by tilting, which actuates gravity-driven flow between reservoirs at both ends of every channel, so that the system does not require external tubing or pumps. The flow rate can be modulated by adjusting the tilting angle on demand. The top-open design of the MT compartment enables efficient MT loading using standard or advanced pipetting equipment, ensures oxygen availability in the chip, and allows for high-resolution imaging. Every channel can be loaded with up to 10 identical or different MTs, as demonstrated by culturing liver and tumor MTs in the same medium channel on the chip.

Architecture and sedimentary evolution of the southwestern Gissar carbonate platform (Uzbekistan) during the Middle‒Late Jurassic

Abstract Sedimentological investigations have been carried out in the southwestern part of the Gissar Range (Uzbekistan) in order to document the stratigraphic evolution of a vast Middle–Upper Jurassic carbonate platform developed on the northern margin of the Amu Darya Basin. Two major sequences are distinguished, based on their contrasting facies pattern, platform configuration and carbon isotope signature: (1) a Callovian Sequence and (2) an Upper Jurassic Sequence, potentially Oxfordian to Kimmeridgian in age. A carbonate ramp with a double proximal-distal polarity developed during the Callovian Sequence. Oo-bioclastic grainstones were produced in two permanently agitated shallow water areas developing to the north and to the south. Patch and pinnacle reefs mainly built up close to the storm-wave base, passing distally to pellet- and foraminiferal-oncoid-rich mid-to outer-ramp deposits. The top of the Callovian Sequence is a regional discontinuity that could have formed by subaerial exposure of the platform. This probable hiatus could record a major climatic change associated to the Middle‒Late Jurassic transition. The Upper Jurassic Sequence consists of metre-thick alternations of pellet/algal-pack- to grainstones, microbial oncoid floatstones, ooid grainstones, and mudstones, which have likely accumulated in a vast lagoon protected by a large-scale barrier reef observed south of the study area. Gypsum and anhydrite content gradually increased towards the top of the Upper Jurassic Sequence, ending up with a thick chicken-wire gypsum accumulation recording the progradation of a large-scale sabkha over the lagoon. This phenomenon is related to a progressive aridification and restriction of the Amu Darya Basin that could have begun during the Middle/Late Oxfordian and reached its climax during the Tithonian with massive halite deposition. Comparable events occurred in Jurassic platforms located along the Tethyan margins, pointing to regional and global controls on sedimentation.

Game‐theoretic approach for the optimal configuration computing of an interoperable fleet of unmanned vehicles

AbstractThis paper investigates the problem of fleet configuration for a set of unmanned vehicles. Without the need of on‐board pilots, unmanned vehicles have proven to accomplish different types of missions both in military and civil domain. In addition, a multi‐vehicle fleet is able to guarantee better performances and minimum costs, as long as they are coordinated. In futuristic scenarios, it is conceivable to quickly identify the best team of unmanned vehicles to perform a given mission by considering all the appropriate means made available. Thus, the problem to guarantee the better platform configuration becomes identifying the best fleet. This work proposes a possible approach to process the best fleet of unmanned vehicles to perform an envelope of missions, by transforming the fleet configuration activity in an optimization problem under some basic hypotheses. The optimality of the fleet is meant with respect to the needed costs, which have to be minimized. The addressed concept envisages a distributed and decentralized planning to achieve a proper level of interoperability among different organizations that are involved in the fleet provision. The paper presents the formal definition of the problem and a game‐theoretic solution. In the end, preliminary simulation results are discussed.

Selection of computational environments for PSP processing on scientific gateways

Science Gateways have been widely accepted as an important tool in academic research, due to their flexibility, simple use and extension. However, such systems may yield performance traps that delay work progress and cause waste of resources or generation of poor scientific results. This paper addresses an investigation on some of the failures in a Galaxy system and analyses of their impacts. The use case is based on protein structure prediction experiments performed. A novel science gateway component is proposed towards the definition of the relation between general parameters and capacity of machines. The machine-learning strategies used appoint the best machine setup in a heterogeneous environment and the results show a complete overview of Galaxy, a diverse platform organization, and the workload behavior. A Support Vector Regression (SVR) model generated and based on a historic data-set provided an excellent learning module and proved a varied platform configuration is valuable as infrastructure in a science gateway. The results revealed the advantages of investing in local cluster infrastructures as a base for scientific experiments.

Privacy Protection Scheme Based on Remote Anonymous Attestation for Trusted Smart Meters

The emergence of smart grids has considerably improved the quality of life. However, the real-time electric usage information transmitted by smart meters reveals consumers’ private information. Based on the remote anonymous attestation technology in trusted computing, the concept of a trusted smart meter is proposed in this paper in order to protect consumers’ private information from the terminal end. Attribute certificates are used to hide the platform configuration of smart meters and the ring signature technology is adopted to hide users’ personal information. The proposed protocol not only prevents the leakage of private information with competitive efficiency but also ensures trusted detection for upgrading the software of smart meters.

Optimal morphing – augmented dynamic soaring maneuvers for unmanned air vehicle capable of span and sweep morphologies

This paper investigates autonomous dynamic soaring maneuvers for a small Unmanned Aerial Vehicle (sUAV) having the capability to morph. Dynamic soaring for UAVs have mostly been confined in literature to fixed configurations. In order to analyze the extent to which dynamic soaring is influenced by different morphologies, an innovative concept of integrating dynamic soaring with morphing capabilities is introduced. Moreover, optimal soaring trajectories are generated for two basic wing morphologies: variable sweep and variable span. Three-dimensional point-mass UAV equations of motion and nonlinear wind gradient profile are used to model the flight dynamics. Parametric characterization of the key performance parameters is performed to determine the optimal platform configuration during various phases of the maneuver. Results presented in this paper indicate 15% lesser required wind shear by the proposed span morphology and 14% lesser required wind shear by the proposed sweep morphology, in comparison to their respective fixed wing counterparts. This shows that the morphing UAV can perform dynamic soaring in an environment, where fixed configuration UAVs might not, because of lesser available wind shears. Apart from this, span morphology reduced drag by 15%, lift requirement by 11% and angle of attack requirement by 20%, whereas increased the maximum velocity by 6.2%, normalized energies by 9% and improved loitering parameters (approximately 10%), in comparison to fixed span configurations. Similarly, sweep morphology guaranteed 20% drag reduction, 16% lesser angle of attack requirement and improved loitering performance over the fixed sweep configurations. The results achieved from this study strongly support the idea of integrating dynamic soaring with morphing capabilities and its potential benefits.

Finite Element Analysis and Experimental Simulation of Chassis Mounted Platform for Off-Road Wheeled Combat and Transport Utility Vehicles

Chassis mounted platform is an intermediate component between vehicle chassis and chassis mounted shelter, and is intended to act as a levelled base for shelters. Shelters in combat vehicles provide a closed stipulated environment to computerized tracking systems, sophisticated defense combat equipments to suit the operational and environmental requirements during warhead situations. Platform carries transfers and sustains unevenness in load arising from the road or soil irregularities during off-road vehicle travel. Present work deals with development, evaluation and improvement of one such platform for 8x8 vehicles. In this work, the platform under consideration is designed to accommodate two shelters, each being secured to the platform using standard twist locking arrangements. Securing locations are dependent on the size and weight of the commodity to be placed inside shelter. Major design ruminations of the platform include nature and pattern of load, flange orientations of channel sections, span between webs of consecutive channels, axle load distribution and vehicle geometry constraints as ground clearance and departure angle. Finite element analysis is carried out in to order evaluate stress and deflection in the present platform configuration. Experimental strain measurement at critical locations on the platform is carried at Automotive Research Association of India (ARAI) to evaluate the performance of the platform under specified load-speed conditions. Relation between experimental stress values and strain gauge locations on the platform is assessed for different load magnitudes.

The platformization of cultural production: Theorizing the contingent cultural commodity

This article explores how the political economy of the cultural industries changes through platformization: the penetration of economic and infrastructural extensions of online platforms into the web, affecting the production, distribution, and circulation of cultural content. It pursues this investigation in critical dialogue with current research in business studies, political economy, and software studies. Focusing on the production of news and games, the analysis shows that in economic terms platformization entails the replacement of two-sided market structures with complex multisided platform configurations, dominated by big platform corporations. Cultural content producers have to continuously grapple with seemingly serendipitous changes in platform governance, ranging from content curation to pricing strategies. Simultaneously, these producers are enticed by new platform services and infrastructural changes. In the process, cultural commodities become fundamentally “contingent,” that is increasingly modular in design and continuously reworked and repackaged, informed by datafied user feedback.

A six degree of freedom passive vibration isolator with quasi-zero-stiffness-based supporting

A six degree of freedom nonlinear passive vibration isolator is proposed based on Stewart platform configuration with the quasi-zero-stiffness structure as its legs. Due to the high static stiffness and low dynamic stiffness of each leg, the proposed six degree of freedom system can realize very good vibration isolation performance in all six directions while keeping high static load-bearing capacity in a pure passive manner. The mechanic model of the proposed six degree of freedom isolator and the dynamic equation of the isolator are established successively. Theoretical analysis on cross coupling stiffness reveals that the system can demonstrate quasi-zero-stiffness property in all six degree of freedom. Moreover, an analysis on stability shows that the condition of structural parameters for the isolator to realize quasi-zero-stiffness is also the stability boundary of the system. A series of numerical simulations on displacement transmissibilities in coupled degree of freedoms, the coupling effects of transmissibility, and a dynamic response in random excitation are carried out to show the effectiveness of the proposed six degree of freedom isolator, as well as the influence of structural parameters on vibration attenuation performance. Considering its high performance in a simple passive manner, it can be foreseen that the proposed six degree of freedom isolator will be applied in various engineering practices with multi-degree of freedom vibration isolation.

Best practices for underplatform damper designers

The purpose of this paper is to offer a practical demonstration of how essential preoptimization is in the design of underplatform dampers for turbine blades. Preoptimization can be thought of as a “prescreening” which allows excluding, since the early design stages, a high number of poorly performing damper–platform configurations. This concept, previously presented by the authors, is here extended and its generality for all blade bending modes is rigorously demonstrated. The paper addresses a test case where the introduction of curved-flat underplatform dampers is necessary to avoid a dangerous resonance crossing in the operating rotational speed range of a real turbine disk. It is shown how preoptimized dampers are the only ones that manage to satisfy all functional requirements, including those in the nonlinear operating regime. The same set of dampers may have been identified by exploring, through hundreds of computationally intensive nonlinear calculations, the performance of all possible damper configurations. The latter approach, i.e. iterative design, is unpractical and has to be repeated for each new set of blades since it is based on a test case-specific trial-and-error procedure. Preoptimization substitutes iterations with knowledge of the damper behavior and can therefore be considered as “informed design”: viable damper configurations are instantly singled out through simple but insightful considerations on the damper equilibrium of forces and moments.

UAS as flexible and innovative test platform for aircraft configuration and systems testing

Today new technologies are available, which can be decisive for the success of future aircraft design. However, the gap between conventional designs and new visions often comes with a high financial risk. This complicates the integration of innovations significantly. The “Flightpath 2050 Europe’s Vision for Aviation” asks for new aircraft concepts and configurations to meet future requirements such as emission (CO2, NOx), noise and fuel consumption reduction. Scaled UAS are one way for getting new configurations and technologies into flight test while reducing the risk of exploding costs. UAS are cost-efficient test platform systems for two main tasks of future aircraft tests: Testing new configurations and advancing new aircraft systems and technologies from upstream research to TRL5-6. UAS can represent a connection between innovative research and flight demonstration. This paper focuses on the UAS as an innovative test platform and a tool for feasibility demonstration as well as its impact on new technologies and the implementation of innovative concepts. An example of a UAS test platform is given in the paper based on a 33,3% scale model of the e-Genius. It is developed as flying wind tunnel in order to better understand the effects of configuration changes on flight performance.

The Kinematics, Dynamics and Control of a Flying Parallel Robot With Three Quadrotors

This letter deals with a novel flying mechanism. Inspired from parallel manipulators, this flying robot is composed of three quadrotors linked by a rigid articulated architecture composed of three legs and a platform. Associating quadrotor comanipulation and rigid bodies, this new design offers novel possibilities for aerial robotics and manipulation. Previous work leads to the design of a flying parallel robot with two quadrotors. However, this robot did not allow the full control of the six degrees of freedom of its end-effector. With an additional quadrotor, this study seeks to obtain a full control of the platform position and orientation. To prove this property, the kinematic constraints are verified through screw theory. Then, the dynamic model is established and a decoupling property leads to the design of a specific controller for the platform and legs configurations. ADAMS/SIMULINK cosimulations validate the theoretical developments.

Multiagent-Based Flexible Edge Computing Architecture for IoT

This article presents a proposal for FLEC architecture, which solves problems resulting from the rigidity of the traditional IoT architecture and edge computing. FLEC architecture is a flexible and advanced IoT system model characterized by environment adaptation ability and user orientation ability. We utilize COSAP, a system configuration platform based on a multiagent framework, as an implementation procedure for FLEC architecture. Furthermore, this article presents its application case study of a healthcare support system for a sports event with many participants. Finally, we demonstrate the contribution of this proposed architecture to problem solution in edge computing.

A Flexible Laboratory Environment Supporting Honeypot Deployment for Teaching Real-World Cybersecurity Skills

In the practical study of cybersecurity, students benefit greatly from having a full control of physical equipment and services. However, this presents far too great a risk to security to be permitted on university campus networks. This paper describes an approach, used successfully at Northumbria University, in which students have control of an off-campus network laboratory, with a dedicated connection to the Internet. The laboratory is flexible enough to allow the teaching of general purpose networking and operating systems courses, while also supporting the teaching of cybersecurity through the safe integration of honeypot devices. In addition, this paper gives an analysis of honeypot architectures and presents two in detail. One of these offers students the opportunity to study cybersecurity attacks and defences at very low cost. It has been developed as a stand-alone device that can also be integrated safely into the laboratory environment for the study of more complex scenarios. The main contributions of this paper are the design and implementation of an off-campus, physical network laboratory; a small, low-cost, configurable platform for use as a “light-weight” honeypot; and a laboratory-based, multi-user honeypot for large-scale, concurrent, cybersecurity experiments. This paper outlines how the laboratory environment has been successfully deployed within a university setting to support the teaching and learning of cybersecurity. It highlights the type of experiments and projects that have been supported and can be supported in the future.

On-board visual navigation system for unmanned aerial vehicles autonomous aerial refueling

In this paper, an on-board binocular visual navigation system based on unmanned aerial vehicles platform is designed for autonomous aerial refueling. The hardware configuration of the entire platform is introduced. Vision algorithms including target tracking, feature extraction, and pose estimation are employed for measuring the relation between two unmanned aerial vehicles. Two situations are considered under long and short distances to make this procedure flexible. Four pose estimation algorithms are implemented and compared in this research. A series of experiments are conducted to verify the feasibility and effectiveness of aerial refueling on the unmanned aerial vehicle platform.

A New Family of Symmetrical 2T2R Parallel Mechanisms Without Parasitic Motion

This paper focuses on parallel mechanisms (PMs) that can perform two translations and two rotations (2T2R). Two sufficient conditions for eliminating parasitic motion in 2T2R PMs are presented. A motion expression satisfying those two conditions is identified and several kinematic bonds containing that motion are found. To achieve symmetrical structures, a configurable platform that generates an instantaneous translation motion is presented, to which four limbs having identical structures are connected, leading to the construction of novel 2T2R PMs. Several designs that may have good practical values are identified and form a mechanism family. A typical mechanism is selected with its position model, workspace, singularity thoroughly investigated. Redundant limbs are added to eliminate the singularities, which then ensure the rotational capability. The proposed mechanisms have the advantages of identical limbs, no parasitic motion, and relatively high rotational capability, which can be used in several applications such as in five-axis machine.

Investigation of single and twin jet interactions with plates with cut-outs

The design and testing of the launch vehicle structure and its subsystems to withstand the lift-off acoustic loads is quite a daunting task in itself. Any effort to minimize these loads can prove to be highly beneficial as it directly influences the design, weight, and qualification of the launch vehicle components and hence the overall vehicle operating cost and time. The components of launch pad such as the launch platform and jet blast deflector are known to be the principal noise sources of the intense acoustic loads generated during lift-off. They contribute to the overall noise levels experienced by the launch vehicle by either reflecting the noise generated by the jet exhaust or by creating additional sources of noise. Earlier studies showed that the presence of cut-outs in the launch platform significantly affects the overall acoustic loads experienced by the launch vehicle. The present paper attempts to characterize the influence of cut-outs in the launch platform on the noise levels experienced by the launch vehicle, by investigating single and twin jets impinging on flat plates with and without cut-outs at varying lift-off distances. The results from acoustic measurements carried out in the near and far-field of scaled down single and twin jet launch vehicle models are discussed. The paper also attempts to relate changes in acoustic field, brought about by the different platform configurations, to the changes in flow field through flow visualization using the schlieren technique.

Lifetime Test Design for Second-Use Electric Vehicle Batteries in Residential Applications

This paper provides a comprehensive study on the lifetime test design of second-use electric vehicle plug-in hybrid electric vehicle ((PHEV)/hybrid electric vehicle(HEV)/battery electric vehicle(BEV)) batteries as the residential application. The work starts by modeling a realistic operation environment for the second-use batteries. As a residential application, the battery pack usage profile was simulated in detail with proposed steps and parameters. The paper then presents design procedures for transferring simulated battery pack usage profile into a lifetime test profile. Finally, a lifetime test case study is performed on a second-use PHEV (Ford C-max) battery pack. The extraction of the residential application usage profile, the configuration of the test platform, and the 150-h demonstration test results together explain the proposed test methodology.

Aerodynamic influences on a tethered high-altitude lighter-than-air platform system to its behavior

The goal of this study was to investigate the influence of aerodynamic factors on the static behavior of a tethered high-altitude lighter-than-air platform. The system design comprised a lighter-than-air vehicle and a tether cable, and the conceptual platform configuration of such a system is studied herein. Governing equations were derived to model the static behavior of the system, and the effects of aerodynamic lift and buoyancy were parametrically analyzed based on the advection distance of the platform under storm conditions. The aerodynamic lift and buoyancy of the hull were shown to have nonlinear effects. We further analyzed the influence of the aerodynamic drag created by the tether. Since this was shown to have a significant influence, we concluded that the cable should ideally have a cross-sectional shape resembling the airfoil of a heavier-than-air aircraft. However, it is sufficient to ensure that the drag coefficient is of the order of 10−1.

Synthesis of conformal array antenna for hypersonic platform SAR using modified particle swarm optimisation

The synthetic aperture radar (SAR) system equipped on the hypersonic platform in the near space presents many advantages compared with the conventional airborne SAR. However, due to the complex aerodynamic configuration and flight characteristics of the hypersonic platform, the radar design is facing some new challenges. Taking into account the new features of the platform, in this study the authors analyse the conformal design requirements of the array antenna, as well as the prominent contradiction between the high resolution and wide swath of SAR. After establishing the model of the conformal array antenna and the space coordinate system of the far-field radiation, a specific process of synthesising the antenna pattern is given. Furthermore, the antenna mask templates of optimising the antenna pattern are generated based on the main performance measures of the SAR system, and the modified meta particle swarm optimisation algorithm is exploited to obtain the optimal excitation phase of each array element in synthesising the ultimate antenna pattern. Finally, simulation results verify the effectiveness of the method, where the performance of the optimised antenna pattern is evaluated numerically.