Platform Configuration Research Articles

A Modular Millifluidic Platform for the Synthesis of Iron Oxide Nanoparticles with Control over Dissolved Gas and Flow Configuration.

Gas–liquid reactions are poorly explored in the context of nanomaterials synthesis, despite evidence of significant effects of dissolved gas on nanoparticle properties. This applies to the aqueous synthesis of iron oxide nanoparticles, where gaseous reactants can influence reaction rate, particle size and crystal structure. Conventional batch reactors offer poor control of gas–liquid mass transfer due to lack of control on the gas–liquid interface and are often unsafe when used at high pressure. This work describes the design of a modular flow platform for the water-based synthesis of iron oxide nanoparticles through the oxidative hydrolysis of Fe2+ salts, targeting magnetic hyperthermia applications. Four different reactor systems were designed through the assembly of two modular units, allowing control over the type of gas dissolved in the solution, as well as the flow pattern within the reactor (single-phase and liquid–liquid two-phase flow). The two modular units consisted of a coiled millireactor and a tube-in-tube gas–liquid contactor. The straightforward pressurization of the system allows control over the concentration of gas dissolved in the reactive solution and the ability to operate the reactor at a temperature above the solvent boiling point. The variables controlled in the flow system (temperature, flow pattern and dissolved gaseous reactants) allowed full conversion of the iron precursor to magnetite/maghemite nanocrystals in just 3 min, as compared to several hours normally employed in batch. The single-phase configuration of the flow platform allowed the synthesis of particles with sizes between 26.5 nm (in the presence of carbon monoxide) and 34 nm. On the other hand, the liquid–liquid two-phase flow reactor showed possible evidence of interfacial absorption, leading to particles with different morphology compared to their batch counterpart. When exposed to an alternating magnetic field, the particles produced by the four flow systems showed ILP (intrinsic loss parameter) values between 1.2 and 2.7 nHm2/kg. Scale up by a factor of 5 of one of the configurations was also demonstrated. The scaled-up system led to the synthesis of nanoparticles of equivalent quality to those produced with the small-scale reactor system. The equivalence between the two systems is supported by a simple analysis of the transport phenomena in the small and large-scale setups.

A Gough–Stewart parallel manipulator with configurable platform and multiple end-effectors

This work describes a novel robot manipulator with configurable platform. Three internal degrees-of-freedom are added for controlling the relative orientation of the terminal links supporting multiple end-effectors of a Gough–Stewart-type parallel manipulator. The instantaneous forward and inverse kinematic analyses of the robot are derived using the theory of screws. Furthermore, the exploitation of this approach for deriving the acceleration analyses of a parallel manipulator with configurable platform is novel in this research field. As an intermediate step the forward and inverse displacement analyses are also investigated. A numerical example is compared with the outcome of a commercial software demonstrating the approach correctness.

Precise Internal Calibration Scheme for Very-High Resolution SAR System and Its Airborne Campaign Results

For future ultra-high resolution spaceborne SAR missions, large beam-steering capability and large antenna aperture are demanded to increase the azimuth resolution and to maintain the sensor sensitivity simultaneously. Thus, large-deployable antenna is a desirable option as compared with planar array antenna for these missions, since it is advantageous in terms of mass, size, and cost. Moreover, its antenna pattern will not have any distortion with mechanical beam-scanning approach. In this paper, a novel reflector SAR system, including its platform configuration, attitude maneuvering strategy as well as SAR payload electronics are presented in detail. Furthermore, the key technique of very-high resolution SAR-internal instrument calibration scheme is also provided so as to remove the imbalance among channels to guarantee coherency and then to extract the range replica consequently. In the end, a carried-out airborne flight campaign is described and its imaging results are presented to validate the effectiveness of our system as well as calibration approach.

Wristwatch-Style Wearable Dielectric Resonator Antennas for Applications on Limps

A wristwatch-style wearable dielectric resonator antenna (DRA) is proposed for the 2.45-GHz ISM band and sub-6 GHz 5G NR bands around 2.5 GHz, such as the commercial band for China Mobile Communications Corporation. The antenna is designed for applications on forearms and ankles. Practical concerns, including the aligning method, platform size, specific absorption rate, and user effects are investigated. Coplanar feeding structure is applied for alignment and isolation. Analysis of the watchband-like substrate is highlighted to avoid performance degradation. Given that platform configurations are not discretionary in actual devices, parasitic loading is introduced to attain desirable substrate effects and suppress unwanted ones. The user-device interplay is studied in light of actual application scenarios. The specific absorption rate is calculated through multilayer biological tissue models. Meanwhile, radiation variation caused by users is estimated based on human phantom models and measurements.

Hybrid Simulation Framework for Multi-hazard Testing

The design of complicated structures which, under accidental actions, have to fulfill a certain performance level, has been a scientific challenge with social and economic implications, particularly in the field of earthquake engineering. Experimental testing on structures would shed light to the deriving issues, however the full-scaling requirements of the specimens and the most out of date existing laboratory facilities do not facilitate it. For that reason, it is generally proposed the testing structure to be decomposed in its components and the part of scientific interest can be laboratory tested, whereas the other substructures are analytically modelled. That approach is known as hybrid simulation method (HS) and lends itself as an efficient tool in unveiling the nonlinear response of structural systems, especially when testing in full-scale is sought. The present research aims to evaluate the technical aspects of implementing a robust, advanced hybrid simulation (HS) platform, based on technological advancements and combining user friendliness and effectiveness. In addition, the capabilities of the advanced platform pave the way to future research extensions towards studying multi-physics problems beyond the field of earthquake engineering. The good performance of the updated hardware configuration of the new platform was evaluated via a series of verification tests on a pinned steel cantilever column subjected to lateral loading in its elastic and inelastic response region and finally, making use of the advanced application platform as a whole, a hybrid simulation test was carried out on an industrial piping system under earthquake excitation.

A triangular 3D coordinate system for multilevel SVPWM generation

This article presents a triangular coordinate system, a three-dimensional (3-D) coordinate system in which the three axes are oriented at 60° to each other. The 3-D representation of multilevel inverter voltage space vectors and generation of 3-D space vector pulsewidth modulation (3DSVPWM) using this coordinate system is proposed. The proposed 3DSVPWM method offers advantage of simplicity, amenable for implementation in field programmable gate arrays (FPGA) and application specific integrated circuits (ASICs), and flexibility for common-mode voltage control. The existing methods for 3DSVPWM generation operate on a 3-D space, with the axes oriented at 90°. The conventional 3DSVPWM methods require switching among four vectors, located at vertices of a tetrahedron, in a PWM cycle. In addition, the triangular coordinate system offers flexibility to directly extend any two-dimensional SVPWM (2DSVPWM) algorithm to 3-D, since it also involves switching of three vectors located at vertices of a triangle. The proposed method of 3DSVPWM generation is generalized and can be extended to any n-level inverter. The three vectors switched to approximate the reference vector and their corresponding durations are directly determined utilizing arithmetic operations. The coordinate system and the generation of SVPWM utilizing the triangular coordinate system is explained and experimentally validated on a dSPACE DS1104 platform for a five-level open-end winding inverter configuration and results are presented.

ВИЗНАЧЕННЯ СТРУКТУРИ МОДУЛЬНОЇ ГУСЕНИЧНОЇ ПЛАТФОРМИ БАГАТОФУНКЦІОНАЛЬНОГО БЕЗПІЛОТНИКА

The concept of a caterpillar platform for drones for various purposes based on the "modular" approach is proposed. The “modular” approach provides for the design of the supporting platform (housing, consisting of several modules of the same design as the old parts) and individual suspension modules (balancer - hydropneumatic spring - track roller). Traditional caterpillar mover (caterpillar, drive and guide wheels, track tension mechanism, track and support rollers). The concept of the platform design includes the possibility of changing the spatial position of the hull by adjusting the suspension moves and the caterpillar contour (on both sides). Changing the position of the casing and the geometry of the caterpillar contour is carried out synchronously by using a hydraulic control system in the suspension and in the hydraulic tension mechanism. The proposed platform configuration consists of two main modules: 1-body, 2-chassis. Platform module 1 (housing) consists of three modules: power, track control and suspension, payload (located between the power module and the control module). Module 2 of the platform consists of two modules: suspension (set of individual suspensions of both sides) and tracks

IEEE Access Special Section Editorial: Trusted Computing

Trusted Computing (TC) is a technology developed and promoted by the Trusted Computing Group (TCG), and aims to enhance the overall security, privacy and trustworthiness of a variety of computing devices. The core of the trusted computing technologies of TCG is the Trusted Platform Module (TPM), a tamper-resistant module embedded in a platform, which is implemented by a TPM chip and designed to resist software attacks and moderate hardware attacks. TPM includes non-volatile storage, a set of Platform Configuration Registers (PCRs) and an engine for cryptographic operations. Based on TPM and TCG Software Stack (TSS), a suite of mechanisms can be realized, including memory curtaining, protected execution, secure I/O, sealed storage, platform measurement and remote attestation. As a fundamental secure computing module, TPM is the root trust module to establish security and trust in digital computing, communication and networking. Basically, it can support secure booting and trustworthy software installation, private data protection and Digital Rights Management (DRM), as well as remote attestation- based trusted communications and collaboration. There is significant research currently in the field of trusted computing, in both academia and industry. Recent efforts focus on TC module development and extension, trustworthy software assurance, Trusted Execution Environment (TEE), trusted collaboration and trusted storage. The recent advance of Intel Software Guard Extensions (Intel® SGX) offers hardware-assistant TEE, which allows user code execution in a private region of memory, called enclave, in an untrusted third party. This technology attracts special attention and motivates innovations of many applications.

Multi-Degree of Freedom Isolation System With High Frequency Roll-Off for Drone Camera Stabilization

The technological developments in the field of image based sensing have led to a vast growth in the use of drones in various domains. The drone is usually equipped with an image sensor (camera) which collect images over the target area. These images are then post-processed to extract the important information. Efficiency and accuracy of the image based sensing are largely dependent on the captured image quality. Therefore, it is important to prevent the transmission of the drone vibrations to the camera. Most of the current camera mounting systems use passive rubber mounts for isolation. However, these mounts are effective only in vertical direction and essentially adds damping to the system which degrades the performance of the isolation at high frequency. In this paper, a multi-degree of freedom isolation system, based on a Stewart platform configuration, is proposed for drone camera stabilization. The important features of the proposed isolation system are — (i) high frequency roll-off, (ii) no use of flexible joints, (iii) uses non-contact voice coil actuator thus avoiding spurious resonances of the legs, (iv) adjustable stiffness, (v) 3D printed lightweight parts and (vi) centralized control using a single sensor (inertial measurement unit). A prototype of the proposed system has been manufactured and validated experimentally. The proposed isolation system is found to reduce the response of the isolation system near resonance without compromising performance at high frequency. The application of the isolation system can be easily extended to other fields which require high quality image acquisition.

Analysis of a passive scissor-like structure isolator with quasi-zero stiffness for a seating system vibration-isolation application

It is widely known that vibration is a mechanical motion phenomenon where a mass point oscillates around an equilibrium point. Vibrations are a source of discomfort and are extremely harmful to vehicle drivers and passengers. The motivations of this research are to develop an innovative vehicle seating suspension system to isolate vibrations transmitted to vehicle drivers and passengers and to improve ride comfort to ensure that their health is not negatively impacted and to improve the working efficiency of the driver. An innovative design of a passive multi-degree-of-freedom vibration isolator is presented in a truck seat suspension system where a Stewart platform configuration with a six-degree-of-freedom (6-DOF) isolation system is used rather than the traditional Stewart platform. A scissor-like structure (SLS) is used as one of the supporting legs to provide a nonlinear system with quasi-zero stiffness (QZS). Vibration is effectively attenuated without a loss of the system's load capacity. The effects of structural parameters in the proposed system are studied to determine how to adjust the parameters to achieve better vibration-isolation performance. The results reveal that a SLS supporting leg with a small assembly angle, more layers, a shorter link length and less spring stiffness has led to better vibration isolation and higher system stability than the conventional baseline supporting structure.

Analysis of a passive scissor-like structure isolator with quasi-zero stiffness for a seating system vibration-isolation application

It is widely known that vibration is a mechanical motion phenomenon where a mass point oscillates around an equilibrium point. Vibrations are a source of discomfort and are extremely harmful to vehicle drivers and passengers. The motivations of this research are to develop an innovative vehicle seating suspension system to isolate vibrations transmitted to vehicle drivers and passengers and to improve ride comfort to ensure that their health is not negatively impacted and to improve the working efficiency of the driver. An innovative design of a passive multi-degree-of-freedom vibration isolator is presented in a truck seat suspension system where a Stewart platform configuration with a six-degree-of-freedom (6-DOF) isolation system is used rather than the traditional Stewart platform. A scissor-like structure (SLS) is used as one of the supporting legs to provide a nonlinear system with quasi-zero stiffness (QZS). Vibration is effectively attenuated without a loss of the system's load capacity. The effects of structural parameters in the proposed system are studied to determine how to adjust the parameters to achieve better vibration-isolation performance. The results reveal that a SLS supporting leg with a small assembly angle, more layers, a shorter link length and less spring stiffness has led to better vibration isolation and higher system stability than the conventional baseline supporting structure.

Value analysis for customizable modular product platforms: theory and case study

Mass customization and product platform design can exploit the benefits of modularity and provide personalized devices at competitive costs through economies of scope. However, customization-intense platforms can have thousands of potential configurations, whose development and verification must be prioritized. This paper develops a value analysis methodology that is able to rank alternative platform configurations according to customers’ preferences. It introduces Logit value, a definition of value based on a well-known stated choice model and explains the five steps of platform-based value analysis. Since product platforms are complex technical systems, particular attention is given to the gathering of information, the automatic generation of platform architectures and the visualization of results. A case study based on Google ARA’s Spiral-2 modular smart phone concept demonstrates an application of the methodology and shows its potential benefits. The case study leverages data from a conjoint analysis and survey of 200 potential customers in Puerto Rico and a generated set of over 21,000 potential configurations of which less than 1% are shown to be non-dominated. The value analysis identifies module types that are compatible with the modular product platform and appear in a high percentage of Pareto architectures. Knowledge pertaining to non-dominated configurations can provide insights into module development strategy and verification/validation activities.

Intelligent Real-time 3D Configuration Platform for Customizing E-commerce Products

Intelligent Real-time 3D Configuration Platform for Customizing E-commerce Products

O processo de construção do corpus de referência em Ciência da Informação

Objetivo: O presente trabalho propõe e aplica um percurso metodológico para a construção de corpus de referência na área de Ciência da Informação. Método: A metodologia da pesquisa pode ser classificada como exploratória, empírica e estudo de caso. Para a pesquisa foi delimitado o uso do corpus composto por 60 artigos selecionados por Souza (2005) e a adoção do Tesauro Brasileiro de Ciência da Informação (TBCI) como linguagem de indexação. O percurso metodológico proposto consistiu da adaptação de um modelo colaborativo de indexação social, assim como a elaboração de uma política de indexação social e a configuração e uso de um software para a construção de uma folksonomia assistida por grupos de usuários. A folksonomia assistida foi então analisada visando à compilação do corpus de referência. Resultado: O modelo colaborativo de indexação social foi obtido por meio da configuração da plataforma de gerenciamento de coleção denominada Tainacan, mais especificamente na configuração e preparação de uma coleção no software. Foi desenvolvida uma política de indexação social assistida e houve instrução aos grupos de usuários indexadores de forma a guiá-los no processo de indexação. A análise da folksonomia resultante se deu mediante comparação dos termos com as palavras-chave dos autores e com termos do TBCI, permitindo a posterior correção e exclusão de termos inadequados na compilação do corpus. Conclusões: Conclui-se que o percurso metodológico proposto se mostra eficaz na construção de corpus de referência no âmbito da Ciência da Informação.

Ecosystem for the deployment and management of virtual laboratories based on the standard IMS LTI

The advancement of information and communication technologies occurs due to the evolutionary capacity of computer equipment as well as the existence of increasingly sophisticated tools and applications. Virtual laboratories, a flexible tool which allows to design, simulate, model and test through experimentation real-life processes, are an example. Virtual laboratories have a great impact on engineering as they improve accessibility to experiments, facilitating the development of strategies in the field of education; they include interactive ways to observe, illustrate, demonstrate and investigate, aside from support system users in the elaboration and exchange of results. For this reason, the experience reflected in this article highlights the design and implementation of an ecosystem for the deployment and management of virtual laboratories, based on the IMS Learning Tools Interoperability standard. In this process, the methods and technologies applicable to the development of virtual laboratories are characterized with an instructional model for experimental environments that identifies the scope of the procedure and the technical criteria, taking into account LabManager, WebLabDeusto and LMS Sakai, and finally the installation and configuration of the cloud platform and the laboratory prototype that responds to the proposed ecosystem.

Government as a platform, orchestration, and public value creation: The Italian case

E-Government literature has discussed how the adoption of the Government as a Platform (GaaP) can help public administration to produce more efficient public services. However, since little attention has been given to the impact of GaaP on public value creation more research is needed to analyse whether the GaaP is effective to help the government to deliver public services that fulfil social expectations and, hence, public value. Indeed, efficiency does not guarantee public value. Besides efficiency, public value incorporates citizens' variegated expectations and needs that change over time and that are sometimes rival. For these reasons, the delivery of public value is often challenging for public agencies. The aim of this paper is to explain how the GaaP configuration can help public administration to deliver public value better. The paper finds that the modularity of the platform configuration and different ecosystems that support public agencies need to be orchestrated to support the effective creation of public value. The authors analyse the case of the Italian GaaP initiative to discuss the importance of the orchestration of the GaaP characteristics to improve the coordination among public agencies and enable the co-production of services with external actors, in order to deliver public value better. The findings show that the orchestration of the GaaP configuration characteristics can enable Italian public administration to deliver public value, but also that, if the GaaP is not properly orchestrated, it can constrain the creation of public value.

A Parallel Manipulator with Planar Configurable Platform and Three End-Effectors

This work reports on the kinematic analysis of a planar parallel manipulator endowed with a configurable platform assembled with six terminal links serially connected by means of revolute joints. This topology allows the robot manipulator to dispose of three relative degrees of freedom owing to the mobility of an internal closed-loop chain. Therefore, the proposed robot manipulator can admit three end-effectors. The forward displacement analysis of the configurable planar parallel manipulator is easily achieved based on unknown coordinates denoting the pose of each terminal link. Thereafter, the analysis leads to twelve quadratic equations which are numerically solved by means of the Newton homotopy method. Furthermore, a closed-form solution is available for the inverse position analysis. On the contrary, the instantaneous kinematics of the robot manipulator is investigated by means of the theory of screws. Numerical examples are included with the purpose to illustrate the method of kinematic analysis.

Focusing Hypersonic Vehicle-Borne SAR Data Using Radius/Angle Algorithm

As a transition platform between aircraft and satellite, hypersonic vehicle-borne (HSV) synthetic aperture radar (SAR) could offer many advantages such as strong survival ability, fast response, and wide detection range. However, due to the complex aerodynamic configuration and flight characteristics of the hypersonic platform, the HSV SAR faces new challenges including serious cross-couplings and spatial variations. In order to deal with these issues, a radius/angle algorithm (RAA) is devised, which has a similar processing flow as that of the conventional polar format algorithm (PFA). In the RAA, a novel 2-D interpolation function, similar to that of the PFA which is performed in the Cartesian coordinates, is derived in the curvilinear coordinate system. Due to the high accuracy of the multi-decomposition by using the polar radius and polar angle, the RAA has a much larger depth-of-focus than that of the PFA. Moreover, the RAA approach is insensitive to the height variations for the HSV SAR with curved trajectory flight, whereas the PFA is not because of the out-of-plane projection effect. Simulation results verify the effectiveness of the proposed approach.

Remote Parkinson's disease monitoring system: from smartphone to cloud platform

Parkinson's disease (PD) is a slowly progressive disorder that affects movement, muscle control, and balance. The earlier treatment can prevent the disease from developing and to prolongate the diseases prodromal phase. In this context, home monitoring services are potentially powerful tools for remote diagnosis and can improve healthcare services. Tremor is the most common symptom of a PD disorder and it has several advantages for continuous PD symptoms monitoring. The developing of solution based on smartphone sensors that allow remote monitoring of the monitored user is present. The connection between the smartphone application and cloud platform for smartphone sensors data transmission for early tremor symptoms detection is developed. It includesdeveloping of configuration of smartphone application for sensor data transmission and developing of configuration of a cloud platform for tremor symptoms monitoring. The active tests were developed to capture a motor disorder, that indicates PD symptom such as tremor. Initial trials of the developing demonstrated that the monitoring system has the ability to real-time data acquisition and transmission using smartphone sensors and cloud storage. The connection settings developed for the system proved to be efficient when sensor data transmitted from the smartphone to cloud storage. The period of time required to transfer data to the cloud equal to the period of time less than one second.

Distributed adaptive vibration control for solar power satellite during on-orbit assembly

The distributed adaptive vibration control for solar power satellite (SPS) during on-orbit assembly is investigated in this paper. Focusing on the platform configuration SPS, the different control units (CUs) and relationship matrices, that describe the topology of whole SPS structure, are firstly defined, and the dynamic model of the CU is proposed through the relationship between the CU and the whole SPS structure. Using the linear quadratic optimal control technique, the adaptive controller of the CU is designed to suppress vibrations, and a compensatory component is included in the controller to deal with the interactions with the whole structure. The closed-loop distributed control system is then developed in the presence of the impact at the specific assembling location, which needs to adaptively update along with the varying dynamic model of the SPS structure during on-orbit assembly. The asymptotic stability of the closed-loop distributed system is investigated, and two representative numerical cases are finally provided. The results demonstrate that the proposed distributed adaptive controllers can significantly suppress the vibration caused by the impact among SPS modules during on-orbit assembly.