Multipoint Connection Research Articles

Multipoint communication using a fog-robotic coordinated nodal conveying system for wireless networks

Fog computing is a framework that makes use of the features of both cloud and edge devices to provide quality services, support mobility, reduce delay & latency, and to provide other services to the recent technologies. The fog computing is incorporated in wireless networks using coordinated multi-point communication, which helps to in sending raw bits over a physical link that connects network swarm nodes rather than logical data packets. This, inturn improves system performance and service quality. In the physical layer, the multipoint connection between swarm nodes established during communication in cellular systems consistently reveals limitations in signaling cost, energy consumption, delay and latency. These limitations nevertheless define a wireless network that integrates wide-ranging applications, from independent systems to extended reality (XR) to support minimal network infrastructure. In this paper, the proposed Fog-Robotic Coordinated Nodal Conveying System (FCNCS) helps optimize the data transmission and lowers the signaling cost of coordinated multipoint communication in the physical layer of a wireless system. Besides, optimized link utilization helps to lower signaling costs by 14.3% with improved coordinated multi-point communication network performance efficiency by 85.5% in the physical layer of the wireless framework compared to the existing methods.

Numerical investigation of the effects of model and operator uncertainties on component-based transfer path analysis methods with substructuring applied to aircraft-like components

Hydraulic pumps are considered to have a major contribution to the structure borne noise generated inside aircrafts. Methods such as Component-Based Transfer Path Analysis (CB-TPA) are promising tools for aircraft manufacturers to build internal processes for the specification, design and validation of the impact of vibrating systems on new aircrafts. However, the experimental applicability of these methods remains limited due to some experimental difficulties. CB-TPA' formulation is based on dynamical quantities, which require the determination of terms related to rotational degrees of freedom. Virtual Point (VP) or Equivalent Multi-Point Connection (EMPC) methods are commonly employed for this purpose, but both result in more cumbersome experimental set-ups and increased measurement uncertainties. The implementation of these methods is difficult in the case of a flat and thin receiving structure as commonly encountered in aircraft applications, since in-plane translational excitations have to be applied and the access to the vibrating system/structure interface points is limited. In this work, a decoupling procedure is used to overcome these issues. A numerical model is used to investigate the influence of model and operator uncertainties on the CB-TPA' predictions, when the dynamical quantities are provided by VP and EMPC methods including the decoupling procedure.

High-temperature sintering resistance of novel NdYbZr2O7 thermal barrier coating

Ceramic materials of thermal barrier coatings (TBCs) inevitably undergo sintering during long-term service, which can deteriorate the performance at high temperatures. Sintering behavior is commonly a key index for evaluating the application potential of TBCs. Here, we conducted the thermal exposure experiments on the novel NdYbZr2O7 coating at 1300 °C. Results show that multipoint connection is the dominant sintering mechanism. Based on the porosity evolution, the whole sintering process is divided into two stages: 1) stage I characterized by the healing of most equal-width intrasplat cracks and narrow tip of wedge-like intersplat cracks, and 2) stage II characterized by the healing of residual wide part of intersplat cracks. As the thermal exposure duration increases, thermal conductivity of coating at 800 °C increases from ~0.72 W⋅m−1⋅K−1 to ~1.19 W⋅m−1⋅K−1. The linear correlation between the porosity and thermal conductivity indicates that porosity is the critical factor controlling the thermal conductivity of the coating. In comparison with other coatings such as YSZ and SrAl12O19 reported in previous literature, NdYbZr2O7 coating exhibits better thermal insulation and higher sintering resistance. In addition, Young's modulus of coating first rapidly increases and then slowly with time, closely associated with the evolution of porosity.

Secondary-assembled defect-free MOF membrane via triple-needle electrostatic atomization for highly stable and selective organics permeation

Two-dimensional lamellar membranes featuring well-defined nanochannels hold great promise for efficient organics separation. However, the extensively existed non-selective microdefects within laminate architecture would impair separation efficiency and structure stability of membranes. Herein, defect-free metal-organic framework (MOF) lamellar membrane is facilely constructed by triple-needle electrostatic atomization technology. Specifically, one needle atomizes small-sized Cu-TCPP MOF nanosheets (TCPP = meso-tetra(4-carboxyphenyl)porphyrin) to build lamellar skeleton, and the other two needles meantime atomize Cu2+ and TCPP to secondary-assemble crystals among nanosheets. In this manner, these non-selective microdefects are subtly sutured by the regenerated crystals with identical chemical components, resulting in a defect-free MOF lamellar membrane with enhanced structural stability. Importantly, this novel secondary-assembly method highly enhances the separation efficiency and meanwhile keeps high organics permeation for MOF membrane, with rejection of 93.8% for Rose Bengal (1.2 nm) and acetone permeance of 86.9 L m−2 h−1 bar−1. In addition, the multipoint connection between nanosheets and crystals ensures excellent surface shearing and compaction resistance for MOF membrane, permitting high and steady operation performance for over 100 h. This secondary-assembly methodology by one-step process to construct defect-free and steady lamellar membrane provides a new avenue for the development of efficient separation membranes.

Optimal Capacitor Placement for Unbalanced Distribution System using Graph Theory

In this paper, a graph theory-based allocation methodology of capacitor bank is proposed for unbalanced distribution system. A single-stage optimization procedure using electrical centrality measure concept to identify the best suitable locations for the multi-point connection of capacitor is described with its significance in this paper. The electrical centrality measure approach gives ranking of all the buses, single capacitor or multiple capacitors can be placed in unbalanced distribution system (UDS) using these indices to fulfill the reactive power demand and maintain voltage profile of the system. To evaluate the performance of the UDS due to capacitor bank connection two parameters are considered – improvement of overall voltage profile and reduction of active power loss. The contribution of the paper is – first, electrical centrality measure is used for identifying the capacitor bank location in the unbalanced distribution system and second it optimizes the size of the capacitor using two different objectives to improve the system voltage profile and reduce the active power loss. The proposed methodology is tested on a modified 123 bus unbalanced distribution system. The active power loss reduction up to 16.50% and total voltage deviation reduction up to 71.53% were achieved using the proposed method. The obtained results corresponding to the two objectives are also compared.

Research on multi-point connection of under-chassis equipment suspension system in high-speed trains

A power dispersive high-speed electric multiple-unit (EMU) train requires the installation of traction equipment under the carbody. As the speed of high-speed trains increases, the demand for traction power is increasing, and the weight and size of the equipment have increased accordingly. To adapt to the research and development of higher-speed EMU trains, this research proposes the use of a multi-point connection scheme for installing the under-chassis equipment. First, the static deflection and supporting reaction force of each hanging point are obtained based on static analysis, and it is found that increasing the number of connection points is beneficial for reducing the static stiffness requirement of each rubber element. Then, an energy decoupling degree is introduced, and an optimization design method for the hanging point stiffness is proposed based on the energy decoupling degree and optimal vertical suspension frequency. Finally, a rigid-flexible coupling dynamics simulation model is established to analyze the vibration characteristics of the carbody and equipment after decoupling and optimization of the multi-point suspension schemes. The research results show that after the decoupling optimization, the vibration amplitude in the middle of the carbody is effectively reduced, and the ride quality of the carbody is improved. The difference in the number of hanging points has little effect on the vibration performance of the carbody, but increasing the number of hanging points is beneficial for reducing the dynamic supporting reaction forces of the hanging components, thereby reducing the dynamic stress of the rubber elements.

On-demand Photonic Multipoint Connection Technology Supporting High-presence Communications Services

On-demand Photonic Multipoint Connection Technology Supporting High-presence Communications Services

Multipoint connection by long-range density interaction and short-range distance rule

The performance of a system is influenced by the way its elements are connected. Networks of cells with high clustering and short paths communicate more efficiently than random or periodic networks of the same size. While many algorithms exist for generating networks from distributions of points in a plane, most of them are based on the oversimplification that a system’s components form connections in proportion to the inverse of their distance. The Waxman algorithm, which is based on a similar assumption, represents the gold standard for those who want to model biological networks from the spatial layout of cells. This assumption, however, does not allow to reproduce accurately the complexity of physical or biological systems, where elements establish both short and long-range connections, the combination of the two resulting in non-trivial topological features, including small-world characteristics. Here, we present a wiring algorithm that connects elements of a system using the logical connective between two disjoint probabilities, one correlated to the inverse of their distance, as in Waxman, and one associated to the density of points in the neighborhood of the system’s element. The first probability regulates the development of links or edges among adjacent nodes, while the latter governs interactions between cluster centers, where the density of points is often higher. We demonstrate that, by varying the parameters of the model, one can obtain networks with wanted values of small-world-ness, ranging from ∼1 (random graphs) to ∼14 (small world networks).

All-optical encryption in 80-Gbps next-generation passive optical network stage 2

Passive optical network broadcasts extensive data to subscribers. However, they are vulnerable to various security attacks. The main objective of our work is to assess the information security aspects at the physical layer of next-generation passive optical network stage 2 (NG-PON2). Our paper focuses on the security issues faced by NG-PON2, and we propose an encryption method using the all-optical exclusive-OR gate. The proposed simulation architecture of symmetric 80-Gbps NG-PON2 is based on array waveguide grating. Further, we verified the inherent security of the NG-PON2 system through an eavesdropping attempt at an optical network unit (ONU). For this, we used a key exchange mechanism using the Diffie–Hellman algorithm for sharing individual unique keys between every ONU and the optical line terminal. The simulation results show that the presented technique provides secure broadband services in the access network. The transmitted data are encrypted to ensure confidentiality on the multipoint fiber connection. We have evaluated the transmission performance of the proposed set up and achieved acceptable results in terms of Q-factor (7.12 dB) and bit error rate of (5.26 × 10 − 13). The bits in the optical domain, which are sent to the first ONU, are also compared with the received optical bits at the receiving ONU. The correct reception of the bits at the intended ONU and the inability of malicious ONUs to eavesdrop the data of other ONUs validates the scheme.

A new family of generalized parallel manipulators with configurable moving platforms

A Conventional Parallel Manipulator (CPM) usually uses a rigid moving platform as the end-effector to connect serial legs. Since serial legs independently support the platform, kinematic joints are embedded into the rigid moving platform. However, the moving platforms of Generalized Parallel Manipulators (GPMs) are not limited to rigid bodies. The introduction of configurable platforms with integrated end-effectors allows for providing a multipoint connection with the environment. As a result, the functionality of parallel manipulators can be further extended. Resulting from the property of the platform, a significant challenge of connecting moving platforms with serial limbs is posed. This paper puts forward a systematic method for synthesizing parallel manipulators with configurable platforms. To realize the cooperation of the integrated end-effectors, the multi-drive hybrid limbs are designed base on the screw theory. According to the constraint synthesis method, a novel class of parallel manipulators with configurable platforms is constructed. Then the examples with different motion patterns are offered to corroborate the effectiveness of the proposed method. At last, driving schemes and the potential applications of the derived manipulators are discussed.

Introduction of line contact in frequency-based substructuring process using measured rotational degrees of freedom

The theory of frequency-based substructuring enables us to combine the dynamical behavior of multiple subsystems into the common response of the whole system. Subsystem’s properties can be numerically or experimentally obtained in the form of frequency response functions. Response models are then coupled together taking into account a connectivity conditions. However, when one is dealing with a statically indeterminate multi-point connections such as flanges connected over several bolts, it is difficult to properly define a model in the numerical environment. In order to obtain real contact conditions a few methods like virtual point transformation and multi-point connection were proposed in recent years. Since an indirect approach of obtaining rotational motion struggle to accurately define local dynamic characteristics i.e. antiresonances, it also rely on assumption of rigid interface. In this paper we are introducing an alternative approach, where all six degrees of freedom are experimentally obtained with aim to directly address local joint flexibility in the substructuring process. This procedure represent an alternative to the method that removes the effects of a flexible fixture, however here it is done directly by measuring contact dynamic without the need of additional fixture block. Rotational responses are directly obtained using rotational accelerometer that enable us to gather all six degrees of freedom in each experimental point. Consequently, contact can be fully defined with less measurement points where several of them with only translational responses are required in other methods for reconstruction of rotational motion.

Theoretical and experimental evaluation of electromagnetic induction from power line upon multi-points grounded conductors

Electromagnetic induction between power lines and telecommunication cables may cause physical injury of service personnel, and malfunction or quality degradation of telecommunication services. Therefore, the influence of electromagnetic induction on telecommunication cables has been studied since early 1900’s. However, due to a complicated configuration and multi-point connection to the ground, there were few studies on induction phenomenon to a suspension wires that support overhead telecommunication cable. In this paper, we have studied on induction phenomena upon multiple point grounded conductors, theoretically and experimentally. As a result, we confirmed that calculated and measured results are in good agreement with ideal conditions.

A comprehensive sintering mechanism for TBCs‐Part II: Multiscale multipoint interconnection‐enhanced initial kinetics

AbstractDuring thermal exposure, the sintering process of the plasma‐sprayed thermal barrier coatings (PS‐TBCs) presents significant two‐stage kinetics, as reported in the Part I. As a companion study, this part aims to reveal the mechanism responsible for the ultrafast sintering kinetics when initially exposed, since the initial short stage (stage‐I) often finishes most increment of the mechanical and thermal properties. A detailed examination of the pore healing behavior was carried out, based on the experimental result in Part I that the dominant structural change at the stage‐I is the significant healing at intersplat pore tips. Results show that the smooth splat surface, which made up the wedge‐shaped intersplat pores, changed to a rough surface with multiscale convexs after high‐temperature thermal exposure. Moreover, the multiscale roughening is highly sensitive to various orientations of the columnar grains inside the splats. Subsequently, multipoint connection between the counter‐surfaces of the intersplat pores was formed by the bridging of multiscale convexs. This multiscale multipoint connection between pore surfaces significantly accelerated the healing of intersplat pores, which can be dominantly responsible for the ultrafast sintering kinetics at the stage‐I. This comprehensive sintering mechanism could offer some positive suggestions toward prolonging the thermal‐insulating effect of TBCs.

A comprehensive sintering mechanism for TBCs‐Part I: An overall evolution with two‐stage kinetics

AbstractA comprehensive sintering mechanism for lamellar thermal barrier coatings was reported experimentally and theoretically in this study. To begin with, an overall property evolution with two‐stage kinetics was presented during thermal exposure. The increase in mechanical property at initial thermal exposure duration (stage‐I) was much faster with respect to that in the following longer duration (stage‐II). At the stage‐I, the in situ pore healing behavior revealed that the significant faster sintering kinetics was attributed to the rapid healing induced by multipoint connection at the intersplat pore tips, as well as a small quantity of the narrow intrasplat cracks. At the following stage‐II, the residual wide intersplat pore parts and the wide intrasplat cracks decreased the possibility of multiconnection at their counter‐surfaces, resulting in a much lower sintering kinetic. Moreover, a structural model based on the microstructure of plasma sprayed YSZ coatings was developed to correlate the microstructural evolution with mechanical property. Consequently, the model predicted a two‐stage evolutionary trend of mechanical property, which is well consistent with experiments. In brief, by revealing the pore healing behavior, this comprehensive sintering mechanism shed light to the structure tailoring toward the advanced TBCs with both higher thermal‐insulating effect and longer life time.

Simulation of stress in an innovative combination of composite with metal sheet

In this article research of stress impact in multi-point connection glass epoxy composite with a metal sheet with a rivet nuts was presented. Composite materials are increasingly used because of the good mechanical properties and low price. The laminates are composites of a layer structure, characterized by very high strength in the direction of the fibers, their weakness is not good toughness in a direction perpendicular to the layers. Mainly checking of displacements and stresses generated on the sheet as a result of pneumatic actuators load for composite boards was carried out. Glass-epoxy composite consisting of four layers of glass mat with a weight of 1000 g/m2 and an epoxy resin and hardener HG700 LG700 volume ratio of 38/100 was created. Next composite was fixed with steel plate with a rivet nuts and bolts. A model of laminate samples and plate was simulate in Siemens NX 8.5 software. The simulation results will determine stresses and displacements in conjunction newly designed composite sheet. Strength analysis was performed with the use of the module NX Advanced Simulation. FEM is an advanced method for solving systems of differential equations, based on the division of the field into finite elements for which the solution is approximated by specific functions, and performing the actual calculations only for nodes of this division. Due to the complexity of the created object to simplify the elements made to reduce the calculation time. This article presents the study of stresses and displacements in the composite plates joined with sheet metal, in summary of this article, the authors compare the obtainted results with the computer simulation results in the article: " The study of fix composite panel and steel plates on testing stand".

A Comparative Study on Methods of Connecting Large-Scale Offshore Wind Farms into Power Systems

The paper uses PSS/E software to study connecting an offshore wind farm with 864 MW into the 2015 Taiwan power system. Major simulation works include: steady-state power flow, fault current computation, transient stability analysis and the impact analysis on critical fault clearing time. Three connection methods, i.e., single-point, separatepoint and multi-point connection, are proposed, in which the single-point connection is divided into two voltage levels (161kV and 345kV). During the steady-state operation, simulation results indicate that the 345 kV single-point connection method demonstrates the best performance. In addition, the fault current from a wind farm is partially determined by its connection location. In terms of transient stability, when grid faults take place, the 161kV singlepoint connection method appears to report the smallest voltage drop as compared to other connection scenarios. Its amplitude of frequency disturbance, however, is the greatest of all connection scenarios. As for the analysis on critical fault clearing time, simulation results indicate that the critical fault clearing time in all connection cases is approximately two times greater than that required by the Taipower standard. Simulation results in this study can be expected to provide valuable guidelines for connecting offshore wind farms into the power systems in the future.

Fixed and Mobile WiMAX: A Comparison towards the Distance and Height Effects on Performance Degradation

 Abstract—Worldwide Interoperability for Microwave Access or WiMAX is a wireless communication system that can provide long distance wireless broadband access with high data throughput in a point to multipoint connection and line of sight or non-line of sight environment. There are two variants of the WiMAX standard called Fixed and Mobile WiMAX. Fixed WiMAX 802.16 delivers point to multipoint broadband wireless access to our homes and offices. Whereas Mobile WiMAX 802.16e gives fully mobile internet access at higher broadband speeds than other broadband networks like Wi-Fi. The paper objective is to compare the performance of Fixed and Mobile WiMax network within the sub urban area by simulating several scenarios. Ten scenarios were created from previous works, by using an open source simulator called NCTUns 5.0. The simulations were based on the changes of system parameters which are base station's antenna height and distance between Base Station (BS) and Subscriber Station (SS). Both Fixed WiMAX and Mobile WiMAX topology has been tested, and the percentages of performance degradation were analyzed and compared.

Rendezvous Multicast: A Novel Architecture for MPLS QoS Multicast

IP multicast and MPLS (multi-protocol label switching) are proposed to support emerging network applications effectively, extending current IP routing and switching mode in different ways. It is still in progress to combine IP multicast with MPLS properly. In this paper, a novel architecture, called Rendezvous MPLS Multicast, is proposed to support IP multicast in MPLS networks and to have the scalability of multicast routing, to achieve the label space reduction, and to solve some practical problems in implementation. A two-layered structure of control plane without multicast routing protocols is implemented by overlaying novel service control plane over the existing routing control plane to support multicast state aggregate. The interface between the two planes is formulated to support the interaction and cooperation. Moreover, the label distribution process for MPLS P2MP (point to multi-point) connection, with RSVP-TE (resource reservation protocol-traffic engineering) protocol, is extended to support aggregate of multiple label switching paths with traffic engineering and guarantee of quality of service. An algorithm of selecting Rendezvous Routers for Rendezvous MPLS Multicast has been presented. A test-bed with Linux-based implementations of MPLS multicast router and IP multicast service control system has also been constructed. The experimental results show its efficiency in terms of label space reduction and multicast traffic balancing, with the whole system adapting to the dynamic change of group members and network topology.

Practice and Evaluation about Distance Classes using High Quality Video/Audio Stream with Multi Point Connection between Japanese and Korean Middle Schools (<Special Issue>Studies on Practical Use of e-Learning)

Practice and Evaluation about Distance Classes using High Quality Video/Audio Stream with Multi Point Connection between Japanese and Korean Middle Schools (<Special Issue>Studies on Practical Use of e-Learning)

이동 시스템 제어를 위한 블루투스 네트워크

Bluetooth technology is essentially a method for wireless connectivity of a diverse set of devices ranging from PDAs, mobile phone, notebook computers, to another equipments, The bluetooth system both point-to point connection and point-to multipoint connection. In point-to multipoint connection, the channel is shared among several bluetooth devices. Two or more devices sharing the same channel form a piconet. There one master device and up to seven active slave devices in a piconet. The radio operates in the unlicensed 2.45GHz ISM band. This allows users who travel world-wide to use bluetooth equipments anywhere. Since the link is based on frequency-hop spread spectrum, multiple channels can exist at the same time. The bluetooth standard ha s been suggested that bluetooth equipments can be used in the short-range, maximum 100 meters. It has been defined that the time takes to setup and establish a bluetooth connection among devices is 10 seconds. It is a long time and may be a cause to lose a chance of finding other non-fixed devices. We propose a routing protocols for scatternets which can be used to control a mobile units(MUs) in this network. The proposed routing protocol is composed of two kinds of bluetooth information, access point(AP) and MU.