Real-time Interference Research Articles

Power and Channel Optimization for WiFi Networks Based on REM Data

The very high commercial exploitation of the WiFi based technologies in recent years and the absence of solutions for optimal WiFi orchestration, usually leads to suboptimal spectrum usage and user performances. The combination of WiFi based radio resource management (RRM) and the radio environmental maps (REMs) can provide an efficient solution for a Smart-WiFi technology, which improves the underlying spectrum usage as well as network performance. The REM facilitates efficient utilization of the radio environmental data, like device location, estimated channel models, real-time interference levels between the networks, WiFi channels occupancies etc. This information can be utilized for an intelligent and optimal RRM decision making in WiFi related scenarios. This paper proposes a novel REM based RRM approach for management and optimization of commercial WiFi devices that utilizes the available underlying radio environmental information. The paper demonstrates the proposed approach on a commercially available platform, conducting on-the-fly radio environmental data acquisition and optimized WiFi RRM allocation. The simulation analysis results also show that the proposed Smart-WiFi leverage noticeable performance gains for large scale scenarios, compared to conventional WiFi networks.

Real-Time Interference Detection in Tracking Loop of GPS Receiver

Real-Time Interference Detection in Tracking Loop of GPS Receiver

Energy-efficient cluster division for multi-cell joint transmission technology

Coordinated Multi-Point (CoMP) is an effective way to improve user performance in next-generation wireless cellular networks, such as 3GPP LTE-Advanced(LTE-A). The base station cooperation can reduce interference, and increase the signal to interference and noise ratio (SINR) of cell-edge users and improve the system capacity. However, the base station cooperation also adds additional power consumption for signal processing and sharing information through back-haul links between cooperative base stations. As such, CoMP may potentially consume more energy. This paper studies such energy consumption issue in CoMP, presents a semi-dynamic CoMP cluster division algorithm based on energy efficiency (SCCD-EE) that can effectively adapt to users' real-time interference, and employs the idea of Maximal Independent Set (MIS) to solve the problem of cluster overlapping. To verify the feasibility of the proposed algorithm, this paper performs comprehensive evaluations in terms of energy efficiency and system capacity. The simulation results show that the proposed semi-dynamic cluster division algorithm can not only improve the system capacity and the quality of service (QoS) of cell-edge users, but also achieve higher network energy efficiency compared with static cluster methods and Non-CoMP approaches. Copyright © 2016 John Wiley & Sons, Ltd.

A Real-Time Interference Monitoring Technique for GNSS Based on a Twin Support Vector Machine Method.

Interferences can severely degrade the performance of Global Navigation Satellite System (GNSS) receivers. As the first step of GNSS any anti-interference measures, interference monitoring for GNSS is extremely essential and necessary. Since interference monitoring can be considered as a classification problem, a real-time interference monitoring technique based on Twin Support Vector Machine (TWSVM) is proposed in this paper. A TWSVM model is established, and TWSVM is solved by the Least Squares Twin Support Vector Machine (LSTWSVM) algorithm. The interference monitoring indicators are analyzed to extract features from the interfered GNSS signals. The experimental results show that the chosen observations can be used as the interference monitoring indicators. The interference monitoring performance of the proposed method is verified by using GPS L1 C/A code signal and being compared with that of standard SVM. The experimental results indicate that the TWSVM-based interference monitoring is much faster than the conventional SVM. Furthermore, the training time of TWSVM is on millisecond (ms) level and the monitoring time is on microsecond (μs) level, which make the proposed approach usable in practical interference monitoring applications.

Echo Interference Suppression Approach for Doppler Through-Wall Radar

Because of the particularity of through-wall radar (TWR) applications, TWR often operates in a complicated environment, which can lead to severe interferences in the received echo and thus hamper the accurate target detection. To solve the issue, in this paper, an echo interference suppression approach, which combines hardware and algorithm process, is proposed for Doppler TWR. Compared with the traditional methods, which mainly based on the fixed filter parameters, the proposed approach takes advantage of feedback structure and microcontroller to intelligently adjust the filter parameters according to the real-time interference variation and thus achieves not only more effective, but also more stable interference suppression performance even in a dynamic environment. Series of experimental measurements are presented to illustrate the performance of the proposed techniques.

Research of Virtual Assembly Simulation System

Virtual assembly is one of the main contents of the virtual manufacturing; assembly process simulation is an important part to product virtual assembly. The establishment and optimization technology of three-dimensional assembly simulation scene have been studied to develop a virtual machine assembly simulation system, which achieve a virtual simulation of assembly and disassembly of the machine and the integration and improvement of existing collision detection library, design and implement a graphical simulation system collision detection module, which can real-time interference checking to machine parts motion. The system has good human-computer interaction and visual interface, versatility, can be applied to any organization's assembly simulation, and through examples of the validity of the system.

A monitoring system for real-time interference control on large construction sites

Abstract This paper surveys the feasibility of an infrastructureless real-time monitoring system to provide prompt support for inspectors in charge of health and safety management on construction sites. The system was tested in the specific application of monitoring interference between teams working on large construction sites. The system accounts for a wireless and untethered tracking technology and a local server running a software tool for handling collected data, real-time site state visualization and remote interaction with safety inspectors. The low-level tracking technology is a ZigBee-based easily deployable and reconfigurable technology. In this paper the system is found to be able to cover large fields while keeping its non-invasive features, thanks to the implementation of a novel low-power approach. This paper shows the degree of support inspectors can get from the system: it is able to alert in the occurrence of interference and to log any unexpected behavior.

Design Support System with Haptic Feedback and Real-Time Interference Function

When we design and construct a large-scale device, it is very important to confirm the interference among its parts. We might need to confirm not only the interference among the parts that are designed at the start but also the interference with some parts that are added after construction. However, sometimes even on using 3D CAD, we cannot detect the interference or the collision among parts, particularly when these parts form a complex 3D shape. On the other hand, virtual reality devices have been used in various fields such as design support systems; however, real-time collision detection among complex parts has been difficult to achieve. We constructed a system that can detect collision and interference in real time in a virtual reality system. This engine can detect interference between polygons. This enables to calculate more accurately than voxel-based detection engine. Moreover, we propose a dynamic interference vector for removing interference. This vector is defined as a local minimum vector which removes the interference from the same edge where the contact starts. This method enables to prevent an object moves discontinuously, when the interference is removed. Finally, we introduced an example of using this system for assembling parts.

Dynamic Channel Assignment for Large-Scale Cellular Networks Using Noisy Chaotic Neural Network

This paper presents a novel dynamic channel assignment (DCA) technique for large-scale cellular networks (LCNs) using noisy chaotic neural network. In this technique, an LCN is first decomposed into many subnets, which are designated as decomposed cellular subnets (DCSs). The DCA process is independently performed in every subnet to alleviate the signaling overheads and to apportion the DCA computational load among the subnets. Then a novel energy function is formulated to avoid causing mutual interference among neighboring subnets based on the real-time interference channel table. In each subnet, the proposed energy function also satisfies three interference constraints among cells and the number of required channels of each cell, and simultaneously minimizes the total number of assigned channels to improve spectrum utilization. A typical 441-cell LCN with 70 available channels, which can be decomposed into nine 49-cell DCSs, is examined to demonstrate the validity of the proposed technique by blocking probability, including uniform and hot spot traffic patterns.

XML을 이용한 이기종 CAD 조립체 DMU시스템의 설계

As many engineers and technicians are involved in the design process of large scale and/or complex products, there are a lot of miss matches and interferences due to designers’ faults and several kinds of CAD systems. Recently, CAD systems are applied to verify and check the assembly process. Digital Mock-Up(DMU) system, a tool to build a virtual mock-up in the design stage, has been used to prevent the interferences and miss matches during precision design processes. Using the virtual assembly tool, engineers are able to design precision and interference free parts without physical mock-ups. Instead of a single CAD source, several CAD systems are used to design a complex product. Several organizations are involved in the distributed design environment for heterogeneous multi-CAD assembly. XML and the lightweight CAD file are proposed for the multi-CAD assembly. XML data contains hierarchy of the heterogenenous multi-CAD assembly. STEP PDM schema and STEP ISO 10303-28 formations are applied to construct the XML data. The lightweight CAD file produced from various CAD files through ACIS kernel and InterOp not only contains mesh, B-Rep and topological data, but also is used to visualize CAD data and to verify dimensions. Developed system is executed on the desktop computers. It does not require commercial CAD systems to visualize 3D assembly data. Real-time interference and fitness checks, dimensional verification, and design and assembly verification are performed on the developed system. Assembly of heterogeneous models for a car is conducted to verify the effectiveness of the developed DMU system on the Internet.

Optimizing algorithm of interference checking and it’s implement in vehicle electric-brake virtual assembly system

Interference detection is the key technology of design system based on virtual reality, however, with low efficiency and long time-consuming, traditional geometry intersection method is far from the requirement of real-time precise interference detection of complex objects. With the comparison of sphere-tree, axis-aligned bounding box (AABB) and oriented bounding box(OBB) optimizing algorithms, the theoretical basis and flow chart of swift interference detection based on AABB decomposition is presented. Hierarchical bounding box is constructed to approach geometry solid gradually, the components which are impossible to cause interference are removed, so the operand of interference detection is decreased greatly and the efficiency of algorithm is improved. At last, the optimizing algorithm of the interference checking is applied in virtual assembly system electric-brake virtual assembly system, which is developed in Unigraphics(UG) by comparing the operating time with or without the above algorithm. The comparison experiment results show that the AABB optimizing algorithm of the interference checking can shorten the operating time for complicated objects and show very extensive applied prospects.

Role of vinculin in regulating focal adhesion turnover

Although vinculin (−/−) mouse embryo fibroblasts assemble focal adhesions (FAs), they spread more slowly, less extensively, and close a wound more rapidly than vinculin (+/+) cells. To investigate the structure and dynamics of FAs in these cells, we used real-time interference reflection microscopy (IRM) thus avoiding the need to express exogenous GFP-tagged FA proteins which may be misregulated. This showed that the FAs were smaller, less abundant and turned over more rapidly in vinculin null compared to wild-type cells. Expression of vinculin rescued the spreading defect and resulted in larger and more stable FAs. Phosphatidylinositol 4,5-bisphosphate (PIP2) is thought to play a role in vinculin activation by relieving an intramolecular association between the vinculin head (Vh) and tail (Vt) that masks the ligand binding sites in Vh and Vt. To investigate the role of the vinculin/PIP2 interaction in FA dynamics, we used a vinculin mutant lacking the C-terminal arm (residues 1053–1066) and referred to as the ΔC mutation. This mutation reduced PIP2 binding to a VtΔC polypeptide by >90% compared to wild type without affecting binding to Vh or F-actin. Interestingly, cells expressing the vinculinΔC mutant assembled remarkably stable FAs. The results suggest that vinculin inhibits cell migration by stabilising FAs, and that binding of inositol phospholipids to Vt plays an important role in FA turnover.

Real-time interference analysis between a tool and an environment

In applications such as haptic rendering, NC Verification and CAM, it is often necessary to rapidly detect and correct collision between a known tool, such as a cutting tool, and an arbitrary environment, such as the workpiece to be machined. In these situations, the tool can be manually pre-defined, but the workpiece needs a general representation; and careful fulfillment of these requirements enables extremely rapid performance. We describe an algorithm and representations for rapidly detecting and correcting collision between a manually pre-defined tool and an arbitrary workpiece. For the tool, we prescribe a form of CSG consisting of implicit equations separated by binary space partitions. This representation can be enhanced to also yield depth information and exit vector information for many useful solids. The user must hand-construct the tool using this representation. For the environment, we use a cloud of over 10,000 points. This is a general representation. The collision between tens of thousands of points and the implicit representation can be accelerated with a bounding box hierarchy. We show that we can compute collision and correction information at the rate of 1000 times a second, making it possible to perform force control for haptics using the collision detection algorithm in the real-time loop.

A novel method for periodic interference suppression on local telephone loops

An efficient method for real-time periodic interference suppression on telephone lines is proposed. The periodicity of the interference Is exploited by an adaptive phase-locked buffer (APLB), which is used to create the antiphase noise replica. Computer simulations are used to compare the APLB approach with the traditional least mean squares (LMS) algorithm in an adaptive noise cancellation configuration. The new technique outperforms the LMS noise canceller and proves to be a very efficient solution to the power line interference problem.

Developments in ECG acquisition, preprocessing, parameter measurement, and recording.

The subjects considered in this article follow the logical procedures of acquisition, preprocessing, wave detection, parameter measurement, and recording of the ECG. The authors present an economic procedure for simultaneous multichannel signal acquisition, digital real-time interference elimination and drift suppression, a real-time software QRS detector, and algorithms for wave onset and termination determination. The authors also discuss fast algorithms for lengthwise and crosswise lead presentation that supports the use microdot thermal printers for signal recordings.

Quasi-Heterodyne Hologram Interferometry

Wider use of hologram interferometry for quantitative measure-ments has been delayed by the fact that interpolation between the fringe maxima and minima to obtain the optical path difference at a particular point in the field is laborious and inaccurate. A solution to this problem is quasi-hetero-dyne interferometry, which permits rapid and accurate measurements simultaneously at a number of points distributed over the interference pattern. In this technique a television camera is used in conjunction with digital electronics to measure and store the irradiance values at points on a rectangular sampling grid covering the real-time interference fringes. The phase difference between the interfering wavefronts at each point is then calculated from the irradiance values obtained from successive scans of the camera made while the phase of one of the wavefronts is shifted either continuously or in steps. A practical system is described with which values of the optical path difference for 10,000 data points can be obtained with an accuracy of ± A/200 in less than 10 s. The application of quasi-heterodyne hologram interferometry to the measurement of vector displacements and to holographic contouring is discussed.

Hybrid Holographic Interferometer For Measuring Three-Dimensional Deformations

A method for automatically measuring the three-dimensional (3-D) deformations of a diffuse surface is studied, using a real-time holographic interferometer and a television-computer system. The object surface is illuminated from three different directions. The scattered waves are recorded on a thermoplastic hologram. Real-time holographic interference patterns are observed through the hologram in a fixed direction by sequentially applying the three illuminating beams. The three fringe patterns are put into the computer using a television (TV) camera. The relative fringe order numbers are determined over the whole surface. Calculations for obtaining 3-D deformation distributions are performed, and the results are displayed on a cathode-ray tube (CRT) monitor.

Hologram interferometry without a reference beam

Real-time interference fringes have been observed with a diffusely reflecting object in a holographic setup even when the photographic plate is exposed and viewed with the reference beam blanked off. Linear theory can account for these fringes if the major part of the object remains unchanged.

Holographic Interferometer for Isopachic Stress Analysis

Application of holography to photoelasticity is briefly discussed, with emphasis on its potential in isopachic stress analysis. A complete holographic interferometer is described. The method of wavefront reconstruction simplifies the optical requirements in conventional two-beam interferometry. By employing a photochromic recording medium, the technique of real-time interference becomes a practical and convenient process. Examples of isopachic fringe patterns obtained by this interferometer are shown.