Based on the popular orthogonal frequency division multiplexing (OFDM), frequency division multiple access (OFDMA) has emerged as a primary multi-user multiple access scheme in broadband wireless communication systems. In this paper, recent patents on resource allocation techniques in OFDMA-based wireless systems are overviewed. Specifically, we use single cell single input single output (SISO) as the base model and discuss inventions on OFDMA resource allocation in single cell, multi-cell, multiple input multiple output (MIMO), relay and cognitive radio scenarios. As the new multiple access scheme, OFDMA has many advantages over its predecessor CDMA. These patents demonstrate how to exploit the full potential of OFDMA by efficient subcarrier and power allocation in practical wireless communication systems. Finally, this paper forecasts that resource allocation for cooperative systems, hybrid systems, and cognitive Ad Hoc networks will be future research directions. This overview paper aims to provide valuable insight to OFDMA fundamentals for both system engineers and research scholars.
Elastography or elasticity imaging can be defined as the science and methodology of estimating the mechanical properties of a medium (including soft tissue). Elastography methods generally use an external source of force to produce a static or dynamic stress distribution on the probed medium. The applied stress causes a displacement distribution within the medium, which can be measured or imaged by ultrasound, magnetic resonance, or optical methods. In this paper, the relation of elastography to tissue pathology will be described and an overview of a number of recent patents will be provided. The most representative patents on both static and dynamic elastography methods will be presented, and emphasis will be given on the dynamic-based methods and devices that rely on the acoustic radiation force of ultrasound. A short reference will be also provided to patents on magnetic resonance elastography.
The article presented some promising patents and other correlated literature on wavelet functions for rejecting spurious values (gross errors) in a continuous digital sequence of measured values. Moreover, the paper concentrates its attention on an innovative invention which addresses Gross Error Detection using uni-variate signal-based approaches. The developed algorithm is totally general and it is present in some industrial software platforms to detect sensor outliers. Furthermore, it is currently integrated in the inferential modelling platform of the unit responsible for Advanced Control and Simulation Solutions within ABBs (Asea Brown Boveri) industry division. Experimental results using sensor measurements of temperature, pressure and Enthalpy in a Distillation Column are presented in the paper. One of the goals of this paper is to show the possibility to include the wavelet algorithms also for data reconciliations and authentications in modern communication systems such as wireless communication ones. Wavelet packets seem particularly suitable in such kind of applications because they could also be utilized in the compression data system. Therefore, using wavelet packets a more compact and integrated structure of the whole data transmission and data reconciliation system seems to be possible.
Patents relevant to cross-point memory array structure are reviewed. These patents are selected from the categories of cross-point, crossbar, memory array and emerging memory. These patents address the questions of how to build a cross-point memory, including the array structure and read/write circuitries. The list in this patents review is by no means complete and extensive. The purpose is to inspire interests in this relatively new field.
As the trend toward modernization of todays electric power systems deepens, some fundamental problems with electric power systems remain unchanged - system reliability, optimized unit commitment, optimal generation allocation, load forecast, optimal unit control. This paper presents an overview of a series of innovations that have been implemented for better electric power transmission and distribution systems over the past decade, when deregulation has become widely accepted and energy market system designs become more standardized. Several key aspects are reviewed: Power system operation, power system control, and power system markets. Developments, as revealed especially in recent patents, in several important functional areas are emphatically discussed: voltage stability, unit commitment, load forecast, market dispatch. A unified framework is presented in which all these discussions are conducted, and formulated in a unified perspective, where prediction, optimization and control are integrated and work together to attempt to achieve the best overall system control performance, system economics, and yet maintain system stability and required reliability.
This paper reviews some of the most relevant recent patents on waveguide orthomode transducers whose electrical function is to combine or separate two orthogonal polarisations. Different technical solutions are presented with special focus on compactness and/or improved performances. Increased power handling, reduced higher order modes generation, wide frequency band operation, etc. are some of the typical improvements targeted by the presented designs. Most of the solutions can be adapted from dual linear to dual circular polarisation operation with limited design modifications. Some of the discussed solutions can also be adapted into orthomode junctions when multiple frequency band operation is required.
This paper presents an approach to obtain the optimal power flow solution subjected to various system constraints in a power system using an efficient particle swarm optimization (PSO) technique. In a power system, the continuous control variables are the active power output of the generators and voltage magnitudes of the generator buses, while the discrete variables are the transformer tap settings and switchable shunt devices. Generally, the parameter selection in the PSO equations is conceptualized with the local best (pbest) and global best (gbest) of the swarm, which enables a quick decision in directing the search towards the optimal solution. The impact of the inertia weight plays a significant role in the performance of the algorithm. In this paper the PSO algorithm with global-local best inertia weight (GLBestIW) is considered for the optimal power flow problem. The inertia weight in this method is described as a function of pbest and gbest, which allows the PSO to converge faster with better accuracy. The proposed technique is applied to a standard IEEE 30 bus test system, to obtain the optimal power flow solution by choosing the objective function as minimization of the fuel cost. Comparison of the proposed technique with other optimization techniques used for optimal power flow solution shows the superiority of the proposed approach and confirms its potential for solving optimal power flow problems efficiently. The article presents some promising patents on optimal power flow solution.
This article presents a review of power LED lamp drivers. The power source can be either a DC or an AC main. This review concentrates on the power converter topologies used as drivers for power LED lamps with an AC main. A wide variety of applications is possible including street lighting, exhibition displays, backlight, vibrant disco places, fresh fruits/vegetables refrigeration, etc. The review covers insolated/non-isolated converters, resonant converters, and so on. Future technological developments are also discussed. The article presents some promising patents on topologies of LED lamp drivers.