Digital optical networks using photonic integrated circuits (PICs) address the challenges of reconfigurable optical networks

To reduce costs and simplify operations, carriers are deploying flexible optical networks that can be easily reconfigured and managed remotely. This article provides an overview of typical all-optical reconfigurable optical add/drop multiplexer (ROADM) systems and their associated network issues. We describe a novel digital optical network architecture based on digital ROADM systems, which use photonic integrated circuits (PICs) to overcome many of these issues. Digital ROADM systems use monolithic PICs to integrate over 60 discrete optical components, including lasers, modulators and detectors, into a single pair of optical components, allowing cost-effective optical-electrical-optical conversion at every node. This also allows key functions such as service reconfiguration, add/drop and protection to be implemented in the digital domain, and enables de-coupling of service provisioning from optical link engineering, termed bandwidth virtualization. Finally, key deployment, reliability and operational metrics for PIC-based digital ROADM systems are presented.     

Electronic prognostics for switched mode power supplies

Switching power supplies have become ubiquitous in electronic modules and systems. From converting power types, power levels, or driving actuators, these power converters embody varying topologies but usually have high switching rates of up to 500 KHz, power devices such as MOSFETs, microelectronic components and a mix of passive components that store and release energy. They are complex modules that have an unfortunate history of observed high failure rates, yet they may be required to support critical systems.Electronic prognostics/health management, or ePHM, provides the ability to predict the failure of the electronic before it actually occurs. This paper will examine the considerations associated with key system- and device level prognostics that designers need to evaluate when “PHM-enabling” their power system.     

Luminescent Ions in Advanced Composite Materials for Multifunctional Applications

Luminescent ions doped materials have been widely applied in many areas, both scientific research and practical fields. Recently, incorporating luminescent ions and advanced materials into versatile and multifunctional systems seems to be a tendency, motivated by the stimulating desires of fundamental studies and technological applications. This feature article provides a general overview of the myriad of luminescent ions‐based advanced composite materials recently investigated. It is demonstrated that the improved or additional properties may be achieved via implementing a strategy of incorporating luminescent ions (lanthanide, transition and main group metal ions) into various types of materials, such as flexible polymers, two‐dimensional atomically thin layers, porous materials, and so on. We outline the design principles, synthesis and processing of various systems joined by luminescent ions doped phosphors. A number of recent works indicate that those novel composite materials allow one to conceive and develop multifunctional applications in a broad area, including optoelectronics, photonics, clean energy, biomedicine, and new types of sensors. Lastly, some challenging issues are discussed and potential directions are suggested for further developing advanced composite materials incorporated with luminescent ions.     

A New Model for Autonomous, Networked Control Systems

Existing communication utilities, such as the ISO/OSI model and the associated automation pyramid, have limitations regarding the increased complexity of modern automation systems. The introduction of profiles for fieldbus systems, or field-area networks (FANs), was an important innovation. However, in the foreseeable future the number of FAN nodes in building automation systems is expected to increase drastically. And here the authors see an opportunity to revolutionize the operation of intelligent, autonomous systems based on FANs. The paper introduces a system based on bionic principles to process the information obtained from a large number of diverse sensors. By means of multilevel symbolization, the amount of information to be processed is substantially reduced. A symbolic processing model is introduced that enables the processing of real world information, creates a world representation, and evaluates scenarios that occur in this representation. Two applications involving human actions in a building automation environment are briefly discussed. It is argued that the use of internal symbolization leads to greater flexibility in the case of a large number of sensors, providing the ability to adapt to changing sensor inputs in an intelligent way     

Generalized Bayesian hypothesis testing for cell coveragedetermination

Determining the best base station to serve a mobile user is a key process in cellular systems. Optimal selection of a serving base station guarantees high quality calls and a minimum number of handoffs. Traditional algorithms rely on hysteresis levels to determine the serving base station when a handoff is requested. In this work, optimal hysteresis levels are generated using Bayesian hypothesis tests allowing to incorporate in the hysteresis level information such as call processing costs, mobility profiles, cell sizes and traffic unbalance. Hysteresis impact on handoff uncertainty is assessed through an entropic indicator     

Reliability Issues in Photovoltaic Power Processing Systems

Power processing systems will be a key factor of future photovoltaic (PV) applications. They will play a central role in transferring, to the load and/or to the grid, the electric power produced by the high-efficiency PV cells of the next generation. In order to come up the expectations related to the use of solar energy for producing electrical energy, such systems must ensure high efficiency, modularity, and, particularly, high reliability. The goal of this paper is to provide an overview of the open problems related to PV power processing systems and to focus the attention of researchers and industries on present and future challenges in this field.     

Instrumentation Location Diversity Paradigm for Future Astronomy Observations

Capital constrained organizations desiring to conduct astronomy observations face significant challenges due to the high cost of acquiring telescopes and computing facilities. Approaches such as re-using discarded earth stations can reduce telescope acquisition costs. In addition, an increasing population also reduces land suitability and availability for establishing radio quiet zones. These challenges affect the ability of capital constrained astronomy organizations in high population density regions to conduct astronomy observations. This paper proposes the use of drones to address these challenges. Drone based telescopes and computing systems in the airspace are less reliant on land resources. They can be used to conduct astronomy observations in high population regions. The paper presents the architecture of the drone based astronomy system and discusses relations between the drone and terrestrial astronomy systems. The performance benefits of the proposed architecture are investigated by formulating a model and conducing numerical simulation. It can be seen that using the proposed architecture reduces ownership costs by up to 51.2% on average and improves the power efficiency by up to 33% on average. In addition, the use of the proposed drone based telescope architecture enhances the angular resolution by 74.3% on average.

     

RapidIO 并发静态路由枚举技术

新的作战对象和作战环境对现代雷达系统提出了新的挑战,需要具备同时多功能、复杂电磁环境对抗以及宽带成像和识别等能力。雷达系统数字化技术发展需要信号处理架构能够满足海量数据高速实时传输,并且运算节点可任意交换以及可重构能力。传输交换体系是构建大带宽、高密度计算实时处理系统关键技术。文中介绍了动态最短路径枚举路由技术,可实现基于RapidIO 协议处理平台的全交换拓扑结构;提出了可提升传输带宽和平台并行处理能力的并发静态枚举路由技术,可实现处理平台的网状多链路并行全交换拓扑结构。     

Lightweight and scalable secure communication in VANET

To avoid a message to be tempered and forged in vehicular ad hoc network (VANET), the digital signature method is adopted by IEEE1609.2. However, the costs of the method are excessively high for large-scale networks. The paper efficiently copes with the issue with a secure communication framework by introducing some lightweight cryptography primitives. In our framework, point-to-point and broadcast communications for vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) are studied, mainly based on symmetric cryptography. A new issue incurred is symmetric key management. Thus, we develop key distribution and agreement protocols for two-party key and group key under different environments, whether a road side unit (RSU) is deployed or not. The analysis shows that our protocols provide confidentiality, authentication, perfect forward secrecy, forward secrecy and backward secrecy. The proposed group key agreement protocol especially solves the key leak problem caused by members joining or leaving in existing key agreement protocols. Due to aggregated signature and substitution of XOR for point addition, the average computation and communication costs do not significantly increase with the increase in the number of vehicles; hence, our framework provides good scalability.     

Design and Implementation of High-Performance RNS Wavelet Processors Using Custom IC Technologies

The design of high performance, high precision, real-time digital signal processing (DSP) systems, such as those associated with wavelet signal processing, is a challenging problem. This paper reports on the innovative use of the residue number system (RNS) for implementing high-end wavelet filter banks. The disclosed system uses an enhanced index-transformation defined over Galois fields to efficiently support different wavelet filter instantiations without adding any extra cost or additional look-up tables (LUT). A selection of a small wordwidth modulus set are the keys for attaining low-complexity and high-throughput. An exhaustive comparison against existing two's complement (2C) designs for different custom IC technologies was carried out. Results reveal a performance improvement of up to 100% for high-precision RNS-based systems. These structures demonstrated to be well suited for field programmable logic (FPL) assimilation as well as for CBIC (cell-based integrated circuit) technologies.     

Fabrication of Silk Microneedles for Controlled‐Release Drug Delivery

Microneedles are emerging as a minimally invasive drug delivery alternative to hypodermic needles. Current material systems utilized in microneedles impose constraints hindering the further development of this technology. In particular, it is difficult to preserve sensitive biochemical compounds (such as pharmaceuticals) during processing in a single microneedle system and subsequently achieve their controlled release. A possible solution involves fabricating microneedles systems from the biomaterial silk fibroin. Silk fibroin combines excellent mechanical properties, biocompatibility, biodegradability, benign processing conditions, and the ability to preserve and maintain the activity of biological compounds entrained in its material matrix. The degradation rate of silk fibroin and the diffusion rate of the entrained molecules can be controlled simply by adjusting post‐processing conditions. This combination of properties makes silk an ideal choice to improve on existing issues associated with other microneedle‐based drug delivery system. In this study, a fabrication method to produce silk biopolymer microstructures with the high aspect ratios and mechanical properties required to manufacture microneedle systems is reported. Room temperature and aqueous‐based micromolding allows for the bulk loading of these microneedles with labile drugs. The drug release rate is decreased 5.6‐fold by adjusting the post‐processing conditions of the microneedles, mainly by controlling the silk protein secondary structure. The release kinetics are quantified in an in vitro collagen hydrogel model, which allows tracking of the model drug. Antibiotic loaded silk microneedles are manufactured and used to demonstrate a 10‐fold reduction of bacterial density after their application. The processing strategies developed in this study can be expanded to other silk‐based structural formats for drug delivery and biologicals storage applications.     

Shedding light on the future of SP for optical recording

Optical recording has lagged behind magnetic recording in two key areas: writable/erasable/rewritable media and density gains from advanced signal processing. While there are some writable optical-disk products available, their writing capability pales in comparison to magnetic recording. A great deal of research and development in writable/erasable/rewritable optical media continues and we address this in the article. Of particular interest is the use of near-field optical approaches to dramatically increase the storage density in both magnetic and optical recording. To a great extent, this article is about the future of signal processing for optical recording, since advanced signal processing has not been applied to any great extent in optical recording. The intention is twofold: (1) to provide a summary of current and existing optical recording technologies, and (2) to encourage and motivate work in advanced signal processing for these and other optical systems. We begin by summarizing the optical recording and readback processes and then describe writable optical channels and the gains associated with using partial-response coding techniques. We then describe nonbinary recording and the potential gains due to signal processing. The digital versatile disc (DVD), multilayer recording, and holographic recording are also discussed     

Review of saw devices and their signal processing applications in space communications

An increasing number of advanced signal processing techniques are being investigated in satellite communications systems as the ground and space segments require more and more sophisticated, light-weight, low-power-consumption and cost-effective equipment. RF signal processing techniques based on surface acoustic wave (SAW) devices can be suitably exploited in these systems, constituting a valid alternative to digital baseband processing. This paper aims at presenting the most recent applications of SAW devices to RF signal processing in satellite communication systems. They span the frequency range from about 10 MHz to 10 GHz. Interaction of SAWs with laser beams is also illustrated.     

A comparative study of pattern recognition techniques for qualityevaluation of telecommunications software

The extreme risks of software faults in the telecommunications environment justify the costs of data collection and modeling of software quality. Software quality models based on data drawn from past projects can identify key risk or problem areas in current similar development efforts. Once these problem areas are identified, the project management team can take actions to reduce the risks. Studies of several telecommunications systems have found that only 4-6% of the system modules were complex [LeGall et al. 1990]. Since complex modules are likely to contain a large proportion of a system's faults, the approach of focusing resources on high-risk modules seems especially relevant to telecommunications software development efforts. A number of researchers have recognized this, and have applied modeling techniques to isolate fault-prone or high-risk program modules. A classification model based upon discriminant analytic techniques has shown promise in performing this task. The authors introduce a neural network classification model for identifying high-risk program modules, and compare the quality of this model with that of a discriminant classification model fitted with the same data. They find that the neural network techniques provide a better management tool in software engineering environments. These techniques are simpler, produce more accurate models, and are easier to use     

Hardware-accelerated design space exploration framework for communication systems

The efficient hardware implementation of signal processing algorithms requires a rigid characterization of the interdependencies between system parameters and hardware costs. Pure software simulation of bit-true implementations of algorithms with high computational complexity is prohibitive because of the excessive runtime. Therefore, we present a field-programmable gate array (FPGA) based hybrid hardware-in-the-loop design space exploration (DSE) framework combining high-level tools (e.g. MATLAB, C++) with a System-on-Chip (SoC) template mapped on FPGA-based emulation systems. This combination significantly accelerates the design process and characterization of highly optimized hardware modules. Furthermore, the approach helps to quantify the interdependencies between system parameters and hardware costs. The achievable emulation speedup using bit-true hardware modules is a key enabling the optimization of complex signal processing systems using Monte Carlo approaches which are infeasible for pure software simulation due to the large required stimuli sets. The framework supports a divide-and-conquer approach through a flexible partitioning of complex algorithms across the system resources on different layers of abstraction. This facilitates to efficiently split the design process among different teams. The presented framework comprises a generic state of the art SoC infrastructure template, a transparent communication layer including MATLAB and hardware interfaces, module wrappers and DSE facilities. The hardware template is synthesizable for a variety of FPGA-based platforms. Implementation and DSE results for two case studies from the different application fields of synthetic aperture radar image processing and interference alignment in communication systems are presented.     

Dielectric Modulated Cellulose Paper/PDMS‐Based Triboelectric Nanogenerators for Wireless Transmission and Electropolymerization Applications

Achieving high output performance is the key in the development of triboelectric nanogenerators (TENGs) for future versatile applications. In this study, a novel TENG assembled with porous cellulose paper and polydimethylsiloxane is demonstrated. Through dielectric modulation of the friction materials by the nanoparticles (i.e., BaTiO₃, Ag), the triboelectric outputs increase significantly with the permittivity increase, which is attributed to the enhancement of the charge trapping capability and the surface charge density of the friction materials. The dielectric modulated TENG demonstrates a high output voltage of 88 V and a current of 8.3 µA, corresponding to an output power of 141 µW. Acting as a sensor unit, the TENG can successfully operate in a wireless transmission system, which can remotely monitor the machine operation and deliver the messages associated with finger movements. Moreover, the TENG can also perform as an efficient power source in an electropolymerization system for electropolymerizing polyaniline on a carbon nanotube electrode, holding a great potential to synthesize a high capacitance electrode for supercapacitors. This work provides a simple and efficient way to construct high performance TENGs and promotes their practical applications in the fields of wireless transmission and electropolymerization systems.     

Guest Editorial: Special Issue on Signal Processing Systems: Part I

The design of high performance, high precision, real-time digital signal processing (DSP) systems, such as those associated with wavelet signal processing, is a challenging problem. This paper reports on the innovative use of the residue number system (RNS) for implementing high-end wavelet filter banks. The disclosed system uses an enhanced index-transformation defined over Galois fields to efficiently support different wavelet filter instantiations without adding any extra cost or additional look-up tables (LUT). A selection of a small wordwidth modulus set are the keys for attaining low-complexity and high-throughput. An exhaustive comparison against existing two's complement (2C) designs for different custom IC technologies was carried out. Results reveal a performance improvement of up to 100% for high-precision RNS-based systems. These structures demonstrated to be well suited for field programmable logic (FPL) assimilation as well as for CBIC (cell-based integrated circuit) technologies.

     

A 10 Gb/s hybrid-integrated receiver array module using a planarlightwave circuit (PLC) platform including a novel assembly regionstructure

A planar lightwave circuit (PLC) platform for optoelectronic hybrid integration shows potential for achieving 10 Gb/s operation. It uses AuSn bump-type bonding pads on a silica layer to decrease parasitic capacitance, which limited the CR time constant in the optical chip assembly region, and two-layer electrical wiring to reduce parasitic inductance, which caused resonance in the electrical circuit region. An arrayed receiver module fabricated by integrating a two-channel monolithic opto-electronic integrated circuit (OEIC) chip on the PLC platform demonstrated a 3 dB-bandwidth of 8 GHz in both channels, which is equal to the bandwidth of the OEIC chip. This shows the feasibility of using this PLC platform for multichannel 10 Gb/s operation. Furthermore, this PLC platform can combine the versatile optical circuit functions of a PLC, such as an arrayed-waveguide grating wavelength multiplexer, with the high-speed signal processing function of mature electronic IC circuits. Consequently, this platform is a key device that will lead to high-capacity optical signal processing systems using optical wavelength/frequency routing     

Space-time adaptive processing: a knowledge-based perspective for airborne radar

This article provides a brief review of radar space-time adaptive processing (STAP) from its inception to state-of-the art developments. The topic is treated from both intuitive and theoretical aspects. A key requirement of STAP is knowledge of the spectral characteristics underlying the interference scenario of interest. Additional issues of importance in STAP include the computational cost of the adaptive algorithm as well as the ability to maintain a constant false alarm rate (CFAR) over widely varying interference statistics. This article addresses these topics, developing the need for a knowledge-based (KB) perspective. The focus here is on signal processing for radar systems using multiple antenna elements that coherently process multiple pulses. An adaptive array of spatially distributed sensors, which processes multiple temporal snapshots, overcomes the directivity and resolution limitations of a single sensor.     

求解关联维数的快速算法研究

针对关联维数计算速度慢、耗时多和运算效率低的缺陷,本文从算法和结构两个方面研究了关联维数的快速求解方法,提出了区间阈值累加法和区间维值累加法.这两种算法通过对 · 表格的批处理填写以达到减少重复运算和提高计算效率的要求.文中详细地介绍了算法步骤,分析了算法的运算量,通过与标准算法和一般改进算法的比对,显示出本文提出算法的优越性.