Flexible and Stretchable Antennas for Biointegrated Electronics

Combined advances in material science, mechanical engineering, and electrical engineering form the foundations of thin, soft electronic/optoelectronic platforms that have unique capabilities in wireless monitoring and control of various biological processes in cells, tissues, and organs. Miniaturized, stretchable antennas represent an essential link between such devices and external systems for control, power delivery, data processing, and/or communication. Applications typically involve a demanding set of considerations in performance, size, and stretchability. Some of the most effective strategies rely on unusual materials such as liquid metals, nanowires, and woven textiles or on optimally configured 2D/3D structures such as serpentines and helical coils of conventional materials. In the best cases, the performance metrics of small, stretchable, radio frequency (RF) antennas realized using these strategies compare favorably to those of traditional devices. Examples range from dipole, monopole, and patch antennas for far-field RF operation, to magnetic loop antennas for near-field communication (NFC), where the key parameters include operating frequency, Q factor, radiation pattern, and reflection coefficient S₁₁ across a range of mechanical deformations and cyclic loads. Despite significant progress over the last several years, many challenges and associated research opportunities remain in the development of high-efficiency antennas for biointegrated electronic/optoelectronic systems.     

A microwave chaos generator with a flat envelope of the power spectrum in the range of 3–8 GHz

A promising type of ultrawideband (UWB) signals for communications and radar techniques operating in an unlicensed frequency range of 3.1–10.6 GHz, which has been actively developed in recent years, is offered by chaotic oscillations. We have designed and studied a chaotic oscillator with a uniform distribution of spectral power density in the range of 3–8 GHz. The possibility of using these oscillators in multiband UWB communication systems and noise generators for radio-engineering measurements is discussed.     

Structural health monitoring of civil infrastructure

Structural health monitoring (SHM) is a term increasingly used in the last decade to describe a range of systems implemented on full-scale civil infrastructures and whose purposes are to assist and inform operators about continued 'fitness for purpose' of structures under gradual or sudden changes to their state, to learn about either or both of the load and response mechanisms. Arguably, various forms of SHM have been employed in civil infrastructure for at least half a century, but it is only in the last decade or two that computer-based systems are being designed for the purpose of assisting owners/operators of ageing infrastructure with timely information for their continued safe and economic operation. This paper describes the motivations for and recent history of SHM applications to various forms of civil infrastructure and provides case studies on specific types of structure. It ends with a discussion of the present state-of-the-art and future developments in terms of instrumentation, data acquisition, communication systems and data mining and presentation procedures for diagnosis of infrastructural 'health'.     

Rule of thumb heuristics for configuring storage racks in automated storage and retrieval systems design

A well-known rule of thumb for evaluating storage rack configurations in automated storage and retrieval (ASR) systems is modified to avoid the need for two key assumptions. These are the proportion of single and dual command order picking cycles used in operating a system and the total storage capacity requirements when randomized versus dedicated storage is used. Procedures for generating ASR system cost estimates are also directly coupled with models for estimating the utilization of storage and retrieval machines. Additional performance criteria for evaluation of alternative rack configurations are proposed. The modified rules of thumb are also designed for implementation on PC-level hardware, but with adequate computational efficiency for analysing a broad range of rack design alternatives in large-scale applications. They are demonstrated using a realistic sample problem.     

智能房间空调器通讯模组的设计与试验研究

设计一种适用于智能房间空调器的无线通讯模组。以STC系列单片机为模组的控制核心,可以处理对空调器的短信查询指令、短信控制指令和遥控控制指令,并能搜集空调器的运行状态信息,及时传输;用GSM模块完成模组的短信收发功能,通过RS485控制电路进行控制指令和数据的传送。通过移动控制设备对模组进行恶劣工况试验、极端电压试验、故障报警试验和远程操控试验,结果表明,模组达到日常使用要求,且安全、稳定、可靠,可以在空调器系统上广泛应用。     

Space-based parallel program design process with high-level communication channels

Abstract

In this research, we reduce design complexity of parallel programs by performing the design task at the high level. We devised a formalism of the parallel program design process to support space-based parallel program design. In this formalism, program designs are captured in entity spaces. Entity spaces, including data spaces, tasks, etc. can be subdivided and freely distributed into logical node clusters that are assigned to processes. We designed high-level communication channels for communication among divided subtasks in a parallel program for space-based communication integration. Supported program models range in single program multiple data, multiple program multiple data, and their hybrid model. We designed single-space and cross-space high-level communication channels with various communication topologies. They are specified externally and decoupled from a parallel program. This makes the program logical and easily designed and reused. A practical example is used for illustrating the design process.     

Birefringent properties of diametrically loaded gradient-index lenses

Gradient-index (GRIN) lenses have been widely used as collimators in various fiber-optic sensors and as optical coupling devices in components designed for optical communication systems. However, relatively little attention has been paid to the birefringent properties of GRIN lenses and the potential for using them as photoelastic sensing elements in optical transducers. Analytical and experimental results are described that were obtained for the intensity distribution produced by studying a GRIN lens by using a polariscope. The residual birefringence inherent in an unloaded lens is initially studied. The lens is then assumed to be diametrically loaded and the superposition is studied by the method of ray tracing. When the results obtained from the simulation for a Selfoc, 0.25-pitch lens are compared with experimental data, an excellent agreement is obtained. Intensity increases monotonically with load, confirming that the lens would be a good choice for the sensing element of an optical transducer designed as part of a strain or acceleration measurement system. The numerical simulation is then used to study the influence of residual stress on sensitivity.     

Orthogonal frequency coded filters for use in ultra-wideband communication systems

The use of ultra-short pulses, producing very wide bandwidths and low spectral power density, are the widely accepted approach for ultra-wideband (UWB) communication systems. This approach is simple and can be implemented with current digital signal processing technologies. However, surface acoustic wave (SAW) devices have the capability of producing complex signals with wide bandwidths and relatively high frequency operation. This approach, using SAW based correlators, eliminates many of the costly components that are needed in the IF block in the transmitter and receiver, and reduces many of the signal processing requirements. This work presents the development of SAW correlators using orthogonal frequency coding (OFC) for use in UWB spread spectrum communication systems. OFC and pseudonoise (PN) coding provide a means for UWB spreading of data. The use of OFC spectrally spreads a PN sequence beyond that of code division multiple access (CDMA) because of the increased bandwidth providing an improvement in processing gain. The transceiver approach is still very similar to that of a CDMA but provides greater code diversity. Experimental results of a SAW filter designed with OFC transducers are presented. The SAW correlation filter was designed using seven contiguous chip frequencies within the transducer. SAW correlators with a 29% fractional bandwidth were fabricated on lithium niobate (LiNbO3) having a center frequency of 250 MHz. A coupling-of-modes (COM) model is used to predict the SAW filter response experimentally and is compared to the measured data. Good correlation between the predicted COM responses and the measured device data is obtained. Discussion of the design, analysis, and measurements are presented. The experimental matched filter results are shown for the OFC device and are compared to the ideal correlation. The results demonstrate the OFC SAW device concept for UWB communication transceivers.     

Digital Processing and Communication with Molecular Switches

The tremendous pace in the development of information technology is rapidly approaching a limit. Alternative materials and operating principles for the elaboration and communication of data in electronic circuits and optical networks must be identified. Organic molecules are promising candidates for the realization of future digital processors. Their attractive features are the miniaturized dimensions and the high degree of control on molecular design possible in chemical synthesis. Indeed, nanostructures with engineered properties and specific functions can be assembled relying on the power of organic synthesis. In particular, certain molecules can be designed to switch from one state to another, when addressed with chemical, electrical, or optical stimulations, and to produce a detectable signal in response to these transformations. Binary data can be encoded on the input stimulations and output signals employing logic conventions and assumptions similar to those ruling digital electronics. Thus, binary inputs can be transduced into binary outputs relying on molecular switches. Following these design principles, the three basic logic operations (AND, NOT, and OR) and more complex logic functions (EOR, INH, NOR, XNOR, and XOR) have been reproduced already at the molecular level. Presently, these simple “molecular processors” are far from any practical application. However, these encouraging results demonstrate already that chemical systems can process binary data with designed logic protocols. Further fundamental studies on the various facets of this emerging area will reveal if and how molecular switches can become the basic components of future logic devices. After all, chemical computers are available already. We all carry one in our head!     

The use of a social network analysis technique to investigate the characteristics of crew communications in nuclear power plants—A feasibility study

Effective and reliable communications are very important in securing the safety of human-involved large process control systems because human operators have to accomplish their tasks in cooperative ways. This means that it is very important to understand the characteristics of crew communications, which can provide useful insights for preventing inappropriate communications. Unfortunately, in the nuclear industry, a systematic framework that can be used to identify the characteristics of crew communications seems to be rare. For this reason, the applicability of the social network analysis (SNA) technique to identifying the characteristics of crew communications was investigated in this study. To this end, the communication data of operating crews working in the main control room (MCR) of nuclear power plants (NPPs) were collected under two kinds of simulated off-normal conditions. Then the communication characteristics of MCR operating crews, which can be represented by the associated SNA metrics, were compared with communication characteristics that are already known from existing studies. As a result, it was found that SNA metrics could be meaningful for explaining the communication characteristics of MCR operating crews. Accordingly, it is expected that the SNA technique can be used as one of the serviceable tools to investigate the characteristics of crew communications in NPPs.     

SENORA: A P2P Service-Oriented Framework for Collaborative Multirobot Sensor Networks

SENORA is an open hardware and software architecture for the cooperative coordination of multiple heterogeneous mobile robots operating in a common environment. It is designed to meet the stringent requirements of modern loosely coupled multirobot architectures, such as flexibility, reliability, and fault tolerance. As such, the proposed architecture enables the robots to cope with the ubiquitous presence of various types of uncertainties in their operating environments. SENORA is a fully autonomous and scalable sensory-based peer-to-peer (P2P) framework. It also offers a real-time inter-robot communication protocol and it is based on the state-of-the-art P2P technology, which is specifically designed to satisfy the requirements of physical sensory data publishing and fusion. This architecture is implemented and evaluated on a team of indoor mobile robots. The test results manifest the architecture's distinguished features and capabilities     

Non-line-of-sight optical wireless sensor network operating in multiscattering channel

Networks of sensors are envisaged to be major participants in future data-gathering systems for civilian and military applications, including medical and environmental monitoring and surveillance, home security, agriculture, and industry. Typically, a very large number of miniature sensing and communicating nodes are distributed ad hoc at the location of interest, where they establish a network and wirelessly communicate sensed data either to one another or to a base station using various network topologies. The optical modality is a potential solution for the links, due to the small and lightweight hardware and low power consumption, as well as other special features. Notably, the backscattering of light by molecules and aerosols in the atmosphere can function as a vehicle of communication in a way similar to the deployment of numerous tiny reflecting mirrors. The scattering of light at solar-blind ultraviolet wavelengths is of particular interest since scattering by atmospheric particles is significant and ambient solar interference is minimal. In this paper we derive a mathematical model of a simple and low-cost non-line-of-sight (NLOS) optical wireless sensor network operating in the solar-blind ultraviolet spectral range. The viability and limitations of the internode link are evaluated and found to facilitate miniature operational sensor networks.     

Multilevel approach to lifetime assessment of steam turbines

This paper presents a multilevel methodology for a steam turbine lifetime assessment based on the damage calculation, probabilistic analysis and fracture mechanics considerations. Creep-fatigue damage calculations serve as a basis for evaluating the current lifetime expenditure and for defining additional steps of analysis. The need for the use of probabilistic analysis results from the inherent uncertainty in estimating the lifetime expenditure primarily caused by scatter in material properties. Fracture mechanics considerations are helpful in determining additional safety margins for components containing cracks. This methodology has been illustrated using an example of the lifetime calculations of a high-temperature steam turbine rotor. The calculations were based on the results of 2D numerical simulations performed for steady state and transient operating conditions.     

Evaluation of thermal imaging system and thermal radiation detector for real-time condition monitoring of high power frequency converters

We have carried out at laboratory test to study the feasibility of using thermal radiation detectors for online thermal monitoring of electrical systems in wind
turbines. A 25 kW frequency converter is instrumented with a thermal camera, operating in the 8–14 lm wavelength range, and a single-pixel thermopile sensor, operating in the 4–8 lm wavelength range, to monitor the temperature development of the power electronics under various load sequences. Both systems performed satisfactorily with insignificant temperature deviations when compared to data from calibrated point contact sensor. With spatial averaging over a 7 mm 9 7 mm for the camera and temporal averaging over 60 s for the thermopile sensor, we reduce the root mean square noise to 45 mK
and 68 mK respectively. The low cost and simple operation of the thermopile sensor make it very attractive for condition monitoring applications, whereas the attractive feature of the camera is the possibility of multi-point or distributed temperature measurements.     

Quality assurance of computed and digital radiography systems

Computed radiography (CR) and digital radiography (DR) are replacing traditional film screen radiography as hospitals move towards digital imaging and picture archiving and communication systems (PACS). Both IPEM and KCARE have recently published quality assurance and acceptance testing guidelines for DR. In this paper, the performance of a range of CR and DR systems is compared. Six different manufacturers are included. Particular attention is paid to the performance of the systems under automatic exposure control (AEC). The patient is simulated using a range of thicknesses of tissue equivalent material. Image quality assessment was based on detector assessment protocols and includes pixel value measures as well as subjective assessment using Leeds Test Objects. The protocols for detector assessment cover a broad range of tests and in general detectors (whether DR or CR) performed satisfactorily. The chief limitation in performing these tests was that not all systems provided ready access to pixel values. Subjective tests include the use of the Leeds TO20. As part of this work, suggested reference values are provided to calculate the TO20 image quality factor. One consequence of moving from film screen to digital technologies is that the dynamic range of digital detectors is much wider, and increased exposures are no longer evident from changes in image quality. As such, AEC is a key parameter for CR and DR. Dose was measured using a standard phantom as a basic means of comparing systems. In order to assess the AEC performance, exit doses were also measured while varying phantom thickness. Signal-to-noise ratios (SNRs) were calculated on a number of systems where pixel values were available. SNR was affected by the selection of acquisition protocol. Comparisons between different technologies and collation of data will help refine acceptance thresholds and contribute to optimising dose and image quality.     

Creep crack growth in power plant materials

Economic considerations have made it desirable to extend the 30 to 40 year operating life of power plants by another 10 to 20 years. Crack growth at elevated temperatures is an important consideration in estimating the remaining life, determining operating conditions and deciding inspection criteria and intervals for power plant materials. This paper presents an overview of high-temperature crack growth phenomenon in such materials. The focus is on various techniques used for characterizing creep crack growth (CCG) and creep-fatigue crack growth (CFCG) in high-temperature materials. The collection of data, their analysis and the interpretation of results is discussed in detail, especially for CFCG laboratory testing. The discussion is primarily focussed on creep-ductile materials such as those used in power plant applications. Special considerations for elevated temperature crack growth in weldments are also presented. Finally, the application of these concepts to the life prediction of power plant components is also discussed.     

Generation and Measurement of Phase Jitter Using Phase-Lock Techniques

The phase-locked loop (PLL) is applied to generating and measuring large phase jitter that can be encountered in digital transmission systems. It is shown that jitter can be generated and measured by a PLL operated as a phase modulator and phase demodulator, respectively. Equations and examples are given for practical PLL designs to generate and measure jitter of a certain amplitude range and bandwidth. Practical considerations such as 1) phase detector range, 2) limited voltage-controlled oscillator sensitivity, 3) frequency tolerances, 4) pull-in time, and 5) calibration are included. PLL's designed in this way can be useful in evaluating digital transmission systems. Jitter measuring sets have been designed to measure jitter on the 1.5, 6.3, 45, and 274 Mbit/s signals used in the LD-4 digital cable system [1]. A jitter set for measuring jitter on 45 Mbit/s signals is described in this paper.     

V-Shaped Monopole Antenna with Chichena Itzia Inspired Defected Ground Structure for UWB Applications

Due to rapid growth in wireless communication technology, higher bandwidth requirement for advance telecommunication systems, capable of operating on two or higher bands with higher channel capacities and minimum distortion losses is desired. In this paper, a compact Ultra-Wideband (UWB) V-shaped monopole antenna is presented. UWB response is achieved by modifying the ground plane with Chichen Itzia inspired rectangular staircase shape. The proposed V-shaped is designed by incorporating a rectangle, and an inverted isosceles triangle using FR4 substrate. The size of the antenna is 25 mm×26 mm×1.6 mm. The proposed V-shaped monopole antenna produces bandwidth response of 3 GHz Industrial, Scientific, and Medical (ISM), Worldwide Interoperability for Microwave Access (WiMAX), (IEEE 802.11/HIPERLAN band, 5G sub 6 GHz) which with an additional square cut amplified the bandwidth response up to 8 GHz ranging from 3.1 GHz to 10.6 GHz attaining UWB defined by Federal Communications Commission (FCC) with a maximum gain of 3.83 dB. The antenna is designed in Ansys HFSS. Results for key performance parameters of the antenna are presented. The measured results are in good agreement with the simulated results. Due to flat gain, uniform group delay, omni directional radiation pattern characteristics and well-matched impedance, the proposed antenna is suitable for WiMAX, ISM and heterogeneous wireless systems.     

Industrial applications of product design through the inversion of latent variable models

A methodology, presented by Jaeckle and MacGregor [C.M. Jaeckle and J.F. MacGregor, Product Design Through Multivariate Statistical Analysis of Process Data, AIChE J. 44 (5) (1998) 1105–1118.], for finding a window of process operating conditions within which a product with specified quality characteristics can be produced is applied to two industrial polymerization processes. The approach uses historical data available on the process operating conditions and on the corresponding product quality for a range of existing product grades. Latent variable models — built using the existing data — are inverted to obtain a window of operating conditions, which are not only capable of yielding the desired product but are also consistent with past operating procedures and constraints. A semi-batch emulsion polymerization process for manufacturing various grades of a copolymer latex, and a batch solution polymerization process for manufacturing a range of polymer resins are considered.     

可见光通信中LED非线性补偿和带宽拓展技术

可见光通信(VLC)是一项有前景的技术,作为现有无线通信网络的有益补充,可提供高速率、低延迟及多设备接入等通信服务。借助传统无线通信的高性能编码调制技术,已经设计并实现了各种适配于VLC系统的物理层通信技术。不同于传统射频通信,VLC采用LED作为信号的发射源,LED的调制容易产生非线性失真且调制带宽有限,已成为VLC高速通信的技术瓶颈。针对这两方面的挑战,本文以白光LED为出发点,阐述了白光LED能有效兼顾照明和通信的特性,总结和分类了非线性失真补偿和拓展调制带宽的多种技术,最后本文提出了LED封装材料及工艺、新型Micro-LED器件研究、光源布局设计、码间干扰消除技术等开放性研究问题,以期提高可见光通信系统的性能。