Holograms in Optical Wireless Communications

Adaptive beam steering in optical wireless communication (OWC) system has been shown to offer performance enhancements over traditional OWC systems. However, an increase in the computational cost is incurred. In this chapter, we introduce a fast hologram selection technique to speed up the adaptation process. We propose a fast delay, angle and power adaptive holograms (FDAPA-Holograms) approach based on a divide and conquer methodology and evaluate it with angle diversity receivers in a mobile optical wireless (OW) system. The fast and efficient fully adaptive FDAPA-Holograms system can improve the receiver signal to noise ratio (SNR) and reduce the required time to estimate the position of the receiver. The adaptation techniques (angle, power and delay) offer a degree of freedom in the system design. The proposed system FDAPA-Holograms is able to achieve high data rate of 5 Gb/s with full mobility. Simulation results show that the proposed 5 Gb/s FDAPA-Holograms achieves around 13 dB SNR under mobility and under eye safety regulations. Furthermore, a fast divide and conquer search algorithm is introduced to find the optimum hologram as well as to reduce the computation time. The proposed system (FDAPA-Holograms) reduces the computation time required to find the best hologram location from 64 ms using conventional adaptive system to around 14 ms

Uplink Design in VLC Systems with IR Sources and Beam Steering

The need for high-speed local area networks to meet the recent developments in multimedia and video transmission applications has recently focused interest on visible light communication (VLC) systems. Although VLC systems provide lighting and communications simultaneously from light emitting diodes, LEDs, the uplink channel design in such a system is a challenging task. In this paper, we propose a solution in which the uplink challenge in indoor VLC is resolved by the use of an Infrared (IR) link. We introduce a novel fast adaptive beam steering IR system (FABS-IR) to improve the uplink performance at high data rates while providing security for applications. The goal of our proposed system is to enhance the received optical power signal, speed up the adaptation process and mitigate the channel delay spread when the system operates at a high transmission rate. The channel delay spread is minimised from 0.22 ns given by hybrid diffuse IR link to almost 0.07 ns. At 2.5 Gb/s, our results show that the imaging FABS-IR system accomplished about 11.7 dB signal to noise ratio (SNR) in the presence of multipath dispersion, receiver noise and transmitter mobility

Step and Step-Nc as a Tool for Big Data in Cloud Manufacturing

The terms big data, cloud manufacturing, predictive and additive manufacturing, and Internet of Things (IoT) are being most commonly used in the manufacturing industry nowadays. These terms are related to the fourth industrial revolution that emphasizes automation and data exchange between manufacturing tools/elements. Communication occurs between machines, products and even technicians or operators through various technologies while creating records of each interaction resulting in rapid growth of amount of data to be stored. Data acquisition is not a major issue since a structure or framework can properly connect these data in improving manufacturing efficiency. However, lack of effort in collecting and storing manufacturing data in the whole product life cycle process has made integration to be almost difficult to achieve. In this study, the adoption of STEP-NC method/technique was demonstrated in suiting the current explosion of big data in the industrial and manufacturing sector. The proposed methodology was developed through a study of an entity file structure and hierarchical concept in STEP and STEP-NC in gathering manufacturing data in a unified database. The challenge would be in making sense of the data, revealing the patterns in it and using them for operational improvements. The outcome of this study will be useful to support strategic decision making in product manufacturing

Control of an underactuated double-pendulum overhead crane using improved model reference command shaping: Design, simulation and experiment

This paper presents a new control scheme based on model reference command shaping (MRCS) for an overhead crane, with double-pendulum mechanism effects. The approach has an advantage in achieving an accurate trolley positioning, with low hook and payload oscillations, under various desired trolley positions and parameter uncertainties, without the requirement for measurement or estimation of system parameters. These are challenging in practice. The previously developed MRCS algorithm is improved in order to reduce its design complexity, as well as to ensure that it can be augmented with a feedback controller so that a concurrent controller tuning can be realised. The combined MRCS and feedback controller is used to achieve both, precise trolley positioning, and low hook and payload oscillations. To evaluate the effectiveness and the robustness of the approach, simulations and experiments using a nonlinear model and a laboratory double-pendulum crane are carried out. Under various desired positions and parameter uncertainties that involve varying the cable lengths (payload hoisting) and the payload mass variations, the superiority of the proposed approach is confirmed by achieving higher hook and payload oscillation reductions when compared with a recently proposed feedback controller. In addition, the desired trolley positions are achieved with smoother responses

Greening Big Data Networks: Velocity Impact

The authors investigate the impact of big data's velocity on greening IP over WDM networks. They classify the processing velocity of big data into two modes: expedited-data and relaxed-data modes. Expedited-data demands higher amount of computational resources to reduce the execution time compared with the relaxed-data. They developed a mixed integer linear programming model to progressively process big data at strategic locations, dubbed processing nodes (PNs), built into the network along the path from the source to the destination. The extracted information from the raw traffic is smaller in volume compared with the original traffic each time the data is processed, hence, reducing network power consumption. The results showed that up to 60% network power saving is achieved when nearly 100% of the data required relaxed processing. In contrast, only 15% of network power saving is gained when nearly 100% of the data required expedited processing. The authors obtained around 33% power saving in the mixed modes (i.e. when ∼50% of the data is processed in the relaxed mode and 50% of the data is processed in expedited mode), compared with the classical approach where all the processing is achieved inside the centralised data centres only

Analysis of WiMAX Positioning Using Received-Signal-Strength Method

This paper presents an analysis of WiMAX positioning by using received-signal-strength (RSS) method. A simulator was developed using MATLAB to demonstrate the ability of RSS method for WiMAX positioning. With this simulator, the user can specify their own data or parameters in analyzing and obtaining the target object location. In this study, the analysis was done in three different scenarios that simulate various conditions for WiMAX positioning. Result shows that channel or propagation models are crucial part in the process of analyzing the communication system where it will affect the performance of positioning detection. Selection of perfect model that resemble the real environment will led to better wireless positioning system. By the performance evaluation, the user can plan better simulation system and can create more accurate algorithms for radio positionin

ND5 gene marker reveals recent population expansion of wild Pearse’s mudskipper (Periophthalmus novemradiatus Hamilton) inhabits Setiu Wetlands in East Peninsular Malaysia

Genetic variation and differences in wild Pearse’s mudskipper Periophthalmus novemradiatus populations from Setiu Wetlands in East Peninsular Malaysia were analysed using the partial mitochondrial DNA ND5 gene sequences. Among the 91 individuals sampled from six different localities, 35 novel putative haplotypes of P. novemradiatus were detected. 77% (27) of the haplotypes were unique sequences, with high level of haplotype diversity (H = 0.875) and low nucleotide diversity (π = 0.0037), contributing to the overall highly diversified gene pool of the P. novemradiatus. This reflects a large effective population size with current population expansion, which allows the retention of new alleles in populations. However, due to insufficient time, the accumulation of deeper divergent groups among haplotypes was not possible. Hap05 is the most dominant (33%) and widespread haplotype, followed by Hap11 and 31. Low genetic differentiation with high gene flow was detected between sampling sites, and no pattern for isolation by distance was observed despite being territorial creatures. All sites are at the top priority for conservation because they possess unique haplotypes that are only present at the respective location. Further samples collection from other native regions are required to provide full understanding of its genetic distribution and phylogeographical study over larger scale of geographic regions. Heuristic approach to study other species in this area prior to gazetting the Setiu Wetlands as state park is required in order to conserve the biodiversity in-situ

Influence Of Point And Helix Angle On Thrust Force And Delamination For One-Shot Drilling Of Carbon Fiber Reinforced Plastic (CFRP)

Drilling operation for CFRP parts in the aircraft industry assembly line is unavoidable. Delamination frequently occurs during drilling holes in CFRP and reduces the ability of CFRP parts to carry loads and affects its service life spend. Drill reamer is enhancing the drill bits option for oneshot drilling to save time and cost. This article aims to investigate the influence on the variation of point and helix angle of drill reamer to thrust force and delamination damage. Different drills with the variation of point and helix angle were used to drill unidirectional CFRP laminates panel separately. From the thrust force curve graph, drilling using drill reamer can be divided into three main stages. Point angle geometrical feature influence in stage I while, helix angle in stage III, whereas stage II act as an opener for the drilled hole. Its found that point angle in drill reamer act as pilot drill and helix angle significantly affect to drilled holes quality. Variation of point angle features affected the thrust force measurement for stage I of drilling. The minor righthand side helix angle reduces the delamination compared to straight flute but negatively affected when major helix angle applied. The suitable combination of drill reamers’ geometry features will enhance overall drilling qualities

Band-pass filter-like antenna validation in an ultra-wideband in-car wireless channel

Ultra-wide band (UWB) is a very attractive technology for innovative in-car wireless communications requiring high data rates. A designated antenna, which presents a reflection coefficient (S11) matched band comparable to the Band Pass Filters (BPF) normally required at the transducers, plays a positive contribution in this in-car application and was validated for the scenario. The inherited BPF-like response of the antenna relaxes the specification of the front-end BPF components of the transceivers. The in-car propagation channel was modelled and used to validate the BPF-like antenna. For the modelling, a comprehensive set of well-defined measurements (using a standard antenna) were used to set-up the in-car channel simulator and simulated results were used to validate the BPF-like antenna. Additionally, the performance of the UWB radio system is studied and the probability of errors over the communication channel compared using the standard and the BPF-like antenna by predictions

WDM for Multi-user Indoor VLC Systems with SCM

A system that employs wavelength division multiplexing (WDM) in conjunction with subcarrier multiplexing (SCM) tones is proposed to realize high data rate multi-user indoor visible light communication (VLC). The SCM tones, which are unmodulated signals, are used to identify each light unit, to find the optimum light unit for each user and to calculate the level of the co-channel interference (CCI). WDM is utilized to attain a high data rate for each user. In this paper, multicolour (four colours) laser diodes (LDs) are utilized as sources of lighting and data communication. One of the WDM colours is used to convey the SCM tones at the beginning of the connection to set up the connection among receivers and light units (to find the optimum light unit for each user). To evaluate the performance of our VLC system, we propose two types of receivers: an array of non-imaging receivers (NI-R) and an array of non-imaging angle diversity receivers (NI-ADR). In this paper, we consider the effects of diffuse reflections, CCI and mobility on the system performance