Optical domain service differentiation using spectral-amplitude-coding

We have implemented a new service differentiation technique in the optical domain using a spectral-amplitude-coding (SAC) variant of optical code division multiple access (OCDMA). The newly developed code, named KS (Khazani–Syed) is compared mathematically with other codes which use similar techniques. In our proposal, multiple weights are used to support ‘triple-play’ services (audio, video and data) with different quality-of-service (QoS) requirements. The results characterizing the bit-error-rate (BER) with respect to the total number of active users show that KS offers a significantly improved performance over the previous reported techniques by accommodating additional 30 users with shorter code length and smaller code weight at BER of 10^?9. In variable weight system, we have shown that KS codes with larger weight always have the best performance when other users of different weights are present in the system.     

Realization of high capacity transmission in fiber optic communication systems using Absolute Polar Duty Cycle Division Multiplexing (AP-DCDM) technique

An electrical multiplexing technique, namely Absolute Polar Duty Cycle Division Multiplexing (AP-DCDM) is reported for high-speed optical fiber communication systems. It is demonstrated that 40 Gb/s (4 × 10 Gb/s) AP-DCDM system shows a clear advantage over conventional 40 Gb/s RZ-OOK with 50% duty cycle in terms of dispersion tolerance and spectral efficiency. At 40 Gb/s its tolerance to chromatic dispersion (CD) is 124 ps/nm and 194 ps/nm for the worst and the best user, respectively. These values are higher than that of 40 Gb/s RZ-OOK, which is around 100 ps/nm. The spectral efficiency, receiver sensitivity and OSNR for different number of channels are discussed. Comparison against other modulation formats namely duobinary, Non-Return-to-Zero (NRZ)-OOK and RZ-Differential Quadrature Phase-Shift Keying (RZ-DQPSK) at 40 Gb/s are made. It is shown that AP-DCDM has the best receiver sensitivity (−32 dBm) and better CD tolerance (±200 ps/nm) than NRZ-OOK and RZ-DQPSK. In reference to duobinary, AP-DCDM has better receiver sensitivity but worse dispersion tolerance.     

Electrochemical stability of PEDOT for wearable on-skin application

Conducting polymers are promising candidates for wearable devices due to mechanical flexibility combined with electroactivity. While electrochemical measurements have been adopted as a central transduction method in many on-skin sensors, less studied is the stability of the active materials (in particular poly3,4-ethylenedioxythiophene, PEDOT) in such systems, particularly for “on-skin” applications. In this study, several different variants of doped PEDOT are fabricated and characterized in terms of their (electrical, physical, and chemical) stability in biological fluid. PEDOT doped with tosylate (TOS) or polystyrenesulfonate (PSS) are selected as prototypical forms of conducting polymers. These are compared with a new variant of PEDOT co-doped with both TOS and PSS. Artificial interstitial fluid (aISF) loaded with 1% wt/vol bovine serum albumin is adopted as the testing medium to demonstrate the stability in dermal applications (i.e., conducting polymer microneedles or coatings on microneedles). A range of techniques such as cyclic voltammetry and electrochemical impedance spectroscopy are used to qualify and quantify the stability of the doped conducting polymers. Furthermore, this study is extended by using human skin lysate in the aISF to demonstrate proof-of-concept for stable use of PEDOT in wearable “on-skin” electronics.     

Correction to: An Enhanced Cooperative Communication Scheme for Physical Uplink Shared Channel in NB‑IoT

Wireless Personal Communications - There were errors in the first and fourth authors' names in the initial online publication. The original article has been corrected.     

More Relaxed Non‐Quadratic Stabilization Conditions Using Ts Open Loop System and Control Law Properties

This paper proposes more relaxed stabilization conditions based on a non‐quadratic Lyapunov function (NQLF) and parallel distributed compensator (PDC) controller. The conditions are derived in terms of linear matrix inequalities (LMIs) by introducing three slack matrices based on the properties of TS membership functions, an open loop system and a PDC controller. These slack matrices are utilized to decouple the LMI variables from the TS system and the input matrices. Therefore, the proposed approach greatly reduces the number of LMI conditions and improves feasibility by providing more degrees of freedom compared to recently published studies. Moreover, local stability and stabilization conditions are considered to handle the time derivatives of membership functions appearing in the stabilization synthesis of the TS closed‐loop system with PDC controller. Finally, several examples are presented to demonstrate the advantages of the proposed approaches.     

Non-destructive evaluation of the internal fruit quality of black mulberry (Morus nigra L.) using visible-infrared spectroscopy and genetic algorithm

The present study aims at assessing a non-destructive optical method for determining the internal quality of mulberry juice. First, UV-IR spectra (300–1100 nm) were acquired for each sample with a spectral resolution of 2 nm. Then the calibration set, composed of 70 and 38 samples, was used as the validation set. Next, two types of pre-processing multiplicative scatter correction)MSC(and standard normal variate)SNV(were used before analysing the data with multivariate calibration methods of PLS and GA-PLS. The following results were obtained including the correlation coefficient (r) of 0.94, 0.89, 0.98, and 0.95 and root mean square error of validation (RMSEV) 1.31°Brix, 0.52, 0.014, and 0.014 for total soluble solid (TSS), titratable acidity (TA), ascorbic acid (AA), and total anthocyanin content (AC) of mulberry juice, respectively. After that, GA-PLS was applied to select the efficient spectral regions. Model using 31 variables and 15 factors presented and yielded the best prediction results. The best combinations of 21 spectral intervals among 40 intervals selected by GA-PLS also yielded good results with RMSEV = 0.03096, r = 0.96; RMSEV = 0.062, r = 0.98, RMSEV = 0.041, r = 0.98; RMSEV = 0.0006, r = 0.96 for TSS, AA, TA, and AC of mulberry juice, respectively. Finally, it was concluded that using the UV-IR measurement technique, spectral range (300–1100 nm), it was possible to assess the quality characteristics of mulberry juice.     

Imaging internal features of whole, unfixed bacteria

Wet scanning-transmission electron microscopy (STEM) is a technique that allows high-resolution transmission imaging of biological samples in a hydrated state, with minimal sample preparation. However, it has barely been used for the study of bacterial cells. In this study, we present an analysis of the advantages and disadvantages of wet STEM compared with standard transmission electron microscopy (TEM). To investigate the potential applications of wet STEM, we studied the growth of polyhydroxyalkanoate and triacylglycerol carbon storage inclusions. These were easily visible inside cells, even in the early stages of accumulation. Although TEM produces higher resolution images, wet STEM is useful when preservation of the sample is important or when studying the relative sizes of different features, since samples do not need to be sectioned. Furthermore, under carefully selected conditions, it may be possible to maintain cell viability, enabling new types of experiments to be carried out. To our knowledge, internal features of bacterial cells have not been imaged previously by this technique.