Utilization of Reflective Semiconductor Optical Amplifier (RSOA) for Multiwavelength and Wavelength-Tunable Fiber Lasers

In this chapter, there are three sections to demonstrate the reflective semiconductor optical amplifier (RSOA)-based fiber laser architectures for multiwavelength and wavelength-tunable operations. In the first section, we introduce an L-band multiwavelength laser by utilizing a C-band RSOA with a linear cavity, which is produced by a polarization controller (PC), an optical coupler (OCP), and a reflected fiber mirror (RFM). In the proposed RSOA laser scheme, two to seven wavelengths could be lased and created simultaneously in the L-band range, while the RSOA operates at various bias currents

Phosphor-LED-Based Wireless Visible Light Communication (VLC) and Its Applications

In this chapter, we review our recent works on the phosphor white‐light light‐emitting diode (LED)-based wireless visible light communication (VLC) and its applications. This chapter is divided into two sections for introduction. In the first section, in order to enhance the transmission rate in phosphor-LED VLC system, we propose and demonstrate a novel multiband orthogonal-frequency-division-multiplexed (OFDM) modulation format for capacity enhancement. Based on the proposed scheme, various bands of OFDM signals are employed to different LED chips of the LED luminary; it can prevent the power fading and nonlinearity effects of transmission signal. Therefore, the maximum enhanced percentage of VLC data rate is 41.1%. In the second section, we also demonstrate a 71.3–148.4 Mbps phosphor-LED wireless VLC system at the free space transmission distance between 1.4 and 2.1 m. Finally, to understand and demonstrate the real-time LED VLC transmission, a commercial OFDM-based digital signal processor (DSP) is used in the LED transmitting side and client side, respectively. Therefore, the proposed real-time half-duplex VLC system can complete around 70 Mbps downstream and upstream traffic throughputs, in a free space transmission distance of 2 m long for practical in-home illumination and smart city applications

Attitudes of Acutely Ill Patients Towards Euthanasia in Hong Kong

The global euthanasia debate by health care professionals has raised important ethical issues concerning the professional duties and responsibilities of nurses caring for terminal patients. The purpose of this study was to examine the attitudes of acutely ill patients towards the practice of euthanasia in Hong Kong. A modified form of the 23-item Questionnaire for General Household Survey scale was used. This cross-sectional survey study was conducted with a stratified sample of in-patients recruited from a wide variety of departments in a regional, acute general hospital. Seventy-seven out of 129 patients responded (59.7%) and a high proportion of patients agreed with the use of euthanasia in the following circumstances: ‘where they were a third party’, if ‘someone they loved’ was affected, or if ‘they themselves were the patient’. Of the 77 patients, 54 agreed with active euthanasia (70.1%) and 65 with passive (84.4%). The results also indicated that a few socio-demographic characteristics (such as age, gender and household income) statistically significantly correlated with patients’ attitudes towards euthanasia. These findings highlight that Chinese patients with acute illness generally accept the use of euthanasia. Further research on the attitudes and perceptions of patients towards the use of euthanasia is recommended, particularly in diverse groups of Chinese and Asian patients with acute or terminal illness

Contrastive Speaker Embedding With Sequential Disentanglement

Contrastive speaker embedding assumes that the contrast between the positive and negative pairs of speech segments is attributed to speaker identity only. However, this assumption is incorrect because speech signals contain not only speaker identity but also linguistic content. In this paper, we propose a contrastive learning framework with sequential disentanglement to remove linguistic content by incorporating a disentangled sequential variational autoencoder (DSVAE) into the conventional SimCLR framework. The DSVAE aims to disentangle speaker factors from content factors in an embedding space so that only the speaker factors are used for constructing a contrastive loss objective. Because content factors have been removed from the contrastive learning, the resulting speaker embeddings will be content-invariant. Experimental results on VoxCeleb1-test show that the proposed method consistently outperforms SimCLR. This suggests that applying sequential disentanglement is beneficial to learning speaker-discriminative embeddings.Comment: Submitted to ICASSP 202

Drawing guessing game for the elderly

Drawing guessing game is the game where the users are required to guess the item that is progressively drawn on the screen. In this project, an elderly oriented mobile drawing guessing game named Guess It was developed. This application allows the drawings to be added into the cloud database from time to time and get downloaded to the user’s mobile devices without the need to update the application. The time taken to complete each game can be recorded to monitor the progress of the elderlies who plays the game. The aim of this project is to develop an elderly friendly mobile game by incorporating the elderly gaming design guidelines and by considering the elderly’s limitations, to foster the interest of the elderly in mobile gaming. Survey was carried out with a group of elderlies at the end of the project to gauge their confidence and satisfaction level in the developed game

Bracketing in Phenomenology: Only Undertaken in the Data Collection and Analysis Process

Our aim with this article is to demonstrate how the researchers use bracketing as a method of demonstrating the validity after initiating a phenomenological study. Although bracketing is a method of demonstrating the validity of the da ta collection and analysis process in most phenomenological studies, how the researchers use them in practice is rarely demonstrated explicitly. We collected data through our experiences in preparing a phenomenological research study. We suggest that the concept of bracketing should be adopted upon initiating the research proposal and not merely in the data collection and analysis process. We propose four strategies for doing bracketing that are guided by the thinking activity of reflexivity: mentality assessment and preparation before deciding the research paradigm, deciding the scope of the literature review according to the prevailing gate - keeping policy, planning for data collection using semi - structured interviews guided by open - ended questions, and planning for data analysis using Colaizzi’s method. Our proposition highlights that thorough preparation for doing bracketing is essential before entering the data collection and analysis process in phenomenology, because they are sequentially related

Insights of biosurfactant producing Serratia marcescens strain W2.3 isolated from diseased tilapia fish: a draft genome analysis

Background Serratia marcescens is an opportunistic bacterial pathogen with broad range of host ranging from vertebrates, invertebrates and plants. S. marcescens strain W2.3 was isolated from a diseased tilapia fish and it was suspected to be the causal agent for the fish disease as virulence genes were found within its genome. In this study, for the first time, the genome sequences of S. marcescens strain W2.3 were sequenced using the Illumina MiSeq platform. Result Several virulent factors of S. marcescens such as serrawettin, a biosurfactant, has been reported to be regulated by N-acyl homoserine lactone (AHL)-based quorum sensing (QS). In our previous studies, an unusual AHL with long acyl side chain was detected from this isolate suggesting the possibility of novel virulence factors regulation. This evokes our interest in the genome of this bacterial strain and hereby we present the draft genome of S. marcescens W2.3, which carries the serrawettin production gene, swrA and the AHL-based QS transcriptional regulator gene, luxR which is an orphan luxR. Conclusion With the availability of the whole genome sequences of S. marcescens W2.3, this will pave the way for the study of the QS-mediated genes expression in this bacterium

Asymmetric Clean Segments-Guided Self-Supervised Learning for Robust Speaker Verification

Contrastive self-supervised learning (CSL) for speaker verification (SV) has drawn increasing interest recently due to its ability to exploit unlabeled data. Performing data augmentation on raw waveforms, such as adding noise or reverberation, plays a pivotal role in achieving promising results in SV. Data augmentation, however, demands meticulous calibration to ensure intact speaker-specific information, which is difficult to achieve without speaker labels. To address this issue, we introduce a novel framework by incorporating clean and augmented segments into the contrastive training pipeline. The clean segments are repurposed to pair with noisy segments to form additional positive and negative pairs. Moreover, the contrastive loss is weighted to increase the difference between the clean and augmented embeddings of different speakers. Experimental results on Voxceleb1 suggest that the proposed framework can achieve a remarkable 19% improvement over the conventional methods, and it surpasses many existing state-of-the-art techniques.Comment: 5 pages, 2 figures, submitted to ICASSP 202