Effects of autophagy-inhibiting chemicals on sialylation of Fc-fusion glycoprotein in recombinant CHO cells.

The occurrence of autophagy in recombinant Chinese hamster ovary (rCHO) cell culture has attracted attention due to its effects on therapeutic protein production. Given the significance of glycosylation in therapeutic proteins, this study examined the effects of autophagy-inhibiting chemicals on sialylation of Fc-fusion glycoproteins in rCHO cells. Three chemical autophagy inhibitors known to inhibit different stages were separately treated with two rCHO cell lines that produce the same Fc-fusion glycoprotein derived from DUKX-B11 and DG44. All autophagy inhibitors significantly decreased the sialylation of Fc-fusion glycoprotein in both cell lines. The decrease in sialylation of Fc-fusion glycoprotein is unlikely to be attributed to the release of intracellular enzymes, given the high cell viability and low activity of extracellular sialidases. Interestingly, the five intracellular nucleotide sugars remained abundant in cells treated with autophagy inhibitors. In the mRNA expression profiles of 27 N-glycosylation-related genes using the NanoString nCounter system, no significant differences in gene expression were noted. With the positive effect of supplementing nucleotide sugar precursors on sialylation, attempts were made to enhance the levels of intracellular nucleotide sugars by supplying these precursors. The addition of nucleotide sugar precursors to cultures treated with inhibitors successfully enhanced the sialylation of Fc-fusion glycoproteins compared to the control culture. This was particularly evident under mild stress conditions and not under relatively severe stress conditions, which were characterized by a high decrease in sialylation. These results suggest that inhibiting autophagy in rCHO cell culture decreases sialylation of Fc-fusion glycoprotein by constraining the availability of intracellular nucleotide sugars. KEY POINTS: •  The autophagy inhibition in rCHO cell culture leads to a significant reduction in the sialylation of Fc-fusion glycoprotein. •  The pool of five intracellular nucleotide sugars remained highly abundant in cells treated with autophagy inhibitors. •  Supplementation of nucleotide sugar precursors effectively restores decreased sialylation, particularly under mild stress conditions but not in relatively severe stress conditions.

Clinical characteristics of COVID-19 patients treated in emergency COVID-19 hospitals in Vietnam: Experience from Phutho province, Vietnam.

Background: This study aimed to evaluate the clinical characteristics, patient's management approaches, and outcomes of the COVID-19 patients in Phu Tho Province, Vietnam. Methods: A retrospective, multicenter study of 2166 COVID-19 patients in 13 hospitals in Phutho Province, Vietnam. The subjects were divided into 3 groups based on vaccination status: unvaccinated group, 1st dose of vaccine group, 2nd dose of vaccine group. The clinical characteristics, management approaches, and outcomes were collected and compared between the 3 groups. Results: The hospitalization rate of the 3 groups decreased from the unvaccinated group, the 1st dose of vaccinated group, to the 2nd dose of vaccinated group, 42.61%; 30,24% and 27,15% respectively. The 19-40 years old group had the highest hospitalization rate (38,1%) together with the group that had not accepted the full COVID 19 vaccination dose (57,64%). The 2nd dose of vaccinated group had the lowest percentages of high temperature, cough, dyspnea, chest pain and sore throat. The unvaccinated group had the highest heart rate, respiratory rate and SpO2 compared to the two other groups. The percentage needing Immunomodulation and Anticoagulant Therapy was highest (6.8% and 1.4 % respectively) in the unvaccinated group. The percentage receiving Antiviral Therapy was highest (42,5%) in those who had received the 2nd dose of vaccine. Conclusions: COVID-19 vaccination improved the symptoms of the patients and should be accepted in all ages.

Artemisia argyi extract exerts antioxidant properties and extends the lifespan of Drosophila melanogaster.

BACKGROUND: Chinese mugwort (Artemisia argyi) possesses extensive pharmacological activities associated with anti-tumour, antioxidative and anti-inflammatory effects. The present study aimed to investigate the antioxidant and anti-ageing effects of A. argyi extract (AAE) on the fruit fly (Drosophila melanogaster) ageing model by detecting antioxidant enzyme activities and the mRNA level of antioxidant genes. RESULTS: AAE could significantly lengthen the mean lifespan, 50% survival days, and maximum lifespan of D. melanogaster, especially when the amount of AAE added reached 6.68 mg mL-1, the mean lifespan of both female and male flies increased by 23.74% and 22.30%, respectively, indicating the effective life extension effect of AAE. At the same time, AAE could improve the climbing ability and tolerance to hydrogen peroxide in D. melanogaster. In addition, the addition of AAE effectively increased the activities of copper-zinc-containing superoxide dismutase, manganese-containing superoxide dismutase and catalase in D. melanogaster and reduced the contents of malondialdehyde. Moreover, when reared with diets containing AAE, the expression of antioxidant-related genes SOD1, SOD2 and CAT was up-regulated in D. melanogaster and down-regulated for MTH genes. CONCLUSION: The study indicates that AAE effectively enhances the antioxidant capacity of D. melanogaster and has potential applications as an antioxidant and anti-ageing agent in the nutraceutical industry. © 2024 Society of Chemical Industry.

Impact of community health interventions on maternal and child health indicators in the upper east region of Ghana.

BACKGROUND: This paper reports on results of a health system strengthening implementation research initiative conducted the Upper East Region of northern Ghana. Transformative interventions to accelerate and strengthen the health delivery were implemented that included empowering community leaders and members to actively participate in health delivery, strengthening the referral systems through the provision of community transport systems, providing basic medical equipment to community clinics, and improving the skills of critical health staff through training. METHODS: A mixed method design was used to evaluate the impact of the interventions. A quantitative evaluation employed a flexible research design to test the effects of various component activities of the project. To assess impact, a pre-versus-post randomized cluster survey design was used. Qualitative research was conducted with focus group data and individual in depth interviews to gauge the views of various stakeholders associated with the implementation process. RESULTS: After intervention, significant improvements in key maternal and child health indicators such as antenatal and postnatal care coverage were observed and increases in the proportion of deliveries occurring in health facilities and assisted by skilled health personnel relative to pre-intervention conditions. There was also increased uptake of oral rehydration salts (ORS) for treatment of childhood diarrhoea, as well as marked reductions in the incidence of upper respiratory infections (URI). CONCLUSIONS: A pre-and post-evaluation of impact suggests that the programme had a strong positive impact on the functioning of primary health care. Findings are consistent with the proposition that the coverage and content of the Ghana Community-based Health Planning and Services programme was improved by program interventions and induced discernable changes in key indicators of health system performance.

Development of an in vitro screening system for synthetic signal peptide in mammalian cell-based protein production.

Optimizing appropriate signal peptides in mammalian cell-based protein production is crucial given that most recombinant proteins produced in mammalian cells are thought to be secreted proteins. Until now, most studies on signal peptide in mammalian cells have replaced native signal peptides with well-known heterologous signal peptides and bioinformatics-based signal peptides. In the present study, we successfully established an in vitro screening system for synthetic signal peptide in CHO cells by combining a degenerate codon-based oligonucleotides library, a site-specific integration system, and a FACS-based antibody detection assay. Three new signal peptides were screened using this new screening system, confirming to have structural properties as signal peptides by the SignalP web server, a neural network-based algorithm that quantifies the signal peptide-ness of amino acid sequences. The novel signal peptides selected in this study increased Fc-fusion protein production in CHO cells by increasing specific protein productivity, whereas they did not negatively affect cell growth. Particularly, the SP-#149 clone showed the highest qp, 0.73 ± 0.01 pg/cell/day from day 1 to day 4, representing a 1.47-fold increase over the native signal peptide in a serum-free suspension culture mode. In addition, replacing native signal peptide with the novel signal peptides did not significantly affect sialylated N-glycan formation, N-terminal cleavage pattern, and biological function of Fc-fusion protein produced in CHO cells. The overall results indicate the utility of a novel in vitro screening system for synthetic signal peptide for mammalian cell-based protein production. KEY POINTS: • An in vitro screening system for synthetic signal peptide in mammalian cells was established • This system combined a degenerate codon-based library, site-specific integration, and a FACS-based detection assay • The novel signal peptides selected in this study could increase Fc-fusion protein production in mammalian cells.

Travel decision determinants during and after COVID-19: The role of tourist trust, travel constraints, and attitudinal factors.

The COVID-19 pandemic has forced tourism practitioners to create efficient strategies to attract travelers. Using three theoretical frameworks, such as tourist trust (political, destination, and interactional trust), travel constraint (intrapersonal, interpersonal, and "social distancing" structural constraint), and extended theory of planned behavior (travel attitude, perceived behavioral control, subjective norm, perceived health risk, past travel experience), we develop a comprehensive framework to explain the impact of travel promoting, restricting, and attitudinal factors on travel decision during and after the pandemic. Data was obtained through an extensive survey conducted on 1451 Korean travelers and was analyzed using probabilistic choice models and count models. The results show the specific factors that determine travel decisions during the pandemic (whether to travel and frequency) and travel intention after the pandemic. This study provides important theoretical and practical insights into how to develop successful COVID-19 recovery strategies in the tourism industry.

Amplification of EBNA-1 through a single-plasmid vector-based gene amplification system in HEK293 cells as an efficient transient gene expression system.

Our previous work showed that there is a limitation in the use of dihydrofolate reductase (dhfr)/methotrexate (MTX)-mediated gene amplification systems in dhfr-non-deficient HEK293 cells, as endogenous dhfr may interfere with the amplification process. In the present study, we successfully generated Epstein-Barr virus nuclear antigen-1 (EBNA-1)-amplified HEK293 cells in a dhfr-non-deficient HEK293 cell background using a single-plasmid vector-based gene amplification system with shRNA targeting the 3'-UTR of endogenous dhfr. The introduction of this shRNA efficiently downregulated the expression of endogenous dhfr in the HEK293 cells without affecting exogenous dhfr expression. The downregulation of endogenous dhfr improved the efficiency of EBNA-1 amplification, as evidenced by a comparison with the amplification extent in cells lacking shRNA expression at the same MTX concentration. The EBNA-1 expression levels from the EBNA-1-amplified clones selected in this study were higher than those obtained from EBNA-1-amplified clones that were generated using the conventional amplification in our previous study. Consistent with previous studies, EBNA-1 amplification improved the production of the Fc-fusion protein through a specific protein productivity (qp)-enhancing effect, rather than by improving cell growth or transfection efficiency. In addition, the N-glycan profiles in the Fc-fusion protein produced using this transient gene expression (TGE) system were not affected by EBNA-1 amplification. These results indicate the potential utility of EBNA-1-amplified mammalian cells, developed using a single-plasmid vector-based gene amplification system, for efficient protein production. KEY POINTS: • EBNA-1-amplified HEK293 cells were established using gene amplification system. • EBNA-1 amplification in TGE system can increase the Fc-fusion protein productivity. • EBNA-1 amplification does not affect the N-glycan profile in the Fc-fusion protein.

Radiologic Analysis of Malar Arch Movement in Reduction Malarplasty Without Bony Resection.

BACKGROUND: Reduction malarplasty has been popular among Asians with a wide facial width. In general, malar setback after bony resection is regarded as the standard objective of reduction malarplasty. However, unnecessary bony resection may lead to various postoperative complications. Therefore, we suggest the use of reduction malarplasty without bony resection to achieve a similar narrowing effect of the facial width, based on radiographic analysis of malar arch movement. PATIENTS AND METHODS: This retrospective study analyzed 48 patients with a wide midface who underwent reduction malarplasty between September 2018 and December 2019. We included 40 cases of advancement repositioning malarplasty (AR) without bony resection and 8 cases of setback reduction malarplasty (SR) with bony resection. The three-dimensional position of the malar arch expressed by coordinates (x, y, and z) on three-dimensional computed tomography scans was used to compare the positional change between the surgical methods. The paired t-test, Wilcoxon text, and independent t-test were used in data analysis, and statistical analysis was performed using SPSS 23.0 software. RESULTS: Medial and superior movement of the freed malar arch segment was significantly different between AR and SR (P < 0.05). Although medialization and superiorization were not significantly different between AR and SR, there was a significant difference in anterior-posterior movement between AR and SR (P < 0.05). CONCLUSION: The radiologic analysis based on malar arch movement between AR and SR showed similar narrowing effects on medialization and superiorization of the malar arch regardless of bony resection. Therefore, the AR can be effectively applied in case of arch dominant type or malar asymmetry. In addition, further comprehensive study including analysis on movement of facial soft tissue following malar bony movement is expected based on this study in near future.

16 Ch × 200 GHz DWDM-Passive Optical Fiber Sensor Network Based on a Power Measurement Method for Water-Level Monitoring of the Spent Fuel Pool in a Nuclear Power Plant.

This paper presents a remote 16 Ch × 200 GHz dense wavelength division multiplexing (DWDM)-passive optical fiber sensor (OFS) network. We particularly investigate the remote water-level monitoring capability of the OFS network based on an optical power measurement that features simplicity and a fast processing speed. The OFS network utilizes a seeded amplified spontaneous emission (ASE) light that is spectrum-sliced and distributed by an arrayed waveguide grating (AWG) towards multiple sensing units (SU), where each SU is installed at a different height in the water pool. Then, each SU reflects either of the two different optical powers according to the medium (air vs. water) back to the monitoring station. Therefore, the total received optical power at the monitoring station linearly changes according to the water level. We can simply recognize the water level by utilizing the optical power meter (OPM) at the monitoring station rather than the optical spectrum analyzer (OSA), which is bulky and expensive and requires a relatively long processing time. Consequently, we can reduce the system complexity, processing time, and cost (both installation and maintenance). However, the OPM-based OFS network requires a new methodology to derive the water level from the measured optical power. Thus, we come up with the reference-to-power ratio (RPR) analysis, which can be used for the maximum distance analysis as well as water level recognition. Based on the new reception architecture supported by the new post-processing scheme, the OFS network can distinguish 17 different water levels of the SFP at the monitoring station, which is >40 km away from the SFP, without using any active devices (such as optical amplifiers) at the remote places.

Channel Allocation for Connected Vehicles in Internet of Things Services.

Based on the existing Internet of Vehicles communication protocol and multi-channel allocation strategy, this paper studies the key issues with vehicle communication. First, the traffic volume is relatively large which depends on the environment (city, highway, and rural). When many vehicles need to communicate, the communication is prone to collision. Secondly, because the traditional multi-channel allocation method divides the time into control time slots and transmission time slots when there are few vehicles, it will cause waste of channels, also when there are more vehicles, the channels will not be enough for more vehicles. However, to maximize the system throughput, the existing model Enhanced Non-Cooperative Cognitive division Multiple Access (ENCCMA) performs amazingly well by connected the Cognitive Radio with Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA) for a multi-channel vehicular network.However, this model induces Medium Access Control (MAC) overhead and does not consider the performance evaluation in various environmental conditions.Therefore, this paper proposes a Distributed Medium Channel Allocation (DMCA) strategy, by dividing the control time slot into an appointmentand a safety period in the shared channel network. SIMITS simulator was used for experiment evaluation in terms of throughput, collision, and successful packet transmission. However, the outcome shows that our method significantly improved the channel utilizationand reduced the occurrence of communication overhead.

Secure and Efficient High Throughput Medium Access Control for Vehicular Ad-Hoc Network.

The evolution of the internet has led to the growth of smart application requirements on the go in the vehicular ad hoc network (VANET). VANET enables vehicles to communicate smartly among themselves wirelessly. Increasing usage of wireless technology induces many security vulnerabilities. Therefore, effective security and authentication mechanism is needed to prevent an intruder. However, authentication may breach user privacy such as location or identity. Cryptography-based approach aids in preserving the privacy of the user. However, the existing security models incur communication and key management overhead since they are designed considering a third-party server. To overcome the research issue, this work presents an efficient security model namely secure performance enriched channel allocation (S-PECA) by using commutative RSA. This work further presents the commutative property of the proposed security scheme. Experiments conducted to evaluate the performance of the proposed S-PECA over state-of-the-art models show significant improvement. The outcome shows that S-PECA minimizes collision and maximizes system throughput considering different radio propagation environments.

Safety and effectiveness of minimally invasive scoliosis surgery for adolescent idiopathic scoliosis: a retrospective case series of 84 patients.

PURPOSE: The aim of this study was to retrospectively evaluate a prospective series of patients with adolescent idiopathic scoliosis (AIS) who were treated with minimally invasive scoliosis surgery (MISS) technique with a minimum follow-up more than 1 year. MATERIALS AND METHODS: We retrospectively analyzed the prospectively collected data of 84 patients with AIS treated with MIS technique using two or three coin hole size incisions and a muscle-splitting approach. The clinical and radiological data such as the correction of deformity, coronal and sagittal profile and record of the perioperative morbidity of the patients were analyzed. RESULTS: The mean primary Cobb angle was corrected from 59.8° preoperatively to 18.6° postoperatively with a mean correction of 68.9% (p < 0.001). The mean kyphosis at T2 to T12 was maintained within normal range with an increase from 31.2° preoperatively to 35.3° postoperatively (p < 0.001). The 30-day perioperative complication rate was 7.14% with one deep infection and five cases of hemothorax. The mean operation time was 312.8 min; mean estimated blood loss was 846.6 ml (range 420-2800); and mean length of stay was 8.5 days (range 5 to 14). All data of postoperative SRS-22 questionnaire were significantly improved (p < 0.001). CONCLUSION: MISS used for AIS provides adequate correction in both planes and acceptable rate of perioperative complications, with a low estimated blood loss and short length of stay. Considering all the positives, the application of MISS technique for AIS seems meaningful and can become a valid alternative to posterior approach in the routine use. These slides can be retrieved under Electronic Supplementary Material.

Multiplexed Passive Optical Fiber Sensor Networks for Water Level Monitoring: A Review.

Water management is a critical mission required to protect the water resources that is essential in diverse industrial applications. Amongst a variety of parameters such as level (or depth), temperature, conductivity, turbidity, and pH, the water level is the most fundamental one that needs to be monitored on a real-time basis for securing the water management system. This paper presents an overview of water level monitoring technologies based on optical fiber sensor (OFS) networks. Firstly, we introduce and compare the passive distributed and quasi-distributed (discrete) sensor networks with the recent achievements summarized. The performance (i.e., sensing range and resolution) of the OFS networks can be enhanced through diverse multiplexing techniques based on wavelength, time, coherence, space, etc. Especially, the dense wavelength division multiplexing (DWDM)-based sensor network provides remote sensing (where its reach can be extended to >40 km) with high scalability in terms of the channel number that determines the spatial resolution. We review the operation principle and characteristics of the DWDM-based OFS network with full theoretical and experimental analysis being provided. Furthermore, the key system functions and considerations (such as the link protection from physical damages, self-referencing, management of sensing units, and so on) are discussed that could be a guideline on the design process of the passive OFS network.

Long-Reach DWDM-Passive Optical Fiber Sensor Network for Water Level Monitoring of Spent Fuel Pool in Nuclear Power Plant.

This paper presents a passive optical fiber sensor network based on the dense wavelength division multiplexing (DWDM) to remotely monitor the water level of the spent fuel pool in nuclear power plants. In states of emergency, such as a tsunami, safety information must be secured for rapid response, in spite of all power losses in the plant. We consider the proposed passive sensor network to be one of the best solutions that is able to provide the remote (more than tens of kilometers) monitoring station with the highly reliable on-site information. The principle of water level measurement is based on the change of Fresnel reflection power coefficient at sensing units, which are installed according to the water levels in a row. The sensing units that play the role of reflector and modulator at the same time are connected to an arrayed waveguide grating (AWG) for DWDM. By measuring the spectrum of the optical signal transferred from the sensing units, the water level can be determined in real-time. However, in the remote sensing, the system performance can be seriously degraded due to the Rayleigh Back-Scattering (RBS) of the seeded amplified spontaneous emission (ASE) light that is induced at the fiber-optic link. As such, we investigate the effect of RBS on the remote (more than tens of kilometers) sensing performance of the proposed network. Following the theoretical analysis, we propose a simple network configuration to overcome the RBS issue by utilizing two different transmission paths: one for downstream of the ASE seed light, and the other for upstream of the optical signals coming from the sensing units. Based on the proposed configuration, the maximum sensing distance can be increased up to 42.5 km without the support of any optical amplifier.

A Secure Enhanced Non-Cooperative Cognitive Division Multiple Access for Vehicle-to-Vehicle Communication.

The growth of the Internet has led to the increasing usage of smart infotainment applications on the vehicular ad-hoc network (VANET). Preserving privacy and security regarding the provision of smart infotainment applications while on the go is most desired. Thus, a secure authentication scheme is required. Many privacy-preserving security schemes have been developed in recent times using cryptography approaches. However, these incur key management and communication overhead. The usage of third-party servers incurs the overhead of key computation, storage and distribution. Post completion of the initialization phase, the message is secured using cryptography and is shared among vehicles. The design of the proposed secure enhanced non-cooperative cognitive division multiple access ( S - ENCCMA ) aims to eliminate the need for the local message available with the parties to be released for provisioning secure safety-related applications. To overcome the research challenges, this work presents a novel security scheme, namely secure non-cooperative cognitive medium access ( S - ENCCMA ). The experiment is conducted to evaluate the overhead incurred in provisioning security to ENCCMA . The outcome shows that the overhead incurred by S - ENCCMA over ENCCMA was negligible to provide the real-time security requirements of smart infotainment applications, which is experimentally shown in this paper in terms of throughput, collision and successful packet transmission considering varied environmental models such as cities, highways and rural areas.

Delayed presentation of infected common iliac artery pseudoaneurysm caused by malpositioned pedicle screw after minimally invasive scoliosis surgery.

PURPOSE: To report delayed onset common iliac artery perforation and infected pseudoaneurysm caused by malpositioned pedicle screw after minimally invasive scoliosis surgery (MISS). METHODS: A 21-year-old female was referred to our hospital with a 1-week history of abrupt right-sided low back pain, lower abdominal pain, and fever with a history of MISS using cannulated pedicle screws 18 months earlier. Paravertebral arterial erosion with pseudoaneurysm and retroperitoneal and paraspinal abscess were suspected. RESULTS: We performed resection of the pseudoaneurysm, vascular repair of right common iliac artery by angioplasty with a bovine patch and removal of implant. At 6 months after the last surgery, she had no limitations or problems in her daily activities with no recurrence of low back pain, abdominal pain, or fever as well as without loss of deformity. CONCLUSIONS: Our case showed that misplaced pedicle screws can cause potentially fatal complications, such as infected pseudoaneurysm, even in the late postoperative period.

A Simple All-Optical Water Level Monitoring System Based on Wavelength Division Multiplexing with an Arrayed Waveguide Grating.

We propose and demonstrate a simple water level monitoring system based on the wavelength division multiplexing (WDM) for the spent fuel pool (SFP) at a nuclear power plant. The basic principle is based on the measurement of the optical power spectra by the Fresnel reflection according to the change of the refractive index at the end facet of the optical fiber tip (OFT). An arrayed waveguide grating (AWG) is employed to achieve multi-channel sensing capability with a C-band broadband light source (BLS) based on amplified spontaneous emission (ASE). The feasibility of the proposed scheme is investigated with a simulation and experimentation. We also investigate the limiting factor for remote transmission. The system performance is degraded by the Rayleigh backscattering of the BLS light, but it can be operated over long distances within 10 km with 5 dB of difference peak power margin.

Performance Enriching Channel Allocation Algorithm for Vehicle-to-Vehicle City, Highway and Rural Network.

Future safety applications require the timely delivery of messages between vehicles. The 802.11p has been standardized as the standard Medium Access Control (MAC) protocol for vehicular communication. The 802.11p uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) as MAC. CSMA/CA induces unbounded channel access delay. As a result, it induces high collision. To reduce collision, distributed MAC is required for channel allocation. Many existing approaches have adopted Time Division Multiple Access (TDMA) based MAC design for channel allocation. However, these models are not efficient at utilizing bandwidth. Cognitive radio technique is been adopted by various existing approach for channel allocation in shared channel network to maximize system throughput. However, it induces MAC overhead, and channel allocation on a shared channel network is considered to be an NP-hard problem. This work addresses the above issues. Here we present distributed MAC design PECA (Performance Enriching Channel Allocation) for channel allocation in a shared channel network. The PECA model maximizes the system throughput and reduces the collision, which is experimentally proven. Experiments are conducted to evaluate the performance in terms of throughput, collision and successful packet transmission considering a highly congested vehicular ad-hoc network. Experiments are carried out to show the adaptiveness of proposed MAC design considering different environments such City, Highway and Rural (CHR).

Deep learning based transceiver design for multi-colored VLC systems.

This paper presents a deep-learning (DL) based approach to the design of multi-colored visible light communication (VLC) systems where RGB light-emitting diode (LED) lamps accomplish multi-dimensional color modulation under color and illuminance requirements. It is aimed to identify a pair of multi-color modulation transmitter and receiver leading to efficient symbol recovery performance. To this end, an autoencoder (AE), an unsupervised deep learning technique, is adopted to train the end-to-end symbol recovery process that includes the VLC transceiver pair and a channel layer characterizing the optical channel along with additional LED intensity control features. As a result, the VLC transmitter and receiver are jointly designed and optimized. Intensive numerical results demonstrate that the learned VLC system outperforms existing techniques in terms of the average symbol error probability. This framework sheds light on the viability of DL techniques in the optical communication system design.

Binary signaling design for visible light communication: a deep learning framework.

This paper develops a deep learning framework for the design of on-off keying (OOK) based binary signaling transceiver in dimmable visible light communication (VLC) systems. The dimming support for the OOK optical signal is achieved by adjusting the number of ones in a binary codeword, which boils down to a combinatorial design problem for the codebook of a constant weight code (CWC) over signal-dependent noise channels. To tackle this challenge, we employ an autoencoder (AE) approach to learn a neural network of the encoder-decoder pair that reconstructs the output identical to an input. In addition, optical channel layers and binarization techniques are introduced to reflect the physical and discrete nature of the OOK-based VLC systems. The VLC transceiver is designed and optimized via the end-to-end training procedure for the AE. Numerical results verify that the proposed transceiver performs better than baseline CWC schemes.