New Delay Doppler Communication Paradigm in 6G Era:A Survey of Orthogonal Time Frequency Space(OTFS)

In the 6G era,Space-Air-Ground Integrated Network(SAGIN)are anticipated to deliver global coverage,necessitating support for a diverse array of emerging applications in high-mobility,hostile environments.Under such conditions,conventional orthogonal frequency division multiplexing(OFDM)modulation,widely employed in cellular and Wi-Fi communication systems,experiences performance degradation due to significant Doppler shifts.To overcome this obstacle,a novel twodimensional(2D)modulation approach,namely orthogonal time frequency space(OTFS),has emerged as a key enabler for future high-mobility use cases.Distinctively,OTFS modulates information within the delay-Doppler(DD)domain,as opposed to the timefrequency(TF)domain utilized by OFDM.This offers advantages such as Doppler and delay resilience,reduced signaling latency,a lower peak-to-average ratio(PAPR),and a reduced-complexity implementation.Recent studies further indicate that the direct interplay between information and the physical world in the DD domain positions OTFS as a promising waveform for achieving integrated sensing and communications(ISAC).In this article,we present an in-depth review of OTFS technology in the context of the 6G era,encompassing fundamentals,recent advancements,and future directions.Our objective is to provide a helpful resource for researchers engaged in the field of OTFS.

Modelling and Performance Analysis of Visible Light Communication System in Industrial Implementations

Visible light communication(VLC)has a paramount role in industrial implementations,especially for better energy efficiency,high speed-data rates,and low susceptibility to interference.However,since studies on VLC for industrial implementations are in scarcity,areas concerning illumination optimisation and communication performances demand further investigation.As such,this paper presents a new modelling of light fixture distribution for a warehouse model to provide acceptable illumination and communication performances.The proposed model was evaluated based on various semi-angles at half power(SAAHP)and different height levels for several parameters,including received power,signal to noise ratio(SNR),and bit error rate(BER).The results revealed improvement in terms of received power and SNR with 30 Mbps data rate.Various modulations were studied to improve the link quality,whereby better average BER values of 5.55×10^(−15) and 1.06×10^(−10) had been achieved with 4 PAM and 8 PPM,respectively.The simulation outcomes are indeed viable for the practical warehouse model.

Optimizing Optical Attocells Positioning of Indoor Visible Light Communication System

Visible light communication(VLC),which is a prominent emerging solution that complements the radio frequency(RF)technology,exhibits the potential to meet the demands of fifth-generation(5G)and beyond technologies.The random movement of mobile terminals in the indoor environment is a challenge in the VLC system.The model of optical attocells has a critical role in the uniform distribution and the quality of communication links in terms of received power and signal-to-noise ratio(SNR).As such,the optical attocells positions were optimized in this study with a developed try and error(TE)algorithm.The optimized optical attocells were examined and compared with previous models.This novel approach had successfully increased minimum received power from−1.29 to−0.225 dBm,along with enhanced SNR performance by 2.06 dB.The bit error rate(BER)was reduced to 4.42×10−8 and 6.63×10−14 by utilizing OOK-NRZ and BPSK modulation techniques,respectively.The optimized attocells positions displayed better uniform distribution,as both received power and SNR performances improved by 0.45 and 0.026,respectively.As the results of the proposed model are optimal,it is suitable for standard office and room model applications.

Modeling Components and Services of LTE Mobile Communications System

The latest wireless broadband network standard is LTE (Long Term Evolution) which is developed by 3GPP (3rd Generation Partnership Project). It will enable mobile devices such as smart phones, tablets and laptops to access Internet at a very high speed along with lots of multimedia services. There are many issues that are yet to be solved due to dynamic complex nature of wireless systems, multimedia software applications and software requirements. Poor service quality, service disconnections due to mobility, seamless handover, handover interruption time and downward compatibility to other Radio Access Networks (RAN) are some of the key issues for the current LTE systems that are addressed very recently in the scientific literature. Formal method is one of the promising software engineering techniques that assure quality and perfection in software system models. Formal methods use mathematical language to explicitly specify system specifications and requirements that serve as initial grounds for further development and implementation. It efficiently handles all component connections and resource management parameters using discrete structures. Z Schema language is used to model static aspects of LTE communications system. All the schemas are being verified using Z/Eves toolset. The aim is to provide sound mathematical foundation for system validation and verification that eventually results in a more reliable, scalable and complete software system.

Observed communication between oncologists and patients:A causal model of communication competence

AIM: To investigate and test a causal model derived from previous meta-analytic data of health provider behaviors and patient satisfaction.METHODS: A literature search was conducted for relevant manuscripts that met the following criteria: Reported an analysis of provider-patient interaction in the context of an oncology interview; the study had to measure at least two of the variables of interest to the model(provider activity,provider patient-centered communication,provider facilitative communication,patient activity,patient involvement,and patient satisfaction or reduced anxiety); and the information had to be reported in a manner that permitted the calculation of a zero-order correlation between at least two of the variables under consideration.Data were transformed into correlation coefficients and compiled to produce the correlation matrix used for data analysis.The test of the causal model is a comparison of the expected correlation matrix generated using an Ordinary Least Squares method of estimation.The expected matrix iscompared to the actual matrix of zero order correlation coefficients.A model is considered a possible fit if the level of deviation is less than expected due to random sampling error as measured by a chi-square statistic.The significance of the path coefficients was tested using a z test.Lastly,the Sobel test provides a test of the level of mediation provided by a variable and provides an estimate of the level of mediation for each connection.Such a test is warranted in models with multiple paths.RESULTS: A test of the original model indicated a lack of fit with the summary data.The largest discrepancy in the model was between the patient satisfaction and the provider patient-centered utterances.The observed correlation was far larger than expected given a mediated relationship.The test of a modified model was undertaken to determine possible fit.The corrected model provides a fit to within tolerance as evaluated by the test statistic,χ2(8,average n = 342) = 10.22.Each of the path coefficients for the model reveals that each one can be considered significant,P < 0.05.The Sobel test examining the impact of the mediating variables demonstrated that patient involvement is a significant mediator in the model,Sobel statistic = 3.56,P < 0.05.Patient active was also demonstrated to be a significant mediator in the model,Sobel statistic = 4.21,P < 0.05.The statistics indicate that patient behavior mediates the relationship between provider behavior and patient satisfaction with the interaction.CONCLUSION: The results demonstrate empirical support for the importance of patient-centered care and satisfy the need for empirical casual support of provider-patient behaviors on health outcomes.

Embedded System Implementation of Airborne Communication Terminals

Airborne communication terminal is a key unit in Ad hoc network of aircrafts. This paper mainly focuses on its implementation by embedded system, which is based on Samsung S3C2410 chip. System architecture, Linux tailoring and touch-screen driver design are discussed in detail. Considering the requirements of stability and efficiency of the operating system, dynamic driver-loading method was employed firstly and only the necessary library files were transplanted to assist and test. The drivers finally were directly put into kernel configuration and then an integrated kernel was transplanted. Regarding to the problem of positioning issues on touch-screen, which is implemented in this system, an accurate positioning method is also presented.

The portrayal of hearing loss information in online Mandarin videos

Background/purpose:With increasing accessibility to the Internet,patients frequently use the Internet for hearing healthcare information.No study has examined the information about hearing loss available in the Mandarin language on online video-sharing platforms.The study’s primary purpose is to investigate the content,source,understandability,and actionability of hearing loss information in the Mandarin language’s one hundred most popular online videos.Method:In this project,publicly accessible online videos were analyzed.One hundred of the most popular Mandarin-language videos about hearing loss were identified(51 videos on YouTube and 49 on the Bilibili video-sharing platform).They were manually coded for different popularity metrics,sources,and content.Each video was also rated using the Patient Education Materials Assessment Tool for Audiovisual Materials(PEMAT-AV)to measure the understandability and actionability scores.Results:The video sources were classified as either media(n=36),professional(n=39),or consumer(n=25).The videos covered various topics,including symptoms,consequences,and treatment of hearing loss.Overall,videos attained adequate understandability scores(mean=73.6%)but low(mean=43.4%)actionability scores.Conclusions:While existing online content related to hearing loss is quite diverse and largely understandable,those videos provide limited actionable information.Hearing healthcare professionals,media,and content creators can help patients better understand their conditions and make educated hearing healthcare decisions by focusing on the actionability information in their online videos.

Joint optimization for secure ambient backscatter communication in NOMA-enabled IoT networks

Non-Orthogonal Multiple Access(NOMA)has emerged as a novel air interface technology for massive connectivity in Sixth-Generation(6G)era.The recent integration of NOMA in Backscatter Communication(BC)has triggered significant research interest due to its applications in low-powered Internet of Things(IoT)networks.However,the link security aspect of these networks has not been well investigated.This article provides a new optimization framework for improving the physical layer security of the NOMA ambient BC system.Our system model takes into account the simultaneous operation of NOMA IoT users and the Backscatter Node(BN)in the presence of multiple EavesDroppers(EDs).The EDs in the surrounding area can overhear the communication of Base Station(BS)and BN due to the wireless broadcast transmission.Thus,the chief aim is to enhance link security by optimizing the BN reflection coefficient and BS transmit power.To gauge the performance of the proposed scheme,we also present the suboptimal NOMA and conventional orthogonal multiple access as benchmark schemes.Monte Carlo simulation results demonstrate the superiority of the NOMA BC scheme over the pure NOMA scheme without the BC and conventional orthogonal multiple access schemes in terms of system secrecy rate.

31.38 Gb/s GaN-based LED array visible light communication system enhanced with V-pit and sidewall quantum well structure

Although the 5G wireless network has made significant advances,it is not enough to accommodate the rapidly rising requirement for broader bandwidth in post-5G and 6G eras.As a result,emerging technologies in higher frequencies including visible light communication(VLC),are becoming a hot topic.In particular,LED-based VLC is foreseen as a key enabler for achieving data rates at the Tb/s level in indoor scenarios using multi-color LED arrays with wavelength division multiplexing(WDM)technology.This paper proposes an optimized multi-color LED array chip for high-speed VLC systems.Its long-wavelength GaN-based LED units are remarkably enhanced by V-pit structure in their efficiency,especially in the“yellow gap”region,and it achieves significant improvement in data rate compared with earlier research.This work investigates the V-pit structure and tries to provide insight by introducing a new equivalent circuit model,which provides an explanation of the simulation and experiment results.In the final test using a laboratory communication system,the data rates of eight channels from short to long wavelength are 3.91 Gb/s,3.77 Gb/s,3.67 Gb/s,4.40 Gb/s,3.78 Gb/s,3.18 Gb/s,4.31 Gb/s,and 4.35 Gb/s(31.38 Gb/s in total),with advanced digital signal processing(DSP)techniques including digital equalization technique and bit-power loading discrete multitone(DMT)modulation format.

Reading Levels of Leaflets of Common Over-the-Counter Drugs in Ghana

Health communication is critical component of effective health delivery. While there are studies on the readability Patient Information Leaflets (PILs) around the world, so far, there is only one Ghanaian study that explored the language of patient information leaflets for malaria. The present study explores the language of PILs of seven common ailments in Ghana. In all, 68 leaflets were purposely sampled for the study. Using SMOG and Flesch Kincaid grade level readability formulae, the researcher measured the readability of PILs and discovered that the readability of all the PILs was difficult to read except the dewormer leaflets that scored standard reading score. Further statistical analysis reveal that the lexical and syntactic complexity of the leaflets were not statistically different. Finally, an interview with 20 patients confirmed that the leaflets are difficult to read due to the complex words and long sentence structures. It is recommended that the PILs be revised to make the leaflets readable.

Aspect-Level Sentiment Analysis Based on Deep Learning

In recent years,deep learning methods have developed rapidly and found application in many fields,including natural language processing.In the field of aspect-level sentiment analysis,deep learning methods can also greatly improve the performance of models.However,previous studies did not take into account the relationship between user feature extraction and contextual terms.To address this issue,we use data feature extraction and deep learning combined to develop an aspect-level sentiment analysis method.To be specific,we design user comment feature extraction(UCFE)to distill salient features from users’historical comments and transform them into representative user feature vectors.Then,the aspect-sentence graph convolutional neural network(ASGCN)is used to incorporate innovative techniques for calculating adjacency matrices;meanwhile,ASGCN emphasizes capturing nuanced semantics within relationships among aspect words and syntactic dependency types.Afterward,three embedding methods are devised to embed the user feature vector into the ASGCN model.The empirical validations verify the effectiveness of these models,consistently surpassing conventional benchmarks and reaffirming the indispensable role of deep learning in advancing sentiment analysis methodologies.

Muscle strength deficits are associated with low bone mineral density in young pediatric cancer survivors:The iBoneFIT project

Background Pediatric cancer survivors are at increased risk of muscle weakness and low areal bone mineral density(aBMD).However,the prevalence of muscle strength deficits is not well documented,and the associations of muscle strength with aBMD are unknown in this population.Therefore,this study aimed to investigate the prevalence of upper-and lower-body muscle strength deficits and to examine the associations of upper-and lower-body muscle strength with age-,sex,and race-specific aBMD Z-scores at the total body,total hip,femoral neck,and lumbar spine.Methods This cross-sectional study included 116 pediatric cancer survivors(12.1±3.3 years old,mean±SD;42.2%female).Upper-and lower-body muscle strength were assessed by handgrip and standing long jump test,respectively.Dual‑energy X‑ray absorptiometry was used to measure aBMD(g/cm2).Associations between muscle strength and aBMD were evaluated in multivariable linear regression models.Logistic regression was used to evaluate the contribution of muscle strength(1-decile lower)to the odds of having low aBMD(Z-score≤1.0).All analyses were adjusted for time from treatment completion,radiotherapy exposure,and body mass index.Results More than one-half of survivors were within the 2 lowest deciles for upper-(56.9%)and lower-body muscle strength(60.0%)in comparison to age-and sex-specific reference values.Muscle strength deficits were associated with lower aBMD Z-scores at all sites(B=0.133–0.258,p=0.001–0.032).Each 1-decile lower in upper-body muscle strength was associated with 30%–95%higher odds of having low aBMD Z-scores at all sites.Each 1-decile lower in lower-body muscle strength was associated with 35%–70%higher odds of having low aBMD Z-scores at total body,total hip,and femoral neck.Conclusion Muscle strength deficits are prevalent in young pediatric cancer survivors,and such deficits are associated with lower aBMD Z-scores at all sites.These results suggest that interventions designed to improve muscle strength in this vulnerable population may have the added benefit of improving aBMD.

A High-Speed Bi-Directional Visible Light Communication System Based on RGB-LED

In this paper,we propose and experimentally demonstrate a bi-directional indoor communication system based on visible light RGB-LED.Spectrally efficient modulation formats(QAM-OFDM),advanced digital signal processing,pre- and postequalization are adopted to compensate the severe frequency response of indoor channel.In this system,we utilize red-green-blue Light emitting diodes(LEDs),of which each color can be used to carry different signals.For downlink,the low frequencies of each color are used while for uplink,the high frequencies are used.The overall data rate of downlink and uplink are 1.15-Gb/s and 300-Mb/s.The bit error ratios(BERs) for all channels after0.7 m indoor delivery are below pre-forwarderror-correction(pre-FEC) threshold of3.8×l0^(-3) To the best of our knowledge,this is the highest data rate in bi-directional visible light communication system.

Mission-Oriented Configuration Model of Aircraft Carrying Spares and Dynamic Optimization Policy

Spare parts are critical to scheduled maintenance and fault repair,and can directly affect the readiness and combat capability of equipment.Equipment′s capacity of carrying spares is influenced by its storage space and scales,so it is necessary to consider economic factors,e.g.spares cost,as well as non-economic ones,such as spares volume,mass and scale,when optimizing spares configuration.Aiming at this problem,the optimization model based on multi-constraints for carrying spares is built by METRIC theory and system analysis.Through the introduction of Lagrange factors,the spares cost is transformed to shadow price,and the optimization method for carrying spares and the dynamic adjustment policy of Lagrange factors are proposed.The result of a given example is analyzed,and demonstrates that the proposed model can be optimized with all constraints,and the research can provide a new way for carrying spares optimization.

Multiparty Quantum Secret Sharing of Quantum States with Quantum Registers

分享计划的一个量秘密被使用 quantumregisters 建议。在建议计划，秘密消息状态被编码进多国参加的 entangledstates。几个相同多粒子纠纷状态被产生， theentanglement 状态的每个粒子被填充当 secretmessage 的份额的不同的量寄存器。二个模式，即检测模式和消息模式，被采用以便 theeavesdropping 能容易被检测，秘密消息可以被恢复。建议计划对偷听者偷听并且欺骗 ofparticipants 是安全的安全 analysisshows。

Impacts of Packet Collisions on Link Throughput in CSMA Wireless Networks

It is known that packet collisions in wireless networks will deteriorate system performance, hence substantial efforts have been made to avoid collision in multi-user access designs. Also, there have been many studies on throughput analysis of CSMA wireless networks. However, for a typical CSMA network in which not all nodes can sense each other, it is still not well investigated how link throughputs are affected by collisions. We note that in practical 802.11-like networks, the time is divided into mini-timeslots and packet collisions are in fact unavoidable. Thus, it is desirable to move forward to explore how collisions in such a network will affect system performance. Based on the collision-free ideal CSMA network(ICN) model, this paper attempts to analyze link throughputs when taking the backoff collisions into account and examine the effect of collisions on link throughputs. Specifically, we propose an Extended Ideal CSMA Network(EICN) model to characterize the collision effects as well as the interactions and dependency among links in the network. Based on EICN, we could directly compute link throughputs and collision probabilities. Simulations show that the EICN model is of high accuracy. Under various network topologies and protocol parameter settings, the computation error of link throughputs using EICN is kept to 4% or below. Interestingly, we find that unlike expected, the effect of collisions on link throughputs in a modest CSMA wireless network is not significant, which enriches our understanding on practical CSMA wireless networks such as Wi-Fi.

Multicast Capacity of Cache Enabled Content-Centric Wireless Ad Hoc Networks

In this paper, we investigate the upper bound of multicast capacity for content-centric wireless ad hoc networks with content-centric hierarchical routing strategy. We consider two content-centric hierarchical routing strategies, namely, the homogeneous hierarchical routing strategy where each content is requested and cached with equal probability, and the heterogenous hierarchical routing strategy where each content is cached with different probabilities and the requested contents follow a Zipf content popularity distribution. For the two proposed hierarchical routing strategies, we establish the upper bounds on multicast capacity of content-centric wireless ad hoc networks, respectively. We then discuss how the system parameters, such as the number of nodes n, the number of users p, the cache size C, the probability of cache and the content popularity distribution impact on the muilticast capacity scalings.

A Novel Deterministic Quantum Communication Scheme Using Stabilizer Quantum Code

利用 stabilizer 量代码的编码进程[[n， k， d ]] ，一个确定的量通讯计划，在哪个 n - 1 个光子在双向隧道向前并且向后被散布，被建议与无条件的安全播送秘密消息。现在的计划能被实现散布秘密的量(或古典) 自从利用代码为每计划跑编码 k-qubit 消息，在有瑕疵的量隧道与大能力发送消息。