Highlights • ECS is a major prognostic factor in HNSCC. • No standardized histological diagnostic and grading criteria are available for ECS. • There is a correlation between the level of extension ...of ECS and a poor prognosis. • Cisplatin-based chemo-radiotherapy is the recommended treatment for ECS. • ECS is not an adverse prognostic factor in HPV-positive OPSCC.
•Two spread models are proposed from the deterministic and random aspects based on the substitution dynamic system and the theory of branching processes.•The long-term behaviors of the spread rates ...are found in both deterministic and random models.•The transition of two spread patterns during the pandemic period can be described.•Our methodology provides a way to compare two spread patterns which can be used as a reference for decision making.
This paper models the spread of the pandemic with mathematical analysis to provide predictions for different classes of individuals. We consider the spread by using a branching process and a substitution dynamical system as random and deterministic models, respectively, to approximate the pandemic outbreak. Both approaches are based on the assumption of Markov processing. The deterministic model provides an explicit estimate for the proportion of individuals of a certain type in the particular generation given any initial condition, where a generation means a unit of observation time. The proportion relates to the matrix derived from the Markov setting. In addition, the methodology reveals the efficiency of epidemic control policies, such as vaccine injections or quarantine, by the relative spread rate that is used for the prediction of the number of individuals of a certain type. On the other hand, the stochastic approximation has more of an empirical impact than the deterministic one does. Our investigation explicitly exhibits the spread rate of a certain type with respect to an initial condition of any type. After estimating the average spread rate, the effect of adopting a particular policy can be evaluated. The novelty of this elucidation lies in connecting these two models and introducing the idea of the transition spread model between two topological spread models to capture the change of the spread patterns, which is a real-world phenomenon during the epidemic periods due to changes in the environment or changes in disease control policies. Roughly speaking, the deterministic model is a special case of the stochastic model under some particular probability. Most importantly, with the help of the stochastic model, we establish the transition processing of two deterministic models, which is called a transition model. In other words, any stochastic model is “bounded” by two deterministic models. Moreover, a computable way has been established to predict the long-term spread rate due to the Markov properties of the models and matrix representations for the spread patterns.
This paper provides a comprehensive performance comparison between a current robust military waveform; namely, MIL-STD-188-110D, Waveform 0, and a filter bank multicarrier spread-spectrum (FBMC-SS) ...waveform proposed for communications through ionospheric/skywave HF channels. Waveform 0 is effectively a direct sequence spread spectrum waveform that uses Walsh multi-codes to enhance the information transmission rate. It may thus be referred to as Walsh-DSSS. FBMC-SS, on the other hand, makes use of filter banks to provide excellent performance when the received signal is subject to partial band interference. Successful application of FBMC-SS for communications across skywave HF channels has been previously demonstrated, both theoretically and through experimental work. However, very little has been done to contrast FBMC-SS against Walsh-DSSS. The goal of this paper is to first add new features to FBMC-SS to bring it on par with Walsh-DSSS. These features include: (i), introduction of multi-codes that achieve a comparable (or better) data rate to Walsh-DSSS; and (ii), addition of a scrambling step applied to the multi-codes to make the receiver detection robust against widely spread multipaths. With this established, in the second part of the paper, we examine the performance of the developed FBMC-SS against Walsh-DSSS when both are applied for communications across skywave HF channels. The two waveforms are compared both through a theoretical study and through experimental works across several skywave channels ranging from hundreds to thousands of kilometers.
Pine wilt disease (PWD) is the most destructive forest disease in Far East Asia and is a major concern in South Korea, China, Taiwan, and Japan. This disease naturally spreads to nearby areas via ...insect vectors, whereas anthropogenic spread occurs randomly and transfers the disease far away. However, few studies have analyzed the spread patterns and distances of PWD to establish effective monitoring strategies. Accordingly, the aim of this study was to determine the boundary distance distinguishing natural and anthropogenic spread using a regression analysis of monitoring records for a six-year period from South Korea. In addition, we developed a MaxEnt model using both climatic and anthropogenic factors to predict the potential distribution of PWD. The results showed that the average distance of the natural spread from 2017 to 2021 was approximately 13.8 km, while the model identified that seasonal climatic conditions exacerbated PWD spread. Consequently, a control strategy to prevent the spread of PWD should be effectively designed based on climate and boundary distance.
•The annual spread distance of pine wilt disease (PWD) was analyzed.•Average temperature and total precipitation were correlated with spread of PWD.•The spread distance of PWD was accurately fitted by a nonlinear equation.•An average natural spread distance of PWD was 13.8 km.•The MaxEnt with climatic factors (non-climatic factors) showed AUC of 0.731 (0.62).
Switched mode power supplies (SMPSs) are essential components in many applications, and electromagnetic interference is an important consideration in the SMPS design. Spread spectrum-based pulse ...width modulation (PWM) strategies have been used in SMPS designs to reduce the switching harmonics. This paper proposes a novel method to integrate a communication function into spread spectrum-based PWM strategy without extra hardware costs. Direct sequence spread spectrum (DSSS) and phase shift keying data modulation are employed to the PWM of the SMPS, so that it has reduced switching harmonics and the input and output power line voltage ripples contain data. A data demodulation algorithm has been developed for receivers, and code division multiple access (CDMA) concept is employed as a communication method for a system with multiple SMPSs. The proposed method has been implemented in both Buck and Boost converters. The experimental results validated the proposed DSSS-based PWM strategy for both harmonic reduction and communication.
Reactive jammers have been shown to be a serious threat for wireless communication. Despite this, it is difficult to detect their presence reliably. We propose a novel method to detect such ...sophisticated jammers in direct sequence spread spectrum (DSSS) wireless communication systems. The key idea is to extract statistics from the jamming-free symbols of the DSSS synchronizer to discern jammed packets from those lost due to bad channel conditions. Our contribution is twofold. First, we experimentally evaluate new empirical models utilizing the preamble symbols of IEEE 802.15.4 packets, thus enabling the accurate prediction of the packet delivery ratio (PDR). We show that the chip error rate-based metric is superior to metrics used in the literature, offering an accurate and reactive indicator of the true PDR. Our second contribution is the design and evaluation of a detection technique relying on this metric to detect reactive jammers. We build a software-defined radio testbed and show that our technique enables the error-free detection of reactive jammers that jam all packets on links with a PDR above 0.3. To the best of our knowledge, our detector is the first to detect reactive jamming attacks targeting the physical layer header of DSSS packets, and does not require any modifications of the wireless communication system.
An extensive review of the statistical characterization of 60-GHz indoor radio channels is provided from a large number of published measurement and modeling results. First, the most prominent driver ...applications for 60 GHz are considered in order to identify those environment types that need to be characterized most urgently. Large-scale fading is addressed yielding path-loss parameter values for a generic 60-GHz indoor channel model as well as for the office environment in particular. In addition, the small-scale channel behavior is reviewed including the modeling of time-of-arrival and angle-of-arrival details and statistical parameters related to delay spread, angular spread and Doppler spread. Finally, some research directions for future channel characterization are given.
Fascioliasis is a plant- and waterborne zoonotic parasitic disease caused by two trematode species: (i) Fasciola hepatica in Europe, Asia, Africa, the Americas, and Oceania and (ii)
, which is ...restricted to Africa and Asia. Fasciolid liver flukes infect mainly herbivores as ruminants, equids, and camelids but also omnivore mammals as humans and swine and are transmitted by freshwater Lymnaeidae snail vectors. Two phases may be distinguished in fasciolid evolution. The long predomestication period includes the
origin in east-southern Africa around the mid-Miocene, the
origin in the Near-Middle East of Asia around the latest Miocene to Early Pliocene, and their subsequent local spread. The short postdomestication period includes the worldwide spread by human-guided movements of animals in the last 12,000 years and the more recent transoceanic anthropogenic introductions of
into the Americas and Oceania and of
into several large islands of the Pacific with ships transporting livestock in the last 500 years. The routes and chronology of the spreading waves followed by both fasciolids into the five continents are redefined on the basis of recently generated knowledge of human-guided movements of domesticated hosts. No local, zonal, or regional situation showing disagreement with historical records was found, although in a few world zones the available knowledge is still insufficient. The anthropogenically accelerated evolution of fasciolids allows us to call them "peridomestic endoparasites." The multidisciplinary implications for crucial aspects of the disease should therefore lead the present baseline update to be taken into account in future research studies.
The energy of a simple graph G is defined as the sum of the absolute values of eigenvalues of the adjacency matrix of G. For a complex matrix M the spread of M is the maximum absolute value of the ...differences between any two eigenvalues of M. Thus if λ1,…,λn are the eigenvalues of M, then the spread of M is max1≤i,j≤n|λi−λj|. The spread of a graph G is defined as the spread of its adjacency matrix and is denoted by s(G). The inertia of G is an integer triple (n+,n−,n0) specifying the numbers of positive, negative and zero eigenvalues of the adjacency matrix of G. In this paper we find some bounds for energy of graphs in terms of some parameters of graphs such as rank, inertia and spread of graphs. We find some bounds for spread of graphs and matrices that improve the previous bounds. In particular, we show that if G is a graph with m edges and inertia (n+,n−,n0), then s(G)≥2m(n++n−)n+n− and the equality holds if and only if G=rKs∪tK1 or G=rKp,…,p︸q∪tK1 or G=r1Ka1,b1∪⋯∪rhKah,bh, for some non-negative integers r,s,t,p,q and r1,a1,b1,…,rh,ah,bh such that a1b1=⋯=ahbh, p≥2 and q≥3.
To understand the roles of different transport modes in the spread of COVID-19 pandemic across Chinese cities, this paper looks at the factors influencing the number of imported cases from Wuhan and ...the spread speed and pattern of the pandemic. We find that frequencies of air flights and high-speed train (HST) services out of Wuhan are significantly associated with the number of COVID-19 cases in the destination cities. The presence of an airport or HST station at a city is significantly related to the speed of the pandemic spread, but its link with the total number of confirmed cases is weak. The farther the distance from Wuhan, the lower number of cases in a city and the slower the dissemination of the pandemic. The longitude and latitude coordinates do not have a significant relationship with the number of total cases but can increase the speed of the COVID-19 spread. Specifically, cities in the higher longitudinal region tended to record a COVID-19 case earlier than their counterparties in the west. Cities in the north were more likely to report the first case later than those in the south. The pandemic may emerge in large cities earlier than in small cities as GDP is a factor positively associated with the spread speed.
•This paper explores the factors influencing the COVID-19 spread speed and spatial pattern.•Frequencies of flights and HSTs are significantly associated with the number of cases.•The farther the distance from Wuhan, the lower the number of cases and dissemination speed.
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