Actual Transmission Rate Research Articles

Information Transmission via Molecular Communication in Astrobiological Environments.

The ubiquity of information transmission via molecular communication between cells is comprehensively documented on Earth; this phenomenon might even have played a vital role in the origin(s) and early evolution of life. Motivated by these considerations, a simple model for molecular communication entailing the diffusion of signaling molecules from transmitter to receiver is elucidated. The channel capacity C (maximal rate of information transmission) and an optimistic heuristic estimate of the actual information transmission rate are derived for this communication system; the two quantities, especially the latter, are demonstrated to be broadly consistent with laboratory experiments and more sophisticated theoretical models. The channel capacity exhibits a potentially weak dependence on environmental parameters, whereas the actual information transmission rate may scale with the intercellular distance d as ∝ d-4 and could vary substantially across settings. These two variables are roughly calculated for diverse astrobiological environments, ranging from Earth's upper oceans (C ∼ 3.1 × 103 bits/s; ∼ 4.7 × 10-2 bits/s) and deep sea hydrothermal vents (C ∼ 4.2 × 103 bits/s; ∼ 1.2 × 10-1 bits/s) to the hydrocarbon lakes and seas of Titan (C ∼ 3.8 × 103 bits/s; ∼ 2.6 × 10-1 bits/s).

Power and rate control in wireless communication systems with energy harvesting and rateless codes

In this paper, for a wireless communication system with energy harvesting and rateless error correction codes, the joint optimization of transmit power, modulation scheme and code rate to maximize the long-term average achievable transmission rate under the constraint of available energy is studied. The method is given first to determine the codeword length (or code rate) for a signal-to-noise ratio (SNR) under the constraint of a pre-defined decoding error probability. Then the formula of the actual transmission rate is deduced with a specific modulation and code rate, and the optimization problem to maximize the long-term average actual transmission rate is constructed under the constraints of available harvested energy and the decoding complexity of the rateless code. Since energy harvesting and channel fading are both stochastic processes, the optimization problem is difficult to solve. By using the Lyapunov optimization framework, the original long-term optimization problem is transformed into a per time slot one. Then an efficient numerical method is proposed to obtain the solution to the problem. The proposed algorithm is verified by simulation, and the results show that the proposed algorithm can achieve a higher average actual transmission rate than the comparison algorithms aiming at optimizing the channel capacity.

Epidemics on multilayer simplicial complexes

Simplicial complexes describe the simple fact that in social networks a link can connect more than two individuals. As we show here, this has far-reaching consequences for epidemic spreading, in particular in the context of a multilayer network model, where one layer is a virtual social network and the other one is a physical contact network. The social network layer is responsible for the transmission of information via pairwise or higher order 2-simplex interactions among individuals, while the physical layer is responsible for the epidemic spreading. We use the microscopic Markov chain approach to derive the probability transition equations and to determine epidemic outbreak thresholds. We further support these results with Monte Carlo simulations, which are in good agreement, thus confirming the analytical tractability of the proposed model. We find that information transmission rates are frequently low when actual disease transmission rates in the physical network are low or medium, and we show that this can be mitigated effectively by introducing 2-simplex interactions in the social network. The relative ease of introducing higher-order interactions in virtual social networks means that this could be exploited to inhibit epidemic outbreaks.

Average Achievable Rate and Average BLER Analyses for MIMO Short-Packet Communication Systems

Multiple-input-multiple-output (MIMO) systems significantly increase the network throughput and coverage probability for short-packet communications. In this paper, a tight lower bound on the average achievable rate of MIMO short-packet communication systems is theoretically derived, considering flat uncorrelated Rayleigh fading MIMO channels. The derivations are based on the eigenvalue analysis of a Wishart matrix and Jensen's inequality. Given the actual transmission rate, a tight approximation on the average block error rate (BLER) of MIMO short-packet communication systems is also provided, which is based on the moment generating function and inverse Laplace transform. Numerical results demonstrate that both our theoretically derived analytical average achievable rate lower bound and approximate average BLER are almost the same as the simulation results.

Performance modeling of multipath mobile data offloading in cellular/WiFi networks with bandwidth uncertainty

Mobile data offloading is one of the most effective approaches for improving the Quality of Service (QoS) of mobile users. Through this method, the mobile data traffic load over a cellular network is mitigated by offloading some of the traffic to an alternative path; usually a WiFi network. Most previous studies on WiFi offloading have assumed that the data traffic is offloaded to a path with constant bandwidth. However, in real-world applications, it is generally impossible to perform data transmission at a constant rate through WiFi over the entire offloading process, Hence, one of the most challenging issues in analyzing the performance of mobile data offloading is that of evaluating the effects of bandwidth uncertainty on the actual transmission rate. Accordingly, the present study proposes an analytical model for predicting the performance of multipath data offloading over WiFi network with bandwidth uncertainty. The theoretical results are validated by means of numerical simulations. The effectiveness of the proposed model is then further investigated by comparing the QoS metrics of the data offloading process with those obtained in a previous study on mobile data offloading under the assumption of a constant bandwidth. Overall, as the WiFi connection times are highly larger than the WiFi disconnection times, our model removes estimated errors in the baseline model by 8.7% and 6.7% in deadline miss ratio, by 23.2% and 14.9% in average offloading volume, when we consider two and three varying WiFi bandwidth respectively. The results show that the proposed method provides mobile operators with an effective framework for maintaining the QoS level of mobile data offloading in real-world networks characterized by WiFi bandwidth uncertainty.

Performance Research of LoRa at High Transmission Rate

In recent years, most of Lora’s research in the field of wireless technology has focused on the experimental exploration of its stability and communication range, without much attention to the impact of the actual transmission rate. However, as the length of Lora transmission load increases, the growth rate of low-speed transmission time is faster than that of high-speed transmission time. Therefore, it means that for the transmission of large capacity packets, the lower the transmission rate, the more time it takes; the longer the time, the more power it consumes. In this paper, the SNR, RSSI and packet loss rate of Lora over 3 Kbps in urban area and mountainous area were tested and explored respectively, and the RSSI curve with distance in different environment was obtained. The test results show that the actual communication distance of Lora with high transmission rate of 21875 bps in line of sight environment can reach 3 Km, packet loss rate is less than 1%. In addition, the influence of Lora on communication quality under different occlusion degrees in a certain range was tested. In the range of 500 m to 3 km, when the occlusion ratio was 0-5%, the highest speed reference value was 21875 bps, 5-10% reference value was 6250 bps, and more than 10% reference value was 3125 bps. In this paper, Lora SX1278 transceiver was used, in the same transmission of 100 KB data, the actual transmission rate is further improved by using the maximum duty cycle and improving the request response mechanism. Compared with a Lora system for image transmission, the transmission time is reduced by 81.3% and the transmission speed is increased by 4.3 times, which greatly improves the transmission efficiency of large capacity data such as image.

Quantitative evaluation on control measures for an epidemic: A case study of COVID-19

<p indent="0mm">The spread of an epidemic should be a phenomenon governed by the natural growth law: More infected beget more infections. This basic rule would be useful especially when an outbreak is caused by a novel virus with its basic characteristics full of unknowns so much that there would be too many uncertainties that would be impossible for anyone to run the traditional epidemiological model meaningfully. The natural growth law does not depend on the detailed characteristics of the virus. When it is employed, a transmission rate can be defined and determined directly from clinical field data, which can change following the course of the epidemic development. Such a data driven natural growth model has been developed to track the development for any epidemic. It can yield useful information on the propagation pattern of the epidemic dynamically. The transmission rate so determined is sensitive enough not only to track the course of the epidemic but also to reveal the effects of control measures quantitatively. Importantly, it offers the potential to make predictions for epidemic management. In December 2019, a severe epidemic, the novel coronavirus epidemic, now designated as the COVID-19, broke out in Wuhan, China. It spread quickly in and around Wuhan. To complicate the situation, the outbreak initial period also coincided with the travel peak related with the Spring Festival. To prevent its spreading, Chinese government has instituted strict quarantine by lockdown the City and the surrounding Hubei Province. This drastic quarantine measure seemed to have slowed down the spread of the COVID-19 markedly. However, to evaluate the control effects quantitatively remains a challenge. In this paper, we propose to quantify the effectiveness of the quarantine using the natural growth model. Based on the model, we first estimated the transmission rates of the COVID-19 for different typical periods as follows: In December 2019, the transmission rate is about 0.26; in the late January 2020, it is between 0.40 and 0.46. Therefore, if the strict quarantine measures had not been instituted for the epidemic at all, 16.98 million to 76.11 million people would have been infected under the transmission rate between 0.40 and 0.46, as of February 18, 2020, according to the model. Even for a very low transmission rate as 0.26, there would have been 513 thousand infected as of February 18, 2020, far greater than the actual data of some 58 thousand reported by the Chinese National Health Commission. The model can also be used to estimate the consequence of putting off the control measures. We conducted a hypothetical study as follows. We divided the development of the epidemic into three stages: Before January 24, 2020, the infection grew as the actual situation does; from January 25, 2020 to the day before the supposed date of the start of the control measures, the infection grew with a transmission rate of 0.45; from the supposed date of the start of the control measure onwards, the infection took the actual transmission rate starting from January 25 on. Our model results indicate that the more days delayed for the quarantine measures, the faster increase of the infections. If the strict control measures were pushed back by one day (or 7 days), there would be 27 (or 785) thousand more infected cases than the reported as of February 18, 2020 in the whole China, in which 12 (or 493) thousand are in the Hubei Province. The above estimation is quite conservative. Less infected is easier to control; therefore, putting the measure control off we will have even more infected than estimated that would made the epidemic even harder to contain.

Calculation of equivalent friction coefficient for castor seed by single screw press

Based on the traction angle and transportation rate equation, castor beans were pressed by application of single screw under different cake diameter and different screw speed. The results showed that the greater the cake diameter and screw rotation speed, the greater the actual transmission rate was. The equivalent friction coefficient was defined and calculated as 0.4136, and the friction coefficients between press material and screw, bar cage were less than the equivalent friction coefficient value.

Bandwidth analysis of IEEE 802.11AC protocol on ARM platforms: Potential influencing factors

This paper measures the actual bandwidth of wireless devices on ARM platforms supporting the IEEE 802.11ac standard as the data transmission protocol under the condition that there is no occlusion in the transmission path. The influences of the transmission distance, the data transmission duration, and the driving devices on the transmission terminal on the data transmission rate are investigated in several experiments. The results indicate that the maximum bandwidth can reach 251.63 Mbps when ARM platforms are used on the transmission terminal and the transmission distance and duration do not influence the data transmission rate significantly (p-values are 0.3 and 0.07, respectively). We conclude that the actual data transmission rate of devices supporting the IEEE 802.11ac protocol may not reach the nominal level (~ 1Gbps), and the actual data transmission rate depends on the hardware configuration and other set up parameters.

Clinical implication of occult hepatitis B infection

Occult hepatitis B infection (OBI) can be found in three different clinical groups of patients according to the documentation of the history of hepatitis B virus (HBV) exposure. They are patients with definite history of apparently self-limiting acute hepatitis B infection, patients with known chronic hepatitis B (CHB) infection with loss of hepatitis B surface antigen (HBsAg) (HBsAg seroclearance) and patients without prior history of hepatitis B infection. The second group likely contributes the largest group of patient population in OBI. These patients have same rate of development of end-staged liver disease including cirrhosis-related complications and hepatocellular carcinoma (HCC) if HBsAg seroclearance occurs when there is pre-existing cirrhosis or at the age older than 50 years. Nevertheless, majority of the patients with OBI usually have normal liver biochemistry and histology. The intrahepatic HBV DNA is detectable in almost all the patients whereas the covalently closed circular (ccc)DNA and pre-genomic RNA levels are usually very low. With regard to the clinical implications, HBV transmission from the blood products of occult hepatitis B donors is possible as demonstrated in animal and human experiments, although the actual HBV transmission rate in human is quite low especially in anti-HBs positive recipients. HBV can also be transmitted to the recipients through organ transplantation especially liver transplantation from occult hepatitis B donors. OBI may be an accelerating risk factor for development of HCC in patients with chronic hepatitis C infection and patients with alcoholic liver disease. Importantly, OBI may also contribute to a great extent in patients with cryptogenic cause of HCC. In another scenario, patients with OBI may have severe hepatitis B reactivation with a surge of viral replication and hence clinical hepatitis and mortality. This phenomenon is more commonly seen in patients receiving immunosuppressive therapy especially anti-CD monoclonal antibody. Patients receiving haematopoetic stem cell transplantation also carry a high risk of hepatitis B reactivation. Prompt antiviral therapy at the time of detectable HBV DNA upon interval monitoring is very effective in controlling hepatitis B viral replication and therefore is associated with a hepatitis-free recovery.

Outcomes of kidney transplants and risk of infection transmission from increased infectious risk donors.

Concern over transmission of viral infections has been reported to result in higher discard rates of high infectious risk kidneys (HIR) although data on actual viral transmission rates are lacking. At our center, we performed 89 HIR and 533 non-HIR kidney transplants (KTs) between 2004 and 2011. Follow-up screening labs in recipients of HIR kidneys tested for human immunodeficiency virus, hepatitis C virus, and hepatitis B virus did not reveal any cases of viral transmission over median follow-up of 4.3years. Patient and graft outcomes were similar at 5years between HIR and non-HIR KTs. An updated analysis of the Organ Procurement and Transplant Network (OPTN) registry of deceased-donor kidney transplants between 2008 and 2012 included 57526 transplants was performed. Retrospective calculation of KDRI (kidney donor risk index) differed (P<.001) between all groups with median KDRI of 0.99 for HIR kidneys, 1.07 for non-HIR standard criteria donor kidneys, and 1.81 for non-HIR expanded criteria donor (ECD) kidneys. This was reflected in the significantly improved 5-year graft survival for HIR KTs when compared with non-HIR ECD KTs (84% vs 78%; P<.001). Our data can guide counseling of KT candidates about the safety and benefits of HIR kidneys.

Nearly-optimal scheduling of users with Markovian time-varying transmission rates

We address the problem of developing a well-performing and implementable scheduler of users with wireless connections to the central controller, which arise in areas such as mobile data networks, heterogeneous networks, or vehicular communications systems. The main feature of such systems is that the quality of each user’s channel is time-varying due to fading. The evolution of the channel over its quality states thus causes a time-varying transmission rate of each user. We consider Markovian channel dynamics, relaxing the common but unrealistic assumption of i.i.d. channels. We first focus on three-state channels and show that threshold policies (of giving higher priority to users with higher transmission rate) are not necessarily optimal. For the general case we design a scheduler which generalizes the recently proposed Potential Improvement (PI) scheduler, which gives priority to the users who are unlikely to improve their actual transmission rate soon by much. We propose two practical approximations of PI, whose performance is analyzed and compared to existing alternative schedulers in a variety of simulation scenarios. Our computational experiments indicate that the variant of PI, which only relies on the steady-state distribution of the channel, is robust and performs extremely well, and therefore we recommend its use for practical implementation.

A New Method of Real-Time Detecting the Chlorophyll Based on Hover Wing UAV

A fluorescent real-time detection technology parameters of the chlorophyll radiation LED method using with fluorescent MINIPAM based on impulse, modulation, is introduced. The using of programming power to provide a constant flow of the list of output, LED by a matrix as chlorophyll are fluorescent light. The using of apparatus in plant MINIPAM fluorescent light system II of the steady state Fs, a fluorescent light to the next largest fluorescent Fm',a combination of the environment, and tracking control system of measurement and comprehensive analysis of environmental factors to the real quantum efficiency, actual electronic transmission rate for parameters. MINIPAM fluorescent apparatus with the upper machine, and can be real time monitoring.

Methicillin Resistant Staphylococcus aureus Transmission in the Inpatient Psychiatric Hospital Setting

Surveillance data and the Infection Risk Assessment indicate incidence of Methicillin Resistant Staphylococcus aureus (MRSA) occurrence exceeds incidence of other multi drug resistant organisms (MDRO) in our hospital posing the highest risk for infection. The primary objective of the study: to identify the actual MRSA transmission rate on the patient care unit with the highest known pressure for transmission.

The intriguing complexity of parthenogenesis inheritance in Pilosella rubra (Asteraceae, Lactuceae)

Neither the genetic basis nor the inheritance of apomixis is fully understood in plants. The present study is focused on the inheritance of parthenogenesis, one of the basic elements of apomixis, in Pilosella (Asteraceae). A complex pattern of inheritance was recorded in the segregating F(1) progeny recovered from reciprocal crosses between the facultatively apomictic hexaploid P. rubra and the sexual tetraploid P. officinarum. Although both female and male reduced gametes of P. rubra transmitted parthenogenesis at the same rate in the reciprocal crosses, the resulting segregating F(1) progeny inherited parthenogenesis at different rates. The actual transmission rates of parthenogenesis were significantly correlated with the mode of origin of the respective F(1) progeny class. The inheritance of parthenogenesis was significantly reduced in F(1) n + n hybrid progeny from the cross where parthenogenesis was transmitted by female gametes. In F(1) n + 0 polyhaploid progeny from the same cross, however, the transmission rate of parthenogenesis was high; all fertile polyhaploids were parthenogenetic. It appeared that reduced female gametes transmitting parthenogenesis preferentially developed parthenogenetically and only rarely were fertilized in P. rubra. The fact that the determinant for parthenogenesis acts gametophytically in Pilosella and the precocious embryogenesis in parthenogenesis-transmitting megagametophytes was suggested as the most probable explanations for this observation. Furthermore, we observed the different expression of complete apomixis in the non-segregating F(1) 2n + n hybrids as compared to their apomictic maternal parent P. rubra. We suggest that this difference is a result of unspecified interactions between the parental genomes.

Traffic management in wireless sensor networks: Decoupling congestion control and fairness

In this paper, we propose a distributed congestion control algorithm for tree based communications in wireless sensor networks, that seeks to adaptively assign a fair and efficient transmission rate to each node. In our algorithm, each node monitors its aggregate output and input traffic rate. Based on the difference of the two, a node then decides to increase (if the output rate is more) or decrease (if the input rate is more) the bandwidth allocable to a flow originating from itself and to those being routed through it. Since the application requirements in sensor network follow no common trait, our design abstracts the notion of fairness, allowing for the development of a generic utility controlling module. Such separation of the utility and fairness controlling modules enable each one to use a separate control law, thereby portraying a more flexible design. The working of our congestion control is independent of the underlying routing algorithm and is designed to adapt to changes in the underlying routing topology. We evaluate the performance of the algorithm via extensive simulations using an event-driven packet level simulator. The results suggest that the proposed protocol acquires a significantly high goodput of around 95% of the actual transmission rate, converges quickly to the optimal rate, and attains the desired fairness.

A study of on/off timing channel based on packet delay distribution

An on/off timing channel is a typical network covert timing channel, which can be used by attackers to steal information from compromised systems without triggering network firewalls and intrusion detection systems. In this paper, we discuss the principle of the information transmission in an on/off timing channel and categorize such channels into two types: deterministic channels and non-deterministic channels. We then analyze the components of packet delay and their characteristics, and provide a method of calculating the maximum transmission rate of a non-deterministic channel based on the packet delay distribution. After that, we conduct experiments to obtain the packet delay distribution in real network, and calculate the maximum transmission rate via our method. Then we construct an actual channel, and attain the actual transmission rate based on the observed symbol transmission probabilities. Our experiments show that the transmission rate calculated through our method is close to the real one, and can reveal the risk of the information leakage via on/off time channels in a network. In addition, the results indicate that non-deterministic channels may bring more threat than deterministic ones in the same network, and the information leakage via on/off timing channels should gain more intention.

How Good Is the Tuberculin Skin Test?

Purified protein derivative is a relatively crude material containing several different antigens. The results of a skin test with purified protein derivative are dependent on the immunologic reactivity of the recipient of the test, and the final interpretation is dependent on the individual interpreting the test. Despite these limitations, the tuberculin skin test (TST) is one of the most accurate medical tests available. Using conservative assumptions, I have estimated the sensitivity of the TST at approximately 95% and the specificity at approximately 99% to 99.5%.2 If these assumptions are correct, the TST is more accurate than most tests commonly used in clinical medicine. Despite this high degree of accuracy, the TST is not good enough to give valid results in serial skin testing programs in most hospitals and other medical facilities where the prevalence of new infection is low (including facilities ordinarily considered to be at “moderately high risk”). The table translates the conversion rate in a serial skin testing program to the actual transmission rate of tuberculosis infection assuming a sensitivity of 0.95 and a specificity of 0.99 to 0.995. If the annual conversion rate in a skin testing program is less than 1%, most conversions will be false positives and the predictive value of an individual conversion will be poor. Conversion rates above 2% increase the predictive value of the test to greater than 50%, and results in skin testing programs with annual conversions of greater that 2% probably represent mostly true transmission of tuberculous infection. Conversion rates between 1% and 2% probably represent equal numbers of false-positive and true-positive tuberculin reactions. This issue of Infection Control and Hospital Epidemiology presents four reports concerning the TST.3-6 These reports are welcome, as the results of most serial skin testing programs in medical environments go unreported. Cook et al.4 report TST results among healthcare workers in New York City. The conversion rate in their study was approximately 1.3% annually—a rate that suggests equal numbers of true-positive and false-positive conversions. The presence of some true-positive conversions is supported by the increased conversion rate in high-risk settings and among foreign-born individuals, who would be expected to have a higher than average risk in their community away from the workplace. Some of the increased conversion rate among high-risk workers was probably the result of semiannual testing in this group compared with annual testing for low-risk workers, as more frequent testing will increase the cumulative false-positive rate if such a rate is constant for each test.2 Garber et al.3 report results of skin testing programs in 19 microbiology laboratories in New York City. The incidence of TST conversion in their study of 1% probably slightly favors false conversions over true conversions,

Throughput analysis of buffered continuous ARQ scheme with multiple copy retransmission

In this paper, we provide a quantitative analysis of the effect of improving the throughput characteristics by installation of a sequence control buffer in the receiver applied to the continuous ARQ (go-back-N) scheme, which is a typical method of transmission control in data communication networks, for the case when a simultaneous retransmission of multiple copies is allowed. A known method of improvement of the transmission characteristics is to store the correctly received data blocks in a buffer in cases when error recovery procedures are initiated, although no methods of accurate evaluation under the conditions of a reduced throughput have been proposed. In this paper, the error recovery process is expressed as a two-step hierarchical model. In the analysis model prepared for the purposes of this study, the retransmission cycles repeated for error recovery purposes and retransmission sets corresponding to the continuous error recovery operations are represented in the form of a two-step retransmission diagram. Using this model, we have demonstrated that, based on the 1223-type revised mean-value analysis that allows for the estimation of mean values of the influence between the sets, it is possible to considerably reduce the volume of calculations. Using the proposed method of analysis, it is possible to estimate the actual transmission rate within 2.5% of its absolute value, and the round trip delay with a time-dependent remote control can also be approximated. © 2000 Scripta Technica, Electron Comm Jpn Pt 1, 84(1): 49–58, 2001

Study size and documentation to detect injection-related hepatitis C in prison.

We used existing data on hepatitis C prevalence, injection-related hepatitis C transmission and needle use in prisons and new data on infectiousness, to estimate the size of study required to detect injection-related hepatitis C in UK prisons. A pilot study of 500 prisoners followed for 10 weeks would have a 65% chance of detecting a hepatitis C seroconversion, conservatively assuming one injection per prisoner per week, and a 3% transmission rate per injection, but uncertainty might persist as to whether transmission had occurred during a short incarceration or before it. If the actual transmission rate was 10%, as recently documented, then such a study would have more adequate statistical power. A definitive study of 3000 prisoners for 10 weeks would expect to detect about six seroconversions, even with conservative estimates of injection frequency and transmission rate. Adequate design and power of these studies is important because of the complacency that could result from false-negative findings. We suggest six risk-factor themes that studies should document.