A Taxonomy for Congestion Control Algorithms in Vehicular Ad Hoc Networks

One of the main criteria in Vehicular Ad hoc Networks (VANETs) that has attracted the researchers' consideration is congestion control. Accordingly, many algorithms have been proposed to alleviate the congestion problem, although it is hard to find an appropriate algorithm for applications and safety messages among them. Safety messages encompass beacons and event-driven messages. Delay and reliability are essential requirements for event-driven messages. In crowded networks where beacon messages are broadcasted at a high number of frequencies by many vehicles, the Control Channel (CCH), which used for beacons sending, will be easily congested. On the other hand, to guarantee the reliability and timely delivery of event-driven messages, having a congestion free control channel is a necessity. Thus, consideration of this study is given to find a solution for the congestion problem in VANETs by taking a comprehensive look at the existent congestion control algorithms. In addition, the taxonomy for congestion control algorithms in VANETs is presented based on three classes, namely, proactive, reactive and hybrid. Finally, we have found the criteria in which fulfill prerequisite of a good congestion control algorithm

Session Initiation Protocol Attacks and Challenges

In recent years, Session Initiation Protocol (SIP) has become widely used in current internet protocols. It is a text-based protocol much like Hyper Text Transport Protocol (HTTP) and Simple Mail Transport Protocol (SMTP). SIP is a strong enough signaling protocol on the internet for establishing, maintaining, and terminating session. In this paper the areas of security and attacks in SIP are discussed. We consider attacks from diverse related perspectives. The authentication schemes are compared, the representative existing solutions are highlighted, and several remaining research challenges are identified. Finally, the taxonomy of SIP threat will be presented

Intravitreal Expansile Gas and Bevacizumab Injection for Submacular Hemorrhage Due to Neovascular Age-related Macular Degeneration

Purpose: To evaluate the results of intravitreal expansile gas injection, with or without recombinant tissue plasminogen activator (rtPA), followed by intravitreal bevacizumab injection for treatment of submacular hemorrhage (SMH) secondary to neovascular age-related macular degeneration (AMD). Methods: In this interventional case series, 5 eyes of 5 patients with SMH secondary to choroidal neovascularization (CNV) due to neovascular AMD were treated with 0.3 cc intravitreal SF6 (and 50 μg of rtPA in two eyes), followed by face-down positioning; 24 hours later, 1.25 mg of bevacizumab was injected intravitreally. Main outcome measures included displacement of SMH and best corrected visual acuity (BCVA). Results: Mean patient age was 75.6±9.2 (range, 60-83) years, mean duration of symptoms was 6.4±3.2 (range, 3-10) days, and mean number of bevacizumab injections was 1.8 (range, 1-3). Mean preoperative BCVA was 1.28±0.27 logMAR which improved significantly to 0.57±0.33 logMAR at 12 months (P=0.042). SMH displacement occurred in all eyes, and visual acuity improved and remained stable during the follow-up period of 12 months. Conclusion: Intravitreal expansile gas injection, with or without rtPA, followed by intravitreal bevacizumab injection, seems to be an effective modality for SMH displacement and treatment of the underlying CNV in neovascular AMD

Effect of Complement Factor B Gene Polymorphisms on Age-Related Macular Degeneration in North-East of Iran Population

Aims: Age-related macular degeneration (AMD) is the most prevalent cause of irreversible blindness and debilitating in old stages, in developed and developing countries that engage the central part of the retina or macula. The aim of this study was to evaluate the relationship of the rs4151667 position of the complement factor B gene polymorphism with AMD (dry type with geographic atrophy phenotype) in the North East of Iran population. ­Materials & Methods:­ In this descriptive cross-sectional study in 2015-2016, 44 AMD patients (dry type with geographic atrophy phenotype) were randomly selected from Gonabad City, Iran, health centers as the patient group. 50 healthy individuals from the same society that have no relative relations with each other or the patients, but were adapted by age and sex to the patient group, were selected as the control group. The ­­polymorphism of rs4151667 (c.26T>A)­ position of the complement factor B gene was determined for all samples by Restriction Fragment Length Polymorphism (RFLP). Data was analyzed the Chi-square test in 2x2.Contingency software. Findings: The frequency of TT genotype in AMD patients (95.5%) was significantly (p=0.048) more than the control group (88.0%), but the frequency of AT genotype in AMD patients (4.5%) was significantly (p=0.025) less than the control group (12.0%). Conclusion: The polymorphism of rs4151667 (c.26T>A) position of complement factor B is effective on the development of AMD in North East of Iran population

Genetic Mapping of Modifiers in Prenatal Lethal Tgfb1 Knockout Mice

This thesis presents data obtained from genetic analysis of TGFB1 knockout neonates (Shull et al., 1992, Kulkarni et al., 1993) bred onto different genetic backgrounds. TGFB1(-/-) embryos were initially reported to develop to term normally and die by 3 weeks due to multisystemic inflammation (Shull et al., 1992; Kulkarni et al., 1993). Therefore, it was suggested that TGFB1 was not vital during embryogenesis. However, an independent group (Dickson et al., 1995) demonstrated the implication of TGFB1 in an early stage of embryogenesis. It was shown that 50% of the TGFB1(-/-) embryos died in uterus due to defects in yolk sac vasculogenesis and haematopoiesis, whereas the rest did not succumb to the yolk sac phenotype but developed to term normally and died by 3 weeks post-partum as described previously (Kulkarni et al 1993). It has also been shown that maternal TGFB1 can cross the placenta (Letterio et al., 1994). TGFB1 was detected in TGFB1(-/-) embryos born to TGFB1(+/-) females, whereas in those born to null females, TGFB1 was not detected. Thus, it has been suggested that Tgfb1 gene knockout was not equivalent to a protein knockout and the maternally acquired protein could rescue TGFB1(-/-) foetuses and embryos. The work accomplished in this project set out to determine the reason for the existence of at least two different phenotypes; yolk sac insufficiency and survival to birth, among TGFB1(-/-) conceptuses. During this study, the involvement of several possible genetic and/or non-genetic modifying factors in the different expressivity of the TGFB1(-/-) phenotype was examined. The phenotype of TGFB1(-/-) was studied by breeding the Tgfb1 null allele onto two inbred strains; NIH/Ola and C57BI/6J/Ola. Also TGFB1(-/+) heterozygous crosses between various combinations of NIH/Ola and C57BI/6J/Ola enabled study of the possible implications of maternal factors in the different expressivity of the TGFB1(-/-) phenotype. It was estimated that one locus with a codominant pattern of inheritance was responsible for the different expressivity. Due to the codominant behaviour of the modifying gene(s), the F2(NIH/Ola x C57BI/6J/Ola) intercross animals were considered to be the most informative animals for genetic linkage analysis. 50 polymorphic DNA markers were utilised to initiate a genome-wide search by screening 50 TGFB1(-/-) neonates from an F1 intercross. More than 90% of the genome was screened for modifying gene(s) during this study. Four regions of the genome showed suggestive linkage (P<0.05) in the first screen. To confirm the linkages, 30 extra null animals were screened with the interested markers. A small region of mouse chromosome 5 harbouring a genetic modifier met the criterion of definitive linkage (P?10-5). During this project, the feasibility of mapping genetic factors involved in determining early embryonic lethality without need to access the embryos was demonstrated. Fibroblast growth factor receptor type 3 {Fgfr3) and Fibroblast growth factor inducible gene 13 (Fin13), which mapped in the vicinity of the modifying gene, were considered as candidate genes. The expression of these genes were assessed in 9.5 d.pc. embryos and yolk sacs bred onto either NIH/Ola or C57BI/6J/Ola strains by application of RT-PCR. Also expression of Transforming growth factor beta I (Tgfb1) gene was examined in 9.5 d.pc both yolk sac and embryo bred onto either of the strains. By application of heteroduplex analysis (HA) and direct DNA sequencing, the possibility of genetic polymorphism within Fin13 between the two mouse strains was investigated over the coding region. The latter part of the thesis presents data about the genetical mapping of Transforming Growth Factor Beta type II receptor (Tgfbr2) and Plasminogen activator inhibitor type I (PlanHI) on the mouse genome. Following the mapping Tgfbr2 on the mouse genome, two uncloned mouse mutants which mapped in the vicinity of the Tgfbr2 location were examined, by Southern blotting, for the possibility of a large deletion in Tgfbr2 gene in either of these mutants

A framework and mathematical modeling for the vehicular delay tolerant network routing

Vehicular ad hoc networks (VANETs) are getting growing interest as they are expected to play crucial role in making safer, smarter, and more efficient transportation networks. Due to unique characteristics such as sparse topology and intermittent connectivity, Delay Tolerant Network (DTN) routing in VANET becomes an inherent choice and is challenging. However, most of the existing DTN protocols do not accurately discover potential neighbors and, hence, appropriate intermediate nodes for packet transmission. Moreover, these protocols cause unnecessary overhead due to excessive beacon messages. To cope with these challenges, this paper presents a novel framework and an Adaptive Geographical DTN Routing (AGDR) for vehicular DTNs. AGDR exploits node position, current direction, speed, and the predicted direction to carefully select an appropriate intermediate node. Direction indicator light is employed to accurately predict the vehicle future direction so that the forwarding node can relay packets to the desired destination. Simulation experiments confirm the performance supremacy of AGDR compared to contemporary schemes in terms of packet delivery ratio, overhead, and end-to-end delay. Simulation results demonstrate that AGDR improves the packet delivery ratio (5-7%), reduces the overhead (1-5%), and decreases the delay (up to 0.02 ms). Therefore, AGDR improves route stability by reducing the frequency of route failures. © 2016 Mostofa Kamal Nasir et al

Primary Care's Historic Role in Vaccination and Potential Role in COVID-19 Immunization Programs

Purpose: COVID-19 pandemic recovery will require a broad and coordinated effort for infection testing, immunity determination, and vaccination. With the advent of several COVID-19 vaccines, the dissemination and delivery of COVID-19 immunization across the nation is of concern. Previous immunization delivery patterns may reveal important components of a comprehensive and sustainable effort to immunize everyone in the nation. Methods: The delivery of vaccinations were enumerated by provider type using 2017 Medicare Part B Fee-For-Service data and the 2013-2017 Medical Expenditure Panel Survey. The delivery of these services was examined at the service, physician, and visit level. Results: In 2017 Medicare Part B Fee-For-Service, Primary Care Physicians provided the largest share of services for vaccinations (46%), followed closely by Mass Immunizers (45%), then NP/PAs (5%). The Medical Expenditure Panel Survey showed that Primary Care Physicians provided most clinical visits for vaccination (54% of all visits). Conclusions: Primary Care Physicians have played a crucial role in delivery of vaccinations to the U.S. population, including the elderly, between 2012-2017. These findings indicate primary care practices may be a crucial element of vaccine counseling and delivery in the upcoming COVID-19 recovery and immunization efforts in the United States.http://deepblue.lib.umich.edu/bitstream/2027.42/166088/1/874-20V3_PP.pdfDescription of 874-20V3_PP.pdf : Main ArticleSEL

Ant colony optimization for vehicle traffic systems: applications and challenges

Ant-based algorithms simulate the cooperative behaviour of real ants in finding food resources. A significant number of studies have focused on the self-organised behaviour of ants in the natural environment to develop effective systems for dynamic problems. Ant-based systems have special properties such as scalability, adaptability, and dynamicity, which are the main requirements for solving vehicle traffic congestion problem. Thus, ant-based algorithms are now being adopted by vehicle traffic systems VTSs to guide vehicles to less congested paths. However, literature shows that comprehensive reviews are lacking in this field. The main contribution of this paper is the review and classification of the most relevant systems based on novel taxonomy. A survey that includes statistical analyses on ant-based VTS was conducted to identify the limitations and evaluation process of VTS. This paper concludes by proposing a general framework in applying ant colony optimisation to VTS

Intelligent Advisory Speed Limit Dedication in Highway Using VANET

Variable speed limits (VSLs) as a mean for enhancing road traffic safety are studied for decades to modify the speed limit based on the prevailing road circumstances. In this study the pros and cons of VSL systems and their effects on traffic controlling efficiency are summarized. Despite the potential effectiveness of utilizing VSLs, we have witnessed that the effectiveness of this system is impacted by factors such as VSL control strategy used and the level of driver compliance. Hence, the proposed approach called Intelligent Advisory Speed Limit Dedication (IASLD) as the novel VSL control strategy which considers the driver compliance aims to improve the traffic flow and occupancy of vehicles in addition to amelioration of vehicle’s travel times. The IASLD provides the advisory speed limit for each vehicle exclusively based on the vehicle’s characteristics including the vehicle type, size, and safety capabilities as well as traffic and weather conditions. The proposed approach takes advantage of vehicular ad hoc network (VANET) to accelerate its performance, in the way that simulation results demonstrate the reduction of incident detection time up to 31.2% in comparison with traditional VSL strategy. The simulation results similarly indicate the improvement of traffic flow efficiency, occupancy, and travel time in different conditions