Time division multiple access scheduling strategies for emerging vehicular ad hoc network medium access control protocols: a survey

[EN] Vehicular ad hoc network (VANET) is an emerging and promising technology, which allows vehicles while moving on the road to communicate and share resources. These resources are aimed at improving traffic safety and providing comfort to drivers and passengers. The resources use applications that have to meet high reliability and delay constraints. However, to implement these applications, VANET relies on medium access control (MAC) protocol. Many approaches have been proposed in the literature using time division multiple access (TDMA) scheme to enhance the efficiency of MAC protocol. Nevertheless, this technique has encountered some challenges including access and merging collisions due to inefficient time slot allocation strategy and hidden terminal problem. Despite several attempts to study this class of protocol, issues such as channel access and time slot scheduling strategy have not been given much attention. In this paper, we have relatively examined the most prominent TDMA MAC protocols which were proposed in the literature from 2010 to 2018. These protocols were classified based on scheduling strategy and the technique adopted. Also, we have comparatively analyzed them based on different parameters and performance metrics used. Finally, some open issues are presented for future deployment.Tambawal, AB.; Noor, RM.; Salleh, R.; Chembe, C.; Anisi, MH.; Michael, O.; Lloret, J. (2019). Time division multiple access scheduling strategies for emerging vehicular ad hoc network medium access control protocols: a survey. Telecommunication Systems. 70(4):595-616. https://doi.org/10.1007/s11235-018-00542-8S59561670

[Disability] justice dictated by the surfeit of love:Simone Weil in Nigeria

How is Nigeria’s failure to fulfil its obligations as a signatory of the United Nations Convention on the Rights of Persons with Disabilities to be appreciated or even resolved? Answers to this are sought through a seminal criticism of human rights, namely, Simone Weil’s 1942 essay Human Personality. Weil questioned the ability of human rights concepts to cause the powerful to develop the emotional dispositions of empathy for those who suffer. Weil’s insights provide a convincing explanation that the indifference of Nigerian authorities towards the Convention may be accounted for by the weakness of human rights discourse to foster human capacity for empathy and care for those who suffer. Weil’s criticisms will serve as a point of departure for a particular way to circumvent this inadequacy of human rights discourse to achieve disability justice in Nigeria through other means. I argue that Weil, through her concept of attention, grappled with and offers a consciousness of suffering and vulnerability that is not only uncommon to existing juridical human rights approaches, but is achievable through the active participation in the very forms of suffering and vulnerability in which amelioration is sought. To provide empirical content to this argument, I turn to a short-lived initiative of the Nigerian disability movement, which if ethico-politically refined and widely applied, can supply an action-theoretical grounding for and be combined with Weil’s work to elevate agitations for disability justice above human rights to the realm of human obligations

Association of HIV-induced immunosuppression and clinical malaria in Nigerian adults

Background: Despite the growing body of evidence on the interaction between HIV and malaria in sub-Saharan Africa, there is a dearth of data on clinical malaria in HIV-infected patients in Nigeria. We determined the burden of clinical malaria in HIV-infected adult Nigerians and further investigated the association between their immunological status and the rates of clinical malaria. Methods: Ninety seven antiretroviral treatment-naïve HIV-infected adults were enrolled in a cross-sectional study from August to December, 2009. The participants had a complete clinical evaluation, thick and thin blood films for malaria parasites and CD4 cell count quantification. Clinical malaria was defined as having fever (temperature ≥ 37.5oC or history of fever within 48 hours) and a malaria parasite density above the median value obtained for subjects with co-existing fever and parasitaemia. Results: Clinical malaria was diagnosed in 10 out of 97 patients (10.3%). Lower CD4 cell counts were associated with increasing rates of clinical malaria which was 0% at CD4 cell count of ≥ 500, 2.6% at 200-499 and 30% a

QoE prediction model for multimedia services in intelligent transport system / Oche Michael

Vehicular ad hoc networks (VANETs), present an intriguing platform for applications like Intelligent Transportation System (ITS), Infotainment applications including but not limited to, live video streaming, file sharing, mobile office advertisements and even distributed computer games. These conceivable ITS and infotainment applications aspire to be a prevalent mode of communication among vehicles while on the road. However, Impact of such anticipated increased in communication among vehicles, is bound to have increased contention on communication links resulting in variable service quality for different applications. A mechanism is needed to manipulate the allocation of the network resources to meet these application traffic demands. Before now, the most prominent approach used to differentiate network traffic flow was Quality of Service (QoS). But then, QoS mainly focuses on objective measurement of network parameter such as jitter, throughput, loss and delay, but pay less attention to how users of the network perceived the service delivery quality. Studies have shown that the traditional QoS approach for evaluating network service quality is not sufficient, and so calls for a more exhaustive and comprehensive quality assessment approach that is not entirely based on network parameter measurement, but one that also include the end user perception of service quality. This quality assessment approach is known as Quality of Experience (QoE). Though, absolute QoE assessment requires a subjective approach, however, performing a subjective test to evaluate the quality of real-time multimedia services is expensive in terms of time and resources and hard to carry out in real-time. The process involves in subjective approach requires a controlled environment, such controlled environment is not realistic in a complex network environment such as VANETs. Therefore, the iv only practical solution during service operation is to apply an objective quality assessment model, which produces an estimate of the perceived quality without human involvement. Hence, in this thesis, a QoE prediction model that estimates the QoE of ITS multimedia services over VANETs objectively, was proposed. The proposed model is based on a state space approach and advanced statistics method, in conjunction with ordinal regression analysis, that estimates the perceived ITS multimedia service quality as a function of aggregated QoE influential factors. The multimedia/ITS distribution network was segmented into a theoretical explanation of three quality optimization component, to develop a QoE optimization function, which takes into consideration the service source quality, the network resource constraint and the human and context factors in defining the overall QoE. The result indicates to be promising, as the proposed model exhibits good predictive power that is coherent with the observed dat

Enhanced weight-based clustering algorithm to provide reliable delivery for VANET safety applications.

A vehicular ad hoc network (VANET) is an emerging and promising wireless technology aimed to improve traffic safety and provide comfort to road users. However, the high mobility of vehicles and frequent topology changes pose a considerable challenge to the reliable delivery of safety applications. Clustering is one of the control techniques used in VANET to make the frequent topology changes less dynamic. Nevertheless, research has shown that most of the existing clustering algorithms focus on cluster head (CH) election with very few addressing other critical issues such as cluster formation and maintenance. This has led to unstable clusters which could affect the timely delivery of safety applications. In this study, enhanced weight-based clustering algorithm (EWCA) was developed to address these challenges. We considered any vehicle moving on the same road segment with the same road ID and within the transmission range of its neighbour to be suitable for the cluster formation process. This was attributed to the fact that all safety messages are expected to be shared among the vehicles within the vicinity irrespective of their relative speedto avoid any hazardous situation. To elect a CH, we identified some metrics on the basis of the vehicle mobility information. Each vehicle was associated with a predefined weight value based on its relevance. A vehicle with the highest weight value was elected as the primary cluster head (PCH). We also introduced a secondary cluster head (SeCH) as a backup to the PCH to improve the cluster stability. SeCH took over the leadership whenever the PCH was not suitable for continuing with the leadership. The simulation results of the proposed approach showed a better performance with an increase of approximately40%- 45% in the cluster stability when compared with the existing approaches. Similarly, cluster formation messages were significantly minimized, hence reducing the communication overhead to the system and improving the reliable delivery of the safety applications

Evaluation of the effect of a modified proprietary poultry feed on cholesterol excretion in laying birds

The effect of modified proprietary poultry feed on cholesterol excretion in laying birds was evaluated. The study sort to lower the cholesterol content of eggs at the point of their physiological formation via a modification of the proprietary feed fed to laying poultry birds. This was with a view to lower the net cholesterol content in their eggs, thereby lowering the cholesterol levels available in such eggs for intake upon consumption. A 20% rice bran modification of the proprietary feed was made. Animal subjects were divided into experimental and control groups and the mean total cholesterol in their faecal droppings where determined before and after varying their feeding programs. Whereas the experimental group was fed with the modified feed, the control group was maintained on the unmodified feed. Enzymatic colorimetric method was used for the determination of mean total cholesterol in the dried faecal droppings of each group of birds under investigation. The results showed that the mean total cholesterol excretion before and after the modified feed regimen were 5.97±0.16 mg/g and 9.99±0.47 mg/g respectively and were found to be significantly different when compared using a t-test at p > 0.05 and 49 degree of freedom The results also showed that the modified proprietary poultry feed increased total cholesterol excretion in the faecal droppings of laying birds fed with the modified feed by 67.3%, and this was found to be statistically significant at p > 0.05. Hence, a 20% rice-bran modification of the proprietary feed yields a modified feed with a proven potency in elevating total cholesterol excretion while producing no drastic deviation from the proximate composition of the unmodified proprietary feed and is thus likely to have no adverse effect on the productivity of laying birds