Performance evaluation of flooding in MANETs in the presence of multi-broadcast traffic

Broadcasting has many important uses and several mobile ad hoc networks (MANETs) protocols assume the availability of an underlying broadcast service. Applications, which make use of broadcasting, include LAN emulation, paging a particular node. However, broadcasting induces what is known as the "broadcast storm problem" which causes severe degradation in network performance, due to excessive redundant retransmission, collision, and contention. Although probabilistic flooding has been one of the earliest suggested approaches to broadcasting. There has not been so far any attempt to analyse its performance behaviour in MANETs. This paper investigates using extensive ns-2 simulations the effects of a number of important parameters in a MANET, including node speed, pause time and, traffic load, on the performance of probabilistic flooding. The results reveal that while these parameters have a critical impact on the reachability achieved by probabilistic flooding, they have relatively a lower effect on the number of saved rebroadcast packets

Performance evaluation of adjusted probabilistic broadcasting in MANETs

Appropriate use of a probabilistic broadcasting method in MANETs can decrease the number of rebroadcasts, and as a result reduce the opportunity of contention and collision among neighbouring nodes. In this paper we evaluate the performance of adjusted probabilistic flooding by comparing it to "simple" flooding as used with the ad hoc on demand distance vector (AODV) routing protocol as well as a fixed probabilistic approach. The results reveal that the adjusted probabilistic flooding exhibits superior performance in terms of both reachability and saved rebroadcast

Improving route discovery in on-demand routing protocols using local topology information in MANETs

Most existing routing protocols proposed for MANETs use flooding as a broadcast technique for the propagation of network control packets; a particular example of this is the dissemination of route requests (RREQs), which facilitate route discovery. In flooding, each mobile node rebroadcasts received packets, which, in this manner, are propagated network-wide with considerable overhead. This paper improves on the performance of existing routing protocols by reducing the communication overhead incurred during the route discovery process by implementing a new broadcast algorithm called the adjusted probabilistic flooding on the Ad-Hoc on Demand Distance Vector (AODV) protocol. AODV [3] is a well-known and widely studied algorithm which has been shown over the past few years to maintain an overall lower routing overhead compared to traditional proactive schemes, even though it uses flooding to propagate RREQs. Our results, as presented in this paper, reveal that equipping AODV with fixed and adjusted probabilistic flooding, instead, helps reduce the overhead of the route discovery process whilst maintaining comparable performance levels in terms of saved rebroadcasts and reachability as achieved by conventional AODV\@. Moreover, the results indicate that the adjusted probabilistic technique results in better performance compared to the fixed one for both of these metrics

Enhanced Cluster Based Routing Protocol for MANETS

Mobile ad-hoc networks (MANETs) are a set of self organized wireless mobile nodes that works without any predefined infrastructure. For routing data in MANETs, the routing protocols relay on mobile wireless nodes. In general, any routing protocol performance suffers i) with resource constraints and ii) due to the mobility of the nodes. Due to existing routing challenges in MANETs clustering based protocols suffers frequently with cluster head failure problem, which degrades the cluster stability. This paper proposes, Enhanced CBRP, a schema to improve the cluster stability and in-turn improves the performance of traditional cluster based routing protocol (CBRP), by electing better cluster head using weighted clustering algorithm and considering some crucial routing challenges. Moreover, proposed protocol suggests a secondary cluster head for each cluster, to increase the stability of the cluster and implicitly the network infrastructure in case of sudden failure of cluster head.Comment: 6 page

On the performance of probabilistic flooding in mobile ad hoc networks

This paper investigates using extensive simulations the effects of a number of important system parameters in a typical MANETs, including node speed, pause time, traffic load, and node density on the performance of probabilistic flooding. The results reveal that most of these parameters have a critical impact on the reachability and the number of saved rebroadcast messages achieved by probabilistic flooding, prompting the need for dynamically adjusting nodal retransmission probabilities depending on the current state of the network

Hot climate effects and their amelioration on some productive and reproductive traits in rabbit does

[EN] This study aimed to improve productive and reproductive performance of female rabbit does during the summer season hot climate using vitamin C or cooled water in combination with equine chorionic gonadotropin (eCG) treatment. Sixty New Zealand White rabbit does were assigned to three groups, according to drinking-water treatment: 1) fresh tap water without any supplementation (control, C), 2) cooled drinking water (10-15ºC) (CW), and 3) fresh tap water supplemented daily with added ascorbic acid (1 g/L) (vitamin C). Twenty four hours before mating, does of each group were randomly divided into two subgroups; H does were intravenously injected with 40 IU/doe eCG, while NH does did not receive any hormonal treatment. Productive and reproductive performance were signifi cantly (P<0.05) improved in the treated groups. Kit weights at kindling and weaning were greater (P<0.05) in both vitamin C and cooled water groups than in the control regardless of hormonal treatment. It is worthy noticed that conception rate and litter size at birth were adversely affected by eCG, especially in does drinking vitamin C. The percentage of mature oocytes was lower (P<0.01) in control than in treated groups. The oocyte maturation rate improved after treatment with vitamin C to reach 80% compared to 66% in control group. In conclusion, cool drinking water or vitamin C is recommended for alleviating heat stress during summer in rabbits.Yassein, S.; Mahmoud, KM.; Maghraby, N.; Ezzo, O. (2008). Hot climate effects and their amelioration on some productive and reproductive traits in rabbit does. World Rabbit Science. 16(3). doi:10.4995/wrs.2008.62616

Total petroleum hydrocarbons in water, sediment, and Redbelly tilapia, Coptodon zillii in Shatt Al-Basrah Canal, Iraq

Water pollution is one of the most common global problems resulting from increased industrial and agricultural activities. Petroleum hydrocarbons have extremely dangerous to the aquatic environment. The total petroleum hydrocarbon (TPHs) was investigated in water, sediment, and muscles of Coptodon zillii at Abu Sakhir and Al-Zubair Bridge stations seasonally in the Shatt al-Basra Canal. The results showed a variation in the TPHs levels in the studied stations. In addition, a significant difference in the TPHs was recorded during the seasons in the water, and sediments between stations. The results showed significant differences in the TPHs in the muscles in the spring but no significant in other seasons between the two stations. The results of the lipid contents of fish revealed significant differences between the two studied stations in the fall, spring, and summer seasons but not significant in winter.&nbsp

Diagnosis of Cryptococcus neoformans from the milk of goat using Multiplex PCR as diagnostic tool

Cryptococcus neoformans (C. neoformans) is distributing globally. It is an opportunistic saprophytic fungal pathogen that appears as a dimorphic yeast-like fungus. It causes a wide variety of cryptococcal reports have been recorded the isolation of Cryptococcus neoformans from the milk of the mastitic goat in Iraq. Consequently, this study intends to isolate C. neoformans from the milk of goats that suffered from clinical and subclinical mastitis in Iraq. Three hundred milk specimens were collected from 163 mastitic and apparently healthy goats. All milk samples were subjected to conventional isolation and characterization tests, moreover, multiplex polymerase chain reaction (mPCR) was used to confirm the diagnosis. The total positive ratio of mycotic mastitis was 41.33% for all tested samples. The total number of yeast isolates was 69 (55.64 %), meanwhile, C. neoformans rate was 7.24% (5 out of 69). Multiplex polymerase chain reaction confirmed 5 C. neoformans isolates. The results of this study revealed an agreement between the mPCR technique and conventional methods in the diagnosis of Cryptococcus neoformans. In conclusion, the results of this study approved the isolation of Cryptococcus neoformans from the milk of clinical and subclinical mastitis of goats in Iraq. The authors recommend doing a further future study that includes a large number of goats and from different locations, to investigate the actual situation of Cryptococcus neoformans infection in caprine in Iraq using mPCR technique

A performance comparison of smart probabilistic broadcasting of ad hoc distance vector (AODV).

Broadcast is a common operation used in Mobile Ad hoc Networks (MANETs) for many services, such as, routdiscovery and sending an information messages. The direct method to perform broadcast is simple flooding, which itcan dramatically affect the performance of MANET. Recently, a probabilistic approach to flooding has beenproposed as one of most important suggested solutions to solve the broadcast storm problem, which leads to thecollision, contention and duplicated messages. This paper proposed new probabilistic method to improve theperformance of existing on-demand routing protocol by reduced the RREQ overhead during rout discoveryoperation. The simulation results show that the combination of AODV and a suitable probabilistic rout discoverycan reduce the average end- to- end delay as well as overhead and still achieving low normalized routing load,comparing with AODV which used fixed probability and blind floodin

ANTIVIRAL AND IMMUNE STIMULANT ACTIVITIES OF GLYCYRRHIZIN AGAINST DUCK HEPATITIS VIRUS

This study was conducted to investigate the effect of glycyrrhizin as an immune stimulant against duck hepatitis virus (DHV). In vitro study was carried out to determine cytotoxic and antiviral effects of glycyrrhizin in VERO cells. In vivo study was performed on 40 one-day-old White Pekin ducklings. –and the birds weres divided into 4 groups: control, glycyrrhizin treated, vaccinated with live attenuated DHV vaccine and glycyrrhizin treated and vaccinated; to investigate the changes in immunity and challenge test. Blood samples were collected from each duckling for evaluation of cellular and humeral immunity. The in vitro results revealed that glycyrrhizin had antiviral and no toxic effects till 106 dilutions. Higher antibody titer was observed from the 5th week till the end of experiment in glycyrrhizin and vaccinated group. Treatment with glycyrrhizin alone or with DHV vaccine demonstrated a pronounced lymphocytic proliferation response after 4 days post-inoculation till the end of experiment, while vaccinated group revealed a pronounced proliferation response after 24 days post-inoculation. Treatment with glycyrrhizin alone or combination with DHV vaccine revealed good immune stimulant and antiviral effect against DHV