A new fair marker algorithm for DiffServ networks

Internet Engineering Task Force (IETF) has proposed many new technologies to cover the new real time applications which have become very important in today's Internet demands. One such technology is Differentiated Services (DiffServ). DiffServ routers provide Per Hop Behaviors (PHBs) to aggregate traffic for different level of services. There is an unfairness problem that occur in a DiffServ networks. In this paper an improved version of the time sliding window three color marker is proposed and analyzed. The proposed algorithm is based on the adaptability concept of changing the constant value in the previous version of the algorithm (ItswTCM), in other words, changing the limit for the constant value without affecting the simplicity of the algorithm. The paper design and implement the algorithm with extensive simulations using NS-2 simulator to compare the proposed algorithm with previous algorithms. Results show that our new marker performs better than previous algorithms such as srTCM, trTCM, tswWTCM and ItswTCM in terms of fairness and number of yellow packets injected to the network in proportion to the committed rate

Validating reliability of OMNeT++ in wireless networks DoS attacks: simulation vs. testbed.

Despite current 802.11i security protocol, wireless net- works are vulnerable to Denial of Service (DoS) attacks. Sending a continuous stream of forgery control frames by an attacker can easily flood wireless channel so that the network cannot be available for its associated users. These attacks are possible because wireless control frames do not carry any cryptographic mechanism to detect and discard forgery frames. In this research in parallel to our experiments, we develop an extension module for wireless DoS attacks using OMNeT ++ to assess the reliability of this simulation tool in compare to our real 802.11 wireless network testbed. To fulfill these goals, throughput, end- to-end delay, and pocket lost ratio are considered as our performance measures running on both real testbed and simulation model. The results are used as a comparative acceptance of the simulation environment. Hereby we can confirm accuracy of the simulation results and OMNeT ++ in wireless DoS attack domai

Parallel implementation for HSLO(3)-FDTD with message passing interface on distributed memory architecture

Finite-Difference Time-Domain (FDTD) method is a numerical method that can be used to solve electromagnetic problems in time domain. However, this method needs large computer memory and long execution time. Recently, a new scheme of FDTD has been develop which is called the High Speed Low Order (3) FDTD (HSLO(3)-FDTD) method which reduced the speed of FDTD method by 67%. In this paper, we develop the parallel distributed version of the HSLO (3)-FDTD method on Distributed Memory Architecture Machine (Sunfire V1280) with message passing interface. We execute some numerical simulations by a new method with direct-domain (DD) approach to simulate one dimensional free space wave propagation represented by a Gaussian pulse. The simulation is conducted on 2 meter of solution domain truncated by a perfectly conducting boundary condition. The performance of the new schemes are analyzed and compared with the conventional parallel FDTD method in terms of processing time, speed-up, efficiency and cost. The new schemes is shown to be ultra-fast and very efficient with some superlinear speed-up

New approach of solving time-domain free space wave propagation

In this paper, a numerical simulation by a new high speed low order FDTD (HSLO-FDTD) method will be conducted to simulate one dimensional free space wave propagation of 2.4 GHz Gaussian pulse. The efficiency of the new schemes are analyze and compared with the standard FDTD method in terms of processing time, phase velocity and global error. The amplitude in volts by both methods is also displayed. Results obtained using the new schemes compare well with published results and solve the problem faster than the standard FDTD method

Increasing packet delivery in Ad hoc On-Demand Distance Vector (AODV) routing protocol

Broadcasting in the route discovery and the route maintenance of Ad hoc On-demand Distance Vector (AODV) routing protocol provokes a high number of unsuccessful packets deliveries from the source nodes to the destination nodes. Studies have been undertaken to optimize the rebroadcast focused on the route discovery of the AODV. In this study, lifetime ratio (LR) of the active route for the intermediate node is introduced to increase the number of unsuccessful packets delivery. Simulation results focused on the improvement of the packet delivery in the routing protocol compared to standard AODV. The performance metrics are measured by varying the number of nodes and the speeds. The OMNET++ is used to simulate the performance of the metrics

An experimental evaluation of DoS attack and its impact on throughput of IEEE 802.11 wireless networks

a variety of locations. This has lead to development of high level security protocols for WLAN. The newest protocol IEEE 802.11i ratified to provide strong data encryption but it can not prevent Denial of Service (DoS) attacks on WLAN. This paper in a testbed, conducts an experimental framework to implement and quantify common types of DoS attacks against WLAN throughput. The results of implementation of our experiments shows that how easily DoS attacks can be performed on WLAN which causes to reduce throughput of communication considerably to make inaccessible wireless connection for its authorized members

Protocols for secure routing and transmission in mobile ad hoc network: a review

Mobile ad hoc network security is a new area for research that it has been faced many difficulties to implement. These difficulties are due to the absence of central authentication server, the dynamically movement of the nodes (mobility), limited capacity of the wireless medium and the various types of vulnerability attacks. All these factor combine to make mobile ad hoc a great challenge to the researcher. Mobile ad hoc has been used in different applications networks range from military operations and emergency disaster relief to community networking and interaction among meeting attendees or students during a lecture. In these and other ad hoc networking applications, security in the routing protocol is necessary to protect against malicious attacks as well as in data transmission. The goal of mobile ad hoc security is to safeguard the nodes’ operation and ensure the availability of communication in spite of adversary nodes. The node operations can be divided into two phases. The first phase is to discover the route (s) path. The second phase is to forward the data on the available discovered routes. Both stages need to protect from attacks; so many protocols have been proposed to secure the routing and data forwarding. This is a review study to mobile ad hoc protocols for securing routing as well as protocols for securing packets forwarding. Furthermore, it will present the characteristics and the limitations for each protocol and attributes

Gastrointestinal protozoan parasites amongst school children in Inanam, Sabah

Intestinal parasitosis is still an important public health problem. The aim of this study was to determine the prevalence of gastrointestinal protozoan parasites (GIP) in schoolchilden and its association with socio-economic and environmental factors. A series of sample collections for stool was carried out in Sekolah Kebangsaan Inanam II, Kota Kinabalu, Sabah. Samples from 100 schoolchildren were examined by direct smear and formol-ether concentration techniques. The modified Kato-Katz technique was performed to estimate the parasitic burden, expressed in the number of protozoa per gram of stool. The proportion of overall infected samples was 31%. When ranked by proportion, parasite loads were found as follows: Entamoeba histolytica (83.87%), Giardia lamblia (35.48%), Entamoeba coli (22.58%), Entamoeba hartmanni (25.81%), Iodamoeba butschlii (19.35%) and Endolimax nana (6.45%). Both single and double infections in the study had equal percentages (35.48%), followed triple infection (29.03%). There were no significant effects of protozoan infection on weight, height, attendance to school and examination results of the schoolchildren (Independent Group t-Test; p > 0.05). No significant association were found between the protozoan infection and the socio-economic and environmental factors (gender, age, occupation status of mother, house area category and the degree of household crowding). We conclude that the parasitic burden amongst the schoolchildren of Sekolah Kebangsaan Inanam II is minimal and is of less concerned

Hydroxyproline determination for initial detection of halal-critical food ingredients (gelatin and collagen)

Gelatin and collagen are considered halal-critical ingredients as they are typically derived from either bovine or porcine animals. Current analytical methods for determining the sources of gelatin and collagen suffer from limitations in terms of robustness and false positives in peptide matching. Thus, the aim of this study was to investigate the utility of monitoring hydroxyproline, a signature amino acid for gelatin and collagen, for identifying potentially haram foodstuffs. To determine the hydroxyproline profiles among animal- and plant-based samples, one-way univariate analysis of variance followed by pair-wise comparison was used to establish statistical significance. Multivariate chemometric analysis through principal component analysis revealed a discrete distribution pattern among 59 samples due to hydroxyproline variability. Finally, inter- and intra-laboratory comparisons demonstrated the validity and robustness of hydroxyproline determination according to ISO 17025. Thus, this preliminary identification technique will aid the identification of potentially haram foodstuffs