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    Volume 1 Number 2 July 2015

    A Dynamic Cellular Automaton Model for Large-Scale Pedestrian Evacuation


    Pages: 36-44
    Authors: Lim Eng Aik ; Tan Wee Choon ; Mohd. Syafarudy Abu
    Abstract
    An existing dynamic cellular automaton (CA) model is modified for simulating the hallway area evacuation experiment. In this proposed model, some basic parameters that plays and important role in evacuation process such as human psychology and pedestrian density around exits are considered. From the simulation and experimental results obtained, it shows that the modification provides a reasonable improvement as pedestrian also tends to select exit route according to occupant density around the exits area besides considering the spatial distance to exits. The studies on pedestrian density effects on speed during the evacuation process are performed. Comparison for both the experiment and simulation results verifies that the proposed model is able to effectively reproduce the experiment. The proposed CA model improvement is valuable for more extensive application study and aid the architectural design to increase public safety. Hence, we conclude our paper by presenting some of the application from the proposed model in conjunction to forecast the particular adjustment to the hallway area that would improve the output of the model.



    Extending TCP the Major Protocol of Transport Layer


    Pages: 21-35
    Authors: Ashis Saklani ; Vishal Gupta
    Abstract
    As We’ve  known  for  a  while  that  the  Internet  is classified as a  result  of  the  race  to  optimise  existing  applications  or  en- hance security. Sometimes  NATs, performance-enhancing-proxies, firewalls  and  traffic  normalizers  are  only  a  few  of  the  middle-  boxes that are deployed in the network and look beyond the IP header to do their job. IP itself can’t be extended because  "IP options are not an option" [1]. Is the same true for TCP?  In this Research  we develop a  methodology for  evaluating  middlebox  behavior  relating  to  TCP  extensions  and present the results of measurements conducted from multiple  Survival  points.   The  shortest  answer  is  that  Yes we  can  still extend TCP, but extensions’ design is very constrained as it needs  to  take  into  account  prevalent  middlebox  behaviors.  For instance, absolute sequence numbers cannot be embedded in options, as middleboxes can rewrite ISN and preserve undefined options.  Sequence  numbering  also  must  be  consistent  for  a  TCP  connection,  because  many  middleboxes  only allow through contiguous flows.  We used these findings to analyze three proposed extensions to TCP. We find that MPTCP is likely to work correctly in the Internet or fall-back to regular TCP. TcpCrypt seems ready to be deployed, however it is fragile if resegmentation does happen for instance with hardware offload.   Finally,  TCP  extended  options  in  its  current  form  is  not  safe  to  deploy.



    Multidrug Resistance Pattern of Staphylococcus Aureus Isolates in Maiduguri Metropolis


    Pages: 16-20
    Authors: Ismail, H. Y. ; Bello, H. S. ; Mustafa, A. ; Adamu, A.
    Abstract
    Multi drug-resistant (MDR) isolates of Staphylococcus aureus are on rise and are becoming a challenge for timely and appropriate treatment. The present study was carried out with an objective to isolate Staphylococcus aureus from clinical samples and determine their sensitivity. Out of 110 samples collected, 44 were shown to contained S. aureus. The isolates were subjected to antibiotic sensitivity tests using 10 different and commonly used antibiotics by modified Kirby- Bauer disc diffusion technique. Out of the total isolates (42) tested, only 7.1% were susceptible to all the antibiotics. Multiple resistance was eminent in over 92% with highest occurrence in 4.8% where the entire antibiotics were resisted. Multiple antibiotic resistance indixes (MAR index) indicated that 0.6 index occurred most (23.8%) followed by 0.5 (19.0%). On the other hand, 0.1 and 0.8 indexes were the lowest with 0.0% and 1.0% occurrence respectively. Ciprofloxacin was resisted by most of the organisms (64.3%) while amoxicillin (64.3%) and streptomycin (61.9%) were most efficacious. With over 90% isolate having MAR index ≥ 0.2, the multiple drug resistance by the S. aureus is quite alarming and might suggest inappropriate antibiotic usage by the sampled population. Therefore, the need to strategize the nature of antibiotic treatment against S. aureus and massive campaign on indiscriminate antibiotic use is urgent.