The Ebola Haemorrhagic fever outbreak that occured in Bundibugyo territory in western Uganda between November 2007 and February 2008 had a human death ratio of up to 90 per centum raising superciliums in the wellness sector. Through the usage of Agent Based Modeling and simulation, the research worker seeks to unearth the kineticss refering to the spread and impact of the Ebola Virus that ravaged the people of Bundibugyo territory within that period. It is hoped that the attendant theoretical account will be used as a tool by epidemiologists to foretell the spread of this epidemic in future and therefore debar it in clip.
Over the past century, the mold of the spread of infective diseases has sparked off great involvement from scientists and public wellness professionals ( Quantum leap inventions, 2007 ) . The mold of infective diseases dates back to the twelvemonth 1760 when Daniel Bernouli developed a theoretical account for the transmittal kineticss of little syphilis ( Caldwell and Douglas, 2004 ) .
Rising involvement in complex, non additive systems and high computing machine power of personal computing machines gave birth to Agent Based Modeling and Simulation in the early 1990s ( Gulyas,2005 ) , which has progressively been used to analyze a broad scope of phenomena such as the interaction of different species in an ecosystem.
Agent Based Modeling ( Here after ABM ) is an idealised estimate of how things work in the universe ( Abrahamson and Wilensky, 2005 ) . It is a model for patterning a simulation based on making a set of agents or entities. ( Nikolai and Madey, 2007 ) .The agent may be defined as an abstract or independent determination doing unit with diverse features that uses information collected from its environment to move in a suited mode ( Macal and North, 2006 ) . In mention to mold of epidemics, ABM entails building a simulation in which persons who can travel about in a specific environment are defined harmonizing to a distinguishable set of behavioral regulations and in which the infection occurs in a prescribed manner doing usage of regulations specific to the involved persons.
Macal and North ( 2006 ) explain that an Agent Based Model consists of: A set of agents, a set of agent relationships and a frame work for imitating agent behaviors and interactions
The major end of this research is to do usage of the information obtained about the Ebola Bundibugyo epidemic eruption of Nov 2007 – Feb 2008 and Agent Based Modeling and simulation, to analyze how the Ebola virus might hold spread through the territory of Bundibugyo.
2. Modeling and Simulation
Carson ( 2004 ) defines a theoretical account as a representation of a system or a procedure. He farther states that a simulation theoretical account is a representation that incorporates clip and the alterations that occur as clip goes by. It is a descriptive theoretical account of a procedure that allows survey of the kineticss of a system, alterations that occur over clip and the interactions between the constituents and subsystems.
2.1 Agent-Based Mold
O’Sullivan and Hacklay ( 2000 ) explain that an ABM gets agents from the “ existent universe ” context and topographic points them in a practical universe. The theoretical account could hold several hundred agents programmed with believable regulations regulating their behavior, interacting in this practical environment that represents a existent universe location. The consequences of the theoretical account are so examined to acquire insight into the existent universe state of affairs modeled. Harmonizing to ( Schut 2007 ; Gerhard 1999 ) , an agent is a located, computational and knowing system capable of independent actions in its environment. Being situated implies an agent is in uninterrupted interaction with its environment. Because it is in changeless interaction with an environment, the latter demands action upon the agent within a certain sum of clip. Blaga ( 2008 ) explains that the major thrust in ABMS is to mime the existent universe every bit closely as possible and so develop a laisez faire attitude to see the result.
Axelrod and Testfatsion ( 2005 ) specify it as a method for analyzing systems composed of interacting agents and exhibiting emergent belongingss ( Properties originating from the interaction of the agents that can non be deduced simply through collection of the belongingss of the agents ) .
2.2 Why Agent Based Modeling?
Harmonizing to Bobashev and Epstein ( 2007 ) , ABMs explicitly represent epidemic procedures at the local degree, allowing coevals of macroscopic constructions that can so be compared to informations. They go on to explicate that if the focal point is on epidemic behavior at the local degree, like a little town or small town, equation based theoretical accounts which are an alternate attack may be general and misleading.
Borschchev and Filipov ( 2009 ) argue that ABM is a more general and powerful attack because it enables capturing of more complex constructions and kineticss. They further note that ABM allows and provides for the building of theoretical accounts in the absence of the cognition about the planetary mutualities. Even though the modeller knows excessively small or nil about how things affect each other, if they have some perceptual experience of how the agents behave, they can build the ABM and obtain the planetary behavior.
The most of import advantages of ABMs are that they consider the heterogeneousness of both persons and their environment and integrate the stochastic nature of infective disease transmittal ( Yon et al, 2008 ) . They represent the motion of persons over infinite which is an of import factor to see in extremely contagious diseases ( Perez and Dragicevic, 2009 ) . ABM, which is a bottom-up mold attack, has the advanced capableness of tracking the motion of a disease and the contacts between each person in a societal group located in a geographical country. In comparing to other attacks, ABM facilitates a “ more direct correspondence between the entities in the mark system and the parts of the theoretical account that represent them ( Edmonds, 2000 ) . This is a direct attack that has possible to heighten transparence, soundness, truth and cogency of the mold procedure ( Jose et Al, 2009 ) .
Agent-based simulation, harmonizing to Nathaniel et Al ( 2008 ) is frequently a better tool for probe of public wellness menaces due to the heterogeneousness of populations and travel ensuing from increased globalisation and high mobility. Of great significance is the ability of ABM to take advantage of today ‘s powdered geographic and demographic sets that explicitly represent the existent locations ( such as place, workplaces, health-care installations, and schools ) in which intercessions are used to aim specific populations.
It is due to such potencies that ABM has been adopted in epidemiology to analyze and track the motion of septic persons and their contacts in a societal system ( Dunham, 2005 ) .
2.3 Application of Agent Based patterning in epidemiology
Since origin in the early 1990s, ABM methodological analysiss have been used to analyze a figure of epidemics and infective diseases. Carpenter ( 2004 ) made usage of ABM to analyze the spread of the 1918-1919 Influenza epidemic that is widely believed to hold caused the highest figure of deceases every bit far as grippe is concerned. The ABM attack has besides been used to pattern the spread of HIV/AIDS in populations. Wilensky ( 1997 ) developed a theoretical account that simulates the spread of HIV via sexual transmittal through a little stray human population. The theoretical account examines the emergent effects of different facets of sexual behavior in a population.
2.4 Alternate attacks to the survey of epidemics
2.4.1 Equation-based mold
The most common, earliest known traditional attack to epidemic mold, equation-based mold day of the months back to 1760 when Daniel Bernouli created a theoretical account ( utilizing not additive differential equations ) , to analyze the consequence of cow-pox vaccination on the spread of little syphilis ( Murray 2001 ) .
In the compartmental mold attack, the persons in a population are classified into compartments depending on their position with respect to the infection under survey. Harmonizing to a paper presented by Kermark and McKendrick ( 1927 ) , the population under survey is divided into three distinguishable categories, viz. : The Susceptible, Infected and Removed, where the succeptibles are healthy persons who can catch the disease, the Infected are persons with the disease and the removed are those persons who have recovered, died or are unable to convey the disease. Naturally, the person goes through the three phases in the order S-I-R, giving rise to what is called the SIR compartmental theoretical account.
Differential equations are so used to track single motion kineticss between sub-populations. Harmonizing to Huang et Al ( 2004 ) , these theoretical accounts are suited for imitating infective disease transmittal kineticss, but since they categorize persons in footings of populations, they frequently fail to see societal phenomena associated with human interactions. The basic SIR theoretical account is represented by a non additive system of three equations ( Murray, 2001 ) .
2.4.2 Cellular Automata theoretical accounts
Cellular zombis are a manner to analyze complex systems. A cellular zombi, harmonizing to Schut ( 2007 ) is an array of identically programmed zombi, or cells that interact with each other in a vicinity and have a definite province.
Cellular zombi theoretical accounts have been used by research workers to analyze dynamic and non equilibrium systems and to research epidemic infection and transmittal in animate beings, workss and animate beings ( Huang et al, 2004 ) . They are used to place local bunch and societal features like spatial property, heterogeneousness and interactivity because of their ability to supply intuitive web theoretical accounts.
3. Research Problem
Taking into history the fact that Ebola is a extremely infective disease ( CDC, 2002 ) , there is need to understand how this epidemic occurs in society. One of the most demanding undertakings confronting public wellness practitioners/epidemiologists is the sensing and probe of an epidemic eruption. ( Agung et al 2008 ) . A potpourri of ethical considerations, limited resources ( clip and money ) and hazards involved make it practically prohibitory to carry on investigation/ research lab surveies of the spread of an infective disease throughout a population in existent universe conditions. Additionally, mathematical mold though an alternate, poses a great challenge to many an epidemiologist ( Marchi, 2008 ) , who turn out be “ math phobic ” .
Agent based computing machine simulation and patterning nevertheless comes in ready to hand in the anticipation of the spread and impact of a disease.
3.1 Research inquiries
This survey will seek replies to the undermentioned inquiries:
- Can Agent Based computing machine patterning avert the Ebola epidemic?
- What engineerings are being employed in the direction of the Ebola epidemic?
The theoretical account will besides supply an penetration into why the epidemic might hold failed to distribute to neighboring communities and why it impacted so badly on Bundibugyo territory.
3.2 Research Aim and Aims
To develop an Agent Based Computer theoretical account, with the purpose of imitating the spread of the Ebola epidemic.
3.2.2 Specific aims
- Undertake a instance survey based field enquiry into the spread of the Ebola epidemic with the purpose of easing the mold and simulation the eruption.
- To develop an agent based computing machine theoretical account that will be used to imitate the Ebola epidemic.
- Test the theoretical account.
4. Research Approach
The survey will do usage of instance survey research and Agent based Modeling. Data from interviews and reviewed paperss will be used to imitate the spread of the Ebola virus. Case study research involves an in depth scrutiny of a individual individual or a few people with the purpose of supplying an accurate and complete description of the instance ( Marczyk et al, 2005 ) . Case surveies attempt to convey the niceties of the instance including specific contexts, immaterial influences and particular distinctive inside informations.
Ethnographic informations from the Bundibugyo community will be used to make a landscape, people and regulations for behaviour of the people through computing machine simulation.
The research worker will do usage of Net Logo© 4.0.4 mold and simulation environment to build the theoretical account and run the simulations. Net Logo© is a freeware Agent Based Modeling and simulation tool kit for imitating natural and societal phenomena.
The NetLogo toolkit will be used in the design and building since it provides a model for building a theoretical account and running a simulation, roll uping informations and exposing the consequences.
4.1 Conceptual design
First, a ocular representation of the Bundibugyo Township will be modeled. This will include the countries where the epidemic prevailed.
Another ocular theoretical account will be drawn to portray the behavior of the epidemic in the community.
Using these theoretical accounts the basic features of the community will be determined for simulation.
( The features of the community required for simulation are the population and the chance of contact between persons ) .
The agents, features and the environment will be programmed utilizing the Net Logo scheduling linguistic communication. The theoretical account will be built in four stages as follows:
4.2.1 Low-level formatting
This will imply constructing the button agents and randomly puting them on the show.
4.2.2 Incorporating Behaviour
The process that ties a brace of buttons together, unifying their two sets of buttons will be built.
4.2.3 Incorporating Control
Next the Graphical User Interface ( GUI ) elements that control the apparatus and executing of the simulation will be built. In this stage controls and input parametric quantities will be incorporated.
4.2.4 Data stage
In this stage, the GUI elements that show the informations gathered by the simulation will be built. Here graphical informations end products will be incorporated into the system.
The theoretical account will so be tested utilizing the information collected to see what the result of the simulations will be.
This research intends to develop a tool for epidemiology research workers to utilize as a practical environment research lab to bring out the dynamic behavior of the Ebola epidemic as a consequence of the interactions among single agents. The agent based epidemic theoretical account will imitate the kineticss of the Ebola epidemic that ravaged the people of Bundibugyo territory between November 2007 and February 2008. It is hoped that the consequences of this survey will supply epidemiologists with the chance to detect and research human interactions in the fake epidemic that will enable them to analyse the eruption and spread of this disease.
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