Spread

Association rules discovered from transaction databases can be large in number. Reduction of association rules is an issue in recent times. Conventionally by varying support and confidence number of rules can be increased and decreased. By combining additional constraint with support number of frequent itemsets can be reduced and it leads to generation of less number of rules. Average inter itemset distance(IID) or Spread, which is the intervening separation of itemsets in the transactions has been used as a measure of interestingness for association rules with a view to reduce the number of association rules. In this paper by using average Inter Itemset Distance a complete algorithm based on the apriori is designed and implemented with a view to reduce the number of frequent itemsets and the association rules and also to find the distribution pattern of the association rules in terms of the number of transactions of non occurrences of the frequent itemsets. Further the apriori algorithm is also implemented and results are compared. The theoretical concepts related to inter itemset distance are also put forward.

Association Rule discovery has been an important problem of investigation in knowledge discovery and data mining. An association rule describes associations among the sets of items which occur together in transactions of databases.The Association Rule mining task consists of finding the frequent itemsets and the rules in the form of conditional implications with respect to some prespecified threshold values of support and confidence.The interestingness of Association Rules are determined by these two measures. However, other measures of interestingness like lift and conviction are also used. But, there occurs an explosive growth of discovered association rules and many of such rules are insignificant. In this paper we introduce a new measure of interestingness called Inter Itemset Distance or Spread and implemented this notion based on the approaches of the apriori algorithm with a view to reduce the number of discovered Association Rules in a meaningful manner. An analysis of the working of the new algorithm is done and the results are presented and compared with the results of conventional apriori algorithm.

Abstract: Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis, is an emerging infectious disease implicated in declines of amphibian populations around the globe. An emerging infectious disease is one that has recently been discovered; has recently increased in incidence, geography, or host range; or is newly evolved. For any given outbreak of an emerging disease, it is therefore possible to state two hypotheses regarding its origin. The novel pathogen hypothesis states that the disease has recently spread into new geographic areas, whereas the endemic pathogen hypothesis suggests that it has been present in the environment but recently has increased in host range or pathogenicity. Distinguishing between these hypotheses is important, because the conservation measures needed to slow or stop the spread of a novel pathogen are likely to differ from those needed to prevent outbreaks of an endemic pathogen. Population genetics may help discriminate among the possible origins of an emerging disease. Current evidence suggests chytridiomycosis may be a novel pathogen being spread worldwide by carriers; until we know how much genetic variation to expect in an endemic strain, however, we cannot yet conclude that B. dendrobatidis is a novel pathogen.Resumen: La quitridiomicosis, causada por el hongo patógeno Batrachochytrium dendrobatidis, es una enfermedad infecciosa emergente implicada en las declinaciones de poblaciones de anfibios en el mundo. Una enfermedad infecciosa emergente es una que ha sido descubierta recientemente; que ha incrementado en su rango de incidencia, geográfico o de huéspedes recientemente; o que ha evolucionado recientemente. Para cualquier brote de una enfermedad emergente es posible enunciar dos hipótesis en relación con su origen. La hipótesis del patógeno incipiente establece que el la enfermedad se ha extendido recientemente hacia áreas geográficas nuevas, mientras que la hipótesis del patógeno endémico sugiere que ha estado presente en el ambiente pero que ha incrementado en el rango de huéspedes o de patogenicidad. Es importante distinguir entre estas dos hipótesis, porque es probable que las medidas de conservación que se requieren para reducir o detener la dispersión de un patógeno incipiente sean diferentes a las requeridas para prevenir brotes de un patógeno endémico. La genética de poblaciones puede ayudar a distinguir entre los posibles orígenes de una enfermedad emergente. La evidencia actual sugiere que la quitridiomicosis puede ser un patógeno incipiente que esta siendo dispersado por transportistas mundialmente; sin embargo, no podemos concluir que B. dendrobatidis es un patógeno incipiente hasta que no se conozca la variación genética esperada en una cepa endémica.Resumen: La quitridiomicosis, causada por el hongo patógeno Batrachochytrium dendrobatidis, es una enfermedad infecciosa emergente implicada en las declinaciones de poblaciones de anfibios en el mundo. Una enfermedad infecciosa emergente es una que ha sido descubierta recientemente; que ha incrementado en su rango de incidencia, geográfico o de huéspedes recientemente; o que ha evolucionado recientemente. Para cualquier brote de una enfermedad emergente es posible enunciar dos hipótesis en relación con su origen. La hipótesis del patógeno incipiente establece que el la enfermedad se ha extendido recientemente hacia áreas geográficas nuevas, mientras que la hipótesis del patógeno endémico sugiere que ha estado presente en el ambiente pero que ha incrementado en el rango de huéspedes o de patogenicidad. Es importante distinguir entre estas dos hipótesis, porque es probable que las medidas de conservación que se requieren para reducir o detener la dispersión de un patógeno incipiente sean diferentes a las requeridas para prevenir brotes de un patógeno endémico. La genética de poblaciones puede ayudar a distinguir entre los posibles orígenes de una enfermedad emergente. La evidencia actual sugiere que la quitridiomicosis puede ser un patógeno incipiente que esta siendo dispersado por transportistas mundialmente; sin embargo, no podemos concluir que B. dendrobatidis es un patógeno incipiente hasta que no se conozca la variación genética esperada en una cepa endémica.