?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F242%2F&rft.title=Overcoming+data+sparsity&rft.creator=Apple%2C+Rosemary&rft.creator=Cawthorn%2C+Chris&rft.creator=Yee+Chan%2C+Kwan&rft.creator=Lachish%2C+Oded&rft.creator=Nonnenmacker%2C+Achim&rft.creator=Porter%2C+Mason+A.&rft.creator=Reboux%2C+Sylvain&rft.creator=Hazelwood%2C+Vera&rft.subject=None%2FOther&rft.subject=Information+and+communication+technology&rft.description=Unilever+is+currently+designing+and+testing+recommendation+algorithms+that+would+make+recommendations+about+products+to+online+customers+given+the+customer+ID+and+the+current+content+of+their+basket.+Unilever+collected+a+large+amount+of+purchasing+data+that+demonstrates+that+most+of+the+items+(around+80%25)+are+purchased+infrequently+and+account+for+20%25+of+the+data+while+frequently+purchased+items+account+for+80%25+of+the+data.+Therefore%2C+the+data+is+sparse%2C+skewed+and+demonstrates+a+long+tail.+Attempts+to+incorporate+the+data+from+the+long+tail%2C+so+far+have+proved+difficult+and+current+Unilever+recommendation+systems+do+not+incorporate+the+information+about+infrequently+purchased+items.+At+the+same+time%2C+these+items+are+more+indicative+of+customers'+preferences+and+Unilever+would+like+to+make+recommendations+from%2Fabout+these+items%2C+i.e.+give+a+rank+ordering+of+available+products+in+real+time.%0D%0A%0D%0AStudy+Group+suggested+to+use+the+approach+of+bipartite+networks+to+construct+a+similarity+matrix+that+would+allow+the+recommendation+scores+for+different+products+to+be+computed.+Given+a+current+basket+and+a+customer+ID%2C+this+approach+gives+recommendation+scores+for+each+available+item+and+recommends+the+item+with+the+highest+score+that+is+not+already+in+the+basket.+The+similarity+matrix+can+be+computed+offline%2C+while+recommendation+score+calculations+can+be+performed+live.+This+report+contains+the+summary+of+Study+Group+findings+together+with+the+insights+into+properties+of+the+similarity+matrix+and+other+related+issues%2C+such+as+recommendation+for+the+data+collection.&rft.date=2008&rft.type=Study+Group+Report&rft.type=NonPeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F242%2F1%2FUnilever_OvercomingDataSparsity.pdf&rft.identifier=++Apple%2C+Rosemary+and+Cawthorn%2C+Chris+and+Yee+Chan%2C+Kwan+and+Lachish%2C+Oded+and+Nonnenmacker%2C+Achim+and+Porter%2C+Mason+A.+and+Reboux%2C+Sylvain+and+Hazelwood%2C+Vera++(2008)+Overcoming+data+sparsity.++%5BStudy+Group+Report%5D+++++