Cutlery mustard spoon and lettuce fork. Steel was always used for more utilitarian knives, and pewter was used for some cheaper items, especially spoons. From the nineteenth century, electroplated nickel silver (EPNS) was used as a cheaper substitute for sterling silver. In 1913, the British metallurgist Harry Brearley discovered stainless steel by chance and this metal has come to be the predominant one used in cutlery. An alternative is melchior, corrosion-resistant nickel and copper alloy, which can also sometimes contain manganese and nickel-iron. Plastic cutlery is made for disposable use, and is frequently used outdoors for camping, excursions, and barbecues for
Item-item collaborative filtering Item-item collaborative filtering Item-item collaborative filtering, or item-based, or item-to-item, is a form of collaborative filtering for recommender systems based on the similarity between items calculated using people's ratings of those items. Item-item collaborative filtering was invented and used by Amazon.com in 1998. It was first published in an academic conference in 2001. The authors of that paper, Badrul Sarwar, George Karypis, Joseph Konstan, and John Riedl, won the 2016 "Test of Time Award" for their paper "Item-based collaborative filtering recommendation algorithms". The International World Wide Web Conference committee stated that "this outstanding paper has had a considerable real-world impact".