{"type":"ScholarlyArticle","title":"A Motion Closed World Asumption","authors":[{"name":"Fusun Yaman","slug":"fusun-yaman","given":"Fusun","family":"Yaman","affiliation":""},{"name":"Dana S. Nau","slug":"dana-s-nau","given":"Dana S.","family":"Nau","affiliation":""},{"name":"V. S. Subrahmanian","slug":"v-s-subrahmanian","given":"V. S.","family":"Subrahmanian","affiliation":""}],"abstract":"Yaman et. al. [Yaman et al., 2004] introduce “go theories” to reason about moving objects. In this paper, we show that this logic often does not allow us to infer that an object is not present at a given place or region, even though common sense would dictate that this is a reasonable inference to make. We define a class of models of go-theories called coherent models. We use this concept to define a motion closed world assumption (MCWA) and develop a notion of MCWA-entailment. We show that checking if a go-theory has a coherent model is NP-complete. An in atom checks if a given object is present in a given region sometime in a given time interval. We provide sound and complete algorithms to check if a ground in literal (positive or negative in atom) can be inferred from a gotheory using the MCWA. In our experiments our algorithms answer such queries in less than 1 second when there are up to 1,000 go-atoms per object.","doi":null,"url":"https://ijcai.org/proceedings/2005/147","pdf":"https://ijcai.org/proceedings/2005/0147.pdf","markdown":"https://ijcai.org/proceedings/2005/147.md","bibtex":"https://ijcai.org/proceedings/2005/bibtex/147","volume":{"slug":"2005","title":"Proceedings of the Nineteenth International Joint Conference on Artificial Intelligence","short_title":"IJCAI 2005","url":"https://ijcai.org/proceedings/2005/","year":2005,"location":"Edinburgh, Scotland, UK","dates":"","editors":"","isbn":"","publisher":"International Joint Conferences on Artificial Intelligence","doi_prefix":""},"section":null,"track":"","number":147,"pages":{"first":621,"last":625},"keywords":[],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}