Bhlen, M.H., Jensen, C.S. and Skjellaug, B. (1998) Spatio-Temporal Database Support for Legacy Applications, ACM Symp. on Applied Computing, 226-234.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....features are given by bitemporal elements attached to all components of simplicial complexes. On the other hand, temporal data models have been generalized to become spatio temporal and include variants of Gadia s temporal model (Gadia et al. 1993) which are described in (Cheng et al. 1994, Bhlen et al. 1998). The main drawback of all these approaches is that ultimately they are incapable of modeling continuous changes of spatial objects over time. Our approach to dealing with spatio temporal data takes a more integrated view of space and time and includes the treatment of continuous spatial changes. ....

Bhlen, M.H., Jensen, C.S. and Skjellaug, B. (1998) Spatio-Temporal Database Support for Legacy Applications, ACM Symp. on Applied Computing, 226-234.

....simplicial complexes and whose temporal features are given by bitemporal elements attached to all components of simplicial complexes. On the other hand, temporal data models have been generalized to become spatio temporal and include variants of Gadia s temporal model [19] which are described in [7, 5]. The main drawback of all these approaches is that ultimately they are incapable of modeling continuous changes of spatial objects over time. Our approach to dealing with spatio temporal data takes a more integrated view of space and time and includes the treatment of continuous spatial changes. ....

Böhlen, M.H., Jensen, C.S. & Skjellaug, B.: Spatio-Temporal Database Support for Legacy Applications, ACM Symp. on Applied Computing, 1998, 226-234.

....simplicial complexes and whose temporal features are given by bitemporal elements attached to all components of simplicial complexes. On the other hand, temporal data models have been generalized to become spatio temporal and include variants of Gadia s temporal model [16] which are described in [3, 2]. The main drawback of all these approaches is that they are incapable of modeling continuous changes of spatial objects over time. Another approach which takes a more integrated view of space and time and which will be the basis of this paper introduces the concept of spatio temporal data types ....

M. H. Bohlen, C. S. Jensen, and B. Skjellaug. SpatioTemporal Database Support for Legacy Applications. In ACM Symp. on Applied Computing, pages 226--234, 1998.

.... d1, Division2: d2) from d1 in q2, d2 in q2 where d1 = d2 and is a true(d1 st touch(d2,event( 01 02 1997 ) 5 Related Work As argued before, recent research have devoted more attention to incorporating time into spatial databases (e.g. ATSS93, BVH96, Skj96, CT95, Lan93a, PW94, SB97, BJS97, Cho] but there is relatively few published work on actual implementation of spatio temporal models. We are aware of only two such works [PW94, SB97] The majority of the proposed approaches are focused towards modeling instead of implementation. Careful analysis of some of those proposals ....

....Careful analysis of some of those proposals show them to unfeasible to implement, requiring further modification to the proposed models. Indeed, this was the case with the model upon which we base our implementation [Bot95] Most spatio temporal models have an associated query language (e.g. BJS97, BVH96] Alternatively, our prototype manages spatio temporal data through the definition and implementation of a basic set of classes and operators on a OODB. Steiner and Norrie s [SN97] research also uses such an approach, though dealing only with temporal data. Peuquet and Wentz s work [PW94] ....

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M. Bohlen, C. S. Jensen, and B. Skjellaug. Spatio-Temporal Database Support for Legacy Applications. Technical Report TR-20, TimeCenter, July 1997.

....more temporal aspects of the database entities. It is conceptually straightforward to also associate the database entities with spatial values. Concrete proposals include a variant of Gadia s temporal model [Tansel et al. 1993, Ch. 2] a derivative of this model [Cheng and Gadia 1994] and STSQL [Bohlen et al. 1998]. Essentially, these proposals introduce functions from the product of time and space to base domains, and they provide languages for querying the resulting databases. These proposals are orthogonal to the specifics of types and simply abstractly assume types of arbitrary subsets of space and ....

B ohlen, M. H., Jensen, C. S., and Skjellaug, B. 1998. Spatio-Temporal Database Support for Legacy Applications. In Proceedings of the 1998 ACM Symposium on Applied Computing (Atlanta, Georgia, February 1998), pp. 226--234.

....for capturing one or more temporal aspects of the database entities. It is conceptually straightforward to also associate the database entities with spatial values. Concrete proposals include a variant of Gadia s temporal model [TCG 93, Ch. 2] a derivative of this model [CG94] and STSQL [BJS98] Essentially, these proposals introduce functions from the product of time and space to base domains, and they provide languages for querying the resulting databases. These proposals are orthogonal to the specifics of types and simply abstractly assume types of arbitrary subsets of space and ....

M. H. Bohlen, C. S. Jensen, and B. Skjellaug. Spatio-Temporal Database Support for Legacy Applications. In Proceedings of the 1998 ACM Symposium on Applied Computing, pages 226--234, Atlanta, Georgia, February 1998.

....which, by definition, combines only those operands tuples which have intersecting references to the underlying dimension space. In that sense, and contradictory to the above claim of Gting, there are dimensional selections and dimensional joins, also for spatial ADT extensions, e.g. cf. STSQL ([2]) A comparison framework is given by extending Codd s relational model [5] with a single 1dimensional ADT (i.e. an interval or a line segment ADT) over which four algebras are defined, and where each algebra extends the relational algebra (RA) in a particular way. There are two pure (i.e. ....

....of 2) name dept D Pete d1 [1985 89] Ann d1 [1988 90] Ann d1 [1996 97] Queries 1) and 2) above are dimensional aggregate formation and dimensional difference, respectively. Notice that both results automatically accounts for periodic changes. Now, let the above queries be expressed in STSQL [2] by 1) and 2) below, respectively: 1) REDUCIBLE (D) AS D SELECT dept, SUM(sal) FROM EMP GROUP BY dept; 2) REDUCIBLE (EMP.D, DEPT.D) AS D SELECT name, dept FROM EMP EXCEPT SELECT FROM DEPT; The REDUCIBLE flag, which is a STSQL construct, imposes a dimensional query over the referenced ADT ....

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M. Bhlen, C. S. Jensen, and B. Skjellaug. Spatio-Temporal DataBase Support for Legacy Applications. In Proceedings of the ACM Symposium on Applied Computing, pages 226--234, February/March 1998.

....VALUES (3) SELECT FROM p WHERE NOT EXISTS (SELECT FROM q WHERE q.B = p.A) SELECT FROM v; The first statement extends p to capture valid time by making it a valid time table. Alternatively, valid time could be captured by adding a special valid time column, thus not altering the table type [BJS98]. The other statements are all legacy SQL 92 statements, but their semantics have changed because the underlying data structure, i.e. table p, has changed. For example, the modification statements must adequately maintain the valid time of p [BBJS97] Also, integrity checking must take into ....

M. H. Bohlen, C. S. Jensen, and B. Skjellaug. Spatio-Temporal Database Support for Legacy Applications. In Proceedings of the 1998 ACM Symposium on Applied Computing, Marriott Marquis, Atlanta, Georgia, February, submitted 1998.

....following we show that time could easily exhibit a composite structure, i.e. the temporal support of an application could be de ned by means of combining the built in time dimensions and, thereby, utilize the multitemporal semantics of a model. The spatio temporal extended SQL by B#hlen et al. [3], termed STSQL, incorporates multiple spatial and temporal dimension attributes 1 de ned for a relation. A relation with both spatial and temporal dimension attributes has, logically speaking, a multi dimensional space timestamp associated with each object, i.e. tuple. A space timestamp ....

.... by the TChimera model by Bertino et al. 2] is generalized to a multi dimensional structure that is combined with our approach of object versioning on the attribute level; Fourth, multi dimensional time are applied to both objects and attributes, and not only to objects (i.e. tuples) as by STSQL [3]. Thus, a database designer has, by this approach, the AEexibility of assigning whatever temporal built in or user de ned dimensions required. The temporal model de nes how these notions and concepts are incorporated by two main temporal concepts, termed a quali er temporal(T) and a type TObject, ....

[Article contains additional citation context not shown here]

M. B#hlen, C. S. Jensen, and B. Skjellaug. Spatio-Temporal DataBase Support for Legacy Applications. Technical report, Technical report(TR-20), TimeCenter, July 1997.

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