Papers by Markus Schneider
Proceedings of the 8th ACM international symposium on Advances in geographic information systems, 2000
Uncertainty management for geometric data is currently an important problem for (extensible) data... more Uncertainty management for geometric data is currently an important problem for (extensible) databases in general and for spatial databases, image databases, and GIS in particular. In these systems, spatial data are traditionally kept as determinate and sharply bounded objects; the aspect of spatial vagueness is not and cannot he treated by these systems. However, in many geometric and geographical database applications there is a need to model spatial phenomena rather through vague concepts due to indeterminate and blurred boundaries. Following previous work, we first describe a data model for fuzzy spatial objects including data types for fuzzy regions and fuzzy lines. We then, in particular, study the important class of metric operations on these objects.
Advances in Spatial Databases, 1999
In many geographical applications there is a need to model spatial phenomena not simply by sharpl... more In many geographical applications there is a need to model spatial phenomena not simply by sharply bounded objects but rather through vague concepts due to indeterminate boundaries. Spatial database systems and geographical information systems are currently not able to deal with this kind of data. In order to support these applications, for an important kind of vagueness called fuzziness, we propose an abstract, conceptual model of so-called fuzzy spatial data types (i.e., a fuzzy spatial algebra) introducing fuzzy points, fuzzy lines, and fuzzy regions. This paper ? focuses on de ning their structure and semantics. The formal framework is based on fuzzy set theory and fuzzy topology.
Lecture Notes in Computer Science, 2010
New emerging applications including genomic, multimedia, and geospatial technologies have necessi... more New emerging applications including genomic, multimedia, and geospatial technologies have necessitated the handling of complex application objects that are highly structured, large, and of variable length. Currently, such objects are handled using filesystem formats like HDF and NetCDF as well as the XML and BLOB data types in databases. However, some of these approaches are very application specific and do not provide proper levels of data abstraction for the users. Others do not support random updates or cannot manage large volumes of structured data and provide their associated operations. In this paper, we propose a novel two-step solution to manage and query application objects within databases. First, we present a generalized conceptual framework to capture and validate the structure of application objects by means of a type structure specification. Second, we introduce a novel data type called Intelligent Binary Large Object (iBLOB) that leverages the traditional BLOB type in databases, preserves the structure of application objects, and provides smart query and update capabilities. The iBLOB framework generates a type structure specific application programming interface (API) that allows applications to easily access the components of complex application objects. This greatly simplifies the ease with which new type systems can be implemented inside traditional DBMS.
Lecture Notes in Computer Science, 2011
Data warehouses and OLAP systems help to analyze complex multidimensional data and provide decisi... more Data warehouses and OLAP systems help to analyze complex multidimensional data and provide decision support. With the availability of large amounts of spatial data in recent years, several new models have been proposed to enable the integration of spatial data in data warehouses and to help analyze such data. This is often achieved by a combination of GIS and spatial analysis tools with OLAP and database systems, with the primary goal of supporting spatial analysis dimensions, spatial measures and spatial aggregation operations. However, this poses several new challenges related to spatial data modeling in a multidimensional context, such as the need for new spatial aggregation operations and ensuring consistent and valid results. In this paper, we review the existing modeling strategies for spatial data warehouses and SOLAP in all three levels: conceptual, logical and implementation. While studying these models, we gather the most essential requirements for handling spatial data in data warehouses and use insights from spatial databases to provide a "meta-framework" for modeling spatial data warehouses. This strategy keeps the user as the focal point and achieves a clear abstraction of the data for all stakeholders in the system. Our goal is to make analysis more user-friendly and pave the way for a clear conceptual model that defines new multidimensional abstract data types (ADTs) and operations to support spatial data in data warehouses.
Lecture Notes in Computer Science
The notion of a map is a fundamental metaphor in spatial disciplines. However, there currently ex... more The notion of a map is a fundamental metaphor in spatial disciplines. However, there currently exist no adequate data models for maps that define a precise spatial data type for map geometries for use in spatial systems. In this paper, we consider a subclass of map geometries known as spatial partitions that are able to model maps containing region features. However, spatial partitions are defined using concepts such as infinite point sets that cannot be directly represented in computers. We define a graph theoretic model of spatial partitions, called spatial partition graphs, based on discrete concepts that can be directly implemented in spatial systems.
Advances in Spatial Databases, 1993
Spatial data types or algebras for database systems should (i) be fully general (which means, clo... more Spatial data types or algebras for database systems should (i) be fully general (which means, closed under set operations, hence e.g. a region value can be a set of polygons with holes), (ii) have formally defined semantics, (iii) be defined in terms of finite representations available in computers, (iv) offer facilities to enforce geometric consistency of related spatial objects, and (v) be independent of a particular DBMS data model, but cooperate with any. We offer such a definition in two papers. The central idea, introduced in this (first) paper, is to use realms as geometric domains underlying spatial data types. A realm as a general database concept is a finite, dynamic, user-defined structure underlying one or more system data types. A geometric realm defined here is a planar graph over a finite resolution grid. Problems of numerical robustness and topological correctness are solved below and within the realm layer so that spatial algebras defined above a realm enjoy very nice algebraic properties. Realms also interact with a DBMS to enforce geometric consistency on object creation or update.
Lecture Notes in Computer Science, 2001
Proceedings of the 2005 ACM symposium on Applied computing, 2005
Many geographical applications deal with spatial objects that cannot be adequately described by d... more Many geographical applications deal with spatial objects that cannot be adequately described by determinate, crisp concepts because of their intrinsically indeterminate and vague nature. GIS and spatial database systems are currently unable to handle this kind of data. Based on recent work on vague spatial data types, which are part of a formal data model called VASA (Vague Spatial Algebra) and which leverage exact models of crisp spatial data types, this paper introduces a general mechanism for identifying topological predicates for vague spatial objects by means of topological predicates for crisp spatial objects. We illustrate this mechanism by deducing these predicates for vague points.
Lecture Notes in Computer Science, 1999
We define a formal model of spatio-temporal partitions which can be used to model temporally chan... more We define a formal model of spatio-temporal partitions which can be used to model temporally changing maps. We investigate new applications and generalizations of operations that are well-known for static spatial maps. We then define a small set of operations on spatio-temporal partitions that are powerful enough to express all these tasks and more. Spatio-temporal partitions combine the general notion of temporal objects and the powerful spatial partition abstraction into a new, highly expressive spatio-temporal data modeling tool.
Lecture Notes in Computer Science, 1995
The ROSE algebra, defined earlier, is a system of spatial data types for use in spatial database ... more The ROSE algebra, defined earlier, is a system of spatial data types for use in spatial database systems. It offers data types to represent points, lines, and regions in the plane together with a comprehensive set of operations; semantics of types and operations have been formally defined. Values of these data types have a quite general structure, e.g. an object of type regions may consist of several polygons with holes. All ROSE objects are realm-based which means all points and vertices of objects lie on an integer grid and no two distinct line segments of any two objects intersect in their interior. In this paper we describe the implementation of the ROSE algebra, providing data structures for the types and new realm-based geometric algorithms for the operations. The main techniques used are (parallel) traversal of objects, plane-sweep, and graph algorithms. All algorithms are analyzed with respect to their worst case time and space requirements. Due to the realm properties, these algorithms are relatively simple, efficient, and numerically completely robust. All data structures and algorithms have indeed been implemented in the ROSE system; the Modula-2 source code is freely available from the authors for study or use.
Lecture Notes in Geoinformation and Cartography, 2010
People may have problems in finding their way to destinations in large buildings. This raises a n... more People may have problems in finding their way to destinations in large buildings. This raises a need of designing and constructing indoor navigation systems. However, none of the available indoor navigation models can automatically calculate shortest paths according to the geometric structure of indoor space. The reasons are that those models which use geometric information produce circuitous routes and that those models which do not consider geometric information only provide very coarse routes. This paper proposes a model to construct a way finding indoor network that is based on the geometry of the indoor space and that supports lengthdependent optimal routing.
Lecture Notes in Computer Science, 1997
Proceedings of the 22nd ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems, 2014
Spatial database systems and Geographical Information Systems (GIS) are currently only able to ha... more Spatial database systems and Geographical Information Systems (GIS) are currently only able to handle crisp spatial objects, i.e., objects whose extent, shape, and boundary are precisely determined. However, GIS applications are also interested in managing vague or fuzzy spatial objects. Spatial fuzziness captures the inherent property of many spatial objects in reality that do not have sharp boundaries and interiors or whose boundaries and interiors cannot be precisely determined. While topological relationships have been broadly explored for crisp spatial objects, this is not the case for fuzzy spatial objects. In this paper, we propose a novel model to formally define fuzzy topological predicates for simple and complex fuzzy regions. The model encompasses six fuzzy predicates (overlap, disjoint, inside, contains, equal and meet), wherein here we focus on the fuzzy overlap and the fuzzy disjoint predicates only. For their computation we consider two low-level measures, the degree of membership and the degree of coverage, and map them to high-level fuzzy modifiers and linguistic values respectively that are deployed in spatial queries by end-users.
Lecture Notes in Computer Science, 1997
In many geographical applications there is a need to model spatial phenomena not simply by sharp ... more In many geographical applications there is a need to model spatial phenomena not simply by sharp objects but rather through indeterminate or vague concepts. To support such applications we present a model of vague regions which covers and extends previous approaches. The formal framework is based on a general exact model of spatial data types. On the one hand, this simplifies the definition of the vague model since we can build upon already existing theory of spatial data types. On the other hand, this approach facilitates the migration from exact to vague models. Moreover, exact spatial data types are subsumed as a special case of the presented vague concepts. We present examples and show how they are represented within our framework. We give a formal definition of basic operations and predicates which particularly allow a more fine-grained investigation of spatial situations than in the pure exact case. We also demonstrate the integration of the presented concepts into an SQL-like query language. 1. Concepts for vague points and vague lines are currently not taken into account.
Data & Knowledge Engineering, 2005
Besides domain-specific biological problems, biologists are confronted with many computational pr... more Besides domain-specific biological problems, biologists are confronted with many computational problems. The large amount of varying, heterogeneous, and semi-structured biological data, the increasing complexity of biological applications, methods, and tools afflicted with uncertainty and missing knowledge, as well as the lacking interoperability of available tools necessitate integrative measures to enable biology workflow. In this paper we address these problems in the context of the processing and evaluation of BLAST query results. We present a new tool, called BlastQuest, which relies on database technology and provides sophisticated interactive and Web-enabled query, analysis, and visualization facilities for genomics data. The interface with the Gene Ontology and the KEGG pathway databases decisively foster the biological workflow. Finally, based on our experience with BlastQuest, we briefly sketch a new concept, called Genomics Algebra, for solving genomic data management problems from a broader perspective.
Proceedings of the 2003 CIDR Conference, 2003
The dramatic increase of mostly semi-structured genomic data, their heterogeneity and high variet... more The dramatic increase of mostly semi-structured genomic data, their heterogeneity and high variety, and the increasing complexity of biological applications and methods mean that many and very important challenges in biology are now challenges in computing and here ...
Proceedings of the 19th Int. Conf. on Software Engineering and Data Engineering (SEDE), 2010
New emerging scientific applications in geosciences, sensor and spatio-temporal domains require a... more New emerging scientific applications in geosciences, sensor and spatio-temporal domains require adaptive analysis frameworks that can handle large datasets with multiple dimensions. However, existing conceptual design strategies for multidimensional data using the data warehousing framework are not suitable for users, since they involve complex extensions of traditional database design frameworks like E/R and UML diagrams, or the relational star and snowflake schema. There is a lack of a generalized model that provides ...
Advances in Database Technologies, 1999
Currently, there are strong efforts to integrate spatial and temporal database technology into sp... more Currently, there are strong efforts to integrate spatial and temporal database technology into spatio-temporal database systems. This paper views the topic from a rather fundamental perspective and makes several contributions. First, it reviews existing temporal and spatial data models and presents a completely new approach to temporal data modeling based on the very general notion of temporal object. The definition of temporal objects is centered around the observation that anything that changes over time can be expressed as a function over time. For the modeling of spatial objects the well known concept of spatial data types is employed. As specific subclasses, linear temporal and spatial objects are identified. Second, the paper proposes the database embedding of temporal objects by means of the abstract data type (ADT) approach to the integration of complex objects into databases. Furthermore, we make statements about the expressiveness of different temporal and spatial database embeddings. Third, we consider the combination of temporal and spatial objects into spatio-temporal objects in (relational) databases. We explain various alternatives for spatio-temporal data models and databases and compare their expressiveness. Spatio-temporal objects turn out to be specific instances of temporal objects. * This research was partially supported by the CHOROCHRONOS project, funded by the EU under the Training and Mobility of Researchers Programme, Contract No. ERB FMRX-CT96-0056. 1. It is widely known that spatial databases supporting the ADT approach can represent the same information as those decomposing spatial objects into a set of tuples in flat relations [BS77, Ro87].
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Papers by Markus Schneider