Moa and the multi-model architecture: a new perspective on XNF2

Advanced non-traditional application domains such as geographic information systems and digital library systems demand advanced data management support. In an effort to cope with this demand, we present the concept of a novel multi-model DBMS architecture which provides evaluation of queries on complexly structured data without sacrificing efficiency. A vital role in this architecture is played by the Moa language featuring a nested relational data model based on XNF2, in which we placed renewed interest. Furthermore, extensibility in Moa avoids optimization obstacles due to black-box treatment of ADTs. The combination of a mapping of queries on complexly structured data to an efficient physical algebra expression via a nested relational algebra, extensibility open to optimization, and the consequently better integration of domain-specific algorithms, makes that the Moa system can efficiently and effectively handle complex queries from non-traditional application domains

Content And Multimedia Database Management Systems

A database management system is a general-purpose software system that facilitates the processes of defining, constructing, and manipulating databases for various applications. The main characteristic of the ‘database approach’ is that it increases the value of data by its emphasis on data independence. DBMSs, and in particular those based on the relational data model, have been very successful at the management of administrative data in the business domain. This thesis has investigated data management in multimedia digital libraries, and its implications on the design of database management systems. The main problem of multimedia data management is providing access to the stored objects. The content structure of administrative data is easily represented in alphanumeric values. Thus, database technology has primarily focused on handling the objects’ logical structure. In the case of multimedia data, representation of content is far from trivial though, and not supported by current database management systems

An Egocentric Spatial Data Model for Intelligent Mobile Geographic Information Systems

Individuals in unknown locations, such as utility workers in the field, soldiers on a mission, or sightseeing tourists, share the need for an answer to two basic questions: Where am I? and What is in front of me?Because such information is not readily available in foreign locations, aids in the form of paper maps or mobile GISs, which give individuals an all-inclusive view of the environment, are often used. This panoptic view may hinder the positioning and orienteering process, since people perceive their surroundings perspectively from their current position. In this thesis, I describe a novel framework that resolves this problem by applying sensors that gather the individual\u27s spatial frame of reference. This spatial frame of reference, in combination with an egocentric spatial data model enables an injective mapping between the real world and the data frame of reference, hence, alleviating the individual\u27s cognitive workload. Furthermore, our egocentric spatial data model allows intelligent mobile Geographic Information Systems to capture the notions of here and there, and, consequently, provides insight into the individual\u27s surroundings. Finally, our framework, in conjunction with the context given by the task to be performed, enables intelligent mobile Geographic Information Systems to implicitly answer questions with respect to where, what, and how

A comparative study of structured and un-structured remote data access in distributed computing systems

Recently, the use of distributed computing systems has been growing rapidly due to the result of cheap and advanced microelectronic technology. In addition to the decrease in hardware costs, the tremendous development in machine to machine communication interfaces, especially in local area networking, also favours the use of distributed systems. Distributed systems often require remote access to data stored at different sites. Generally, two models of access to remote data storage exist: the un structured and structured models. In the former, data is simply stored as row of bytes, whereas in the latter, data is stored along with the associated access codes. The objective of this thesis is to compare these two models and hence determines the tradeoffs of each model. First of all, an extended review of the field of distributed data access is provided which addressing key issues such as the basic design principles of distributed computing systems, the notions of abstract data types, data inheritance, data type system and data persistence. Secondly, a distributed system is implemented using the persistent programming language PS-algol and the high level language C in conjunction with the remote procedure call facilities available in Unix(^1) 4.2 BSD operating system. This distributed system makes extensive use of Unix's software tools and hence it is called DCSUNIX for Distributed Computing System on UNIX. Thirdly, two specific applications which employ the implemented system will be given so that a comparison can be made between the two remote data access models mentioned above. Finally, the implemented system is compared with the criteria established earlier in the thesis. keywords: abstract data types, class, database management, data persistence, information hiding, inheritance, object oriented programming, programming languages, remote procedure calls, transparency, and type checking

Moa and the Multi-model architecture: a new perspective on XNF 2

Advanced non-traditional application domains such as geographic information systems and digital library systems demand advanced data management support. In an effort to cope with this demand, we present the concept of a novel multi-model DBMS architecture which provides evaluation of queries on complexly structured data without sacrificing efficiency. A vital role in this architecture is played by the Moa language featuring a nested relational data model based on XNF2 , in which we placed renewed interest. Furthermore, extensibility in Moa avoids optimization obstacles due to black-box treatment of ADTs. The combination of a mapping of queries on complexly structured data to an efficient physical algebra expression via a nested relational algebra, extensibility open to optimization, and the consequently better integration of domain-specific algorithms, makes that the Moa system can efficiently handle complex queries from non-traditional application domains

Database Optimization Aspects for Information Retrieval

There is a growing need for systems that can process queries, combining both structured data and text. One way to provide such functionality is to integrate information retrieval (IR) techniques in a database management system (DBMS). However, both IR and database research have been separate research fields for decades, resulting in different - even conflicting - approaches to data management. Each DBMS has a component called a "query optimizer", which plays a crucial role in the efficiency and flexibility of the system. So, for successful integration the IR techniques and data structures, as well as the DBMS query optimizer, should be adapted to enable mutual cooperation. The author concentrates on top-N queries - a common class of IR queries. An IR top-N query asks for the N best documents given a set of keywords. The author proposes processing the data in batches as a compromise between IR and DBMS query processing. Experiments with this technique show that porting IR optimization techniques is (still) not a promising option due to the additional administrative overhead. Two new mathematical models are introduced to eliminate this overhead: a model that predicts selectivity, which is a crucial factor in the execution costs, and a model that predicts the quality of the top-N

Database independent Migration of Objects into an Object-Relational Database

This paper reports on the CERN-based WISDOM project which is studying the serialisation and deserialisation of data to/from an object database (objectivity) and ORACLE 9i.Comment: 26 pages, 18 figures; CMS CERN Conference Report cr02_01

Developing a Pedestrian Route Network Service (PRNS)

Route network service is becoming increasingly popular. However, although there are significant amount of route network services there are still limitations especially to pedestrian network services. Pedestrians daily make decision about their navigation choices. Developing a pedestrian route network service (PRNS) involves several factors. During this study the analysis of several routing network services have demonstrated that the geographical data is one of the most important factors in order to develop an own PRNS. Considering the idea of estimation two different datasets for the PRNS were evaluated OpenStreetMap (OSM) and Swedish national road database (NVDB). The use of the OSM dataset for developing the PRNS was made after the comparison between both the dataset. OSM has shown more advantages in terms of completeness of route for pedestrian navigation than NVDB. The OSM dataset was created and stored in the PostGIS database. The implementation of own pedestrian network service is intended to facilitate the developments of new PRNS and analysis and comparison of others existing PRNS. The calculation and collection of the routes to be displayed for the user are performed by extended tools within PostGIS such as pgRouting and PostgreSQL respectively. The dataset’s network topology is related to the distance and determination of route choice by the pedestrian. Thus, Geographical Information System (GIS) is also one fundamental factor used in this study to evaluate and create results. The application was implemented in the city of Lund. One of the limitations developing the PRNS is the lack of documentation for new functions which are released by pgRouting developers. Although OSM provides an essential network for developing the PRNS, some closed residential areas, parks, and open areas are not include on the network limiting the PRNS application. In conclusion the PRNS is a useful application in order to assist pedestrians on their wayfinding in the city of Lund. It is also intended to help further development of new PRNS such as mobile PRNS applications. However, the PRNS must be improved and the dataset network requires updating and expansion for successful operations of the PRNS applications.Navigeringstjänster blir allt mer populära, men även om det finns en betydande mängd tjänster, finns det fortfarande begränsningar, speciellt för fotgängare. Fotgängare gör dagligen flera val om hur de ska hitta den bästa vägen i sin närmiljö. Att utveckla en navigeringstjänst för gående (PRNS) involverar flera viktiga faktorer. I denna studie analyseras flera befintliga nättjänster och studien visar att geografiska data är en av de viktigaste faktorerna för att utveckla egna PRNS. Två olika datamängder för PRNS utvärderades: OpenStreetMap (OSM) och svenska nationella vägdatabasen (NVDB). Efter en första utvärdering av de två datamängderna valdes OSM som visade sig ha flera fördelar för en fotgängares navigering. Implementeringen av en egen navigeringstjänst för gående är avsedd att underlätta utvecklingen av nya PRNS och analysering och jämförelsen av andra befintliga PRNS. pqRouting och PostgreSQL beräknar och samlar in de rutter som ska användas, med hjälp av datamängden som finns i databasen PostGIS. Topologin för nätverket i datamängden är relaterat till avstånden och fotgängaren bestämmer vägvalet. Geografiska informationssystem (GIS) är också en grundläggande faktor som används i den här studien för att analysera resultatet. PRNS implementerades i staden Lund och syftet är att underlätta för fotgängare att navigera i staden. En av begränsningarna vid utvecklandet av PRNS är bristen på dokumentation av vissa nya funktionaliteter i pgRouting. Även om OSM tillhandahåller ett grundläggande nätverk av vägar för utvecklingen av PRNS, så saknas information om vissa bostadsområden, parker och allmänna utrymmen, vilket begränsar PRNS. Sammanfattningsvis så är PRNS ett användbart program för att hjälpa fotgängare att välja väg i staden Lund. Vidare utveckling av PRNS kan exempelvis vara en mobilapplikation. Då måste dock PRNS förbättras och datamängden kräver uppdatering och utveckling för att bli framgångsrik.Internet based applications for finding shortest ways to travel are becoming increasingly popular. However, although there are significant amount of these applications there are still limitations especially for pedestrian. Developing an internet based application service for pedestrian involves several steps. During this study the analysis of several internet based applications service for pedestrian have demonstrated that the geographical data is one of the most important components in order to develop the PRNS. Two different dataset were evaluated OpenStreetMap (OSM) and Swedish national road database (NVDB). The use of the OSM dataset for developing the PRNS was made after the comparison between both the dataset. OSM has shown more advantages in terms of completeness of roads network and ways for pedestrian than NVDB. The OSM dataset was created and stored in a database called PostGIS. The calculation of distances and collection of the shortest ways to be displayed for the user are performed by extended tools and programs within PostGIS such as pgRouting and PostgreSQL respectively. The distance and determination of the shortest ways to walk is based on the structure of the dataset and the user choice. Thus, application such as Geographical Information System (GIS) is also one fundamental component used in this study, for example, to evaluate and create maps for visual analysis. One of the limitations developing the PRNS is the lack of documentation for new functions which are released by developers. Some closed residential areas, parks, and open areas are not included on the network limiting the PRNS application. In conclusion the PRNS is a useful application in order to assist pedestrians on their wayfinding in the city of Lund. It is also intended to help further development of new PRNS such as mobile PRNS applications. However, the PRNS must be improved and the dataset network requires updating and expansion for successful operations of the PRNS applications