Large-scale ontology storage and query using graph database-oriented approach: The case of Freebase

Author(s):  
Mahmoud Elbattah ◽  
Mohamed Roushdy ◽  
Mostafa Aref ◽  
Abdel-Badeeh M. Salem
Author(s):  
Martin Hoppen ◽  
Juergen Rossmann ◽  
Michael Schluse ◽  
Ralf Waspe ◽  
Malte Rast

Using object-oriented databases as the primary data source in VR applications has a variety of advantages, but requires the development of new techniques concerning data modeling, data handling and data transfer from a Virtual Reality system’s point of view. The many advantages are outlined in the first part of this paper. We first introduce versioning and collaboration techniques as our main motivation. These can also be used in the traditional file based approach, but are much more powerful when realized with a database on an object and attribute level. Using an object-oriented approach to data modeling, objects of the real world can be modeled more intuitively by defining appropriate classes with their relevant attributes. Furthermore, databases can function as central communication hubs for consistent multi user interaction. Besides, the use of databases with open interface standards allows to easily cooperate with other applications such as modeling tools and other data generators. The second part of this paper focuses on our approach to seamlessly integrate such databases in Virtual Reality systems. For this we developed an object-oriented internal graph database and linked it to object-oriented external databases for central storage and collaboration. Object classes defined by XML data schemata allow to easily integrate new data models in VR applications at run-time. A fully transparent database layer in the simulation system makes it easy to interchange the external database. We present the basic structure of our simulation graph database, as well as the mechanisms which are used to transparently map data and meta-data from the external database to the simulation database. To show the validity and flexibility of our approach selected applications realized with our simulation system so far e. g. applications based on geoinformation databases such as forest inventory systems and city models, applications in the field of distributed control and simulation of assembly lines or database-driven virtual testbeds applications for automatic map generation in planetary landing missions are introduced.


2020 ◽  
pp. 1-62
Author(s):  
Zhe Feng ◽  
Fengfei Song ◽  
Koichi Sakaguchi ◽  
L. Ruby Leung

AbstractA process-oriented approach is developed to evaluate warm-season mesoscale convective system (MCS) precipitation and their favorable large-scale meteorological patterns (FLSMPs) over the U.S. This approach features a novel observation-driven MCS-tracking algorithm using infrared brightness temperature and precipitation feature at 12, 25 and 50 km resolution and metrics to evaluate the model large-scale environment favorable for MCS initiation. The tracking algorithm successfully reproduces the observed MCS statistics from a reference 4-km radar MCS database. To demonstrate the utility of the new methodologies in evaluating MCS in climate simulations with mesoscale resolution, the process-oriented approach is applied to two climate simulations produced by the Variable-Resolution Model for Prediction Across Scales coupled to the Community Atmosphere Model physics, with refined horizontal grid spacing at 50 km and 25 km over North America. With the tracking algorithm applied to simulations and observations at equivalent resolutions, the simulated number of MCS and associated precipitation amount, frequency and intensity are found to be consistently underestimated in the Central U.S., particularly from May to August. The simulated MCS precipitation shows little diurnal variation and lasts too long, while MCS precipitation area is too large and intensity is too weak. The model is able to simulate four types of observed FLSMP associated with frontal systems and low-level jets (LLJ) in spring, but the frequencies are underestimated because of low-level dry bias and weaker LLJ. Precipitation simulated under different FLSMPs peak during daytime, in contrast to the observed nocturnal peak. Implications of these findings for future model development and diagnostics are discussed.


2019 ◽  
pp. 1300-1319
Author(s):  
Moha El-Ayachi

The information on land is a basic resource at the economic, social, and industrial levels. Many approaches have been made to enhance integrating the geospatial technology, enable managing the geospatial features, and provide decision makers with capabilities for best land governance. The goal behind this chapter is to develop an approach dealing with a necessary paradigm of improving land information management. Such approach is made up of a series of the fundamental requirements and principles. The requirements encompass the fundamental geodetic network supporting spatial infrastructure, a series of large-scale maps, an integrated land administration system, and a basic conceptual core model for the land information system. The principles of the new paradigm will be discussed. To achieve such objective, the object oriented approach as an emerging methodology was followed to improve land administration and management.


Author(s):  
Moha El-Ayachi

The information on land is a basic resource at the economic, social, and industrial levels. Many approaches have been made to enhance integrating the geospatial technology, enable managing the geospatial features, and provide decision makers with capabilities for best land governance. The goal behind this chapter is to develop an approach dealing with a necessary paradigm of improving land information management. Such approach is made up of a series of the fundamental requirements and principles. The requirements encompass the fundamental geodetic network supporting spatial infrastructure, a series of large-scale maps, an integrated land administration system, and a basic conceptual core model for the land information system. The principles of the new paradigm will be discussed. To achieve such objective, the object oriented approach as an emerging methodology was followed to improve land administration and management.


1998 ◽  
Vol 179 ◽  
pp. 474-477 ◽  
Author(s):  
G. Greene ◽  
B. McLean ◽  
B. Lasker ◽  
D. Wolfe ◽  
R. Morbidelli ◽  
...  

The original GSC-I (Jenkner et al. 1990) which contains 25 million entries and requires approximately 1GB of storage was at the edge of technological capability at the time catalogue construction began in 1984. At that time, a custom coded database was built since the relational databases of the era were unsuited to the HST-specific access requirements. A second generation GSC is now being constructed (Lasker et al. 1995), with an estimated 10 billion entries and a size of 2 Terabytes. The current generation of object-oriented database (OODB) systems are more suited to the needs of large astronomical catalogues and are being adopted by many large-scale projects. In a joint effort between the Space Telescope Science Institute and Osservatorio Astronomico di Torino, we are currently designing such an OODB for the Guide Star Catalogues and are implementing a prototype using the GSC-I data.


Author(s):  
Maurizio Nolé ◽  
Carlo Sartiani

 In the recent years many real-world applications have been modeled by graph structures (e.g., social networks, mobile phone networks, web graphs, etc.), and many systems have been developed to manage, query, and analyze these datasets. These systems could be divided into specialized graph database systems and large-scale graph analytics systems. The first ones consider end-to-end data management issues including storage representations, transactions, and query languages, whereas the second ones focus on processing specific tasks over large data graphs. In this paper we provide an overview of several  graph database systems and graph processing systems, with the aim of assisting the reader in identifying the best-suited solution for her application scenario.


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