Data Model Evolution Research Articles

A REVIEW OF 3D SPATIAL DATA MODELS FOR SURFACE AND SUBSURFACE INTEGRATION OF SPATIAL OBJECTS

Abstract. Three dimensional (3D) spatial data models have been known as a geographic information system platform for representing the dimensionality of spatial objects with respect to the real world. They can be used to mimmick the real-world objects above the ground, on the ground and underground. A 3D spatial data model that can integrate surface and subsurface elements will have a significant impact on engineering, spatial and urban planning, and the built environment. Such an impact includes good infrastructure development, proper planning, result-oriented installation of utilities, location-specific excavation of existing utilities, and cost-effective economy resulting from minimal damage of infrastructures. This article explores and documents the state-of-the-art with respect to 3D spatial data models specifically for the integration of surface and subsurface objects based on a thorough review of the literature in academic articles, technical reports, and web-based materials. To better understand the scope, this paper reviews the different 3D spatial modelling approach for surface spatial objects, subsurface spatial objects, and with keen focus on surface and subsurface spatial objects integration. The Open Geospatial Consortium (OGC) has played an important role in data integration and has a core space in 3D spatial data model evolution. One of the recent data models for such task is CityJSON due to its simplicity in data storage, visualization, manipulation, and data update compared to CityGML. The parameters influencing the choice of models can be attributed to the availability of data structure, applicability, exchange format and relevance. Based on the range of 3D spatial data model reviewed, a unified model is expedient for integration of surface and subsurface spatial objects.

A Transformational Approach to Managing Data Model Evolution of Web Services

The communication of web services is typically organized through APIs, which rely on a common data model shared among system components. Over time, this data model must be changed in order to accommodate new or changing requirements, and the components including the data they are operating on must be migrated. In practice however, not all affected components can be migrated instantly and at the same time. A common approach is to plan data model changes in a backward compatible fashion, which causes serious maintenance problems and is a common cause of technical debt. We propose an alternative solution, using a translation layer serving as a round-trip migration service, responsible for the lossless translation of object-oriented data model instances of different versions. We present a framework which offers a version-aware interface definition language (IDL) for APIs, a typed JavaScript-based language using the IDL definition, and a run-time environment. From a methodological point of view, development is supported by a catalog which comprises a set of typical evolution scenarios along with corresponding round-trip migration strategies. We showcase the applicability of our approach via a case study of a real-world e-commerce web application, and evaluate correctness through automated testing.

Handling probabilistic integrity constraints in pay-as-you-go reconciliation of data models

Data models capture the structure and characteristic properties of data entities, e.g., in terms of a database schema or an ontology. They are the backbone of diverse applications, reaching from information integration, through peer-to-peer systems and electronic commerce to social networking. Many of these applications involve models of diverse data sources. Effective utilisation and evolution of data models, therefore, calls for matching techniques that generate correspondences between their elements. Various such matching tools have been developed in the past. Yet, their results are often incomplete or erroneous, and thus need to be reconciled, i.e., validated by an expert. This paper analyses the reconciliation process in the presence of large collections of data models, where the network induced by generated correspondences shall meet consistency expectations in terms of integrity constraints. We specifically focus on how to handle data models that show some internal structure and potentially differ in terms of their assumed level of abstraction. We argue that such a setting calls for a probabilistic model of integrity constraints, for which satisfaction is preferred, but not required. In this work, we present a model for probabilistic constraints that enables reasoning on the correctness of individual correspondences within a network of data models, in order to guide an expert in the validation process. To support pay-as-you-go reconciliation, we also show how to construct a set of high-quality correspondences, even if an expert validates only a subset of all generated correspondences. We demonstrate the efficiency of our techniques for real-world datasets comprising database schemas and ontologies from various application domains.

A scalable model based approach for data model evolution: Application to space missions data models

During the development of a complex system, data models are the key to a successful engineering process, as they contain and organize all the information manipulated by the different functions involved in the design of the system. Moreover, these data models evolve throughout the design, as the development raises issues that have to be solved through a restructuration of data organization. But any such data model evolution has a deep impact on the functions that have already being defined.Recent research tries to deal with this issue by studying how complex industrial data models evolve from one version to another and how their data instances co-evolve. Complexity and scalability issues make this problem a major scientific challenge, leading to huge gains in development efficiency. This problem is of particular interest in the field of aeronautics and space systems. Indeed, the development of these systems produces many complex data models associated to the designed systems and/or to the systems under design, hence on the one hand data models are available. On the other hand, it is well known that these systems are developed in the context of collaborative projects that may last for decades. In such projects, specifications together with the associated data models are bound to evolve and engineering processes shall take into account this evolution.Our work addresses the problem of data model evolution in a model-driven engineering setting. We focus on minimizing the impact of model evolution on the system development processes in the specific context on the space engineering area, where data models may involve thousands of concepts and relationships, and we investigate the performance of the model-based development (MBD) approach we propose for data model evolution over two space missions, namely PHARAO and MICROSCOPE.

A new archival infrastructure for highly-structured astronomical data

With the advent of the 2020 Radio Astronomy Telescopes era, the amount and format of the radioastronomical data is becoming a massive and performance-critical challenge. Such an evolution of data models and data formats require new data archiving techniques that allow massive and fast storage of data that are at the same time also efficiently processed. A useful expertise for efficient archiviation has been obtained through data archiving of Medicina and Noto Radio Telescopes. The presented archival infrastructure named the Radio Archive stores and handles various formats, such as FITS, MBFITS, and VLBI’s XML, which includes description and ancillary files. The modeling and architecture of the archive fulfill all the requirements of both data persistence and easy data discovery and exploitation. The presented archive already complies with the Virtual Observatory directives, therefore future service implementations will also be VO compliant. This article presents the Radio Archive services and tools, from the data acquisition to the end-user data utilization.

Generating database migrations for evolving web applications

WebDSL is a domain-specific language for the implementation of dynamic web applications with a rich data model. It provides developers with object-oriented data modeling concepts but abstracts over implementation details for persisting application data in relational databases. When the underlying data model of an application evolves, persisted application data has to be migrated. While implementing migration at the database level breaks the abstractions provided by WebDSL, an implementation at the data model level requires to intermingle migration with application code. In this paper, we present a domain-specific language for the coupled evolution of data models and application data. It allows to specify data model evolution as a separate concern at the data model level and can be compiled to migration code at the database level. Its linguistic integration with WebDSL enables static checks for evolution validity and correctness.

Explicit state representation and the ATLAS event data model: theory and practice

In anticipation of data taking, ATLAS has undertaken a program of work to develop an explicit state representation of the experiment's complex transient event data model. This effort has provided both an opportunity to consider explicitly the structure, organization, and content of the ATLAS persistent event store before writing tens of petabytes of data (replacing simple streaming, which uses the persistent store as a core dump of transient memory), and a locus for support of event data model evolution, including significant refactoring, beyond the automatic schema evolution capabilities of underlying persistence technologies. ATLAS has encountered the need for such non-trivial schema evolution on several occasions already.This paper describes the state representation strategy (transient/persistent separation) and its implementation, including both the payoffs that ATLAS has seen (significant and sometimes surprising space and performance improvements, the extra layer notwithstanding, and extremely general schema evolution support) and the costs (additional and relatively pervasive additional infrastructure development and maintenance). The paper further discusses how these costs are mitigated, and how ATLAS is able to implement this strategy without losing the ability to take advantage of the (improving!) automatic schema evolution capabilities of underlying technology layers when appropriate.Implications of state representations for direct ROOT browsability, and current strategies for associating physics analysis views with such state representations, are also described.

Defining and validating metrics for assessing the understandability of entity–relationship diagrams

Database and data model evolution cause significant problems in the highly dynamic business environment that we experience these days. To support the rapidly changing data requirements of agile companies, conceptual data models, which constitute the foundation of database design, should be sufficiently flexible to be able to incorporate changes easily and smoothly. In order to understand what factors drive the maintainability of conceptual data models and to improve conceptual modelling processes, we need to be able to assess conceptual data model properties and qualities in an objective and cost-efficient manner. The scarcity of early available and thoroughly validated maintainability measurement instruments motivated us to define a set of metrics for Entity–Relationship (ER) diagrams. In this paper we show that these easily calculated and objective metrics, measuring structural properties of ER diagrams, can be used as indicators of the understandability of the diagrams. Understandability is a key factor in determining maintainability as model modifications must be preceded by a thorough understanding of the model. The validation of the metrics as early understandability indicators opens up the way for an in-depth study of how structural properties determine conceptual data model understandability. It also allows building maintenance-related prediction models that can be used in conceptual data modelling practice.