A version management model of PDM system and its realization

Based on the key function of version management in PDM system, this paper discusses the function and the realization of version management and the transitions of version states with a workflow. A directed aeyclic graph is used to describe a version model. Three storage modes of the directed acyelic graph version model in the database, the bumping block and the PDM working memory are presented and the conversion principle of these three modes is given. The study indicates that building a dynamic product structure configuration model based on versions is the key to resolve the problem. Thus a version model of single product object is built. Then the version management model in product structure configuration is built and the application of version management of PDM syster is presented as a case.

Versioned geoscientific workflow for the collaborative geosimulation of human-nature interactions-a case study of global change and human activities

Global change refers to changes in the relationship between humans and nature.It is desirable to actively integrate human social activities into the unified framework of global change so that their mutual relations and functional mechanisms can be understood.This complicated issue necessitates an appropriate method allowing domain experts to collaboratively contribute their knowledge to geoscientific research.Also,an efficient approach to optimize experimentation is of great importance.The reproducibility of research methods and results needs to be improved to boost the sharing of geographic knowledge and resources.This paper proposes a versioned geoscientific workflow and characterizes its full lifecycle using Virtual Geographic Environments,intending to facilitate and improve research related to the interactions between global change and human activities.The geoscientific workflow management is realized using the concept of version management,making geographic simulation methods and computational results easily reproducible and extendable.The sharing and reuse of geographic knowledge in various forms are archived through version management of geoscientific workflows.A versatile prototype system is implemented which enables the visual modeling of geoscientific workflows,the interactive optimization and collaborative evaluation of geoscientific workflows at runtime,the multi-dimensional dynamic visualization of geo-workflow outputs,and role-based access control for data security.

Design and Implementation of an Interoperable Object Platform for Multi-Databases

In this paper, the authors present the design and implementation of an Interoperable Object Platform for Multi-Databases (IOPMD). The aim of the system is to provide a uniform object view and a set of tools for object manipu lation and query based on heterogeneous multiple data sources under client/server environment. The common object model is compatible with ODMG2.0 and OMG'sCORBA, which provides main OO features such as OID, attribute, method, inheri tance, reference, etc. Three types of interfaCes, namely Vface, IOQL and C++ API, are given to provide the database programmer with tools and functionalities for application development. Nested transactions and compensating technology are adopted in transaction manager. In discussing some key 'implementation techlliques, translation and mapping approaches from various schemata to a common object schemaare proposed. Buffer management provides the data caching policy and consistency maintenance of cached data. Version managemellt presellts some operations based on the definitions in semantic version model, and introduces the implemelltation of the semantic version graph.