Do sự vận động không ngừng của thế giới vật chất từ vi mô đến vĩ mô (và kể cả trong ý thức, nhận thức) mà trạng thái và vị trí (xét theo quan điểm động lực học) của các vật không ngừng thay đổi, biến đổi. | IMPLEMENTATION OF THE STDM 95 that belong to a historical view. Further development work would be required to handle historical views fully within the system. The prototype implementation has also indicated possible improvements in the STdM The STDM captures the essential semantics space-time paths events and states of an application and through this model the user sees their problem domain composed of objects and the classes to which they belong. Classes and their relationships may be further refined and some classes may be added or deleted. The integration of time geography and object orientation within a GIS has proven to be a dynamic modelling activity in which the schema is constantly being upgraded. The constraints in the STDM are simple. They are methods attached to the instances of each class. This could be improved by associating knowledge-based rules with events and states of the STDM. For example when event if condition then action. CHAPTER SEVEN Emerging technologies This chapter considers four emerging research topics related to geographical information sciences. They are some of the latest developments in the research fields of databases geographic visualisation and distributed systems. Each section begins with a brief description of the research area then examines its impact on designing spatio-temporal data models in GIS. SPATIO-TEMPORAL OBJECTS IN DATABASE SYSTEMS Despite having interrelated aims research in temporal and spatial database models has predominantly developed independently. Research in temporal database design Al-Taha Snodgrass and Soo 1994 Snodgrass Al-Taha and Soo 1993 Tansel et al. 1993 Soo 1991 has addressed issues related to version management aspects time stamping concurrency control update processing as well as enhancements required for the logical components schema evolution temporal query language syntax and the physical structure storage structure access methods query optimisation query language features . Spatial .
