Design of a Vital Sign Protocol Format Using XML and ASN.1

Tele-monitoring of the condition of patients is an essential component of an electronichealthcare (e-health) system. In an electronic health record system, vital signs which reflect the condition of the patient have to be transferred over the heterogeneous communication network. One of the fundamental problems in dealing with communication in heterogeneous systems is to exchange data in such a way that the data received can be interpreted the same ways as the data before transmission. In the OSI model, the representation of data (including data structures and data types) to be exchanged is a function of the application layer [24]. Meanwhile, the encoding of the data format into a specific bytes stream for transfer is addressed by the presentation layer. This separation of functions allows the application layer deal only with the data format, independent of the encoding type applied in Presentation Layer. The aim of this thesis is to investigate the tool-based design methods to construct a protocol data format for distributed applications that apply separation of data format specification at several abstraction levels, distinguishing between abstract syntax formats and distinguishing transfer syntax format which are meaningful for the applications and the underlying transport systems, respectively. The design methods address some features presented by XML-based data format, while to get more compact transfer syntax, the design methods makes use of ASN.1 encoding rules to produce binary-encoded data format. Many electronic health record systems use XML technology as data format in the application layer. One of the benefits of using an XML-based data format is independency from encoding issue applied in its underlying layer. However, considering to the transfer syntax, an XML-based data format consumes more data length. It is because of the encoding technique used by XML-based data format is based-on textual encoding. By applying encoding rules like in ASN.1 in the presentation layer, the electronic health record system may produce a more compact transfer syntax, due to the feature of ASN.1 encoding rules that can generate binaryencoded data format, which is more compact than textual encoding like used by XML. The design methods are then applied to construct a protocol data format specific for electronic health records, including vital signs data of both continuous-time and non continuous-time type. Table of contents III