WebNIR

Server documentation

Dielectric properties of body tissues in the frequency range 10 Hz - 100 GHz: the Tissue Properties Dæmon (tpd).

Overview

The server program is a standard UNIX dæmon named Tissue Properties Dæmon (tpd in the following). tpd manages the table of the 14 parameters for each of the defined tissues and incorporates the procedures for the calculation of the relative permittivity, the electrical conductivity and other related quantities (the loss tangent, the wavelength and the penetration depth).

tpd is a multitasking application developed according to the standard model for UNIX concurrent TCP/IP dæmons. It runs on the Unix system having Internet address niremf.ifac.cnr.it, where it keeps listening to TCP port 5210 for requests from clients.

The client-server dialog is based on a simple ASCII protocol, consisting in text lines terminated by the carriage return + line feed sequence and organized in a command/response iterative process. You can test your link to the server issuing the following command on your system:

telnet niremf.ifac.cnr.it 5210

If the request is detected, tpd will initiate the dialog replying with the following standard positive message:

+OK Tissue Dielectric Properties Server

and then will dispose itself to accept and execute your commands. From this point on, the dialog goes on with the client sending commands to the server and the server executing the commands and answering with data lines and answers, as described below. The dialog is terminated by the client issuing the QUIT command, causing the server to reply with:

+OK Connection closed

and shut down the connection.

Server responses

Every response begins with one of three markers. A positive response starts with +OK, an error with -ERR, and a response that is followed by data lines with +RDY n, where n is the number of lines that follow. After those lines the server sends its standard positive message again, so that a client always knows when a block is over.

Command reference

In the syntax column, angular brackets mark a mandatory parameter and square brackets an optional one. Commands are case insensitive.

Output formats

Four output formats are available, numbered 0 to 3, selected with FORM and written below in the style of the C printf function format string; each comes with a worked example of the whole dialogue. The parameters to pass to the format string are, in order (the expected unit of measurement in brackets):

1. Length of the tissue-name string (i.e. length of the next parameter)
2. Name of the tissue
3. Frequency (Hz)
4. Conductivity (S/m)
5. Relative permittivity
6. Loss tangent
7. Wavelength in tissue (m)
8. Penetration depth in tissue (m)

FORM 0
+OK 0 Tissue Dielectric Properties Server
GETS MUSCLE 1000000
Muscle              f=   1.0000e+06 Hz  sig=   5.0268e-01 S/m  eps=   1.8364e+03  tgl=   4.9204e+00  wav=   4.0320e+00 m  dep=   7.8524e-01 m
+OK Tissue Dielectric Properties Server

FORM 1
+OK 1 Tissue Dielectric Properties Server
GETS MUSCLE 1000000
Muscle                1.0000e+06    5.0268e-01    1.8364e+03    4.9204e+00    4.0320e+00    7.8524e-01
+OK Tissue Dielectric Properties Server

FORM 2
+OK 2 Tissue Dielectric Properties Server
GETS MUSCLE 1000000
Muscle              f=   1.0000e+06 Hz  sig=   5.0268e-01 S/m  eps=   1.8364e+03
+OK Tissue Dielectric Properties Server

FORM 3
+OK 3 Tissue Dielectric Properties Server
GETS MUSCLE 1000000
Muscle                1.0000e+06    5.0268e-01    1.8364e+03
+OK Tissue Dielectric Properties Server

Usage logging and personal data

Every connection to the server is recorded: date and time, the IP address of the client, its reverse DNS name, the country derived from them and the number of commands received. The web application records the same information when a calculation is run; merely opening the page is not recorded. Nothing else is stored: not the commands, not the tissues or the frequencies requested. IFAC-CNR keeps these records for one purpose, to know that the service is still in use and by which communities, since it is offered free of charge and maintained on public funds.

IP address and host name are personal data. They are kept in full for 12 months; after that they are automatically reduced to the network (the first three octets of an IPv4 address, the /48 prefix of an IPv6 address) and to the registered domain of the host name (for example tuhh.de or ic.ac.uk), which can no longer be traced to a person. The records are accessible only to the service administrators and are never shared with third parties. The log of the previous server (2001–2026) has been imported in this anonymised form only. For any question or request concerning these data please contact IFAC-CNR through the contact details of this site.

IFAC-CNR, Florence (Italy), 1997-2024. Documentation by Daniele Andreuccetti.

Keywords: tpd, Tissue Properties Daemon, TCP, 5210, Server documentation, Protocol