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An Internet resource for the calculation of the

Dielectric Properties of Body Tissues

in the frequency range 10 Hz - 100 GHz

SERVER DOCUMENTATION
ITALIAN NATIONAL RESEARCH COUNCIL

Institute for Applied Physics

Nello Carrara - Florence (Italy)
red ball Overview
red ball Server responses
red ball Command reference
red ball Output formats

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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 (currently a Linux box) having Internet address niremf.ifac.cnr.it (please use this address, not the corresponding numeric IP, because the latter can change without notice), 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 iniziate 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 up, 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

As previously stated, the client-server dialog is based on a simple, text-oriented command/response protocol. The client sends commands to the server, the server replies with data lines and responses. With very few exceptions, messages from the server fall within one of the five categories described below. In the description, square brackets identify optional parameters, while angular brackets identify mandatory parameters.

Generic positive response
Usually, tpd concludes the execution of a command with the message: +OK Tissue Dielectric Properties Server meaning that the command has been received, fully understood and successfully executed.
Specific positive response
In some cases, tpd concludes a successfully execution with a message of the type: +OK <more_info> where the more_info parameter gives some more information on the job just performed.
Specific negative response
A negative response in the form: -ERR <error_message> is supplied when a problem is encountered in the command receive/ recognize/execute process; the error_message parametes gives information on the occurred error.
Data prologue
In order to prepare the transmission of multiple data lines, the server issues a ready command of the form: +RDY <number_of_data_lines> [more_info] where the number_of_data_lines parameter indicates the number of data lines that will follow, while the more_info parameter gives more information, when necessary.
Data lines
Data lines are text lines through which the server sends the requested data to the client. There are several types of data lines, depending on the command issued by the client; for instance, a standard data line is sent to the client specifying the dielectric properties as requested, according to the current output format (see the Output formats section for a description of standard data lines).

Command reference

Currently, tpd acknowledges the commands listed below. In the command syntax, square brackets identify optional parameters, while angular brackets identify mandatory parameters.

FORM

USAGE
FORM [format_index]
PURPOSE
Sets or displays the output format index
PARAMETER(S)
format_index (integer); the index of the output format to be set; see the Output formats section for details; if the the parameter format_index is not supplied, the command simply displays the current output format index; format_index should be 0,1,2 or 3, otherwise the output format will remain unchanged.
RESPONSE
The only possible server response is a slightly modified positive response:
+OK format_index Tissue Dielectric Properties Server where format_index is the current output format index.

GETA

USAGE
GETA <frequency>
PURPOSE
Prints the properties of all tissues at the specified frequency value
PARAMETER(S)
frequency (real); the specified frequency in hertz; must be a real number in the 101 to 1011 Hz range.
RESPONSE
If the specified frequency is not valid, a specialized error message is produced, in the form: -ERR Bad frequency: ### Hz where ### represents the value of the frequency as understood by the server.
If the frequency is valid, a READY message is produced in the form: +RDY n where n represents the number of tissues managed by the server.

GETS

USAGE
GETS <tissue name> <frequency>
PURPOSE
Prints the properties of the specified tissue at the specified frequency value
PARAMETER(S)
tissue name (string); the name one of the specified tissue; must be one of the recognized tissues;
frequency (real); the specified frequency in hertz; must be a real number in the 10 Hz to 100 GHz range.
RESPONSE

GLIN

USAGE
GLIN <tissue name> <start frequency> <stop frequency> <number of intervals>
PURPOSE
Prints the properties of the specified tissue for multiple, linearly spaced, frequency values
PARAMETER(S)
tissue name (string); the name one of the specified tissue; must be one of the recognized tissues;
start frequency
stop frequency
number of intervals
RESPONSE

GLOG

USAGE
GLOG <tissue name> <start frequency> <stop frequency> <number of values per decade>
PURPOSE
Prints the properties of the specified tissue for multiple, logarithmically spaced, frequency values
PARAMETER(S)
tissue name (string); the name one of the specified tissue; must be one of the recognized tissues;
start frequency
stop frequency
number of values per decade
RESPONSE

HELP

USAGE
HELP
PURPOSE
Prints a summarized help page
PARAMETER(S)
None
RESPONSE

LIST

USAGE
LIST
PURPOSE
Prints a list of defined tissues
PARAMETER(S)
None
RESPONSE

PARM

USAGE
PARM <tissue name>
PURPOSE
Prints the parameters of the specified tissue
PARAMETER(S)
tissue name (string); the name one of the specified tissue; must be one of the recognized tissues;
RESPONSE

PRMA

USAGE
PRMA
PURPOSE
Prints the parameters of all tissues
PARAMETER(S)
None
RESPONSE

QUIT

USAGE
QUIT
PURPOSE
Close the connection
PARAMETER(S)
None
RESPONSE

Output formats

There are four output formats available, numbered 0 to 3. They are listed below, expressed in the C-language printf function format string style; for each format, an example is also provided. The parameters to pass to the format string are, in order, as follow (the expected unit of measurement in brackets).

  1. %-*s f= %12.4le Hz sig= %12.4le S/m eps= %12.4le tgl= %12.4le wav= %12.4le m dep= %12.4le m\r\n
    Example:
     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
  2. %-*s %12.4le %12.4le %12.4le %12.4le %12.4le %12.4le\r\n
    Example:
     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

  3. %-*s f= %12.4le Hz sig= %12.4le S/m eps= %12.4le\r\n
    Example:
     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

  4. %-*s %12.4le %12.4le %12.4le\r\n
    Example:
     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
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For any communication please contact Daniele Andreuccetti.