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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)
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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.
- 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
IFAC-CNR, Florence (Italy), 1997-2021.
For any communication please contact
Daniele
Andreuccetti.
