Some commercial devices that perfom the compression of data are found
to be available in the form of integrated circuits. The evaluation
softwares for those products have been used to see the possibility of
using such devices in our case.
ALDC
First, we considered the Adaptive
Lossless Data Compression(ALDC), which is running in an IBM product
ALDC1-40S-M[12]. We ran the ALDC software on the data files
generated with and without dynamic coding.
Table 1 shows the
compression factors.
In order to check that the ALDC algorithm is efficient when applied to
a single 3 by 3 tower array, we have generated a single electron with
different 
and in Pt values and passed them through the full detector
simulation. The original and the compressed data sizes are given in
Table 1. The compression factor remains to be more than 2 in almost
all cases. The variaion of the compression factor in and Pt
is consistent with our expectation taking into account the noise level
in barrel and in endcaps, and the size of the electromagnetic shower.
| SR type
|
event size
|
size with ALDC
|
compression factor
|
|
SR1(time+space)
|
41.2(21.0) kB
|
15.6(11.8) kB
|
2.6(1.7)
|
|
SR2-1(time, Et>2.5 GeV)
|
29.8(15.0) kB
|
11.7(8.5) kB
|
2.6(1.7)
|
|
SR2-2(time, Et>1.0 GeV)
|
138.9(69.8) kB |
53.1(40.4) kB
|
2.6(1.7)
|
|
SR2-3(time, Et>0.5 GeV)
| 381.4(191.7) kB |
139.4(109.5) kB
|
2.6(1.7)
|
|
SR2-4(time, Et>0.3 GeV)
| 662.8 (333.0)kB
|
245.1(189.9) kB
|
2.7(1.8)
|
Table 1: The data size before and after applying the ALDC algorithm and the
compression ratios with various Et thresholds.
The values in parentheses correspond to the dynamically coded data
Start
DCLZ
Another device that we found in the market is called
Data Compression Lempel Ziv(DCLZ)[13]. Similar
checks have been done with the software, and the results are given in
Table DCLZ.
| SR type
|
event size
|
size with DCLZ
|
compression factor
|
|
SR1(time+space)
|
41.2(21.0) kB
|
21.1(10.9) kB
|
3.3(1.9)
|
|
SR2-1(time, Et>2.5 GeV)
|
29.8 (15.0) kB
|
8.8(7.6) kB
|
3.4(2.0)
|
|
SR2-2(time, Et>1.0 GeV)
|
138.9(69.8) kB |
42.1(34.6) kB
|
3.3(2.0)
|
|
SR2-3(time, Et>0.5 GeV)
| 381.4(191.7) kB |
110.6(90.8) kB
|
3.4(2.1)
|
|
SR2-4(time, Et>0.3 GeV)
| 662.8 (333.0)kB
|
193.6(155.7) kB
|
3.4(2.1)
|
Table 2: The data size before and after applying the DCLZ algorithm and the
compression ratios with various Et thresholds.
The values in parentheses correspond to the dynamically coded data.
Start
DSP
we purchased the TMS320c50 DSP card produced by Texas
Instrumentto applicate
lossless data compression
algorithms in Hardwares. Its cycle time and Package type is 50/35 ns and 132 pin ceramic.
You can see our results of testing this DSP card applicating DPCM
coding and Residual Parametric coding here .
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