Data Mining in the SIMBAD database web log files
Wenger M., Oberto A.
Centre de Données astronomique de Strasbourg

Introduction

Session time

The SIMBAD web server produces a very large amount of information in its log file. The
available information consists of IP addresses, time of the query, query type and content, andinformation on the user's environment (hardware, operating system and browser).

At which time of the day is SIMBAD the most used, or the less used ? Can we find out whenusers work in different countries ? Here are some answers.

Users and countries
With the help of a geolocalisation database associating IP addresses with the corresponding
geographic location (country, city, coordinates, timezone) [ref 1], it is possible to associate
most of the IP addresses with a country.
With the approximation that one IP address correspond to one user, we can count the numberof different users in each country. Over two and a half years, this leads to the following map:

Activity %This presentation is based on the SIMBAD web server log files collected between January 2007
and June 2009. It shows some information rarely extracted from such logs.

Percentage of requests executed every hour
(CDS local time) on workdays. The minimum
is in the morning at 4-5 am. The maximum isat the begining of the afternoon, when also
the users of the american continent begin towork. The decrease during the evening isslow.

8765432
100 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Working day hour

The IP address allows us to infer the country of each access. Taking also in account the rules
defining for each country its Daylight Saving Time periods, we can analyze the working hours
in different countries.
France8Spain

8U.K.

8

8

7777666655554444333

322221

1

1000

100

612

18

23U.S.A.

8

766

554

4

3322

1

100

6

12

6

18

23

12

18

23

Japan

8

7000

61218

23

China

923

18

23

18

23

Chile

54

432

18

12

6

6
512

6

7

760

8

80

Russia

32

1

1000

61218

23

0

612Queries

223 countries, territories and islands have accessed SIMBAD in the last 30 months. Red andblue covered countries correspond probably to the most active countries in astronomy.
Surprisingly, there are very few countries remaining in white (no user at all) on this map.

Users working environment
What kind of hardware, operating system and browser are used by the SIMBAD users ? The
Apache log allows to answer these questions after having defined a few rules to infer
unspecified information (i.e. MacIntosh hardware can be deduced from MacOS operatingsystem). The figures are associated with unique IP addresses.
Hardware

WindowsMax OSLinux, *BSD
SolarisOS/2Unixes
CP/M
BeOS
VMS
AmigaOS
OS/400PC
MacIntosh
SunCellphones
PlayStations
Nintendo WiiIBM
SGI0Browsers

Operating system

10 20 30 40 50 60 70 80 90 100 %0IE
firefoxGoogleSky

80%

85%

90%

95%

Opera
Konqueror
Netscape
10 20 30 40 50 60

070 80 90 100 %5 10 15 20 25 30 35 40 45 %

75%

100%

% of Mac users

WindowsLinux

2 468 10 12 14 16 %The ten most popular names :NAME SMC
M 31
NAME SIRIUS
HD 8890 = POLARISM 33
NAME VEGA
M 101
HIP 32349 = SIRIUS
NAME LMC
NAME SGR DSPHMac OS80%85%90%

95%

100%

This correlation does not exist forLinux users...
% of Linux users

0QSO
TYC
RXGRB
GPM
CCDM
ClCD
3C
PSR
NLTT
ESO
IERS
GSN
LCRS
PN
MCG
[TP95]B3PG
NSV[BML2002]
WR[VV2003c]
LHS

00,1 0,2 0,3 0,4 0,5 %0 10 20 30 40 50 %In two and a half year, about 1,500,000 different identifiers were queried. The mostpopular names are listed below

java app.

There is a correlation between the GDP (GrossDomestic Product) per capita [ref 2] and thepercentage of Mac Os users in these countries
181614121086420Star
Galaxy
IR
V*X
Radio
*inCl
PM*
WD*
ClG
QSO
HII
**
gammaBurst
GinCl
Em*
PN
Cl*Pulsar
AGN
UV
SN
Blue
gamma
DkNeb
WR*
LensingEv
HH*inAssoc
QSO_Candidate

Safari

Australia
India
Korea Republic ofCzech Republic
Romania
Belgium
Switzerland
Chile
Austria
GreecePortugal
SwedenHungary
Colombia
TaiwanIsraelDenmark

75%

HD
MGC
NGC
NAME
HIP
V*
2MASS
1RXS
*M
2QZ
NGPFG
FIRST
IRAS
BD
GSC
SDSS
GJ
LEDA
HR
Cl*WD
ICSAO
UGC
ACO

0Mozilla

PCs and Windows are clearly dominant, but there are some clear differences among thecountries as it is shown below for the 34 countries having the most users :United States
Germany
FranceRussian FederationItaly
Spain
United KingdomBrazil
CanadaChina
PolandJapan
TurkeyUkraineMexicoNetherlands
Argentina

The Apache log contains also the query parameters from GET commands. Several information
can be extracted from them, namely the identifiers and catalogs used for identifier queries,
and the main object types associated with these catalogs.

10000 20000 30000 40000 50000

98765432100

10000 20000 30000 40000 50000

GDP per capita

Messier objects :M 1
M 45
M 3
M 51
M 13
M 57
M 15
M 67
M 16
M 80
M 17
M 81
M 31
M 82
M 32
M 83
M 33
M 87
M 42
M 101
M 44
M 104

Object names :LMC
SMC
ALCYONE
ALDEBARAN
ALGOL
ALTAIRANTARESARCTURUS
BETELGEUSECANOPUSCAPELLACENTAURUS A
CRAB NEBULADENEBEAGLE NEBULAFOMALHAUTHYADES
KOCHABMIRA
PEANUT NEBULAPLEIADES
POLARISPROCYONPROXIMA CENTAURIREGULUSRIGELSAGITTARIUS DWARF GALAXYSCULPTOR FILAMENT
SGR A
SIRIUSSPICA
VEGA

Various objects :NGC 253
NGC 1068
NGC 2362
ACO 1689 (galaxy cluster)NGC 2264
3C 273X Cyg X-1
SS 433
Granat 1915+105* alf Cen A* alf Cen B* eta Car* alf Ori
V* alf Lyr
V* TW Hya
GJ 581 (extrasolar planets)
GJ 436
GJ 876
HD 209458 (= V* V376 Peg)
HD 121409
HD 125019
HD 189733 (= V* V452 Vul)
HD 217107
HD 148478 (= V* alf Sco)

Queries by coordinates are defined by a center and a radius. These maps show the mostqueries areas in the sky :GDP per capita

Session duration

70EquatorialGalactical60coordinates

coordinates50403020References>= 240180­240120­18060­12030­60

10­305­104­53­42­301­210<1% of all sessions

Web accesses are stateless. Nevertheless, it is possible to infer some information concerning
the time a user is spending querying the database. This is done by checking all requests fromone IP address and considering that a session is ended if the time between two requests isover a given threshhold, which is here defined as 30 minutes.

min[ref 1] Geolocalisation database : http://ipinfodb.com[ref 2] Gross Domestic Product per capita database: http://www.indexmundi.com/