Julian's Home Page
Thanks for visiting my homepage, even if you arrived here by accident!
I make no apology for the bizarre ordering on this page, which I use mainly as an aide-memoire
You are looking at my home page. The main page for my Web
server is here. My blog is
I am a Member of the Professional Staff and Principal
Computational Scientist at Caltech's Center for
Advanced Computing Research, and a Fellow of the Institute of Physics. Prior to joining
Caltech, I held a staff position as a physicist at
CERN in Geneva, Switzerland, where I worked on the CMS
and Aleph experiments. Prior to that I was at the
Max Planck Institute
in Munich, working on the NA24 experiment, followed by a spell
working on the UA1 experiment for the Rutherford
Appleton Laboratory in Oxford. I have a Ph.D. in Particle Physics from the
University of Sheffield, and a B.Sc. in
Physics from the University of Manchester.
I was recently (2023)
interviewed by Matevz Leskovsek of
Animation of the
growth of Botnet traffic on a LAN.
Announcement of opportunity to work on Botnet Detection.
Caltech Coursera web page.
This is my short introduction to
Genetic Algorithms, part of the
School on Big Data Analytics. (Both links currently down while Caltech
migrates its content to the new Coursera system.)
A proposal from 2009 that incorporates sonification of
scientific data, entitled
cueing of significant events in large multivariate science and security
Pervasive Computing for Disaster Response
This was an NSF-funded project, in collaboration with UC
Irvine and IIT Gandhinagar, India. See the projec t website
The objective of this project is to develop key components of community-based
pervasive systems which will allow citizens to respond to disasters.
The Community Seismic
Network is a related project.
Sandra Fang, a Caltech SURF student in 2012, built a "Home
Hazard Weather Station" - check out her blog
here. This is a photo of
the completed prototype, which contains sensors for dangerous gasses such as CO
and LPG, acceleration, barometric pressure, humidity, sound, light, and
radiation (using a Geiger counter).
Judy Mou, a Caltech CS student, is now building a
situation awareness Android app for a tablet and/or Google TV, that takes the
sensor data from the Hazard Weather Station and combines it with a dynamically
updated collection of regional environmental, hazard and news information.
There is a
SURF Announcement of Opportunity to work on this project in 2013.
My guide to the
Voynich Manuscript is now
available on Amazon.
A report from Theresa Juaraz describing her SURF work on
Rugged encapsulation structures and acoustic instrument development for
inexpensive medical sensors
Develop Cell-Phone Medical Devices
I'm working with Prof. K. Mani Chandy on various aspects
of using cellphones as sensing devices, and in particular as first response
medical tools. Here's a
submitted to the
This is our idea for a
10c Medical Checkup.
Here is a
presentation by Victor Chu and Aleksander Palatnik, two SURF students who
worked with us on this project over the Summer 2009.
Old MWPC Data from Georges Charpak
In the late 80s, when I was a junior member of staff at
CERN in the computing division, I worked briefly on some multiwire proportional
chamber (MWPC) data that Georges Charpak needed to have rendered as graphics. I
used an Apollo workstation (See
http://en.wikipedia.org/wiki/Apollo_Computer) running in "borrowed mode"
(whereby the application had access to the whole screen of the device).
Charpak's data was of the head, chest and pelvis of one (or more?) patients, and
came in three files: heglo1, kulin1, and tihon2. I do not recall what these
names signified. I can remember Charpak getting quite excited when he saw the
images! These data may possibly have some historical significance (I have been
unable to find an email address for Charpak to ask him), so I have zipped them
up, together with example Fortran code I wrote for decoding them, in the
archive here for posterity.
AIRR, WinAIRR, Synthesizers,
Minisonic, Electronics, Sound, Video
Sony CDP-X555ES High End CD Player (1991)
Nakamichi RX-505 and RX-202 Cassette
Marantz SR 2000 Stereo Receiver
JVC Reverberation Amplifier ECA-102
Realistic 2-A Electrostatic
Software for handheld
devices and mobile phones.
A Modular Analogue Sound
This is a new project, started
in October 2009
Minisonic2 Sound Synthesizer project.
below shows my completed Minisonic2 sound synthesizer, which follows Doug
Shaw's original design published in Practical Electronics in the early 70s.
selection of Analogue Sound
My Nixie tube clock.
I found a nice little box to put it in in a shop in France.
The biggest challenge was drilling the required 1" diameter holes (I ended up using a Forstner bit).
Here are the guts:
At the top left hand corner
is the power supply, which produces 250V DC regulated no load. Underneath is the clock board, which uses
a programmed PIC to generate the required signals for the tubes. Then you see the four tubes at the bottom,
with the cathode wires and multiplex anode feed wires attaching them to the clock board. There are also two LEDs,
in the centre of the tubes, one of which flashes seconds, the other flashes half seconds. The two switches in the
top right hand corner are used to set the time and control the brightness of the tubes.
Here is the completed clock as installed in the sitting room, next to an
old writing cabinet.
I can't tell you how much fun making this clock was, and what a pleasure it
is to see the warm glow of the Nixies telling the correct time :-)
|I think I inherited my interest in
electronics, radios, scopes etc. from my Dad, who is also
a physicist. |
My Dad and I went to buy my first scope from a surplus shop in South London
... when we got there, they had about a dozen ex-Navy Solartron scopes for
sale. Of course, we only wanted one, and my Dad started going through each
of them testing all the functions. By the time he got to the last one, we
realised that not one of them was in perfect working condition: each had
something that didn't work.
However, the guy who owned the shop had one on his bench, the one he was
using. My Dad said "Well, what about *that* one?!". Of course it worked
perfectly, and that was the one I ended up with.
But the real event that started my electronics interest off was buying an
ex-GPO amplifier box from a surplus stall on St.Albans market. I have no
idea why I bought it, or how little I paid, but when I got it home and
opened it up, I was fascinated by all the little components, transistors,
resistors, capacitors. It also had lots of knobs on it ... and I think this
is a key attraction ... anything with a lot of knobs is by inherently very
interesting. Because I wanted to know how the amplifier worked, I wrote a
letter (I suppose I was about 12 years old) to the GPO. I told them the
number on the box, said I wanted some details, and waited for a reply.
A week or so later, a GPO post office van pulled up outside our house, and a
postman came down the drive carrying an envelope. Inside was a letter from a
Mr. Betton, and attached to the letter was the circuit diagram for the
amplifier. I still have it. Even more wonderful: the postman returned to the
van, opened up the back door, and fetched out a pile of Practical Wireless
and Practical Electronics magazines, tied up in string, which he then gave
to me. I still have all those magazines, dating from the early 60s through
to the early 70s. A gift from Mr. Betton, who said he had no further use for
them, and thought I might like them. That sort of helpful benevolence is a
My Single Ended
Stereo Tube Amplifier.
Uses a 6SN7GT as a pre-amp, and doubled-up 6GF7A
triodes as the power stage.
More details, including schematic,
spectrum analyzer I made in about 1990.
built for 220 Volts mains, and included a 9V rectifier.
The wiring is what I would call "Boutique", as you can see from this photo:
The audio input is fanned out into five separate bandpass filters of my
own design. Each filter is based around a 741 opamp, and tuned to a
different frequency from the rest. The output from each filter is fed to a
set of five LM341 LED driver ICs which each turn a bank of 10 LEDs on
depending on the output level. The 341 can run in two modes: the first mode
lights just the LED corresponding to the output voltage, the second lights
that LED and all below it. I had a switch to select between the two.
In this image the LEDs are in the second mode, and the Analyzer is
responding to a 5kHz sine wave input.
My design had several flaws, most serious was that there was interference
between the lowest two banks of LEDs. I think the filters are very wide, and
I was too ambitious in tuning their centre frequencies. The result is that,
for low frequency inputs, the lowest LED banks oscillate in brightness.
Vacuum Tubes / Valves
of the my vacuum tubes (or valves). Here is the
of my transistors. Here is the
Precision Tube Testers
A web page devoted to the various
models of Tube Testers made by the
Precision Apparatus Corporation, who were eventually bought up by B&K
Here's a picture of my Precision 660 ... this is
different from all other 660s I've seen in that it has more transistor and
tube sockets. I refurbished the case, since the original cloth-like covering
was very tatty. To do this I removed all the material, sanded down the
surfaces, and applied three coats of Danish Oil.
More pictures here, including showing the instrument
testing a 6SN7GT dual triode: (click on thumbnails for larger versions)
Lloyd's Solid State 5 Band Receiver
9H34W-34A five band receiver. The five bands are:
- AM Broadcast
- FM Broadcast
- Citizenís Band
- Aircraft 108 to 135 MHz
- Public Safety 149 to 173 MHz
Take a look at my
collection of Tektronix oscilloscopes and Plug Ins.
Look at the knob count on this
baby - my Tektronix 556 Dual Beam 'scope.
Here's an image of the 556 in use, testing the Minisonic2
My 214 mini storage 'scope
Here's my 310A, 516, 5441, 561A, 321A, 310 and 575 curve
The 7D20 plugged in to my 7904 mainframe:
Full details on all these Tektronix scopes is
Here's a TS-34A military 'scope dating from 1953, in
working condition. I have the original manual for this 'scope: the scan is
Here's my Telequipment S-43. There are two other plugins
for this 'scope in my collection.
This is a pic of a Solartron 'scope
identical to one I had as a boy. I believe these were used by the
British Navy. I cannot recall the model number, but it was perhaps an OS-20?
My dad and I drove down to Dartford (South London) to buy
it. When we arrived, the guy had around six
for sale, and another he was using on
his workbench for himself. My dad and I checked
each of the
others, and none of them worked properly, so we
ended up with the one the guy was using (we'd come a long way, and I think
he was a bit sheepish about how the rest didn't work)!
MJS Sweep Marker Generator
Hewlett Packard 608C VHF Signal Generator
Above picture shows the generator as received. Below
shows the generator after repainting, face cleaning etc.
Look at the engineering inside (there are several belts
I checked the performance using my Leader digital
frequency meter: the 608C produces beautiful sine waves and is accurate up
to at least 90Mhz (the limit of the Leader). The front panel meters
correctly show the modulation and output signal levels. Somebody said that
by using the analogue modulation input on the 608C it would be possible to
broadcast video to a nearby TV!
The manual for
the 608D (very similar to the 608C, but features a crystal marker) is
|A Non Linear Systems
Miniscope, model MS-15. Ebay: $18|
The manual for the similar MS-230 is
here (it is also on BAMA). Thanks to Marvin Moss.
Here is the
schematic for the MS-15.
And another version.
|Here's a UEI Oscilloscope,
model 301. It has sweep ranges of 30-500Hz, 500-5kHz, 5khz to 100kHz. This
cost me $1.00 on Ebay :-)|
TC-399 Reel to Reel tape deck
Information on the TC-399 can be found
My SECO Transistor and
Tunnel Diode tester, Model 250.
My Knight R/C
checker came with a 6E5 Magic Eye tube. Here's an animated GIF of the tube
as the checker moves through the correct measured resistance value:
Allied Knight R100 Communications Receiver
This communications receiver, dating from about 1957,
includes an S-meter and crystal calibrator.
More details here.
Communications Receivers (an SX-110, SX-71, S-107, S40A, WR600, SX-130,
SX-62, 5R10A, 5R100A, SP-44, SX-62)|
here for more details.
Aligning the HQ-110C with sweeps.
WinAIRR and AIRR (Anechoic and In-Room Response)
An article published in Speaker Builder Magazine describing AIRR,
software for measuring loudspeaker response using a SoundBlaster card. The more recent
version for Windows: WinAIRR.
|An article published in Speaker Builder Magazine on the subject of PC-based sound.
|An advert from
Practical Wireless, early 60s, showing the
Wharfedale Column Speaker,
constructed from a concrete pipe. My father made two of these and they
sounded very good!
|A program that generates Maximum Length Sequences, and
for each MLS cyclically autocorrelates it to demonstrate its special property. MLS is used
in acoustic measurement. It has a number of advantages over pulse-based measurements. Here
is some pseudo-code that implements MLS and the Fast
Hadamard Transform (FHT) to make the calculation much faster .... Contact me if you have questions ...
|A tool for plotting the frequency decomposition of the
sounds in a Windows WAV file.|
|Some code for manipulating the Windows Mixer.|
|Simulated sound of an instrument that monitors the collapse
of binary stars into one another (it's big).|
|A presentation made to the CMS Software and Computing Board in November 1996, showing a selection of audio/video
conferencing tools for Windows'95.|
|Some stuff on MBONE unicast routing proposed in 1994, but
|The Windows port of vic, one
of the LBL videoconferencing tool suite.|
|JJB is a member of the Audio
Engineering Society |
|Some code ( captjb.asm (Assembler) pmsj.c (C) getbuff.for
(Fortran) ) for decrypting Videocrypt by rotating and matching scanlines. This was
developed in 1994 for use with a Media Vision Pro Movie Spectrum video grabber card.|
A Selection of Research
Cars Owned and Sold
Currently enjoying a Mercedes Benz SLK320 from 2002. This
sports a 6 cylinder engine making 220 bhp. You can see the other cars I
considered before deciding on the SLK by visiting my
Previously: Jaguar E-Type, Porsche 911, Porsche 914, Triumph TR6, MGB GT
Here is where we like to go on holiday
apparatus for dynamically directing an application to a pre-defined multimedia
resource" - US Patent # 20020156870, issued 10/24/2002
thesis (1983) roughly converted from Waterloo
Script to HTML
Analysis and Visualisation (old)
workshop on HEP data visualisation and analysis.|
|The PAW(Physics Analysis
Workstation) is a software system used in the High Energy Phyics community for visualising
and processing large quantities of experimental data.|
|A presentation of PIAF, the parallel version of PAW,
describing the hardware and software configuration used for this multi-GByte capable
|A presentation of possible PIAF futures, as seen in 1995.|
|The programme of work of the Data Analysis
Techniques section in CN Division, for 1996. Presented at the CN POW Meeting in Yverdon.|
|An Evaluation of PAW,
presented at the HEPVIS'96 workshop (see above).|
|A description of the KUIP2TCL package, intended to
assist porting of KUIP-based GUIs to Tk/Tcl. This was originally scheduled for inclusion
in CERNLIB, but priorities changed ...|
Multimedia Archives of JJB
A selection of photographs.
Video of a talk I gave at the JHU eScience workshop:
Pages with Quotes
Nature, "Briefing" 1999: "It's sink or swim as a tidal
wave of data approaches"
AAAS Science Magazine, 1999: "Physicists and Astronomers
Prepare for a Data Flood"
NCSA Access Magazine: "Fascinating Magic",
|The Roswell Alien(1), and a different view. |
|A Dictionary of Cockney Rhyming slang.|
|This photo from the early
1980s is not of me, but of an unknown person who looked exactly like me at
that time. I believe it was from a newspaper article about dropping Radio 4
broadcasts on Long Wave. It was sent to me by my friend Steve Hancock of
CERN, who captioned it amusingly. The odd thing is that I had an identical
model Grundig radio at the time. Very weird.|
|An article in Sunset
house in Pasadena|
Java Bits and Pieces
|A simple Java Mathematical
expression evaluator. Source code is HERE.
*,-,/,+.sin,cos,tan,asin,acos,atan,min,max,atan2,exp,sqrt. E.g. it will
evaluate expressions like this, in double precision:|
java Evaluator "1+-min(-33,+4)*sin(0.5-0.1e-7) -atan2(3,4) +1/(0.051e-5)"
1+-min(-33,+4)*sin(0.5-0.1e-7)-atan2(3,4)+1/(0.051e-5) = 1960801.7782690835
|Code for a Kalman Filter Track Fitter,
developed by JJB and Rick Wilkinson in the GIOD Project (functional but
incomplete, put here because several people have asked me for it!)|
|Solving the Travelling Salesman problem, using a Genetic
|Track finding in a particle physics detector,
using a Genetic Algorithm|
|Arild Berg sent me a link
to his superb Maze
Solver, that uses a Genetic Algorithm|
|A simulation of life |
|A gravitational simulation of a set of masses rotating about
a fixed point |
|A simplistic Chess applet |
Of Historical Interest
|Here is a
programme of work document for
CERN's ECP/PT Group, dated August 1990, drafted by Paolo Palazzi, and containing
a contribution from (amongst others) R. Cailliau proposing a new project on
"HYPERTEXT / HYPERMEDIA". This was to later turn into the World Wide Web. Of
note is that this document pre-dates the official birth date of the world wide
web, which seems to be pinned at November 1990 ...
The PT group never really got off the ground, although I do remember a very
convivial set of meetings that took place in a good Auberge in the Jura. The
relevant section follows:
C: HYPERTEXT / HYPERMEDIA R. Cailliau
A PROPOSAL FOR A NEW PROJECT
Hypertext is a form of information storage that is a web of interconnected
nodes. The nodes contain information of some kind (document, program, picture,
sound, ...), the web lines are ways of getting from one node to another.
Searching in hypertext is aided by various mechanisms, each of different speed
and efficiency (there can be indexes and keyword lists). However, the user can
also navigate by following paths or just hopping along existing links in a
random manner. Thus there are no restrictions on how a node of information is
reached (in more classical systems one usually has to know part of the location
of the information). In addition, users can construct their own additions to the
set of links. The information nodes reside on different machines, the links
across machines are handled by hypertext servers resident in the machines.
In the context of LHC practically all information will have been generated by
machine. However, there is no unified way of accessing this information by
machione: different platforms are used and different formats have been used to
create the documents. Hypertext seems at the right stage of maturity to
introduce it as the unification of these otherwise incompatible sources of data.
The pilot project would aim at giving a minimum level of access to LHC related
information from any workstation. No attempt would be made to implement a large
range of features, thus one would not provide uniform access to bitmapped
pictures on all platforms, or to fully formatted text, since the formats for
pixels, character fonts etc. are too divergent on different systems. However,
one would attempt to provide
for a small number of the most popular formats, and just use plain alphanumeric
text in other cases. This is the only road to success.
- look at commercial products & get educated,
- select the level of services that can
reasonably be implemented and the platforms on which they would be provided,
- buy all components that can be bought,
Population should be done by incorporating existing documents only. The first
phase takes about 6 months.
The introduction of this technique cannot be done in isolation for one project:
it has to be done in conjunction with other services and groups such as CN, the
administration of CERN, and the accelerator divisions. Technical details of the
project are to be found in a proposal by T. Berners-Lee of CN, with whom I would
|1) The "SHIFT" proposal, CERN,
July 25, 1991 "Scalable
Heterogeneous Integrated Computing Facility Testbed". Design Study and
Implementation Proposal. (PDF)
The authors are: Jean-Philippe Baud, Julian Bunn, David Foster, Frederic Hemmer,
Erik Jagel, Joop Joosten, Olivier Martin, Les Robertson, Ben Segal and Rainer
2) Cost of intrusions/hackers on
CERN VAX Clusters, 1992
3) Report on trip to
DEC, 1992, information on Alpha chips, GIGASwitch, and other NDA
4) Trip report from 1996,
visit to MIT Media Lab, DEC sites, etc. other NDA
|CERN's first "Computer" ... the incredible Wim Klein. Here
is an extract (kindly provided from the CERN Archives by Miguel Marquina) from a
Klein in action, taken from his official retirement show at
CERN, December 10th. 1976. (There is some more
information about Wim Klein
This is an amusing story I was told about Klein. I have no
idea if it's true, or not.
An HP salesman came to CERN with one of HP's very first
digital calculators, which were exciting a lot of interest in the science
community at the time The DG himself arranged a demonstration, and invited
all the Directorate. The room was very crowded. The HP guy set up the machine,
and when he was ready, asked the audience for two many-digit numbers to multiply
together. Wim Klein had meanwhile come into the room unnoticed, wondering what
the crowd was looking at. Somebody suggested a couple of large numbers, and the
HP guy started to key them in to the calculator. And before he'd even finished
keying, Wim Klein shouted out the answer from the back of the room!
|The Floppy and
Flow User's Guide describes the use of this Fortran coding convention checker, tidier,
and Fortran to HTML converter, together with information on its companion program Flow,
used for making various analyses of Fortran code. You can download Floppy/Flow from Netlib.|
|An evaluation of LOGISCOPE. (old)|
|Using Logiscope to
analyse various CERN codes in
I was CTO in a company called Equate Systems, a small Los
Angeles based startup. We sold a software system I wrote called julianKeys. Most
notably this software was a featured download on Universal Music Group's Eminem
web page (Eminem Keys) at the time of release of "The EMINEM Show". You can
still download the Keys here, but they wont work fully as intended due to the
lack of server support...
http://www.eminem.com/eminemkeys/download/ . You can see an image of the
EMINEM Web Site as it appeared at that time, showing the
Eminem Keys download here. We also made
a version of JulianKeys for No Doubt.
Various random writings
|JJB's coin collection.|
|JJB's stamp collection.|
BUNN stuff (old)
Technology Tracking (old)
proposed WAN models for tackling the LHC computing problem.|
|An evaluation of the modelling tool NETWORK II.5.
|A proposal made in 1994
on how to provide massive numbers
of compute cycles for LHC simulation using PCs in the NICE
|A program I wrote for the Monty Hall problem
... extract from sci.math.num-analysis|
Reviews and Reports (old)
HTML Converters (old)
VMS stuff (old)
(The screen shows buttons for "Lose
Document", "Get Irritated", "Give Up", and "Click Away
Merrily for No Good Reason"!)
JJB discovers the picture grabbed with the Miro DC1 has an unhealthy blue tinge ...
(From "Whizz for Atomms" by Geoffrey Willans and Ronald Searle)