Table Of ContentEmergence, Complexity and Computation ECC
Andrew Adamatzky E ditor
Emergent
Computation
A Festschrift for Selim G. Akl
Emergence, Complexity and Computation
Volume 24
Series editors
Ivan Zelinka, Technical University of Ostrava, Ostrava, Czech Republic
e-mail: [email protected]
Andrew Adamatzky, University of the West of England, Bristol, UK
e-mail: [email protected]
Guanrong Chen, City University of Hong Kong, Hong Kong, China
e-mail: [email protected]
Editorial Board
Ajith Abraham, MirLabs, USA
Ana Lucia C. Bazzan, Universidade Federal do Rio Grande do Sul, Porto
Alegre, RS, Brazil
Juan C. Burguillo, University of Vigo, Spain
Sergej Čelikovský, Academy of Sciences of the Czech Republic, Czech Republic
Mohammed Chadli, University of Jules Verne, France
Emilio Corchado, University of Salamanca, Spain
Donald Davendra, Technical University of Ostrava, Czech Republic
Andrew Ilachinski, Center for Naval Analyses, USA
Jouni Lampinen, University of Vaasa, Finland
Martin Middendorf, University of Leipzig, Germany
Edward Ott, University of Maryland, USA
Linqiang Pan, Huazhong University of Science and Technology, Wuhan, China
Gheorghe Păun, Romanian Academy, Bucharest, Romania
Hendrik Richter, HTWK Leipzig University of Applied Sciences, Germany
Juan A. Rodriguez-Aguilar, IIIA-CSIC, Spain
Otto Rössler, Institute of Physical and Theoretical Chemistry, Tübingen, Germany
Vaclav Snasel, Technical University of Ostrava, Czech Republic
Ivo Vondrák, Technical University of Ostrava, Czech Republic
Hector Zenil, Karolinska Institute, Sweden
About this Series
The Emergence, Complexity and Computation (ECC) series publishes new
developments, advancements and selected topics in the fields of complexity,
computation and emergence. The series focuses on all aspects of reality-based
computation approaches from an interdisciplinary point of view especially from
applied sciences, biology, physics, or chemistry. It presents new ideas and inter-
disciplinary insight on the mutual intersection of subareas of computation, com-
plexity and emergence and its impact and limits to any computing based on
physical limits (thermodynamic and quantum limits, Bremermann’s limit, Seth
Lloyd limits…) as well as algorithmic limits (Gödel’s proof and its impact on
calculation,algorithmiccomplexity,theChaitin’sOmeganumberandKolmogorov
complexity, non-traditional calculations like Turing machine process and its con-
sequences,…) and limitations arising in artificial intelligence field. The topics are
(but not limited to) membrane computing, DNA computing, immune computing,
quantumcomputing,swarmcomputing,analogiccomputing,chaoscomputingand
computing on the edge of chaos, computational aspects of dynamics of complex
systems (systems with self-organization, multiagent systems, cellular automata,
artificiallife,…),emergenceofcomplexsystemsanditscomputationalaspects,and
agent based computation. The main aim of this series it to discuss the above
mentioned topics from an interdisciplinary point of view and present new ideas
coming from mutual intersection of classical as well as modern methods of com-
putation. Within the scope of the series are monographs, lecture notes, selected
contributions from specialized conferences and workshops, special contribution
from international experts.
More information about this series at http://www.springer.com/series/10624
Andrew Adamatzky
Editor
Emergent Computation
A Festschrift for Selim G. Akl
123
Editor
AndrewAdamatzky
Unconventional Computing Centre
University of the West of England
Bristol
UK
ISSN 2194-7287 ISSN 2194-7295 (electronic)
Emergence, Complexity andComputation
ISBN978-3-319-46375-9 ISBN978-3-319-46376-6 (eBook)
DOI 10.1007/978-3-319-46376-6
LibraryofCongressControlNumber:2016951682
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Foreword
ThisbookisdedicatedtoProf.SelimG.Akltohonor
his major research achievements in computer science
over four decades. In this way his colleagues, stu-
dents, and friends wish to express their gratitude to
this great scientist.
Dr. Akl completed his Ph.D. at McGill University
in1978.HehasbeenafacultymemberintheQueen’s
School of Computing (formerly Department of
Computing and Information Science) since 1978. Dr.
Akl serves as Director of the Queen’s School of
Computing since July 2007. He has held visiting
positions at the University of California Berkeley,
SelimG.Akl Simon Fraser University, the University of Puerto
Rico,ClarksonUniversity,andKentStateUniversity.
He was an SRI International Fellow at the Stanford Research Institute, in Menlo
Park, California, and an NSERC Senior Industrial Research Fellow at MacDonald
Dettwiler and Associates, in Richmond British Columbia. In 1990, he held the
Louis Néel Chair at the École Normale Supérieure de Lyon, France.
Throughout his career, Dr. Akl has made significant contributions in multiple
areas of computer science. He has published 170 journal articles and presented
180conferencepapers.Dr.Aklhaswrittenfourinfluentialmonographsonparallel
algorithms and parallel computation that are widely considered as landmarks
in parallel computation research and have been translated to many languages.
As will be discussed below, Dr. Akl’s research has made a strong impact on the
development of each area of computer science he has worked on. Dr. Akl has
collaboratedwithalargenumberofscientistsandhasmorethan100co-authorsin
publications in a wide range of areas.
Dr. Akl possesses the enviable skill of making complex ideas and visionary
concepts accessible and engaging, whether they appear in written form or in a
presentation. He is a brilliant scientific communicator. Dr. Akl has given plenary
v
vi Foreword
lectures at many international conferences and invited talks at universities world-
wide. He has supervised 24 Ph.D. theses and numerous M.Sc. theses. Dr. Akl has
always been very dedicated and supportive to his students and many of his former
students have leading positions in academia and industry.
Dr. Akl has made substantial contributions to the computer science community
throughhisselflessservice.HeistheEditorinChiefofParallelProcessingLetters
and has held editorial positions in 10 professional journals. He has served as a
program committee or organizing committee member of 70 computer science
conferences. In 2007, Dr. Akl served as General Chair of the Sixth International
ConferenceonUnconventionalComputationheldinKingston,Ontario.Dr.Aklhas
received a number of academic honors for research and teaching, including the
Queen's University Prize for Excellence in Research in 2008 and the Queen's
University Award for Excellence in Graduate Supervision in 2012.
Dr.Aklhasmadeimportantcontributionstomanyareasoftheoreticalcomputer
science. The following sections briefly summarize some of these achievements.
Parallel Computation and Parallel Algorithms
The goal of parallel computation is to reduce the time needed to solve a compu-
tational problem by using several processors that are working simultaneously.
Designing parallel algorithms, i.e., methods for solving problems efficiently on
parallel computers is a nontrivial task, requiring creativity and a way of thinking
completely different from the one used for sequential algorithms.
Dr. Akl was one of the pioneering researchers in this field and, since the early
1980s,hehascontributedmanyefficientparallelalgorithmstotheliterature.These
includealgorithmsforproblemssuchasselection,sorting,computingconvexhulls,
or enumerating combinatorial objects. The algorithms were designed to run on a
wide spectrum of computational models, such as shared memory machines, com-
binational circuits, and interconnection networks. Dr. Akl was among the first to
demonstratethelinksbetweenparallelcomputationandopticalcomputing,andthe
importance of parallel algorithms in real-time applications.
Inworkdealingwiththefoundationsofparallelcomputing,Dr.Aklwasthefirst
todemonstratesuperlinearspeedupinthenumberofprocessors,i.e.,heestablished
that there exist computational problems that can be solved with n processors more
thanntimesfasterthanonasequentialcomputer.Dr.Akluncoveredthreegeneral
computational paradigms within which parallel computation leads to a superlinear
improvement in performance. The results were groundbreaking and could be
viewed even as counter-intuitive.
In 2004, Dr. Akl demonstrated the existence of classes of inherently parallel
problems,thatis,classesofproblemsthatcanbesolvedonaparallelcomputerwith
an appropriate number of processors, but not on a sequential computer or even a
parallel computer with fewer processors. Furthermore, Dr. Akl has established the
impossibility of constructing a universal computer that could simulate any other
Foreword vii
computation. This is a significant foundational result with philosophical implica-
tions and, at least initially, it went against much of the commonly held beliefs in
computer science. By questioning common wisdom in parallel computation—
computations with uncertain time restrictions, computations under the influence
of the laws of nature, and computations subject to mathematical constraints—
Dr.Aklhasachievedsurprisingresults,withimplicationsthatcontinuetobetimely
and important.
Dr.Aklhaswrittenfourinfluentialmonographsthatareconsideredlandmarksof
parallel computation research, education, and practice. Each of these books was in
some sense a ‘first’. Before Parallel Sorting Algorithms (Academic Press, 1985)
thereexistednobookthatcoveredparallelalgorithmsexclusively.Thismonograph
becameamodelformanyotherbooksthatwerepublishedonparallelalgorithmsin
the years since. Dr. Akl’s second book The Design and Analysis of Parallel
Algorithms (Prentice Hall, 1989) was broader in scope and offered a unified and
rigoroustreatmentofthedifferenttechniquesfordesigningandanalyzingalgorithms
for parallel computers. The book is considered a classic and has been used exten-
sively worldwide. To this day, the only book offering an in-depth treatment of
parallel algorithms for computational geometry problems is Dr. Akl’s Parallel
Computational Geometry (Prentice Hall, 1993). Finally, Parallel Computation:
ModelsandMethods(PrenticeHall,1997)isanencyclopedicvolumethatpresents
themajorapproachestodesigningefficientparallelalgorithmsaswellasthedifferent
parallelcomputermodelsonwhichthealgorithmswouldbeexecuted.Thebookis
listed onAmazon among the 21best bookson algorithmics,not just parallel algo-
rithms. The creator of the list, Prof. Christoph Kögl from the University of
Kaiserslautern,describedthebookas“Possiblythebestbookonparallelalgorithms”.
Unconventional Computation and Natural Computation
Unconventional computation investigates the possibility of building computers
unlikeanythatarecurrentlyinuse.Themodelsinvestigatedincludebiomolecular,
chemical, optical and quantum computers, and analog neural networks or cellular
automata, among many others. Often parallelism captures the essence of uncon-
ventional computing and, consequently, Dr. Akl’s transition into unconventional
computation can be viewed as a logical continuation to his extensive work in
parallel computation.
Dr. Akl’s work in unconventional computation has various motivations and
goals. One goal is to understand the natural processes by modeling them as algo-
rithms,e.g.,plantrespirationasacellularautomatonalgorithmorphotosynthesisas
a quantum process. Dr. Akl used two-dimensional cellular automata to provide
efficientsolutionsforcomputationalproblemsinplantrespirationthathadremained
open for several years. Another goal is to seek inspiration from nature for com-
putational models such as genetic algorithms, neural networks, or swarm intelli-
gence.Afurthergoalistousenaturallawstoperformmoreefficientcomputations,
viii Foreword
for example, in biomolecular computing, chemical computing, or quantum com-
puting. Significantly Dr. Akl’s work has uncovered computational problems that
canbeperformedonaquantumcomputerbutnoteveninprincipleonanyclassical
computer. Furthermore, in considering physical systems as computational models
the work tackles philosophical questions about the definition of computation, that
is, what it means ‘to compute’.
Work in Other Research Areas
InadditiontotheareasofParallelComputationandUnconventional Computation,
Dr. Akl has made important contributions in at least four other areas which we
brieflymentionhere.SelimAklisapioneerinthefieldofComputationalGeometry
working in the nascent field while still a Ph.D. student at McGill. Dr. Akl
co-authored several seminal papers among them a very effective and often-cited
heuristic to compute the convex hull of a planar point set. Dr. Akl continued his
exploration of Computational Geometry and published several parallel algorithms
to solve geometric problems. In the area of Design and Analysis of Combinatorial
Algorithms he was the co-editor of the book Algorithms and Data Structures
(Springer 1995) and served on the Editorial Board of the journal Information
Processing Letters (North Holland). Dr. Akl was a pioneer of modern
Cryptography and Data Security, presenting a paper on digital signatures as early
as 1981. Dr. Akl’s elegant and ingenious solution to the problem of controlling
accesstoinformationinahierarchicalorganizationopenedupanentiresubfieldof
research. Over the years many researchers have attempted, without success, to
improve on his solution which remains the state of the art for access control in a
hierarchy.GeneralizationstothissolutionaredescribedinDr.Akl’sbookAdaptive
Cryptographic Access Control (Springer, 2010) and applied to a number of com-
puter security issues, most notably the protection of information in data
warehouses.
Since 2009, Dr. Akl has collaborated with a cardiologist in the area of
Biomedical Computing and Computer Assisted Medicine. The work uses uncon-
ventional algorithmic techniques to analyze electrocardiograms, towards a better
diagnosis and treatment of cardiac arrhythmias. While the clinical work is still in
early stages, the research has produced a substantial number of publications and
two completed Ph.D. degrees supervised by Dr. Akl.
Personal Recollections
The undersigned have had the good fortune to be Selim’s long time colleagues at
the Queen’s School of Computing and we conclude with a few more personal
remarks.
Foreword ix
Selim is truly a Renaissance man. Along with his eclectic research interests
Selim is also actively involved in the creative arts. He has a background in theater
and was a prominent fixture of the Kingston theater scene. Selim founded the
FrenchspeakingtheatercompanyLesTréteauxdeKingston,shortlyafterhearrived
to Kingston, and the company has been continuously active to this day. Currently
Selim’screativeoutletisphotography.Theexpertcareandattentiontodetailfound
in his research articles can be seen in his beautiful photographs. Since 2005 his
pictures grace the cover of the monthly magazine Vista.
As a colleague Selim has always been supportive and encouraging. His
unbounded energy and creativity is stimulating to colleagues and students alike.
Selim leads a weekly seminar group that has continued without interruption for
decades. The group includes professors, researchers, clinicians, and students, all
from diverse backgrounds that, in addition to computing, include biology, philos-
ophy, and surgery. It is Selim’s affable nature that is the force of attraction that
brings this diverse group of individuals together.
Selimhasnaturalleadershipqualitiesthatimpressivelyenhancehisproductivity.
Perhapshismostsignificanthumancharacteristicishisgenerosityandkindness.He
works tirelessly to assist his colleagues and students, always with encouragement,
and never with derision. There are many researchers today, those who were
supervised by Selim, orworked with him as colleagues,whosecareers aremarked
indelibly by his strong influence. We are all richer for knowing and working with
him.
We,togetherwithallcontributorsofthisvolume,wishSelimcontinuedsuccess
in the years to come.
Kingston, Canada David Rappaport
July 2016 Kai Salomaa
