We propose a simple and effective tool for the expression of tasks such as cross-layer optimization strategies
or sensors-related applications. The approach is based
on what we refer to as “reflective and refractive variables”. Both types of variables are associated with external entities, e.g. sensors or actuators. A reflective
variable is a volatile variable, that is, a variable that
might be concurrently modified by multiple threads. A
library of threads is made available, each of which interfaces a set of sensors and continuously update the value
of a corresponding set of sensors. One such thread is
“cpu”, which exports the current level of usage of the
local CPU as an integer between 0 and 100. This integer is reflected into the integer reflective variable cpu.
A refractive variable is a reflective variable that can be
modified. Each modification is caught and interpreted
as a request to change the value of an actuator. For
instance, setting variable “tcp sendrate” would request
a cross-layer adjustment to the thread interfacing the
local TCP layer entity. This allows express in an easy
way complex operations in the application layer of any
programming language, e.g. plain old C. We describe
our translator and the work we are carrying out within
PATS to build simple and powerful libraries of scripts
based on reflective and refractive variables, including
robotics applications and RFID tags processing.
Issues in Client-Server Communication
Addressing
Blocking versus non-blocking
Buffered versus unbuffered
Reliable versus unreliable
Server architecture: concurrent versus sequential
Scalability
Presentation on Static Network Architecture for multi-programming and multi-processing. Architecture, Ring Architecture, Ring Chordal Architecture, Barrel Shifter Architecture, Fully Connected Architecture.
Issues in Client-Server Communication
Addressing
Blocking versus non-blocking
Buffered versus unbuffered
Reliable versus unreliable
Server architecture: concurrent versus sequential
Scalability
Presentation on Static Network Architecture for multi-programming and multi-processing. Architecture, Ring Architecture, Ring Chordal Architecture, Barrel Shifter Architecture, Fully Connected Architecture.
In this paper, a review for consistency of data replication protocols has been investigated. A brief
deliberation about consistency models in data replication is shown. Also we debate on propagation
techniques such as eager and lazy propagation. Differences of replication protocols from consistency view
point are studied. Also the advantages and disadvantages of the replication protocols are shown. We
advent into essential technical details and positive comparisons, in order to determine their respective
contributions as well as restrictions are made. Finally, some literature research strategies in replication
and consistency techniques are reviewed.
A Metamodel and Graphical Syntax for NS-2 ProgramingEditor IJCATR
One of the most important issues, around the world, which manufacturers pay special attention to is to promote their
activities in order to be able to give high quality products or services. Perhaps the first advice to achieve this goal is simulation idea.
Therefore, simulation software packages with different properties have been made available. One of the most applicable simulators is
NS-2 which suffers from internal complexity. On the other hand, Domain Specific Modeling Languages can make an abstraction level
by which we can overcome the complexity of NS-2, increase the production speed, and promote efficiency. So, in this paper, we
introduce a Domain Specific Metamodel for NS-2.This new metamodel paves the ways for introducing abstract syntax and modeling
language syntax. In addition, created syntax in Domain Specific Modeling Language is supported by a graphical modeling tool.
Towards high performance computing(hpc) through parallel programming paradigm...ijpla
Nowadays, we are to find out solutions to huge computing problems very rapidly. It brings the idea of parallel computing in which several machines or processors work cooperatively for computational tasks. In the past decades, there are a lot of variations in perceiving the importance of parallelism in computing machines. And it is observed that the parallel computing is a superior solution to many of the computing limitations like speed and density; non-recurring and high cost; and power consumption and heat dissipation etc. The commercial multiprocessors have emerged with lower prices than the mainframe machines and supercomputers machines. In this article the high performance computing (HPC) through parallel programming paradigms (PPPs) are discussed with their constructs and design approaches.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
All new computers have multicore processors. To exploit this hardware parallelism for improved
perf
ormance, the predominant approach today is multithreading using shared variables and locks. This
approach has potential data races that can create a nondeterministic program. This paper presents a
promising new approach to parallel programming that is both
lock
-
free and deterministic. The standard
forall primitive for parallel execution of for
-
loop iterations is extended into a more highly structured
primitive called a Parallel Operation (POP). Each parallel process created by a POP may read shared
variable
s (or shared collections) freely. Shared collections modified by a POP must be selected from a
special set of predefined Parallel Access Collections (PAC). Each PAC has several Write Modes that
govern parallel updates in a deterministic way. This paper pre
sents an overview of a Prototype Library
that implements this POP
-
PAC approach for the C++ language, including performance results for two
benchmark parallel programs.
Enhancing AODV Routing Protocol to Eliminate Black Hole Attack in MANET.......................................1
Ei Ei Khin and Thandar Phyu
Adaptive Search Information Technology in the University Library ........................................................ 15
Andriy Andrukhiv and Dmytro Tarasov
Educational Data Mining: Performance Evaluation of Decision Tree and Clustering Techniques Using
WEKA Platform........................................................................................................................................... 26
Ritika Saxena
Hamiltonian cycle in graphs 흈4 ≥ ퟐn....................................................................................................... 38
Nguyen Huu Xuan Truong and Vu Dinh Hoa
Truly dependable software systems should be built with structuring techniques able to decompose the software complexity without
hiding important hypotheses and assumptions such as those regarding
their target execution environment and the expected fault- and system
models. A judicious assessment of what can be made transparent and
what should be translucent is necessary. This paper discusses a practical
example of a structuring technique built with these principles in mind:
Reflective and refractive variables. We show that our technique offers
an acceptable degree of separation of the design concerns, with limited
code intrusion; at the same time, by construction, it separates but does
not hide the complexity required for managing fault-tolerance. In particular, our technique offers access to collected system-wide information
and the knowledge extracted from that information. This can be used
to devise architectures that minimize the hazard of a mismatch between
dependable software and the target execution environments.
advanced computer architesture-conditions of parallelismPankaj Kumar Jain
This PPT contains Data and Resource Dependencies,Control Dependence,Resource Dependence,Bernstein’s Conditions ,Hardware And Software Parallelism,Types of Software Parallelism
HIGH-LEVEL LANGUAGE EXTENSIONS FOR FAST EXECUTION OF PIPELINE-PARALLELIZED CO...ijpla
The last few years have seen multicore architectures emerge as the defining technology shaping the future
of high-performance computing. Although multicore architectures present tremendous performance
potential, to realize the true potential of these systems, software needs to play a key role. In particular,
high-level language abstractions and the compiler and the operating system should be able to exploit the
on-chip parallelism and utilize underlying hardware resources on these emerging platforms. This paper
presents a set of high-level abstractions that allow the programmer to specify, at the source-code level, a
variety to of parameters related to parallelism and inter-thread data locality. These abstractions are
implemented as extensions to both C and Fortran. We present the syntax of these directives and also
discuss their implementation in the context of source-to-source transformation framework and autotuning
system. The abstractions are particularly applicable to pipeline parallelized code. We demonstrate the
effectiveness of these strategies of a set of pipeline parallel benchmarks on three different multicore
platforms.
In this paper, a review for consistency of data replication protocols has been investigated. A brief
deliberation about consistency models in data replication is shown. Also we debate on propagation
techniques such as eager and lazy propagation. Differences of replication protocols from consistency view
point are studied. Also the advantages and disadvantages of the replication protocols are shown. We
advent into essential technical details and positive comparisons, in order to determine their respective
contributions as well as restrictions are made. Finally, some literature research strategies in replication
and consistency techniques are reviewed.
A Metamodel and Graphical Syntax for NS-2 ProgramingEditor IJCATR
One of the most important issues, around the world, which manufacturers pay special attention to is to promote their
activities in order to be able to give high quality products or services. Perhaps the first advice to achieve this goal is simulation idea.
Therefore, simulation software packages with different properties have been made available. One of the most applicable simulators is
NS-2 which suffers from internal complexity. On the other hand, Domain Specific Modeling Languages can make an abstraction level
by which we can overcome the complexity of NS-2, increase the production speed, and promote efficiency. So, in this paper, we
introduce a Domain Specific Metamodel for NS-2.This new metamodel paves the ways for introducing abstract syntax and modeling
language syntax. In addition, created syntax in Domain Specific Modeling Language is supported by a graphical modeling tool.
Towards high performance computing(hpc) through parallel programming paradigm...ijpla
Nowadays, we are to find out solutions to huge computing problems very rapidly. It brings the idea of parallel computing in which several machines or processors work cooperatively for computational tasks. In the past decades, there are a lot of variations in perceiving the importance of parallelism in computing machines. And it is observed that the parallel computing is a superior solution to many of the computing limitations like speed and density; non-recurring and high cost; and power consumption and heat dissipation etc. The commercial multiprocessors have emerged with lower prices than the mainframe machines and supercomputers machines. In this article the high performance computing (HPC) through parallel programming paradigms (PPPs) are discussed with their constructs and design approaches.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
All new computers have multicore processors. To exploit this hardware parallelism for improved
perf
ormance, the predominant approach today is multithreading using shared variables and locks. This
approach has potential data races that can create a nondeterministic program. This paper presents a
promising new approach to parallel programming that is both
lock
-
free and deterministic. The standard
forall primitive for parallel execution of for
-
loop iterations is extended into a more highly structured
primitive called a Parallel Operation (POP). Each parallel process created by a POP may read shared
variable
s (or shared collections) freely. Shared collections modified by a POP must be selected from a
special set of predefined Parallel Access Collections (PAC). Each PAC has several Write Modes that
govern parallel updates in a deterministic way. This paper pre
sents an overview of a Prototype Library
that implements this POP
-
PAC approach for the C++ language, including performance results for two
benchmark parallel programs.
Enhancing AODV Routing Protocol to Eliminate Black Hole Attack in MANET.......................................1
Ei Ei Khin and Thandar Phyu
Adaptive Search Information Technology in the University Library ........................................................ 15
Andriy Andrukhiv and Dmytro Tarasov
Educational Data Mining: Performance Evaluation of Decision Tree and Clustering Techniques Using
WEKA Platform........................................................................................................................................... 26
Ritika Saxena
Hamiltonian cycle in graphs 흈4 ≥ ퟐn....................................................................................................... 38
Nguyen Huu Xuan Truong and Vu Dinh Hoa
Truly dependable software systems should be built with structuring techniques able to decompose the software complexity without
hiding important hypotheses and assumptions such as those regarding
their target execution environment and the expected fault- and system
models. A judicious assessment of what can be made transparent and
what should be translucent is necessary. This paper discusses a practical
example of a structuring technique built with these principles in mind:
Reflective and refractive variables. We show that our technique offers
an acceptable degree of separation of the design concerns, with limited
code intrusion; at the same time, by construction, it separates but does
not hide the complexity required for managing fault-tolerance. In particular, our technique offers access to collected system-wide information
and the knowledge extracted from that information. This can be used
to devise architectures that minimize the hazard of a mismatch between
dependable software and the target execution environments.
advanced computer architesture-conditions of parallelismPankaj Kumar Jain
This PPT contains Data and Resource Dependencies,Control Dependence,Resource Dependence,Bernstein’s Conditions ,Hardware And Software Parallelism,Types of Software Parallelism
HIGH-LEVEL LANGUAGE EXTENSIONS FOR FAST EXECUTION OF PIPELINE-PARALLELIZED CO...ijpla
The last few years have seen multicore architectures emerge as the defining technology shaping the future
of high-performance computing. Although multicore architectures present tremendous performance
potential, to realize the true potential of these systems, software needs to play a key role. In particular,
high-level language abstractions and the compiler and the operating system should be able to exploit the
on-chip parallelism and utilize underlying hardware resources on these emerging platforms. This paper
presents a set of high-level abstractions that allow the programmer to specify, at the source-code level, a
variety to of parameters related to parallelism and inter-thread data locality. These abstractions are
implemented as extensions to both C and Fortran. We present the syntax of these directives and also
discuss their implementation in the context of source-to-source transformation framework and autotuning
system. The abstractions are particularly applicable to pipeline parallelized code. We demonstrate the
effectiveness of these strategies of a set of pipeline parallel benchmarks on three different multicore
platforms.
SENSOR SIGNAL PROCESSING USING HIGH-LEVEL SYNTHESIS AND INTERNET OF THINGS WI...pijans
Sensor routers play a crucial role in the sector of Internet of Things applications, in which the capacity for transmission of the network signal is limited from cloud systems to sensors and its reversal process. It describes a robust recognized framework with various architected layers to process data at high level synthesis. It is designed to sense the nodes instinctually with the help of Internet of Things where the applications arise in cloud systems. In this paper embedded PEs with four layer new design framework architecture is proposed to sense the devises of IOT applications with the support of high-level synthesis DBMF (database management function) tool.
SENSOR SIGNAL PROCESSING USING HIGH-LEVEL SYNTHESIS AND INTERNET OF THINGS WI...pijans
Sensor routers play a crucial role in the sector of Internet of Things applications, in which the capacity for transmission of the network signal is limited from cloud systems to sensors and its reversal process. It describes a robust recognized framework with various architected layers to process data at high level synthesis. It is designed to sense the nodes instinctually with the help of Internet of Things where the applications arise in cloud systems. In this paper embedded PEs with four layer new design framework architecture is proposed to sense the devises of IOT applications with the support of high-level synthesis DBMF (database management function) tool.
In the Fifties, Arnold Schönberg introduced a model for music composition that he called "Grundgestalt", the basic shape. In this seminar I show how I interpreted this concept as a generative music model that translates the orbits of dynamic systems into musical components. I also describe a family of experiments that led me to the creation of simple and not-so-simple musical compositions, which I call "my little Grundgestalten”. Excerpts from a selection of those compositions will be presented.
Models and Concepts for Socio-technical Complex Systems: Towards Fractal Soci...Vincenzo De Florio
We introduce fractal social organizations—a novel class of socio-technical complex systems characterized
by a distributed, bio-inspired, hierarchical architecture. Based on a same building block that is recursively
applied at different layers, said systems provide a homogeneous way to model collective behaviors of
different complexity and scale. Key concepts and principles are enunciated by means of a case study and a
simple formalism. As preliminary evidence of the adequacy of the assumptions underlying our systems here
we define and study an algebraic model for a simple class of social organizations. We show how despite its
generic formulation, geometric representations of said model exhibit the spontaneous emergence of complex
hierarchical and modular patterns characterized by structured addition of complexity and fractal nature—
which closely correspond to the distinctive architectural traits of our fractal social organizations. Some
reflections on the significance of these results and a view to the next steps of our research conclude this
contribution.
On the Role of Perception and Apperception in Ubiquitous and Pervasive Enviro...Vincenzo De Florio
Building on top of classic work on the perception of natural systems this paper addresses the role played by such quality in
environments where change is the rule rather than the exception. As in natural systems, perception in software systems takes two major forms: sensory perception and awareness (also known as apperception). For each of these forms we introduce semi-formal models that allow us to discuss and characterize perception and apperception failures in software systems evolving in environments subjected to rapid and sudden changes—such as those typical of ubiquitous and pervasive computing. Our models also provide us with two partial orders to compare such software systems with one another as well as with reference environments. When those
environments evolve or change, or when the software themselves evolve after their environments, the above partial orders may be used to compute new environmental fits and different strategic fits and gain insight on the degree of resilience achieved through the current adaptation steps.
Service-oriented Communities: A Novel Organizational Architecture for Smarter...Vincenzo De Florio
The seminar I shall present at Masaryk University in Brno on May 19, 2016. A video of this presentation is available at https://www.youtube.com/edit?video_id=Fu5kv0sFWG4
On codes, machines, and environments: reflections and experiencesVincenzo De Florio
Code explicitly refers to a reference machine and, implicitly, to a set of conditions often called the system model and the fault model.
If one wants to guarantee an agreed-upon quality of service, one needs to either make assumptions about those conditions or adapt to them.
In this lecture I present this problem and a number of solutions, both practical and theoretical, that I have devised in the course of my career.
Although the main accent is on programming languages, here I provide links and references to other approaches that operate at algorithmic- and system-level.
Tapping Into the Wells of Social Energy: A Case Study Based on Falls Identifi...Vincenzo De Florio
Are purely technological solutions the best answer we can get to the shortcomings our organizations are often experiencing today? The results we gathered in this work lead us to giving a negative answer to such question. Science and technology are powerful boosters, though when they are applied to the “local, static organization of an obsolete yesterday” they fail to translate in the solutions we need to our problems. Our stance here is that those boosters should be applied to novel, distributed, and dynamic models able to allow us to escape from the local minima our societies are currently locked in. One such model is simulated in this paper to demonstrate how it may be possible to tap into the vast basins of social energy of our human societies to realize ubiquitous computing sociotechnical services for the identification and timely response to falls.
Accompanying paper available at https://arxiv.org/abs/1508.06655
How Resilient Are Our Societies?Analyses, Models, Preliminary ResultsVincenzo De Florio
Traditional social organizations such as those for the management of healthcare and civil defense are the result of designs and realizations that matched well with an operational
context considerably different from the one we are experiencing today: A simpler world, characterized by a greater amount of resources to match less users producing lower peaks of requests.
The new context reveals all the fragility of our societies: unmanageability is just around the corner unless we do not complement the “old recipes” with smarter forms of social organization.
Here we analyze this problem and propose a refinement to our fractal social organizations as a model for resilient cyber-physical societies. Evidence to our claims is provided by simulating our model in terms of multi-agent systems.
This course teaches engineering students how to program in C. I gave this course for several years in the framework of the "Advanced Technology Higher Education Network" / SOCRATES program.
A framework for trustworthiness assessment based on fidelity in cyber and phy...Vincenzo De Florio
We introduce a method for the assessment of trust for n-open systems based on a measurement of fidelity and present a prototypic implementation of a complaint architecture. We construct a MAPE loop which monitors the compliance between corresponding figures of interest in cyber- and physical domains; derive measures of the system’s trustworthiness; and use them to plan and execute actions aiming at guaranteeing system safety and resilience. We conclude with a view on our future work.
Presented at ANTIFRAGILE'15
Companion paper available at http://www.sciencedirect.com/science/article/pii/S1877050915008923
A behavioural model for the discussion of resilience, elasticity, and antifra...Vincenzo De Florio
Resilience is one of those "general systems attributes" that appear to play a central role in several disciplines - including ecology, business, psychology, industrial safety, microeconomics, computer networks, security, management science, cybernetics, control theory, crisis and disaster management. Resilience thus seems to be "needed" everywhere; and yet, even in the framework of a same discipline, it is not easy to define it precisely and consensually. To add to the confusion, other terms such as elasticity, change tolerance, and antifragility, although clearly related to resilience, cannot be easily differentiated.
In this talk I tackle this problem by introducing a behavioural model of resilience. I interpret resilience as the property emerging from the interaction of the behaviours produced by two "players": a system and a hosting environment. The outcome of said interaction depends on both intrinsic and extrinsic factors, including the systemic "traits" of the system but also how the system's endowment matches the requirements expressed by the behaviours of the environment. I show how the behavioural approach provides a unifying framework within which it is possible to express coherent definitions for elasticity, change tolerance, and antifragility.
A Behavioral Interpretation of Resilience and AntifragilityVincenzo De Florio
In this presentation I discuss resilience and antifragility as behaviors resulting from the coupling of a system and its environment(s). Depending on the interactions between these two "ends" and on the quality of the individual behaviors that they may exercise, different strategies may be chosen: elasticity (change masking); entelechism (change tolerance); and antifragility (adapting to & learning from change). When the environment is very simple and only capable of so-called "random behavior", often the only effective strategy towards resilience is off-line dimensioning of redundancy as a result of a worst-case assessment of disturbances and/or threats. Much more complex and variegated is the case when both systems and environments are "intelligent" -- or at least able to exercise complex teleological and extrapolatory behaviors. In this case both system and ambient may choose among a variety of strategies in what could be regarded as a complex evolutionary game theory setting.
Community Resilience: Challenges, Requirements, and Organizational ModelsVincenzo De Florio
An important challenge for human societies is that of mastering the complexity of Community Resilience, namely “the sustained ability of a community to utilize available resources to respond to, withstand, and recover from adverse situations”. The above concise definition puts the accent on an important requirement: a community’s ability to
make use in an intelligent way of the available resources, both institutional and spontaneous, in order to match the complex evolution of the “significant multi-hazard threats characterizing a crisis”. Failing to address such requirement exposes a community to extensive failures that are known to exacerbate the consequences of natural and human-induced crises. As a consequence, we experience today an urgent need to respond to the challenges of community resilience engineering. This problem, some reflections, and preliminary prototypical contributions constitute
the topics of this presentation.
A companion article is available at https://dl.dropboxusercontent.com/u/67040428/Articles/serene14.pdf
On the Behavioral Interpretation of System-Environment Fit and Auto-ResilienceVincenzo De Florio
Already 71 years ago Rosenblueth, Wiener, and Bigelow introduced the concept of the “behavioristic study of natural events” and proposed a classification of systems according to the quality of the behaviors they are able to exercise. In this presentation we consider the problem of the resilience of a system when deployed in a changing environment, which we tackle by considering the behaviors both the system organs and the environment mutually exercise. We then introduce a partial order and a metric space for those behaviors, and we use them to define a behavioral interpretation of the concept of system-environment fit. Moreover we suggest that behaviors based on the extrapolation of future environmental requirements would allow systems to proactively improve their own system-environment fit and optimally evolve their resilience. Finally we describe how we plan to express a complex optimization strategy in terms of the concepts introduced in this presentation.
The paper accompanying this presentation is available at https://dl.dropboxusercontent.com/u/67040428/Articles/DF14b_Wiener21stA.pdf
Antifragility = Elasticity + Resilience + Machine Learning. Models and Algori...Vincenzo De Florio
Presentation for the ANTIFRAGILE 2014 workshop, https://sites.google.com/site/resilience2antifragile/
Abstract: We introduce a model of the fidelity of open systems—fidelity being interpreted here as the compliance between corresponding
figures of interest in two separate but communicating domains. A special case of fidelity is given by real-timeliness and synchrony,
in which the figure of interest is the physical and the system’s notion of time. Our model covers two orthogonal aspects of fidelity,
the first one focusing on a system’s steady state and the second one capturing that system’s dynamic and behavioral characteristics.
We discuss how the two aspects correspond respectively to elasticity and resilience and we highlight each aspect’s qualities and
limitations. Finally we sketch the elements of a new model coupling both of the first model’s aspects and complementing them
with machine learning. Finally, a conjecture is put forward that the new model may represent a first step towards compositional
criteria for antifragile systems.
Service-oriented Communities and Fractal Social Organizations - Models and co...Vincenzo De Florio
Presentation given by Vincenzo De Florio at the Ceremony for the handing of the 2013 Faculty Awards.
Keywords: Fractal social organizations; service oriented communities; mutual assistance communities
Seminarie Computernetwerken 2012-2013: Lecture I, 26-02-2013Vincenzo De Florio
Seminarie Computernetwerken is a course given at Universiteit Antwerpen, Belgium
A series of seminars focusing on various themes changing from year to year.
This year's themes are: resilience, behaviour, evolvability; in systems, networks, and organizations
In what follows we describe:
themes of the course
view to the seminars
rules of the game
TOWARDS PARSIMONIOUS RESOURCE ALLOCATION IN CONTEXT-AWARE N-VERSION PROGRAMMINGVincenzo De Florio
Adopting classic redundancy-based fault-tolerant schemes in
highly dynamic distributed computing systems does not
necessarily result in the anticipated improvement in
dependability. This primarily stems from statically predefined
redundancy configurations employed within many classic
dependability strategies, which as well known may negatively
impact the schemes' overall effectiveness. In this paper, a
novel dependability strategy is introduced encompassing
advanced redundancy management, aiming to autonomously
tune its internal configuration in function of disturbances
observed. Policies for parsimonious resource allocation are
presented thereafter, intent upon increasing the scheme's cost
effectiveness without breaching its availability objective. Our
experimentation suggests that the suggested solution can
achieve a substantial improvement in availability, compared
to traditional, static redundancy strategies, and that tuning the
adopted degree of redundancy to the actual observed
disturbances allows unnecessary resource expenditure to be
reduced, therefore enhancing cost-effectiveness.
A Formal Model and an Algorithm for Generating the Permutations of a MultisetVincenzo De Florio
This paper may be considered as a mathematical divertissement as well as a didactical tool for
undergraduate students in a universitary course on algorithms and computation. The well-known problem of
generating the permutations of a multiset of marks is considered. We define a formal model and an abstract
machine (an extended Turing machine). Then we write an algorithm to compute on that machine the successor
of a given permutation in the lexicographically ordered set of permutations of a multiset. Within the model we
analyze the algorithm, prove its correctness, and show that the algorithm solves the above problem. Then we
describe a slight modification of the algorithm and we analyze in which cases it may result in an improvement of
execution times.
This paper, the ideas in it, and its realization are the work of the first author only.
Essentials of Automations: The Art of Triggers and Actions in FMESafe Software
In this second installment of our Essentials of Automations webinar series, we’ll explore the landscape of triggers and actions, guiding you through the nuances of authoring and adapting workspaces for seamless automations. Gain an understanding of the full spectrum of triggers and actions available in FME, empowering you to enhance your workspaces for efficient automation.
We’ll kick things off by showcasing the most commonly used event-based triggers, introducing you to various automation workflows like manual triggers, schedules, directory watchers, and more. Plus, see how these elements play out in real scenarios.
Whether you’re tweaking your current setup or building from the ground up, this session will arm you with the tools and insights needed to transform your FME usage into a powerhouse of productivity. Join us to discover effective strategies that simplify complex processes, enhancing your productivity and transforming your data management practices with FME. Let’s turn complexity into clarity and make your workspaces work wonders!
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
zkStudyClub - Reef: Fast Succinct Non-Interactive Zero-Knowledge Regex ProofsAlex Pruden
This paper presents Reef, a system for generating publicly verifiable succinct non-interactive zero-knowledge proofs that a committed document matches or does not match a regular expression. We describe applications such as proving the strength of passwords, the provenance of email despite redactions, the validity of oblivious DNS queries, and the existence of mutations in DNA. Reef supports the Perl Compatible Regular Expression syntax, including wildcards, alternation, ranges, capture groups, Kleene star, negations, and lookarounds. Reef introduces a new type of automata, Skipping Alternating Finite Automata (SAFA), that skips irrelevant parts of a document when producing proofs without undermining soundness, and instantiates SAFA with a lookup argument. Our experimental evaluation confirms that Reef can generate proofs for documents with 32M characters; the proofs are small and cheap to verify (under a second).
Paper: https://eprint.iacr.org/2023/1886
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
Generative AI Deep Dive: Advancing from Proof of Concept to ProductionAggregage
Join Maher Hanafi, VP of Engineering at Betterworks, in this new session where he'll share a practical framework to transform Gen AI prototypes into impactful products! He'll delve into the complexities of data collection and management, model selection and optimization, and ensuring security, scalability, and responsible use.
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
Enhancing Performance with Globus and the Science DMZGlobus
ESnet has led the way in helping national facilities—and many other institutions in the research community—configure Science DMZs and troubleshoot network issues to maximize data transfer performance. In this talk we will present a summary of approaches and tips for getting the most out of your network infrastructure using Globus Connect Server.
FIDO Alliance Osaka Seminar: Passkeys at Amazon.pdf
Reflective and Refractive Variables: A Model for Effective and Maintainable Adaptive-and-Dependable Software
1. Reflective and Refractive Variables: A Model for Effective and
Maintainable Adaptive-and-Dependable Software
Vincenzo De Florio, Chris Blondia
University of Antwerp
Department of Mathematics and Computer Science
Performance Analysis of Telecommunication Systems group
Middelheimlaan 1, 2020 Antwerp, Belgium
Interdisciplinary institute for BroadBand Technology
Gaston Crommenlaan 8, 9050 Ghent-Ledeberg, Belgium
Abstract
the bare machine up to the application. Problems of
this type include e.g. fault-tolerance, cross-layer signaling, or adaptability [9]. We can observe that wherever there is a need for flexibility, performance, quality
trade-offs, or security and co-operation, there exists
a need to monitor and adjust parameters across the
whole of the system layers. Much more than this, there
exist a need to do so in an as much as possible simple
way, from both an architectural and the user points
of view. This means that the architectural strategy
must be simple and that the way to express the solutions must be straightforward. To date, several clever
architectural strategies to solve those problems exist.
Just to name a few, the energy-performance manager
of IMEC [2] or the network-status of Mobiman [3] provide interesting architectures to reach effective crosslayer optimization. In both the mentioned approaches,
though, no solution is envisaged to the problem of the
optimal expression of cross-layered adaptations. For instance, both the above mentioned approaches require
ad hoc versions of the protocol layers, versions that explicitly make use of the network status. Each layer,
to be compliant to these models, must endorse logics
to take actions making use of the of the information
kept in a network status database. This requires the
design of ad hoc software. In such software the two
concerns – the functional one, i.e. the layer function,
and the non-functional one, for cross layer adaptation
– are mixed and intertwined. A possible solution currently being investigated by other researchers is aspect
oriented computing [8, 1], which requires the use of custom programming languages and complex tools. We
propose a simpler, language independent solution that
we call reflective and refractive variables (in short, RR
vars). In the following we describe our approach in
We propose a simple and effective tool for the expression of tasks such as cross-layer optimization strategies
or sensors-related applications. The approach is based
on what we refer to as “reflective and refractive variables”. Both types of variables are associated with external entities, e.g. sensors or actuators. A reflective
variable is a volatile variable, that is, a variable that
might be concurrently modified by multiple threads. A
library of threads is made available, each of which interfaces a set of sensors and continuously update the value
of a corresponding set of sensors. One such thread is
“cpu”, which exports the current level of usage of the
local CPU as an integer between 0 and 100. This integer is reflected into the integer reflective variable cpu.
A refractive variable is a reflective variable that can be
modified. Each modification is caught and interpreted
as a request to change the value of an actuator. For
instance, setting variable “tcp sendrate” would request
a cross-layer adjustment to the thread interfacing the
local TCP layer entity. This allows express in an easy
way complex operations in the application layer of any
programming language, e.g. plain old C. We describe
our translator and the work we are carrying out within
PATS to build simple and powerful libraries of scripts
based on reflective and refractive variables, including
robotics applications and RFID tags processing.
1
Introduction
As well known, a number of problems require solutions that involve the whole of the system layers, from
1
2. terface the cpu and the TCP external devices. Figure
3 shows this simple code in action on our development
platform—a Pentium-M laptop running Windows XP
and the Cygwin tools.
We observe that through the RR var model the design complexity is partitioned into two well defined and
separated components: the code to interface external
devices is specified “elsewhere” (Sect.3 describes where
and how) while the functional code is specified in a familiar way, in this case as a C code reading and writing
integer variables.
The result is a structured model to express tasks
such as cross-layered optimization, adaptive or faulttolerant computing in an elegant, non intrusive, and
cost-effective way. Such model is characterized by
strong separation of design concerns, for the functional strategies are not to be specified aside with
the layer functions; only instrumentation is required,
and this can be done once and for all. This prevents spaghetti-like coding for both the functional and
the non-functional aspects, and translates in enhanced
maintainability and enhanced efficiency.
The RR var model provides the designer also with
another attribute: a variable, be it an RR var or a
“common” one, can be tagged as being “redundant”.
Redundant variables are variables whose contents get
replicated several times so as to protect them from
memory faults. Writing a redundant variable means
writing a number of replicas, either located strategically1 on the same processing node or on remote
nodes—when available and the extra overhead be allowed. Reading from a redundant variable actually
translates in reading from each of its cells and performing majority voting. The result of this process is monitored by a special device, that we call Redundance.
Redundance measures the amount of votes that differ
from the majority vote, and uses this as a measure of
the disturbance in the surrounding environment. Under normal situation, Redundance triplicates the memory cells of redundant variables. This corresponds to
tolerating up to one memory fault in the cells associated to a redundant variable. Under more critical
situations, the amount of redundancy should change.
This is what actually happens: the component that
manages redundant variables declares the integer reflective variable “ref t int redundance”. The latter is
set asynchronously by the Redundance device, which
adjusts the corresponding memory cells2 with a number representing the ideal degree of redundancy with
Figure 1. A simple example of the use of RR vars.
Sect.2 and we show how we implemented it in Sect.3.
An analysis of current and possible uses of RR vars in
fields such as robotics, sensor networks, and RFID applications, is presented in Sect.4. Section 5 concludes
this work with a description of our future plans involving RR vars.
2
Reflective, Refractive and Redundant Variables
The idea behind RR vars is to use memory access
as an abstraction to perform concealed tasks. RR vars
are volatile variables whose identifier links them with
an external device, such as a sensor, or an RFID, or an
actuator. In reflective variables, memory cells get asynchronously updated by service threads that interface
those external devices. We use the well-known concept
of reflection because those variables “reflect” the values measured by those devices. In refractive variables,
on the contrary, write requests trigger a request to update an external parameter, such as the data rate of
the local TCP protocol entity or the amount of redundancy to be used in transmissions. We use to say that
write accesses “refract” (that is, get redirected [7]) onto
corresponding external devices.
The RR var model does not require any special language: Figure 1 is an example in the C language. The
portrayed program declares two variables: “cpu”, a reflective integer, which reports the current level of usage of the local CPU as an integer number between 0
and 100, and “tcpTxRate”, a reflective and refractive
integer, which reports and sets the send rate parameter of the TCP layer. The code periodically queries
the CPU usage and, when that reaches a value greater
than 90%, it requests to change the TCP send rate.
Note that the only non standard C construct is attribute “Ref t”, which specifies that a corresponding
declaration is reflective or refractive or both. Through
a translation process, discussed in Sect.3, this code is
instrumented so as to include the logics required to in-
1 Strategically means here that the redundant cells are allocated in such a way as to tolerate possible burst errors, affecting
contiguous memory cells.
2 Not surprisingly enough, variable “redundance” is indeed. . . redundant.
2
3. Figure 2. An excerpt from the execution of the code in Fig.2.
and one server-side to monitor and drive the external
devices. To explain this process we consider Fig.5, an
excerpt from the translation of the code in Fig.4. Let
us review the resulting code in more detail (please note
that item x in the following list refer to lines tagged as
“// x” in the code):
respect to the current degree of disturbances.
The RR var model does not support only cross-layer
optimization—in general, it provides an applicationlayer construct to manage feedback loops.
Feedback loops (see Fig.3)—a well known concept
from system theory are ideal forms to shape our systems so as to be adaptive-and-dependable [10]. Such
property is an important pre-requisite for the welfare
of our computer-dominated societies and economies: in
the cited paper Van Roy explains their relevance to
future software design. RR vars provide a straightforward syntactical structure and software architecture for
the expression of feedback loops. We use this structure,
e.g., to implement redundant variables. The main advantage in this case is that, instead of taking a design
decision once and for all, we let a system parameter
change as needed, zeroing in on the optimum. The use
of RR vars simplifies the design of our solution, which
also enhances maintainability. But probably the most
important consequence is that our solution does not assume a fixed, immutable fault model, but lets it change
with the actual faults being experienced.
Figure 4 shows how simple it is using a redundant
variable: no syntactic differences can be noticed. The
required logic is “hidden” in the translation process.
3
1. First the translator removes the occurrences of attributes “ref t” and “redundant”.
2. Then it performs a few calls to function “aopen”.
This is to open the associative arrays “reflex” and
“rtype”. As well known, an associative array generalizes the concept of array so as to allow addressing items by non-integer indexes. The arguments
to “aopen” are functions similar to “strcmp”, from
the C standard library, which are used to compare
index objects. The idea is that these data structures create links between the name of variables
and some useful information (see below).
3. There follow a number of “awrites”, i.e., we create associations between variables identifiers and
two numbers: the corresponding variables’ address
and an internal code representing its type and attributes.
4. Then “Server”, the thread responsible to interface
the external devices, is spawned.
Implementation
5. Besides a write access into refractive variable tcpTxRate, the translator places a call to function
“CalltcpTxRate”. In general, after a call to refractive variable v, the call “Callv(&v)” is produced.
The core of the RR vars architecture is a parser that
translates the input source code into two source files,
one with an augmented version of the original code
3
4. Figure 3. General structure of feedback loops (picture from [10]).
Figure 4. Redundant variables.
4
6. Similarly, a write access to redundant variable w,
of type t, is followed by a call to “RedundantAssign t(&w)”.
Problem Solving with RR Vars
We are in the process of making use of RR vars
in several real-life applications—we plan to report on
these use cases in further papers. In the meanwhile we
report herein on possible contexts where RR vars could
provide effective and low-cost solutions.
7. Finally, reading from redundant variable w, of type
t, is translated into a call to function “RedundantRead t(&w)”.
It is the responsibility of the designer to make
sure that proper code for functions “Callv(&v)” is
produced. Functions “RedundantAssign t(&w)” and
“RedundantRead t(&w)” are automatically generated
through a template-like approach—the former performs a redundant write, the latter a redundant read
plus majority voting. For voting, an approach similar
to that in [5] is followed. Associative arrays are managed through class ASSOC [4].
As already mentioned, the “Server” thread is the
code responsible to monitor and interface the external devices. Its algorithm is quite simple (see Fig.6):
the code continuously waits for a sensor update (lines
tagged with “// 1”), then retrieves the address and
type of the corresponding reflective variable (in “//
2”) and finally updates that variable (“// 3”).
The complexity to interface external devices is
charged to function “getValue”, we show an excerpt
of which in Fig.7. The core of “getValue” is function
“cpu”, which returns the amount of CPU currently being used.
4.1
Concurrency
As cleverly explained e.g. by Gates in [6], a well
known challenge in robotics is concurrency, defined in
the cited paper as “how to simultaneously handle all
the data coming in from multiple sensors and send the
appropriate commands to the robot’s motors”. The
conventional approach, i.e., making use of a long loop
that first reads all the data from the sensors, then processes the input and finally controls the robot is not
adequate enough. Because of this, the robot control
could be using stale values, which could bring to disastrous consequences. As Gates mentions in the cited paper, this is a scenario that applies not only to robotics
but also to all those fields such as distributed and parallel computing where data and control often need to
be effectively orchestrated under strict real-time constraints. “To fully exploit the power of processors
working in parallel, the new software must deal with
the problem of concurrency”, Gate says. We believe
4
5. Figure 5. Abridged version of the main function of the translated code.
Figure 6. The Server code.
Figure 7. Function getValue interfaces all the external devices that are connected to RR vars.
5
6. used to realize redundant data structures. As well
known, redundancy is a key property in fault-tolerance.
The Shannon teorem teaches us that through any unreliable channel it is possible to send data reliably by
using a proper degree of redundancy. This famous result can be read out in a different way: for each degree of unreliability, there is a minimum level of redundancy that can be used to tolerate any fault. Our
approach uses RR vars to attune the degree of redundancy required to ensure data integrity to the actual
faults being experienced by the system. This provides
an example of adaptive fault-tolerant software.
RR vars can be used to express problems in crosslayer optimization, but also in contexts where concurrency calls for expressive software structures, e.g.
robotics. Localization problems could also be solved
through a very simple scheme. Within PATS we are
now further improving our model and tools and designing a few simple and powerful libraries of scripts
based on reflective and refractive variables.
Figure 8. RR var to localize objects with RFID tags on
them.
an approach like RR vars can be an effective syntactic
structure for that: a control loop using reflective variables, for instance, would not need to specify a reading
order for the input variables, which are updated asynchronously, as new values need to replace old ones.
4.2
Localizing Hidden Assets
We are currently extending our translator so as to
allow writing programs such as the one in Fig.8.
At first sight the program may sound meaningless,
as it only declares a function and an RR var, “rfid”, and
does not seem to perform any useful action. “Behind
the lines”—a nice feature offered by translators—what
happens is that surrounding RFID tags reflect their
content onto reflective variable “rfid”. Data stored into
that variable is compared with the initialization value
(in this case, an ISBN number). In case of a match,
function “beep” is called.
Now imagine running this code onto your PDA while
walking through the lanes of a large library such as
the Vatican Library in search for a “lost” or misplaced
book. When in reach of the searched item, the PDA
starts beeping3 . Or imagine that, thanks to international regulations, all “companies” building antipersonnel mines be obliged by law to embed RFID tags into
their “products”. When activated, these tags and a
program as simple as the one in Fig.8 could easily prevent dreadful events that continuously devastate the
lives of too many a human being.
5
References
[1] J. Bon´r. AspectWerkz - dynamic AOP for Java. In
e
Proceedings of AOSD 2004, March 2004.
[2] B. Bougard, G. Lenoir, W. Eberle. A new approach
to dynamically trade off performance and energy consumption in wireless communication systems. In Proc.
of IEEE SiPS, Aug. 2003.
[3] M. Conti, G. Maselli, G. Turi, S. Giordano. Crosslayering in mobile ad hoc network design. Computer,
37(2):48–51, Feb. 2004.
[4] V. De Florio. Array associativi, linguaggio C e programmazione CGI. DEV., (27), Feb. 1996.
[5] V. De Florio, G. Deconinck, R. Lauwereins. Software tool combining fault masking with user-defined
recovery strategies.
IEE Proceedings – Software,
145(6):203–211, Dec. 1998.
[6] B. Gates. A robot in every home. Scientific American,
Jan. 2007.
[7] Institute for Telecommunication Sciences. Telecommunication standard terms. Retrieved on Jan. 31,
2007 from www.babylon.com/dictionary/4197/Telecommunication Standard Terms Dictionary.
[8] G. Kiczales, J. Lamping, A. Mendhekar, C. Maeda,
C. Videira Lopes, J.-M. Loingtier, J. Irwin. Aspectoriented programming. In ECOOP’97, Lecture Notes
in Computer Science, vol. 1241, Finland, June 1997.
Springer, Berlin.
[9] J. H. Saltzer, D. P. Reed, and D. D. Clark. End-toend arguments in system design. ACM Trans. Comp.
Sys., 2(4):277–288, 1984.
[10] P. Van Roy. Self management and the future of
software design. Elec. Notes in Theor. Comp. Sci.
(www.elsevier.com/locate/entcs), 2006.
Conclusions
We introduced a translation system that allows making use of reflection in a standard programming language such as C. The same translator supports “refraction”, that is the control of external devices through
simple memory write accesses. These two features are
3 The tomes of the Vatican library have been recently
equipped with RFID tags.
6