85 research outputs found
Security and Privacy for Modern Wireless Communication Systems
The aim of this reprint focuses on the latest protocol research, software/hardware development and implementation, and system architecture design in addressing emerging security and privacy issues for modern wireless communication networks. Relevant topics include, but are not limited to, the following: deep-learning-based security and privacy design; covert communications; information-theoretical foundations for advanced security and privacy techniques; lightweight cryptography for power constrained networks; physical layer key generation; prototypes and testbeds for security and privacy solutions; encryption and decryption algorithm for low-latency constrained networks; security protocols for modern wireless communication networks; network intrusion detection; physical layer design with security consideration; anonymity in data transmission; vulnerabilities in security and privacy in modern wireless communication networks; challenges of security and privacy in node–edge–cloud computation; security and privacy design for low-power wide-area IoT networks; security and privacy design for vehicle networks; security and privacy design for underwater communications networks
Operational Research: methods and applications
This is the final version. Available on open access from Taylor & Francis via the DOI in this recordThroughout its history, Operational Research has evolved to include methods, models and algorithms that have been applied to a wide range of contexts. This encyclopedic article consists of two main sections: methods and applications. The first summarises the up-to-date knowledge and provides an overview of the state-of-the-art methods and key developments in the various subdomains of the field. The second offers a wide-ranging list of areas where Operational Research has been applied. The article is meant to be read in a nonlinear fashion and used as a point of reference by a diverse pool of readers: academics, researchers, students, and practitioners. The entries within the methods and applications sections are presented in alphabetical order. The authors dedicate this paper to the 2023 Turkey/Syria earthquake victims. We sincerely hope that advances in OR will play a role towards minimising the pain and suffering caused by this and future catastrophes
Operational research:methods and applications
Throughout its history, Operational Research has evolved to include a variety of methods, models and algorithms that have been applied to a diverse and wide range of contexts. This encyclopedic article consists of two main sections: methods and applications. The first aims to summarise the up-to-date knowledge and provide an overview of the state-of-the-art methods and key developments in the various subdomains of the field. The second offers a wide-ranging list of areas where Operational Research has been applied. The article is meant to be read in a nonlinear fashion. It should be used as a point of reference or first-port-of-call for a diverse pool of readers: academics, researchers, students, and practitioners. The entries within the methods and applications sections are presented in alphabetical order
Models, methods, and tools for developing MMOG backends on commodity clouds
Online multiplayer games have grown to unprecedented scales, attracting millions of players
worldwide. The revenue from this industry has already eclipsed well-established entertainment
industries like music and films and is expected to continue its rapid growth in the future.
Massively Multiplayer Online Games (MMOGs) have also been extensively used in research
studies and education, further motivating the need to improve their development process.
The development of resource-intensive, distributed, real-time applications like MMOG backends
involves a variety of challenges. Past research has primarily focused on the development and
deployment of MMOG backends on dedicated infrastructures such as on-premise data centers
and private clouds, which provide more flexibility but are expensive and hard to set up and
maintain. A limited set of works has also focused on utilizing the Infrastructure-as-a-Service
(IaaS) layer of public clouds to deploy MMOG backends. These clouds can offer various advantages
like a lower barrier to entry, a larger set of resources, etc. but lack resource elasticity,
standardization, and focus on development effort, from which MMOG backends can greatly
benefit.
Meanwhile, other research has also focused on solving various problems related to consistency,
performance, and scalability. Despite major advancements in these areas, there is no standardized
development methodology to facilitate these features and assimilate the development of
MMOG backends on commodity clouds. This thesis is motivated by the results of a systematic
mapping study that identifies a gap in research, evident from the fact that only a handful
of studies have explored the possibility of utilizing serverless environments within commodity
clouds to host these types of backends. These studies are mostly vision papers and do
not provide any novel contributions in terms of methods of development or detailed analyses
of how such systems could be developed. Using the knowledge gathered from this mapping
study, several hypotheses are proposed and a set of technical challenges is identified, guiding
the development of a new methodology.
The peculiarities of MMOG backends have so far constrained their development and deployment
on commodity clouds despite rapid advancements in technology. To explore whether such
environments are viable options, a feasibility study is conducted with a minimalistic MMOG
prototype to evaluate a limited set of public clouds in terms of hosting MMOG backends. Foli
lowing encouraging results from this study, this thesis first motivates toward and then presents
a set of models, methods, and tools with which scalable MMOG backends can be developed
for and deployed on commodity clouds. These are encapsulated into a software development
framework called Athlos which allows software engineers to leverage the proposed development
methodology to rapidly create MMOG backend prototypes that utilize the resources of
these clouds to attain scalable states and runtimes. The proposed approach is based on a dynamic
model which aims to abstract the data requirements and relationships of many types of
MMOGs. Based on this model, several methods are outlined that aim to solve various problems
and challenges related to the development of MMOG backends, mainly in terms of performance
and scalability. Using a modular software architecture, and standardization in common development
areas, the proposed framework aims to improve and expedite the development process
leading to higher-quality MMOG backends and a lower time to market. The models and methods
proposed in this approach can be utilized through various tools during the development
lifecycle.
The proposed development framework is evaluated qualitatively and quantitatively. The thesis
presents three case study MMOG backend prototypes that validate the suitability of the proposed
approach. These case studies also provide a proof of concept and are subsequently used
to further evaluate the framework. The propositions in this thesis are assessed with respect to
the performance, scalability, development effort, and code maintainability of MMOG backends
developed using the Athlos framework, using a variety of methods such as small and large-scale
simulations and more targeted experimental setups. The results of these experiments uncover
useful information about the behavior of MMOG backends. In addition, they provide evidence
that MMOG backends developed using the proposed methodology and hosted on serverless
environments can: (a) support a very high number of simultaneous players under a given latency
threshold, (b) elastically scale both in terms of processing power and memory capacity
and (c) significantly reduce the amount of development effort. The results also show that this
methodology can accelerate the development of high-performance, distributed, real-time applications
like MMOG backends, while also exposing the limitations of Athlos in terms of code
maintainability.
Finally, the thesis provides a reflection on the research objectives, considerations on the hypotheses
and technical challenges, and outlines plans for future work in this domain
Performance of the Gittins Policy in the G/G/1 and G/G/k, With and Without Setup Times
How should we schedule jobs to minimize mean queue length? In the preemptive
M/G/1 queue, we know the optimal policy is the Gittins policy, which uses any
available information about jobs' remaining service times to dynamically
prioritize jobs. For models more complex than the M/G/1, optimal scheduling is
generally intractable. This leads us to ask: beyond the M/G/1, does Gittins
still perform well?
Recent results indicate that Gittins performs well in the M/G/k, meaning that
its additive suboptimality gap is bounded by an expression which is negligible
in heavy traffic. But allowing multiple servers is just one way to extend the
M/G/1, and most other extensions remain open. Does Gittins still perform well
with non-Poisson arrival processes? Or if servers require setup times when
transitioning from idle to busy?
In this paper, we give the first analysis of the Gittins policy that can
handle any combination of (a) multiple servers, (b) non-Poisson arrivals, and
(c) setup times. Our results thus cover the G/G/1 and G/G/k, with and without
setup times, bounding Gittins's suboptimality gap in each case. Each of (a),
(b), and (c) adds a term to our bound, but all the terms are negligible in
heavy traffic, thus implying Gittins's heavy-traffic optimality in all the
systems we consider. Another consequence of our results is that Gittins is
optimal in the M/G/1 with setup times at all loads.Comment: 41 page
Operational Research: Methods and Applications
Throughout its history, Operational Research has evolved to include a variety of methods, models and algorithms that have been applied to a diverse and wide range of contexts. This encyclopedic article consists of two main sections: methods and applications. The first aims to summarise the up-to-date knowledge and provide an overview of the state-of-the-art methods and key developments in the various subdomains of the field. The second offers a wide-ranging list of areas where Operational Research has been applied. The article is meant to be read in a nonlinear fashion. It should be used as a point of reference or first-port-of-call for a diverse pool of readers: academics, researchers, students, and practitioners. The entries within the methods and applications sections are presented in alphabetical order. The authors dedicate this paper to the 2023 Turkey/Syria earthquake victims. We sincerely hope that advances in OR will play a role towards minimising the pain and suffering caused by this and future catastrophes
Operational Research: Methods and Applications
Throughout its history, Operational Research has evolved to include a variety of methods, models and algorithms that have been applied to a diverse and wide range of contexts. This encyclopedic article consists of two main sections: methods and applications. The first aims to summarise the up-to-date knowledge and provide an overview of the state-of-the-art methods and key developments in the various subdomains of the field. The second offers a wide-ranging list of areas where Operational Research has been applied. The article is meant to be read in a nonlinear fashion. It should be used as a point of reference or first-port-of-call for a diverse pool of readers: academics, researchers, students, and practitioners. The entries within the methods and applications sections are presented in alphabetical order
The impact of disruptive technology on the manufacturing process, and productivity, in an advanced manufacturing environment.
Doctoral Degree. University of KwaZulu-Natal, Durban.Disruptive technology plays a critical role in the performance of mechatronic systems in an advanced manufacturing environment. Robots were used to perform pick and place task in a virtual manufacturing environment. Newton-Raphson model, renewal theorem and queuing theory were used to model the disruptive technology and develop decision-making algorithms in an advanced process. The motion of the conveyor belt system starved modeled and simulated to determine suitable design parameters that were compatible with the tasks of the pick and place robot.
MATLAB and Engineering Equation Solver (EES) were used to determine static solutions and simulated solutions to the pick and place problem in the advanced manufacturing process. The results from the simulations were used to develop suitable task-dependent operational conditions in the advanced manufacturing environment. The simulation results were used to determine the optimal conveyor speeds required for the robotic tasks. Comparing the throughput rate of the developed system with the simulated system indicated that optimal productivity was achieved when the decision-making algorithms were implemented at the early stages of the manufacturing process
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