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IEEE International Workshop on Information Forensics and Security (WIFS)

作者： Niels Zeilemaker Zekeriya Erkin Paolo Palmieri Johan Pouwelse Parallel and Distributed Systems Group Delft University of Technology Delft The Netherlands Information Security and Privacy Lab Delft University of Technology Delft The Netherlands

Searching a Peer-to-Peer (P2P) network without using a central index has been widely investigated but proved to be very difficult. Various strategies have been proposed, however no practical solution to date also addr... 详细信息

关键词： Protocols Cryptography

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DMSS: A Dynamic Memory Scheduling System in Server Consolidation Environments

DMSS: A Dynamic Memory Scheduling System in Server Consolida...

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IEEE International Symposium on Object/Component/Service-Oriented Real-Time distributed Computing Workshops (ISORCW)

作者： Lanzheng Liu Rui Chu Yongchun Zhu Pengfei Zhang Liufeng Wang National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China Systems and Technology Group IBM China Beijing China

As the foundation of cloud computing, Server consolidation allows multiple computer infrastructures running as virtual machines in a single physical node. It improves the utilization of most kinds of resource but memory under x86 architecture. Because of inaccurate memory usage estimate and the lack of memory resource management, there is much service performance degradation in data centers, even though they have occupied a large amount of memory. Furthermore, memory becomes insufficient for a physical server when a lot of virtual machines depend on it. In order to improve this, we present a dynamic memory scheduling system called DMSS, which can manage memory resources in server consolidation environments and allocate memory among virtual machines on demand. We have designed and implemented the corresponding memory scheduling policy based on Xen virtualization platform to enhance memory efficiency and achieve service level agreement. The benchmark shows that DMSS can make an accurate and rapid response to memory changes and save more than 30% physical memory with less than 5% performance degradation. DMSS actually brings in economic benefits to cloud service providers because more virtual machines can be accommodated at lower costs.

关键词： Memory management Virtual machine monitors Monitoring Resource management Servers Dynamic scheduling Degradation

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BitTorrent's dilemma: Enhancing reciprocity or reducing inequity

BitTorrent's dilemma: Enhancing reciprocity or reducing ineq...

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Consumer Communications and Networking Conference, CCNC IEEE

作者： Adele L. Jia Lucia D'Acunto Michel Meulpolder Johan A. Pouwelse Dick H. J. Epema Parallel and Distributed Systems Group Department of Computer Science Delft University of Technology The Netherlands Technische Universiteit Delft Delft Zuid-Holland NL

Enhancing reciprocity has been one of the primary motivations for the design of incentive policies in BitTorrent-like P2P systems. Reciprocity implies that peers need to contribute their bandwidth to other peers if they want to receive bandwidth in return. However, the over-provisioning that characterizes today's BitTorrent communities and the development of many next-generation P2P systems with real-time constraints (e.g., for live and on-demand streaming) suggest that more effort can be devoted to reducing the inequity (i.e., the difference of service received) among peers, rather than only enhancing reciprocity. Inspired by this observation, in this work we analyze in detail several incentive mechanisms that are used in BitTorrent systems, and explore several strategies that influence the balance between reciprocity and equity. Our study shows that (i) reducing inequity leads to a better overall system performance, and (ii) the behavior of seeders (i.e., peers that hold a complete copy of the file and upload it for free) influences whether reciprocity is enhanced or inequity reduced.

关键词： Thin film transistors Bandwidth Analytical models Peer to peer computing Protocols Channel allocation Steady-state

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Evaluation of Bfloat16, Posit, and Takum Arithmetics in Sparse Linear Solvers

arXiv

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arXiv 2024年

作者： Hunhold, Laslo Quinlan, James Parallel and Distributed Systems Group University of Cologne Cologne Germany Department of Computer Science University of Southern Maine Portland ME United States

Solving sparse linear systems lies at the core of numerous computational applications. Consequently, understanding the performance of recently proposed alternatives to the established IEEE 754 floating-point numbers, such as bfloat16 and the tapered-precision posit and takum machine number formats, is of significant interest. This paper examines these formats in the context of widely used solvers, namely LU, QR, and GMRES, with incomplete LU preconditioning and mixed precision iterative refinement (MPIR). This contrasts with the prevailing emphasis on designing specialized algorithms tailored to new arithmetic formats. This paper presents an extensive and unprecedented evaluation based on the SuiteSparse Matrix Collection—a dataset of real-world matrices with diverse sizes and condition numbers. A key contribution is the faithful reproduction of SuiteSparse’s UMFPACK multifrontal LU factorization and SPQR multifrontal QR factorization for machine number formats beyond single and double-precision IEEE 754. Tapered-precision posit and takum formats show better accuracy in direct solvers and reduced iteration counts in indirect solvers. Takum arithmetic, in particular, exhibits exceptional stability, even at low precision. © 2024, CC BY.

关键词： Iterative methods

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On the Potential of NoC Virtualization for Multicore Chips

On the Potential of NoC Virtualization for Multicore Chips

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International Conference on Complex, Intelligent and Software Intensive systems, CISIS

作者： Jose Flich Samuel Rodrigo Jose Duato Thomas Sødring Åshild Grønstad Solheim Tor Skeie Olav Lysne Parallel Architectures Group Technical University of Valencia Spain Networks and Distributed Systems Simula Research Laboratory Norway Department of Informatics University of Oslo Norway

As the end of Moores-law is on the horizon, power becomes a limiting factor to continuous increases in performance gains for single-core processors. Processor engineers have shifted to the multicore paradigm and many-core processors are a reality. Within the context of these multi-core chips, three key metrics point themselves out as being of major importance, performance, fault-tolerance (including yield), and power consumption. A solution that optimizes all three of these metrics is challenging. As the number of cores increases the importance of the interconnection network-on-chip (NoC) grows as well, and chip designers should aim to optimize these three key metrics in the NoC context as well. In this paper we identify and discuss the main properties that a NoC must exhibit in order to enable such optimizations. In particular, we propose the use of virtualization techniques at the NoC level. AS a major finding, we identify the implementation of routing algorithms to become a key design parameter in order to achieve an effective virtualization of the chip should also supporting broadcast within the virtualized context. The intention behind this paper is for it to serve as a position paper on the topic of virtualization for NoC and the challenges that should be met at the routing layer in order to maximize performance, fault-tolerance and power consumption in multicore chips.

关键词： Magnetic cores Routing Resource management Power demand Topology Fault tolerance Fault tolerant systems

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Proactive Adaptation of Data Rate in Mobile LoRa-Based IoT Devices Using Machine Learning

Proactive Adaptation of Data Rate in Mobile LoRa-Based IoT D...

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IEEE Conference on Vehicular Technology (VTC)

作者： Laura Acosta-Garcia Juan Aznar-Poveda Antonio-Javier Garcia-Sanchez Joan Garcia-Haro Thomas Fahringer Department of Information and Communication Technologies Universidad Politécnica de Cartagena Cartagena Spain Distributed and Parallel Systems Group University of Innsbruck Innsbruck Austria

ISBN: (数字)9798350387414

ISBN: (纸本)9798350387421

Even though the initial design of LoRa did not specifically aim at provisioning mobile devices, onboard IoT devices are paving the way for safer, more efficient, and ultimately, autonomous transportation. The LoRaWAN Adaptive Data Rate (ADR) mechanism enables the minimization of energy consumption and the optimization of data rates and airtime values. However, it has been demonstrated to have limited adaptability in mobile devices. In this paper, we propose a proactive ADR mechanism for LoRaWAN based on trajectory estimation and well-known machine-learning methods used to forecast the signal-to-noise ratio (SNR). This enables the efficient selection of the most suitable transmission parameters beforehand. We compare our approach with existing mechanisms in a realistic simulator and several urban environments. Results prove that our method achieves a proper balance between minimizing energy consumption and satisfying performance constraints over time even in highly dynamic and unpredictable environments.

关键词： Performance evaluation Energy consumption Vehicular and wireless technologies Heuristic algorithms LoRaWAN Machine learning Mobile handsets

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The Design and Optimization of Memory Ballooning in SEV Confidential Virtual Machines

The Design and Optimization of Memory Ballooning in SEV Conf...

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IEEE International Conference on Joint Cloud Computing (JCC)

作者： Chang Deng Zheyun Shen Dingji Li Zeyu Mi Yubin Xia The 32nd Research Institute of China Electronics Technology Group Corporation China Institute of Parallel and Distributed Systems Shanghai Jiao Tong University China

ISBN: (数字)9798350387339

ISBN: (纸本)9798350387346

With the popularity of confidential computing, confidential virtual machines (CVMs) have been widely adopted and they guarantee strong security by hardware. However, there still exist some problems in memory management in CVMs. Since private memory pages of CVMs are encrypted and cannot be accessed by hypervisors, existing CVMs employ static page management to avoid crashes due to the relocation of encrypted memory pages, leading cloud platforms managing CVMs to face more severe memory management pressures than before. Memory ballooning, as an efficient, flexible, and highly compatible memory management mechanism in virtualization, is not available in CVMs based on SEV (Secure Encrypted Virtualization). In this paper, we analyze the design of SEV CVMs and memory ballooning, and enable memory ballooning on SEV CVMs by substituting static page management with dynamic page management and addressing communication issues between the guest frontend and the host backend. Besides, we propose three performance optimization strategies for memory ballooning on SEV CVMs, including asynchronous reclaiming on the host side, an additional shadow vCPU on the guest side, and accelerating cache flushing operations in the host kernel. Experiments show that the time cost of reclaiming memory from SEV CVMs by memory ballooning can be reduced by up to 38 times and up to 55% overhead caused by delaying reclamation in real-world applications like MYSQL can be eliminated.

关键词： Cloud computing Virtual machine monitors Costs Memory management Hardware Computer crashes Cryptography

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Multi Radio Diversity for Satellite-Terrestrial Mobile Communications

Multi Radio Diversity for Satellite-Terrestrial Mobile Commu...

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4th International Conference on Circuits and systems for Communications (ICCSC 2008), vol.2

作者： A. A. Khan M. Adda T. A. Khan Faculty of Technology University of Portsmouth UK Principle Lecturer at the Faculty of Technology University of Portsmouth UK Faculty of Technology Parallel and Distributed Systems Research Group Signals & Systems Ltd Rawalpindi Pakistan

This paper presents the study of the resource allocation problem in hybrid terrestrial and satellite mobile communication networks. The number of terrestrial and satellite mobile communication standards is increasing, as well as the number of users in the market. Efficient access allocation schemes not only aid network operators with better resource utilizations but also provide the users with better service times, specifically required in emergency/high load situations. The degree of internetworking in access allocation procedures varies from tight to very loose internetworking. In this paper we present a parallel Multi Radio Diversity (MRD) based access allocation scheme in a hybrid terrestrial-satellite network which through diversity gains, results in improved mean service time. The analysis is validated via dynamic system level simulation of a sub-urban area.

关键词： Access Allocation WiMAX S-UMTS HSDPA CRRM MRD

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Simulating Cyber Attacks and Designing Malware using Python 10

Simulating Cyber Attacks and Designing Malware using Python

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10th International Conference on Signal Processing and Integrated Networks, SPIN 2023

作者： Ankit, Akash Inder, Shubham Sharma, Anuj Johari, Rahul Vidyarthi, Deo Prakash University School of Information Communication and Technology Guru Gobind Singh Indraprastha University SWINGER: Security Wireless IoT Network Group of Engineering and Research Dwarka New Delhi110078 India MelbourneVIC3000 Australia Jawaharlal Nehru University Parallel and Distributed System Lab School of Computer and Systems Sciences New Delhi110067 India

ISBN: (纸本)9781665490993

In this Internet era, we have become heavily dependent on the World Wide Web and it has become a basic amenity for humans. A normal user can be trapped easily in this vicious web if not careful enough. It is a field that requires users to be on their toes every time they try to connect to this enormous interconnection of networks. Reports and Surveys have said that in the coming years, Cybercrime could become the biggest threat. In this proposed work, the authors have deployed applications and designed malware for the purpose of simulating various kinds of cyber-attacks so that they could study their effects & affects and ultimately devise solutions to resolve the vulnerabilities in a system. These applications included networking concepts & protocols and a software based keylogger which was developed with no malicious intent, but to analyse the architectural view or design of a malware and to study the stages of a malware attack like entry, distribution, exploitation, infection and execution. Efforts have been made to demonstrate spooting attacks with an idea of identifying vulnerabilities and security loopholes in a particular system that can be exploited by an attacker if not resolved within time. © 2023 IEEE.

关键词： Network security

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distributed environment for efficient virtual machine image management in federated Cloud architectures

Distributed environment for efficient virtual machine image ...

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作者： Kimovski, Dragi Marosi, Attila Gec, Sandi Saurabh, Nishant Kertesz, Attila Kecskemeti, Gabor Stankovski, Vlado Prodan, Radu Distributed and Parallel Systems Group University of Innsbruck Innsbruck Austria Hungarian Academy of Science Budapest Hungary Faculty of Civil and Geodetic Engineering University of Ljubljana Ljubljana Slovenia Faculty of Computer and Information Science University of Ljubljana Ljubljana Slovenia Liverpool John Moores University Liverpool United Kingdom University of Information Science and Technology Ohrid Macedonia

The use of virtual machines (VMs) in Cloud computing provides various benefits in the overall software engineering lifecycle. These include efficient elasticity mechanisms resulting in higher resource utilization and lower operational costs. The VMs as software artifacts are created using provider-specific templates, called virtual machine images (VMI), and are stored in proprietary or public repositories for further use. However, some technology-specific choices can limit the interoperability among various Cloud providers and bundle the VMIs with nonessential or redundant software packages, leading to increased storage size, prolonged VMI delivery, stagnant VMI instantiation, and ultimately vendor lock-in. To address these challenges, we present a set of novel functionalities and design approaches for efficient operation of distributed VMI repositories, specifically tailored for enabling (1) simplified creation of lightweight and size optimized VMIs tuned for specific application requirements;(2) multi-objective VMI repository optimization;and (3) efficient reasoning mechanism to help optimizing complex VMI operations. The evaluation results confirm that the presented approaches can enable VMI size reduction by up to 55%, while trimming the image creation time by 66%. Furthermore, the repository optimization algorithms can reduce the VMI delivery time by up to 51% and cut down the storage expenses by 3%. Moreover, by implementing replication strategies, the optimization algorithms can increase the system reliability by 74%. Copyright © 2017 John Wiley & Sons, Ltd.

关键词： Virtual machine

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