174 research outputs found
Advanced Radio Frequency Identification Design and Applications
Radio Frequency Identification (RFID) is a modern wireless data transmission and reception technique for applications including automatic identification, asset tracking and security surveillance. This book focuses on the advances in RFID tag antenna and ASIC design, novel chipless RFID tag design, security protocol enhancements along with some novel applications of RFID
IP-based virtual private networks and proportional quality of service differentiation
IP-based virtual private networks (VPNs) have the potential of delivering cost-effective, secure, and private network-like services. Having surveyed current enabling techniques, an overall picture of IP VPN implementations is presented.
In order to provision the equivalent quality of service (QoS) of legacy connection-oriented layer 2 VPNs (e.g., Frame Relay and ATM), IP VPNs have to overcome the intrinsically best effort characteristics of the Internet. Subsequently, a hierarchical QoS guarantee framework for IP VPNs is proposed, stitching together development progresses from recent research and engineering work.
To differentiate IP VPN QoS, the proportional QoS differentiation model, whose QoS specification granularity compromises that of IntServ and Diffserv, emerges as a potential solution. The investigation of its claimed capability of providing the predictable and controllable QoS differentiation is then conducted.
With respect to the loss rate differentiation, the packet shortage phenomenon shown in two classical proportional loss rate (PLR) dropping schemes is studied. On the pursuit of a feasible solution, the potential of compromising the system resource, that is, the buffer, is ruled out; instead, an enhanced debt-aware mechanism is suggested to relieve the negative effects of packet shortage. Simulation results show that debt-aware partially curbs the biased loss rate ratios, and improves the queueing delay performance as well.
With respect to the delay differentiation, the dynamic behavior of the average delay difference between successive classes is first analyzed, aiming to gain insights of system dynamics. Then, two classical delay differentiation mechanisms, that is,proportional average delay (PAD) and waiting time priority (WTP), are simulated and discussed. Based on observations on their differentiation performances over both short and long time periods, a combined delay differentiation (CDD) scheme is introduced. Simulations are utilized to validate this method.
Both loss and delay differentiations are based on a series of differentiation parameters. Though previous work on the selection of delay differentiation parameters has been presented, that of loss differentiation parameters mostly relied on network operators\u27 experience. A quantitative guideline, based on the principles of queueing and optimization, is then proposed to compute loss differentiation parameters. Aside from analysis, the new approach is substantiated by numerical results
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Logical partitioning of parallel system simulations
Simulation has been a fundamental tool to prototype, hypothesize, and evaluate
new ideas to continue improving system performance. However, increasing levels
of processor parallelism and heterogeneity have introduced additional
constraints when evaluating new designs. The work embodied in this dissertation
explores how to leverage novel ideas in simulator partitioning to improve
simulator speed and flexibility for simulating these new types of systems.
The contribution of this work includes the introduction of optimistic
partitioned simulation to improve parallelization, and the introduction of
warped partitioned simulation for improved flexibility. These ideas are refined
and demonstrated through the use of prototypes to demonstrate their benefits
compared to state-of-the-art approaches. By leveraging partitioning in a
structured manner, it is possible to design simulators that better address the
open challenges of parallel and heterogeneous systems design.Electrical and Computer Engineerin
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A Neural Signal Processor for Low-Latency Spike Inference
This thesis describes the development of a system that can assign identities to a population of single-units, in multi-electrode recordings, at single-spike resolution with low-latency. The system has two parts. The first is a Field-Programmable Gate Array (FPGA)-based Neural Signal Processor (NSP) that receives raw input and generates labelled spikes as output, a process referred to as real-time spike inference. The second is a piece of software (Spiketag) that runs on a PC, communicates with the NSP, and generates a spike-sorted model to guide the real-time spike inference. The NSP provides clocks and control signals to five 32-channel INTAN RHD2132 chips to manage the acquisition of 160 channels of raw neural data. In parallel, the NSP further filters, detects and extracts extracellular spike waveforms from the raw neural data recorded by tetrodes or silicon probes and assigns single-unit identity to each detected spike. A set of Python application programming interfaces (APIs) was developed in Spiketag to enable the communication between the NSP and the PC. These APIs allow the NSP to obtain a model from the PC, which holds parameters such as reference channels, spike detection thresholds, spike feature transformation matrix and vector quantized clusters generated by spike sorting a short recording session. Using the spike-sorted model, the NSP performs data acquisition and real-time spike inference simultaneously. Algorithmic modules were implemented in the FPGA and pipelined to compute during 40 ms acquisition intervals. At the output end of the FPGA NSP, the real-time assigned single-unit identity (spike-id) is packaged with the timestamp, the electrode group, and the spike features as a spike-id packet. Spike-id packets are asynchronously transmitted through a low-latency Peripheral Component Interconnect Express (PCIe) interface to the PC, producing the real-time spike trains. The real-time spike trains can be used for further processing, such as real-time decoding. Several types of ground-truth data, including intracellular/extracellular paired recordings, synthesized
tetrode extracellular waveforms with ground-truth spike timing and high-channel-count silicon probe recordings with ground-truth animal positions during navigation were used to validate the low-latency (1 ms) and high-accuracy (as high as state-of-the-art offline sorting and decoding algorithms) of the NSP’s real-time spike inference and the NSP-based
real-time population decoding performance
Architectural Support for High-Performance, Power-Efficient and Secure Multiprocessor Systems
High performance systems have been widely adopted in many fields and the demand for better performance is constantly increasing. And the need of powerful yet flexible systems is also increasing to meet varying application requirements from diverse domains. Also, power efficiency in high performance computing has been one of the major issues to be resolved. The power density of core components becomes significantly higher, and the fraction of power supply in total management cost is dominant. Providing dependability is also a main concern in large-scale systems since more hardware resources can be abused by attackers. Therefore, designing high-performance, power-efficient and secure systems is crucial to provide adequate performance as well as reliability to users.
Adhering to using traditional design methodologies for large-scale computing systems has a limit to meet the demand under restricted resource budgets. Interconnecting a large number of uniprocessor chips to build parallel processing systems is not an efficient solution in terms of performance and power. Chip multiprocessor (CMP) integrates multiple processing cores and caches on a chip and is thought of as a good alternative to previous design trends.
In this dissertation, we deal with various design issues of high performance multiprocessor systems based on CMP to achieve both performance and power efficiency while maintaining security. First, we propose a fast and secure off-chip interconnects through minimizing network overheads and providing an efficient security mechanism. Second, we propose architectural support for fast and efficient memory protection in CMP systems, making the best use of the characteristics in CMP environments and multi-threaded workloads. Third, we propose a new router design for network-on-chip (NoC) based on a new memory technique. We introduce hybrid input buffers that use both SRAM and STT-MRAM for better performance as well as power efficiency.
Simulation results show that the proposed schemes improve the performance of off-chip networks through reducing the message size by 54% on average. Also, the schemes diminish the overheads of bounds checking operations, thus enhancing the overall performance by 11% on average. Adopting hybrid buffers in NoC routers contributes to increasing the network throughput up to 21%
Investigation of delay jitter of heterogeneous traffic in broadband networks
Scope and Methodology of Study: A critical challenge for both wired and wireless networking vendors and carrier companies is to be able to accurately estimate the quality of service (QoS) that will be provided based on the network architecture, router/switch topology, and protocol applied. As a result, this thesis focuses on the theoretical analysis of QoS parameters in term of inter-arrival jitter in differentiated services networks by deploying analytic/mathematical modeling technique and queueing theory, where the analytic model is expressed in terms of a set of equations that can be solved to yield the desired delay jitter parameter. In wireless networks with homogeneous traffic, the effects on the delay jitter in reference to the priority control scheme of the ARQ traffic for the two cases of: 1) the ARQ traffic has a priority over the original transmission traffic; and 2) the ARQ traffic has no priority over the original transmission traffic are evaluated. In wired broadband networks with heterogeneous traffic, the jitter analysis is conducted and the algorithm to control its effect is also developed.Findings and Conclusions: First, the results show that high priority packets always maintain the minimum inter-arrival jitter, which will not be affected even in heavy load situation. Second, the Gaussian traffic modeling is applied using the MVA approach to conduct the queue length analysis, and then the jitter analysis in heterogeneous broadband networks is investigated. While for wireless networks with homogeneous traffic, binomial distribution is used to conduct the queue length analysis, which is sufficient and relatively easy compared to heterogeneous traffic. Third, develop a service discipline called the tagged stream adaptive distortion-reducing peak output-rate enforcing to control and avoid the delay jitter increases without bound in heterogeneous broadband networks. Finally, through the analysis provided, the differential services, was proved not only viable, but also effective to control delay jitter. The analytic models that serve as guidelines to assist network system designers in controlling the QoS requested by customer in term of delay jitter
Secure Diagnostics And Forensics With Network Provenance
In large-scale networks, many things can go wrong: routers can be misconfigured, programs can be buggy, and computers can be compromised by an attacker. As a result, there is a constant need to perform network diagnostics and forensics. In this dissertation, we leverage the concept of provenance to build better support for diagnostic and forensic tasks. At a high level, provenance tracks causality between network states and events, and produces a detailed explanation of any event of interest, which makes it a good starting point for investigating network problems.
However, in order to use provenance for network diagnostics and forensics, several challenges need to be addressed. First, existing provenance systems cannot provide security properties on high-speed network traffic, because the cryptographic operations would cause enormous overhead when the data rates are high. To address this challenge, we design secure packet provenance, a system that comes with a novel lightweight security protocol, to maintain secure provenance with low overhead. Second, in large-scale distributed systems, the provenance of a network event can be quite complex, so it is still challenging to identify the problem root cause from the complex provenance. To address this challenge, we design differential provenance, which can identify a symptom event’s root cause by reasoning about the differences between its provenance and the provenance of a similar “reference” event. Third, provenance can only explain why a current network state came into existence, but by itself, it does not reason about changes to the network state to fix a problem. To provide operators with more diagnostic support, we design causal networks – a generalization of network provenance – to reason about network repairs that can avoid undesirable side effects in the network. Causal networks can encode multiple diagnostic goals in the same data structure, and, therefore, generate repairs that satisfy multiple constraints simultaneously. We have applied these techniques to Software-Defined Networks, Hadoop MapReduce, as well as the Internet’s data plane. Our evaluation with real-world traffic traces and network topologies shows that our systems can run with reasonable overhead, and that they can accurately identify root causes of practical problems and generate repairs without causing collateral damage
Stay Connected, Leave no Trace: Enhancing Security and Privacy in WiFi via Obfuscating Radiometric Fingerprints
The intrinsic hardware imperfection of WiFi chipsets manifests itself in the
transmitted signal, leading to a unique radiometric fingerprint. This
fingerprint can be used as an additional means of authentication to enhance
security. In fact, recent works propose practical fingerprinting solutions that
can be readily implemented in commercial-off-the-shelf devices. In this paper,
we prove analytically and experimentally that these solutions are highly
vulnerable to impersonation attacks. We also demonstrate that such a unique
device-based signature can be abused to violate privacy by tracking the user
device, and, as of today, users do not have any means to prevent such privacy
attacks other than turning off the device.
We propose RF-Veil, a radiometric fingerprinting solution that not only is
robust against impersonation attacks but also protects user privacy by
obfuscating the radiometric fingerprint of the transmitter for non-legitimate
receivers. Specifically, we introduce a randomized pattern of phase errors to
the transmitted signal such that only the intended receiver can extract the
original fingerprint of the transmitter. In a series of experiments and
analyses, we expose the vulnerability of adopting naive randomization to
statistical attacks and introduce countermeasures. Finally, we show the
efficacy of RF-Veil experimentally in protecting user privacy and enhancing
security. More importantly, our proposed solution allows communicating with
other devices, which do not employ RF-Veil.Comment: ACM Sigmetrics 2021 / In Proc. ACM Meas. Anal. Comput. Syst., Vol. 4,
3, Article 44 (December 2020
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