12 research outputs found
Identity-Committable Signatures and Their Extension to Group-Oriented Ring Signatures
The identity of Deep Throat , a pseudonym of the information source in the Watergate scandal, remained mysterious for more than three decades. In 2005, an ex-FBI official claimed that he was the anonymous source. Nevertheless, some are still inconvinced. In this paper, we introduce a new notion of identity-committable signatures (ICS) to ensure the anonymity of Deep Throat inside a group. A member of an organization can sign a message on behalf of himself (regular signature) or the organization (identity-committed signature). In the latter case, the signer\u27s identity is hidden from anyone, and can be opened by himself only. We describe the requirements of ICS and give the formal definition of it.
Then we extend the notion of ICS to group-oriented ring signatures (GRS) which further allow the signer to hide his identity behind multiple groups. We believe a GRS scheme is more efficient and practical than a ring signature scheme for leaking secrets. Finally, we provide concrete constructions of ICS and GRS with information-theoretic anonymity, that is, the identity of the signer is fully-protected
Smart Grid Metering Networks: A Survey on Security, Privacy and Open Research Issues
Smart grid (SG) networks are newly upgraded networks of connected objects that greatly improve reliability, efficiency and sustainability of the traditional energy infrastructure. In this respect, the smart metering infrastructure (SMI) plays an important role in controlling, monitoring and managing multiple domains in the SG. Despite the salient features of SMI, security and privacy issues have been under debate because of the large number of heterogeneous devices that are anticipated to be coordinated through public communication networks. This survey paper shows a brief overview of real cyber attack incidents in traditional energy networks and those targeting the smart metering network. Specifically, we present a threat taxonomy considering: (i) threats in system-level security, (ii) threats and/or theft of services, and (iii) threats to privacy. Based on the presented threats, we derive a set of security and privacy requirements for SG metering networks. Furthermore, we discuss various schemes that have been proposed to address these threats, considering the pros and cons of each. Finally, we investigate the open research issues to shed new light on future research directions in smart grid metering networks
SoK: Sharding on Blockchain
Blockchain is a distributed and decentralized ledger for recording transactions. It is maintained and shared among the participating nodes by utilizing cryptographic primitives. A consensus protocol ensures that all nodes agree on a unique order in which records are appended. However, current blockchain solutions are facing scalability issues. Many methods, such as Off-chain and Directed Acyclic Graph (DAG) solutions, have been proposed to address the issue. However, they have inherent drawbacks, e.g., forming parasite chains. Performance, such as throughput and latency, is also important to a blockchain system. Sharding has emerged as a good candidate that can overcome both the scalability and performance problems in blockchain. To date, there is no systematic work that analyzes the sharding protocols. To bridge this gap, this paper provides a systematic and comprehensive review on blockchain sharding techniques. We first present a general design flow of sharding protocols and then discuss key design challenges. For each challenge, we analyze and compare the techniques in state-of-the-art solutions. Finally, we discuss several potential research directions in blockchain sharding
Transactional memory on heterogeneous architectures
Tesis Leida el 9 de Marzo de 2018.Si observamos las necesidades computacionales de hoy, y tratamos de predecir
las necesidades del mañana, podemos concluir que el procesamiento heterogéneo
estará presente en muchos dispositivos y aplicaciones.
El motivo es lógico: algoritmos diferentes y datos de naturaleza diferente encajan mejor
en unos dispositivos de cómputo que en otros. Pongamos como ejemplo una
tecnología de vanguardia como son los vehículos inteligentes. En este tipo de
aplicaciones la computación heterogénea no es una opción, sino un requisito.
En este tipo de vehículos se recolectan y analizan imágenes, tarea para la cual
los procesadores gráficos (GPUs) son muy eficientes.
Muchos de estos vehículos utilizan algoritmos sencillos,
pero con grandes requerimientos de tiempo real, que deben
implementarse directamente en hardware utilizando FPGAs.
Y, por supuesto, los procesadores multinúcleo tienen un
papel fundamental en estos sistemas, tanto organizando el trabajo de otros coprocesadores
como ejecutando tareas en las que ningún otro procesador
es más eficiente. No obstante, los procesadores tampoco siguen siendo dispositivos
homogéneos. Los diferentes núcleos de un procesador pueden
ofrecer diferentes características en términos de potencia y consumo
energético que se adapten a las necesidades de cómputo de la aplicación.
Programar este conjunto de dispositivos es una tarea compleja, especialmente
en su sincronización.
Habitualmente, esta sincronización se basa en operaciones atómicas, ejecución y
terminación de kernels, barreras y señales. Con estas primitivas de sincronización
básicas se pueden construir otras estructuras más complejas.
Sin embargo, la programación de estos
mecanismos es tediosa y propensa a fallos. La memoria transaccional
(TM por sus siglas en inglés) se ha propuesto como un mecanismo
avanzado a la vez que simple para garantizar la exclusión mutua
Techniques for Transparent Parallelization of Discrete Event Simulation Models
Simulation is a powerful technique to represent the evolution of real-world phenomena
or systems over time. It has been extensively used in different research
fields (from medicine to biology, to economy, and to disaster rescue) to study
the behaviour of complex systems during their evolution (symbiotic simulation)
or before their actual realization (what-if analysis).
A traditional way to achieve high performance simulations is the employment
of Parallel Discrete Event Simulation (PDES) techniques, which are based
on the partitioning of the simulation model into Logical Processes (LPs) that
can execute events in parallel on different CPUs and/or different CPU cores,
and rely on synchronization mechanisms to achieve causally consistent execution
of simulation events. As it is well recognized, the optimistic synchronization
approach, namely the Time Warp protocol, which is based on rollback for recovering
possible timestamp-order violations due to the absence of block-until-safe
policies for event processing, is likely to favour speedup in general application/
architectural contexts.
However, the optimistic PDES paradigm implicitly relies on a programming
model that shifts from traditional sequential-style programming, given
that there is no notion of global address space (fully accessible while processing
events at any LP). Furthermore, there is the underlying assumption that the
code associated with event handlers cannot execute unrecoverable operations
given their speculative processing nature. Nevertheless, even though no unrecoverable
action is ever executed by event handlers, a means to actually undo
the action if requested needs to be devised and implemented within the software
stack.
On the other hand, sequential-style programming is an easy paradigm for
the development of simulation code, given that it does not require the programmer
to reason about memory partitioning (and therefore message passing) and
speculative (concurrent) processing of the application.
In this thesis, we present methodological and technical innovations which
will show how it is possible, by developing innovative runtime mechanisms, to
allow a programmer to implement its simulation model in a fully sequential way,
and have the underlying simulation framework to execute it in parallel according
to speculative processing techniques. Some of the approaches we provide show
applicability in either shared- or distributed-memory systems, while others will
be specifically tailored to multi/many-core architectures.
We will clearly show, during the development of these supports, what is the
effect on performance of these solutions, which will nevertheless be negligible,
allowing a fruitful exploitation of the available computing power. In the end,
we will highlight which are the clear benefits on the programming model tha
A World-Class University-Industry Consortium for Wind Energy Research, Education, and Workforce Development: Final Technical Report
During the two-year project period, the consortium members have developed control algorithms for enhancing the reliability of wind turbine components. The consortium members have developed advanced operation and planning tools for accommodating the high penetration of variable wind energy. The consortium members have developed extensive education and research programs for educating the stakeholders on critical issues related to the wind energy research and development. In summary, The Consortium procured one utility-grade wind unit and two small wind units. Specifically, the Consortium procured a 1.5MW GE wind unit by working with the world leading wind energy developer, Invenergy, which is headquartered in Chicago, in September 2010. The Consortium also installed advanced instrumentation on the turbine and performed relevant turbine reliability studies. The site for the wind unit is InvenergyÃÂÃÂÃÂâÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂs Grand Ridge wind farmin Illinois. The Consortium, by working with Viryd Technologies, installed an 8kW Viryd wind unit (the Lab Unit) at an engineering lab at IIT in September 2010 and an 8kW Viryd wind unit (the Field Unit) at the Stuart Field on IITÃÂÃÂÃÂâÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂs main campus in July 2011, and performed relevant turbine reliability studies. The operation of the Field Unit is also monitored by the Phasor Measurement Unit (PMU) in the nearby Stuart Building. The Consortium commemorated the installations at the July 20, 2011 ribbon-cutting ceremony. The ConsortiumÃÂÃÂÃÂâÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂs researches on turbine reliability included (1) Predictive Analytics to Improve Wind Turbine Reliability; (2) Improve Wind Turbine Power Output and Reduce Dynamic Stress Loading Through Advanced Wind Sensing Technology; (3) Use High Magnetic Density Turbine Generator as Non-rare Earth Power Dense Alternative; (4) Survivable Operation of Three Phase AC Drives in Wind Generator Systems; (5) Localization of Wind Turbine Noise Sources Using a Compact Microphone Array; (6) Wind Turbine Acoustics - Numerical Studies; and (7) Performance of Wind Turbines in Rainy Conditions. The ConsortiumÃÂÃÂÃÂâÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂs researches on wind integration included (1) Analysis of 2030 Large-Scale Wind Energy Integration in the Eastern Interconnection; (2) Large-scale Analysis of 2018 Wind Energy Integration in the Eastern U.S. Interconnection; (3) Integration of Non-dispatchable Resources in Electricity Markets; (4) Integration of Wind Unit with Microgrid. The ConsortiumÃÂÃÂÃÂâÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂs education and outreach activities on wind energy included (1) Wind Energy Training Facility Development; (2) Wind Energy Course Development; (3) Wind Energy Outreach