152,446 research outputs found
Compensating mode conversion due to bend discontinuities through intentional trace asymmetry
In this letter, a comparative analysis is carried out between the mechanism of mode conversion in differential microstrip lines due to bend discontinuities on one side and trace asymmetry on the other side. With the help of equivalent modal circuits, a theoretical basis is provided for the idea to compensate the undesired common mode (CM), due to the presence of the bend, by intentionally designing asymmetric traces. As an application example, the proposed CM-reduction strategy is used in conjunction with another recently-presented wideband CM suppression filter for differential microstrip lines. It is shown that the proposed solution enhances the overall CM-reduction performance of the filter by some decibels, while preserving its transmission properties
Relaxing state-access constraints in stateful programmable data planes
Supporting the programming of stateful packet forwarding functions in
hardware has recently attracted the interest of the research community. When
designing such switching chips, the challenge is to guarantee the ability to
program functions that can read and modify data plane's state, while keeping
line rate performance and state consistency. Current state-of-the-art designs
are based on a very conservative all-or-nothing model: programmability is
limited only to those functions that are guaranteed to sustain line rate, with
any traffic workload. In effect, this limits the maximum time to execute state
update operations. In this paper, we explore possible options to relax these
constraints by using simulations on real traffic traces. We then propose a
model in which functions can be executed in a larger but bounded time, while
preventing data hazards with memory locking. We present results showing that
such flexibility can be supported with little or no throughput degradation.Comment: 6 page
Estimating the Potential Speedup of Computer Vision Applications on Embedded Multiprocessors
Computer vision applications constitute one of the key drivers for embedded
multicore architectures. Although the number of available cores is increasing
in new architectures, designing an application to maximize the utilization of
the platform is still a challenge. In this sense, parallel performance
prediction tools can aid developers in understanding the characteristics of an
application and finding the most adequate parallelization strategy. In this
work, we present a method for early parallel performance estimation on embedded
multiprocessors from sequential application traces. We describe its
implementation in Parana, a fast trace-driven simulator targeting OpenMP
applications on the STMicroelectronics' STxP70 Application-Specific
Multiprocessor (ASMP). Results for the FAST key point detector application show
an error margin of less than 10% compared to the reference cycle-approximate
simulator, with lower modeling effort and up to 20x faster execution time.Comment: Presented at DATE Friday Workshop on Heterogeneous Architectures and
Design Methods for Embedded Image Systems (HIS 2015) (arXiv:1502.07241
Asymmetric Leakage from Multiplier and Collision-Based Single-Shot Side-Channel Attack
The single-shot collision attack on RSA proposed by Hanley et al. is studied focusing on the difference between two operands of multiplier. It is shown that how leakage from integer multiplier and long-integer multiplication algorithm can be asymmetric between two operands. The asymmetric leakage is verified with experiments on FPGA and micro-controller platforms. Moreover, we show an experimental result in which success and failure of the attack is determined by the order of operands. Therefore, designing operand order can be a cost-effective countermeasure. Meanwhile we also show a case in which a particular countermeasure becomes ineffective when the asymmetric leakage is considered. In addition to the above main contribution, an extension of the attack by Hanley et al. using the signal-processing technique of Big Mac Attack is presented
Memory probes:Exploring retrospective user experience through traces of use on cherished objects
Our daily interactions with objects can not only leave traces of use on the objects but also leave memories in our minds. These human traces on objects are potential cues that can trigger our autobiographical memories and connect us to social networks. The first aim of this paper is to demonstrate what might be a suitable method of inquiry into the way materials can enrich dialogues about remembered experiences derived from human traces left on cherished possessions. The second aim is to investigate how the accumulation of human traces on objects influences people’s remembering and usage. The design of our research artifacts, Memory Probes, was situated in relation to three spectra of paired values: (1) the familiarity and strangeness of tool use, (2) the definiteness and ambiguity of data capture, and (3) the objective and subjective reality of interpretation. Our field study revealed a transactive nature between traces of interaction with possessions and memories in the owners’ minds. It also informed us of how gradual and curiosity-driven understanding could become a methodological nuance when we are empathetically engaged in a collaborative way of knowing with other participants. To conclude, several implications for designing products that can participate in our everyday reminiscing and meaning-making are proposed
Small-World File-Sharing Communities
Web caches, content distribution networks, peer-to-peer file sharing
networks, distributed file systems, and data grids all have in common that they
involve a community of users who generate requests for shared data. In each
case, overall system performance can be improved significantly if we can first
identify and then exploit interesting structure within a community's access
patterns. To this end, we propose a novel perspective on file sharing based on
the study of the relationships that form among users based on the files in
which they are interested.
We propose a new structure that captures common user interests in data--the
data-sharing graph-- and justify its utility with studies on three
data-distribution systems: a high-energy physics collaboration, the Web, and
the Kazaa peer-to-peer network. We find small-world patterns in the
data-sharing graphs of all three communities. We analyze these graphs and
propose some probable causes for these emergent small-world patterns. The
significance of small-world patterns is twofold: it provides a rigorous support
to intuition and, perhaps most importantly, it suggests ways to design
mechanisms that exploit these naturally emerging patterns
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