2,955 research outputs found
On the tradeoffs between network state knowledge and secrecy
In this paper, the impact of network-state knowledge on the feasibility of secrecy is studied in the context of non-colluding active eavesdropping. The main contribution is the investigation of several scenarios in which increasing the available knowledge at each of the network components leads to some paradoxical observations in terms of the average secrecy capacity and average information leakage. These observations are in the context of a broadcast channel similar to the time-division downlink of a single-cell cellular system. Here, providing more knowledge to the eavesdroppers makes them more conservative in their attacks, and thus, less harmful in terms of average information leakage. Similarly, providing more knowledge to the transmitter makes it more careful and less willing to transmit, which reduces the expected secrecy capacity. These findings are illustrated with a numerical analysis that shows the impact of most of the network parameters in the feasibility of secrecy. © 2013 NICT
Congress' Wicked Problem: Seeking Knowledge Inside the Information Tsunami
The lack of shared expert knowledge capacity in the U.S. Congress has created a critical weakness in our democratic process. Along with bipartisan cooperation, many contemporary and urgent questions before our legislators require nuance, genuine deliberation and expert judgment. Congress, however, is missing adequate means for this purpose and depends on outdated and in some cases antiquated systems of information referral, sorting, communicating, and convening. Congress is held in record low esteem by the public today. Its failings have been widely analyzed and a multitude of root causes have been identified. This paper does not put forward a simple recipe to fix these ailments, but argues that the absence of basic knowledge management in our legislature is a critical weakness. Congress struggles to make policy on complex issues while it equally lacks the wherewithal to effectively compete on substance in today's 24 hour news cycle.This paper points out that Congress is not so much venal and corrupt as it is incapacitated and obsolete. And, in its present state, it cannot serve the needs of American democracy in the 21st Century.The audience for this paper is those who are working in the open government, civic technology and transparency movements as well as other foundations, think tanks and academic entities. It is also for individuals inside and outside of government who desire background about Congress' current institutional dilemmas, including lack of expertise
Physical Layer Service Integration in 5G: Potentials and Challenges
High transmission rate and secure communication have been identified as the
key targets that need to be effectively addressed by fifth generation (5G)
wireless systems. In this context, the concept of physical-layer security
becomes attractive, as it can establish perfect security using only the
characteristics of wireless medium. Nonetheless, to further increase the
spectral efficiency, an emerging concept, termed physical-layer service
integration (PHY-SI), has been recognized as an effective means. Its basic idea
is to combine multiple coexisting services, i.e., multicast/broadcast service
and confidential service, into one integral service for one-time transmission
at the transmitter side. This article first provides a tutorial on typical
PHY-SI models. Furthermore, we propose some state-of-the-art solutions to
improve the overall performance of PHY-SI in certain important communication
scenarios. In particular, we highlight the extension of several concepts
borrowed from conventional single-service communications, such as artificial
noise (AN), eigenmode transmission etc., to the scenario of PHY-SI. These
techniques are shown to be effective in the design of reliable and robust
PHY-SI schemes. Finally, several potential research directions are identified
for future work.Comment: 12 pages, 7 figure
Recent Advances in Joint Wireless Energy and Information Transfer
In this paper, we provide an overview of the recent advances in
microwave-enabled wireless energy transfer (WET) technologies and their
applications in wireless communications. Specifically, we divide our
discussions into three parts. First, we introduce the state-of-the-art WET
technologies and the signal processing techniques to maximize the energy
transfer efficiency. Then, we discuss an interesting paradigm named
simultaneous wireless information and power transfer (SWIPT), where energy and
information are jointly transmitted using the same radio waveform. At last, we
review the recent progress in wireless powered communication networks (WPCN),
where wireless devices communicate using the power harvested by means of WET.
Extensions and future directions are also discussed in each of these areas.Comment: Conference submission accepted by ITW 201
Sparse Signal Processing Concepts for Efficient 5G System Design
As it becomes increasingly apparent that 4G will not be able to meet the
emerging demands of future mobile communication systems, the question what
could make up a 5G system, what are the crucial challenges and what are the key
drivers is part of intensive, ongoing discussions. Partly due to the advent of
compressive sensing, methods that can optimally exploit sparsity in signals
have received tremendous attention in recent years. In this paper we will
describe a variety of scenarios in which signal sparsity arises naturally in 5G
wireless systems. Signal sparsity and the associated rich collection of tools
and algorithms will thus be a viable source for innovation in 5G wireless
system design. We will discribe applications of this sparse signal processing
paradigm in MIMO random access, cloud radio access networks, compressive
channel-source network coding, and embedded security. We will also emphasize
important open problem that may arise in 5G system design, for which sparsity
will potentially play a key role in their solution.Comment: 18 pages, 5 figures, accepted for publication in IEEE Acces
Intra-organizational integration and innovation: organizational structure, environmental contingency and R&D performance
It is widely thought that intra-firm integration has a positive effect on organizational performance, especially in environments characterized by complex and uncertain information. However, counter arguments suggest that integration may limit flexibility and thereby reduce performance in the face of uncertainty. Research and development activities of a firm are especially likely to face complex and uncertain information environments. Following prior work in contingency theory, this paper analyzes the effects of intra-organizational integration on manufacturing firms’ innovative performance. Based on a survey of R&D units in US manufacturing firms and patent data from the NBER patent database, we examine the relation between mechanisms for linking R&D to other units of the firm and the relative innovativeness of the firm. Furthermore, we argue that the impact of integration may vary by the importance of secrecy in protecting firms’ innovation advantages. We find that intra-firm integration is associated with higher self-reported innovativeness and more patents. We also find some evidence that this effect is moderated by the appropriability regime the firm faces, with the benefits of cross-functional integration being weaker in industries where secrecy is especially important. These results both support and develop the contingency model of organizational performance.Innovation; Organizations; Contingency theory;
Efficient Wireless Security Through Jamming, Coding and Routing
There is a rich recent literature on how to assist secure communication
between a single transmitter and receiver at the physical layer of wireless
networks through techniques such as cooperative jamming. In this paper, we
consider how these single-hop physical layer security techniques can be
extended to multi-hop wireless networks and show how to augment physical layer
security techniques with higher layer network mechanisms such as coding and
routing. Specifically, we consider the secure minimum energy routing problem,
in which the objective is to compute a minimum energy path between two network
nodes subject to constraints on the end-to-end communication secrecy and
goodput over the path. This problem is formulated as a constrained optimization
of transmission power and link selection, which is proved to be NP-hard.
Nevertheless, we show that efficient algorithms exist to compute both exact and
approximate solutions for the problem. In particular, we develop an exact
solution of pseudo-polynomial complexity, as well as an epsilon-optimal
approximation of polynomial complexity. Simulation results are also provided to
show the utility of our algorithms and quantify their energy savings compared
to a combination of (standard) security-agnostic minimum energy routing and
physical layer security. In the simulated scenarios, we observe that, by
jointly optimizing link selection at the network layer and cooperative jamming
at the physical layer, our algorithms reduce the network energy consumption by
half
Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey
This paper provides a comprehensive review of the domain of physical layer
security in multiuser wireless networks. The essential premise of
physical-layer security is to enable the exchange of confidential messages over
a wireless medium in the presence of unauthorized eavesdroppers without relying
on higher-layer encryption. This can be achieved primarily in two ways: without
the need for a secret key by intelligently designing transmit coding
strategies, or by exploiting the wireless communication medium to develop
secret keys over public channels. The survey begins with an overview of the
foundations dating back to the pioneering work of Shannon and Wyner on
information-theoretic security. We then describe the evolution of secure
transmission strategies from point-to-point channels to multiple-antenna
systems, followed by generalizations to multiuser broadcast, multiple-access,
interference, and relay networks. Secret-key generation and establishment
protocols based on physical layer mechanisms are subsequently covered.
Approaches for secrecy based on channel coding design are then examined, along
with a description of inter-disciplinary approaches based on game theory and
stochastic geometry. The associated problem of physical-layer message
authentication is also introduced briefly. The survey concludes with
observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with
arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials,
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