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—We present the Crossfire attack – a powerful attack that degrades and often cuts off network connections to a variety of selected server targets (e.g., servers of an enterprise, a city, a state, or a small country) by flooding only a few network links. In Crossfire, a small set of bots directs low-intensity flows to a large number of publicly accessible(More)
—In this letter, we propose a pre-whitening scheme for a spectrum-sharing environment where multiple antennas are used for both primary and secondary users. The proposed pre-whitening scheme is different from the conventional post-whitening scheme for mitigating multiple-input and multiple-output (MIMO) interference because a primary receiver does not(More)
Large-scale botnet attacks against Internet links using low-rate flows cannot be effectively countered by any of the traditional rate-limiting and flow-filtering mechanisms deployed in individual routers. In this paper, we present a collaborative defense mechanism, called CoDef, which enables routers to distinguish low-rate attack flows from legitimate(More)
BACKGROUND Premature shortening of leukocyte telomere length has been proposed as a novel mechanism by which depression may confer increased risk of adverse cardiovascular events. Prior studies demonstrating associations of depression and depressive symptoms with shorter leukocyte telomere length were small, included selected psychiatric outpatients, were(More)
— In this paper, we proposed an adaptive sub-band exclusion (ASE) scheme as a means of intercell interference coordination (ICIC) technique to improve the performance of wireless cellular systems in a decentralized manner. It excludes some portion of orthogonal frequency division multiplexing (OFDM) sub-bands inducing the most significant interference to(More)
In this paper, we investigate the effect of cooperative and selection relaying schemes on multiuser diversity in downlink cellular systems with fixed relay stations (RSs). Each mobile station (MS) is either directly connected to a base station (BS) and/or connected to a relay station. We first derive closed-form solutions or upper-bound of the ergodic and(More)
—We have recently witnessed the real life demonstration of link-flooding attacks—DDoS attacks that target the core of the Internet that can cause significant damage while remaining undetected. Because these attacks use traffic patterns that are indistinguishable from legitimate TCP-like flows, they can be persistent and cause long-term traffic disruption.(More)
How pervasive is the vulnerability to link-flooding attacks that degrade connectivity of thousands of Internet hosts? Are some geographic regions more vulnerable than others? Do practical countermeasures exist? To answer these questions, we introduce the notion of the routing bottlenecks and show that it is a fundamental property of Internet design; i.e.,(More)
In today's cellular networks, user equipment (UE) have suffered from low spectral efficiency at cell-edge region due to high interference from adjacent base stations (BSs), which share the same spectral radio resources. In the recently proposed cooperative cellular networks, geographically separated multiple BSs cooperate on transmission in order to improve(More)