In a wormhole attack, colluding nodes create connecting the purported neighbors using a covert the illusion that two remote regions of a MANET are communication mechanism. The wormhole undermines directly connected through nodes that appear to be shortest path routing calculations, allowing the attacking neighbors, but are actually distant from each other. This nodes to attract traffic from other parts of the network so it is undermines shortest-path routing calculations, allowing routed through them. The wormhole thus creates two artificial the attacking nodes to attract traffic, which can then be traffic choke points that are under the control of the attacker manipulated. Prior research has concentrated on out-of-and can be utilized at an opportune future time to degrade or band wormholes, which covertly connect the purported analyze the traffic stream.neighbors via a separate wireline network or RF channel.Prior research on wormholes in MANETs has concentratedWe present a detailed description of in-band wormholes in primarily on out-of-band wormholes, which covertly connect OLSR networks. These connect the purported neighbors purported neighbors via a separate communication via covert, multi-hop tunnels. In-band wormholes are an mechanism, such as a wireline network or additional RF important threat because they do not require specialized channel that is not generally available throughout the network hardware and can be launched by any node in the [HU03] [HONG05]. This paper describes in detail, in-band MANET. Moreover, unlike out-of-band wormholes, in-wormholes, which covertly connect the purported neighbors band wormholes consume network capacity, inherently via multi-hop tunnels through the primary link layer. In-band degrading service. We explain the conditions under which wormholes are important for several reasons. First, because an in-band wormhole will collapse and how it can be made they do not require additional specialized hardware, they can collapse resilient. We identify the self-contained and be launched from any node in the network; as a result, they extended forms of in-band wormholes and present may be more likely to be used by real adversaries. Second, wormhole gravitational analysis, a technique for comparing unlike out-of-band wormholes, which actually add channel the effect of wormholes on the network. Finally, we identify potential countermeasures for preventing and capacit toth network, in-an wormholes tinualy consume network ca acity i.e. waste bandwidth) thereby detecting in-band wormholes based on packet loss rates, .y ..y packet delays, and topological characteristics, and we inhermen asurs service degrandaton. Thrd athough describe the results of initial laboratory experiments to cout-of-band wormhols sem toodepend assess theireffectiveness, on out-of-band mechanisms such as geographic position assess their effectiveness. information or highly synchronized clocks, countermeasures Index Terms-Computer network security, routing, for in-band wormholes may not. mobile communications, re...
Transarterial chemoembolization (TACE) is a proven catheter-based locoregional therapy for treatment of hepatocellular carcinoma (HCC). Drug-eluting bead TACE involves delivering micrometer-sized particles preloaded with doxorubicin directly to the tumor via its arterial blood supply and results in vascular embolization with intra-tumoral drug release. Effective therapy requires mapping of the tumor arterial supply, which in some cases cannot be accomplished with conventional angiographic techniques alone. Contrast-enhanced ultrasound (CEUS) is an imaging technique which utilizes microbubble contrast agents to demonstrate blood flow and tissue perfusion, enabling tumor visualization in real time. CEUS with intravenous contrast administration is well established for evaluation of HCC. Intra-arterial (IA) CEUS, on the other hand, is an emerging technique that allows more selective evaluation of the arterial supply to the tumor. The three cases in this report illustrate the utility of intra-procedural IA CEUS during TACE. Specifically, IA CEUS aided TACE in cases where the HCC showed poor arterial enhancement, an extrahepatic arterial supply, and a portal venous supply, respectively.
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To support research in wireless mobile networks and mobile ad-hoc network security, the u.s. Army Research Laboratory (ARL) has developed a HWireless Emulation Laboratory" (WEL). A key component of the WEL is a Mobile Ad-hoc Network (MANET) emulation testbed on which algorithms and applications can be subjected to emulated wireless network conditions. The testbed is based on the MANE (Mobile Ad-hoc Network Emulator) software originally developed by the Naval Research Laboratory (NRL). It has since been improved through the incorporation of advanced modeling methods and computing technologies. Important additional features include (1) the integration of the terrain integrated rough earth model (TIREM) propagation model, (2) the use of virtual machine technologies to scale the size of the network, and (3) the inclusion of custom-designed mobility patterns to create a specific dynamic topology ofa MANET under test. Currently the WEL testbed can emulate a 101-node MANET and, through the use of virtualization technologies, will scale well beyond that number. This paper discusses the current capabilities ofARL's WEL for conducting empirical evaluation and demonstration of MANET technologies and concludes with planned future enhancements. I.
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