STONE: a stream-based DDoS defense framework

An effective Distributed Denial of Service (DDoS) defense mechanism must guarantee legitimate users access to an Internet service masking the effects of possible attacks. That is, it must be able to detect threats and discard malicious packets in a online fashion. Given that emerging data streaming technology can enable such mitigation in an effective manner, in this paper we present STONE, a stream-based DDoS defense framework, which integrates anomaly-based DDoS detection and mitigation with scalable data streaming technology. With STONE, the traffic of potential targets is analyzed via continuous data streaming queries maintaining information used for both attack detection and mitigation. STONE provides minimal degradation of legitimate users traffic during DDoS attacks and it also faces effectively flash crowds. Our preliminary evaluation based on an implemented prototype and conducted with real legitimate and malicious traffic traces shows that STONE is able to provide fast detection and precise mitigation of DDoS attacks leveraging scalable data streaming technology.

Low latency LDGM code for multimedia-packet stream in bursty packet loss networks

In this paper we present a FEC scheme based on simple LDGM codes to protect packetized multimedia streams. We demonstrate that simple LDGM codes working with a limited number of packets (small values of k) obtain recovery capabilities, against bursty packet losses, that are similar to those of other more complex FEC-based schemes designed for this type of channels.

Geomorphological analysis and evolution of an altered floodplain drainage system. The case of the Partido Stream (Spain)

The Partido Stream is a small torrential course that flows into the marsh of the Doñana National Park, an area that was declared a World Heritage Site in 1994. Before 1981, floods occurred, and the stream overflowed onto a floodplain. As an old alluvial fan, the floodplain has its singular orography and functionality. Fromthe floodplain, several drainage channels, locally called caño, discharged into themarsh. The Partido Streamhad themorphology of a caño and covered approximately 8 km from the old fan to the marsh. The stream was straightened and channelised in 1981 to cultivate the old fan. This resulted in floods that were concentrated between the banks in the following years, which caused the depth of water and the shear stress to increase, thus, scouring the river bed and river banks. In this case, the eroded materials were carried towards the marsh where a new alluvial fan evolved. Control measures on the old fan were implemented in 2006 to stop the development of the new alluvial fan downstream over the marsh. Thus, the stream would partially recover its original behaviour that it had before channelisation, moving forwards in a new, balanced state. The present study describes the geomorphological evolution that channelisation has caused since 1981 and the later slow process of recovery of the original hydraulic-sedimentation regime since 2006. Additionally, it deepens the understanding of the original hydraulic behaviour of the stream, combining field data and 2D simulations.

Alteración del comportamiento hidráulico natural de la vertiente noreste de la marisma de El Rocío por efectos antrópicos

El geo-dinamismo torrencial es resultado de la incidencia de precipitaciones torrenciales en la cuenca hidrográfica, y se manifiesta por una intensificación del ciclo del agua (con la presencia de mayores volúmenes de escorrentía y la consiguiente aparición de repentinos y elevados caudales de avenida) e intensificación del ciclo de los sedimentos (mayor erosión del suelo, incremento del transporte de sedimentos en los cauces de drenaje y la formación de grades depósitos de sedimentos en el área dominada de la cuenca). Estos procesos naturales se pueden agravar si se realizan en la cuenca actuaciones que alteren sustancialmente su morfología; es el caso del arroyo del Partido, tributario a la marisma de El Rocío en el Parque Nacional de Doñana, cuyo encauzamiento del tramo final sobre su antiguo cono de sedimentación fue el causante de la formación de un nuevo cono de sedimentación sobre la marisma. Pero las intervenciones antrópicas también pueden dirigir el sistema hacia la estabilidad sedimentaria y el tramo final del arroyo del Partido ha experimentado asimismo actuaciones de carácter restaurador. El antiguo cono de sedimentación del arroyo del Partido es un lugar complejo en el que drenan también otros tres cursos que intercambian sus flujos con dicho arroyo durante las avenidas. Esta Memoria analiza cuatro situaciones del paraje objeto de estudio: la primera responde al estado original del lugar en cuestión (situación A); la segunda a la creada tras el encauzamiento del arroyo del Partido en 1981 (situación B); la tercera a la formada pasado un tiempo desde el encauzamiento, cuando el geo-dinamismo del lugar hizo sus efectos sobre el paraje en cuestión (situación C); y la cuarta la generada tras la restauración en el verano de 2006 del régimen hidráulico-sedimentario del arroyo del Partido con la Actuación núm. 3 del Proyecto Doñana 2005. Se han investigado los efectos que la alteración de la morfología del sistema de drenaje del antiguo cono de sedimentación del arroyo del Partido causa en los parámetros hidráulicos que desencadenan el geo-dinamismo torrencial. Para ello se han reproducido las condiciones morfológicas de las cuatro situaciones más representativas ya comentadas que ha experimentado el paraje en los últimos 30 años y que han condicionado el comportamiento de las avenidas torrenciales ocurridas en dicho periodo. En este contexto se ha elaborado un modelo hidrológico con el programa HECHMS a partir de la información disponible y un modelo hidrodinámico en 2D con el programa IBER; con este último se han comparado ocho escenarios característicos derivados de la incidencia de dos avenidas representativas de los eventos torrenciales de la zona sobre las morfologías contempladas. También se ha estudiado la tensión de arrastre de las avenidas dada su incidencia en el terreno sobre el que transitan, analizando de manera separada los efectos en los cuatro cauces de drenaje del antiguo cono de sedimentación y del resto de la superficie del mismo. La investigación realizada ha permitido describir minuciosamente el comportamiento de los drenajes locales del antiguo y complejo cono de sedimentación que bordea el noroeste de la marisma del Parque Nacional de Doñana, desde la marisma de El Rocío hasta la marisma gallega, lo que redundará en beneficio de la gestión del Parque Nacional de Doñana y de su entorno, y especialmente en la seguridad del perímetro oriental de la aldea de El Rocío. ABSTRACT The torrential geo-dynamism results from the effect of torrential precipitations on the hydrological watershed, and it shows ups with the intensification of the water cycle (with presence of higher volumes of run-off and the consequent appearance of sudden and high food flows) and intensification of the sediment cycle (higher soil erosion, increase of sediment transport in the drainage courses and the formation of big sediment deposits in the area downstream the watershed). These natural processes can worsen if actions that change the morphology of the watershed are carried out. It is the case of the Partido stream, tributary of the marsh of El Rocío in the Doñana National Park, whose channelization of the final stretch over its old alluvial fan was the cause of the formation of a new alluvial fan over the marsh. But human actions can also go toward the sediment stabilization, and the final stretch of the Partido stream has experienced restoration actions as well. The old alluvial fan of the Partido stream is a complex terrain where also other three courses exchange their flows during floods. This document analyses four situations of the area studied: the first corresponds to the original state of the place (situation A); the second is the state created after the channel of the Partido stream was built in 1981 (situation B); the third is the state formed after some time passed and the geo-dynamism caused effect in the channelization (situation C); and the forth situation is the one created after the restoration in summer of 2006 of the hydraulic-sedimentary regime of the Partido stream with de Action number 3 of the Doñana 2005 Project. It has been researched the effects that the alteration of the morphology of the drainage system of the old alluvial fan of the Partido stream causes to the hydraulic parameters that trigger the torrential geo-dynamism. For that, the morphologic conditions of the four more representative situations were reproduced. Those situations experienced in the area in the last 30 years have conditioned the behaviour of torrential floods in that period. In this context, a hydrologic model with HEC-HMS and a 2D hydro-dynamic model with IBER have been set up. With IBER, eight scenes have been compared resulting from the impact of two representative floods from torrential events in the region against the morphologies considered. Also, the shear stress of the floods on the terrain has been studied, analysing separately the effect in the four drainage courses of the old alluvial fan and in the rest of its surfaces. The research carried out has allowed describing in minute detail the behavior of the local drainages of the old and complex alluvial fan that border the northwest part of the marsh of Doñana National Park, from the marsh of El Rocío to the gallega marsh. This will result in benefit for the management of Doñana National Park and its surroundings, and especially for the safety of the eastern limit of El Rocío village.

Dynamic media stream mobility with TURN

Multi party videoconference systems use MCU (Multipoint Control Unit) devices to forward media streams. In this paper we describe a mechanism that allows the mobility of such streams between MCU devices. This mobility is especially useful when redistribution of streams is needed due to scalability requirements. These requirements are mandatory in Cloud scenarios to adapt the number of MCUs and their capabilities to variations in the user demand. Our mechanism is based on TURN (Traversal Using Relay around NAT) standard and adapts MICE (Mobility with ICE) specification to the requirements of this kind of scenarios. We conclude that this mechanism achieves the stream mobility in a transparent way for client nodes and without interruptions for the users.

RDSZ: an approach for lossless RDF stream compression

In many applications (like social or sensor networks) the in- formation generated can be represented as a continuous stream of RDF items, where each item describes an application event (social network post, sensor measurement, etc). In this paper we focus on compressing RDF streams. In particular, we propose an approach for lossless RDF stream compression, named RDSZ (RDF Differential Stream compressor based on Zlib). This approach takes advantage of the structural similarities among items in a stream by combining a differential item encoding mechanism with the general purpose stream compressor Zlib. Empirical evaluation using several RDF stream datasets shows that this combi- nation produces gains in compression ratios with respect to using Zlib alone.

NEMAWASHI: Attaining Value Stream alignment within Complex Organizational Networks

In the process of value creation, organizations perform an intense intra-organizational dialog through which internal VS alignment is achieved towards certain strategic objectives. Within the context of complex organizational networks, were goal conflicts are preprogrammed through incentive structures, VS alignment as legitimation of action towards strategic goals has special interest. On the one hand it facilitates the access to necessary resources for goal achievement and on the other it increases the sustainability and supports commonly agreed upon decisions leading to success. This paper provides a winnerless process (WLP) differential equations model for quantifying intra-organizational value stream (VS) alignment dynamics that can help design sustainable lean management solutions. This paper presents ongoing research results that show how the model was implemented in one industrial facility.

Spatial aggregation of time-variant stream water ages in urbanizing catchments

Date of Acceptance: 25/03/2015

Stream biodiversity: The ghost of land use past

The influence of past land use on the present-day diversity of stream invertebrates and fish was investigated by comparing watersheds with different land-use history. Whole watershed land use in the 1950s was the best predictor of present-day diversity, whereas riparian land use and watershed land use in the 1990s were comparatively poor indicators. Our findings indicate that past land-use activity, particularly agriculture, may result in long-term modifications to and reductions in aquatic diversity, regardless of reforestation of riparian zones. Preservation of habitat fragments may not be sufficient to maintain natural diversity in streams, and maintenance of such biodiversity may require conservation of much or all of the watershed.

Improving Colorado Mountain Highway Culvert Stream Crossings for Trout Passage

Highways can be effective barriers to animal migration. Where highways cross over streams, a passageway, typically a culvert, not designed for fish access can cut off an organism from miles of habitat. Traditional methods of culvert design, to convey floodwaters, reduced access to aquatic and riparian range. The Colorado Department of Transportation likely has numerous culverts that restrict aquatic passage. This paper provides guidance to CDOT for assessment of stream geomorphic conditions affecting culvert performance for fish passage, understanding aquatic organism habitat requirements, and incorporating ecological parameters into culvert designs that benefit fish and other organisms. A case study illustrates culvert problems in a difficult geomorphic setting including a fish passage assessment to evaluate stream stability for long-term culvert reliability.

Report on the Hydroida : collected during the exploration of the Gulf Stream by L. F. de Pourtalès, assistant United States Coast Survey / by Geo. J. Allman, M.D., LL.D., ...

v.5:no.2 (1877)

Analysis of Hyporheic Flow Induced by a Bar in a Gravel Stream: an Experimental Study

Thesis (Master, Civil Engineering) -- Queen's University, 2016-06-01 00:03:02.939

On Ukrainian Gas Transit and South Stream. There may be more than meets the eye. CEPS Commentaries, 21 March 2014

The EU relies to a considerable degree on imports to meet its demand for natural gas. Whereas Norwegian export pipelines are directly connected to the EU gas system, a major share of Russian gas flows through the Ukrainian territory before reaching consumers located other consumers located down in the supply chain (e.g. Slovakia, Hungary or Italy). But is the Ukrainian gas transit route still a risk? Will the construction of the South Stream pipeline further reduce the importance of Ukraine as a transit country? Or is there more at stake here than meets the eye?