Backscatter Datasets Research Articles

Secured Icmp Based Ip Traceback Scheme To Trace The Spoofed Ip Locations

The Internet Protocol (IP) is the basic protocol for sending data over the Internet and many other computer networks. IP spoofing is the creation of Internet Protocol (IP) packets with a forged source IP address, with the purpose of thrashing the identity of the sender or an attacker can make it appear that the packet was sent by a different machine. The objective of this paper is to devise the passive IP trace back (PIT) scheme using Internet Control Message Protocol(ICMP) to avoid the operational obstacles of IP trace back schemes. PIT investigates ICMP error messages (path backscatter) triggered by spoofing traffic, and tracks the spoofers based on public available information (eg.topology). This scheme(PIT) discover the spoofers without any operational requirement and exhibits the causes, collection, and the statistical results on path backscatter, demonstrates the processes and effectiveness of PIT, and shows the captured locations of spoofers throughout applying PIT on the path backscatter data set. These results are capable of expose the spoofed IP locations.

Chi-Square Statistical based Technique for Intrusion Detection

Tools required for the security purposes are firewall, passwords, IDS, IPS for the detection of anomaly and prevent it from sending out the harmful traffic to the network. So, it is very necessary to examine the behavior of traffic that coming to the network and recognize the anomalous behavior. In this paper, statistical based chi-square method is used to detect the anomalous behavior and predict the intrusions by calculating the observed and expected frequencies. Setting of interval is difficult for the detection of anomaly but in our case we set interval according to the less variation in traffic. Traffic contains from the backscatter dataset. Chi-square method is good to detect the anomalous behaviors because it gives the Poisson’s distribution for the whole traffic on network. Large difference shows anomaly occurs.

Passive IP Traceback: Disclosing the Locations of IP Spoofers From Path Backscatter

It is long known attackers may use forged source IP address to conceal their real locations. To capture the spoofers, a number of IP traceback mechanisms have been proposed. However, due to the challenges of deployment, there has been not a widely adopted IP traceback solution, at least at the Internet level. As a result, the mist on the locations of spoofers has never been dissipated till now. This paper proposes passive IP traceback (PIT) that bypasses the deployment difficulties of IP traceback techniques. PIT investigates Internet Control Message Protocol error messages (named path backscatter) triggered by spoofing traffic, and tracks the spoofers based on public available information (e.g., topology). In this way, PIT can find the spoofers without any deployment requirement. This paper illustrates the causes, collection, and the statistical results on path backscatter, demonstrates the processes and effectiveness of PIT, and shows the captured locations of spoofers through applying PIT on the path backscatter data set. These results can help further reveal IP spoofing, which has been studied for long but never well understood. Though PIT cannot work in all the spoofing attacks, it may be the most useful mechanism to trace spoofers before an Internet-level traceback system has been deployed in real.

Improving seabed classification from Multi-Beam Echo Sounder (MBES) backscatter data with visual data mining

Multi-Beam Echo Sounders are often used for classification of seabed type, as there exists a strong link between sonar backscatter and sediment characteristics of the seabed. Most of the methods for seabed classification from MBES backscatter create a highly-dimensional data set of statistical features and then use a combination of Principal Component Analysis and k-means clustering to derive classes. This procedure can be time consuming for contemporary large MBES data sets with millions of records. This paper examines the complexity of one of most commonly used classification approaches and suggests an alternative where feature data set is optimised in terms of dimensionality using computational and visual data mining. Both the original and the optimised method are tested on an MBES backscatter data set and validated against ground truth. The study found that the optimised method improves accuracy of classification and reduced complexity of processing. This is an encouraging result, which shows that bringing together methods from acoustic classification, visual data mining, spatial analysis and remote sensing can support the unprecedented increases in data volumes collected by contemporary acoustic sensors.

Geomorphology of submerged reefs on the shelf edge of the Great Barrier Reef: The influence of oscillating Pleistocene sea-levels

The submerged reefs on continental margins and surrounding oceanic islands are important archives of past climates, eustatic sea-level oscillations and oceanographic processes. Australia's north eastern submerged shelf edge reefs have previously been explored, but all studies have been limited by either low-resolution single beam profiles or by their limited spatial extent. The aim of this study is to improve the understanding of the origin and development of submerged shelf edge reefs, terraces and related features on the Great Barrier Reef (GBR), and the influence of Pleistocene sea-level oscillations on their distribution and geomorphology. We investigated the first large-scale (1400 km 2) 3D bathymetry and acoustic backscatter dataset of four widely-spaced sites located across ca. 650 km along the shelf edge at Ribbon Reefs 1–5, Noggin Pass, Viper Reef and Hydrographers Passage. We provide a comprehensive description and systematic classification of the shelf edge features, and constrain their spatial distribution and geomorphologic variability using a wide range of quantitative morphometrics. Fifteen features are defined, four of which are the focus of this study, including terraces, pinnacles, ridges and channels. Using modern reefs within the GBR for comparison, we interpret these as fringing reefs, patch and barrier reefs and tidal channels respectively. The influence of gross shelf geomorphology and oceanographic factors driving the observed variability within and between sites is discussed in conjunction with Mid-Late Pleistocene sea-level oscillations. We observed two distinct types of reef growth characterised by the degree of development, which we interpret as analogous to juvenile and mature modern reefs of the GBR. Juvenile reefs are very common and occur within each site at depths of less than 50 m to greater than 100 m. They are defined as discontinuous peaked barrier reefs, peaked patch reefs and fringing reefs. Mature reefs are less common and develop exclusively at a depth range of ca. 50–70 m. These reefs are defined as flat-topped continuous barrier and double barrier reefs. Through a comparison with published Mid-Late Pleistocene sea-level oscillations, we note that the depth range of mature reefs is consistent with the depth of repeated low-amplitude (< 20 m) eustatic sea-level oscillations, and independent of the relative time spent at sea-level. We conclude that repeated low-amplitude sea-level rises provide the much-needed accommodation space for vertical accretion that is not provided during stillstands, without inducing reef drowning, which can be caused by high-amplitude sea-level rise. Low-amplitude sea-level falls are also less detrimental than high-amplitude falls, in terms of habitat compression. Together, the effects of enhanced reef accretion and limited habitat compression at depths of 50–70 m have lead to a concentrated net gain in vertical relief that is not observed elsewhere on the shelf edge.

Quantitative experimental comparison of single-beam, sidescan, and multibeam benthic habitat maps

Abstract Schimel, A. C. G., Healy, T. R., Johnson, D., and Immenga, D. 2010. Quantitative experimental comparison of single-beam, sidescan, and multibeam benthic habitat maps. – ICES Journal of Marine Science, 67: 1766–1779. Map comparison is a relatively uncommon practice in acoustic seabed classification to date, contrary to the field of land remote sensing, where it has been developed extensively over recent decades. The aim here is to illustrate the benefits of map comparison in the underwater realm with a case study of three maps independently describing the seabed habitats of the Te Matuku Marine Reserve (Hauraki Gulf, New Zealand). The maps are obtained from a QTC View classification of a single-beam echosounder (SBES) dataset, manual segmentation of a sidescan sonar (SSS) mosaic, and automatic classification of a backscatter dataset from a multibeam echosounder (MBES). The maps are compared using pixel-to-pixel similarity measures derived from the literature in land remote sensing. All measures agree in presenting the MBES and SSS maps as the most similar, and the SBES and SSS maps as the least similar. The results are discussed with reference to the potential of MBES backscatter as an alternative to SSS mosaic for imagery segmentation and to the potential of joint SBES–SSS survey for improved habitat mapping. Other applications of map-similarity measures in acoustic classification of the seabed are suggested.

Impact of emissions from anthropogenic sources on satellite-derived reflectance

The present study deals with the impact of extensive anthropogenic activities associated with festivities and agricultural crop residues burning in the Indo-Gangetic Plains (IGP) on satellite-derived reflectance during November 2007. Intense smoke plumes were observed in the IRS-P4 OCM satellite data over IGP associated with agricultural crop residue burning during the study period. Terra-MODIS AOD and CALIPSO LIDAR backscatter datasets were analysed over the region to understand the spatial and temporal variation of the aerosol properties. Ground-based measurements on aerosol optical properties and black carbon (BC) mass concentration were carried out during 7–14 November 2007 over urban region of Hyderabad, India. Top of the Atmosphere (TOA) reflectance estimated from IRS-P4 Ocean Color Monitor (OCM) data showed large variations due to anthropogenic activities associated with crop residue burning and fireworks. Atmospheric corrections to OCM satellite data using 6S radiative transfer code with inputs from ground and satellite measurements could account for the variations due to differential aerosol loading. Results are discussed in this paper.

Characterizing Indian Ocean manganese nodule-bearing seafloor using multi-beam angular backscatter

Application of quantitative angular backscatter modelling to manganese nodule-bearing areas of the Central Indian Ocean Basin (CIOB) has been initiated at NIO during the year 1998. Studies were aimed to establish the suitability of seafloor backscattering in delineating seafloor parameters characteristic of nodule-rich sediments. In this paper, processed Hydrosweep multi-beam backscatter data from 45 spot locations in the CIOB (where nodule samples are available) were analysed to estimate seafloor and sediment volume roughness parameters. The application of a composite roughness model to a nodule-bearing region (6,600 km2) of the CIOB, to determine seafloor interface roughness parameters from a multi-beam backscatter dataset, shows only four power law sets. The results attest 80% of the nodule-bearing seafloor to be smooth in terms of interface roughness parameters at micro-topographic level. The sediment volume roughness parameters are dominant only in 29% of the smooth interface roughness sites. This indicates that 51% of the seafloor area possesses negligible (interface and volume) roughness. A critical analysis using pseudo-side-scan records from 12 selected locations in the study area affirms the combined importance of the seafloor interface and sediment volume roughness parameters for precise determination of manganese nodule abundance.

Wavelength dependence of backscatter by use of aerosol microphysics and lidar data sets: application to 21-µm wavelength for space-based and airborne lidars

An aerosol microphysics dataset was used to model backscatter in the 0.35-11-mum wavelength range, with the results validated by comparison with measured cw and pulsed lidar backscatter obtained during two NASA-sponsored airborne field experiments. Different atmospheric features were encountered, with aerosol backscatter ranging over 4 orders of magnitude. Modeled conversion functions were used to convert existing lidar backscatter datasets to 2.1 mum. Resulting statistical distribution shows the midtropospheric aerosol backscatter background mode of beta(2.1) to be between ~3.0 x 10(-10) and ~1.3 x 10(-9) m(-1) sr(-1), ~10-20 times higher than that for beta(9.1); and a beta(2.1) boundary layer mode of ~1.0 x 10(-7) to ~1.3 x 10(-6) m(-1) sr(-1), ~3-5 times higher than beta(9.1).

Comparison of modeled backscatter using measured aerosol microphysics with focused CW lidar data over Pacific

During NASA's GLObal Backscatter Experiment (GLOBE) II flight mission over the Pacific Ocean in May‐June 1990, extensive aerosol backscatter data sets from two continuous wave, focused CO2 Doppler lidars and an aerosol microphysics data set from a laser optical particle counter (LOPC) were obtained. Changes in aerosol loading in various air masses with associated changes in chemical composition, from sulfuric acid and sulfates to dustlike crustal material, significantly affected aerosol backscatter, causing variation of about 3 to 4 orders of magnitude. Some of the significant backscatter features encountered in different air masses were the low backscatter in subtropical air with even lower values in the tropics near the Intertropical Convergence Zone (ITCZ), highly variable backscatter in the ITCZ, mid‐tropospheric aerosol backscatter background mode, and high backscatter in an Asian dust plume off the Japanese coast. Differences in aerosol composition and backscatter for northern and southern hemisphere also were observed. Using the LOPC measurements of physical and chemical aerosol properties, we determined the complex refractive index from three different aerosol mixture models to calculate backscatter. These values provided a well‐defined envelope of modeled backscatter for various atmospheric conditions, giving good agreement with the lidar data over a horizontal sampling of ∼18,000 km in the mid‐troposphere.

Microwave inversion of root mean square height from vegetated fields: a dual frequency technique

Abstract An iterative, physically model based inversion algorithm has been used to estimate root mean square (r.m.s.) surface roughness height from radar data. collected over vegetated areas. The model is based on a discrete scatterer random media technique, and employs the distorted Born approximation to model the backscatter coefficients for a given scene. In the model, the Fresnel reflectivity (a measure of soil moisture) and surface roughness appear together in the vegetation-ground interaction term. An approach is followed that utilizes differences in their frequency response to separate the two. Sensitivity analysis shows that the change in surface reflectivity owing to the change in frequency from the L- to C-band is dominated by surface r.rn.s. height. The Fresnel reflectivity stays almost constant over this frequency interval. The inversion algorithm based on these sensitivity differences is applied to the backscatter model data from a plant canopy of soybean. Calculations show that the technique gives accurate results from a model backscatter data set that is corrupted with random noise. The inversion algorithm is also applied to Synthetic Aperture Radar (SAR) data collected over corn fields during the MACHYDRO'90 experiment in Pennsylvania, USA. There is an excellent agreement between the measured and the estimated r.m.s, surface height.

A scattering model for snow-covered sea ice

The special properties of a robust radiative transfer model for scattering from layers of inhomogeneous rough-boundary slabs are presented. The model is applied to backscattering from saline and desalinated ice. Comparisons are made at single and multiple frequencies with some of the most complete sets of measurement data available, using measured physical and electrical characteristics of the ice as inputs to the model where possible. The results show close agreement. For example, for the saline ice backscatter data set, which consisted of measurements at two like and two cross polarizations at 5 and 13.9 GHz, the agreement with model predictions is within 2 dB except at 13.9-GHz cross polarization. Backscattering from >15-cm-thick saline ice is generally dominated by scattering from the top surface while backscattering from <8-cm-thick saline ice can be strongly influenced by returns from the ice/water interface, particularly at frequencies less than about 5 GHz.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The development of the chlorinity/salinity concept in oceanography

The submerged reefs on continental margins and surrounding oceanic islands are important archives of past climates, eustatic sea-level oscillations and oceanographic processes. Australia's north eastern submerged shelf edge reefs have previously been explored, but all studies have been limited by either low-resolution single beam profiles or by their limited spatial extent. The aim of this study is to improve the understanding of the origin and development of submerged shelf edge reefs, terraces and related features on the Great Barrier Reef (GBR), and the influence of Pleistocene sea-level oscillations on their distribution and geomorphology. We investigated the first large-scale (1400 km2) 3D bathymetry and acoustic backscatter dataset of four widely-spaced sites located across ca. 650 km along the shelf edge at Ribbon Reefs 1–5, Noggin Pass, Viper Reef and Hydrographers Passage. We provide a comprehensive description and systematic classification of the shelf edge features, and constrain their spatial distribution and geomorphologic variability using a wide range of quantitative morphometrics. Fifteen features are defined, four of which are the focus of this study, including terraces, pinnacles, ridges and channels. Using modern reefs within the GBR for comparison, we interpret these as fringing reefs, patch and barrier reefs and tidal channels respectively. The influence of gross shelf geomorphology and oceanographic factors driving the observed variability within and between sites is discussed in conjunction with Mid-Late Pleistocene sea-level oscillations. We observed two distinct types of reef growth characterised by the degree of development, which we interpret as analogous to juvenile and mature modern reefs of the GBR. Juvenile reefs are very common and occur within each site at depths of less than 50 m to greater than 100 m. They are defined as discontinuous peaked barrier reefs, peaked patch reefs and fringing reefs. Mature reefs are less common and develop exclusively at a depth range of ca. 50–70 m. These reefs are defined as flat-topped continuous barrier and double barrier reefs. Through a comparison with published Mid-Late Pleistocene sea-level oscillations, we note that the depth range of mature reefs is consistent with the depth of repeated low-amplitude (< 20 m) eustatic sea-level oscillations, and independent of the relative time spent at sea-level. We conclude that repeated low-amplitude sea-level rises provide the much-needed accommodation space for vertical accretion that is not provided during stillstands, without inducing reef drowning, which can be caused by high-amplitude sea-level rise. Low-amplitude sea-level falls are also less detrimental than high-amplitude falls, in terms of habitat compression. Together, the effects of enhanced reef accretion and limited habitat compression at depths of 50–70 m have lead to a concentrated net gain in vertical relief that is not observed elsewhere on the shelf edge.