Creating the National Classification of Census Output Areas: Data, Methods and Results

The purpose of this paper is to describe and explain the processes and decisions that were involved in the creation of the National Area Classification of 2001 Census Output Areas (OAs). The project was carried out on behalf of the Office for National Statistics (ONS) by Daniel Vickers of the School of Geography, University of Leeds as part of his PhD. thesis. The paper describes the creation of the classification: selection of the variables, assembly of the classification database, the methods of standardisation and the clustering procedures, some discussion of alternative methodologies that were considered for use. The processes used for creating the clusters, their naming and description are outlined. The classification is mapped and visualised in a number of different ways. The OA Classification fits into the ONS suite of area classifications complementing published classifications at Local Authority, Health Authority and Ward levels. The classification is freely available, and can be downloaded from the ONS Neighbourhood Statistics website at www.statistics.gov.uk

Poseidon: a 2-tier Anomaly-based Intrusion Detection System

We present Poseidon, a new anomaly based intrusion detection system. Poseidon is payload-based, and presents a two-tier architecture: the first stage consists of a Self-Organizing Map, while the second one is a modified PAYL system. Our benchmarks on the 1999 DARPA data set show a higher detection rate and lower number of false positives than PAYL and PHAD

Poseidon: a 2-tier Anomaly-based Network Intrusion Detection System

We present Poseidon, a new anomaly based intrusion detection system. Poseidon is payload-based, and presents a two-tier architecture: the first stage consists of a Self-Organizing Map, while the second one is a modified PAYL system. Our benchmarks on the 1999 DARPA data set show a higher detection rate and lower number of false positives than PAYL and PHAD

Energy Efficiency in Two-Tiered Wireless Sensor Networks

We study a two-tiered wireless sensor network (WSN) consisting of $N$ access points (APs) and $M$ base stations (BSs). The sensing data, which is distributed on the sensing field according to a density function $f$, is first transmitted to the APs and then forwarded to the BSs. Our goal is to find an optimal deployment of APs and BSs to minimize the average weighted total, or Lagrangian, of sensor and AP powers. For $M=1$, we show that the optimal deployment of APs is simply a linear transformation of the optimal $N$-level quantizer for density $f$, and the sole BS should be located at the geometric centroid of the sensing field. Also, for a one-dimensional network and uniform $f$, we determine the optimal deployment of APs and BSs for any $N$ and $M$. Moreover, to numerically optimize node deployment for general scenarios, we propose one- and two-tiered Lloyd algorithms and analyze their convergence properties. Simulation results show that, when compared to random deployment, our algorithms can save up to 79\% of the power on average.Comment: 11 pages, 7 figure