Erik F. Golen

An underwater sensor allocation scheme for a range dependent environment

A series of assumptions is typically made when designing a field of passive underwater sensors. One of the more glaring is range independence throughout an operational area. It is unlikely that a large water space will have uniform acoustic characteristics throughout, i.e., the performance of a sensor will vary based upon its physical location. In an area clearance scenario, where there is no apparent target for an adversary to gravitate towards, such as a ship or a port, it is difficult to determine where the field designer should allocate sensors so that their deployment locations can be planned efficiently. To intelligently allocate sensors, a field designer could first divide an area into sectors of relatively uniform acoustics, based upon variations in acoustic characteristics throughout the area. A prediction of how often a threat submarine will visit each sector can then be made in order to increase the fields detection capabilities. In this work, an area of interest is divided into sectors of varying geographic size and acoustic characteristics and the probability of visitation to each sector by a threat submarine is determined by solving a minimax matrix game. The Game Theory Field Design (GTFD) model is proposed, which allocates sensors to sectors of relatively uniform acoustics according to the visitation probabilities of an adversary, against adversaries of varying intelligence. In a comparison with two models that do not consider these visitation probabilities and only examine either acoustic characteristics or the size of the sectors, GTFD is shown to offer a significant improvement in terms of overall field detection capability against intelligent adversaries.

Underwater Sensor Field Design using Game Theory

When designing a field of passive underwater sensors, a series of assumptions are typically made, with one of the more glaring being range independence throughout an operational area. It is unlikely that a large water space will have uniform acoustic characteristics, meaning that the performance of a sensor will vary based on its physical location. Considering that a threat may also have knowledge of the acoustics of an area, a field designer could divide the area into sectors based on changes in acoustics and predict how often a threat submarine will visit each sector of the area to increase the fields submarine detection capabilities. In this work, an operational area is split up into four quadrants with varying acoustic characteristics and the probability of visitation to each quadrant by a threat submarine is determined using game theory. A new Game Theory Field Design (GTFD) model is proposed that properly allocates sensors to each quadrant according to the visitation probabilities. When compared with a random field design model that does not consider these probabilities, GTFD is shown to offer a significant improvement in terms of detection capability.

An evolutionary approach to underwater sensor deployment

Underwater acoustic sensor deployment for military surveillance is a significant challenge due to the inherent difficulties posed by the underwater channel in terms of sensing and communications between sensors, as well as the exorbitant cost of the sensors. Thus, these sensors must be deployed as efficiently as possible. The proposed Underwater Sensor Deployment Evolutionary Algorithm (USDEA) considers six important factors that have not yet been simultaneously considered due to the ensuing complexity of the problem. Sensing capability tradeoffs are shown through simulation of two sensor network topologies, mesh and cluster.

Secure communication and signal processing in inertial navigation systems

This paper focuses on secure communication, data-analytic signal processing and robust algorithms for inertial navigation systems (INSs). Middleware, software, data processing and algorithms are studied. We examine and report high-impact technology developments as applied to current and next generations of INSs. We research advanced microelectronic, processing and software solutions. New architectures, algorithms and protocols for robustly reconfigurable networked inertial systems are studied. Examining advanced-technology inertial measurement units with application-specific integrated circuits, long-standing problems are solved. The INSs impediments are minimized by using intelligent processing schemes, consistent algorithms and software. Precision, accuracy, resolution, stability, bandwidth and dynamic range are improved by attenuating noise, reducing static error and minimizing dynamic error. We present results on secure communication for transmitting mission critical data over heterogeneous networks.

An Evolutionary Approach to Underwater Sensor Deployment

Underwater sensor deployment for military surveillance is a significant challenge due to the inherent difficulties posed by the underwater channel in terms of sensing and communications between sensors, as well as the exorbitant cost of the sensors. As a result, these sensors must be deployed as efficiently as possible. The proposed Underwater Sensor Deployment Evolutionary Algorithm considers six important factors that have not yet been simultaneously considered due to the ensuing complexity of the problem. Two principle studies are presented in this work, a benchmarking study that shows the effectiveness of the algorithm and a simulation study that outlines the inevitable effect of communications range on the sensing capabilities on an underwater sensor field.

On the effects of deployment imprecision on underwater sensor connectivity

In designing an underwater acoustic sensor network, the main bottleneck a field designer faces is the acoustic communications range of the sensors. Since communications is done at relatively high frequencies, as compared with frequencies emitted by underwater vehicles, these higher frequencies are attenuated more rapidly by the medium. Therefore, at a minimum, sensors must be deployed within communications range of each other. Unfortunately, human or mechanical error and physical aspects of the medium may lead to sensors being deployed imprecisely, causing a lack of connectivity between sensors. To mitigate such situations, this paper proposes a stochastic approach, the Effective Communications Range Calculator, for determining an effective communications range with which to design underwater sensor fields to meet the connectivity specifications of the field designer.

Underwater sensor deployment using an evolutionary algorithm

Underwater sensor deployment is a significant challenge due to the inherent difficulties posed by the underwater channel in terms of sensing and communications between sensors. In addition, monetary constraints arising from the cost of sensors and deploying them, limit the number of available sensors. As a result, these sensors must be deployed as efficiently as possible. This work presents the Underwater Sensor Deployment Evolutionary Algorithm (USDEA), which uses environmental data and several factors not simultaneously considered, due to the ensuing complexity, including sensing and communications range, to generate highly capable underwater sensor fields. Tradeoffs in field sensing capabilities are shown through a simulation study for two popular sensor network topologies, mesh and cluster.

An analytical model for the Neighbor Turn Taking MAC protocol

The neighbor turn taking (NTT) Medium Access Control (MAC) protocol is a loosely scheduled MAC, whose intended purpose is for use in wireless ad hoc networking environments where the node mobility is low. This protocol has been previously shown via simulation to perform better than IEEE 802.11 in terms of end-to-end packet latency and rate of successfully transmitted packets under saturated conditions. In this paper, we present an analytical model of the NTT MAC based upon the Bianchi station model of 802.11psilas Distributed Coordination Function to further support the claims of previous work. When comparing the analytical model developed for the NTT MAC protocol with that of 802.11, significant improvements in access delay and the probability of successful packet transmission are shown, which will ultimately provide energy savings, while attaining a per node throughput that is consistent with 802.11.

IT Curriculum: Coping with Technology Trends & Industry Demands

The field of Information Technology (IT) has evolved more rapidly over the past 15 years than ever thought possible. To keep up with industry demands, IT educators have had to react accordingly and with enough foresight to identify those trends that are short lived and those that are here to stay. In this paper, we identify a four-layer IT Stack with associated core techniques within each layer. The evolution of the core techniques over time is then discussed with respect to industry trends, changes in ACM/IEEE IT curricula, and the topics of technical oriented papers presented at the ACM SIGITE conference since 2003. Finally, a case study chronicling the evolution of an Information Technology MS program is presented, along with recommendations for modeling future IT curriculum.

A modular architecture for scalable inter-domain routing

Border Gateway Protocol (BGP) is the de facto standard for inter-domain routing. BGP faces challenges such as increases in routing table size proportional to increases in the number of networks, high convergence times, and high churn rates, among others. Modularity in routing can address several of these challenges. In this article, we discuss a modular routing architecture, its application to the current Internet, and evaluate its scalability in terms of churn rate and routing table size. Optimization opportunities offered by the modular routing architecture are discussed. Briefly, a transition approach to deploy such an architecture, through a Layer 2.5 protocol, is also presented.