The National Memorial Institute for the Prevention of Terrorism in Oklahoma City is a living memorial to the victims, survivors, family members and rescue workers affected by the April 19, 1995 bombing of the Murrah Federal Building. The Institute conducts research into the development of technologies to counter biological, nuclear and chemical weapons of mass destruction and cyberterrorism, as well as research into the social and political causes and effects of terrorism. This paper describes MIPT funded research in areas of detection, decontamination, personal protective equipment, attack simulations, treatments, awareness, improved public communication during and after an incident, as well as lessons learned from terrorist incidents.

Effective critical incident response for homeland security requires access to real-time information from many organizations. Command and control, as well as basic situational awareness, are all dependant on quickly communicating a dynamically changing picture to a variety of decision makers. For the most part, critical information management is not unfamiliar or new to the public safety community. However, new challenges present themselves when that information needs to be seamlessly shared across multiple organizations at the local, state and federal level in real-time. The homeland security problem does not lend itself to the traditional military joint forces planning model where activities shift from a deliberate planning process to a crisis action planning process. Rather, the homeland security problem is more similar to a traditional public safety model where the current activity state moves from complete inactivity or low-level attention to immediate crisis action planning. More often than not the escalation occurs with no warning or baseline information. This paper addresses the challenges of sharing critical incident information and the impacts new technologies will have on this problem. The value of current and proposed approaches will be critiqued for operational value and areas will be identified for further development.

Since April 2001, the Oklahoma City National Memorial Institute for the Prevention of Terrorism has funded an effort by Hicks &Associates, Inc. and the Terrorism Research Center, Inc., aimed ultimately at improving local, state, and federal emergency responders’ capabilities for mitigating the effects of chemical, biological, radiological, nuclear or explosive/ incendiary (CBRNE) terrorism. This effort, titled “Project Responder,” began by developing an understanding of how state and local responders view their current capabilities, shortfalls, and needs. This paper discusses some of the results of this first phase of the effort that has resulted in a comprehensive report titled "Emergency Responders’ Needs, Goals, and Priorities." This paper addresses two of the capabilities from that report which we believe are of most interest to this conference. There are ten other capabilities discussed in the report, which may also be of interest.

The challenge of obtaining an adequate environmental support system to help mitigate the effects of various terrorist generated plumes is articulated and a fiscally responsible solution is presented. A substantially improved national system of upper air data observing systems serves as a powerful information source prior to a terrorist event. A mobile tactical observing system for measuring the environment and for measuring the composition and intensity of the plume is implemented immediately following an event. Only proven and tested technologies are used. Program costs, benefits for the fight against terrorism, and multiple benefits to other aspects of the economy are summarized.

The sensitivity of the eye’s reaction to a wide variety of chemicals/toxins and its role as a gauge for internal homeostasis (e.g., cardiovascular and neurophysiological imbalances) has been extensively researched via many scientific disciplines. New techniques and equipment are both harnessing and utilizing this information to define a modern approach to the field of non-invasive early detection of a vast range of physical abnormalities, injuries, and illnesses. Early detection provides an invaluable tool in the subsequent success of treating such conditions. The application of these techniques to the detection of exposure to chemical threat agents such as organophosphate nerve agents and cyanide provides an important advancement in the ability to limit the deleterious effects of these agents. The Ocular Scanning Instrumentation (OSI) technology involves the use of an automated device for the continuous or programmed monitoring of optically apparent characteristic(s) and attributes of the eye that may serve as an early-warning system for possible complications based upon generalized information obtained from ocular biomarkers. Described herein is the analysis of primary ocular biomarkers for organophosphate (miosis) and cyanide (venous blood coloration) exposure.

The Army Research Laboratory has developed body-contacting acoustic sensors that detect diverse physiological sounds such as heartbeats and breaths, high quality speech, and activity. These sensors use an acoustic impedance-matching gel contained in a soft, compliant pad to enhance the body borne sounds, yet significantly repel airborne noises due to an acoustic impedance mismatch. The signals from such a sensor can be used as a microphone with embedded physiology, or a dedicated digital signal processor can process packetized data to separate physiological parameters from voice, and log parameter trends for performance surveillance. Acoustic sensors were placed inside soldier helmets to monitor voice, physiology, activity, and situational awareness clues such as bullet shockwaves from sniper activity and explosions. The sensors were also incorporated into firefighter breathing masks, neck and wrist straps, and other protective equipment. Heart rate, breath rate, blood pressure, voice and activity can be derived from these sensors (reports at www.arl.army.mil/acoustics). Having numerous sensors at various locations provides a means for array processing to reduce motion artifacts, calculate pulse transit time for passive blood pressure measurement, and the origin of blunt/penetrating traumas such as ballistic wounding. These types of sensors give us the ability to monitor soldiers and civilian emergency first-responders in demanding environments, and provide vital signs information to assess their health status and how that person is interacting with the environment and mission at hand. The Objective Force Warrior, Scorpion, Land Warrior, Warrior Medic, and other military and civilian programs can potentially benefit from these sensors.

The behavior of cyber-terrorists and other cyber-adversaries can be modeled to identify critical phases of their behavior yielding insights into necessary behavior for them to accomplish their mission. Focusing technology on thwarting the adversary mission rather than particular exploits is a critical component of successful defense-in-depth. This paper presents the results of modeling workshops that led to a set of experiments that successfully thwarted a cyber-adversary’s mission.

We describe a tool to help exercise and train IT managers who make decisions about IP networks in the midst of cyber calamity. Our tool is interactive, centered around a network simulation. It includes various modes of communications one would use to make informed decisions. Our tool is capable of simulating networks with hundreds of components and dozens of players. Test indicate that it could support an exercise an order of magnitude larger and more complex.

Signaling System 7 (SS7) is vital to signaling and control in America's public telephone networks. This paper describes a class of attacks on SS7 networks involving the insertion of malicious signaling messages via compromised SS7 network components. Three attacks are discussed in detail: IAM flood attacks, redirection attacks and point code spoofing attacks. Depending on their scale of execution, these attacks can produce effects ranging from network congestion to service disruption. Methods for detecting these denial-of-service attacks and mitigating their effects are also presented.

In this paper we address the reliable transmission of security-enabled multimedia data over the internet which is becoming increasingly vulnerable to a variety of cyber-attacks. Due to their real-timeliness aspect, multimedia data in Internet mostly uses User Datagram Protocol(UDP) as the transport media as opposed to the Transport Control Protocol (TCP). UDP is inherently an unreliable transport media that results in certain unacknowledged packet losses. Multimedia applications usually can tolerate some packet losses for its rendering at the receiver side. But, for the security-enhanced multimedia that we are talking about, reliability of reception of most of the packets within a certain tolerance time need to be guaranteed. This is where we come in with a new protocol that ensures packet-level reliability as well as stream-level authentication of multimedia.

Identification of an Internet worm is a manual process where security analysts must observe and analyze unusual activity on multiple firewalls, intrusion-detection systems or hosts. A worm might not be positively identified until it already has spread to most of the Internet, eliminating many defensive options. In this paper, we present an automated system that can identify active worms seconds or minutes after they first begin to spread, a necessary precursor to halting the spread of a worm, rather than simply cleaning up afterward. Our implemented system collects ICMP Unreachable messages from instrumented network routers, identifies those patterns of unreachable messages that indicate malicious scanning activity, and then searches for patterns of scanning activity that indicate a propagating worm. In this paper, we examine the problem of active worms, describe our ICMP-based detection system, and present simulation results that illustrate the speed with which it can detect a worm.

Converged network security is extremely challenging for several reasons; expanded system and technology perimeters, unexpected feature interaction, and complex interfaces all conspire to provide hackers with greater opportunities for compromising large networks. Preventive security services and architectures are essential, but in and of themselves do not eliminate all threat of compromise. Attack management systems mitigate this residual risk by facilitating incident detection, analysis and response. There are a wealth of attack detection and response tools for IP networks, but a dearth of such tools for wireless and public telephone networks. Moreover, methodologies and formalisms have yet to be identified that can yield a common model for vulnerabilities and attacks in converged networks. A comprehensive attack management system must coordinate detection tools for converged networks, derive fully-integrated attack and network models, perform vulnerability and multi-stage attack analysis, support large-scale attack visualization, and orchestrate strategic responses to cyber attacks that cross network boundaries. We present an architecture that embodies these principles for attack management. The attack management system described engages a suite of detection tools for various networking domains, feeding real-time attack data to a comprehensive modeling, analysis and visualization subsystem. The resulting early warning system not only provides network administrators with a heads-up cockpit display of their entire network, it also supports guided response and predictive capabilities for multi-stage attacks in converged networks.

Project Guardian will examine technology policy issues that are associated with maintaining our civil liberties. This multidisciplinary effort will provide a public forum to examine the balance between civil liberties and national security. Project Guardian will endeavor to provide practical and workable recommendations to policymakers for accomplishing both the projection of our civil liberties, and the enabling technology to enhance the aggressive pursuit of terrorists.

Bridging the gap between low level ontologies used for data acquisition and high level ontologies used for inference is essential to enable the discovery of high-level links between low-level entities. This is of utmost importance in many applications, where the semantic distance between the observable evidence and the target relations is large. Examples of these applications would be detection of terrorist activity, crime analysis, and technology monitoring, among others. Currently this inference gap has been filled by expert knowledge. However, with the increase of the data and system size, it has become too costly to perform such manual inference. This paper proposes a semi-automatic system to bridge the inference gap using network correlation methods, similar to Bayesian Belief Networks, combined with hierarchical clustering, to group and organize data so that experts can observe and build the inference gap ontologies quickly and efficiently, decreasing the cost of this labor-intensive process. A simple application of this method is shown here, where the co-author collaboration structure ontology is inferred from the analysis of a collection of journal publications on the subject of anthrax. This example uncovers a co-author collaboration structures (a well defined ontology) from a scientific publication dataset (also a well defined ontology). Nevertheless, the evidence of author collaboration is poorly defined, requiring the use of evidence from keywords, citations, publication dates, and paper co-authorship. The proposed system automatically suggests candidate collaboration group patterns for evaluation by experts. Using an intuitive graphic user interface, these experts identify, confirm and refine the proposed ontologies and add them to the ontology database to be used in subsequent processes.

This paper describes the application of sequence learning to the domain of terrorist group actions. The goal is to make accurate predictions of future events based on learning from past history. The past history of the group is represented as a sequence of events. Well-established sequence learning approaches are used to generate temporal rules from the event sequence. In order to represent all the possible events involving a terrorist group activities, an event taxonomy has been created that organizes the events into a hierarchical structure. The event taxonomy is applied when events are extracted, and the hierarchical form of the taxonomy is especially useful when only scant information is available about an event. The taxonomy can also be used to generate temporal rules at various levels of abstraction. The generated temporal rules are used to generate predictions that can be compared to actual events for evaluation. The approach was tested on events collected for a four-year period from relevant newspaper articles and other open-source literature. Temporal rules were generated based on the first half of the data, and predictions were generated for the second half of the data. Evaluation yielded a high hit rate and a moderate false-alarm rate.

The City of Houston is continuously improving its preparedness for disasters and terrorism. This preparation requires strong and clear leadership. This includes a designated individual to lead the region’s preparation in the health and medical arena. An effective leader requires an effective command and control center. Real-time information on the situation is imperative.

Public health surveillance is the ongoing, systematic collection, analysis, interpretation, and dissemination of data regarding a health-related event for use in public health action to reduce morbidity and mortality and to improve health by effective response management and coordination. As new pressures for early detection of disease outbreaks have arisen, particularly for outbreaks of possible bioterrorism (BT) origin, and as electronic health data have become increasingly available, so has the demand for public health situation awareness systems. Although these systems are valuable for early warning of public health emergencies, there remains the cost of developing and managing such large and complex systems and of investigating inevitable false alarms. Whether these systems are dependable and cost effective enough and can demonstrate a significant and indispensable role in detection or prevention of mass casualty events of BT origin remains to be proven. This article will focus on the complexities of design, analysis, implementation and evaluation of public health surveillance and situation awareness systems and, in some cases, will discuss the key technologies being studied in Center for Biosecurity Informatics Research at University of Texas, Health Science Center at Houston.

Silver physical development, a now-abandoned technique used for developing photographic film or paper, is one of the most powerful methods for visualizing latent prints on paper. The method develops the water-insoluble components in the print residue. These components include the “fats and oils” or lipids found on the skin of fingers. The resulting developed print, referred to as a silver physically developed (Ag-PD) print, is made up of (gray to black) silver particles adhered to the fingerprint residue. Such prints are usually intensified (made darker) with a hypochlorite treatment. This process converts silver to silver oxide making the Ag-PD print become a Ag₂O-PD prints. Often such (Ag-PD or Ag₂O-PD) prints are found on areas with heavy or patterned printing making them difficult to see. This work resolves this problem by chemically lightening the print and darkening (suppressing) the interfering background.

Law Enforcement personnel are faced with new challenges to rapidly assess the credibility of statements made by individuals in airports, border crossings, and a variety of environments not conducive to interviews. New technologies may offer assistance to law enforcement personnel in the interview and interrogation process. Additionally, homeland defense against terrorism challenges scientists to develop new methods of assessing truthfulness and credibility in humans. Current findings of four advanced research projects looking at emerging technologies in the credibility assessment are presented for discussion. This paper will discuss research efforts on four emerging technologies now underway at DoDPI and other institutions. These include: (1) Thermal Image Analysis (TIA); (2) Laser Doppler Vibrometry (LDV); (3) Eye Movement based Memory Assessment (EMMA); and (4) functional Magnetic Resonance Imaging (fMRI). A description each technique, the current state of these research efforts, and an overview of the potential for each of these emerging technologies will be provided.

A comprehensive study and comparison is underway using biological detectors and instrumental methods for the rapid detection of ignitable liquid residues (ILR) and high explosives. Headspace solid phase microextraction (SPME) has been demonstrated to be an effective sampling method helping to identify active odor signature chemicals used by detector dogs to locate forensic specimens as well as a rapid pre-concentration technique prior to instrumental detection. Common ignitable liquids and common military and industrial explosives have been studied including trinitrotoluene, tetryl, RDX, HMX, EGDN, PETN and nitroglycerine. This study focuses on identifying volatile odor signature chemicals present, which can be used to enhance the level and reliability of detection of ILR and explosives by canines and instrumental methods. While most instrumental methods currently in use focus on particles and on parent organic compounds, which are often involatile, characteristic volatile organics are generally also present and can be exploited to enhance detection particularly for well-concealed devices. Specific examples include the volatile odor chemicals 2-ethyl-1-hexanol and cyclohexanone, which are readily available in the headspace of the high explosive composition C-4; whereas, the active chemical cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX) is not. The analysis and identification of these headspace 'fingerprint' organics is followed by double-blind dog trials of the individual components using certified teams in an attempt to isolate and understand the target compounds to which dogs are sensitive. Studies to compare commonly used training aids with the actual target explosive have also been undertaken to determine their suitability and effectiveness. The optimization of solid phase microextraction (SPME) combined with ion trap mobility spectrometry (ITMS) and gas chromatography/mass spectrometry/mass spectrometry (GC/MSⁿ) is detailed including interface development and comparisons of limits of detection. These instrumental methods are being optimized in order to detect the same target odor chemicals used by detector dogs to reliably locate explosives and ignitable liquids.

The importance of small amounts of glass and paint evidence as a means to associate a crime event to a suspect or a suspect to another individual has been demonstrated in many cases. Glass is a fragile material that is often found at the scenes of crimes such as burglaries, hit-and-run accidents and violent crime offenses. Previous work has demonstrated the utility of elemental analysis by solution ICP-MS of small amounts of glass for the comparison between a fragment found at a crime scene to a possible source of the glass. The multi-element capability and the sensitivity of ICP-MS combined with the simplified sample introduction of laser ablation prior to ion detection provides for an excellent and relatively non-destructive technique for elemental analysis of glass fragments. The direct solid sample introduction technique of laser ablation (LA) is reported as an alternative to the solution method. Direct solid sampling provides several advantages over solution methods and shows great potential for a number of solid sample analyses in forensic science. The advantages of laser ablation include the simplification of sample preparation, thereby reducing the time and complexity of the analysis, the elimination of handling acid dissolution reagents such as HF and the reduction of sources of interferences in the ionization plasma. Direct sampling also provides for essentially “non-destructive” sampling due to the removal of very small amounts of sample needed for analysis. The discrimination potential of LA-ICP-MS is compared with previously reported solution ICP-MS methods using external calibration with internal standardization and a newly reported solution isotope dilution (ID) method. A total of ninety-one different glass samples were used for the comparison study using the techniques mentioned. One set consisted of forty-five headlamps taken from a variety of automobiles representing a range of twenty years of manufacturing dates. A second set consisted of forty-six automotive glasses (side windows and windshields) representing casework glass from different vehicle manufacturers over several years was also characterized by RI and elemental composition analysis. The solution sample introduction techniques (external calibration and isotope dilution) provide for excellent sensitivity and precision but have the disadvantages of destroying the sample and also involve complex sample preparation. The laser ablation method was simpler, faster and produced comparable discrimination to the EC-ICP-MS and ID-ICP-MS. LA-ICP-MS can provide for an excellent alternative to solution analysis of glass in forensic casework samples. Paints and coatings are frequently encountered as trace evidence samples submitted to forensic science laboratories. A LA-ICP-MS method has been developed to complement the commonly used techniques in forensic laboratories in order to better characterize these samples for forensic purposes. Time-resolved plots of each sample can be compared to associate samples to each other or to discriminate between samples. Additionally, the concentration of lead and the ratios of other elements have been determined in various automotive paints by the reported method. A sample set of eighteen (18) survey automotive paint samples have been analyzed with the developed method in order to determine the utility of LA-ICP-MS and to compare the method to the more commonly used scanning electron microscopy (SEM) method for elemental characterization of paint layers in forensic casework.

The threat of biological agents to soldiers and the civilian community was amply demonstrated in the fall of 2001. We are examining the feasibility of using surface-enhanced Raman spectroscopy (SERS) to detect and identify bacteria. In order to use SERS for bacterial detection and identification, it is necessary to determine the most appropriate type of SERS substrate to use. We are examining gold colloids in suspension, immobilized gold colloids, electrochemically roughened gold, periodic particle arrays (PPA), and film over nanosphere substrates (FONS). Briefly, PPA’s are prepared by depositing gold or silver in the interstitial spaces in a close-packed array of polystyrene nanospheres, while FONS are prepared by depositing approximately half a nanosphere diameter of gold or silver on top of a close-packed array of polymer nanospheres. We are evaluating each of these substrate types to determine which will have a high affinity for bacteria, whether we need to modify the surface of the substrate to attract bacteria, and the degree to which each type of substrate enhances the Raman scattering from the bacterial targets. We will present the results of our initial evaluations of substrates and the spectra obtained for several species of bacteria.

The need for the development of a low-cost, low-energy, portable remote sensor of hazardous chemicals for first responders and facility protection has been recognized. Differential absorption radiometry (DAR) based on uncooled detectors has been identified as a possible solution. However, uncooled detectors have lower detectivity than cooled detectors and thus require efficient light management. Two prototype DARs, one consisting of two cryogenically cooled HgCdTe detectors and the other consisting of two LiTaO₃ pyroelectric detectors, designed to detect methanol vapor, were built and tested in the laboratory to compare their relative performance by measuring detectivity limits under controlled conditions. With ΔT = 8.3 K between the methanol vapor and a radiation source having an emissivity of ε_s = 0.92, methanol detection limits of 3.14x10^-4 atm-cm and 3.5x10^-3 atm-cm were projected for the HgCdTe and pyroelectric based DARs with similar optics, respectively, assuming that a minimum SNR less than or equal to 5 is required for positive detection and identification. Evaluation of the individual detectors in each DAR demonstrated that the detector limited noise equivalent temperature difference (NETD) for the HgCdTe detector was 381 μK whereas the detector limited NETD for the pyroelectric detector was 110 mK. With a 1 s exposure to the source, temperature fluctuations in the environment increased the NETD of the HgCdTe detector to 31.0 mK whereas the NETD of the pyroelectric detector was 115 mK. These results indicated that the advantage of the HgCdTe based DAR relative to the pyroelectric based DAR is much smaller than the advantage projected by their detector limited characteristics such as D*. Thus for remote sensing applications where cost is critical, the use of pyroelectric detectors can provide acceptable performance characteristics when the signal incident on the detector is increased only by x10 relative to the signal required for similar sensitivity using HgCdTe detectors.

Quantum Magnetics is developing a system based on magnetic resonance (MR), combined with a proprietary technology, to screen for chemical agents in nonmetallic containers, without the need to open the container. It derives from the successful design and testing of a similar system for detecting liquid explosives. Preliminary measurements indicate that the system promises to quickly screen for many chemical agents and to offer an unambiguous hazard/safe result. The system will be designed to be portable and easy to operate, to need minimal human interpretation, and to be ideal for operation at checkpoints, government building, airports, and the like.

We are investigating the utility of UV light emitting diodes (LEDs) as the excitation source for fluorescence-based biological agent detection. These LEDs may enable the development of small and low-cost biological agent detectors. We have designed, and are currently fabricating, a test bed using UV LEDs for detecting biological agent aerosols. Using an experimental apparatus, we have measured the elastic scattering and fluorescence signals from single bacterial spores illuminated by low-power 408-nm laser diode radiation.

In battlefield situations, as well as other distributed sensing applications, networks of small, low-cost wireless sensors require short-range communication links that are low-power and difficult to detect at standoff distances (covert). Currently, short-range (< 100m) state-of-the-art ground-to-ground radio frequency (RF) links require line-of-sight for reliable connectivity, and may require 50 to 100 times more power for the transceiver electronics than what is radiated by the transmitter. Furthermore, the RF transmit power necessary to overcome R⁴ losses near the ground makes the links easily detectable at stand-off ranges unless sophisticated waveforms or highly directive antennas are employed, both of which are inconsistent with low-cost, low-power transceivers. In contrast, baseband optical communication links in the mid-ultraviolet (UV) band can exploit atmospheric scattering to achieve non line-of-sight (NLOS) operation with low-power transceivers at wavelengths that are difficult to detect at stand-off ranges. This paper reviews NLOS UV communication concepts, phenomenology, and the evolution of device technology. A portable communications test bed is described, and recent outdoor tests with 340nm semiconductor emitters are summarized. An indoor FM voice link is described, as an example of the compact form-factor that can be achieved with current technology. The paper concludes with a discussion of potential applications.

America faces the threat of biological attack. Stopping such attacks requires the fast detection of pathogens. Fluorescence of key biological substances provides a real-time technique for detecting airborne pathogens. Pacific Scientific Instruments has already demonstrated that Bioni, a bio-aerosol sensor based on a CW UV-emitting AlGaN diode laser, can detect within seconds the dispersal of threat organisms in postal sorting facilities and other settings. Minimization of false positives is especially important in bio-threat detection, since false positives can lead to undue public alarm, stoppages of work, and costly clean-ups. Although Bioni has proven itself as a fast and sensitive trigger, its selectivity is limited by its single-wavelength excitation and single-band fluorescence detection. In this paper, we describe the development of BioLert, which uses simultaneous excitation and detection at multiple wavelengths to improve specificity and guard against false positives. Initial experimental results on the detection of individual spores of Bacillus globigii (BG), as well as discrimination against inert aerosols, will be discussed.

The BioBadge is a biological dosimeter product based on a personal collection device developed by MesoSystems Technology. Designed to be worn by individuals in potentially biologically hazardous environments, the BioBadge allows for real-time collection, concentration, and analysis of biological agents present in the air. It provides a measure of the wearer’s exposure, providing a means for determining the characteristic and extent of human health threat. In this article, the basic technology that comprises the BioBadge is discussed. Experimental results are presented which explore the performance of this technology. Also included is a simple example to illustrate the use of the wearable sampler.

Sensors that are exceptionally sensitive with real-time outputs and minimal consumption of reagents are needed to continuously monitor air and water against bioterrorist incidents. Amplifying fluorescent polymers (AFP) provide exceptionally sensitive real-time reagentless sensor platforms as applied to detection of nitroaromatic explosives. This platform technology has the potential to be adapted to detect biological warfare (BW) agents by covalently attaching the 5’ end of stem-loop molecular beacons to AFP as DNA hybridization signal transduction switches. Molecular beacons with loop sequences specific for sequence signatures of a target BW agent are configured with a quencher on the end of the 3’ arm of the stem-loop. The AFP is quenched in the absence of target DNA, but upon hybridization with target the stem is melted, the duplex loop extended, and the AFP dequenched. This signal transduction is reversible upon removal of the target sequence with the molecular beacon reforming the stem-loop conformation. Proof-of-concept research has demonstrated that molecular beacons for signature sequences of Francisella tularensis result in correct identification of the presence of this agent in samples, but no false positives were seen with Escherichia coli.

Unattended Ground Sensors (UGS) have proven to be invaluable in various military missions. Specifically, UGS systems add significantly to the capability and security of reconnaissance and surveillance units during military operations by monitoring the battlefield. Recent initiatives for Homeland Defense target the use of DoD technologies for use in the public sector for Offices under the Department of Homeland Defense. UGS systems can be utilized for Homeland Defense for perimeter security, surveillance, tracking, and intrusion detection. This paper depicts the use of present UGS technologies for use in Homeland Defense applications.

This paper describes a new patent-pending digital-ultrasonic sensor network technology, which provides a “security protection sphere” around the authorized user(s) and the infrastructure system or system(s) to achieve C3I in Homeland Security and Law Enforcement Applications. If the system device, such as a firearm, a secure computer, PDA, or vehicle is misplaced, stolen or removed from the security protective sphere, an alarm is activated. A digital-ultrasonic sensor/tag utilizes the system’s physical structure to form a 2 to 20 Meter programmable protection sphere around the device and the authorized user. In addition, the system allows only authorized users to utilize the system, thereby creating personalized weapons, secure vehicle access or secure computer hardware. If an unauthorized individual accesses the system device, the system becomes inoperative and an alarm is activated. As the command and control, the authorized individual is provided a secure wristwatch/PDA. Access control is provided by "touch" and is controlled through the wristwatch/PDA/smartcard with a unique digital-ultrasonic coding and matching protocol that provides a very high level of security for each wireless sensor.

Seismic footstep detection based systems for homeland security applications are an important additional layer to perimeter protection and other security systems. This article reports seismic footstep signal characterization for different signal to noise ratios. Various footstep signal spectra are analyzed for different distances between a walking person and a seismic sensor. We also investigated kurtosis of the real footstep signals under various environmental and modeled noises. We also report on the results of seismic signal summation from separate geophones. A seismic signal sum spectrum obtained was broader than that obtained from a single sensor. The peak of the seismic signal sum was broader than that from the footstep signal of the single sensor. The signal and noise spectra have a greater overlap for a seismic signal sum than that from a single sensor. Generally, it is more difficult to filter out the noise from the sum of the seismic signals. We show that the use of the traditional approach of spectrum technology and/or the statistical characteristics of signal to noise of reliable footstep detection systems is not practical.

With the number of small, inexpensive Unmanned Air Vehicles (UAVs) increasing, it is feasible to build multi-UAV sensing networks. In particular, by using UAVs in conjunction with unattended ground sensors, a degree of persistent sensing can be achieved. With proper UAV cooperation algorithms, sensing is maintained even though exceptional events, e.g., the loss of a UAV, have occurred. In this paper a cooperation architecture is described that allows multiple UAVs to perform coordinated, persistent sensing with unattended ground sensors over a wide area. This architecture automatically adapts the UAV paths so that on the average, the amount of time that any sensor has to wait for a UAV revisit is minimized. We also describe the Simulation, Tactical Operations and Mission Planning (STOMP) software. STOMP is designed to help simulate and operate distributed sensor networks where multiple UAVs are used to collect data.

It has often been observed that the most daunting aspect of any crisis response is managing the "unknown unknowns" that inevitably plague incident commanders and emergency personnel at all levels responsible for life and death decisions on a minute by minute basis. In structural collapse situations, for example, rescue crews rarely have even a coarse picture of the number or disposition of people or material scattered amongst the twisted beams and piles of concrete that typically entomb would-be survivors. How can the incident commander decide which beam to lift or even which section of the building to search first in the absence of information of what lies beneath. Even the slightest tug on a concrete slab can collapse potential life harboring void spaces below killing potential survivors in the process. In deploying mobile robots to assist in rescue operations we combined the traditional advantages of machine immunity to fatigue, hazardous materials and environmental controls, with the mechanical design freedom that allowed small platforms to penetrate deep into rubble to expand both situational awareness and operational influence of rescue services at the World Trade Center and mountainous snow-bound caves in Afghanistan. We learned a great deal from these experiences with regard to robot emloyment and design. This paper endeavors to share a few of our more prominent lessons learned regarding portable robot mobility as a means to manage user expectations and stimulate more innovative and adaptive design.

Urban search and rescue (USAR) is one of the most dangerous and time-critical non-wartime activities. Researchers have been developing hardware and software to enable robots to perform some search and rescue functions so as to minimize the exposure of human rescue personnel to danger and maximize the survival of victims. Significant progress has been achieved, but much work remains. USAR demands a blending of numerous specialized technologies. An effective USAR robot must be endowed with key competencies, such as being able to negotiate collapsed structures, find victims and assess their condition, identify potential hazards, generate maps of the structure and victim locations, and communicate with rescue personnel. These competencies bring to bear work in numerous sub-disciplines of intelligent systems (or artificial intelligence) such as sensory processing, world modeling, behavior generation, path planning, and human-robot interaction, in addition to work in communications, mechanism design and advanced sensors. In an attempt to stimulate progress in the field, reference USAR challenges are being developed and propagated worldwide. In order to make efficient use of finite research resources, the robotic USAR community must share a common understanding of what is required, technologically, to attain each competency, and have a rigorous measure of the current level of effectiveness of various technologies. NIST is working with partner organizations to measure the performance of robotic USAR competencies and technologies. In this paper, we describe the reference test arenas for USAR robots, assess the current challenges within the field, and discuss experiences thus far in the testing effort.

In recent years, there has been increased emphasis on remote sensing as an alternative to traditional systems that rely heavily on the deployment of extensive manpower for surveillance and security. Unattended sensors provide for continuous, widespread coverage and are more cost-effective than the deployment of personnel for many Homeland Defense and Law Enforcement applications. Such applications include international border security, perimeter defense of military installations, nuclear and other critical facilities, as well as detection of chemical or bio-terrorism attacks. Sensor technology has experienced significant advances in recent years. However, remote sensors still rely on batteries, which are short-lived and notoriously unreliable, thereby potentially compromising Homeland Security. There is a critical need for a long-term reliable energy source to power remote sensor networks. Such a battery-free alternative technology has been developed by Ambient Control Systems. Ambient has developed an advanced mid-door photovoltaic technology, which converts light to energy over a wide range of lighting conditions. The energy is then stored in supercapacitors, a highly robust, long-term storage medium. Ambient's advanced energy management technology can power remote sensor and control systems 24 hours/day, 7 days/week for over 20 years, without batteries and with virtually no maintenance, providing for ongoing monitoring and control.

TNO Human Factors in the Netherlands developed a prototype apparatus for testing the image quality of X-ray Baggage Screening Systems: BAXSTER. BAXSTER stands for BAggage X-ray Screening TesteR. The test has a variety of applications, e.g. support by the choice of optimal screening systems for airport security, comparison of competing X-ray systems, delivery tests and routine tests. Advantages over existing tests are (1) a strong relationship with real object recognition, (2) accurate and objective test results, and (3) ease of use: performing a test is almost as easy as doing an eye test at the optometrist. BAXSTER is based on the patented TOD (Triangle Orientation Discrimination) test method, which is well-suited for standardization, and development of the test apparatus was funded by the US FAA/TSA (Transportation Security Administration). The apparatus consists of two parts. The first part is a set of test charts containing triangular test patterns of various metals of different sizes and thicknesses. These charts are placed in a frame that is scanned by the X-ray system like a regular baggage item. The operator has to judge the orientation of these patterns on the X-ray image. The second part is a laptop with peripherals and software that controls and analyses the test. The result of a test is a set of performance indicators (relating to detection, resolution, penetration, wire detection and wire penetration) for the entire system, including the display, the operator and the effect of environmental conditions. No (electronic) connection with the X-ray system is required. The effectiveness of automatic object detection and material discrimination through dual-energy X-ray analysis cannot be tested with BAXSTER. In conclusion: with BAXSTER the image quality of X-ray Baggage Screening Systems can be tested easily and objectively.

As technologies emerge that have the potential to significantly improve the detection and recognition of concealed weapons and objects on personnel, the ultimate effectiveness of these systems is still reliant on the performance of the operator of that system. This paper will report the work undertaken to evaluate and optimise the effectiveness of a millimetre wave (MMW) system. This was achieved through an extensive series of trials carried out at a large UK airport and also under more controlled field conditions. The paper will discuss the work carried out to develop a simple and usable human-computer interface, and the development and implementation of the training program. This training program was based on a detailed task analysis, leading to the identification of competencies required for effective weapon detection and recognition. Ultimately, however, the effectiveness of emerging technologies, such as the MMW, needs to be empirically demonstrated. To that end we will report the results of comprehensive psychophysical performance assessments that has led, probably for the first time, to performance metrics for a MMW system that combine the performance of the system with the performance of the user. For emerging technologies to be truly successful a collaborative and co-operative approach from technologists, regulators, airport authorities, human factors specialists and occupational psychologists is required. The work reported will emphasise the importance of the collaboration that has occurred.

Conventional concealed weapons detection portals, deployed worlwide at airports, governent buildings, courthouses, and other security critical facilities, are challenged by today's need for stringent and effective entry point screening. Modern threats, like exotic lightweight handguns, are becoming increasingly difficult to detect. Conventional portals do little, if anything, to assist security personnel in resolving the true nature of a potential threat. Systems that rely on blind operator intervention for alarm resolution invite too much human error so security is ultimately compromised. These systems do not instill confidence in the operator or the general public and thus do not present the necessary deterrent to those with sinister intent. Increased detection and improved discrimination do not adequately advance the utility of these security tools. High precision alarm object location information presented to the operator will result in the rapid resolution of the potential threat. Providing this information to the person under scrutiny via a static or streaming video image can enable self-divesting of the offending item without the need for security personnel intervention. Robust detection, effective discrimination, and precise object location information will result in superior entry point screening operations.

Recent advances in passive and active imaging sensor technology offer the potential to detect weapons that are concealed underneath a person's clothing or carried along in bags. Although the concealed weapons can sometimes easily be detected, it can be difficult to perceive their context, due to the non-literal nature of these images. Especially for dynamic crowd surveillance purposes it may be impossible to rapidly asses with certainty which individual in the crowd is the one carrying the observed weapon. Sensor fusion is an enabling technology that may be used to solve this problem. Through fusion the signal of the sensor that depicts the weapon can be displayed in the context provided by a sensor of a different modality. We propose an image fusion scheme in which non-literal imagery can be fused with standard color images such that the result clearly displays the observed weapons in the context of the original color image. The procedure is such that the relevant contrast details from the non-literal image are transferred to the color image without altering the original color distribution of this image. The result is a natural looking color image that fluently combines all details from both input sources. When an observer who performs a dynamic crowd surveillance task, detects a weapon in the scene, he will also be able to quickly determine which person in the crowd is actually carrying the observed weapon (e.g. "the man with the red T-shirt and blue jeans"). The method is illustrated by the fusion of thermal 8-12 μm imagery with standard RGB color images.

Conventional metal detectors require people to walk through a door-like opening that houses the detection system. Typically, each person must be scanned individually. This creates a “choke point,” and long lines form at the screening point. This paper describes a metal detection sensor system that could screen large crowds of people more efficiently. The new system is called the Wide-Area Metal Detection (WAMD) sensor system. This sensor system is composed of a spatially distributed metal detector and a video surveillance system. The sensor system is designed to continually screen an area and reduce the need for each person to be examined separately.

A general description of backscatter x-ray imaging is provided as well as sample images from systems that can be applied to various homeland defense missions. These missions include detection of concealed weapons, thru-wall imaging, explosives detection, contraband detection in small and large containers, and rapid single-sided scanning of stationary and moving targets.

ITT Industries Night Vision has developed a new high-performance image intensifier for use in existing aviation and ground night vision systems. This intensifier, called the "Pinnacle" by ITT, provides substantial performance increases in low light detection, high light resolution, and intra-scene dynamic range (the ability to see detail in dark areas of a scene where bright cultural lighting is present -- for example, into a dark alley where streetlights are also in the scene). The new Pinnacle intensifier can be used in all aviation and ground systems that currently accept 18 mm image intensifiers. The performance improvements offered in the Pinnacle intensifier are made possible by three factors: (1) a new high-performance micro-channel plate (MCP), (2) a newly designed gating power supply, and (3) manufacturing processes that have been optimized through design-of-experiments and six-sigma methods. With the higher signal-to-noise, resolution, and bright-light halo performance levels, the Pinnacle image intensifier substantially outperforms all previously fielded intensifiers, and greatly enhances the user's ability to operate at night.

This paper describes a covert means of photographing the interiors of moving vehicles at all times of the day or night through clear or tinted windows. The system is called the Georgia Vehicle Occupancy System (GVOS). It utilizes an infrared (IR) strobe light to illuminate passenger and cargo compartments through side windows or the windshield. A high-speed, digital, infrared camera records the images and is capable of providing clear, stop-motion images of the interiors of vehicles moving at highway speeds. A human screener can view these images, or pattern recognition algorithms can be used to count the number of passengers, identify particular individuals, or screen the types and placement of cargo. Examples of vehicle interior images recorded at highway speeds are shown. For homeland security, such a system can be used to screen vehicles entering military bases or other sensitive sites or it can be implemented on highways for identifying and tracking suspicious individuals.

Phased array antenna systems, which support high pulse rates and high transmit power, are well suited for radar and large-scale surveillance. Sensors and communication systems can function as the eyes and ears for ballistic missile defense applications, providing early warning of attack, target detection and identification, target tracking, and countermeasure decision. In such applications, active array radar systems that contain solid-state transmitter sources and low-noise preamplifiers for transmission and reception are preferred over the conventional radar antennas, because the phased array radar offers the advantages of power management and efficiency, reliability, signal reception, beam steering target detection. The current phased array radar designs are very large, complex and expensive and less efficient because of high RF losses in the phase control circuits used for beam scan. Several thousands of phase shifters and drivers may be required for a single system thus making the system very complex and expensive. This paper describes the phased array radar system based on high power T/R modules, wide-band radiating planar antenna elements and very low loss wide-band phase control circuits (requiring reduced power levels) for beam scan. The phase shifter design is based on micro-strip feed lines perturbed by the proximity of voltage controlled piezoelectric transducer (PET). Measured results have shown an added insertion loss of less than 1 dB for a phase shift of 450 degrees from 2 to 20 GHz. The new wideband phased array radar design provides significant reduction in size cost and weight. Compared to the conventional phased array systems, the cost saving is more than 15 to 1.

Modified thermal sensors have been produced and characterized for fingerprint recording applications. The sensors are derived from the IR imaging technology developed at INO. The sensor array is made of 160x120 pixel VO_x based micro thermistors that provide an image of a surface area of 8.3 x 6.2 mm² with a resolution of 488 dpi. The sensors were reinforced to withstand the mechanical pressure of the finger and the electrical discharges from the human skin. It is shown that despite their low thermal insulation, the sensors provide an image of the fingerprint pattern with relatively high contrast and resolution. With the acquisition electronics of an IR imager, the temprature of the sensor must be controlled. Measurements of the thermistor temperature were performed in order to access the intrinsic properties of the fingerprint sensors. The NETD is on the order of 2 10^-3°C when the pass band of the filter is 330 kHz. The temporal behavior of the thermistor temperature shows that 10 ms after the finger has been brought into contact, with the sensor, the temperature difference between thermistors in ridge and valley areas of the fingerprint DT_r,v may reach 80 10^-3°C, for an initial temperature difference between the finger and the sensor of 1°C. Once the sensor reaches a steady thermal state after a long time, the same difference decreases to 1.9 10^-3°C. The required temperature difference DT_r,v, estimated to be 4.8 10^-3°C to achieve an adequate signal to noise ratio, is relatively easy to reach at short and at long time periods. A modification to the method of acquisition is proposed to cancel the effect of the thermal drift of the sensor and to eliminate the need for the sensor temperature stabilization with a TEC. With this method, the recording of the fingerprint pattern may be achieved in 50 ms after the finger has been brought into contact. This leads to interesting gains in space, time and power consumption. Finally, for applications where the finger must remain in contact with the sensor, the same method may be efficient to reduce the need for thermal control.

Video systems are the backbone of most modern security systems. They help security personnel detect and recognize people who don’t belong in specific areas and who warrant suspicion. Low cost, low power uncooled thermal imaging sensors have completely changed the way the world views the video systems used in security, surveillance and law enforcement. Thermal Imaging (TI) is the only completely passive, all-weather, 24-hr surveillance tool that allows security personnel to take back the night, something they couldn’t do with inferior techniques of surveillance. This paper addresses advances in IR senosrs for law enforcement and security. It also addresses the bigger picture of using these sensors in the ever evolving and improving law enforcement and security surveillance system.

A 16x16 element un-cooled pyroelectric detector array has been developed which, when allied with advanced tracking and detection algorithms, has created a universal detector with multiple applications. Low-cost manufacturing techniques are used to fabricate a hybrid detector, intended for economic use in commercial markets. The detector has found extensive application in accurate people counting, detection, tracking, secure area protection, directional sensing and area violation; topics which are all pertinent to the provision of Homeland Security. The detection and tracking algorithms have, when allied with interpolation techniques, allowed a performance much higher than might be expected from a 16x16 array. This paper reviews the technology, with particular attention to the array structure, algorithms and interpolation techniques and outlines its application in a number of challenging market areas. Viewed from above, moving people are seen as 'hot blobs' moving through the field of view of the detector; background clutter or stationary objects are not seen and the detector works irrespective of lighting or environmental conditions. Advanced algorithms detect the people and extract size, shape, direction and velocity vectors allowing the number of people to be detected and their trajectories of motion to be tracked. Provision of virtual lines in the scene allows bi-directional counting of people flowing in and out of an entrance or area. Definition of a virtual closed area in the scene allows counting of the presence of stationary people within a defined area. Definition of 'counting lines' allows the counting of people, the ability to augment access control devices by confirming a 'one swipe one entry' judgement and analysis of the flow and destination of moving people. For example, passing the 'wrong way' up a denied passageway can be detected. Counting stationary people within a 'defined area' allows the behaviour and size of groups of stationary people to be analysed and counted, an alarm condition can also be generated when people stray into such areas.

MicroIR uncooled infrared imaging modules (based on VO_x microbolometers), developed and manufactured at BAE SYSTEMS, are integrated into ruggedized, weatherproof camera systems and are currently supporting numerous security and surveillance applications. The introduction of uncooled thermal imaging has permitted the expansion of traditional surveillance and security perimeters. MicroIR cameras go beyond the imagery limits of visible and low-light short wavelength infrared sensors, providing continual, uninterrupted, high quality imagery both day and night. Coupled with an appropriate lens assembly, MicroIR cameras offer exemplary imagery performance that lends itself to a more comprehensive level of surveillance. With the current increased emphasis on security and surveillance, MicroIR Cameras are evolving as an unquestionably beneficial instrument in the security and surveillance arenas. This paper will elaborate on the attributes of the cameras, and discuss the development and the deployment, both present and future, of BAE SYSTEMS MicroIR Cameras.

The Law Enforcement technology development community has a growing interest in the technologies associated with gunshot detection and localization. These interests revolve around community-oriented policing. Technologies of interest include those associated with muzzle blast and bullet shockwave detection and the inter-netting of these acoustic sensors with electro-optic sensors. To date, no one sensor technology has proven totally effective for a complete solution. PSI has a muzzle blast detection and localization product which is wireless, highly mobile and reconfigurable, with a user-friendly laptop processor and display unit, which completed a one-year demonstration in Austin, Texas on July 6, 2002. This demonstration was conducted under a Cooperative Agreement with the National Institute of Justice and in cooperation with the Austin Police Department. This paper will discuss the details of the demonstrations, provide a summarized evaluation, elucidate the lessons learned, make recommendations for future deployments and discuss the developmental directions indicated for the future.

Small arms' fire generates two distinct impulsive sounds: the shock wave created by the supersonic bullet and the muzzle blast produced at the weapon by the rapid discharge of the propellant after ignition. At short ranges, the directions of arrival and the times of arrival of these two sounds provide enough information to estimate accurately the distance to the shooter. At longer ranges, the ballistic of the bullet comes into play and the shock wave parameters are used to solve the problem. The maximum pressure of the shock wave and its period is an additional piece of information that allows the estimation of both the miss distance and calibre of the bullet. Ferret is an acoustic system designed to detect and recongnize the shock wave and muzzle blast of small arms' fire. The system comprises a small array of microphones and pressure sensors connected to a standard PC-104 computer that analyses, displays, reports and logs the parameters of a recognized shot. This project is the result of seven years of a collaborative effort between Defence R&D Canada and MacDonald Dettwiler and Associates.

In this paper, a re-programmable receiver architecture, based on software-defined-radio concept, for wireless signal interception is presented. The radio-frequency (RF) signal that the receiver would like to intercept may come from a terrestrial cellular network or communication satellites, which their carrier frequency are in the range from 800 MHz (civilian mobile) to 15 GHz (Ku band). To intercept signals from such a wide range of frequency in these variant communication systems, the traditional way is to deploy multiple receivers to scan and detect the desired signal. This traditional approach is obviously unattractive due to the cost, efficiency, and accuracy. Instead, we propose a universal receiver, which is software-driven and re-configurable, to intercept signals of interest. The software-defined-radio based receiver first intercepts RF energy of wide spectrum (25MHz) through antenna, performs zero-IF down conversion (homodyne architecture) to baseband, and digital channelizes the baseband signal. The channelization module is a bank of high performance digital filters. The bandwidth of the filter bank is programmable according to the wireless communication protocol under watch. In the baseband processing, high-performance digital signal processors carry out the detection process and microprocessors handle the communication protocols. The baseband processing is also re-configurable for different wireless standards and protocol. The advantages of the software-defined-radio architecture over traditional RF receiver make it a favorable technology for the communication signal interception and surveillance.

We study the problem of computing with encrypted data. We propose a hiding scheme that allows a client to execute a simple loop program with real or complex inputs securely on a server. This is the first hiding scheme that we are aware of that applies to real and complex data. The scheme allows the client to efficiently determine with high probability whether the results returned by the server are correct. The scheme we propose uses new techniques that have not been used previously in this context.

In response to a pressing demand for tagging systems and technologies developing, Physical Optics Corporation (POC) proposes a novel Passive Optoelectronical (POET) Tag system. The POET tag is an omnidirectional (360° in azimuth), with up to 180° field-of-view in elevation, retroreflection optical system with a high frequency multiple quantum well (MQW) light intensity modulator for free space IR optical communication. The POET tag optical scheme is a compact, high quality generalized fish-eye lens with telecentric arrangement in image space. The telecentric arrangement in image space provides perfect omnidirectional retroreflection of a recall beam and an optimum divergent of light at the MQW providing maximum modulation contrast ratios. The important POET tag features are low power consumption, zero probability of jamming and intercepting (high security of communication,) because it operates in a passive retroreflection mode with a highly-directed optical beam.

Visible, infrared (IR) and sensor-fused imagery of scenes that contain occluded camouflaged threats are compared on a two dimensional (2D) display and a three dimensional (3D) display. A 3D display is compared alongside a 2D monitor for hit and miss differences in the probability of detection of objects. Response times are also measured. Image fusion is achieved using a Gaussian Laplacian pyramidal approach with wavelets for edge enhancement. Detecting potential threats that are camouflaged or difficult to see is important not only for military acquisition problems but, also for crowd surveillance as well as tactical use such as on border patrols. Imaging and display technologies that take advantage of 3D and sensor fusion will be discussed.

We propose a novel enhanced wireless hypercompressed video surveillance system for advanced warning of such threats as asymmetric threats from terrorist attacks. A novel video interface card (VIC) technology is proposed for transmitting spatial and temporal events with very low GSM (9.6kbps) bandwidth, in spite of high original VGA-video bandwidth (221 Mbps).

With rapid technological developments, a new innovative range of possibilities can be actualized in mainstreaming a network with checks and balances to provide sensor and tracking data integration/information to a wider Department of Defense (DoD) audience or group of agencies. As technologies are developed, methods to display the data are required. Multiple diverse tracking devices and sensors need to be displayed on a common operating picture. Sensors and tracking devices are used to monitor an area or object for movement or boundary penetration. Tracking devices in turn determine transit patterns of humans, animals and/or vehicles. In consortium these devices can have dual applications for military requirements and for other general purposes. The DoD Counterdrug Technology Development Program Office (CDTDPO) has designed a system to distribute sensor and tracking data to multiple users in separate agencies. This information can be displayed in whole or in part as to the specific needs of the user. It is with this purpose that the Data Distribution Network (DDN) was created to disseminate information to a collective group or to a select audience.

Robust automatic detection and tracking of small targets in cluttered environments is becoming increasingly important; this is especially true in the surveillance of areas of high strategic importance. This paper describes an unattended electro-optical tracking system, designed to automatically detect and track moving targets in cluttered environments. Such a system has to have a low false alarm rate whilst maintaining a high probability of detection. Once a target has been detected a security alert can be issued and the security personnel are automatically shown the relevant images and a risk factor can be applied to each target. Often surveillance systems will be positioned such that there will be sources of false alarms within view. Rejection of these sources is critical, however rejection of genuine targets close to them should be avoided. Methods of rejecting clutter are investigated, these include rejection of known features e.g. vegetation, and rejection of targets that conform to expected patterns e.g. vehicles on a road. Further to this, target tracks are maintained in a 'local' Cartesian coordinate set allowing the possibility of pin-pointing the target and maintaining a track whilst scan capability.

On September 11, 2001, Al Qaeda terrorists committed a savage act against humanity when they used domestic jetliners to crash into buildings in New York City and Washington, DC, killing thousands of people. In October 2001, coming on the heels of this savagery was another act of barbarity, this time using anthrax, not jetliners, to take innocent lives. Each incident demonstrates the vulnerability of an open society, and Americans are left to wonder how such acts can be prevented. Now, Al Qaeda operatives are reportedly regrouping, recruiting, and changing their tactics to distribute money and messages to operatives around the world. Many experts believe that terrorist attacks are inevitable. No city is immune from attack, and no city is fully prepared to handle the residual impact of a potentially ravaging biological or chemical attack. A survey conducted by the Cable News Network (CNN) in January 2002, studied 30 major US cities, ranking them based on 6 statistical indices of vulnerability. Thirteen cities were deemed better prepared than Houston, 10 were in a similar state of preparedness, and only 6 were less prepared than Houston. Here, we discuss the measures which have taken place in Houston to make it a safer place and which plans are needed for future. Houston experience can be used as a model to develop similar plans for other cities nation-wide.

The Avalanche Photodiode (APD) is a unique device that combines the advantages of solid state photodetectors with those of high gain devices such as photomultiplier tubes (PMTs). APDs have internal gain that provides a high signal-to-noise ratio. APDs have high quantum efficiency, are fast, compact, and rugged. These properties make them suitable detectors for important applications such as LADAR, detection and identification toxic chemicals and bio-warfare agents, LIDAR fluorescence detection, stand-off laser induced breakdown spectroscopy (LIBS), and nuclear detectors and imagers. Recently there have been significant technical breakthroughs in fabricating very large APDs, APD arrays, and position sensitive APD arrays (PSAPD). Signal gain of over 10,000 has been achieved, single element APDs have been fabricated with active area greater than 40 cm², monolithic pixelated arrays with up to 28 x 28 elements have been fabricated, and position sensitive APDs have been developed and tested. Additionally, significant progress has been made in improving the fabrication process to provide better uniformity and high yield, permitting cost effective manufacturing of APDs for reduced cost.