Showing papers in "Johns Hopkins Apl Technical Digest in 2008"

Harsh environments : space radiation environment, effects, and mitigation

Abstract: Radiation effects in solid-state microelectronics can be split into two general categories: cumulative effects and single-event effects (SEEs). Cumulative effects produce gradual changes in the operational parameters of the devices, whereas SEEs cause abrupt changes or transient behavior in circuits. The space radiation environment provides a multitude of trapped, solar, and cosmic ray charged particles that cause such effects, interfere with space-system operation, and, in some cases, threaten the survival of such space systems. This article will describe these effects and how their impact may be mitigated in silicon-based microcircuits.

Public Health Surveillance for Mass Gatherings

Abstract: ass gatherings represent specific challenges for public health officials because of the health risks associated with crowd size and duration of stay. In addition, population movement requires public health departments to interact across jurisdictional boundaries to identify risks and disease-management solutions. However, federal privacy laws restrict the sharing of patient data among public health departments in multiple jurisdictions. This article examines previous disease surveillance practices by public health officials in planning for mass events and describes a simple approach for sharing health-risk information that was employed in 2007 during Super Bowl XLI by the health departments of Indiana, Marion County, Cook County, and Miami-Dade County.

Polymer adhesives and encapsulants for microelectronic applications

Abstract: This article provides an overview of the use of polymer adhesives in microelectronic packaging, with key applications including die attachment, underfills, and encapsulants. For many applications, polymer adhesives provide several advantages over alternative materials, and polymers have been widely used for die attachment. In flip-chip devices, polymers are being used for electrical interconnects instead of metallurgical joints. Polymer encapsulants are widely used to package microelectronic and optoelectronic devices when hermeticity is not required. The various types of materials and their properties are presented along with the relative advantages and disadvantages. Processing and assembly steps, testing, and reliability issues also are discussed.

Drinking Water Security and Public Health Disease Outbreak Surveillance

Abstract: The U.S. Environmental Protection Agency (EPA) strives to develop technologies and protocols to assist drinking water utilities in reducing the risks of potential terrorist attacks on our nation's infrastructure. Of particular interest are the development and feasibility testing of contamination warning systems that integrate existing public health surveillance and water quality measurements. In collaboration with the EPA, APL is developing a novel prototype warning system that employs sensor clustering and Bayesian Network analyses. These techniques address the challenges of synthesizing results from disparate data types with different data rates and complex environmental and operational responses into a warning system that can provide the user with a measure of the likelihood that data anomalies do or do not indicate a potential water-borne disease outbreak These critical challenges and how this novel approach and its components address them will be described.

Developments in the roles, features, and evaluation of alerting algorithms for disease outbreak monitoring

Abstract: utomated systems for public health surveillance have evolved over the past several years as national and local institutions have been learning the most effective ways to share and apply population health information for outbreak investigation and tracking. The changes have included developments in algorithmic alerting methodology. This article presents research efforts at The Johns Hopkins University Applied Physics Laboratory for advancing this methodology. The analytic methods presented cover outcome variable selection, background estimation, determination of anomalies for alerting, and practical evaluation of detection performance. The methods and measures are adapted from information theory, signal processing, financial forecasting, and radar engineering for effective use in the biosurveillance data environment. Examples are restricted to univariate algorithms for daily time series of syndromic data, with discussion of future generalization and enhancement.

The Pandemic Influenza Policy Model, a Planning Tool for Military Public Health Officials

Abstract: The Pandemic Influenza Policy Model (PIPM) is a collaborative computer modeling effort between the Department of Defense (DoD) and APL. Many helpful computer simulations exist for examining the propagation of pandemic influenza in civilian populations. We believe the mission-oriented nature and structured social composition of military installations may result in pandemic influenza intervention strategies that differ from those recommended for civilian populations. In addition, intervention strategies may differ between military bases because of differences in mission, location, or composition of the population at risk. The PIPM is a web-accessible, user-configurable, installation-specific, quick-response disease model allowing military planners to evaluate various intervention strategies. Innovations in the PIPM include expanding on the mathematics of prior stochastic models by using social network epidemiology, a user-friendly graphical user interface, utilization of DoD personnel databases to more accurately characterize the population at risk and the incorporation of possible interventions, e.g., pneumococcal vaccine, not examined in previous models.

The Potential Utility of Electronic Disease Surveillance Systems in Resource-PoorSettings

Abstract: With the concern over emerging infectious diseases, such as avian influenza, and the inception of the recently modified World Health Organization's (WHO) International Health Regulations, there is a clear need for enhanced disease surveillance throughout the world but especially in resource-poor settings. To date, most electronic disease surveillance systems have been implemented in industrialized countries where there is greater accessibility to technology infrastructure and electronic data. However, although systems deployed in developing settings vary in sophistication, they still can succeed in establishing an early detection capability where one does not currently exist. Based on the systems research and implementation experience of APL and the international surveillance experience of the U.S. Department of Defense Global Emerging Infections Surveillance and Response System (DoD-GEIS), we have drafted a framework for consideration by system implementers as many member states try to come into compliance with the new WHO regulations.

A method for generation and distribution of synthetic medical record data for evaluation of disease-monitoring systems

Abstract: There are several initiatives within the health care community to exchange patient medical records across health care facilities. These records hold the potential of providing public health officials with the ability to identify and monitor diseases posing a health risk to their communities. Tools are needed to exploit the wealth of data and information contained within these records. Synthetic medical record data are needed for development and evaluation of new techniques. A hybrid of real background disease levels with injected cases of disease has shown utility for testing systems. The generation of medical records in response to patient chief complaints is provided by the addition of a care delivery model. Once the model is fully developed, synthetic medical record data can be provided as a service, on the National Health Information Network, for developers and public health agencies to support evaluation and training.

Tradeoffs driving policy and research decisions in biosurveillance

Abstract: n view of concerns over bioterrorism, pandemic influenza, and other public health threats, development of advanced surveillance systems to corroborate and supplement physician sentinel surveillance is a research imperative. Objectives of this article are to describe interrelated decisions underlying the design of a public health surveillance system and to show these decisions’ effects on data acquisition and transfer, on analysis methods, and on visualization tools. Some of these decisions are dictated by data limitations, others by goals and resources of the monitoring organization. Most such decisions involve three characteristic tradeoffs: the extent of monitoring for exceptional versus customary health threats, the level of data aggregation for monitoring, and the degree of automation to be used. A fundamental motivation is to extract outbreak information from background noise to empower epidemiologists monitoring public health on a day-to-day basis. This article discusses each of these tradeoffs and illustrates them with three detailed examples.

Decision Support Models for Public Health Informatics

Abstract: With an increasing concern over emerging infectious diseases, efficient and reliable public health monitoring is critical. The prototype models described in this article were built to aid public health officials in monitoring the health of their communities by increasing situational awareness and reducing false-positive identification of disease outbreaks. This comprehensive capability is needed to bolster public health acceptance of biosurveillance systems by making the complex information environment more manageable and by achieving performance that is more robust. The models introduced in this article were built to recognize and differentiate influenza outbreaks from the other seasonal respiratory activities. The models were tested with historical data collected by the Electronic Surveillance System for the Early Notification of Community-based Epidemics (ESSENCE) in the National Capital Region. Results show significant improvement in both the sensitivity and specificity of the detections compared with the ESSENCE algorithms.

Microelectronic substrates for Optoelectronic packages

Abstract: Electronic systems with the increased functionality and speed required in today's advanced applications are placing a performance burden on the interconnection and packaging technologies that standard electrical "wiring" approaches simply cannot support. Engineering staff at APL recognized this trend several years ago, and in a collaborative effort with The Johns Hopkins University Department of Electrical and Computer Engineering, APL has been developing various microelectronic packages that support both electrical and optical signals and facilitate the translation between them. Work has begun to fabricate microelectronic substrates that use integrated optical waveguides to raise the level of the total system's performance as needed. This report will present some of the current technology for optoelectronic packages, an overview of the process technologies being developed industry-wide to meet the need, and details on related work within the Research and Technology Development Center and the Engineering, Design, and Fabrication Branch of the Technical Services Department here at APL.

Air Quality Effects on Health-Indicator Data in Disease Outbreak Surveillance

Abstract: Utilizing the concept that air quality has predictable impacts on certain disease patterns enables better detection of unexpected fluctuations in community health trends and thereby enhances earlier detection of disease outbreaks. This study illustrates that increases in daily outdoor ozone concentrations are associated with quantifiable short-term increases in hospital emergency department visits for asthma exacerbations among Medicaid patients, especially among 5-12 year olds. Spatial variation in asthma visits did not appear to be completely explained by spatial variations either in pollutant level or in Medicaid population. Recognizing air quality impacts in health data will enable disease surveillance systems to rule out relatively common air quality problems in monitoring for the effects of a bioterrorist attack Routine monitoring of air quality indicators along with the corresponding health-indicator effects also can assist in establishing expected ranges for disease levels to establish alerting thresholds for disease outbreak surveillance.

Methods for Information Sharing to Support Health Monitoring

Abstract: The practice of real-time surveillance of disease categories, sometimes called syndromic surveillance, is widespread at local, state, and national levels.The diseases identified by these systems, however, ignore health department jurisdictional boundaries. This creates situations where it is important for public health officials to be aware of conditions in other jurisdictions. There are currently two fundamental ways for systems to accomplish this: (\) share the underlying data or (ii) share information produced by the systems or their users. While many other efforts have concentrated on sharing data, the JHU/APL Center of Excellence in Public Health Informatics has been working on technology that allows information (rather than data) to be shared between multiple public health jurisdictions.

Technology advances and globalization in electronic and electro-optical packaging

Abstract: Semiconductor technology and integrated optical device technology, coupled with modern, miniaturized packaging, form the backbone of today's high-performance electronic and electro-optical systems. This article explores some current and future electronic and electro-optical device technologies and their impacts on APL. It also explores the ramifications and impact ofglobalization on the accessibility of this technology to APL. In a similar vein, the article describes the latest trends in packaging and how packaging is essential to the development of high-performance systems. Packaging has been fully globalized for many years, and thus the question is not when globalization will occur but rather how to best exploit the global packaging technology and keep critical access forAPL. The packaging discussion also focuses on important APL advances in optical waveguides and transitions as well as on advanced flexible-integrated-circuit assemblies.

Enhancing Public health Disease Surveillance Capability : Exercising the National Capital Region Syndromic Surveillance Network

Abstract: ver the past decade, local, state, and national public health agencies in the United States have, to varying degrees, started using electronic disease surveillance systems. Some systems rely on traditional reporting mechanisms, but others use automatically generated electronic clinical and nonclinical health-indicator data to discern unusual disease patterns in the community. In many instances, such systems have provided valuable adjunct surveillance opportunities and established collaborations between public health practice and other public and private agencies. This article describes four simulated tabletop exercises of varying complexity conducted by using the National Capital Region Syndromic Surveillance Network. These exercises served as a tool for the public health agencies to test system capabilities and their own surveillance capacities under simulated health events, and they fostered vital interjurisdictional collaborations. The information gleaned from these exercises played a vital part in the continued refinement of the Electronic Surveillance System for the Early Notification of Community-based Epidemics (ESSENCE).

Semiconductor devices : Moore marches on

Abstract: he tremendous growth in semiconductor technology has been based on the well-behaved Si−SiO 2 system. In 1965, Gordon Moore, cofounder of Intel and arguably APL’s most famous alumnus, saw the future. His prediction, now popularly known as Moore’s Law, states that the number of transistors on a chip doubles approximately every 2 years. Up until now this “law” has been followed by evolutionary progress of the basic technology. This progress has reached its limit. Major material modifications to the gate and drain regions of active devices will allow improvements in Si-based components to continue until 2020, but completely new concepts and technologies will be required to allow Moore’s Law to hold after that. These technologies include graphene and carbon nanotube-based devices, single-electron transistors, spintronics, and quantum computing. None of these are at a technology readiness level to take over, although spintronics has a good start because it already forms the basis of multi-billion dollar industries in magnetic read heads and magnetic random access memories.

Reliable miniature electronic and optical interconnects for low-volume applications

Abstract: At some level, all integrated circuit devices, passive devices, and optoelectronic devices must be interconnected together to function as a highly integrated electronic or optoelectronic system. As silicon-based device technologies have continued to evolve, the number of chip-level and package-level interconnections has increased dramatically while chip sizes have remained relatively constant. This dramatic increase in interconnection density has been enabled through the adoption of area array packages such as ball grid arrays and chip-scale packages.To accommodate these area array packages, today's printed wiring board fabrication techniques are featuring 1 00-μm (2-mil) lines and spaces as well as 0.25-mm-diameter (10-mil) blind and buried vias, both of which are necessary for high interconnection densities. Although the technology for wiring chips to packages and packages to boards for high-volume applications is relatively mature, it becomes increasingly ambitious to implement that technology for low-volume electronic applications. The nature ofAPL's wide range of innovative, miniature electronic development activities necessitates the use of high-density interconnection methods. This article focuses on APL's ongoing activity to develop high-density interconnection methods for use with low-volume, noncommercial electronic applications.

The Johns Hopkins University Applied Physics Laboratory Center of Excellence in Public Health Informatics

Abstract: For the post 10 years, APL has been supporting the public health disease surveillance mission by developing and implementing automated applications to acquire, process, and present data using modern information technology. The effort grew from a modest independent research and development activity to APL's receiving an award as one of the National Centers for Disease Control and Prevention's Centers of Excellence in Public Health Informatics.This issue presents some of the recent work being performed within the Center. This article provides an introduction to disease surveillance and the work within the JHU/APL Center of Excellence in Public Health Informatics.