Keystone Project Research Articles

The K2 Asteroseismic KEYSTONE sample of Dwarf and Subgiant Solar-Like Oscillators

Aims. The KEYSTONE project aims to enhance our understanding of solar-like oscillators by delivering a catalogue of global asteroseismic parameters (Δv and vmax) for 173 stars, comprising mainly dwarfs and subgiants, observed by the K2 mission in its short-cadence mode during campaigns 6–19. Methods. We derive atmospheric parameters and luminosities using spectroscopic data from TRES, astrometric data from Gaia, and the infrared flux method (IRFM) for a comprehensive stellar characterisation. Asteroseismic parameters are robustly extracted using three independent methods, complemented by an iterative refinement of the spectroscopic analyses using seismic log g values to enhance parameter accuracy. Results. Our analysis identifies new detections of solar-like oscillations in 159 stars, providing an important complement to already published results from previous campaigns. The catalogue provides homogeneously derived atmospheric parameters and luminosities for the majority of the sample. Comparison between spectroscopic Teff and those obtained from the IRFM demonstrates excellent agreement. The iterative approach to spectroscopic analysis significantly enhances the accuracy of the stellar properties derived.

Social interaction and gamification with youth at risk of social exclusion: The technological approach of the Keystone project

This paper presents the Keystone project, which proposes a multidisciplinary approach to improve the opportunities of young people at risk of social exclusion. The focus of the paper is the technological approach built from the results of research using lifeworld analysis to identify the barriers and drivers to youth participation. This technological approach combines on the one hand, the KEY Tool, a simplified goal-oriented social network to share and interact with local and international peers; on the other hand, the KEY game, a false instant-messaging application based on a voodoo story, where the user has a key role. Several pilot groups worked under the programme implemented in the Keystone project, including working with those digital tools. Results show important benefits for participating young people in areas such as respect, digital literacy and multi-cultural abilities, and highlight several opportunities to take further advantage of these tools.

Information entropy in cosmological inference problems

ABSTRACT The subject of this paper is a quantification of the information content of cosmological probes of the large-scale structures, specifically of temperature and polarization anisotropies in the cosmic microwave background (CMB), CMB-lensing, weak cosmic shear and galaxy clustering, in terms of information theory measures like entropies. We aim to establish relationships between conventional measures of statistical uncertainties and information entropies for Gaussian likelihoods, which are described by the Fisher-formalism. Furthermore, we extend these studies to the computation of (Bayesian) evidences and the power of measurement to distinguish between competing models. We investigate in detail how cosmological data decrease information entropy by reducing statistical errors and by breaking degeneracies. In addition, we work out how tensions between data sets increase information entropy and quantify this effect in three examples: the discrepancy in Ωm and σ8 between the CMB and weak lensing, the role of intrinsic alignments in weak lensing data when attempting the dark energy equation of state parameters, and the famous H0-tension between Cepheids in the Hubble keystone project and the CMB as observed by Planck.

Sustaining Reductions in Central Line–Associated Bloodstream Infections in Michigan Intensive Care Units

This article describes the interventions that sustained low central line-associated bloodstream infection (CLABSI) rates in the Michigan Keystone ICU Project. This analysis included data from March 2004 to December 2013 for 121 intensive care units (ICUs) in 73 hospitals. The Keystone Project was a cohort collaborative with an improvement team in each ICU. During the sustainability period, teams integrated the intervention into staff orientation, collected and submitted monthly data, and reported infection rates to leaders. The annual mean rate of BSIs dropped from 2.5 infections/1000 catheter-days in 2004 to 0.76 in 2013. A subset analysis found nearly double the percentage of ICUs with a mean rate of <1 infection/1000 catheter-days in 2013 compared with baseline. Active involvement of hospital leaders and the Keystone Center as well as ongoing monitoring and feedback of performance were important in sustaining results. These findings suggest that large-scale improvement projects can be sustained, establishing a new normal for care.

Much Work Still to Be Done to Prevent Central Line–Associated Bloodstream Infections

Central Line Associated Bloodstream Infections (CLABSI) are all too common and often fatal events. To estimate the number of preventable CLABSIs, the authors analyzed SIR (Standardized Infection Ratio) and the number of CLABSI data from Hospital Compare. Several studies have suggested that an SIR of 0.35 may be achievable. If all institutions were able to perform at this level, then almost 50% of CLABSI would be prevented. Introduction: Central Line Associated Bloodstream Infections are all too common and often fatal events. Unfortunately using the latest available data, it can be argued that the medical industry has not done nearly enough to implement effective safety protocols and checklists designed to prevent these infections. A National Benchmark was set using CLABSI data gathered between 2006 and 2008 before prevention protocols were implemented in the vast majority of institutions. Using this data, the average performance was used to calculate Standardized Infection Ratio (SIR) and a National Benchmark was set which reflected average performance as a SIR of 1.0. Umscheild, et al. estimated in 2011 that as many as 65 to 70% of CLABSIs are preventable, which would define obtainable performance of facilities to have an SIR of between 0.30 to 0.35. Similar reductions were observed in the Keystone project. In a separate analysis, Saman, et al. used more recent CLABSI data and found the peak of the SIR distribution curve at 0.35 and advocated that this more accurately reflects the Obtainable SIR. Arguably, the current National Benchmark is an example of using old standards to define current performance. Methods: To estimate the number of preventable cases, a dataset was downloaded from Hospital Compare which was comprised of CLABSIs that occurred in Hospital ICUs during a data collection period of 7/1/2011 to 6/30/2012. To be included in the analysis a hospital had to have at least one predicted CLABSIs using the National Benchmark of 1.0. 1899 facilities were included in the analysis, 1135 had an SIR of greater than 0.35. The total number of Preventable Cases (PC) was then calculated from the number of Observed Cases (OC) in all facilities whose SIR was above that of the Obtainable SIR, using the following equation: PC = OC – [(Obtainable SIR/Facility’s SIR) * OC ] Three estimations of the obtainable SIR were used *Health Watch USA, Eastern Kentucky University, Essentia Institute of Rural Health, Corresponding Author: Kevin T Kavanagh, MD, MS Email: healthwatchusa@gmail.com Table 1: Estimation of the Number of Preventable Cases in Hospital ICUs out of the 10799 CLABSIs observed in ICUs between 7/1/2011 to 6/30/2012 Source of SIR SIR Preventable Cases National Benchmark Data – (2006 to 2008) 1.000 990 (9.2%) Average SIR 2011 Data (7/1/11 to 6/30/2012) 0.594 1128 (10.4%) Peak of the Curve SIR Data (1/1/11 to 12/1/2011) 0.350 5240 (48.5%) in this study. The first was the National Benchmark (SIR = 1.0), the average SIR of the Dataset (0.594) and the Obtainable SIR of 0.35. Results: The results shown in Table 1 revealed that almost 50% of the CLABSI could be prevented if facilities performed at the Obtainable SIR of 0.35. This represents 5240 patients and at a fatality rate up to 25%, or 1310 potential lives lost. Discussion: Wise, et al., estimated that in 2010 there were 15,000 CLABSIs in hospital ICUs, mainly at medium and large teaching hospitals. A targeted approach was suggested to achieve further reductions in central line infections. Our analysis also indicates that substantial improvement is still needed to prevent CLABSIs. In the 12 month period ending on June 30, 2012, there were 10799 CLABSIs in hospital ICUs that were reported to the National Healthcare Safety Network. It can be argued that almost half of these infections were preventable. Some in the healthcare industry have argued that this large variation is due to differences in reporting and definitions. However, this factor should be mitigated, since CLABSIs are now reported through the National Healthcare Safety Network, which has rigorous definitions and standards for how adverse events are reported. In addition, Saman, et al.(7) have shown that high SIRs for CLABSIs in Intensive Care Units are correlated with facility wide patient safety measures found on CMS’s Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) Survey, which may indicate problems in the culture of safety at the institution. In addition, over the last decade institutions have been treating and billing for these events, if there are existing problems with event diagnosis this would represent a significant failure of our healthcare system. The question which must be asked is can we do better and further improve our current results?

When Counting Central Line Infections Counts

Affiliations: 1. Department of Health Sciences, University of Leicester, Leicester, United Kingdom; 2. Center for Comprehensive Access and Delivery Research and Evaluation, Iowa City Veterans Affairs Health Care System, Iowa City, Iowa; and Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa. Received February 28, 2013; accepted March 3, 2013; electronically published April 18, 2013. 2013 by The Society for Healthcare Epidemiology of America. All rights reserved. 0899-823X/2013/3406-0002$15.00. DOI: 10.1086/670630 In this issue of the journal, Wise et al report encouraging news of significant declines in reported rates of central venous catheter (CVC) bloodstream infections (BSIs) in critical care units over the past 2 decades. Using data from the US Centers for Disease Control and Prevention’s (CDC’s) National Nosocomial Infections Surveillance system for the years 1990– 2004 and the National Healthcare Safety Network (NHSN) for the years 2006–2010, the authors carefully adjusted for changes in definitions, changes in hospital facility characteristics, and potential bias arising from the transition to the NHSN. They estimated that between 100,000 and 200,000 fewer infections have occurred compared with what might have been expected if infection rates had remained stable at 1990 levels. Much of the improvement can be attributed to increased utilization of evidence-based procedures for line insertion, along with such technical innovations as antimicrobial catheters and chlorhexidine insertion-site patches. More broadly, these declines are likely due to sweeping cultural change. The 2006 Michigan Keystone project in particular may be said to have disrupted the prevailing norm that hospital-acquired infections (HAIs) were simply the price of doing business in critical care. With its report of a reduction from a mean 7.7 to 1.4 central line BSIs per 1,000 catheter-days in more than 100 intensive care units (ICUs), the Keystone project demonstrated that many—though not all—central line infections are preventable. The findings of Wise and colleagues will be welcomed by patients, practitioners, and payers. But there is some room for caution, on 3 counts. The first relates to the appropriation of definitions intended for surveillance for purposes for which they were not originally designed. The second is linked and relates to the elasticity of notions of preventability. The third is that we may be reaching the limit of preventability, and we may have to confront the possibility that zero infections may not be an achievable goal in all circumstances. A small but important body of work points to considerable variability in how definitions of central line infections are applied and interpreted. One study, using 2004–2007 data from 20 ICUs at 4 large academic medical centers, found limited correlation between CVC BSI rates determined by infection preventionists and a computer algorithm–generated standard rate. A retrospective survey in 6 Australian hospitals found “unacceptably low” agreement between reported CVC BSIs and gold standard application of definitions. A recent ethnographic study of English ICUs points to some of the reasons why variability occurs in what gets counted as a CVC BSI: mundane challenges (setting up and operating data collection systems), clinical practices in dispatching samples for microbiological analysis, and differences in clinical judgement all play a part. Much of the variability has its roots in the CDC definitions themselves, which were designed for surveillance. Maximizing sensitivity—the detection rate—has traditionally been a goal of surveillance systems for HAIs because ensuring that all candidate infections are identified and that appropriate action is taken likely serves the best interests of patients. High specificity—indicating a low false-positive rate—is clearly a benefit too, mainly to avoid overtreatment and unwarranted costs. The CDC catheter-associated (not catheter-related) definition, used by many US hospitals, is known to maximize sensitivity and thus may overcount CVC BSIs. But recent policy developments, by appropriating HAI surveillance rates as a form of performance management, are changing the rules of the game. In October 2008, the US Centers for Medicare and Medicaid Services (CMS) eliminated additional payments for certain hospital-acquired conditions, including CVC BSI, and since January 2011 the CMS has required all hospitals participating in the Inpatient Prospective Payment System to report CVC BSI rates using the CDC’s NHSN. Currently, 32 states and the District of Columbia have policies requiring the reporting of CVC BSIs. Public report cards and rankings compiled by the media and advocacy groups now draw on

Decreasing Central-Line–Associated Bloodstream Infections in Connecticut Intensive Care Units

Central-line-associated bloodstream infections (CLABSIs) are a significant cause of preventable harm. A collaborative project involving a multifaceted intervention was used in the Michigan Keystone Project and associated with significant reductions in these infections. This intervention included the Comprehensive Unit-based Safety Program, a multifaceted approach to CLABSI prevention, and the monitoring and reporting of infections. The purpose of this study was to determine whether the multifaceted intervention from the Michigan Keystone program could be implemented in Connecticut and to evaluate the impact on CLABSI rates in intensive care units (ICUs). The primary outcome was the NHSN-defined rate of CLABSI. Seventeen ICUs, representing 14 hospitals and 104,695 catheter days were analyzed. The study period included up to four quarters (12 months) of baseline data and seven quarters (21 months) of postintervention data. The overall mean (median) CLABSI rate decreased from 1.8 (1.8) infections per 1,000 catheter days at baseline to 1.1 (0) at seven quarters postimplementation of the intervention. This study demonstrated that the multifaceted intervention used in the Keystone program could be successfully implemented in another state and was associated with a reduction in CLABSI rates in Connecticut. Moreover, even though the statewide baseline CLABSI rate in Connecticut was low, rates were reduced even further and well below national benchmarks.

Minimizing ambiguity to promote the translation of evidence-based practice guidelines to reduce health care-associated infections

A major challenge facing health care providers is the translation of evidence-based practice guidelines to the bedside.1-3 Despite the published success of the US-based Institute of Healthcare Improvement 100,000 Lives Campaign, the Keystone Project, and other patient safety initiatives endorsed by global organizations such as the World Health Organization, compliance with evidencebased health care-associated infection (HAIs) prevention guidelines varies considerably.4-7 Researchers have demonstrated that, in diverse clinical settings where emergent and routine care is administered, providers fail to standardize care processes that have been articulated and supported by recommended interventions.8-14 This variable compliance with recommendations has sparked considerable interest among human factors specialists. One such researcher, Ayse P. Gurses, PhD, et al conducted a qualitative study assessing compliance with evidence-based practice guidelines for the prevention of HAIs in intensive care units (ICUs).15 Dr Gurses et al also assisted with the development of a barrier identification and mitigation (BIM) tool to promote guideline compliance16 and has published an interdisciplinary conceptual framework to identify factors that affect clinicians’ compliance with evidence-based guidelines.17 Gurses et al suggest that consistent compliance with guidelines may be viewed as a system’s property of the clinical environment as well as a manifestation of individual care provider’s decisions and habits.15 Human factors research examines the clinical environment as a holisticwork system, evaluating both the physical layout of a unit as well as the unit’s embedded culture. The unit culture may support a particular work process because “that is how it has always been done,” rather than embracing evidence-based practice guidelines. One of the underlying tenets of human factors research is the belief that, to improve processes of care, it is necessary to begin looking at things differently and, in effect, question the status quo. Gurses et al performed in-depth interviews with 20 health care providers in 2 surgical ICUs to explore the underlying causes for noncompliance with evidence-based guidelines for the prevention

System-Level Quality Improvement Initiatives: Lessons from Keystone and Other Large-Scale Projects

Health care systems around the world are seeking system-level interventions to improve the quality and safety of care because of increasing awareness that many patients do not receive recommended therapies or suffer preventable complications. This has also been motivated by a drive to deliver health care more cost-effectively, and to be more accountable to payers and other stakeholders. The Keystone Project in Michigan is one example of a large-scale system-level initiative that successfully changed the "culture of safety" in the intensive care units of participating hospitals and led to improvements in both process outcomes and clinical outcomes. This article discusses factors that contributed to the success of the Keystone Project and also considers its economic implications. There are also recommendations for the design and evaluation of future system-level quality improvement programs.

Integrating CUSP and TRIP to Improve Patient Safety

Despite increased awareness of the risks to patients within the health care system, there has been little improvement in patient safety, with 1 in 7 patients experiencing an adverse event during hospitalization. Patients are exposed to harm not only through medical errors but also by physicians' failure to adhere to evidence-based best practices, as patients receive recommended therapies only half of the time. Although much research has been devoted to developing new therapies, little time has been spent investigating the science of health care delivery. We developed 2 models for improving health care delivery that have been successfully utilized in the Michigan Keystone Project to eliminate catheter-related bloodstream infections. The first is the Comprehensive Unit-Based Safety Program (CUSP), which is aimed at changing the culture of safety and provides a framework for addressing patient safety issues at a local level. CUSP takes advantage of local wisdom to identify potential patient harms and create individualized solutions. The second is the Translating Evidence Into Practice (TRIP) model, which evaluates best practices at a hospital or hospital system level, and then creates strategies for implementation at a local level. TRIP seeks to identify barriers to implementation of best-practice medicine and standardize care over multiple care units. Components of the 2 programs are not mutually exclusive and both can be used to mitigate potential patient harms.

Critical care checklists, the Keystone Project, and the Office for Human Research Protections: A case for streamlining the approval process in quality-improvement research

Critical care checklists, the Keystone Project, and the Office for Human Research Protections: A case for streamlining the approval process in quality-improvement research

Critical care checklists, the Keystone Project, and the Office for Human Research Protections: A case for streamlining the approval process in quality-improvement research

Critical care checklists, the Keystone Project, and the Office for Human Research Protections: A case for streamlining the approval process in quality-improvement research

Commentary:Centralized Assessment in Graduate Medical Education: How Can It Help Us Reinvent Training?

The article by Wagner and Lypson is thoughtprovoking at a number of levels for health care professionals. It is valuable not only to consider the immediate implications of assessing incoming residents’ preparedness for participation in clinical practice and learning, but to see how it may serve as a probe for a number of systemic issues in the education of health professionals. At first pass, the authors describe 2 remarkable efforts to improve the assessment and training of new postgraduate-year-1 (PGY-1) doctors. These efforts are notable for their involvement of expert clinical leadership in curriculum design, a clear focus on concepts and skills that may be inadequately addressed in traditional undergraduate education, and a process that is standardized yet has room for continuous iteration and improvement. The efforts clearly add substance and value to the residency programs involved, and also appear to give new residents a much clearer roadmap to their own optimal training. As such, this has much to recommend it for adaptation in any number of postgraduate education programs. This is also helped by the pragmatic focus on key steps and learnings for those who want to initiate a similar process. On another level, by creating an assessment process and data, the authors provide a valuable, if imperfect, lens into our training systems and the results they deliver. We all strive to train and support skilled physicians. Even those of us who have little contact with resident education are completely dependent on this process for our health care providers and leaders. As a physician in a large health maintenance organization, I have limited involvement with the process of graduate medical education, but work with 6 000 examples of the practicing physicians it produces–my colleagues in the medical group. How reliably are we preparing our next generation, and what can the current study add to our knowledge and understanding of opportunities for improvement and the steps we need to take? Opportunities for improvement will be made manifest by performance gaps. These gaps are identified consistently in a number of areas in the current work. In analyzing these, several assumptions can be made and are supported by the data. First, these results are real, and they identify issues that very likely translate into actual clinical care. Errors and failures to reliably deliver care are huge problems in our current health care delivery systems. 1 Second, these skills deficits are likely to add to cost and they may cause harm. Data from the Keystone project are one example. 2 In this study, basic skills and protocols for central line insertion were found to be lacking on a very broad scale, leading to harm and expense from bloodstream infections. These complications could be reduced significantly by focused performance improvement efforts. Surgical site infections are another example of considerable harm, with well-documented opportunities for improvement. 3–5 This adds urgency to finding and remediating these problems. It also opens the possibility of a far more robust system for tracking the benefit of these interventions that may assist with funding them. A system that can truly measure the cost of harm, optimize the reliability, and support the training of new physicians will be the model in the future. Third, we must be clear that the skills deficits measured are almost always a reflection on the educational system, not the quality of the entering resident. The PGY-1 physicians tested in this process are selected for high intelligence and work ethic; improving performance and competence is almost entirely a systemic reformation, not a winnowing of imperfect candidates.

Critical care checklists, the Keystone Project, and the Office for Human Research Protections: A case for streamlining the approval process in quality-improvement research*

Checklists have been recently promulgated as a method to enhance patient safety and improve outcomes for critically ill patients. Specifically, recent work performed by researchers from the Johns Hopkins Medical Institutions has demonstrated that the addition of checklists to usual care in the intensive care unit is associated with a decrease in the incidence of catheter-related bloodstream infections. Initially evaluated at the institutional level, this effort has been successfully expanded to the state level as part of the Michigan Keystone Project. Although this work has recently received significant positive attention in the lay press, the Office for Human Research Protections--as they felt that this was a research project requiring Institutional Review Board approval and informed consent--put the data collection on hold for lack of approval by the Institutional Review Board at the participating hospitals in Michigan as well as for not having obtained informed consent from each patient and clinician involved in the project. This article documents the recent events surrounding the Keystone Project and the response to the actions taken by the Office for Human Research Protections in the lay press and the new media (Internet and blogs), articulates how a determination can be made if a project is quality-improvement, human-subjects research, or both, and proposes some solutions to create a structured approach to this kind of research in the future.

Daily Goals Checklist—A Goal-Directed Method to Eliminate Nosocomial Infection in the Intensive Care Unit

Patients in the intensive care unit (ICU) are usually very sick and have complicated, multisystem dysfunctions and often life-threatening medical conditions. Their management requires skilled, comprehensive, and organized medical care. The use of the "ventilator bundle," "sepsis bundle;" and other evidence-based initiatives often results in improved quality of care and reduction of complications in the ICU. However, in reality, multiple factors can make the practitioners in the ICU overlook some of these quality measures. The daily goals checklist presented here is a quality tool that incorporates several evidence-based quality parameters, and it is easy to use and cost-effective. Its implementation is likely to greatly improve the quality of care and reduce complications in ICUs.

Fluxes of carbon dioxide at Thetford Forest

Abstract. The Thetford Project (1968–1976) was a keystone project for the newly established Institute of Hydrology. Its primary objective was to elucidate the processes underlying evaporation of transpired water and intercepted rainfall from plantation forest, so as to explain hydrological observations that more water was apparently returned to the atmosphere from plantations than from grassland and heathland. The primary approach was to determine the fluxes of water vapour from a stand of Scots pine, situated within a larger area of plantations of Scots and Corsican pine, in Thetford Forest, East Anglia, UK, using the Bowen ratio approach. In 1976, advantage was taken of the methodology developed to add measurement of profiles of carbon dioxide concentration so as to enable the fluxes of CO2 also to be calculated. A team from Aberdeen and Edinburgh Universities collected 914 hours of 8-point CO2 concentration profiles, largely between dawn and dusk, on days from March to October, and the data from an "elite" data set of 710 hours have been analysed. In conditions of moderate temperature (&lt;25°C) and specific humidity deficit (&lt;15 g kg−1 with high solar irradiance (&gt;500 W m−2), CO2 uptake reached relatively high rates for pine of up to 20 µmol m−2 s−1 in the middle of the day. This rate of CO2 uptake is higher than has been recently found for four Scots pine forests in continental Europe during July 1997. However, the year of 1976 was exceptionally hot and dry, with air temperatures reaching 30°C and the water deficit in the top 3 m of soil at the site of 152 mm by August. Air temperatures of over 25°C led to large specific humidity deficits, approaching 20 g kg−1, and associated severe reductions in CO2 uptake, as well as in evaporation. However, when specific humidity deficits dropped below c. 15 g kg−1 on succeeding days, generally as a result of lower air temperatures rather than lower solar irradiance, there was rapid recovery in both uptake and evaporation, thus indicating that the large soil water deficit was not the main cause of the reductions in the CO2 and water fluxes. Based on earlier analysis of evaporation data on completely dry days, the concurrent reductions in CO2 flux and evaporation are largely attributable to decrease in canopy stomatal conductance. The air temperature, specific humidity deficit, and soil water deficit in 1976 were exceptional and similar conditions have most likely not been experienced again until 2003. We conclude that the information gained at Thetford in 1976 on the response of the pine forest ecosystem to such weather, may provide a good guide to the response of English pine forests to the projected climate change over the next 25 years.

Differencing Reveals Hidden Changes in Baseline Length Time-series

In order to make successful earthquake predictions, detection and monitoring of baseline changes are important for investigating their origins, including precursory crustal deformations in tectonically active areas. In this study, differencing two baselines that run approximately parallel to each other and normal to the expected crustal deformations, and that share a station is proposed for analysis. Differencing reduces common systematic baseline errors, thereby enabling detection of subtle transient systematic changes in the baseline time-series that are otherwise buried in the measurement noise. Mean shift analysis, a well-known statistical technique to determine hether the mean of a stochastic process has shifted using cumulative sum charts, can then be used to locate the change points in the time-series. The application of this method to the differences of concurrently observed very long baseline interferometry (VLBI) and global positioning system (GPS) baselines in the Japanese Keystone project, where periodic and persistent baseline changes are removed, revealed transient variations in the baseline lengths several months prior to the seismic activity in the Izu Islands that started on June 26, 2000. Reproduction of the results using GPS and VLBI, two alternative baseline measurement techniques, validated the accuracy of the proposed approach for detecting previously hidden transient changes in the baseline lengths.

Microwave flux density variations of compact radio sources monitored by real‐time very long baseline interferometry

Compact and strong radio sources were repeatedly observed in regular geodetic very long baseline interferometry experiments under the Key Stone Project. The flux densities of these sources in the S and X bands were estimated from a set of correlated amplitudes obtained through the correlation processing of the observed data. From ∼5 years of the observed data, irregular variations in the flux densities were detected for several radio sources using the source 2134+004 as the calibrator. The results showed the monitoring of flux density variations by means of very long baseline interferometry is feasible. Since the correlation processing of the observed data are performed real‐time using a high‐speed digital communication technique, this method gives a capability to monitor flux density variations of quasars and BL‐Lac types of extragalactic radio sources.

Securing The Electronic Market: The KEYSTONE Public Key Infrastructure Architecture

In this paper, the unified, abstract KEYSTONE Public Key Infrastructure is presented. This architecture consists of a reference model, a functional architecture specification, and a set of technologies that can be used for implementing the functional units, along with all relevant standards. It was derived within the course of the KEYSTONE project, which was funded by the European Commission under the Electronic Trust Services II Programme. The proposed PKI architecture guarantees openness, scalability, flexibility, extensibility, integration with existing TTP and information infrastructure, transparency and, above all, security. Thus, it enjoys all the desirable characteristics and fulfils all those criteria that are essential for a PKI to constitute a successful framework for the development of inter-domain and international Trusted Services.

Real-time VLBI system using ATM network

The Communications Research Laboratory (CRL), Tokyo, Japan, and the Telecommunication Network Laboratory Group, Nippon Telegraph and Telephone Corp., Tokyo, Japan, have developed a highly precise, very long baseline interferometry (VLBI) system using a high speed asynchronous transfer mode (ATM) network. The observed data is transmitted through a 2.488-Gbps ATM network [STM-16/OC-48] instead of being recorded onto magnetic tape. The system was specially designed for the Key Stone Project (KSP), a project begun in 1994 to measure crustal deformation in the Tokyo metropolitan area. Cross-correlation processing and data observations are carried out simultaneously by one operator. It takes about one hour to analyze the data after the observations and correlations are completed. In regular geodetic VLBI experiments run every other day for 24 h, a horizontal position uncertainty of about 2 mm and a vertical position uncertainty of about 10 mm were achieved. The system was designed to enable automated operation throughout the entire process. The results obtained are available to the public via the Internet at http:ksp.crl.go.jp. This system is a significant advance in VLBI and should provide more precise information about crustal deformation in the Tokyo metropolitan area.