Large-scale Monitoring System Research Articles

Structural Basis for Ca2+-Dependent Formation of ALG-2/Alix Peptide Complex: Ca2+/EF3-Driven Arginine Switch Mechanism

ALG-2 belongs to the penta-EF-hand (PEF) protein family and interacts with various intracellular proteins, such as Alix and TSG101, that are involved in endosomal sorting and HIV budding. Through X-ray crystallography, we solved the structures of Ca(2+)-free and -bound forms of N-terminally truncated human ALG-2 (des3-20ALG-2), Zn(2+)-bound form of full-length ALG-2, and the structure of the complex between des3-23ALG-2 and the peptide corresponding to Alix799-814 in Zn(2+)-bound form. Binding of Ca(2+) to EF3 enables the side chain of Arg125, present in the loop connecting EF3 and EF4, to move enough to make a primary hydrophobic pocket accessible to the critical PPYP motif, which partially overlaps with the GPP motif for the binding of Cep55 (centrosome protein 55 kDa). Based on these results, together with the results of in vitro binding assay with mutant ALG-2 and Alix proteins, we propose a Ca(2+)/EF3-driven arginine switch mechanism for ALG-2 binding to Alix.

AN IMPORTANCE-AWARE ARCHITECTURE FOR LARGE-SCALE GRID INFORMATION SERVICES

This paper is concerned with the scalability of large-scale grid monitoring and information services, which are mainly used for the discovery of resources of interest. Large-scale grid monitoring systems have to balance between three competing performance metrics: query response time, imposed network overhead, and information freshness. Improving one of the three metrics will affect another; any solution will be based on a trade-off. The paper is motivated by the observation that existing grid monitoring systems can only be manually configured for a trade-off among the three metrics, which applies equally to all monitored resources; this implies that all resources in a grid are considered to be of equal importance. Assuming that in a large-scale grid setting this is unlikely to hold, the paper proposes an importance-based monitoring architecture for large-scale grid information services, based on an adaptation of the web crawling paradigm. The main idea is that, since not all resources are of equal importance, one can vary the trade-off based on the relative importance of the monitored resources. The proposed architecture is described and evaluated based on large-scale deployments of a prototype implementation on PlanetLab.

Co-designing the failure analysis and monitoring of large-scale systems

Large-scale distributed systems provide the backbone for numerous distributed applications and online services. These systems span over a multitude of computing nodes located at different geographical locations connected together via wide-area networks and overlays. A major concern with such systems is their susceptibility to failures leading to downtime of services and hence high monetary/business costs. In this paper, we argue that to understand failures in such a system, we need to co-design monitoring system with the failure analysis system. Unlike existing monitoring systems which are not designed specifically for failure analysis, we advocate a new way to design a monitoring system with the goal of uncovering causes of failures. Similarly the failure analysis techniques themselves need to go beyond simple statistical analysis of failure events in isolation to serve as an effective tool. Towards this end, we provide a discussion of some guiding principles for the co-design of monitoring and failure analysis systems for planetary scale systems.

Fault Detection for Large Scale Systems Using Dynamic Principal Components Analysis with Adaptation

The Dynamic Principal Component Analysis is an adequate tool for the monitoring of large scale systems based on the model of multivariate historical data under the assumption of stationarity, however, false alarms occur for non-stationary new observations during the monitoring phase. In order to reduce the false alarms rate, this paper extends the DPCA based monitoring for non-stationary data of linear dynamic systems, including an on-line means estimator to standardize new observations according to the estimated means. The effectiveness of the proposed methodology is evaluated for fault detection in a interconnected tanks system.

Development of an automated large-scale protein-crystallization and monitoring system for high-throughput protein-structure analyses

Protein crystallization remains one of the bottlenecks in crystallographic analysis of macromolecules. An automated large-scale protein-crystallization system named PXS has been developed consisting of the following subsystems, which proceed in parallel under unified control software: dispensing precipitants and protein solutions, sealing crystallization plates, carrying robot, incubators, observation system and image-storage server. A sitting-drop crystallization plate specialized for PXS has also been designed and developed. PXS can set up 7680 drops for vapour diffusion per hour, which includes time for replenishing supplies such as disposable tips and crystallization plates. Images of the crystallization drops are automatically recorded according to a preprogrammed schedule and can be viewed by users remotely using web-based browser software. A number of protein crystals were successfully produced and several protein structures could be determined directly from crystals grown by PXS. In other cases, X-ray quality crystals were obtained by further optimization by manual screening based on the conditions found by PXS.

FAULT DETECTION FOR LARGE SCALE SYSTEMS USING DYNAMIC PRINCIPAL COMPONENTS ANALYSIS WITH ADAPTATION

The Dynamic Principal Component Analysis is an adequate tool for the monitoring of large scale systems based on the model of multivariate historical data under the assumption of stationarity, however, false alarms occur for non-stationary new observations during the monitoring phase. In order to reduce the false alarms rate, this paper extends the DPCA based monitoring for non-stationary data of linear dynamic systems, including an on-line means estimator for the standardizing of the observations according to the estimated means. The effectiveness of the proposed methodology is evaluated for fault detection in a interconnected tanks system.

New Products

In this column, editors Eyal de Lara and Keith Farkas review initiatives that use cell phones as document scanners, as the basis for building large-scale environment monitoring systems, and to map physical objects to Web pages. They also review technology that lets you recover a document's original color from a grayscale version and a tool that automatically synchronizes files across multiple devices. Finally, we examine new additions to Nokia's Nseries of mobile phones, a compact GSM/General Packet Radio Service (GPRS) radio with a footprint of just 2.3 cm2, and a system that prevents digital cameras from recording still and moving images, which present an interesting approach to addressing the privacy concerns raised by ubiquitous systems.

Enhanced multiplexing capacity of low-coherence reflectometric sensors with a loop topology

A novel scheme for enhancing the multiplexing capacity of low-coherence reflectometric sensors is demonstrated. The scheme is based on connecting the sensing elements in serial in a loop configuration, allowing each of the sensors within the array being interrogated twice from opposite directions. The bi-directional interrogation enhances the multiplexing capacity in terms of maximum sensor number. The bi-interrogation scheme would also allow normal operation of the sensor array even when one end or somewhere of the transmission fiber were broken, improving the reliability of the sensing system for large-scale structural monitoring.

Information Monitoring on the Web: A Scalable Solution

This paper presents WebCQ, a continual query system for large-scale Web information monitoring. WebCQ is designed to discover and detect changes to Web pages efficiently, and to notify users of interesting changes with personalized messages. Users' Web page monitoring requests are modeled as continual queries on the Web and referred to as Web page sentinels. The system consists of five main components: a change detection robot that discovers and detects changes, a proxy cache service that reduces the communication traffics to the original information provider on the remote server, a trigger evaluation tool that can filter only the changes that match certain thresholds, a personalized change presentation tool that highlights Web page changes, and a change notification service that displays and delivers interesting changes and fresh information to the right users at the right time. This paper describes the WebCQ system with an emphasis on the general issues in designing and engineering a large-scale information change monitoring system on the Web. There are two main contributions. First, we present the mechanisms that WebCQ provides to support various types of Web page sentinels for finding and displaying interesting changes to Web pages. The large collection of sentinel types allows WebCQ to efficiently locate and monitor a wide range of changes in Web pages. The second contribution is the development of sentinel grouping techniques for efficient and scalable processing of large number of concurrently running triggers and Web page sentinels. We report our initial experimental results showing the effectiveness of the proposed solutions.

Intelligent Traffic Data Processing for ITS Applications

Real-time traffic data are the lifeline sustaining the operation of Advanced Traffic Management and Advanced Traveler Information Systems (ATMS/ATIS). Data are essential to drive algorithms related to congestion/incident detection, travel time forecasting, and real-time route guidance. A common problem in many ATMS/ATIS applications is the sparsity of real-time traffic data, reflecting the financial constraints of acquiring and maintaining large-scale traffic monitoring systems. This paper proposes the use of intelligent processing, or data integration tools, to overcome the data sparsity problem and make the best use of existing data resources. This approach recognizes the elements of uncertainty and vagueness in defining and solving the problem. An example application of the proposed data integration method is presented in the context of a congestion detection algorithm. The method uses an imprecise knowledge representation within the framework of fuzzy operator logic (FOL) and the modified Dempster-Shafer rule of combination. Results indicate that knowledge of a link congestion status (i.e., congested or uncongested) increased several folds after the data integration algorithm was applied. Further work is needed to calibrate the algorithm in the field (in this study simulation was used) and to apply the procedures on large-scale networks.

Influence of Heating Rate on the TL Response of LiF TLD-700, LiF:Mg,Cu,P and Al2O3:C

Influence of heating rate during thermoluminescence (TL) readouts on the response of the two relatively new TL dosemeters, Al 2 O 3 :C and LiF:Mg,Cu,P, has been compared with that of the widely used and established LiF TLD-700. Severe thermal quenching in Al 2 O 3 :C discs and a significant shift in the glow peaks of LiF:Mg,Cu,P sintered pellets to the temperature range where irreparable damage takes place, put limitations in the use of these materials in large scale monitoring systems having fast heating rates. The heating rate independence of TL response of dosimetric glow peaks of LiF TLD-700 has been confirmed for the most commonly encountered heating rates ranging from 1°C.s −1 to 50°C.s −1 . However, higher temperature glow peaks in LiF TLD-700, used in dosimetry of high LET radiations and mixed neutron-gamma fields, are found to exhibit a significant reduction in the response with increasing heating rates

Problems and priorities in epidemiologic research on human health effects related to wiring code and electric and magnetic fields.

Because of a reported excess of cancers among children living near power lines, there is some concern that electric and magnetic fields (EMFs) induced by electric power sources may affect human health, and this possibility has provoked considerable controversy. The scientific question of whether there are such health effects is far from resolved. Building upon a set of detailed reviews of the available evidence, this paper proposes research priorities and places particular emphasis on epidemiologic research. The most pressing need is to verify the validity of the claim that childhood cancer risk is affected by the type of wiring code in the vicinity of the household. More useful work can be done to verify this in the areas in which such studies have already been carried out, and additional studies should be done elsewhere. Methodological investigation of the interrelationships among different measures and proxies for EMF is needed, and this could feed back to influence the type of EMF measures used in epidemiologic studies. Studies of cancer among adults in relation to EMFs in the work place are needed. Of lower priority are studies of adverse reproductive outcomes in relation to parental EMF exposure and studies of the neurobehavioral impact of chronic EMF exposure. This article also discusses the structural impediments of conducting environmental epidemiology research and argues that bold, large-scale epidemiologic monitoring systems are needed. There is a discussion of the interface between epidemiology and public policy in a topic area as controversial as EMFs.

Evaluation of a soft-copy photogrammetry system for tree-plot measurements

This article describes and evaluates the application of a soft-copy photogrammetry system to large-scale forest inventories. A specially designed software, developed by the authors, has been investigated in terms of accuracy and general operability. Tests based on 1:1100 color aerial photographs, taken with a 10-m cross-boom system and digitized at resolutions of 300, 450, and 600 dots per inch, confirmed the expected tree-height accuracies of 48, 32, and 24 cm, respectively. This indicates that a photographic scale of 1:800 and a scanning resolution of 800 dots per inch could produce a tree-height precision of the order of 10 cm. The tests have shown that model orientation takes about 15 min; for a tree plot of 24 trees, measurements (height and crown diameter) and observations (species and condition) also take about 15 min. As the important problem of positioning a helicopter over a tree plot has now been solved using global positioning system receivers, the results and information presented in this paper indicate that the existing technology can provide a rigorous and operational photogrammetric system for large-scale forest inventories and regeneration monitoring.

Benchmark

Our bias is that the system should be sufficiently decentralized to meet the major needs of a variety of producers, yet have sufficient centralized planning and data sharing to allow the manipulation and analyses of the volume of data necessary to identify factors influencing health status and to assist in indentifying optimal health management strategies. Indeed the monitoring system and the health management program should be closely integrated. Continuous monitoring can also reveal the extent to which the objectives of health management have been reached. Certainly, the monitoring system should incorporate production data as well as data on disease. It is essential to quantify the effects of disease on production, and it is equally important to realize that the level of production (production efficiency if available) is often the best screening test for health status. In this paper we would like to portray systems that can serve the major needs of individual herd owners and veterinarians, and by data sharing can also meet the needs of provincial and federal governments for large scale monitoring systems.

Training clinical personnel to assess for tardive dyskinesia

1. 1. Two hundred and sixty-three people were trained to assess for tardive dyskinesia using the Dyskinesia Identification System:Condensed User Scale. 2. 2. A videotape pretest was given before training, a videotape posttest was given after training, and in vivo (actual patient) ratings were required.The data was analyzed for overall training effects as well as by four professional groups: registered nurses, licensed practical nurses, physicians/pharmacists, and others such as psychologists/educators. 3. 3. No group displayed accurate abnormal involuntary movement assessment ability before training, and a highly significant Improvement occurred as a result of training.The four professional groups did not differ on assessment ability before or after training, and all professions showed significant improvement. 4. 4. The data suggests that formal training must occur to teach accurate and reliable tardive dyskinesia assessment ability.A wide variety of professions can be trained, thus making large scale monitoring systems for applied clinical settings possible.

Resolution and variance in acoustic tomography

Acoustic tomography is a proposed system for large-scale remote monitoring of ocean variables, especially the sound speed, as functions of position. In such a system, a number of sources transmit pulse codes which are detected at a number of receivers, so that the volume spanned by sources and receivers is crossed by a large number of acoustic paths (including multipaths). Travel time perturbations from a known reference state must be inverted to obtain estimates of sound-speed fluctuations from that reference state. In this paper, the Backus–Gilbert method is used to study the resolution and variance of such estimates in a horizontal ocean slice. Data kernels which are singular along ray paths are ‘‘quelled’’ by integration. Estimates are interpreted as weighted local averages of the unknown function and the weighting functions, or resolution kernels, which characterize resolution at a particular point, are illustrated at representative points. Global representations of resolution are also formulated and plotted. It is shown how resolution can be compromised for the purpose of reducing the variance of estimates due to statistical error. Such trade-off relations are discussed and exemplified.