Online Computing Research Articles

Online computing of non-stationary distributions velocity fields by an accuracy controlled growing neural gas

This paper presents a vector quantization process that can be applied online to a stream of inputs. It enables to set up and maintain a dynamical representation of the current information in the stream as a topology preserving graph of prototypical values, as well as a velocity field. The algorithm relies on the formulation of the accuracy of the quantization process, that allows for both the updating of the number of prototypes according to the stream evolution and the stabilization of the representation from which velocities can be extracted. A video processing application is presented.

SVD-TLD Sensing Algorithm for EES-MIMO Radar

Based on Electromagnetic Environmental Sensory(EES)and Multiple-input Multiple-Out(MIMO) radar sensing algorithm , this paper presents SVD-TLD perception algorithm, which firstly use the cross-spectrum AR model parameter estimation, and secondly considering the cross-correlation matrix of the estimation error function disturbance and lastly taking into account of the two ends of the equation, using the cross-correlation function of the estimated measurement errors to affect the Total Least Squares (TLS) method . Compared with the AR model parameter estimation, the accuracy of SVD algorithm cross-spectral estimation has significantly improved, greatly reducing the amount of computation and is more conducive to real-time online computing.

O2: A novel combined online and offline computing system for the ALICE Experiment after 2018

ALICE (A Large Ion Collider Experiment) is a detector dedicated to the studies with heavy ion collisions exploring the physics of strongly interacting nuclear matter and the quark-gluon plasma at the CERN LHC (Large Hadron Collider). After the second long shutdown of the LHC, the ALICE Experiment will be upgraded to make high precision measurements of rare probes at low pT, which cannot be selected with a trigger, and therefore require a very large sample of events recorded on tape. The online computing system will be completely redesigned to address the major challenge of sampling the full 50 kHz Pb-Pb interaction rate increasing the present limit by a factor of 100. This upgrade will also include the continuous un-triggered read-out of two detectors: ITS (Inner Tracking System) and TPC (Time Projection Chamber)) producing a sustained throughput of 1 TB/s. This unprecedented data rate will be reduced by adopting an entirely new strategy where calibration and reconstruction are performed online, and only the reconstruction results are stored while the raw data are discarded. This system, already demonstrated in production on the TPC data since 2011, will be optimized for the online usage of reconstruction algorithms. This implies much tighter coupling between online and offline computing systems. An R&D program has been set up to meet this huge challenge. The object of this paper is to present this program and its first results.

Models for Online Computing in Developing Countries: Issues and Deliberations

The implementation of computerized health information systems (HIS) across the African continent has had mixed success over the past 20 years. Many countries have been left with non-functional systems which cannot be adapted to meet current health information demands because funding is exhausted, the source code for legacy systems is not available and the challenge of maintaining complex and distributed systems in resource-poor environments has simply proved too great. The expansion of Internet connectivity in Africa has enabled a new model of provisioning systems using the web which may prove to be more robust and scalable. This paper uses the case of a new web-based HIS in Ghana to illustrate the opportunities and challenges of this new model. We discuss how the HIS in Ghana was materialized through an act of “improvized outsourcing” according to Ciborra [(1999). Notes on improvisation and time in organizations. Accounting, Management and Information Technologies, 9(2), 77–94], improvization is called upon in urgent situations “when plans and procedures fail” (p. 77). Such an urgent situation took place in Ghana when the data center intended for hosting of the HIS server was not operational in time for the national rollout. Through an act of improvization, hosting of the server was outsourced to a private company in Accra. Silva (2002) [Outsourcing as an improvisation: A case study in Latin America. The Information Society, 18(2), 129–138] argues that power is essential in understanding why outsourcing improvizations succeed or fail, and in light of this we discuss what empowering factors that enabled the successful improvization in Ghana and the role of improvization and outsourcing for the long-term sustainability of system.

A Computationally Efficient Stabilizing Model Predictive Control of Switched Systems

Many applications in engineering exhibit switching character due to discrete and continuous aspects in their dynamic behavior. Switching characteristics of hybrid systems bring discontinuity and nonlinearity in their course of operation and pose major challenges in developing stabilizing Model Predictive Control (MPC) for them. For Piecewise Affine (PWA) Systems, the MPC problem requires on-line solution of Mixed Integer Programs (MIPs) for obtaining the input profile. Since, complexity of the optimization problem that needs to be solved in MPC increases combinatorially with respect to the integer variables, on-line computing of MPC control law for large scale problems and/or problems with large horizons is expensive. In this paper we, propose a MPC formulation, under the popular framework of terminal cost - terminal set MPC, which enables tuning the complexity of the control algorithm. The proposed approach introduces an idea of a pre-terminal set, within which the inputs have enough power to trap states inside it. Since the pre-terminal set lies in the terminal mode which contains origin, this eliminates the need for binary decision variables to model mode transitions after the trajectory enters in pre-terminal set, thereby reducing the on-line complexity although at the expense of optimality. Examples are presented to illustrate the computational benefits of the proposed MPC strategy over existing MPC.

A Comparative Study: Data compression on TANGLISH Natural Language Text

In this age of information and in the era of distributed on-line and mobile computing, one thing is on the rise at an exponential rate is storage space for information. Growing office automation, digitizing libraries, on-line business transactions, and Meta data storage we need a huge storage space. Since more and more new users become a part of the Internet society the significance of data transmission develops to a great extent as never prior to. If data to be stored or transmitted represented efficiently this can be conquered. Data compression techniques are playing a vital role in representing the information. This paper investigates the use of lossless data compression on the Tanglish language text and compares the performance based upon Huffman coding.

Let’s Leave the Bias to the Mainstream Media: A Wikipedia Community Fighting for Information Neutrality

Let’s Leave the Bias to the Mainstream Media: A Wikipedia Community Fighting for Information Neutrality

System administration of ATLAS TDAQ computing environment

This contribution gives a thorough overview of the ATLAS TDAQ SysAdmin group activities which deals with administration of the TDAQ computing environment supporting High Level Trigger, Event Filter and other subsystems of the ATLAS detector operating on LHC collider at CERN. The current installation consists of approximately 1500 netbooted nodes managed by more than 60 dedicated servers, about 40 multi-screen user interface machines installed in the control rooms and various hardware and service monitoring machines as well. In the final configuration, the online computer farm will be capable of hosting tens of thousands applications running simultaneously. The software distribution requirements are matched by the two level NFS based solution. Hardware and network monitoring systems of ATLAS TDAQ are based on NAGIOS and MySQL cluster behind it for accounting and storing the monitoring data collected, IPMI tools, CERN LANDB and the dedicated tools developed by the group, e.g. ConfdbUI. The user management schema deployed in TDAQ environment is founded on the authentication and role management system based on LDAP. External access to the ATLAS online computing facilities is provided by means of the gateways supplied with an accounting system as well. Current activities of the group include deployment of the centralized storage system, testing and validating hardware solutions for future use within the ATLAS TDAQ environment including new multi-core blade servers, developing GUI tools for user authentication and roles management, testing and validating 64-bit OS, and upgrading the existing TDAQ hardware components, authentication servers and the gateways.

The ATLAS Level-1 Central Trigger System in operation

The ATLAS Level-1 Central Trigger (L1CT) system is a central part of ATLAS data-taking. It receives the 40 MHz bunch clock from the LHC machine and distributes it to all sub-detectors. It initiates the detector read-out by forming the Level-1 Accept decision, which is based on information from the calorimeter and muon trigger processors, plus a variety of additional trigger inputs from detectors in the forward regions. The L1CT also provides trigger-summary information to the data acquisition and the Level-2 trigger systems for use in higher levels of the selection process, in offline analysis, and for monitoring.In this paper we give an overview of the operational framework of the L1CT with particular emphasis on cross-system aspects. The software framework allows a consistent configuration with respect to the LHC machine, upstream and downstream trigger processors, and the data acquisition. Trigger and dead-time rates are monitored coherently on all stages of processing and are logged by the online computing system for physics analysis, data quality assurance and operational debugging. In addition, the synchronisation of trigger inputs is watched based on bunch-by-bunch trigger information. Several software tools allow to efficiently display the relevant information in the control room in a way useful for shifters and experts. We present the overall performance during cosmic-ray data taking with the full ATLAS detector and the experience with first beam in the LHC.

On-line computing of PI/lead compensators for industry processes with gain and phase specifications

Abstract In this paper, an on-line computing method is proposed for industry processes. Systematic on-line computing rules are developed for getting parameters of proportional plus integration and lead compensators. The performance of the compensated systems can be evaluated by specified phase margins and gain margins. The parameters of the found compensator can be re-computing if they are necessary. Four numerical examples give the proposed method provides better performance and robustness than those of other mentioned on-line computing methods.

Turing oracle machines, online computing, and three displacements in computability theory

We begin with the history of the discovery of computability in the 1930’s, the roles of Gödel, Church, and Turing, and the formalisms of recursive functions and Turing automatic machines ( a -machines). To whom did Gödel credit the definition of a computable function? We present Turing’s notion [1939, §4] of an oracle machine ( o -machine) and Post’s development of it in [1944, §11], [1948], and finally Kleene-Post [1954] into its present form. A number of topics arose from Turing functionals including continuous functionals on Cantor space and online computations. Almost all the results in theoretical computability use relative reducibility and o -machines rather than a -machines and most computing processes in the real world are potentially online or interactive. Therefore, we argue that Turing o -machines, relative computability, and online computing are the most important concepts in the subject, more so than Turing a -machines and standard computable functions since they are special cases of the former and are presented first only for pedagogical clarity to beginning students. At the end in §10–§13 we consider three displacements in computability theory, and the historical reasons they occurred. Several brief conclusions are drawn in §14.

Increasing Reliability of Intelligent Manufacturing Systems by Adaptive Optimization and Safety Supervision

For concurrent consideration of reliability and safety of manufacturing systems on the one hand, and flexibility and performance on the other, a specialized control architecture was proposed recently. It consists of a strategic controller for online computing (sub-)optimal control strategies under consideration of dynamic models, safety specifications, and learned knowledge. The second building block is an operational controller for providing certified safety when dealing with behaviors that are not completely predictable, for instance in case of faults. This paper extends the architecture by a specific technique for the strategic controller: For the case of an intelligent manufacturing system which reacts adaptively to a human operator, control trajectories for a robot arm are computed online such that collision with the operator is excluded. The computation is based on solving a mixed-integer programming problem that takes a dynamic safety area around the operator into account as constraint.

A hierarchical intrusion detection model based on the PCA neural networks

Most of existing intrusion detection (ID) models with a single-level structure can only detect either misuse or anomaly attacks. A hierarchical ID model using principal component analysis (PCA) neural networks is proposed to overcome such shortages. In the proposed model, PCA is applied for classification and neural networks are used for online computing. Experimental results and comparative studies based on the 1998 DARPA evaluation data sets are given, which show the proposed model can classify the network connections with satisfying performance.

DESIGNING HUMAN-CENTRED UBIQUITOUS COMPUTING

We are entering the age of Ubiquitous Computing, and its most distinguished advantage is invisibility of computing. The essence of invisible computing is the invisibility of Human-computer Interaction, as people can focus their attention on the content instead of the tools they are using. This paper studies how to make computers invisible, and proposes a framework of online invisible computing and offline invisible computing. Online invisible computing is Intelligent Human Computer Interaction, where the computers function as intelligent agents; whereas offline invisible computing as in Natural Human Computer Interaction, people are able to use the computers without much conscious effort. This paper focuses the study on offline invisible computing which needs only minimal users' attention when the users are using computers. The paper attempts to realize invisible computing with Affordances, especially designing Action Affordances in computers. In the Ubiquitous Computing age, the computers would not only be invisible but also be embedded in the environment where people are living, so Human-Computer Interaction could not be separated from the environment any more; User & Environment Centred Design (UECD), a new designing method for ubiquitous computing is also proposed in this paper. A Pen Based User Interface system is developed as the first step to invisible computing.

On-line variable live-adjusted displays with internal and external risk-adjusted mortalities. A valuable method for benchmarking and early detection of unfavourable trends in cardiac surgery

Benchmarking and early detection of unfavourable trends. We implemented a dedicated project-orientated data warehouse, which continuously supplies data for on-line computing of the variable live-adjusted displays (VLADs). To calculate the expected cumulative mortality, we used the multi-variate logistic regression model of the EuroSCORE model. In addition to the external EuroSCORE standard, we calculated a centre-specific risk score for internal standards by analysing the data of 9135 patients, which enables both internal and external comparisons. The VLADs are embedded into the multi-purpose web-based information portal, so that the physicians can investigate several types of VLADs interactively: performance of different types of surgery and individual surgeons for different time intervals. We investigated clinically important events such as modification of operative techniques and personnel changes of the team by the VLADs. We found transient declines in the performance curves during major changes in patient management, indicating that systemic--rather than accidental or patient related factors--were involved in the mortality risk. The internal standard line represents these clusters more clearly than the external line. We evaluated examples of how periods of increased risk could be monitored by the VLAD curves: (1) the introduction of OPCAB surgery; (2) training of surgeons; (3) staff changes and staff-related management. On-line VLADs based on a day-to-day updated database, displaying both internal and external standards, are a helpful visualisation tool for earlier detection of unfavourable trends. They enable the surgeon teams and clinical management to take countermeasures at an early stage.

Analysis of ventricular fibrillation signals for the evaluation of defibrillation success in the treatment of ventricular fibrillation

Precise detection of ventricular fibrillation (VF), reliable prediction of defibrillation success and adjustment of the discharge waveform to the patient's transthoracic impedance may contribute to a reduction of electricity-associated myocardial injury caused by unnecessary counter shocks. Specifically, asystole thresholds distinguish between VF and asystole, and thus prevent unnecessary defibrillation attempts. We reviewed various studies and manufacturer characteristics regarding the parameters and algorithms for analyzing arrhythmia ECG signals. Asystole threshold values of several defibrillator manufacturers were collected and a literature review was performed including the following parameters: amplitude, frequency, bispectral analysis, amplitude spectrum area, wavelets, nonlinear dynamics, N(alpha)histograms, and combinations of various parameters. The manufacturer dependent asystole thresholds vary substantially. We show ways to optimize an ECG-based analysis for the next technological generation of defibrillators. During advanced cardiac life support (ACLS) the probability of defibrillation success should be estimated. Optimal defibrillation waveform, depending on transthoracic resistance, should be individually determined. In case of prolonged VF with a low ECG amplitude defibrillation should not be attempted unless coronary perfusion has been improved by further measures of ACLS. The combined evaluation of VF amplitude and frequency is effective in predicting defibrillation success. Estimation of further parameters is potentially useful for guiding optimal timing of defibrillation. At present, the implementation of most parameters in out-of-hospital cardiopulmonary resuscitation (CPR) is limited by the lack of technical feasibility of online computing. Analysis of VF ECG signals should allow adequate VF detection as well as prediction of defibrillation success. Suitable asystole thresholds for analysis of ECG signals have to be determined, and the adverse effects of CPR associated artefacts on data analysis have to be reduced. Analysis of VF ECG signals is a precondition of individually optimized defibrillation and may contribute substantially to an increased quality of CPR.

PHENIX on-line and off-line computing

Data handling in PHENIX is carried out by the On-Line Computing System (ONCS) and Off-Line Computing System (Off-Line). ONCS provides the overall control and monitoring of the front-end electronics, trigger and data acquisition system and detector ancillary systems. It configures and initializes the on-line system, monitors and controls the data flow, coordinates calibration processes, interlocks the data acquisition process with the slow control subsystems and performs a number of other functions. ONCS uses CORBA software to monitor and control the hardware. Off-Line provides all aspects of data handling not directly connected to the collection of data and monitoring, such as event simulation and reconstruction, data analysis and information management. The impact of the unprecedented data volumes on the design is presented, along with a detailed discussion of the tasks and methods of simulating, obtaining and monitoring the data.

US information retrieval system evolution and evaluation (1945-1975)

Information retrieval has evolved through four phases: manual and mechanical devices; off line computing; online computing and vendor access; and distributed, networked, and mass computing. The article primarily addresses the first three phases. We examine IR systems in terms of four basic functions within a broader communications system context: analysis of document information content including description of document elements (such as author, title, volume, and so on), abstracting, indexing, and other processes; identification and location of sources of documents through bibliographic browsing and searching; evaluation and assessment of bibliographic search output such as screening of bibliographic descriptions; and provision of physical access to document information content through various media such as print on paper, microform, and screen displays.

Chaos Detection using Time Series Data and N. N Control in Vecter Controlled System.

The induction motor is superior to dc motor in maintenance. Though the control of induction motor is much more difficult than that of dc motor, it is currently used for realization of so-called vector control method. Though precise parameters are necessary for the vector control method, but it is generally difficult to obtain the precise values. Therefore, there are often identified errors in parameters. Then, the effect of the nonlinear terms remains, and it is known that chaotic motions may occur in the system. As chaotic motion isn't necessarily desired for the system, it is necessary to remove the chaotic motion when this occurs. In this paper, the existence of chaotic motion in this system can be verified, and it is detected from time series data. Next, a control method of chaotic motion using neural networks is proposed in order to remove the chaotic behavior. This control method can control at a target value by on-line computing.

Programmable processor for on-line computingof inverse Haar transform

A processor for the one-dimensional inverse Haar transform (1D-IFHT) programmable for N = 8 up to N = 1024, with low latency data flow is presented. It enables on-line computing of both the normalised and the non-normalised IFHT to be performed, with very low nrmse.