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Claudio De Capua, Stefano De Falco, Rosario Morello, Nello Polese
A QUALITY MEASUREMENT METHODOLOGY IN PUBLIC UTILITIES: A WATER SUPPLY COMPANY CASE

The present paper gives a quality measurement methodology based on a complex analysis of internal and external indicators and of the relationship existing between the two ones. The result of the proposed methodology application is to dispose of an operative tool to apply appropriate corrective actions to get the quality characteristic monitored on the nominal value. Moreover, an application of the proposed methodology to a water supply company is presented.

Bruno Andò, Emilio Pecora, Nicola Pitrone
REAL-TIME THERMO GRAPHIC ANALYSIS OF VOLCANIC ERUPTIONS

Video surveillance systems are consolidated techniques for the monitoring of eruptive phenomena in volcanic areas. Along with this systems, which use standard video cameras, sometimes people working on this field make use of infrared cameras providing useful information about the thermal evolution of the eruptions. The surveillance of the Mount Etna volcano in Sicily, Italy, is in charge of the Istituto Nazionale di Geofisica e di Vulcanologia - Catania site, and a large amount of monitoring systems are installed along the mountain. Data transmission between these devices and the surveillance sites is a serious task, especially when a large transmission band is required. Moreover, in the case of image storing large memorization capabilities are mandatory. In this paper a new methodology is presented, which aims to improve the performances of surveillance systems in terms of transmission band and storing feature; the proposed methodology is based on the real-time thermo graphic analysis of the monitored area which can provide information on the on going activity and adapt the image transmission rate as well.

Davorin Ambruš, Vedran Bilas, Darko Vasic
A LOW-POWER AUTOMATED MEASUREMENT SYSTEM FOR PULSED EDDY CURRENT BASED INSPECTION OF OIL-WELL CASING

This paper presents a design of a multichannel measurement system for nondestructive inspection of oil-well casing's mechanical properties (i.e. tube wall thickness and inner diameter), employing pulsed eddy current (PEC) technique. A specific feature of the system is its operation in high-temperature environment (typically up to 175°C), which requires simple and robust circuits, low part-count probe design, low power consumption and proper automated measurement algorithms to ensure reliable operation. Based on our previous work on PEC method, we propose an inspection tool, consisted of a simple, low-length three-coil probe, switch-mode power conditioning and transmitter excitation unit, and a low-power data acquisition and telemetry circuit. Preliminary results of our high-temperature functional tests confirm reliable operation of the inspection tool and provide additional verification of the previously proposed PEC methodology for measurements in harsh environments.

Theodoros Alexandropoulos, Vassili Loumos, Eleftherios Kayafas
ESTIMATION OF AMBIENT ILLUMINATION VARIATION BETWEEN COLOUR IMAGES IN THE PRESENCE OF CONTENT CHANGES FOR REAL-TIME ILLUMINATION-INVARIANT CHANGE DETECTION

The task of detecting changes between two image frames is obstructed by the influence of noise and by the existence of ambient illumination variations between the image frames. The former is an inherent property of all electronic imaging devices. The latter appears when changes in camera exposure or white balance settings occur and tends to degrade the efficiency of change detection, if left untreated prior to frame differencing. An additional difficulty lies in the fact that a change detection process is required to accurately detect illumination changes in the presence of both luminance and content changes. In this paper, a luminance invariant change detection method is proposed. It consists of a three-channel brightness correction stage employed for the brightness normalization process and followed by a block-based clustering method, which aims to detect content changes from changes caused by the influence of noise.

G. M. Rocha, G. A. Kyriazis
A SOFTWARE FOR THE EVALUATION OF THE STABILITY OF MEASURING STANDARDS USING BAYESIAN STATISTICS

The manufacturers specify the long term stability of their measuring standards. This parameter is sometimes the largest uncertainty contribution to the overall uncertainty of the standard. An automated system for the evaluation of the stability of measuring standards using Bayesian statistics was developed. For several standards it was verified that the stability estimate is much smaller than the value specified by the manufacturer. The software for data analysis was implemented in language C in the environment LabWindows/CVI.

Theodore Kotsilieris, Stelios Kalogeropoulos, George Karetsos, Vassilis Loumos, Eleftherios Kayafas
PERFORMANCE EVALUATION OF MOBILE AGENT TECHNOLOGY FOR THE CONFIGURATION AND AUDITING OF SLSS IN DIFFSERV ENABLED IP NETWORKS

Nowadays we witness a growing interest for the efficient management of the QoS delivered by the service providers to the Internet users and the usage of SLAs. In such an environment the need to maximise customer satisfaction and reliability and consequently, the deriving obligation to quantify and measure service functions becomes apparent. As traditional centralized NMS manager-agent approach has stretched to its limits, we propose a way of bringing together the static nature of SNMP protocol with the Mobile Agent Technology (MAT) in IP network. In order to address lack of quality of service inherent in current Internet technology, we have chosen differentiated services architecture by implementing the corresponding DiffServ MIB proposed by IETF. The major objective of this paper is to compare the required time to configure and monitor DiffServ domain routers by using MAs and the client-server model. The results drawn from our research lend support to the claim that the performance enhancement by adaptating MAT to rigid network management area depends mainly on the traffic load on the link connecting the managed network with the manager.

S. Kalogeropoulos, G. Karetsos, A. Anagnostopoulos
A METHODOLOGY FOR IMPROVING THE PERFORMANCE OF AGENT-BASED APPLICATIONS THROUGH THE IDENTIFICATION OF THE OPTIMAL NUMBER OF MOBILE AGENTS

The results of the research in the area of Mobile Agent Technology (MAT) have demonstrated the utility of this paradigm in building a wide range of distributed applications and systems. In the past few years, we have witnessed an enthusiastic interest in MAT and plenty of research activities have been carried out. Despite this effort, a number of issues concerning mainly the performance optimisation of agent-based applications are still open. In this paper, we investigate the problem of optimising the number of mobile agents used in an agent-based application in order to improve its performance. As an outcome of our research, we propose a methodology for the decision of the optimum number of mobile agents. To investigate the effect of the number of mobile agents on the performance of agent-based applications and to evaluate the proposed methodology through real measurements, an agent-based distributed application was designed and implemented.

Heikki Jokinen, Risto Ritala
VALUE ASSESSMENT OF MEASUREMENTS IN LARGE MEASUREMENT INFORMATION SYSTEMS

Modern industrial production processes are rich sources of measurement data, acquired in many forms and time periods. The integration of different forms of data and information has become more and more important in process industry. Decisions needed in managing processes in an optimal way force us to utilize the information in a way that maximizes its value. This paper discusses the value assessment of measurements and measurement information in large industrial systems. In particular, probabilistic description of information and the value of uncertainty and information in measurements concerning the performance of operational decision making are discussed.

Andrea Condarcuri, Domenico Grimaldi, Antonino Panella
WORKLOAD MEASUREMENTS AND SYNCHRONISATION INTO A DISTRIBUTED MEASUREMENT LABORATORY

The Distributed Measurement Laboratory (DML) is an heterogeneous system and the workload evaluation is an important aspect to support the performance management strategies in the case the specific requirements must to be respected. The paper describes the method to evaluate the workload of the cooperating hardware equipments of the DML, in particular: (i) the connecting networks, and (ii) the PCs. In this manner useful indexes are achievable to monitor the functioning conditions of the whole DML. The proposed method is based on three different tools known and tested in literature. The first one concerns with the synchronization among the clocks of the different co-operating PCs. The second one concerns the One-Way Delay parameter measurements of the path from the source to the destination. The third one concerns the workload measurement of the CPU of each PC. The results of several experimental tests showing the performance and the accuracy of the method are shown.

Călin Ciufudean, Constantin Filote, Adrian Graur, George Mahalu
SCHEDULING SEQUENTIAL PROCESSES IN TREE NETWORKS

In this paper we focus on the problem of scheduling time-critical data flow over a measuring tree network. We assume that data are operated in discrete time and their arrival and deadline processes are arbitrary. Our goal is to determine a policy which transmits data with minimum extension time at every node (every link) in a tree network. The models existing in the literature do not consider simultaneous performance of various hardware components of a complex system. When a hardware component of the system fails, the system reconfiguration is often less than perfect. On this assumption we introduce an algorithm to model the availability of measuring systems with colored Petri nets (CPN). Regarding the fact that the availability of a measuring cell i (or branch in the network) is calculated with Markov chains, we model our system with stochastic CPN. The utility of our approach in alleviating the computational burden of measuring systems availability is illustrated via a Markov chain structure.

Page 748 of 936 Results 7471 - 7480 of 9356