Stavros Koubias

Real-Time Vision-Based System for Textile Fabric Inspection

This paper presents an automatic vision-based system for quality control of web textile fabrics. The general hardware and software platform developed to solve this problem is presented and a powerful algorithm for defect inspection is proposed. Based on the improved binary, textural and neural network algorithms the proposed method gives good results in the detection of many types of fabric defects under real industrial conditions, where the presence of many types of noise is an inevitable phenomenon. A high detection rate with good localization accuracy, low rate of false alarms, compatibility with standard inspection tools and low price are the main advantages of the proposed system as well as the overall inspection approach.

Vertical integration of enterprise industrial systems utilizing web services

The need for interoperability is prominent in the industrial enterprise environment. Different applications and systems that cover the overall range of the industrial infrastructure from the field to the enterprise level need to interoperate. This quest is driven by the enterprise need for greater flexibility and for the wider possible integration of the enterprise systems. This paper presents a distributed system architecture that utilizes dominant state-of-the-art standard technologies, such as workflows, ontologies, and web services, in order to address the above quest in an efficient way.

Architecture Design and Implementation of an Ad-Hoc Network for Disaster Relief Operations

This paper presents an ad-hoc sensor network especially developed for a disaster relief application that provides the rescue teams with a quickly deployable, cost-effective, and reliable tool to collect information about the presence of people in a collapsed building space and the state of the ruins. The hardware/software architecture of the wireless sensor nodes is developed for a low-cost design implementation. Energy efficiency is another objective of this paper, achieved by the combination of a low-power-mode algorithm and a power-aware routing strategy. A selected set of simulation studies indicate a reduction in energy consumption and a significant increase in node lifetime whereas network performance is not affected significantly. Finally, a lightweight management architecture is presented to facilitate autonomous management of ad-hoc sensor networks

ZRP versus DSR and TORA: a comprehensive survey on ZRP performance

Ad hoc networks are characterized by dynamic topology caused by node mobility, multihop wireless connectivity and channel non-deterministic behavior (interference, multipath, hidden and exposed node problem make the wireless channel very difficult to predict). The behavior of ad hoc networks must be analyzed in detail as a result of the pairing of the selected MAC and routing protocols. We focus our studies in the routing layer while closely observing the developments in MAC layer. We present and examine analytical simulation results for the routing protocols DSR, TORA and ZRP especially focusing in ZRP and the impact of some of its most important attributes to network performance, using the well known network simulator OPNET 10.0.PL2

A dynamic context-aware access control architecture for e-services

The universal adoption of the Internet and the emerging web services technologies constitutes the infrastructure that enables the provision of a new generation of e-services and applications. However, the provision of e-services through the Internet imposes increased risks, since it exposes data and sensitive information outside the client premises. Thus, an advanced security mechanism has to be incorporated, in order to protect this information against unauthorized access. In this paper, we present a context-aware access control architecture, in order to support fine-grained authorizations for the provision of e-services, based on an end-to-end web services infrastructure. Access permissions to distributed web services are controlled through an intermediary server, in a completely transparent way to both clients and protected resources. The access control mechanism is based on a Role-Based Access Control (RBAC) model, which incorporates dynamic context information, in the form of context constraints. Context is dynamically updated and provides a high level of abstraction of the physical environment by using the concepts of simple and composite context conditions. Also, the paper deals with implementation issues and presents a system that incorporates the proposed access control mechanism in a web services infrastructure that conform to the OPC XML-DA specification.

Vertical integration of enterprise industrial systems utilizing Web services

The need for interoperability is prominent in the industrial enterprise environment. Different applications and systems that cover the overall range of the industrial infrastructure from the field to the enterprise level need to interoperate. This quest is driven by the enterprise need for greater flexibility and for the wider possible integration of the enterprise systems. The current paper presents an architecture that utilizes three predominant state-of-the-art technologies, namely workflows, ontologies and Web services in order to address the above quest in an efficient way.

Defect detection and classification on web textile fabric using multiresolution decomposition and neural networks

In this paper a pilot system for defect detection and classification of web textile fabric in real-time is presented. The general hardware and software platform, developed for solving this problem, is presented while a powerful novel method for defect detection after multiresolution decomposition of the fabric images is proposed. This method gives good results in the detection of low contrast defects under real industrial conditions, where many types of noise are present. An artificial neural network, trained by a back-propagation algorithm, performs the defect classification in categories.

A generic network management architecture targeted to support home automation networks and home Internet connectivity

This paper proposes a generic network management architecture targeted to support home automation networks and home Internet connectivity for the purpose of control and monitoring. The core of the architecture is a new management protocol residing at the OSI application layer. The paper is structured as follows: state-of-the-art and main objective are primarily presented, and then the proposed architecture and protocol are detailed. Finally, conclusions and open issues are highlighted.

Using cut-through forwarding to retain the real-time properties of Profibus over hybrid wired/wireless architectures

The benefits of wireless extensions in industrial networks are well recognized as long as the integration of the wireless and fieldbus domains will be capable of retaining the real-time and dependability quality of the current wired industrial networking solutions. In this paper, the architecture and the operation of a cut-through forwarding device are described, to be used in broadcasting, hybrid wired/wireless Profibus systems. Analytical models of the delay overhead introduced due to frame forwarding are presented. It is shown that the usage of cut-through forwarding devices relaxes the bit-rate requirements in the radio segments, while it drastically improves the inherent advantages and reduces the drawbacks of hybrid transmission media architectures, which are based on a single Medium Access Control domain.

Modern fieldbus communication architectures for real-time industrial applications

Abstract In this paper we present the latest developments in the field of industrial networking. Within Computer Integrated Manufacturing and Engineering (CIME) environments there is a lot of experience on information systems and manufacturing technologies. The use of this heterogeneous environment often results in long lead times and excessive infrastructure and integration costs. In order to minimize the effects of these heterogeneous environments, systems and methods are developed and applied, making the architectures of the industrial automation systems more “open”. In this paper we will focus on the low-level industrial communication system architectures (fieldbusses). This communication system is regarded as the factorys “nervous system” linking various centers of production activity and allowing flexible and reliable coordination among them. The performance of these communication systems depends strongly on the quality of the MAC-layer protocols (according to the OSI Reference Model). Therefore, selective simulation results are presented for a new high-performance hybrid MAC-layer protocol which is designed especially for hard real-time industrial applications.