Contract Aware Components, 10 years after

The notion of contract aware components has been published roughly ten years ago and is now becoming mainstream in several fields where the usage of software components is seen as critical. The goal of this paper is to survey domains such as Embedded Systems or Service Oriented Architecture where the notion of contract aware components has been influential. For each of these domains we briefly describe what has been done with this idea and we discuss the remaining challenges.Comment: In Proceedings WCSI 2010, arXiv:1010.233

A design process for harware/software system co-design and its application to designing a reconfigurable FPGA

This paper is going to address the topic of hardware/software systems co-design. The paper will develop two points of view. First, it provides a system-theoretical layout on the problem of designing hardware-software systems. This layout will enable the designer to proceed systematically in optimizing the tradeoff between the desired functionality, available resources and operating conditions. Second, the paper will describe an application of some of the theoretical principles to the design of an embedded automotive system built on a low-cost FPGA

Automated maintenance of service compositions with SLA violation detection and dynamic binding

Web service compositions need to adapt to changes in their constituent web services, in order to maintain functionality and performance. Therefore, service compositions must be able to detect web service failure and performance degradation resulting in the violation of service-level agreements. Automated diagnosis and repair are equally important. However, existing standards and languages for service compositions, such as BPEL, lack constructs for web service monitoring and runtime adaptability, which are pre-requisites for diagnosis and repair. We present a solution for transparent runtime monitoring, as well as automated performance degradation detection, diagnosis, and repair for service compositions expressed as BPEL processes. Our solution uses lightweight monitoring techniques, supports customizable diagnosis and repair strategies, and is compatible with any standards-compliant BPEL engin

Feedback to align teacher and student in a Digital Learning Ecosystem

In this paper, we present an example of a Digital Learning Ecosystem, set up during the first period of the pandemic emergency and then remodelled and re-proposed for hybrid didactics provided afterwards, involving five pedagogical-didactic courses of two universities in central Italy. The central device in this Ecosystem was recursive feedback, which in contexts of didactics mediated by screens can anyhow activate discursive, adaptive, interactive and reflexive dynamics. In order to understand if these aims were pursued, we administered an open-ended questionnaire to 274 students, which was not intended to measure their enjoyment of the method and the environment, but their perceptions regarding the effectiveness of the system on their learning processes, not only at a cognitive level, but also on at an interpersonal and intrapersonal level. The analysis was conducted according to the Structural Topic Model, which allowed us to re-read the responses as a unique corpus of reflective writings, generated by the students after the input provided by the assigned task

FPGA based formation control of multiple ubiquitous indoor robots

University of Technology, Sydney. Faculty of Engineering and Information Technology.This thesis explores the feasibility of using Field-Programmable Gate Array (FPGA) technology for formation control of multiple indoor robots in an ubiquitous computing environment. It is anticipated that in the future, computers will become integrated with people’s daily lives. By way of a hub of surrounding sensors, computers and embedded systems, indoor robots will receive commands from users and execute tasks such as home and office chores in a cooperative manner. Important requirements for such scenarios are power efficiency and computation reliability. The focuses of this project are on exploiting the use of the System-on-Programmable Chip technology and ambient intelligence in developing suitable control strategies for the deployment of multiple indoor robots moving in desired geometric patterns. After surveying the current problems associated with computing systems and robotics, this research was determined to design an ubiquitous robotics system using Field-Programmable Gate Array (FPGA) technology, a serial of the Register-Transfer Level (RTL) and gate level hardware for image processing, and control implementation. Work was done to develop novel, FPGA-feasible algorithms for colour identification, object detection, motion tracking, inter-robot distance estimation, trajectory generation and formation turning. These algorithms were integrated on a single FPGA chip to improve energy efficiency and real-time reliability. With the use of infrared sensors and a global high-resolution digital camera for environment sensing, all computation required for data acquisition, image processing, and closed-loop servo control was then performed on an FPGA chip as an external server. Battery-powered miniature mobile robots, Eyebots, were used as a test-bed for experiments. For realization, all the proposed algorithms were implemented and demonstrated via real-life video snapshots as shown on a PC monitor. These live images were captured from the on-board digital camera and then directly output to the monitor from a VGA interface of the FPGA platform. These together serve as the main contributions of this thesis, in both algorithm development and chip design verified by experiments. The digital circuit designs in the chip were simulated using software specifically developed for FPGAs in order to show the timing waveforms of the chip. Experimental results demonstrated the technical feasibility of the proposed architecture for initialization and maintenance of a line formation of three robots. Effectiveness was verified through the percentage usage of the chip capacity and its power consumption. The prototype of this ubiquitous robotic system could be improved for promising applications in home robotics or for concrete finishing in construction automation

Intelligent transportation systems : a ubiquitous perspective

The concept of intelligent transportation has been devised about acouple of decades ago and still presents many challenging issues to beaddressed so as it can be implemented to its full potential. In this paper weemphasise characteristics such as being user-centred and service oriented tosupport an important facet of future urban transportation: being ubiquitous.Instead of seeing ubiquitous transportation as a completely different paradigm,we discuss on the characteristics that actually turn ITS inherently ubiquitous

Resource management of replicated service systems provisioned in the cloud

Service providers seek scalable and cost-effective cloud solutions for hosting their applications. Despite significant recent advances facilitating the deployment and management of services on cloud platforms, a number of challenges still remain. Service providers are confronted with time-varying requests for the provided applications, inter- dependencies between different components, performance variability of the procured virtual resources, and cost structures that differ from conventional data centers. Moreover, fulfilling service level agreements, such as the throughput and response time percentiles, becomes of paramount importance for ensuring business advantages.In this thesis, we explore service provisioning in clouds from multiple points of view. The aim is to best provide service replicas in the form of VMs to various service applications, such that their tail throughput and tail response times, as well as resource utilization, meet the service level agreements in the most cost effective manner. In particular, we develop models, algorithms and replication strategies that consider multi-tier composed services provisioned in clouds. We also investigate how a service provider can opportunistically take advantage of observed performance variability in the cloud. Finally, we provide means of guaranteeing tail throughput and response times in the face of performance variability of VMs, using Markov chain modeling and large deviation theory. We employ methods from analytical modeling, event-driven simulations and experiments. Overall, this thesis provides not only a multi-faceted approach to exploring several crucial aspects of hosting services in clouds, i.e., cost, tail throughput, and tail response times, but our proposed resource management strategies are also rigorously validated via trace-driven simulation and extensive experiment

Intelligent maintenance management in a reconfigurable manufacturing environment using multi-agent systems

Thesis (M. Tech.) -- Central University of Technology, Free State, 2010Traditional corrective maintenance is both costly and ineffective. In some situations it is more cost effective to replace a device than to maintain it; however it is far more likely that the cost of the device far outweighs the cost of performing routine maintenance. These device related costs coupled with the profit loss due to reduced production levels, makes this reactive maintenance approach unacceptably inefficient in many situations. Blind predictive maintenance without considering the actual physical state of the hardware is an improvement, but is still far from ideal. Simply maintaining devices on a schedule without taking into account the operational hours and workload can be a costly mistake. The inefficiencies associated with these approaches have contributed to the development of proactive maintenance strategies. These approaches take the device health state into account. For this reason, proactive maintenance strategies are inherently more efficient compared to the aforementioned traditional approaches. Predicting the health degradation of devices allows for easier anticipation of the required maintenance resources and costs. Maintenance can also be scheduled to accommodate production needs. This work represents the design and simulation of an intelligent maintenance management system that incorporates device health prognosis with maintenance schedule generation. The simulation scenario provided prognostic data to be used to schedule devices for maintenance. A production rule engine was provided with a feasible starting schedule. This schedule was then improved and the process was determined by adhering to a set of criteria. Benchmarks were conducted to show the benefit of optimising the starting schedule and the results were presented as proof. Improving on existing maintenance approaches will result in several benefits for an organisation. Eliminating the need to address unexpected failures or perform maintenance prematurely will ensure that the relevant resources are available when they are required. This will in turn reduce the expenditure related to wasted maintenance resources without compromising the health of devices or systems in the organisation