Search

The use of wireless technology in the field of instrumentation is rapidly expanding due to many reasons such as lower installation and commissioning cost than those incurred by wired technologies and a higher level of security provided by authenticated encrypted data transaction, in addition to a decreased level of system complicity, manifested in eliminating or limiting the need for cabling or its accessories. This article will discuss a proposed technique to perform authenticated wireless WiFi data transmission from multiple sensors to the control station depending on a laboratory stand for the purpose of analysing the principle of coexistence between wireless technologies dedicated to industrial automation, such as wireless HART, and general purpose technologies, such as WiFi and Bluetooth Low Energy BLE. [ABSTRACT FROM AUTHOR]

With a large variety of communication methods and protocols, many software architects face the problem of choosing the best way for services to share information. For communication technology to be functional and practical, it should enable developers to define a complete set of CRUD methods for the processed data. The research team compared this paper's most commonly used data transfer protocols and concepts: REST, WebSocket, gRPC GraphQL and SOAP. A set of web servers was implemented in Python, each using one of the examined technologies. Then, the team performed an automated benchmark measuring time and data transfer overhead for a set of defined operations: creating an entity, retrieving a list of 100 entities and fetching details of one entity. Tests were designed to avoid the results being interfered with by database connection or docker-compose environment characteristics. The research team has concluded that gRPC was the most efficient and reliable data transfer method. On the other hand, GraphQL turned out to be the slowest communication method of all. Moreover, its server and client libraries caused the most problems with proper usage in a web server. SOAP did not participate in benchmarking due to limited compatibility with Python and a lack of popularity in modern web solutions. [ABSTRACT FROM AUTHOR]

To stimulate better user behavior and improve environmental and economic sustainability, it is of paramount importance to make citizens effectively aware of the quality of the environment in which they live every day. In particular, we claim that users could significantly benefit from cost-effective efficient Internet-of-Things (IoT) solutions that provide them with up-to-date live information about air pollution in the areas where they live, suitably adapted to different situations and with different levels of dynamically selected granularities (e.g., at home/district/city levels). Our PeRvasive Environment Sensing and Sharing (PRESS) project has the ambition of increasing users' awareness of the natural environment they live in, as a first step towards improved sustainability; the primary target is the efficient provisioning of real-time user-centric information about environmental conditions in the surroundings, and in particular about air pollution. To this purpose, we have designed, implemented, and thoroughly evaluated the PRESS framework, which is capable of achieving good flexibility and scalability while integrating heterogeneous monitoring data, ranging from sensed air pollution to user-provided quality perceptions. Among the elements of technical originality, PRESS exploits extended Kura IoT gateways with novel congestion detection and recovery mechanisms that allow us to optimize bandwidth allocation between in-the-field PRESS components and the cloud. The reported performance results show the feasibility of the proposed solution, by pointing out not only the scalability and efficiency of the adopted message-based solution that uses Message Queue Telemetry Transport (MQTT) andWebSockets, but also the capability of PRESS to quickly identify and manage traffic congestions, thus, ensuring good quality levels to final users. [ABSTRACT FROM AUTHOR]

We examine the implications of end-to-end web application development, in the social web era. The paper describes a distributed architecture, suitable for modern web application development, as well as the interactivity components associated with it. Furthermore, we conducted a series of stress tests, on popular server side technologies. The PHP/Apache stack was found inefficient to address the increasing demand in network traffic. Nginx was found more than 2.5 times faster in input/output (I/O) operations than Apache, whereas Node.js outperformed both. Node.js, although excellent in I/O operations and resource utilization, was found lacking in serving static files using its built in HTTP server, while Nginx performed great at this task. So, in order to address efficiency, an Nginx server could be placed in-front and proxy static file requests, allowing the Node.js processes to only handle dynamic content. Such a configuration can offer a better infrastructure in terms of efficiency and scalability, replacing the aged PHP/Apache stack. Furthermore we have found that building cross platform applications based on web technologies, is both feasible and highly productive, especially when addressing stationary and mobile devices, as well as the fragmentation among them. Our study concludes that Node.js offers client-server development integration, aiding code reusability in web applications, and is the perfect tool for developing fast, scalable network applications. [ABSTRACT FROM AUTHOR]

RFC6455 support, JSON in JavaScript format have been analyzed and studied. The model of the formation of an expert group for decision-making support has been proposed. The process of interacting of software modules is described from the perspective of the processes of coordination of the system. [ABSTRACT FROM AUTHOR]

This paper describes a framework approach and its communication models for the use of HTML5 WebSockets in cross-browser and cross-platform compatible, stationary and mobile, real-time web applications. This includes interoperability, security and reliability as well as server extensions, integration into existing applications and the implementation of WebSocket business logic - from a stand-alone system up to large clusters. [ABSTRACT FROM AUTHOR]

This work reports on the development details and results of an experimental setup for the localization of the attendants of a music festival. The application had to be reporting in real-time the asymmetric crowd density based on the Received Signal Strength Indicator (RSSI) between the attendants' smartphones and an experimental installation of 24 WiFi access points. The impermanent nature of the application led to the implementation of a cloud-based solution, called "STRAND". STRAND is based on Node.js components, which communicate through websockets, collect, process and exchange data and continuously report the produced information to the end-user. To cope with the near real-time requirements, and the volatility of the crowd concentration density, STRAND horizontally scales the trilateration component, i.e. the component that estimates the user location based on distance measurements. STRAND was tested during the festival days in July 2018 and the results show a system that copes with very high loads and achieves the temporal and accuracy requirements the were set. [ABSTRACT FROM AUTHOR]