A Flexible and Scalable Architecture for Real-Time ANT+ Sensor Data Acquisition and NoSQL Storage

Wireless Personal or Body Area Networks (WPANs or WBANs) are the main mechanisms to develop healthcare systems for an ageing society. Such systems offer monitoring, security, and caring services by measuring physiological body parameters using wearable devices. Wireless sensor networks allow inexpensive, continuous, and real-time updates of the sensor data, to the data repositories via an Internet. A great deal of research is going on with a focus on technical, managerial, economic, and social health issues. The technical obstacles, which we encounter, in general, are better methodologies, architectures, and context data storage. Sensor communication, data processing and interpretation, data interchange format, data transferal, and context data storage are sensitive phases during the whole process of body parameter acquisition until the storage. ANT+ is a proprietary (but open access) low energy protocol, which supports device interoperability by mutually agreeing upon device profile standards. We have implemented a prototype, based upon ANT+ enabled sensors for a real-time scenario. This paper presents a system architecture, with its software organization, for real-time message interpretation, event-driven based real-time bidirectional communication, and schema flexible storage. A computer user uses it to acquire and to transmit the data using a Windows service to the context server

Push-based versus pull-based data transfer in AJAX applications.

Veebipõhistes rakenduses on populaarsust kogunud AJAX ja COMET tehnoloogiad, mis võimaldavad luua interaktiivseid veebirakendusi. COMET funktsionaalsuse saavutamiseks on mitu meetodit, nimelt pikk päring ning lükkamine. Käesoleva bakalaureusetöö eesmärgiks on võrrelda neid erinevaid tehnoloogiaid raamistikus, mille lõid Ali Mesbah et al., kes võrdlesid AJAX-it ning pikka pärimismeetodit oma artikklis „Performance Testing of Data Delivery Techniques for AJAX Applications“. Bakalaureusetöös loodi uus lükkamispõhine test ning võrreldi selle jõudlust teiste raamistikus olevate testidega. Tulemused näitasid, et lükkamispõhine rakendus kasutas väga vähe TCP pakette ning omas väikest latentsust, keskmiselt 1305ms. Samas oli CPU kasutus kõrge ning mõned teated ei jõudnud kasutajani. Tänu nendele tulemustele, arvestades ka teisi lükkamispõhise meetodi puudujääke, leidis autor, et lükkamispõhise meetodi kasutamine pika päringu asemel ei ole kirjutamise hetkel õigustatud.The Internet contains an ever increasing number of interactive applications, powered by technologies like AJAX and COMET. The latter has multiple ways of achieving the desired functionality, namely long-polling and streaming. While there have been many comparisons between AJAX and the traditional model of the web and even AJAX and long-polling, little research has been done comparing streaming to long-polling. This thesis aims to compare the different technologies in a framework created by Ali Mesbah et al., who compared polling and long-polling solutions in their 2008 article „Performance Testing of Data Delivery Techniques for AJAX Applications“. A new streaming test was created and compared with the other tests included in the framework. The results showed that streaming used very little network resources, using only one packet per message after the initial connections were made. Latency was also not an issue as messages were received by the client in 1305ms on average. However CPU usage and data coherence were not as good. Streaming dropped 1-2 messages where long-polling dropped none and the CPU usage was high at unpredictable times. These results, along with other shortcomings of the streaming method, led the author to determine that streaming is not a viable alternative to long-polling or polling at this time

RESTful management system for Wireless Sensor Network devices

The thesis has been conceived at the SigNET laboratory of the University of Padova. The project has consisted on the design and the development of a software system for managing the devices that compose a Wireless Sensor Network. The created software is based on the REST architectural style, so it has been designed to provide the access to the network functionalities by offering web resources to the clients. The heart of the project is focused on the management of the elaborative nodes of the network. These devices have a direct control on the sensor nodes. The developed software runs on them as an internal daemon, with the aim of monitoring the state of the sensors and managing the requests of the users. The project has also included the creation of a Web Application with which integrate the functionalities provided by WebIoT, a multi-platform Web Application created by the SigNET research group. The aim of this part of the work was making the system transparent to the users. All the implementation choices have been made with a particular attention to ensure high levels of modularity, portability and scalabilit

N-Screen Application Framework

Smartphones and tablets with advanced computing ability and connectivity have already become indispensable in our daily lives. As operating systems of these computer-like handheld devices are getting more mature and stable, many users want physically separated devices to interact with one another and with shared resources in real time. Those devices may have the same type of operating systems, such as sharing between android smartphone and tablets. However, sometimes the sharing occurs among different operating systems. A user may want to use a smartphone to control the menu while the image presentation is displaying on the Internet Protocol television (IPTV), as well as the audio on a personal computer. This scenario brings about the motivation of this thesis. This thesis proposes an architecture that allows for sharing resources among many devices with separated screens at real-time. Compared with traditional mobile application framework, instead of the user experience on a specific device, the consistent user experience across multiple devices becomes the key concern. This research introduces a novel approach to implement the classical Model-View-Controller (MVC) framework in a distributed manner with a multi-layered distributed controller. To ensure consistent user experiences across multiple devices with di erent platforms, this research also adopts a channel-based Publish/Subscribe with effective server push state synchronization. The experiments evaluate the portability, message travelling latency improvement and bandwidth optimization. The results of those experiments prove the advantages of the n-Screen Application Framework (NSAF) both in portability that allows deployment on multiple devices from different manufacturers and performance improvement (both in latency and bandwidth consumption) while comparing with traditional data dissemination scenarios

Certification and quality of goods

Sophisticated market relations require, at the present stage, additional guarantees regarding the consumer properties of the goods. Certification is an important means of achieving confidence and trading. The possibilities of different types and forms of certification for quality assurance of products are analyzed. Specification of the mandatory certification and the role of the harmonized standards for conformity assessment with the essential requirements for the products are specified. The main types of voluntary certification at the international, regional and national level are systemized and outlined. The advantages of applying the certification of quality management systems, certification systems for conformity assessment: with national and other standards; with the requirements of international, regional or national certification systems; with relevant environmental requirements. The positive role of certification for the development of market relations, the improvement of the quality of life, the protection of the environment and the health of consumers and the necessity of its wider supply at different levels have been established

API diversity for microservices in the domain of connected vehicles

Web services in the domain of connected vehicles are subject to various requirements including high availability and large workloads. Microservices are an architectural style which can fulfill those requirements by fostering the independence and decoupling of software components as reusable services. To achieve this independence, microservices have to implement all aspects of providing the services themselves, including different API technologies for heterogeneous consumers and supporting features like authentication. In this work, we examine the use of a service proxy that externalizes these concerns into a sidecar that provides multiple APIs and common service functionality in a platform-independent manner. We look at how different kinds of API styles and technologies solve selected classes of problems and how we can translate between API technologies. We design and implement a framework for building gateways that enables the creation and composition of reusable components, in the fashion of Lego bricks, to maximize flexibility, while reducing the effort for building gateway components. We design and implement selected components of common and reusable API functionality enabling us to build a reference setup with a service proxy as a sidecar using our framework. Finally, we evaluate the proposed solution to identify benefits and drawbacks of the approach of using our framework as a service proxy. We conclude that the examined approach provides benefits for the development of many polyglot microservices, but splitting one service into two components adds additional complexity that has to be managed.Web Services für vernetzte Fahrzeuge unterliegen unterschiedlichen Anforderungen, unter anderem einer hohen Verfügbarkeit und einem großen Datendurchsatz. Microservices sind ein Architekturstil, der diesen Anforderungen gerecht werden kann, indem er die Unabhängigkeit und Entkopplung von Softwarekomponenten als wiederverwendbare Services fördert. Zum Erreichen der Unabhängigkeit implementieren Microservices alle Aspekte der Servicebereitstellung eigenständig. Dazu gehört verschiedene API Technologien für heterogene Clients bereitzustellen und unterstützende Funktionalität wie Authentifizierung zu implementieren. In dieser Arbeit wird die Verwendung einer Proxy Komponente vor einem Service untersucht, durch welche die Bereitstellung verschiedener API Technologien und allgemeiner unterstützender Funktionalität aus dem Service extrahiert wird. Die Lösungen verschiedener API Technologien und Stile für ausgewählte Klassen an Problemen werden verglichen und mögliche Umwandlungen der verschiedenen API Technologien werden untersucht. Es wird ein Framework konzeptioniert und implementiert, das die Erstellung von Gateways durch Kombination von wiederverwendbaren Komponenten, wie das Zusammensetzen von Legosteinen, ermöglicht. Dieses Framework sorgt für eine hohe Flexibilität, während es den Aufwand bei der Erstellung von Gateways gering hält. Es werden ausgewählte wiederverwendbare Komponenten entworfen, um eine Referenzimplementierung des Ansatzes umzusetzen, bei der allgemeine Funktionalität in einen parallel laufenden Proxy ausgelagert wird. Dieser Ansatz wird evaluiert, indem Vor- und Nachteile anhand eines mit dem Framework erstellten Proxys identifiziert werden. Das Fazit dieser Arbeit ist, dass dieser Ansatz bei Systemen mit vielen Microservices mit unterschiedlichen Programmiersprachen Vorteile bringt, aber die Trennung eines Services in zwei Komponenten eine nicht unerhebliche Komplexität einführt

PIT Overload Analysis in Content Centric Networks

Content Centric Networking represents a paradigm shift in the evolution and definition of modern network protocols. Many research efforts have been made with the purpose of proving the feasibility and the scalability of this proposal. Our main contribution is to provide an analysis of the Pending Interest Table memory requirements in real deployment scenarios, especially considering the impact of distributed denial of service attacks. In fact, the state that the protocol maintains for each resource request makes the routers more prone to resources exhaustion issues than in traditional stateless solutions. Our results are derived by using a full custom simulator and considering the different node architectures that have been proposed as valid reference models. The main outcomes point out differentiated weaknesses in each architecture we investigated and underline the need for improvements in terms of security and scalabilit