Distributed Handler Architecture

Thesis (PhD) - Indiana University, Computer Sciences, 2007Over the last couple of decades, distributed systems have been demonstrated an architectural evolvement based on models including client/server, multi-tier, distributed objects, messaging and peer-to-peer. One recent evolutionary step is Service Oriented Architecture (SOA), whose goal is to achieve loose-coupling among the interacting software applications for scalability and interoperability. The SOA model is engendered in Web Services, which provide software platforms to build applications as services and to create seamless and loosely-coupled interactions. Web Services utilize supportive functionalities such as security, reliability, monitoring, logging and so forth. These functionalities are typically provisioned as handlers, which incrementally add new capabilities to the services by building an execution chain. Even though handlers are very important to the service, the way of utilization is very crucial to attain the potential benefits. Every attempt to support a service with an additive functionality increases the chance of having an overwhelmingly crowded chain: this makes Web Service fat. Moreover, a handler may become a bottleneck because of having a comparably higher processing time. In this dissertation, we present Distributed Handler Architecture (DHArch) to provide an efficient, scalable and modular architecture to manage the execution of the handlers. The system distributes the handlers by utilizing a Message Oriented Middleware and orchestrates their execution in an efficient fashion. We also present an empirical evaluation of the system to demonstrate the suitability of this architecture to cope with the issues that exist in the conventional Web Service handler structures

Building Desktop Applications with Web Service in a Message-based MVC Paradigm”, to appear

Over the past decade, classic client side applications with Model-View-Controller (MVC) architecture haven’t changed much but become more complex. In this paper, we present an approach of building desktop applications with Web Services in an explicit message-based MVC paradigm. By integrating with our publish/subscribe messaging middleware, it makes SVG browser (a Microsoft PowerPoint like client application) with Web Service style interfaces universally accessible from different client platforms ─ Windows, Linux, MacOS, PalmOS and other customized ones. Performance data suggests that this scheme of building application around messages is a practical architecture for the next generation Web application client

A Survey Paper on Service Oriented Architecture Approach and Modern Web Services

Service-Oriented Architecture is an architectural design pattern based on distinct pieces of software providing application functionality as services to other applications via a protocol. It is a collection of micro-services which are self-contained and provides unit functionality. The architectural style has the following essential core features which are inter-operability, service abstraction, service discovery, service autonomy, service statelessness re-usability, loose coupling. Service-oriented architectures are not a new thing. The first service-oriented architecture for many people in the past was with the use DCOM (uses RPC – Remote Procedural Calls) and CORBA (uses IIOP protocol) but because of the lack of standards and also with the advent of modern web development (Web 2.0) and the use of mobile phones and their penetration service oriented architecture is being implemented as Web Services (uses mainly HTTP/HTTPS) protocol. Most common implementations of Web Services can be done as SOAP (Simple Object Access Protocol)-based which essentially is a HTTP/HTTPS POST with an XML payload in it. SOAP based web services expose service interface using WSDL (Web Service Description Language) and there is a pre-defined contract via XSD (XML Schema Definition) between the service being exposed and the client side that consumes this service. The other most popular lightweight implementation of web services is using RESTful (Representational State Transfer) architecture where the payload is in JSON (Java Script Object Notation) / XML and uses RESTful style of communication to access resources on the server. So any application written in any language for example C# or C++ or C or Groovy or Java that can make a HTTP call should be able to access the services and since the data is in XML/JSON they can make a sense of data and this way we can re-use services and be inter-operable. The goal of our survey is to delve deeper into SOA principles, key constituents and how Web Services - implementation of SOA has taken this into such a wide spread usage and created a phenomena and various technologies that can be used to develop/consume web services and also about the protocols being used and some common use cases in building re-usable and scalable application architectures using web services

A Majority Vote Based Classifier Ensemble for Web Service Classification

Service oriented architecture is a glue that allows web applications to work in collaboration. It has become a driving force for the service-oriented computing (SOC) paradigm. In heterogeneous environments the SOC paradigm uses web services as the basic building block to support low costs as well as easy and rapid composition of distributed applications. A web service exposes its interfaces using the Web Service Description Language (WSDL). A central repository called universal description, discovery and integration (UDDI) is used by service providers to publish and register their web services. UDDI registries are used by web service consumers to locate the web services they require and metadata associated with them. Manually analyzing WSDL documents is the best approach, but also most expensive. Work has been done on employing various approaches to automate the classification of web services. However, previous research has focused on using a single technique for classification. This research paper focuses on the classification of web services using a majority vote based classifier ensemble technique. The ensemble model overcomes the limitations of conventional techniques by employing the ensemble of three heterogeneous classifiers: Naïve Bayes, decision tree (J48), and Support Vector Machines. We applied tenfold cross-validation to test the efficiency of the model on a publicly available dataset consisting of 3738 real world web services categorized into 5 fields, which yielded an average accuracy of 92 %. The high accuracy is owed to two main factors, i.e., enhanced pre-processing with focused feature selection, and majority based ensemble classification

Network support for multimedia applications using the Netlets architecture

Multi-party multimedia networking applications such as e-commerce, distributed data analysis, Internet TV and advanced collaborative environments feature stringent end-to-end Quality of Service (QoS) requirement and require globally distributed user groups to be interconnected. The variety of delivery requirements posed by such applications are best satisfied using highly customised networking protocols. Hence, a demand for networks to migrate from the current fixed service model to a more flexible architecture that accommodates a wide variety of networking services is emerging. New approaches are required in order to build such service oriented networks. Active networking is one such approach. Active networks treats the network as a programmable computation engine, which provides customised packet processing and forwarding operations for traffic flowing through network nodes. User applications can download new protocols into network elements at runtime, allowing rapid innovation of network services. This thesis makes the case for employing mobile agents to realise an active networking architecture, and describes such an architecture called the Netlets architecture. Netlets are autonomous, mobile components which persist and roam in the network independently, providing predefined network services. This thesis presents the design and implementation of the Netlet node and the service deployment m echanisms that are required to distribute Netlet services in the network. Using the Netlet toolkit, variety of network services were designed to provide network support for multimedia applications in the Internet. A service was implemented to enhance the working of the RSVP protocol in order to provide robust end-to-end QoS support even when the network is only partially QoS provisioned. A scalable and reliable multicast protocol was implemented using the unicast communication model that accommodate heterogeneous receiver terminals. Another service integrates client-side server selection support into web sessions established over the Internet. A service was also developed which provides QoS signalling support to legacy applications. It is shown that these Netlet services are of practical value using performance measurements to assess Netlet responsiveness. Netlet based solutions maybe deployed using existing technologies to provide support for a wide range of multimedia applications in the Internet. The Netlets architecture has thus been shown to allow value-added services to be added to existing networks. By optimising the Netlet architecture implementation, this may be extended to services operating on high-speed (1Gb/s and upwards) links. It thus shows promise as an architecture for building the next generation of active networking solutions

Towards a decentralised common data environment using linked building data and the solid ecosystem

With the emergence of Building Information Modelling (BIM), the construction industry is rapidly catching up with the digital revolution that has boosted productivity in virtually all economic sectors. In current practice, the focus of BIM lies on exchange of documents, often through proprietary formats exchanged using the Industry Foundation Classes (IFC). However, with web technologies such as RDF, OWL and SPARQL, a data- and web-based BIM paradigm becomes within reach. The decentralisation of data and decoupling of information and applications will enhance a more general adoption of Big Open BIM, and is expected to lower the BIM threshold for smaller companies that are active in different phases of the building life cycle. Since one of the promises of the Semantic Web and Linked Data is a highly improved interoperability between different disciplines, it is not necessary to reinvent the wheel for the setup of an infrastructure that supports such a network of decentralised tools and data. In this paper, we evaluate the specifications provided by the Solid project (Inrupt Inc.), a Linked Data-based ecosystem for Social Linked Data. Although the exemplary use case of the Solid ecosystem is decentralisation of data and applications for social network purposes, we notice a considerable overlap with recent ambitions and challenges for a web-based AECO industry (Architecture, Engineering, Construction and Operation). This includes standardised data representations, role- or actor-based authorisation and authentication and the need for modular and extensible applications, dedicated to a specific use case. After a brief introduction to Linked Data and its applications in the building industry, we discuss present solutions for building data management (Common Data Environments, multimodels, etc.). In order to translate these approaches towards a Linked Data context with minimal effort and maximal effect, we then review the Solid specifications for use in a construction-oriented web ecosystem. As a proof of concept, we discuss the setup of a web-service for creation and management of Linked Building Data, generated with the Solid-React generator. This application is envisaged as a bridge between the multiple data stores of different project stakeholders and the end user. It acts as an interface to a distributed Common Data Environment that also allows the generation of multi-models

InfoFilter: Supporting Quality of Service for Fresh Information Delivery

With the explosive growth of the Internet and World Wide Web comes a dramatic increase in the number of users that compete for the shared resources of distributed system environments. Most implementations of application servers and distributed search software do not distinguish among requests to different web pages. This has the implication that the behavior of application servers is quite unpredictable. Applications that require timely delivery of fresh information consequently suffer the most in such competitive environments. This paper presents a model of quality of service (QoS) and the design of a QoS-enabled information delivery system that implements such a QoS modeL The goal of this development is two-fold. On one hand, we want to enable users or applications to specify the desired quality of service requ.irements for their requests so that application-aware QoS adaptation is supported throughout the Web query and search processing. On the other hand, we want to enable an application server to customize how it shou.ld respond to external requests by setting priorities among query requests and allocating server resources using adaptive QoS control mechanisms. We introduce the Infopipe approach as the systems support architecture and underlying technology for building a QoS-enabled distributed system for fresh information delivery

Software Components of an IoT Monitoring Platform in Google Cloud Platform: A Descriptive Research and an Architectural Proposal

As software engineers, it is not an easy task to build a software solution that customers consider easy to use, cost-benefit balanced, secured, high available and prepared for high demand. There are many solutions for building a monitoring platform with these previous attributes and we need to consider all the technical factors to achieve this goal. We proposed an agile methodology for the project management approach, acquired the necessary equipment and services and hired the staff to design and develop a monitoring platform in Google Cloud Platform (GCP) with edge frameworks and technologies. We implemented a software working solution composed of five applications (app) or services and configured services in the GCP: IoT data web service, frontend web app, backend web app, IoT app, and mobile app. They were developed using Python, ReactJS, and Java and deployed in Google Cloud Platform for being used in personal computers, laptops, mobile devices, and IoT devices. We defined this architecture with its main basis in a cloud platform that used the publish/subscribe pattern for efficient data ingestion and reporting

kube-volttron: Rearchitecting the VOLTTRON Building Energy Management System for Cloud Native Deployment

Managing the energy consumption of the built environment is an important source of flexible load and decarbonization, enabling building managers and utilities to schedule consumption to avoid costly demand charges and peak times when carbon emissions from grid generated electricity are highest. A key technology component in building energy management is the building energy management system. Eclipse VOLTTRON is a legacy software platform which enables building energy management. It was developed for the US Department of Energy (DOE) at Pacific Northwest National Labs (PNNL) written in Python and based on a monolithic build-configure-and-run-in-place system architecture that predates cloud native architectural concepts. Yet the software architecture is componentized in a way that anticipates modular containerized applications, with software agents handling functions like data storage, web access, and communication with IoT devices over specific IoT protocols such as BACnet and Modbus. The agents communicate among themselves over a message bus. This paper describes a proof-of-concept prototype to rearchitect VOLTTRON into a collection of microservices suitable for deployment on the Kubernetes cloud native container orchestration platform. The agents are packaged in redistributable containers that perform specific functions and which can be configured when they are deployed. The deployment architecture consists of single Kubernetes cluster containing a central node, nominally in a cloud-based VM, where a microservice containing the database agent (called a "historian") and the web site agent for the service run, and gateway nodes running on sites in buildings where a microservice containing IoT protocol-specific agents handles control and data collection to and from devices, and communication back to the central node