Shopping Cart System: Load Balancing and Fault Tolerance in the OSGi Service Platform

The main purpose of this paper was to find a simple solution for load balancing and fault tolerance in OSGi. The challenge was to implement a highly available web application such as a shopping cart system with load balancing and fault tolerance, without having to change the core of OSGi

OSGi in Cloud Environments

This paper deals with the combination of OSGi and cloud computing. Both technologies are mainly placed in the field of distributed computing. Therefore, it is discussed how different approaches from different institutions work. In addition, the approaches are compared to each other

Event monitoring web services for heterogeneous information systems

Abstract—Heterogeneity has to be taken into account when integrating a set of existing information sources into a distributed information system that are nowadays often based on Service-Oriented Architectures (SOA). This is also particularly applicable to distributed services such as event monitoring, which are useful in the context of Event Driven Architectures (EDA) and Complex Event Processing (CEP). Web services deal with this heterogeneity at a technical level, also providing little support for event processing. Our central thesis is that such a fully generic solution cannot provide complete support for event monitoring; instead, source specific semantics such as certain event types or support for certain event monitoring techniques have to be taken into account. Our core result is the design of a configurable event monitoring (Web) service that allows us to trade genericity for the exploitation of source specific characteristics. It thus delivers results for the areas of SOA, Web services, CEP and EDA. Keywords—ECA, CEP, SOA, and Web services

Reverse Engineering of Relational Databases to Ontologies

Abstract. We propose a novel approach to reverse engineering of relational databases to ontologies. Our approach is based on the idea that semantics of a relational database can be inferred, without an explicit analysis of relational schema, tuples and user queries. Rather, these semantics can be extracted by analyzing HTML forms, which are the most popular interface to communicate with relational databases for data entry and display on the Web. The semantics are supplemented with the relational schema and user “head knowledge ” to build an ontology. Our approach can be applied to migrating data-intensive Web pages, which are usually based on relational databases, to the ontologybased Semantic Web

Architecture of Large-Scale Systems

In this paper various techniques in relation to large-scale systems are presented. At first, explanation of large-scale systems and differences from traditional systems are given. Next, possible specifications and requirements on hardware and software are listed. Finally, examples of large-scale systems are presented

Evaluating the RESTfulness of “APIs from the Rough”

Nowadays, REST is the most dominant architectural style of choice at least for newly created web services. So called RESTfulness is thus really a catchword for web application, which aim to expose parts of their functionality as RESTful web services. But are those web services RESTful indeed? This paper examines the RESTfulness of ten popular RESTful APIs (including Twitter and PayPal). For this examination, the paper defines REST, its characteristics as well as its pros and cons. Furthermore, Richardson's Maturity Model is shown and utilized to analyse those selected APIs regarding their RESTfulness. As an example, a simple, RESTful web service is provided as well

Ontologies for Complex Event Processing

In this paper, five ontologies are described, which include the event concepts. The paper provides an overview and comparison of existing event models. The main criteria for comparison are that there should be possibilities to model events with stretch in the time and location and participation of objects; however, there are other factors that should be taken into account as well. The paper also shows an example of using ontologies in complex event processing