Distributed information systems predominantly have client-server architectures, as does the Web itself. In this article, we review the evolution of the interface of client-server distributed systems, from Messaging and RPC systems that predate the Web, to RESTful Web APIs. We highlight the often overlooked importance of the client-server interface in Web applications, and we reference historic and current systems to discuss the roles of “Web Service” technologies and Service-Oriented Architectures. Considering the future, we point out four directions in which we can see Web APIs moving, including the incorporation of hypermedia and semantics.

May 31, 2014

Managing a RESTful SOA: Providing guidance for service designers and orientation for service consumers

Erik Wilde

Page range: 98-105

Abstract

Managing a Service Oriented Architecture (SOA) requires a well-defined model of what a service actually is, and a structure within which services can be published, documented, and consumed. Without such a definition and organizational structure, it is hard to reap the benefits of a SOA. This paper presents a case study that is closely aligned with how the Web is organized as a SOA, but adds some structure so that service producers and service consumers can be supported in their goals. Using this approach, it is possible to realize the architectural benefits of a RESTful architecture, but can still make sure that the published services follow a set of guidelines and constraints that the SOA is based on.

May 31, 2014

Migration of enterprise applications to the cloud

Tobias Binz, Uwe Breitenbücher, Oliver Kopp, Frank Leymann

Page range: 106-111

Abstract

The migration of existing applications to the cloud enables enterprises to preserve their previous investments and—at the same time—to benefit from the properties of the cloud. This article presents a semi-automated approach for migrating existing enterprise applications to the cloud. Thereby, information about the application is gathered in the source environment, the application is extracted, transformed, and cloud-enabled. This makes the application ready for provisioning in the target cloud. Cloud-enabling an application preserves its business functionality and does not change the fundamental way the application was built.

May 31, 2014

Utilizing architecture models for secure distributed web applications and services

Stefan Wild, Martin Gaedke

Page range: 112-118

Abstract

Today's Web applications are often compositions of distributed yet interconnected services that offer features and data through defined interfaces via standardized protocols. Providing a set of best practices for organizing and utilizing distributed capabilities, the service-oriented architecture design pattern largely contributed to this trend. To react on emerging customer requirements, using agile methodology for Web application development fits well in this context. While it allows promptly responding to change by adjusting the Web application architecture, security must be applied as a holistic approach throughout the entire Web application's lifecycle. There is a need for a flexible, expressive and easy-to-use way to model a Web application's architecture with a strong emphasis on security. This article discusses our work on extending the WebComposition Architecture Model towards a semantically enriched description of a Web application's architecture. For enabling systematic exploitation of such architecture descriptions, we utilize W3C's WebID identity mechanism, the WAC authorization method, and fine-grained filters. We explain how WebID can be applied to allow Web services to mutually authenticate and exchange data, e. g., interface definitions and service parameters, in a controlled way.

May 31, 2014

Concurrent programming in web applications

Benjamin Erb, Frank Kargl, Jörg Domaschka

Page range: 119-126

Abstract

Modern web applications are concurrently used by many users and provide increasingly interactive features. Multi-core processors, highly distributed backend architectures, and new web technologies force a reconsideration of approaches for concurrent programming in order to fulfil scalability demands and to implement modern web application features. We provide a survey on different concepts and techniques of concurrency inside web architectures and guide through viable concurrency alternatives for architects and developers.

May 31, 2014

H2 Proxy – Dynamic load balancing for multi-tenant database systems

Andreas Göbel

Page range: 127-133

Abstract

Software as a service is becoming an increasingly common software delivery model but causes a challenge to service providers related to the design of both applications and data management. Multi-tenant databases allow them to reduce operating costs by leveraging economies of scale. Load balancing of multi-tenant databases with shared-nothing architectures can be done in different tiers of the software stack. In this article, different approaches for this purpose are discussed and the proxy server H2 Proxy is presented. H2 Proxy can be deployed in different tiers and routes tenant requests to database servers corresponding to a tenant placement policy which is changeable at runtime. This article gives an overview of its implementation and demonstrates its efficient routing according to test results.

May 31, 2014

The evolution of identity management using the example of web-based applications

Detlef Hühnlein, Tobias Wich, Johannes Schmölz, Hans-Martin Haase

Page range: 134-140

Abstract

The typical identity management (IdM) techniques used in web-based applications are about to change from application-specific means for identification, authentication and authorization towards the support of standardized, secure and privacy friendly mechanisms for Single Sign-On (SSO). In this paper we outline the different phases of this evolution, which started with the introduction of standardized interfaces for authentication and authorization and allowed to shift these sensitive tasks from the application towards the web application server. In a second phase the interfaces were extended to support authentication and authorization in distributed systems and feature SSO-techniques. The third phase adds identification and aims at providing more security for distributed authentication infrastructures and finally there is a trend towards providing more privacy friendly mechanisms for identity management in the future.

Distinguished Dissertation

May 31, 2014

Learning motor skills: from algorithms to robot experiments

Jens Kober

Page range: 141-146

Abstract

In this thesis, we discuss approaches that allow robots to learn motor skills. Motor skills can often be represented by motor primitives, which encode elemental motions. To date, there have been a number of successful applications of learning motor primitives employing imitation learning. However, many interesting motor learning problems are high-dimensional reinforcement learning problems which are often beyond the reach of current reinforcement learning methods. This thesis contributes to the state of the art in reinforcement learning applied to robotics both in terms of novel algorithms and applications. We show how motor primitives can be employed to learn motor skills on three different levels. All proposed approaches have been extensively validated with tasks such as Ball-in-a-Cup, darts, table tennis, ball throwing, or ball bouncing both in simulation, and on real robots.

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Starting 2025, it - Information Technology will be transferred to Gold Open Access on a year-by-year basis. All articles will thus appear without delay under the Creative Commons license CCBY 4.0. There will be no publication costs for the authors. The Open Access transformation is based on Subscribe-to-Open. You can find more information about the model here.　

it - Information Technology is a strictly peer-reviewed scientific journal. It is the oldest German journal in the field of information technology. Today, the major aim of it - Information Technology is highlighting issues on ongoing newsworthy areas in information technology and informatics and their application. It aims at presenting the topics with a holistic view. It addresses scientists, graduate students, and experts in industrial research and development.

it - Information Technology is the organ of the faculties Technical Informatics and Computer Science in the Life Sciences of the German Informatics Society (GI - Gesellschaft für Informatik e.V.) and faculty Technical Informatics of the Information Technology Society (ITG) within the VDE (Verband der Elektrotechnik, Elektronik und Informationstechnik e.V.).

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