Petri Selonen

Towards a Model-Driven Process for Designing ReSTful Web Services

Representational State Transfer (ReST) architecture provides a set of constraints that drive design decisions towards architectural properties such as interoperability, evolvability and scalability. Designing a ReSTful service API involves finding resources and their relationships, selecting uniform operations for each resource, and defining data formats for them. It is often a non-trivial exercise to refine a functional specification, expressed in terms of arbitrary actions, to a resource-oriented, descriptive state information content. We argue that this process can be described as a series of model transformations, starting from service functionality and gradually refining the phase products until a ReSTful service API is reached. This paper outlines the process phases, transformations and intermediate models based on our experiences in developing ReSTful services and service APIs at Nokia Research Center. The process captures our understanding on how to systematically transform functional specifications into ReSTful Web service interfaces.

Enabling Rapid Creation of Content for Consumption in Mobile Augmented Reality

As smart phones are getting powerful multimedia devices, with a plethora of sensors, they are the perfect enablers for Augmented Reality, allowing users to see the real world through a magic lens. Augmented Reality applications and services have been typically utilized in a limited number of domains, while adding new content is typically a privilege of developers, as programming skills are required for linking to existing clients or systems. In this paper we study how power users and small businesses can bring their content, advertizing and general data to an Augmented Reality view, with minimal effort. We present three prototyped approaches based on the Image Space mirror world service.

Transformations Have to be Developed ReST Assured

Model transformations do not simply appear. They have to be not-so-simply developed. In early phases of development, there may exist only an intuition or an educated guess on some of the characteristics of the transformation. Instead of assuming a pre-existing complete transformation specification, we embrace change and develop transformations incrementally, gradually refining them into more complete ones as the body of knowledge of the domain grows. We present an iterative process encompassing requirements capture, design and implementation of model transformations. We describe partial transformations as so called transformational patterns and iteratively refine them. We apply the approach to developing a transformation that is used in building APIs that comply with the ReST architectural style.

Bringing user-generated content from Internet services to mobile augmented reality clients

In this paper we describe a system for bringing usergenerated content to mobile augmented reality clients, taking in consideration the metadata required for visualizing it, at a sensor based tracking solution. Our proposal assumes that content is stored in multiple external Internet services, simply treated as a “cloud”, thus making the mobile client service agnostic. A prototype implementation was created for the Image Space service and the learnings of integrating with the popular Flickr service are discussed.

Mixed reality web service platform

This paper presents a RESTful Web service platform for applications for both Web browsers and mobile clients. Having a common service backend makes creating applications fast, simple, and open to third parties. The paper presents two mixed reality applications that have been built on the platform. It summarizes requirements for a mixed reality platform and defines a mixed reality domain model that the platform and applications share. In addition, it describes how the clients can use the REST interface to perform operations on user-generated content, as well as access real-life commercial geo-content such as street-view panoramas and building models.

Experiences in building a RESTful mixed reality web service platform

This paper reports the development of a RESTful Web service platform at Nokia Research Center for building Mixed Reality services. The platform serves geo-spatially oriented multimedia content, geo-data like streetview panoramas, building outlines, 3D objects and point cloud models. It further provides support for identity management and social networks, as well as for aggregating content from third party content repositories. The implemented system is evaluated on architecture qualities like support for evolution and mobile clients. The paper outlines our approach for developing RESTful Web services from requirements to an implemented service, and presents the experiences and insights gained during the platform development, including the benefits and challenges identified from adhering to the Resource Oriented Architecture style.

Developing a ReSTful mixed reality web service platform

This paper discusses the development of a ReSTful Web Service platform for serving Mixed Reality content at Nokia Research Center. The paper gives an overview of the Mixed Reality domain, the requirements for the platform and its implementation. We further outline a method for developing resource oriented web services, beginning with high-level requirements, formalizing them as UML models and refining them to a ReSTful API specification. The approach is demonstrated with detailed examples of designing one particular API subset for Mixed Reality annotations.

Kiuas -- IoT Cloud Environment for Enabling the Programmable World

The Internet of Things (IoT) represents the next significant step in the evolution of the Internet and software development. Until recently, the majority of work in the IoT area focused on data acquisition, analytics and visualization. However, we believe that the evolution towards IoT will eventually result in the creation of a Programmable World in which even the simplest things and most ordinary artifacts are connected to public or private clouds and can be controlled and programmed remotely. In this paper we will introduce Kiuas -- a cloud-based IoT development environment for enabling the Programmable World. The main objective of the Kiuas system is to make software development for complex, large and dynamic topologies of IoT devices as effortless as possible.

From Requirements to a RESTful Web Service: Engineering Content Oriented Web Services with REST

This chapter presents an approach for proceeding from a set of requirements to an implemented RESTful Web service for content oriented systems. The requirements are captured into a simple domain model and then refined into a resource model. The resource model re-organizes the domain concepts into addressable entities: resources and interconnecting links, hypermedia representations, URIs and default HTTP operations and status codes. The approach has emerged from the experiences gained during developing RESTful Web services at Nokia Research Center.

The location graph: towards a symbolic location architecture for the web

In this paper we outline a unified architecture for representing locations of people, places and things in real or virtual worlds, called realms, on the web. Our architecture is based on the location graph that encodes web-level containment and connectedness relationships between locations. The architecture provides an information processing model that allows realm independent queries such as position, range and path, and realm specific queries, such as distance. We present existing systems that are enablers for the proposed architecture. With this architecture we enable a common way to develop location based services and applications across real or virtual realms, avoiding fragmentation.