Bertalan Forstner

Metamodel-Based Model Transformation with Aspect-Oriented Constraints

Model transformation means converting an input model available at the beginning of the transformation process to an output model. A widely used approach to model transformation uses graph rewriting as the underlying transformation technique. In case of diagrammatic languages, such as the Unified Modeling Language (UML), the exclusive topological matching is found to be not enough. To define precisely the transformation steps beyond the topology of the visual models, additional constraints must be specified which ensures the correctness of the attributes, or other properties to be enforced. Dealing with OCL constraints provides a solution for these unsolved issues, because topological and attribute transformation methods cannot perform and express the problems which can be addressed by constraint validation. The use of OCL as a constraint and query language in modeling is essential. We have shown that it can be applied to model transformations as well. Often, the same constraint is repetitiously applied in many different places in a transformation. It would be beneficial to describe a common constraint in a modular manner, and to designate the places where it is to be applied. This paper presents the problem of crosscutting constraints in transformation rules, and provides an aspect-oriented solution for it. Our approach makes it possible to define constraints separately from the transformation steps, and facilitates specifying their propagation assignment to graph transformation rules. To illustrate the conceptual results, a case study is also provided, which introduces (i) how our approach generates user interface handler source code for mobile platform from a resource model and a statechart diagram, and (ii) how it validates specific properties during the transformation steps using aspect-oriented constraints.

Analyzing computation offloading energy-efficiency measurements

No one disputes that mobile phones have become part of everyday life. Besides phone calling we use them for browsing, messaging, playing games and many other things which were possible only on a desktop computer several years ago. Although these devices are even more “smart”, but due to the growing resource requirements their batteries are discharging in a very short period. This is a very important phenomenon, which forces to find alternative ways to reduce the energy consumption of the smartphones. One of them is the method of “computation offloading” where a part of the processes are executed on a remote device (e.g. in the cloud). The creation of an energy-efficiency model consists of several steps. One of the hardest part is to understand how a smartphone behaves in different circumstances. During the execution of an application every step has its own energy cost. To make the execution energy-efficiency, we need first to measure and analyse these costs. In this paper we are going to present a measurement system which is used to analyse the energy consumption of smartphones. The measurements were made in different scenarios and the goal was to save energy through offloading some tasks. The offloading process is based on scheduling theory.

Target Tracking and Surrounding with Swarm Robots

Nowadays the capabilities of autonomous robots have increased rapidly. However there are situations where one robot is not sufficient. In this paper we will introduce a completely distributed algorithm for tracing and surrounding moving objects or targets using homogenous, medium scaled swarm robots based on local sensing. Our new approach is based on the already known concept of basis behaviors as ubiquitous general building blocks for synthesizing artificial group behavior. Our goal was to generate an algorithm based on simple rules in order to protect a territory from a human intruder. In contrast with the common solution which is employing potential fields, we tried to keep our method as simple as possible by utilizing rule-based control mechanism. We will also present our virtual simulation environment and experimental results.

Energy-efficient computation offloading model for mobile phone environment

The popularity of smartphones is growing every day. Thanks to the more powerful hardware the applications can run more tasks and use broadband network connection, however there are several known issues. For example, under typical usage (messaging, browsing, and gaming) a smartphone can be discharged in one day. This makes the battery life one of the biggest problems of the mobile devices. That is a good motivation to find energy-efficient solutions. One of the possible methods is the “computation offloading” mechanism, which means that some of the tasks are uploaded to the cloud. In this paper we are going to present a new energy-efficient job scheduling model and a measurement infrastructure which is used to analyze the energy consumption of smartphones. Our results are going to be demonstrated through some scenarios where the goal is to save energy. The offloading task is based on LP and scheduling problems.

Target Surrounding Solution for Swarm Robots

In this paper we present a distributed algorithm, which enables to follow and surround moving objects by a swarm of homogenous robots that only use local sensing. We introduce the multi orbit surrounding problem and present a solution for it. We prove that our solution always guarantees that the robots enclose the target and circulate around them. We also evaluate our solution by simulations.

Socio-cognitive gamification: general framework for educational games

Gamification of learning material has received much interest from researchers in the past years. This paper aims to further improve such learning experience by applying socio-cognitive gamification to educational games. Dynamic difficulty adjustment (DDA) is a well-known tool in optimizing gaming experience. It is a process to control the parameters in a video game automatically based on user experience in real-time. This method can be extended by using a biofeedback-approach, where certain aspects of the player’s ability is estimated based on physiological measurement (e.g. eye tracking, ECG, EEG). Here, we outline the design of a biofeedback-based framework that supports dynamic difficulty adjustment in educational games. It has a universal architecture, so the concept can be employed to engage users in non-game contexts as well. The framework accepts input from the games, from the physiological sensors and from the so-called supervisor unit. This special unit empowers a new social aspect by enabling another user to observe or intervene during the interaction. To explain the game-user interaction itself in educational games we propose a hybrid model.

Model-based system development for embedded mobile platforms

With the introduction and popularity of wireless devices, the diversity of the platforms has also been increased. There are different platforms and tools from different vendors such as Microsoft, Sun, Nokia, SonyEricsson and many more. Because of the relatively low-level programming interface, software development for Symbian platform is a tiresome and error prone task, whereas .NET CF contains higher level structures. This paper introduces the problem of the software development for incompatible mobile platforms, moreover, it provides a model-driven architecture (MDA) and Domain Specific Modeling Language (DSML)-based solution. We also discuss the relevance of the model-based approach that facilitates a more efficient software development, because the reuse and the generative techniques are key characteristics of model-based computing. In the presented approach, the platform-independence lies in the graph rewriting-driven visual model transformation. This paper illustrates the creation of model compilers on a metamodeling basis by a software package called Visual Modeling and Transformation System (VMTS), which is an n-layer multipurpose modeling and metamodel-based transformation system. A case study is also presented how model compilers can be used to generate user interface handler code for different mobile platforms from the same platform-independent input models

Supporting Rapid Application Development on Symbian Platform

Programniing for the Symbian OS assumes that developers invest particular and uncommon work, therefore the development lifecycle is rather longer and the costs are usually higher than these of common C++ software development. Dealing with user interface, database or communication, programming is not so straightforward as expected. However, am appropriate developer tool can help the developers to be more efficient and solve the designing and programming difficulties. In this paper we will introduce a rapid application development tool set on the Symbian OS. We model the user interface and the statechart of the mobile applications with a novel tool (Visual Modeling and Transformation System). After this design phase, source code can be generated. We describe a class library that helps the programmers or code generators to produce Symbian source code that is easy to read and maintain

Vision Based Area Discovery with Swarm Robots

Nowadays the need for autonomous robots has increased rapidly. These robots should have different types of sensors, thus their functionality can be extended. In order to process the data coming from the sensors, the robots require a proper processing hardware. However, the cost of a unique on-board controller system, which is able to handle advanced algorithms, is relatively expensive. Our proposal is to attach an inexpensive commercial mobile device to the robot, which has a high-resolution camera and advanced processing unit for different types of operations. In this paper we will present a vision-based model for environment discovery using homogeneous, medium scaled swarm of robots by using the on-board camera of the controller-smart phone. We introduce an extended axiom system based on bio-inspired swarm models, which optimizes the energy consumption of the swarm.

Mobile Platforms and Multi-Mobile Platform Development

Mobile devices and mobile applications have a significant effect on the present and on the future of the software industry. The diversity of mobile platforms necessitates the development of the same mobile application for all major mobile platforms, which requires considerable development effort. Mobile application developers are multiplatform developers, but they prioritize the platforms, therefore, not all platforms are equally important for them. Appropriate methods, processes and tools are required to support the development in order to achieve better productivity. The main motivation of our research activity is to provide a method, which increases the development productivity and the quality of the applications and also reduces the time to market. The paper discusses our model-driven results on the field of multi-mobile platform development.