Genoveffa Tortora

Recovering traceability links in software artifact management systems using information retrieval methods

The main drawback of existing software artifact management systems is the lack of automatic or semi-automatic traceability link generation and maintenance. We have improved an artifact management system with a traceability recovery tool based on Latent Semantic Indexing (LSI), an information retrieval technique. We have assessed LSI to identify strengths and limitations of using information retrieval techniques for traceability recovery and devised the need for an incremental approach. The method and the tool have been evaluated during the development of seventeen software projects involving about 150 students. We observed that although tools based on information retrieval provide a useful support for the identification of traceability links during software development, they are still far to support a complete semi-automatic recovery of all links. The results of our experience have also shown that such tools can help to identify quality problems in the textual description of traced artifacts.

Development and evaluation of a virtual campus on Second Life: The case of SecondDMI

Video games and new communication metaphors are quickly changing todays young people habits. Considering the actual e-learning scenarios, embedded in a fully technological enabled environment it is crucial to take advantage of this kind of capabilities to let learning process gain best results. This paper presents a virtual campus created using Second Life which provides four distinct types of virtual space: common student campus, collaborative zones, lecture rooms and recreational areas. Second Life environments and objects have been designed and programmed to support synchronous lectures and collaborative learning. The Second Life virtual world has also been equipped with supporting tools enabling students and teachers to navigate among multimedia contents. Second Life and an ad-hoc developed Moodle plug-in have been integrated to naturally enrich the environment with LMS services, exploiting this 3D world to increase the interaction and communication opportunities between teachers and students, and among students, principally favoring planned and unplanned social encounters. We have conducted an experiment involving university students aiming at evaluating Second Life synchronous distance lectures in the proposed learning environment. The evaluation has been conducted considering that, in a 3D multi-user virtual environment, learning is strongly related to the user perception of belonging to a learning community, as well as to the perception of awareness, presence and communication. The results of the evaluation are very positive.

Class point: an approach for the size estimation of object-oriented systems

In this paper, we present an FP-like approach, named class point, which was conceived to estimate the size of object-oriented products. In particular, two measures are proposed, which are theoretically validated showing that they satisfy well-known properties necessary for size measures. An initial, empirical validation is also performed, meant to assess the usefulness and effectiveness of the proposed measures to predict the development effort of object-oriented systems. Moreover, a comparative analysis is carried out, taking into account several other size measures.

Assessing IR-based traceability recovery tools through controlled experiments

We report the results of a controlled experiment and a replication performed with different subjects, in which we assessed the usefulness of an Information Retrieval-based traceability recovery tool during the traceability link identification process. The main result achieved in the two experiments is that the use of a traceability recovery tool significantly reduces the time spent by the software engineer with respect to manual tracing. Replication with different subjects allowed us to investigate if subjects’ experience and ability play any role in the traceability link identification process. In particular, we made some observations concerning the retrieval accuracy achieved by the software engineers with and without the tool support and with different levels of experience and ability.

Wiimote and Kinect: gestural user interfaces add a natural third dimension to HCI

The recent diffusion of advanced controllers, initially designed for the home game console, has been rapidly followed by the release of proprietary or third part PC drivers and SDKs suitable for implementing new forms of 3D user interfaces based on gestures. Exploiting the devices currently available on the game market, it is now possible to enrich, with low cost motion capture, the user interaction with desktop computers by building new forms of natural interfaces and new action metaphors that add the third dimension as well as a physical extension to interaction with users. This paper presents two systems specifically designed for 3D gestural user interaction on 3D geographical maps. The proposed applications rely on two consumer technologies both capable of motion tracking: the Nintendo Wii and the Microsoft Kinect devices. The work also evaluates, in terms of subjective usability and perceived sense of Presence and Immersion, the effects on users of the two different controllers and of the 3D navigation metaphors adopted. Results are really encouraging and reveal that, users feel deeply immerse in the 3D dynamic experience, the gestural interfaces quickly bring the interaction from novice to expert style and enrich the synthetic nature of the explored environment exploiting user physicality.

Effort estimation modeling techniques: a case study for web applications

A reliable effort estimation is crucial for a successful web application development planning. Several approaches exist to address this issue. Among them, the algorithmic approach is one of the most widely used and investigated methods. It is based on suitable effort prediction models which relate the development effort with project characteristics. The size represents one of the most interesting characteristics of software products and several measures can be defined in order to estimate the size of web systems. Moreover, several techniques have been proposed in the literature to build the effort prediction models. Thus, of special interest should be to establish the most effective size measures to be employed in effort prediction models and the most suitable techniques for the model construction. To this aim some empirical studies have been undertaken so far. Since it is widely recognized that several investigations should be performed to verify/confirm empirical results, in the paper we will report on an empirical analysis we have carried out by exploiting data coming from 15 web projects developed by a software company. In particular, for the analysis we have considered two sets of size measures: Length Measures (e.g. number of pages, number of medias, number of client and server side scripts) and Functional Measures (e.g. external input, external output, external query). Moreover, we have employed different techniques, such as Linear Regression, Regression Tree, and Analogy-Based Estimation, in order to determine the one that provides the best prediction.

Adams re-trace: traceability link recovery via latent semantic indexing

In this demonstration we present the traceability recovery tool developed in ADAMS, a fine-grained artefact management system. The tool is based on an information retrieval technique, namely latent semantic indexing, and aims at supporting the software engineer in the identification of traceability links between artefacts of different types. The tool has also been integrated in the Eclipse-based client of ADAMS.

FIRST: Fractal Indexing and Retrieval SysTem for Image Databases

We present an image indexing method and a system to perform content-based retrieval in heterogeneous image databases (IDB). The method is based upon the fractal framework of the iterated function systems (IFS) widely used for image compression. The image index is represented through a vector of numeric features, corresponding to contractive functions (CF) of the IFS framework. The construction of the index vector requires a preliminary processing of the images to select an appropriate set of indexing features (i.e. contractive functions). The latter will be successively used to fill in the vector components, computed as frequencies by which the selected contractive functions appear inside the images. In order to manipulate the index vectors efficiently we use discrete Fourier transform (DFT) to reduce their cardinalities and use a spatial access method (SAM), like R*-tree, to improve search performances. The sound theoretical framework underlying the method enabled us to formally prove some properties of the index. However, for a complete validation of the indexing method, also in terms of effectiveness and efficacy, we performed several experiments on a large collection of images from different domains, which revealed good system performances with a low percentage of false alarms and false dismissals. q 1998 Elsevier Science B.V. All rights reserved.

Automating visual language generation

A system to generate and interpret customized visual languages in given application areas is presented. The generation is highly automated. The user presents a set of sample visual sentences to the generator. The generator uses inference grammar techniques to produce a grammar that generalizes the initial set of sample sentences, and exploits general semantic information about the application area to determine the meaning of the visual sentences in the inferred language. The interpreter is modeled on an attribute grammar. A knowledge base, constructed during the generation of the system, is then consulted to construct the meaning of the visual sentence. The architecture of the system and its use in the application environment of visual text editing (inspired by the Heidelberg icon set) enhanced with file management features are reported. >

Evaluating legacy system migration technologies through empirical studies

We present two controlled experiments conducted with master students and practitioners and a case study conducted with practitioners to evaluate the use of MELIS (Migration Environment for Legacy Information Systems) for the migration of legacy COBOL programs to the web. MELIS has been developed as an Eclipse plug-in within a technology transfer project conducted with a small software company [16]. The partner company has developed and marketed in the last 30 years several COBOL systems that need to be migrated to the web, due to the increasing requests of the customers. The goal of the technology transfer project was to define a systematic migration strategy and the supporting tools to migrate these COBOL systems to the web and make the partner company an owner of the developed technology. The goal of the controlled experiments and case study was to evaluate the effectiveness of introducing MELIS in the partner company and compare it with traditional software development environments. The results of the overall experimentation show that the use of MELIS increases the productivity and reduces the gap between novice and expert software engineers.