SPI success factors within product usability evaluation

This article presents an experience report where we compare 8 years of experience of product related usability testing and evaluation with principles for software process improvement (SPI). In theory the product and the process views are often seen to be complementary, but studies of industry have demonstrated the opposite. Therefore, more empirical studies are needed to understand and improve the present situation. We find areas of close agreement as well as areas where our work illuminates new characteristics. It has been identified that successful SPI is dependent upon being successfully combined with a business orientation. Usability and business orientation also have strong connections although this has not been extensively addressed in SPI publications. Reasons for this could be that usability focuses on product metrics whilst today's SPI mainly focuses on process metrics. Also because today's SPI is dominated by striving towards a standardized, controllable, and predictable software engineering process; whilst successful usability efforts in organisations are more about creating a creative organisational culture advocating a useful product throughout the development and product life cycle. We provide a study and discussion that supports future development when combining usability and product focus with SPI, in particular if these efforts are related to usability process improvement efforts.     

Scalability issues with using FSMWeb to test web applications

Web applications are fast becoming more widespread, larger, more interactive, and more essential to the international use of computers. It is well understood that web applications must be highly dependable, and as a field we are just now beginning to understand how to model and test Web applications. One straightforward technique is to model Web applications as finite state machines. However, large numbers of input fields, input choices and the ability to enter values in any order combine to create a state space explosion problem. This paper evaluates a solution that uses constraints on the inputs to reduce the number of transitions, thus compressing the FSM. The paper presents an analysis of the potential savings of the compression technique and reports actual savings from two case studies.     

Modeling presentation layers of web applications for testing

Web software applications have become complex, sophisticated programs that are based on novel computing technologies. Their most essential characteristic is that they represent a different kind of software deployment—most of the software is never delivered to customers’ computers, but remains on servers, allowing customers to run the software across the web. Although powerful, this deployment model brings new challenges to developers and testers. Checking static HTML links is no longer sufficient; web applications must be evaluated as complex software products. This paper focuses on three aspects of web applications that are unique to this type of deployment: (1) an extremely loose form of coupling that features distributed integration, (2) the ability that users have to directly change the potential flow of execution, and (3) the dynamic creation of HTML forms. Taken together, these aspects allow the potential control flow to vary with each execution, thus the possible control flows cannot be determined statically, prohibiting several standard analysis techniques that are fundamental to many software engineering activities. This paper presents a new way to model web applications, based on software couplings that are new to web applications, dynamic flow of control, distributed integration, and partial dynamic web application development. This model is based on the notion of atomic sections, which allow analysis tools to build the analog of a control flow graph for web applications. The atomic section model has numerous applications in web applications; this paper applies the model to the problem of testing web applications.     

Creating non-minimal triangulations for use in inference in mixed stochastic/deterministic graphical models

We demonstrate that certain large-clique graph triangulations can be useful for reducing computational requirements when making queries on mixed stochastic/deterministic graphical models. This is counter to the conventional wisdom that triangulations that minimize clique size are always most desirable for use in computing queries on graphical models. Many of these large-clique triangulations are non-minimal and are thus unattainable via the popular elimination algorithm. We introduce ancestral pairs as the basis for novel triangulation heuristics and prove that no more than the addition of edges between ancestral pairs needs to be considered when searching for state space optimal triangulations in such graphs. Empirical results on random and real world graphs are given. We also present an algorithm and correctness proof for determining if a triangulation can be obtained via elimination, and we show that the decision problem associated with finding optimal state space triangulations in this mixed setting is NP-complete.     

Global Interoperability Using Semantics, Standards, Science and Technology (GIST)

“Global Interoperability Using Semantics, Standards, Science and Technology” is a concept that is predicated on the assumption that the semantic integration, frameworks and standards that support information exchange, and advances in science and technology can enable information-systems interoperability for many diverse users. This paper recommends technologies and approaches for enabling interoperability across a wide spectrum of political, geographical, and organizational levels, e.g. coalition, federal, state, tribal, regional, non government, and private. These recommendations represent steps toward the goal of the Semantic Web, where computers understand information on web sites through knowledge representations, agents, and ontologies.     

A systematic investigation of geostatistical image fusion for the improvement of the spectral fidelity and spatial detail in Landsat MS imagery

This is the first systematic investigation into the assumptions of image fusion using regression Kriging (RK) – a geostatistical method – illustrated with Landsat MS (multispectral) and SPOT (Satellite Pour l’Observation de la Terre) panchromatic images. The efficiency of different linear regression and Kriging methods in the fusion process is examined by visual and quantitative indicators. Results indicate a trade-off between spectral fidelity and spatial detail preservation for the GLS (generalized least squares regression) and OLS (ordinary least squares regression) methods in the RK process: OLS methods preserve more spatial detail, while GLS methods retain more spectral information from the MS images but at a greater computational cost. Under either OK (ordinary Kriging) or UK (universal Kriging) with either OLS or GLS, the spherical variogram improves spatial details from the panchromatic image, while the exponential variogram maintains more spectral information from the MS image. Overall, RK-based fusion methods outperform conventional fusion approaches from both the spectral and spatial point of view.     

The Koala component model for consumer electronics software

Most consumer electronics today contain embedded software. In the early days, developing CE software presented relatively minor challenges, but in the past several years three significant problems have arisen: size and complexity of the software in individual products; the increasing diversity of products and their software; and the need for decreased development time. The question of handling diversity and complexity in embedded software at an increasing production speed becomes an urgent one. The authors present their belief that the answer lies not in hiring more software engineers. They are not readily available, and even if they were, experience shows that larger projects induce larger lead times and often result in greater complexity. Instead, they believe that the answer lies in the use and reuse of software components that work within an explicit software architecture. The Koala model, a component-oriented approach detailed in this article, is their way of handling the diversity of software in consumer electronics. Used for embedded software in TV sets, it allows late binding of reusable components with no additional overhead     

A Cost-Based Approach to Adaptive Resource Management in Data Stream Systems

Data stream management systems need to adaptively control their resources, since stream characteristics and query workload may vary over time. In this paper, we investigate an approach to adaptive resource management for continuous sliding-window queries that adjusts window sizes and time granularities to keep resource usage within bounds. These two novel techniques differ from standard load shedding approaches based on sampling, as they ensure exact query answers for given user-defined quality of service specifications, even under query reoptimization. In order to quantify the effects of both techniques on the various operations in a query plan, we develop an appropriate cost model for estimating operator resource allocation in terms of memory usage and processing costs. A thorough experimental study not only validates the accuracy of our cost model but also demonstrates the efficacy and scalability of the proposed techniques.     

Influence of age and proximity warning devices on collision avoidance in simulated driving

OBJECTIVE: We conducted a set of experiments to examine the utility of several different uni- and multimodal collision avoidance systems (CASs) on driving performance of young and older adult drivers in a high-fidelity simulator. BACKGROUND: Although previous research has examined the efficacy of different CASs on collision avoidance, there has been a dearth of studies that have examined such devices in different driving situations with different populations of drivers. METHOD: Several different CAS warnings were examined in varying traffic and collision configurations both without (Experiment 1a) and with (Experiment 2) a distracting in-vehicle task. RESULTS: Overall, collision avoidance performance for both potential forward and side object collisions was best for an auditory/visual CAS, which alerted drivers using both modalities. Interestingly, older drivers (60-82 years of age) benefited as much as younger drivers from the CAS, and sometimes they benefited more. CONCLUSION: These data suggest that CASs can be beneficial across a number of different driving scenarios, types of collisions, and driver populations. APPLICATION: These results have important implications for the design and implementation of CASs for different driver populations and driving conditions.