Business models for the Web: an analysis of top successful web sites

To investigate successful web business models, an original multidimensional framework is defined and applied to a large number of web sites. The framework‚ named BM*Web‚ combines issues already present in existing schema describing business models, with innovative aspects that have not previously been taken into account in those combinations or which are now viewed in a new light. Results of the application of BM*Web to the 500 top list of Alexa (at a speficic time) highlight an articulated picture where more than one success profile exists and not all of them include a web community, although a strong relationship exists between community and success under some conditions. The identification of features that characterize the most successful business models for the Web could be used to define guidelines for company management, once the appropriate profile for a company has been recognised.

Hacia un enfoque ligero para el desarrollo de aplicaciones web de calidad : Una aproximación guiada por calidad para un proceso de desarrollo ligero de aplicaciones web

A medida que el mercado de aplicaciones Web va madurando y con él metodologías y herramientas de desarrollo, las exigencias de calidad sobre productos y procesos son más importantes y frecuentes. También crecen las restricciones de tiempo y presupuesto. Este fenómeno tiende a dejar fuera del mercado a las pequeñas empresas que desarrollan software Web con procesos caóticos y no emplean un modelo de calidad mínimamente definido. Seguramente la brecha que separa un proceso caótico de uno consistente –iterativo, adaptable al contexto- es vista como insalvable, dado que esas organizaciones no disponen del tiempo y los recursos necesarios para afrontarla. Nosotros proponemos una aproximación liviana pero con un enfoque de ingeniería Web a este problema: flexible, progresivo e intuitivo, basado particularmente en modelos empleados para la evaluación de calidad de aplicaciones Web existentes. Para ilustrar nuestra propuesta hacemos referencia a una experiencia que está desarrollándose en un proyecto Italo-Argentino1 y que involucra investigadores y colaboradores con competencias diversas, en un ámbito multidisciplinario. Las primeras conclusiones que extrajimos están relacionadas con la posibilidad de evaluar, rápida y eficazmente, los beneficios de emplear un modelo de calidad como marco de referencia para el desarrollo Web, específicamente para una pequeña organización.Eje: Ingeniería de Software y Bases de Datos (ISBD)Red de Universidades con Carreras en Informática (RedUNCI

Hacia un enfoque ligero para el desarrollo de aplicaciones web de calidad : Una aproximación guiada por calidad para un proceso de desarrollo ligero de aplicaciones web

A medida que el mercado de aplicaciones Web va madurando y con él metodologías y herramientas de desarrollo, las exigencias de calidad sobre productos y procesos son más importantes y frecuentes. También crecen las restricciones de tiempo y presupuesto. Este fenómeno tiende a dejar fuera del mercado a las pequeñas empresas que desarrollan software Web con procesos caóticos y no emplean un modelo de calidad mínimamente definido. Seguramente la brecha que separa un proceso caótico de uno consistente –iterativo, adaptable al contexto- es vista como insalvable, dado que esas organizaciones no disponen del tiempo y los recursos necesarios para afrontarla. Nosotros proponemos una aproximación liviana pero con un enfoque de ingeniería Web a este problema: flexible, progresivo e intuitivo, basado particularmente en modelos empleados para la evaluación de calidad de aplicaciones Web existentes. Para ilustrar nuestra propuesta hacemos referencia a una experiencia que está desarrollándose en un proyecto Italo-Argentino1 y que involucra investigadores y colaboradores con competencias diversas, en un ámbito multidisciplinario. Las primeras conclusiones que extrajimos están relacionadas con la posibilidad de evaluar, rápida y eficazmente, los beneficios de emplear un modelo de calidad como marco de referencia para el desarrollo Web, específicamente para una pequeña organización.Eje: Ingeniería de Software y Bases de Datos (ISBD)Red de Universidades con Carreras en Informática (RedUNCI

Time to Switch to Second-line Antiretroviral Therapy in Children With Human Immunodeficiency Virus in Europe and Thailand.

Background: Data on durability of first-line antiretroviral therapy (ART) in children with human immunodeficiency virus (HIV) are limited. We assessed time to switch to second-line therapy in 16 European countries and Thailand. Methods: Children aged <18 years initiating combination ART (≥2 nucleoside reverse transcriptase inhibitors [NRTIs] plus nonnucleoside reverse transcriptase inhibitor [NNRTI] or boosted protease inhibitor [PI]) were included. Switch to second-line was defined as (i) change across drug class (PI to NNRTI or vice versa) or within PI class plus change of ≥1 NRTI; (ii) change from single to dual PI; or (iii) addition of a new drug class. Cumulative incidence of switch was calculated with death and loss to follow-up as competing risks. Results: Of 3668 children included, median age at ART initiation was 6.1 (interquartile range (IQR), 1.7-10.5) years. Initial regimens were 32% PI based, 34% nevirapine (NVP) based, and 33% efavirenz based. Median duration of follow-up was 5.4 (IQR, 2.9-8.3) years. Cumulative incidence of switch at 5 years was 21% (95% confidence interval, 20%-23%), with significant regional variations. Median time to switch was 30 (IQR, 16-58) months; two-thirds of switches were related to treatment failure. In multivariable analysis, older age, severe immunosuppression and higher viral load (VL) at ART start, and NVP-based initial regimens were associated with increased risk of switch. Conclusions: One in 5 children switched to a second-line regimen by 5 years of ART, with two-thirds failure related. Advanced HIV, older age, and NVP-based regimens were associated with increased risk of switch

Improving the Quality of Conceptual Models with NLP Tools: An Experiment

Conceptual models are used in a variety of areas within Computer Science, including Software Engineering, Databases and AI. A major bottleneck in broadening their applicability is the time it takes to build a conceptual model for a new application. Not surprisingly, a variety of tools and techniques have been proposed for reusing conceptual models (e.g., ontologies), or for building them semi-automatically from natural language descriptions. What has been left largely unexplored is the impact of such tools on the quality of the models that are being created. This paper presents the results of an experiment designed to assess the extent to which a Natural Language Processing (NLP) tool improves the quality of conceptual models, specifically objectoriented ones. Our main experimental hypothesis is that the quality of a domain class model is higher if its development is supported by a NLP system. The tool used for the experiment -- named NL-OOPS -- extracts classes and associations from a knowledge base realized by a deep semantic analysis of a sample text. Specifically, NL-OOPS produces class models at different levels of detail by exploiting class hierarchies in the knowledge base of a NLP system and marks ambiguities in the text. In our experiments, we had groups working with/without the tool, and then compared and evaluated the final class models they produced

NLP-Based Requirements Modeling: Experiments on the Quality of the models

Conceptual models are used in a variety of areas within Computer Science, including Software Engineering, Databases and AI. A major bottleneck in broadening their applicability is the time it takes to build a conceptual model for a new application. Not surprisingly, a variety of tools and techniques have been proposed for reusing conceptual models, e.g. ontologies, or for building them semi-automatically from natural language (NL) descriptions. What has been left largely unexplored is the impact of such tools on the quality of the models that are being created. This paper presents the results of three experiments designed to assess the extent to which a Natural-Language Processing (NLP) tool improves the quality of conceptual models, specifically object-oriented ones. Our main experimental hypothesis is that the quality of a domain class model is higher if its development is supported by a NLP system. The tool used for the experiment – named NL-OOPS – extracts classes and associations from a knowledge base realized by a deep semantic analysis of a sample text. Specifically, NL-OOPS produces class models at different levels of detail by exploiting class hierarchies in the knowledge base of a NLP system and marks ambiguities in the text. In our experiments, we had groups working with and without the tool, and then compared and evaluated the final class models they produced. The results of the experiments – the first on this topic – give insights on the state of the art of linguistics-based Computer Aided Software Engineering (CASE) tools and allow identifying important guidelines to improve their performance. In particular it was possible to highlight which of the linguistic tasks are more critical to effectively support conceptual modelling

Web site quality evaluation: Lightweight or Heavyweight Models?

One of the most critical decisions in a quality evaluation project is to establish the level at which to analyse the characteristics of the Web sites. This choice should be driven by the underlying goals of the evaluation. Scalability and flexibility are thus desiderable features of the models used to evaluate the quality of a Web site. In this paper we describe two separate studies of Regional Tourist Boards in the Alps that were conducted instantiating the meta-model 2QCV3Q (7Loci). Specifically, we will show that the results of the first study - based on a lightweight model - are consistent with those obtained with the more detailed heavyweight model in the second study

Ambiguity Identification and Measurement in Natural Language Texts

Text ambiguity is one of the most interesting phenomenon in human communication and a difficult problem in Natural Language Processing (NLP). Identification of text ambiguities is an important task for evaluating the quality of text and uncovering its vulnerable points. There exist several types of ambiguity. In the present work we review and compare different approaches to ambiguity identification task. We also propose our own approach to this problem. Moreover, we present the prototype of a tool for ambiguity identification and measurement in natural language text. The tool is intended to support the process of writing high quality documents

Market research for requirements analysis using linguistic tools

Numerous studies in recent months have proposed the use of linguistic instruments to support requirements analysis. There are two main reasons for this: (i) the progress made in natural language processing, (ii) the need to provide the developers of software systems with support in the early phases of requirements definition and conceptual modelling. This paper presents the results of an online market research intended (a) to assess the economic advantages of developing a CASE tool that integrates linguistic analysis techniques for documents written in natural language, and (b) to verify the existence of potential demand for such a tool. The research included a study of the language – ranging from completely natural to highly restricted – used in documents available for requirements analysis, an important factor given that on a technological level there is a trade-off between the language used and the performance of the linguistic instruments. To determine the potential demand for such tool, some of the survey questions dealt with the adoption of development methodologies and consequently with models and support tools; other questions referred to activities deemed critical by the companies involved. Through statistical correspondence analysis of the responses, we were able to outline two "profiles" of companies that correspond to two potential market niches which are characterised by their very different approach to software development