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Showing papers by "Polytechnic University of Milan published in 2007"


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TL;DR: The size distribution of business firms is explained using number and size of firms' constituent components as discussed by the authors, which is a lognormal distribution multiplied by a stretching factor which can lead to a Pareto upper tail.
Abstract: The size distribution of business firms is explained using number and size of firms' constituent components. It is a lognormal distribution multiplied by a stretching factor which can lead to a Pareto upper tail. This result is confirmed empirically.

1,609 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the specific role of different experiential features in the success achieved by some well-known products and suggested an interpretative model to support the marketing manager in generating the proper stimuli to activate the various components of the customer experience.

1,601 citations


Journal ArticleDOI
TL;DR: A rigorous convergence analysis is provided and exponential convergence of the “probability error” with respect to the number of Gauss points in each direction in the probability space is demonstrated, under some regularity assumptions on the random input data.
Abstract: In this paper we propose and analyze a stochastic collocation method to solve elliptic partial differential equations with random coefficients and forcing terms (input data of the model). The input data are assumed to depend on a finite number of random variables. The method consists in a Galerkin approximation in space and a collocation in the zeros of suitable tensor product orthogonal polynomials (Gauss points) in the probability space and naturally leads to the solution of uncoupled deterministic problems as in the Monte Carlo approach. It can be seen as a generalization of the stochastic Galerkin method proposed in [I. Babuscka, R. Tempone, and G. E. Zouraris, SIAM J. Numer. Anal., 42 (2004), pp. 800-825] and allows one to treat easily a wider range of situations, such as input data that depend nonlinearly on the random variables, diffusivity coefficients with unbounded second moments, and random variables that are correlated or even unbounded. We provide a rigorous convergence analysis and demonstrate exponential convergence of the “probability error” with respect to the number of Gauss points in each direction in the probability space, under some regularity assumptions on the random input data. Numerical examples show the effectiveness of the method.

1,597 citations


Journal ArticleDOI
TL;DR: This surgical procedure is a low-invasive therapeutic approach for resolving the late side effects of radiotherapy, and treatment with lipoaspirate transplantation is potentially extended to other forms of microangiopathies.
Abstract: Background: There is evidence that stern cells contribute to the restoration of tissue vascularisation and organ function. The objective of this study was to assess the presence of adipose derived adult stern cells left in their natural scaffold in the purified lipoaspirate and to access the clinical effectiveness of lipoaspirate transplantation in the treatment of radiation side effects. Methods: This study was designed beginning with surgical procedures in 2002 and envisaging a continious patient follow up to 31 months. Twenty consecutive patients undergoing therapy for side effects of radiation treatment wiht severe symptoms or irreversible functiomn damage (LENT-SOMAscale grade 3 and 4) were enrolled. Purified autologous lipoaspirates (60 to 120 cc) taken from a healthy donor site were administered by reperted low-invasive computer-assisted injection. Therapy outcomes were assessed by symptoms classification according to the LENT-SOMA scale, cytofluorrimetric characterization, and ultrastructural evaluation of targeetd tissue. Results: In the isolated stromal vascular fraction of 2 cc of human lipoaspirate, cells with mesenchymal stren cell physical proprieties and immunophenotype were in average 1.07 ± 0.5 percent (n=4), with a clonogenic fraction of 0.139 percent. At least 1.02 × 10 3 colony-forming units-fibroblast were present in cach lipoaspirate. Ultrastructure of target tissue systematically exhibited progressive regeneration, including neovessel formation and improved hydratation. Clinical outcomes led to a systematic improvement or remission of symptoms in all evaluated patients, including otherwise untreatable patients exhibiting initial irreversible functional damage. Conclusions: This surgical procedure is a low invasive therapeutic approach for resolving the late side effects of radiotherapy. According to the proposed hypothesis of the ischernic nature of radiolesions treatment with lipoaspirate transplantation is potentially extended to other forms of microangiopathies.

1,101 citations


Journal ArticleDOI
TL;DR: A new modeling approach to the Web service selection problem that is particularly effective for large processes and when QoS constraints are severe is introduced.
Abstract: In advanced service oriented systems, complex applications, described as abstract business processes, can be executed by invoking a number of available Web services. End users can specify different preferences and constraints and service selection can be performed dynamically identifying the best set of services available at runtime. In this paper, we introduce a new modeling approach to the Web service selection problem that is particularly effective for large processes and when QoS constraints are severe. In the model, the Web service selection problem is formalized as a mixed integer linear programming problem, loops peeling is adopted in the optimization, and constraints posed by stateful Web services are considered. Moreover, negotiation techniques are exploited to identify a feasible solution of the problem, if one does not exist. Experimental results compare our method with other solutions proposed in the literature and demonstrate the effectiveness of our approach toward the identification of an optimal solution to the QoS constrained Web service selection problem

896 citations



Journal ArticleDOI
TL;DR: A scenario with two single-user links, one licensed to use the spectral resource (primary) and one unlicensed (secondary or cognitive), is considered and benefits of relaying strongly depend on the topology of the network.
Abstract: A scenario with two single-user links, one licensed to use the spectral resource (primary) and one unlicensed (secondary or cognitive), is considered. According to the cognitive radio principle, the activity of the secondary link is required not to interfere with the performance of the primary. Therefore, in this paper, it is assumed that the cognitive link accesses the channel only when sensed idle. Moreover, the analysis includes: (1) random packet arrivals; (2) sensing errors due to fading at the secondary link; (3) power allocation at the secondary transmitter based on long-term measurements. In this framework, the maximum stable throughput of the cognitive link (in packets/slot) is derived for a fixed throughput selected by the primary link. The model is modified so as to allow the secondary transmitter to act as a ldquotransparentrdquo relay for the primary link. In particular, packets that are not received correctly by the intended destination might be decoded successfully by the secondary transmitter. The latter can, then, queue and forward these packets to the intended receiver. A stable throughput of the secondary link with relaying is derived under the same conditions as before. Results show that benefits of relaying strongly depend on the topology (i.e., average channel powers) of the network.

397 citations


Journal ArticleDOI
TL;DR: The aim of the experiment was to demonstrate that interferometric synthetic aperture radar (InSAR) measurements can indeed allow a displacement time series estimation with submillimeter accuracy (both in horizontal and vertical directions), provided that the data are properly processed and the impact of in situ as well as atmospheric effects is minimized.
Abstract: This paper presents the results of a blind experiment that is performed using two pairs of dihedral reflectors. The aim of the experiment was to demonstrate that interferometric synthetic aperture radar (InSAR) measurements can indeed allow a displacement time series estimation with submillimeter accuracy (both in horizontal and vertical directions), provided that the data are properly processed and the impact of in situ as well as atmospheric effects is minimized. One pair of dihedral reflectors was moved a few millimeters between SAR acquisitions, in the vertical and east-west (EW) directions, and the ground truth was compared with the InSAR data. The experiment was designed to allow a multiplatform and multigeometry analysis, i.e., each reflector was carefully pointed in order to be visible in both Envisat and Radarsat acquisitions. Moreover, two pairs of reflectors were used to allow the combination of data gathered along ascending and descending orbits. The standard deviation of the error is 0.75 mm in the vertical direction and 0.58 mm in the horizontal (EW) direction. GPS data were also collected during this experiment in order to cross-check the SAR results

364 citations


Proceedings ArticleDOI
05 Sep 2007
TL;DR: An audio-based video surveillance system which automatically detects anomalous audio events in a public square, such as screams or gunshots, and localizes the position of the acoustic source, in such a way that a video-camera is steered consequently.
Abstract: This paper describes an audio-based video surveillance system which automatically detects anomalous audio events in a public square, such as screams or gunshots, and localizes the position of the acoustic source, in such a way that a video-camera is steered consequently. The system employs two parallel GMM classifiers for discriminating screams from noise and gunshots from noise, respectively. Each classifier is trained using different features, chosen from a set of both conventional and innovative audio features. The location of the acoustic source which has produced the sound event is estimated by computing the time difference of arrivals of the signal at a microphone array and using linear-correction least square localization algorithm. Experimental results show that our system can detect events with a precision of 93% at a false rejection rate of 5% when the SNR is 10dB, while the source direction can be estimated with a precision of one degree. A real-time implementation of the system is going to be installed in a public square of Milan.

363 citations


Journal ArticleDOI
01 Dec 2007
TL;DR: This survey has the goal to provide a comprehensive evaluation framework, allowing application designers to compare context models with respect to a given target application, and stress the analysis of those features which are relevant for the problem of data tailoring.
Abstract: Context-aware systems are pervading everyday life, therefore context modeling is becoming a relevant issue and an expanding research field. This survey has the goal to provide a comprehensive evaluation framework, allowing application designers to compare context models with respect to a given target application; in particular we stress the analysis of those features which are relevant for the problem of data tailoring. The contribution of this paper is twofold: a general analysis framework for context models and an up-to-date comparison of the most interesting, data-oriented approaches available in the literature.

349 citations


Journal ArticleDOI
TL;DR: In this paper, the design and fabrication of a single-photon avalanche diode (SPAD) array system for counting and time-tagging single photons by means of a monolithic array sensor is discussed.
Abstract: This is the first of two serial papers dealing on single-photon avalanche diode (SPAD) topics. Aim of the series is to discuss in depth the design and fabrication of our SPAD-A array system for two-dimensional single-photon imaging, able to count and time-tag single photons by means of a monolithic array sensor. This paper deals with the device structure and characterization. The second paper will present the developed fast electronics and will show the overall performance reached in passive, active, and gated regimes. In this first paper we review the working principle and the features of single-photon detector pixels, with particular attention to the monolithic array integration. Then we discuss design criteria, trade-offs, and how to chose operating conditions to attain best performances out of individual pixels. Finally, experimental data will be thoroughly discussed.

Journal ArticleDOI
TL;DR: In this article, the NH3-SCR reactivity over a commercial V2O5-WO3/TiO2 catalyst in a wide range of temperatures and NO/NO2 feed ratios was investigated.
Abstract: We present a systematic study of the NH3-SCR reactivity over a commercial V2O5–WO3/TiO2 catalyst in a wide range of temperatures and NO/NO2 feed ratios, which cover (and exceed) those of interest for industrial applications to the aftertreatment of exhaust gases from diesel vehicles. The experiments confirm that the best deNOx efficiency is achieved with a 1/1 NO/NO2 feed ratio. The main reactions prevailing at the different operating conditions have been identified, and an overall reaction scheme is herein proposed. Particular attention has been paid to the role of ammonium nitrate, which forms rapidly at low temperatures and with excess NO2, determining a lower N2 selectivity of the deNOx process. Data are presented which show that the chemistry of the NO/NO2–NH3 reacting system can be fully interpreted according to a mechanism which involves: (i) dimerization/disproportion of NO2 and reaction with NH3 and water to give ammonium nitrite and ammonium nitrate; (ii) reduction of ammonium nitrate by NO to ammonium nitrite; (iii) decomposition of ammonium nitrite to nitrogen. Such a scheme explains the peculiar deNOx reactivity at low temperature in the presence of NO2, the optimal stoichiometry (NO/NO2 = 1/1), and the observed selectivities to all the major N-containing products (N2, NH4NO3, HNO3, N2O). It also provides the basis for the development of a mechanistic kinetic model of the NO/NO2–NH3 SCR reacting system.

Journal ArticleDOI
TL;DR: Silicon single-photon avalanche diodes (SPADs) are nowadays a solid-state alternative to photomultiplier tubes (PMTs) in single photon counting (SPC) and time-correlated singlephoton counting over the visible spectral range up to 1mum wavelength as discussed by the authors.
Abstract: Silicon single-photon avalanche diodes (SPADs) are nowadays a solid-state alternative to photomultiplier tubes (PMTs) in single-photon counting (SPC) and time-correlated single-photon counting (TCSPC) over the visible spectral range up to 1-mum wavelength. SPADs implemented in planar technology compatible with CMOS circuits offer typical advantages of microelectronic devices (small size, ruggedness, low voltage, low power, etc.). Furthermore, they have inherently higher photon detection efficiency, since they do not rely on electron emission in vacuum from a photocathode as do PMTs, but instead on the internal photoelectric effect. However, PMTs offer much wider sensitive area, which greatly simplifies the design of optical systems; they also attain remarkable performance at high counting rate, and offer picosecond timing resolution with microchannel plate models. In order to make SPAD detectors more competitive in a broader range of SPC and TCSPC applications, it is necessary to face several issues in the semiconductor device design and technology. Such issues will be discussed in the context of the two possible approaches to such a challenge: employing a standard industrial high-voltage CMOS technology or developing a dedicated CMOS-compatible technology. Advances recently attained in the development of SPAD detectors will be outlined and discussed with reference to both single-element detectors and integrated detector arrays.

Journal ArticleDOI
TL;DR: Some pros and cons of adopting Bns for water resource planning and management are analyzed by framing their use within the context of a participatory and integrated planning procedure, and exploring how they can be integrated with other types of models.
Abstract: Bayesian Networks (Bns) are emerging as a valid approach for modelling and supporting decision making in the field of water resource management. Based on the coupling of an interaction graph to a probabilistic model, they have the potential to improve participation and allow integration with other models. The wide availability of ready-to-use software with which Bn models can be easily designed and implemented on a PC is further contributing to their spread. Although a number of papers are available in which the application of Bns to water-related problems is investigated, the majority of these works use the Bn semantics to model the whole water system, and thus do not discuss their integration with other types of model. In this paper some pros and cons of adopting Bns for water resource planning and management are analyzed by framing their use within the context of a participatory and integrated planning procedure, and exploring how they can be integrated with other types of models.

Journal ArticleDOI
TL;DR: In this paper, a time-resolved analysis of threshold voltage and resistance in phase-change memory (PCM) is presented, where the authors show that the threshold voltage for electronic switching of the amorphous chalcogenide determines the boundary between programming and readout operation.
Abstract: The electronic behavior of the chalcogenide material used in phase-change memory (PCM) plays a key role in defining the operation voltages and times of the memory cell. In particular, the threshold voltage for electronic switching of the amorphous chalcogenide determines the boundary between programming and readout operation, while its resistance allows the recognition of the bit status. This paper present a time-resolved analysis of threshold voltage and resistance in a PCM. Both dynamics of threshold voltage and resistance display a fast transient, named recovery behavior, in the first 30 ns after programming. A slower, nonsaturating drift transient is found for longer times. The two transients are discussed referring to electronic and structural rearrangements in the amorphous chalcogenide. Finally, the impact on the device level is considered

Journal ArticleDOI
TL;DR: In this article, the use of copulas in hydrological modeling has been explored and many important results still are to be discovered and/or derived, such as: (1) the calculation of conditional probabilities and their use in bivariate simulation; (2) the calculated level curves of joint distributions; (3) the return periods of bivariate events, both in the conditional and unconditional cases; (4) the definition and calculation of the secondary return period; (5) a trivariate model for the temporal structure of the sequence of storms; (6) the
Abstract: The use of copulas in hydrology is quite recent, and many important results still are to be discovered and/or derived. In this work we present some recent advances in hydrological modeling that exploit copulas. These include: (1) the calculation of conditional probabilities and their use in bivariate simulation; (2) the calculation of the level curves of joint distributions; (3) the calculation of the return periods of bivariate events, both in the conditional and unconditional cases; (4) the definition and calculation of the secondary return period; (5) a trivariate model for the temporal structure of the sequence of storms; (6) the statistical calculation of the storm depth; and (7) the calculation of the convolution variance. Several applications to hydrological data are shown. The models presented here may have important implications in many areas of water resources and hydrologic systems.

Journal ArticleDOI
TL;DR: In this article, the authors analyze the different sources of start-up financing used by NTBFs and investigate several characteristics that may influence the extent of recourse to bank loans, concluding that only a minority of firms resort to outside financing, and especially to bank debt.
Abstract: This paper aims to shed new light on start-up financing of new technology-based firms (NTBFs) and the existence of credit constraints that may negatively affect their activity. For this purpose, we analyze the different sources of start-up financing used by NTBFs and investigate several characteristics that may influence the extent of recourse to bank loans. In the empirical section, we consider a sample composed of 386 Italian NTBFs that operate both in manufacturing and services. We estimate double-censored tobit and bivariate tobit models so as to highlight the determinants of (i) the financial leverage, measured by the ratio of bank debt to total capital, and (ii) the amounts of personal capital and bank loans of firms at start-up, respectively. Our findings support the view that the credit market is imperfect and there exists a financing hierarchy. In fact, only a minority of firms resorts to outside financing, and especially to bank debt. In addition, the level of financial leverage is not random; it increases with an increase of the predicted amount of firms’ total initial capital, while it decreases with variables such as the number of owners and the work experience of founders that are indicative of greater personal wealth available to finance firms’ start-up. Lastly, the size of the bank loans obtained by firms generally is small and it is quite insensitive to demand-side factors that instead determine the amount of personal and total capital, with the notable exception of scale economies in the industry of the start-up. In other words, in accordance with the argument that credit to NTBFs is rationed, the loan supply curve is highly inelastic, even though not perfectly so.

Journal ArticleDOI
TL;DR: In this article, a unifying redox approach is proposed to interpret the overall NO/NO2−NH3 SCR chemistry over V-based catalysts, in which vanadium sites are reduced by the reaction between NO and NH3 and are reoxidized either by oxygen (standard SCR) or by nitrates (fast SCR), with the latter formed via NO2 disproportion over other nonreducible oxide catalyst components.

Journal ArticleDOI
TL;DR: In this paper, a rheology of paste model is applied to the mix design of steel fiber reinforced self-compact concrete (SFRSCC) and the influence of fibers on the grading of solid skeleton, minimum content and rheological properties of the paste required to achieve the required selfcompactability and stability were studied.

Journal ArticleDOI
TL;DR: In this article, the authors present a survey of the application of these technologies to suspensions and running gear, focused upon the complementary issues of control and monitoring, from which they identify the key trends and conclude with a forward look at what is likely to develop over the next few years.
Abstract: Over the last twenty to thirty years, railway vehicle dynamics has changed from being an essentially mechanical engineering discipline to one that is increasingly starting to include sensors, electronics and computer processing. This paper surveys the application of these technologies to suspensions and running gear, focused upon the complementary issues of control (which has been reviewed within Vehicle System Dynamics previously) and monitoring (which has not previously been reviewed). The theory, concepts and implementation status are assessed in each case, from which the paper identifies the key trends and concludes with a forward look at what is likely to develop over the next years.

Journal ArticleDOI
TL;DR: In this paper, the effect of fiber orientation on the fatigue strength of a short glass fiber reinforced polyamide-6 has been investigated with tensile and fatigue tests with specimens extracted from injection moulded plates.

Journal ArticleDOI
TL;DR: In patients with acute myocardial infarction, SES are superior to BMS, reducing the incidence of binary restenosis by 56%, target lesion revascularization by 61%, target vessel rev vascularization by 62%, adverse cardiac events by 59%, and target vessel failure by 53% at 1 year.

Journal ArticleDOI
TL;DR: In this article, the effects of titanium anodic oxidation in a sulphuric acid electrolyte on the crystallinity of the oxide layer and adjust the process parameters, in order to maximize the TiO2 crystalline phase, specially for what concerns the anatase form.

Journal ArticleDOI
TL;DR: In this paper, Raman spectroscopy of rutile nanocrystals embedded in cluster-assembled films produced by supersonic cluster beam deposition is presented. But, the authors show that a phonon confinement model is not adequate to explain the features of the lattice dynamics of RNNs.
Abstract: We report the characterization by Raman spectroscopy of rutile nanocrystals embedded in cluster-assembled $\mathrm{Ti}{\mathrm{O}}_{2}$ films produced by supersonic cluster beam deposition. Thermal annealing of the as-deposited films promotes the growth of rutile and anatase nanoparticles with a dimension distribution peaked around $10\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. We show that a phonon confinement model is not adequate to explain the features of the lattice dynamics of rutile nanocrystals. The coexistence of the two crystalline phases allows us to identify the role of chemical and structural inhomogeneities in the film potentially affecting the Raman spectra. Our results suggest that the lattice dynamics of rutile nanocrystals is influenced by the dielectric constant of the cluster-assembled films.

Journal ArticleDOI
TL;DR: A detailed overview on the energetic and geometric features of Halogen Bonding is given in this article, showing how some of them are quite constant in most of the formed supramolecular complexes (e.g., the angle formed by the covalent and the noncovalent bonds around the halogen atom).
Abstract: Engineering functional materials endowed with unprecedented properties require the exploitation of new intermolecular interactions, which can determine the characteristics of the bulk materials. The great potential of Halogen Bonding (XB), namely any noncovalent interaction involving halogens as electron acceptors, in the design of new and high-value functional materials is now emerging clearly. This Highlight will give a detailed overview on the energetic and geometric features of XB, showing how some of them are quite constant in most of the formed supramolecular complexes (e.g., the angle formed by the covalent and the noncovalent bonds around the halogen atom), while some others depend strictly on the nature of the interacting partners. Then, several specific examples of halogen-bonded supramolecular architectures, whose structural aspects as well as applications in fields as diverse as enantiomers' separation, crystal engineering, liquid crystals, natural, and synthetic receptors, will be fully described. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: PolymChem 45: 1–15, 2007

Journal ArticleDOI
TL;DR: In this article, the effects of stray current on the corrosion behavior of steel in concrete have been studied, with regards to both corrosion initiation and propagation, and it has been shown that DC current can induce corrosion initiation on the reinforcement in the anodic zone only after it has circulated for a certain time, which depends on anodic current density, the presence of chloride in the concrete and interruptions in the current.

Journal ArticleDOI
TL;DR: In this article, the authors focus on the multidimensional frequency analysis of sea storm significant wave height (H), storm duration (D), storm direction (A), and storm interarrival time (I) (i.e., the calm period separating two successive storms).

Journal ArticleDOI
01 Jan 2007
TL;DR: In this paper, the authors constructed reliable surrogates that can reproduce aspects of combustion of JP-8 and Jet-A in laminar non- premixed flows using a semi-detailed chemical-kinetic mechanism.
Abstract: Experimental and numerical studies are carried out to construct reliable surrogates that can reproduce aspects of combustion of JP-8 and Jet-A. Surrogate fuels are defined as mixtures of few hydrocarbon compounds with combustion characteristics similar to those of commercial fuels. The combustion characteristics considered here are extinction and autoignition in laminar non premixed flows. The “reference” fuels used as components for the surrogates of jet fuels are n-decane, n-dodecane, methylcyclohexane, toluene, and o-xylene. Three surrogates are constructed by mixing these components in proportions to their chemical types found in jet fuels. Experiments are conducted in the counterflow system. The fuels tested are the components of the surrogates, the surrogates, and the jet fuels. A fuel stream made up of a mixture of fuel vapors and nitrogen is injected into a mixing layer from one duct of a counterflow burner. Air is injected from the other duct into the same mixing layer. The strain rate at extinction is measured as a function of the mass fraction of fuel in the fuel stream. The temperature of the air at autoignition is measured as a function of the strain rate at a fixed value of the mass fraction of fuel in the fuel stream. The measured values of the critical conditions of extinction and autoignition for the surrogates show that they are slightly more reactive than the jet fuels. Numerical calculations are carried out using a semi-detailed chemical-kinetic mechanism. The calculated values of the critical conditions of extinction and autoignition for the reference fuels and for the surrogates are found to agree well with experimental data. Sensitivity analysis is used to highlight key elementary reactions that influence the critical conditions of autoignition of an alkane fuel and an aromatic fuel.

Journal ArticleDOI
TL;DR: Self-phase-stabilized near-IR pulses have been generated by difference-frequency generation of a filament broadened supercontinuum followed by two-stage optical parametric amplification, suited as a driver for high-order harmonic generation and isolated attosecond pulse production.
Abstract: Ultrabroadband self-phase-stabilized near-IR pulses have been generated by difference-frequency generation of a filament broadened supercontinuum followed by two-stage optical parametric amplification. Pulses with energy up to 1.2 mJ and duration down to 17 fs are demonstrated. These characteristics make such a source suited as a driver for high-order harmonic generation and isolated attosecond pulse production.

Journal ArticleDOI
TL;DR: This article illustrates a conceptual framework that provides modeling facilities for context-aware, multichannel Web applications and shows how high-level modeling constructs can drive the application development process through automatic code generation.
Abstract: Context-aware, multi-channel Web applications are more and more gaining consensus among both content providers and consumers, but very few proposals exist for their conceptual modeling. This article illustrates a conceptual framework that provides modeling facilities for context-aware, multichannel Web applications; it also shows how high-level modeling constructs can drive the application development process through automatic code generation. Our work stresses the importance of user-independent, context-triggered adaptation actions, in which the context plays the role of a “first class” actor, operating independently of users on the same hypertext the users navigate. Modeling concepts are based on WebML (Web Modeling Language), an already established conceptual model for data-intensive Web applications, which is also accompanied by a development method and a CASE tool. However, given their general validity, the concepts of this article shape up a complete framework that can be adopted independently of the chosen model, method, and tool.