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An Illustration of New Methods in Machine Condition Monitoring, Part II: Adaptive outlier detection
No full textThere have been many recent developments in the application of data-based methods to machine condition monitoring. A powerful methodology based on machine learning has emerged, where diagnostics are based on a two-step procedure: extraction of damage-sensitive features, followed by unsupervised learning (novelty detection) or supervised learning (classification). The objective of the current pair of papers is simply to illustrate one state-of-the-art procedure for each step, using synthetic data representative of reality in terms of size and complexity. The second paper in the pair will deal with novelty detection. Although there has been considerable progress in the use of outlier analysis for novelty detection, most of the papers produced so far have suffered from the fact that simple algorithms break down if multiple outliers are present or if damage is already present in a training set. The objective of the current paper is to illustrate the use of phase-space thresholding; an algorithm which has the ability to detect multiple outliers inclusively in a data set
Production of menthol-loaded PCL nanoparticles by solvent displacement
No full textAbstract This Ph.D thesis focuses on the synthesis of menthol-loaded-Poly-ε-caprolactone nanoparticles (NP's) for transdermal application. Polymers are increasingly needed to produce nanoparticles ready to convey drugs to the tissues or cells of interest. Polymer nanoparticles are submicron-sized colloidal systems.Without doubt, the adequacy of these systems relies upon the structure of the vehicle and, specifically, on the mean size and on the particle size distribution (PSD). The poly-ε-caprolactone (PCL) polymer is chosen to synthesize nanoparticles because of its adaptability and fine tunning of its physico-chemical properties (great biocompatibility and biodegradability) which can be changed to acquire the desired nanoparticle size. Nanospheres have a monolithic type of structure (network) in which drugs are dispersed or absorbed on the surfaces or in the particles. Nano-capsules are vesicular systems in which the drug is kept in a cavity comprising of an inner liquid encompassed by a polymeric layer, which gives a supporting structure to the encapsulated material. For this state the active principle is normally dissolved in the inner core, yet may likewise be absorbed to the capsule surface. Nanosphere or nanocapsule development basically relies upon the production process. Nanoparticles utilized as drug delivery systems ought to be made out of biodegradable, biocompatible and nontoxic polymers. A number of distinctive strategies can be used to integrate polymer nanoparticles. Each has their own particular points of interest and constraints, which normally include blending of two fluid streams, e.g. emulsification-evaporation, emulsification-diffusion and solvent displacement. The solvent displacement strategy is characterized by simplicity of reproducibility, the possibility to utilize solvents with low poisonous potential and above all controlled particle size distribution (PSD). The nano-precipitation system involves dissolving the drug and polymer in the same solvent and afterward blending them with an antisolvent (typically water) in which the drug is immiscible and the nanoparticles are spontaneously framed. In this study, the nanoparticles were produced by utilizing three intensive reactors: a confined impinging jet mixer (CIJM), a two-inlet vortex mixer (VM) and a four-inlet vortex mixer (MIVM), testing their performance in the same operating conditions. Dynamic light scattering was carried out to measure the mean nanoparticle size (dp), particle size distribution (PSD), zeta potential (Z-average) and Polydispersity index (PDI). Nanoparticle separation was carried out by a centrifugation process for Transmission Electron microscope (TEM) analysis and menthol loading evaluation. Menthol quantification was evaluated by Gas chromatography (GC). Differential scanning calorimetry and transmission and scanning electron microscopy techniques were considered for analysing the particle surface morphology and menthol and identification in the nanoparticles and melatonin suspension over textile fabrics. Exceptional micro scale reactors are extremely helpful to get an efficient blend of the considerable number of components present in the solvent solution. High super-saturation can be produced by distinctive micromixers, for example, the Confined Impinging Jets Mixer (CIJM) and the Multi Inlet Vortex Mixer (MIVM), in less time than the required time for nucleation and growth procedures of the precipitating solutes. Super saturation brings the unconstrained development of nanoparticles within the nano estimate limits. The nanoparticles were prepared using the aforementioned intensive mixers (CIJM and MIVM), PCL polymer and diverse internal cores (menthol, melatonin, miglyol etc). The main goal was to investigate the effect of these working parameters on the mean size of the nanoparticles, a reasonable design of Experiment (DoE) was utilized. Furthermore, the effect of the inlet feed speed Vj (Flow rate FR), mass proportion and quench volumetric proportion QR (dilution) on the mean size dp , the zeta potential Zp and poly dispersity index (PDI) of the nanoparticles was also explored. At first poly-ε-caprolactone nanoparticles (nanospheres) were produced under different working conditions. The essential goal of this evaluation was to prepare the nanoparticle synthesis with a wide size range of menthol-loaded -PCL. A further aim to advance the synthesis parameters. After early promising results it was evident that further examinations were required keeping in mind the final goal to optimize the mean size of the nanoparticles. Likewise, quantification of nanoparticles was completed with the specific end goal of estimating drug loaded and encapsulation efficiency. Quantification procedure included various stages followed by centrifugation, extraction and gas chromatography analysis. All nanoparticles studied in this proposition were produced by the solvent displacement technique, utilizing three reactors CIJM, MIVM-4 and VM-2. All trials were performed with a PCL of monolithic-type molecular weight (Mw) 14000 g/mol. Two unique solvents were utilized for the production of the nanoparticles; acetone and acetonitrile. Since these solvents satisfy the following criteria: adequate dissolvability of PCL, water miscibility and low harmfulness. The impact of solvents on the delivered nanoparticles utilizing acetone and acetonitrile was seen: with higher estimations of the inlet feed rate, the nanoparticles became distinctly smaller. In addition, preliminary trials using a third solvent tehtrahydroforan were also done for the sake of comparsion. The impact of the working conditions on the mean size of nanoparticles was explored the underlying polymer concentration, the inlet feed rate and the impacts of the post preparing conditions, for example, the quench (dilution). It was found that the initial polymer concentration, and in addition the inlet feed velocity, has a significant impact on the mean size of nanoparticles. With higher feeding concentrations of PCL polymer, nanoparticles became distinctly greater. When feed velocity was expanded the mean size of nanoparticles diminished. It was also observed that NP size was higher for acetonitrile in contrast with acetone solvent at comparable working conditions in all cases. Moreover, dilution of the solution containing nanoparticles (higher the quench) was found indispensible to obtain stable nanoparticles. In addition, by expanding the inlet feed rate, smaller nanoparticles with lower zeta potential, were acquired. Smaller nanoparticles were created in the MIVM regarding the CIJM. Polydispersity index (PDI, 0.05 ± 0.3) and zeta potential (-30 mV to -40 mV) were observed in all investigated experiments. After nanoparticles were produced, they were quantified. An exact and appropriate measurement of menthol was acquired by a Gas chromatography (GC). Results showed that the incorporation efficiency of menthol in the nanoparticles with expanding menthol content was very nearly 60 % - 80 % in both the CIJM and VM mixers, and this indicates that menthol was adequately exemplified by PCL polymer upon precipitation. Loading was assessed at 35 % - 50 % around, with expanding mass proportion of menthol and PCL, when utilizing both reactors. These results were confirmed through morphologic perceptions of nanoparticles utilizing transmission electronic microscope (TEM) examination. From there on, the work was centered around the synthesis of PCL nanocapsules containing differing internal cores (miglyol, and melatonin). Melatonin nanocapsules were further utilized for the impregnation of cotton fabrics. Furthermore, the synthesis and characterization of the nanocapsules formed by PCL (surface layer) and by melatonin or miglyol (in the core) was investigated. To optimize the nanocapsules production process, the impact of different working conditions was explored i.e. the underlying polymer concentration, the underlying, melatonin or miglyol concentrations and the inlet feed rate, on their mean sizes. Comparative conclusions, were observed for menthol loaded nanoparticles, that is when expanding inlet feed rate the mean size of nanocapsules diminished. Finally, it was also found that when concentrations of all substances was increased larger nanocapsules were shaped
IL BIM PER LE SCUOLE. Analisi del patrimonio scolastico e strategie di intervento
No full textLa modellazione informativa si sta affermando come metodologia per la gestione integrata del processo edilizio e come supporto decisionale alle scelte strategiche e alla definizione delle priorità per la programmazione degli interventi per le grandi committenze. In questo volume si focalizza l'attenzione sullo stato attuale del patrimonio scolastico italiano e le politiche attive del MIUR per l'innovazione e la riqualificazione degli edifici esistenti. Vengono di seguito definiti i parametri prestazionali per la definizione della qualità degli spazi didattici e di socialità, anche in relazione alle nuove metodologie di apprendimento e alla didattica innovativa. Viene analizzata la struttura dell'anagrafica dell'edilizia scolastica utilizzata per censire il patrimonio, proponendo un sistema di digitalizzazione che permetta non solo di recuperare le informazioni inserite in termini di dati ma anche di archiviare lo storico e tutti gli interventi futuri, creando così un archivio digitale implementabile e costantemente aggiornato. Segue la presentazione della modellazione informativa con particolare attenzione ai vantaggi che ne può trarre la Committenza, nelle varie fasi del processo. Viene quindi presentato il BIM per la gestione del patrimonio scolastico esistente, supportato dal report di un caso di studio significativo. Il volume è destinato principalmente alle Committenze, private e pubbliche, ai gestori di patrimoni immobiliari, ai progettisti, consulenti e operatori del settore delle costruzioni, che intendono indagare la metodologia BIM intesa principalmente come innovazione di processo
Modelling and Analysis of Network Security Policies
No full textNowadays, computers and network communications have a pervasive presence in all our daily activities. Their correct configuration in terms of security is becoming more and more complex due to the growing number and variety of services present in a network. Generally, the security configuration of a computer network is dictated by specifying the policies of the security controls (e.g. firewall, VPN gateway) in the network. This implies that the specification of the network security policies is a crucial step to avoid errors in network configuration (e.g., blocking legitimate traffic, permitting unwanted traffic or sending insecure data). In the literature, an anomaly is an incorrect policy specification that an administrator may introduce in the network. In this thesis, we indicate as policy anomaly any conflict (e.g. two triggered policy rules enforcing contradictory actions), error (e.g. a policy cannot be enforced because it requires a cryptographic algorithm not supported by the security controls) or sub-optimization (e.g. redundant policies) that may arise in the policy specification phase. Security administrators, thus, have to face the hard job of correctly specifying the policies, which requires a high level of competence. Several studies have confirmed, in fact, that many security breaches and breakdowns are attributable to administrators' responsibilities. Several approaches have been proposed to analyze the presence of anomalies among policy rules, in order to enforce a correct security configuration. However, we have identified two limitations of such approaches. On one hand, current literature identifies only the anomalies among policies of a single security technology (i.e., IPsec, TLS), while a network is generally configured with many technologies. On the other hand, existing approaches work on a single policy type, also named domain (i.e., filtering, communication protection). Unfortunately, the complexity of real systems is not self-contained and each network security control may affect the behavior of other controls in the same network. The objective of this PhD work was to investigate novel approaches for modelling security policies and their anomalies, and formal techniques of anomaly analysis. We present in this dissertation our contributions to the current policy analysis state of the art and the achieved results. A first contribution was the definition of a new class of policy anomalies, i.e. the inter-technology anomalies, which arises in a set of policies of multiple security technologies. We provided also a formal model able to detect these new types of anomalies. One of the results achieved by applying the inter-technology analysis to the communication protection policies was to categorize twelve new types of anomalies. The second result of this activity was derived from an empirical assessment that proved the practical significance of detecting such new anomalies. The second contribution of this thesis was the definition of a newly-defined type of policy analysis, named inter-domain analysis, which identifies any anomaly that may arise among different policy domains. We improved the state of the art by proposing a possible model to detect the inter-domain anomalies, which is a generalization of the aforementioned inter-technology model. In particular, we defined the Unified Model for Policy Analysis (UMPA) to perform the inter-domain analysis by extending the analysis model applied for a single policy domain to comprehensive analysis of anomalies among many policy domains. The result of this last part of our dissertation was to improve the effectiveness of the analysis process. Thanks to the inter-domain analysis, indeed, administrators can detect in a simple and customizable way a greater set of anomalies than the sets they could detect by running individually any other model
Verification and Configuration of Software-based Networks
No full textThe innovative trends of Network Function Virtualization (NFV) and Software Defined Networking (SDN) have posed never experienced opportunities in productive environments, like data centers. While NFV decouples software implementation of the network functions (e.g., DPI and NAT) from their physical counterparts, SDN is in charge of dynamically changing those functions to create network paths. One new opportunity of such Software-based networks is to make the network service-provisioning models more flexible, by enabling users to build their own service graphs: users can select the Virtual Network Functions (VNFs) to use and can specify how packets have to be processed and forwarded in their networks. In particular, this PhD thesis spans mostly topics related to the verification and configuration of service graphs. For what concerns the challenges of network verification, our aim is to explore strategies that overcome the limitations of traditional techniques, which generally exploit complex modelling approaches and takes considerable verification times. Thus we envision for verification techniques that are based on non-complex modelling approaches in order to be much more efficient than existing proposals. Under these conditions, such novel approaches may work at run-time and, in particular, may be performed before deploying the service graphs, in order to avoid unexpected network behaviours and detect errors as early as possible. Another requirement is that verification should take a reasonable amount of time from a VNF Orchestrator point of view, with fair processing resources (e.g. CPU, memory and so on). This is because we are in the context of flexible services, where the reconfiguration of network functions can be frequently triggered, both in case of user request and in case of management events. The first contribution of this thesis lays on the service graphs specification by means of forwarding policies (i.e, a high-level specification of how packet flows are forwarded). While the majority of the SDN verification tools operate on OpenFlow configurations, we have defined a formal model to detect a set of anomalies in forwarding policies (i.e., erroneous specifications that may cause misleading network conditions and states). The key factors that distinguish our work from existing approaches are both an early detection of policies anomalies (i.e., before translating such policies into OpenFlow entries), in order to speed up the fixing phase, without even starting service deployment, and a scalable approach that achieves verification times in the order of milliseconds for medium- large- sized networks. Another advancement in network verification has been the possibility to verify networks including stateful VNFs, which are functions that may dynamically change the forwarding path of a traffic flow according to their local algorithms and states (e.g., IDSs). Our second contribution is thus a verification approach that models the network and the involved (possibly stateful) VNFs as a set of FOL formulas. Those formulas are passed to the off-the-shelf SMT (Satisfiability Modulo Theory) solver Z3 in order to verify some reachability-based properties. In particular, the proposed solution has been implemented in a tool released under the AGPLv3 license, named VeriGraph, which takes the functional configurations of all deployed VNFs (e.g., filtering rules on firewalls) into account to check the network. The adopted approach achieves verification times in the order of milliseconds, which is compliant with the timing limitations needed by a VNF Orchestrator. Finally, for what concerns the configuration of VNFs, service graph deployment should include a strategy to deploy VNF configurations in order to fix bugs in case of verification failures. Here, we have to face several challenges like the different ways a network function may require for being configured (REST API, CLI, etc...) and the configuration semantic that depends on the function itself (e.g., router parameters are clearly different from firewall ones). We conclude this thesis by proposing a model-based configuration approach, which means defining a representation of the main configuration parameters of a VNF. This VNF model is then automatically processed by further software modules in the VNF architecture to translate the configuration parameters into a particular format required by a VNF and to deliver the produced configuration into the VNF following one of the configuration strategies (e.g., REST, configuration file, etc.) already supported by the function. The achieved results of this last work, w.r.t. the current state of the art, are the exploitation of a model-driven approach that achieves a higher flexibility and the insertion of non-VNF-specific software modules to avoid changes in the VNF implementation
Lean construction applied to a BIM process: how to control point attribution in MEAT tender process
No full textLean Construction (LC) and Building Information Modelling are the two methodologies linked by the same objectives. The former is an industrial optimization, which want to achieve the aim of performance increasing with the application to the AEC industry. These two concepts leaded Melzo school tender process writing. There are huge differences from a traditional process approach compared with BIM one, which leads project to a coherence high level. A deep LC principles understanding entail a distribution of the point to the different categories. The importance of LC criteria, in terms of points, imposes to the companies a change in the mind-set, from a lowest bid approach to a performance one. The study is based on the analysis of the responses to the case study procurement. Different competitors answer differently in function of Lean principles weight and their knowledge. The change in the state of mind leads the companies to offers value. In some cases, even if, many points were not able to change their behaviour. The behaviour' modification will be a difficult transformation for the AEC sector
Acqua, turismo, architettura
No full textNote su gli edifici termali nel Piemonte sud- occidentale con riferimento particolare alla Valle Stura, dall'Ottocento ai progetti contemporanei sino agli scenari per uno sviluppo sostenibile intorno al tema dell'acqua
Energy Consumption in an Italian Opera House: Analysis and Possible Reduction
No full textThe refurbishment of historic buildings is a complex task where the goal of obtaining a more energy efficient building often conflicts with the peculiar characteristics of the built environment, and its final destination. In this paper, the authors address this problem for a very specific type of building: a historic opera house located in Northern Italy. The results of energy consumption monitoring and spot measurements on selected loads are herein used as a basis to propose energy saving strategies
An asymptotic approach to the crenulation instability
No full textA novel linear stability analysis for the pattern formation of ripple-like corrugations, over the surface of stalactites due to calcite-laden falling films, is presented by using a modified version of the gradient expansion technique. A fully analytical theory combining thin film hydrodynamics, Kármán-Pohlhausen solution of the advection-diffusion equation for calcium concentration and an evolution equation for the shape of the liquid-solid interface is developed. Analytical formulas for the selected wavelength and the corresponding phase velocity are provided, which match previous numerical solutions. The obtained easy-to-use mathematical results have a potential for developing a novel set of paleo-reconstruction proxies based on the link between morphological patterns and paleo-flows