371 research outputs found

    Towards the Control of Electrophotographic-based 3-Dimensional Printing: Image-Based Sensing and Modeling of Surface Defects

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    Electro-Photography (EP) has been used for decades for fast, cheap, and reliable printing in offices and homes around the world. It has been shown that extending the use of EP for 3D printing is feasible; multiple layered prints are already commercially available (color laser printers) but only for a very limited number of layers. Many of the advantages of laser printing make EP 3D printing desirable including: speed, reliability, selective coloring, ability to print a thermoplastic, possibilities for multi-material printing, ability to print materials not amenable to liquid ink formulations. However, many challenges remain before EP-based 3D printing can be commercially viable. A limiting factor in using the same system architecture as a traditional laser printer is that as the thickness of the part increases, material deposition becomes more difficult with each layer since the increased thickness reduces the field strength. Different system configurations have been proposed where the layer is printed on intermediate stations and are subsequently transferred to the work piece. Layer registration and uniform transfer from the intermediate station become crucial factors in this architecture. At the Print Research and Imaging Systems Modeling (PRISM) Lab preliminary tests have confirmed the feasibility of using EP for Additive Manufacturing (AM). However, similar issues were encountered to those reported in literature as the number of layers increased, resulting in non-uniform brittle 3D structures. The defects were present but not obvious at each layer, and as the part built up, the defects add up and became more obvious. The process, as in many printers, did not include a control system for the ultimate system output (print), and the actuation method (electrostatic charge) is not entirely well characterized or sensed to be used in a control system. This research intends to help the development of a model and an image-based sensing system that can be used for control of material deposition defects for an EP 3D printing process. This research leverages from the expertise at RIT and the Rochester area in Printing, Electrophotography, Rapid Prototyping, Control, and Imaging Sciences

    Аграрне перенаселення в українських губерніях Російської імперії початку ХХ ст.

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    Sustainable urban development is a critical issue in the Netherlands. The country is densely populated, which causes conflicts between environmental concerns and spatial development. Environmental policy integration is proposed as a way to improve the integration of environmental values into spatial planning with the help of learning processes. This chapter evaluates the extent to which the combination of a map-based touch table and an area-specific environmental profile are of added value to environmental policy integration. The case study is the application of the map-based touch table, called MapTable® for the development of a sustainable neighborhood in the region of Utrecht, the Netherlands. It was found that MapTable® facilitates learning processes by providing a platform for communication among stakeholders from different backgrounds. Nonetheless, it must be ensured that all stakeholders are equally included, and that the process suits the application of a map-based touch table in combination with an area-specific environmental profile

    Is schizoaffective disorder a distinct categorical diagnosis? A critical review of the literature

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    Considerable debate surrounds the inclusion of schizoaffective disorder in psychiatric nosology. Schizoaffective disorder may be a variant of schizophrenia in which mood symptoms are unusually prominent but not unusual in type. This condition may instead reflect a severe form of either major depressive or bipolar disorder in which episode-related psychotic symptoms fail to remit completely between mood episodes. Alternatively, schizoaffective disorder may reflect the co-occurrence of two relatively common psychiatric illnesses, schizophrenia and a mood disorder (major depressive or bipolar disorder). Each of these formulations of schizoaffective disorder presents nosological challenges because the signs and symptoms of this condition cross conventional categorical diagnostic boundaries between psychotic disorders and mood disorders. The study, evaluation, and treatment of persons presently diagnosed with schizoaffective may be more usefully informed by a dimensional approach. It is in this context that this article reviews and contrasts the categorical and dimensional approaches to its description, neurobiology, and treatment. Based on this review, an argument for the study and treatment of this condition using a dimensional approach is offered

    Optimization of a new Ni-free Ti alloy for applications in the implant field

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    Three new Ni-free Ti alloys, Ti-16.2Hf-24.8Nb-1Zr, Ti-5.2Hf-31.2Nb-0.4Zr and Ti-16Hf-36.2Nb-1Zr (wt%), were designed and produced in order to obtain shape memory and/or low elastic modulus materials in order to avoid stress shielding and to enhance bone regeneration in the load transfer implant field. The alloys were microstructurally and mechanically characterized, cytotoxicity was evaluated using MG63 osteoblast-like cells. The elastic modulus of the new alloys (between 67-90 GPa) are smaller than those of the commercial alloys employed for implantation. The lowest elastic modulus alloy, Ti-16.2Hf-24.8Nb-1Zr (wt %), with 67.5 GPa, was optimized by cold work in order to determine the key factor that promotes the desired shape memory properties and/or low elastic modulus. A higher proportion of martensite was observed by optical and electron transmission microscopy in the low cold work samples compared to the quenched alloy. The elastic modulus for each cold work condition was evaluated by nanoindentation tests using a spherical tip. The elastic modulus decreases when increasing the cold work level. The lowest value corresponds to the 99% cold work condition, with 44 GPa, closer to that of cortical bone and smaller than the quenched alloy (67.5 GPa).Tres nuevas aleaciones de Ti libres de Ni, Ti-16.2Hf-24.8Nb-1Zr, Ti-5.2Hf-31.2Nb-0.4Zr y Ti-16Hf-36.2Nb-1Zr, porcentajes en peso, fueron diseñadas y fabricadas con el fin de obtener memoria de forma y/o bajo módulo elástico con el objetivo de evitar el apantallamiento de cargas y mejorar la regeneración ósea en el campo de la implantología de transferencia de carga. Las aleaciones fueron caracterizadas microestructural y mecánicamente y la citotoxicidad fue evaluada utilizando osteoblastos MG63. El módulo elástico de las nuevas aleaciones (entre 67-90 GPa) es menor que el de las aleaciones comerciales utilizadas en implantología. El menor módulo elástico corresponde a la aleación Ti-16.2Hf-24.8Nb-1Zr, con 67.5 GPa y fue optimizado mediante trabajo en frío con el objetivo de determinar el factor responsable de la obtención de las propiedades deseadas de bajo módulo elástico y/o memoria de forma. Una mayor proporción de martensita fue observada por microscopía óptica y microscopía electrónica de transmisión en las muestras con bajo porcentaje de trabajo en frío en comparación con la muestra templada. El módulo elástico correspondiente a cada condición de trabajo en frío fue evaluado mediante nanoindentación con punta esférica. El módulo elástico disminuye al aumentar el porcentaje de trabajo en frío. El menor valor corresponde a la condición de 95% de trabajo en frío, con 44 GPa, valor cercano al del hueso cortical y menor que el del material templado (67.5 GPa).Peer Reviewe

    Modelo arquitectónico desde la vista de información para apoyar la interoperabilidad de herramientas software que soportan la mejora de procesos de software

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    (Eng) Diverse software tools that support the software process improvement (SPI) not interoperate between them, that is to say, the exchange of information between the different tools is deficient, making it difficult to sequence and automatic re-use of information of SPI initiatives. In this article we present an architectural model from the information view to support the interoperability of software tools that support the stages of diagnosing the process and formulating improvements. The model establishes architecture that describes the type of information that can be exchanged these tools, as well as the structure of the data, their possible values, its semantics, and the restrictions imposed on the use and interpretation of such information. The architectural model is composed of a set of schemas, raised in conceptual form, which can be used by organizations that wish to develop software tools to interoperate, which provide support in a comprehensive way to diagnosing the process and formulating improvements of the SPI cycle. These schemas were evaluated using the qualitative method Focus Group.(Spa) La gran mayoría de herramientas software que soportan la mejora de procesos de software (SPI) no interoperan entre ellas, es decir, el intercambio de información entre las diferentes herramientas es deficiente, lo que dificulta la secuencia y reutilización automática de la información de las iniciativas de SPI. En este artículo presentamos un modelo arquitectónico desde la vista de información para apoyar la interoperabilidad de las herramientas software que soportan las etapas de Diagnóstico de procesos y Formulación de mejoras. El modelo establece la arquitectura que describe el tipo de información que pueden intercambiar estas herramientas, así como la estructura de los datos, sus posibles valores, su semántica, y las restricciones impuestas sobre la utilización e interpretación de dicha información. El modelo arquitectónico está constituido por un conjunto de esquemas planteados de forma conceptual, el cual puede ser utilizado por organizaciones que deseen desarrollar herramientas software que interoperen entre sí, las cuales brinden soporte de manera integral al Diagnóstico y Formulación del ciclo de SPI. Estos esquemas fueron evaluados utilizando el método cualitativo Focus Group

    Neural Networks for Text-to-Speech Phoneme Recognition

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    Abstract This paper presents two different artificial neural network approaches for phoneme recognition for text-to-speech applications: Staged Backpropagation Neural Networks and SelfOrganizing Maps. Several current commercial approaches rely on an exhaustive dictionary approach for text-to-phoneme conversion. Applying neural networks for phoneme mapping for text-to-speech conversion creates a fast distributed recognition engine. This engine not only supports the mapping of missing words on the database, but it can also mitigate contradictions related to different pronunciations for the same word. The ANNs presented in this work were trained based on the 2000 most common words in American English. Performance metrics for the 5000, 7000 and 10000 most common words in English were also estimated to test the robustness of these neural networks

    Map-based multicriteria analysis to support interactive land use allocation

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    This article focuses on the use of map-based multicriteria analysis to develop a negotiation support tool for land use allocation. Spatial multicriteria analysis is used to make explicit trade-offs between objectives and to provide guidance and feedback on the land use changes negotiated by the participants. Digital maps are the means of communication among workshop participants, and an interactive mapping device (the 'Touch table') is used as the interface. Participants are informed about the relevant trade-offs on the map and use this information to change the land use maps. The approach is tested during a negotiation session as part of the land use planning process of the Bodegraven polder, a peat meadow area in the Netherlands. © 2011 Copyright Taylor and Francis Group, LLC

    Value of early postoperative epicardial programmed ventricular stimulation studies after surgery for ventricular tachyarrhythmias

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    The value of early postoperative epicardial programmed ventricular stimulation studies after electrophysiologically-directed surgery for ventricular tachyarrhythmia was assessed in 34 patients who underwent epicardial stimulation within 7 to 30 days (mean 9.8) of surgery and were followed up for at least 6 months. The antiarrhythmic operation performed was an endocardial ventriculotomy (full encircling or limited), an endocardial resection, a wall resection or a combination of these procedures. All these interventions were directed by intraoperative mapping during sinus rhythm. Temporary epicardial wire electrodes left at the time of surgery rather than endocardial catheter electrodes were used to perform the pacing. The stimulation protocol included the introduction of up to three ventricular extrastimuli and incremental burst ventricular pacing performed at twice diastolic threshold (9.2 ± 5.8 mA for the right ventricle and 6.0 ± 3.5 mA for the left ventricle). A study was considered positive when ventricular tachycardia, defined as 10 or more consecutive ventricular beats, was induced by any pacing modality.Nineteen patients (Group I) had a negative study: after stimulation of both ventricles in 15 patients and of the left ventricle only in 4. Fifteen patients (Group II) had a positive study: after stimulation of the right ventricle in nine patients and of the left ventricle in six. The two groups were comparable with respect to preoperative clinical status, surgical procedures performed and postoperative ejection fraction. No arrhythmic events were observed in Group I during a mean follow-up period of 19.5 months (range 4 to 37), whereas seven arrhythmic events (47% incidence) occurred (p = 0.0008) in Group II during a mean follow-up period of 17.7 months (range 5 to 39). These arrhythmic events were sudden death (five patients) and sustained ventricular tachycardia (two patients).It is concluded that temporary epicardially-placed electrodes can be used satisfactorily to perform programmed ventricular stimulation studies in the postoperative period, thereby avoiding the cardiac catheterizations otherwise necessary to perform these studies. In addition, the protocol used in this report of epicardial programmed ventricular stimulation early after surgery for ventricular tachyarrhythmia predicts a good outcome if the study is negative and identifies patients at a high risk for future arrhythmic events when positive

    Designing the Didactic Strategy Modeling Language (DSML) From PoN: An Activity Oriented EML Proposal

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    [EN] This paper presents the design of the didactic strategy modeling language (DSML) according to the principles of Physics of Notations (PoN). The DSML is a visual and activity-oriented language for learning design characterized by the representation of different activities according to the nature of the task. Once the language is designed, a blind interpretation study is conducted to validate the semantic transparency of the learning activity iconography. The results of the paper allow to refine the icons. In addition to this, an authoring tool for DSML, which is integrated to an LMS, is presented. As a result, a model driven course was designed as a DSML pre-validation.Ruiz, A.; Panach Navarrete, JI.; Pastor López, O.; Giraldo-Velásquez, FD.; Arciniegas, JL.; Giraldo, WJ. (2018). Designing the Didactic Strategy Modeling Language (DSML) From PoN: An Activity Oriented EML Proposal. IEEE-RITA: Latin-American Learning Technologies Journal. 13(4):136-143. https://doi.org/10.1109/RITA.2018.2879262S13614313

    Delusions in frontotemporal lobar degeneration

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    We assessed the significance and nature of delusions in frontotemporal lobar degeneration (FTLD), an important cause of young-onset dementia with prominent neuropsychiatric features that remain incompletely characterised. The case notes of all patients meeting diagnostic criteria for FTLD attending a tertiary level cognitive disorders clinic over a three year period were retrospectively reviewed and eight patients with a history of delusions were identified. All patients underwent detailed clinical and neuropsychological evaluation and brain MRI. The diagnosis was confirmed pathologically in two cases. The estimated prevalence of delusions was 14 %. Delusions were an early, prominent and persistent feature. They were phenomenologically diverse; however paranoid and somatic delusions were prominent. Behavioural variant FTLD was the most frequently associated clinical subtype and cerebral atrophy was bilateral or predominantly right-sided in most cases. We conclude that delusions may be a clinical issue in FTLD, and this should be explored further in future work
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