186,581 research outputs found
Managing information constraints over networks through the lens of configuration functions
No full textThis work deals with networks of agents that exchange information under communication constraints. As a first contribution, the theory of configuration functions is exploited to obtain a general abstract formulation of the network information as a function of the network constraints. As a second contribution, two classic network paradigms are examined: i) a decentralized architecture with remote fusion center; and ii) a fully-flat decentralized architecture with local data exchange between neighboring agents. It is shown how these paradigms match well with the general formulation in terms of configuration functions. Finally, the statistical concentration properties of configuration functions are exploited to characterize the information growth rate under both the aforementioned network paradigms, revealing the thermodynamic deterministic behavior that emerges with high probability as the network size scales to infinity
An unexpected adverse event of gastric bypass: giant hyperplastic polyp showing an intramucosal adenocarcinoma
No full textAn improved version of the generalized Laplacian pyramid algorithm for pansharpening
No full textThe spatial resolution of multispectral data can be synthetically improved by exploiting the spatial content of a companion panchromatic image. This process, named pansharpening, is widely employed by data providers to augment the quality of images made available for many applications. The huge demand requires the utilization of efficient fusion algorithms that do not require specific training phases, but rather exploit physical considerations to combine the available data. For this reason, classical model-based approaches are still widely used in practice. We created and assessed a method for improving a widespread approach, based on the generalized Laplacian pyramid decomposition, by combining two different cost-effective upgrades: the estimation of the detail-extraction filter from data and the utilization of an improved injection scheme based on multilinear regression. The proposed method was compared with several existing efficient pansharpening algorithms, employing the most credited performance evaluation protocols. The capability of achieving optimal results in very different scenarios was demonstrated by employing data acquired by the IKONOS and WorldView-3 satellites
Editorial for Special Issue "Remote Sensing for Target Object Detection and Identification"
No full textThis special issue gathers fourteen papers focused on the application of a variety of target object detection and identification techniques for remotely-sensed data. These data are acquired by different types of sensors (both passive and active) and are located on various platforms, ranging from satellites to unmanned aerial vehicles. This editorial provides an overview of the contributed papers, briefly presenting the technologies and algorithms employed as well as the related applications
Broadband reflectors with a disordered layered structure: statistical properties of high performing configurations selected via genetic algorithm
No full textDisordered multilayers consisting of alternating layers of two lossless dielectric materials with random thicknesses can behave as good reflectors in wide wavelength ranges except for narrow bands where the transmittance is significative. We use a dedicated genetic algorithm to select different configurations (thickness sequences) of such structures which exhibit very low transmittance in the entire visible wavelength range, showing that broadband disordered reflectors with very high performance can be designed. A statistical analysis of the thickness sequences selected by the genetic algorithm reveals that such sequences are characterized by correlated disorder and that the degree of autocorrelation is a key parameter in determining the reflection performance
Prostatic stromal sarcoma: Report of a rare case in a young male and review of the literature
No full textIntroduction and importance: Common prostatic neoplasms are diagnosed frequently, whereas rare entities require particular awareness and special clinical management. Case presentation: A 31-year-old man presented with dysuria, hematuria and urinary retention. Histomorphological analysis of material obtained by transurethral resection of the prostate initially favored a sarcomatoid carcinoma, but immunohistochemistry allowed the correct diagnosis of sarcoma of the specialized stroma of the prostate. Clinical discussion: The patient refused surgical treatment and, despite chemotherapy, he died 8 months after the diagnosis. Herein, we will highlight the diagnostic and therapeutic challenge of prostatic stromal sarcoma by illustrating this case and reviewing the relevant literature. Conclusion: Although rare and shadowed by more common neoplasms that may mimic it, prostatic stromal sarcoma should be considered in the differential diagnosis of bladder and prostate neoplasms because of its dismal prognosis
Escape time characterization of pendular Fabry-Perot
No full textIn a pendular Fabry-Perot interferometer the system placed inside one of the minimum of the optomechanical potential undergoes an escape if it crosses the point of sudden change of reflectivity near the top of the potential well. We demonstrate that the loss of information that occurs retaining only the sequence of escapes, rather than the full trajectory, is mild if suitable signal processing techniques are applied to reveal the noise intensity or the presence of a coherent signal
ADVoIP: Adversarial Detection of Encrypted and Concealed VoIP
No full textA network attacker wants to transmit Voice-over-IP (VoIP) traffic streams covertly. He tries to evade the detection system by manipulating the VoIP streams through padding, shifting, and splitting operations, so as to conceal them amidst the Internet traffic. A defender wants to detect the manipulated VoIP streams. Tackling this problem from an adversarial perspective, we provide two contributions: 1) we obtain a highly stylized representation of VoIP streams in terms of transmission frequency F and packet length L , and characterize the F, L region achievable by the attacker's transformation and 2) We formulate the VoIP detection game, and find both theoretical conditions and a practical algorithm to find the Nash equilibrium of the game. As a result, we are able to design an optimal (from the adversarial perspective) algorithm for VoIP detection, which is nicknamed as ADVoIP. Simulations over real network traces, and comparison with existing approaches, show the effectiveness of the proposed approach
A Data-Driven Model-Based Regression Applied to Panchromatic Sharpening
No full textImage fusion is growing interest in recent years, thanks to the huge amount of data acquired everyday by sensors on board of satellite platforms. The enhancement of the spatial resolution of a multispectral (MS) image through the use of a panchromatic (PAN) image, usually called pansharpening, is getting more and more relevant. In this work, we focus on the problem of the estimation of the injection coefficients that rule the enhancement of the spatial resolution of the MS image by properly adding the PAN details. In particular, a statistical analysis of the residuals coming from the linear multivariate regression between details extracted from the PAN image and the MS image is performed. A novel hybrid model is introduced for accurately describing the statistical distribution of these residuals, together with a procedure for efficiently estimating both the parameters of the residual distribution and the injection coefficients. The improvements achieved by the proposed approach are assessed using two very high resolution datasets acquired by the WorldView-3 and Worldview-4 satellites. The benefits of the proposed approach are particularly clear when vegetated areas are involved in the fusion process
Cellular neurothekeoma with neuroendocrine differentiation
No full textWe report a case of cellular neurothekeoma with unusual clinicopathological features in which neuroendocrine markers, determined by immunohistochemistry were observed. Histologically, the tumor showed a micronodular architecture with hypercellular lobules composed of slightly spindled to epithelioid cells, with nuclear atypia or pleomorphism and extension into fat, skeletal muscle. Neoplastic cells were immunoreactive for NKI/C3, CD68, CD10, and smooth-muscle actin, whereas S100 and HMB-45 staining was negative. An intriguing feature was the strong expression by tumor cells of different neuroendocrine markers. Clinical follow up showed no local recurrences after five months despite the presence of positive margins. The presence of atypical histopathological features may cause diagnostic problems with malignant mesenchymal tumors, nevo-melanocytic lesions, and fibrohistiocytic tumors. The immunohistochemical profile including the positive staining for neuroendocrine markers may suggest divergent differentiation or an origin from myofibroblast and neuroendocrine cells. © 2011 Dermatology Online Journal
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