Unspecified Component Research Articles

Mathematical modeling of fluid flows through the piecewise homogeneous porous medium by R-function method

The stationary fluid flow through a piecewise homogeneous porous medium is considered under the assumption that Darcy's law holds. The mathematical model of this problem is defined as an elliptic equation for the stream function, supplemented by the second-type boundary conditions at the water boundaries and the first-type boundary conditions at the impervious to liquid boundaries. The problem statement also includes the conditions of conjugation at the separation line between two soils and the unknown value of fluid discharge, which can be established from the additional integral ratio. It is proposed to use the structure-variational method of R-functions in order to numerically analyze and solve the current problem. The complete solution structure for the boundary value problem of stream function regarding the R-functions method is established, moreover, the application of the Ritz method for approximating an unspecified structural formula component is substantiated. Then, the approximate value of the fluid discharge and the approximate solution of the original problem are found from the additional integral ratio. The computational experiment was carried out with different coefficients of permeability within the area, which has the shape of the lower half ring. It is established that as the number of coordinate functions increases, the value of fluid discharge becomes constant, indicating the convergence of the proposed method.

Abstract 2091: DeepBTS: Prediction of recurrence-free survival of non-small cell lung cancer using time-binned deep neural network

Abstract Introduction: Accurate prediction of non-small cell lung cancer (NSCLC) prognosis after surgery is still challenging. Cox proportional hazard model is widely used, but there are some limitations like proportional hazard assumption, computational complexity, and unspecified time component. In this study, we developed the novel neural network models using 30 clinicopathological features of surgically resected NSCLC patients. Materials and Methods: We analyzed a dataset of training cohorts of 1,034 patients and external validation cohort of 303 patients, and compared the novel neural network model and Cox PH model to predict 3-year recurrence of the patient. Results: We developed deep neural network for binned time survival analysis (DeepBTS) algorithm, which use root-mean-squared error (supervised learning model, s- DeepBTS) or negative log-likelihood (semi-unsupervised learning model, su- DeepBTS) as loss function. The su-DeepBTS algorithm showed the improved performance (C-index, 0.7166; AUC, 0.7606) compared to other models (Cox PH: 0.6861 and 0.7185; s-DeepBTS: 0.6926 and 0.7250, respectively). Top 10 features was selected from su-DeepBTS model and su-DeepBTS selector pair: the number of lymph node metastasis, tumor size, histologic subtype, vascular invasion, R0 resection, neoadjuvant /adjuvant treatment, and performance status of patients. These features distinguished low and high-risk group in the training cohort (p = 4.25×10-5) and the validation cohort (p = 1.07×10-11). Conclusions: The su-DeepBTS model using 10 selected features can predict the prognosis of resected NSCLC patients. We plan to diversify the input features by radiologic, pathological imaging and genomic data to integrate multimodal medical information and enhance the performance of this model using deep neural network. Citation Format: Ho Jung An, Bora Lee, Sang Hoon Chun, Ji Hyung Hong, In Sook Woo, Seoree Kim, Joon Won Jeong, Jae Jun Kim, Hyun Woo Lee, Sungsoo Park, Heejoon Jo, Yoon Ho Ko. DeepBTS: Prediction of recurrence-free survival of non-small cell lung cancer using time-binned deep neural network [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2091.

Urethral atrophy is now a rare cause for artificial urinary sphincter revision surgery in the contemporary 3.5 cm cuff era.

Urethral atrophy has long been suggested as the leading cause of artificial urinary sphincter (AUS) revision. Since the introduction of the 3.5 cm AUS cuff in 2010, precise cuff sizing primarily has been suggested to reduce revisions due to urethral atrophy. We evaluated a large contemporary series of reoperative AUS cases to determine reasons for revision surgery. We retrospectively reviewed our tertiary referral center database of male AUS procedures performed by a single surgeon from 2007-2019. AUS revision or replacement procedures were included for analysis. Cuff sizes and reasons for reoperation were recorded based on intraoperative findings and evaluated for temporal trends. Patients with cuff erosion or lacking follow-up were excluded. Among 714 AUS cases, 177 revisions or replacements were identified. Of these, 137 met inclusion criteria [mean age 71.7 years, median follow-up 52.7 months (IQR 22.3-94.6 months)]. Urethral atrophy was cited as the cause of AUS failure in 8.0% (11/137) of cases overall, virtually never among those with a 3.5 cm cuff placement (1/51, 2.0%). In those with ≥4.0 cm cuffs, urethral atrophy was the reason for revision in 10/86 (11.6%). Pressure regulating balloon (PRB) failure was the most frequently cited cause of failure (47/137, 34.3%). Cuff-related failure (23/137, 16.8%) and mechanical failure of unspecified device component (16/137, 11.8%) were the next most frequent causes of failure. Urethral atrophy has become a rare cause of AUS revision surgery since the availability of smaller cuffs. PRB-related failure is now the leading cause of AUS reoperation.

Trace element systematics and Nd, Sr and Pb isotopes of Pliocene flood basalt magmas (Ethiopian rift): A case for Afar plume-lithosphere interaction

We present high-precision trace element and Sr-Nd-Pb isotope data for Pliocene flood basalts located at Sire (eastern rift wall) and Chefe Donsa (western rift wall) sections from the main Ethiopian rift (MER). These basalts are tholeiitic to mildly alkaline and were derived by moderate degrees of melting (~10–20%) of a spinel lherzolite containing minor amounts of amphibole within the lithospheric mantle. Strontium, Nd and Pb isotopic compositions (87Sr/86Sr: 0.7040–0.7057, 143Nd/144Nd: 0.52164–0.51287, 206Pb/204Pb: 17.75–19.20, 207Pb/204Pb: 15.53–15.64 and 208Pb/204Pb: 38.12–38.86) are between the inferred composition of the Afar mantle plume and an unspecified enriched lithospheric component, suggesting interaction of melts from asthenospheric and lithospheric mantle domains rather than melting of homogeneous mixed sources or magma mixing. It is proposed that in the Oligocene the impinging Afar plume creates zones of metasomatically enriched mantle. Later, lithospheric thinning as a result of incipient rifting leads to decompression and melting of this metasomatically enriched mantle due to its lower solidus temperature. The chemistry of the Pliocene lavas therefore reflect two associated scenarios namely (i) upwelling plume material from the advancing Afar plume may have induced metasomatism in the lithospheric mantle (ii) mobilization and melting of this enriched lithospheric mantle material resulted in melts characterized by variable mixtures of the two mantle reservoirs.

Verification of asynchronous systems with an unspecified component

Component-based systems evolve as a new component is added or an existing one is replaced by a newer version. Hence, it is appealing to assure the new system still preserves its safety properties. However, instead of inspecting the new system as a whole, which may result in a large state space, it is beneficial to reuse the verification results by inspecting the newly added component in isolation. To this aim, we study the problem of model checking component-based asynchronously communicating systems in the presence of an unspecified component against safety properties. Our solution is based on assume-guarantee reasoning, adopted for asynchronous environments, which generates the weakest assumption. If the newly added component conforms to the assumption, then the whole system still satisfies the property. To make the approach efficient and convergent, we produce an overapproximated interface of the missing component and by its composition with the rest of the system components, we achieve an overapproximated specification of the system, from which we remove those traces of the system that violate the property and generate an assumption for the missing component. We have implemented our approach on two case studies. Furthermore, we compared our results with the state of the art direct approach. Our resulting assumptions are smaller in size and achieved faster.

Kinetic approach to condensation: Diatomic gases with dipolar molecules.

We derive a kinetic equation for rarefied diatomic gases whose molecules have a permanent dipole moment. Estimating typical parameters of such gases, we show that quantum effects cannot be neglected when describing the rotation of molecules, which we thus approximate by quantum rotators. The intermolecular potential is assumed to involve an unspecified short-range repulsive component and a long-range dipole-dipole Coulomb interaction. In the kinetic equation derived, the former and the latter give rise, respectively, to the collision integral and a self-consistent electric field generated collectively by the dipoles (as in the Vlasov model of plasma). It turns out that the characteristic period of the molecules' rotation is much shorter than the time scale of the collective electric force and the latter is much shorter than the time scale of the collision integral, which allows us to average the kinetic equation over rotation. In the averaged model, collisions and interaction with the collective field affect only those rotational levels of the molecules that satisfy certain conditions of synchronism. It is then shown that the derived model does not describe condensation; i.e., permanent dipoles of molecules cannot exert the level of intermolecular attraction necessary for condensation. It is argued that an adequate model of condensation must include the temporary dipoles that molecules induce on each other during interaction, and that this model must be quantum, not classical.

R-Estimation for Asymmetric Independent Component Analysis

Independent component analysis (ICA) recently has attracted much attention in the statistical literature as an appealing alternative to elliptical models. Whereas k-dimensional elliptical densities depend on one single unspecified radial density, however, k-dimensional independent component distributions involve k unspecified component densities. In practice, for given sample size n and dimension k, this makes the statistical analysis much harder. We focus here on the estimation, from an independent sample, of the mixing/demixing matrix of the model. Traditional methods (FOBI, Kernel-ICA, FastICA) mainly originate from the engineering literature. Their consistency requires moment conditions, they are poorly robust, and do not achieve any type of asymptotic efficiency. When based on robust scatter matrices, the two-scatter methods developed by Oja, Sirkia, and Eriksson in 2006 and Nordhausen, Oja, and Ollila in 2008 enjoy better robustness features, but their optimality properties remain unclear. The “classical semiparametric” approach by Chen and Bickel in 2006, quite on the contrary, achieves semiparametric efficiency, but requires the estimation of the densities of the k unobserved independent components. As a reaction, an efficient (signed-)rank-based approach was proposed by Ilmonen and Paindaveine in 2011 for the case of symmetric component densities. The performance of their estimators is quite good, but they unfortunately fail to be root-n consistent as soon as one of the component densities violates the symmetry assumption. In this article, using ranks rather than signed ranks, we extend their approach to the asymmetric case and propose a one-step R-estimator for ICA mixing matrices. The finite-sample performances of those estimators are investigated and compared to those of existing methods under moderately large sample sizes. Particularly good performances are obtained from a version involving data-driven scores taking into account the skewness and kurtosis of residuals. Finally, we show, by an empirical exercise, that our methods also may provide excellent results in a context such as image analysis, where the basic assumptions of ICA are quite unlikely to hold. Supplementary materials for this article are available online.

A framework for automatic generation of security controller

SUMMARYThis paper concerns the study, the development and the synthesis of mechanisms for guaranteeing the security of complex systems, i.e. systems composed of several interacting components. A complex system under analysis is described as an open system, i.e. a system in which an unspecified component (a component whose behaviour is not fixed in advance) interacts with the known part of the system. Within this formal approach, we propose techniques that aim at synthesize controller programs able to guarantee that, for all possible behaviours of the unspecified component, the system should work properly, e.g. it should be able to satisfy a certain property. For performing this task, we first need to identify the set of necessary and sufficient conditions that the unspecified component has to satisfy in order to ensure that the whole system is secure. Hence, by exploiting the satisfiability procedures for temporal logic, we automatically synthesize an appropriate controller program that forces the unspecified component to meet these conditions. This will ensure the security of the whole system. In particular, we contribute within the area of the enforcement of security properties by proposing a flexible and automated framework that goes beyond the definition of how a system should behave to work properly. Indeed, while the majority of the related work focuses on the definition of monitoring mechanisms, we also address the synthesis problem. Moreover, we describe a tool for the synthesis of secure systems which is able to generate appropriate controller programs. This tool is also able to translate the synthesized controller programs into the ConSpec language. ConSpec programs can be actually deployed for enforcing security policies on mobile Java applications by using the run‐time framework developed in the ambit of the European Project S3MS. Copyright © 2010 John Wiley & Sons, Ltd.

Rank-based Inference for Multivariate Nonlinear and Long-memory Time Series Models

The portfolio of the Japanese Government Pension Investment Fund (GPIF) consists of a linear combination of five benchmarks of financial assets. Some of these exhibit long-memory and nonlinear behavior. Their analysis therefore requires multivariate nonlinear and long-memory time series models. Moreover, the assumption that the innovation densities underlying those models are known seems quite unrealistic. If those densities remain unspecified, the model becomes a semiparametric one, and rank-based inference methods naturally come into the picture. Rank-based inference methods under very general conditions are known to achieve the semiparametric efficiency bounds. Defining ranks in the context of multivariate time series models, however, is not obvious. We propose two distinct definitions. The first one relies on the assumption that the innovation density is some unspecified elliptical density. The second one relies on the assumption that the innovation process is described by some unspecified independent component analysis model. Applications to portfolio management problems are discussed.

Towards Information Flow Properties for Distributed Systems

In this paper we present a framework for the specification of information flow properties for distributed systems. We consider partially specified distributed systems in which there are several unspecified components located in different places. As a case study, in this paper we consider the notion of Non Deducibility on Composition, NDC for short, originally proposed for nondeterministic systems and based on trace semantics. We study how this information flow property can be extended in order to deal also with distributed partially specified systems. In particular, we adapt the NDC property to distributed systems by distinguishing between two different approaches. The first one we call centralized NDC, according to which there is just one unspecified global component that has complete control of the n distributed locations where interaction occurs between the system and the unspecified component. The second one is called distributed NDC, according to which there is one unspecified component for each distributed location, and the n unspecified components are completely independent, i.e., they cannot coordinate or cooperate each other. Surprisingly enough, we prove that centralized NDC is as discriminating as decentralized NDC. However, when we move to Bisimulation-based Non-Deducibility on Composition, BNDC for short, the situation is completely different. Indeed, we prove that centralized BNDC is strictly finer than decentralized BNDC, hence proving the quite expected fact that a system that can resist to coordinated attacks is also able to resist to simpler attacks performed by independent entities.

Efficient semiparametric estimator for heteroscedastic partially linear models

SUMMARY We study the heteroscedastic partially linear model with an unspecified partial baseline component and a nonparametric variance function. An interesting finding is that the performance of a naive weighted version of the existing estimator could deteriorate when the smooth baseline component is badly estimated. To avoid this, we propose a family of consistent estimators and investigate their asymptotic properties. We show that the optimal semiparametric efficiency bound can be reached by a semiparametric kernel estimator in this family. Building upon our theoretical findings and heuristic arguments about the equivalence between kernel and spline smoothing, we conjecture that a weighted partial spline estimator could also be semiparametric efficient. Properties of the proposed estimators are presented through theoretical illustration and numerical simulations.

An Efficient Adaptive Polarimetric Processor with an Embedded CFAR

To improve the detection performance of surveillance radars with polarization diversity, we developed an adaptive polarimetric processor and compared it with other polarimetric processors. We derived our adaptive polarimetric processor, called the polarization discontinuity detector (PDD), from the generalized likelihood ratio (GLR) test principle for the unspecified target component. We derived closed-form expressions of its probabilities of detection and false alarm, and compared its performance to that of the adaptive polarization canceller (APC) and Kelly's GLR processor. The PDD had a performance similar to Kelly's GLR in Gaussian clutter, and both the PDD and Kelly's GLR, which have embedded constant false alarm rates (CFARs), outperformed the APC, especially when the target polarization state was close to the clutter's polarization state. The important difference is that the PDD is much simpler than Kelly's GLR for hardware/software implementation, because the PDD does not require a costly two-parameter filter bank to cover the unknown target polarization state as Kelly's GLR does.

Isotopic Composition of Solar Wind Nitrogen: First In Situ Determination with the CELIAS/MTOF Spectrometer on board [ITAL]SOHO[/ITAL

Using the high-resolution Mass Time-of-Flight (MTOF) spectrometer of the Charge, Element, and Isotope Analysis System (CELIAS) experiment on board the Solar and Heliospheric Observatory (SOHO), we have determined the solar wind isotope abundance ratio 14N/15N = 200±55 (1 σ error), suggesting that the relative abundance of 15N in the terrestrial atmosphere is lower than in solar matter. This result is compatible with the hypothesis that terrestrial N (14N/15N = 272) and also N found in lunar surface material are a mixture of a heavy component that is identical to solar N and an unspecified light component. The large variations of 14N/15N in solar system matter is caused by special isotope enrichment processes, as in the case of Mars, as well as by varying contributions of isotopically different components.

SmNd isotopic and geochemical characterisation of the Paleoproterozoic Torngat orogen, Labrador, Canada

The Torngat orogen is a Paleoproterozoic, granulite-facies belt that welds the Archean components of the Nain and Rae provinces in eastern Labrador. SmNd isotopic and supporting bulk rock major, trace and rare earth element data help elucidate the sources of the main Paleoproterozoic lithologies that comprise the orogen. In the foreland, Paleoproterozoic Ramah Group metasediments intercalated with reworked Nain Province gneiss show variable trace element and ∈ Nd(1.9 Ga) from −2.9 to −12.0, ranging between Nain Province crust and Paleoproterozoic Mugford Group basalts compositions. The Ramah Group data suggest derivation of Ramah detritus from Archean Nain Province gneisses and from the Mugford Group. In the Lac Lomier complex (Rae Province hinterland), metasediments with variable trace element distribution patterns akin to Rae Province crust, and ∈ Nd(1.9 Ga) from −2.9 to −10.5 suggest derivation from Rae Province crust and from an unspecified juvenile component. In the core of the orogen, pelitic and psammitic protoliths of the Tasiuyak gneiss (∈ Nd(1.9 Ga) from −1.9 to −2.6) were derived from crustal sources unknown in both Nain and Rae provinces, and may have been deposited in a trench environment starved of adjacent cratonic debris. Dioritic to granitic eastern and western metaplutonic suites intruding the Tasiuyak gneiss and the Lac Lomier complex display contrasting geochemical and SmNd isotopic compositions. The eastern metaplutonic suite has a tendency toward lower SiO 2, total alkalis, less fractionated REE and higher MgO, CaO and TiO 2 relative to the western metaplutonic suite. The eastern suite yields ∈ Nd(1.9 Ga) from +3.8 to −6.7 and negative f Sm Nd suggesting igneous precursors from Rae crust and a a LREE-enriched juvenile component. The western suite yields ∈ Nd(1.9 Ga) from −1.5 to −8.5, suggesting an important contribution from Rae crustal sources in the petrogenesis of the igneous protoliths. The presence of Rae Province Nd isotopic compositions, and the absence of Nain Province signatures in these intrusions favors the eastern Rae Province as the active margin during Nain-Rae convergence.