Small Number Of Passes Research Articles

A retrospective histological comparison of EUS-guided fine-needle biopsy using a novel franseen needle and a conventional end-cut type needle.

Background and Objectives:Recently, a 22G Franseen needle for EUS-guided fine-needle biopsy (EUS-FNB) with three novel symmetric heels has been developed to adequately obtain a core tissue.Methods:All 38 consecutive patients with pancreatic masses who underwent EUS-FNB using a Franseen needle were investigated retrospectively to assess the efficacy and safety of EUS-FNB using the Franseen needle. Then, the EUS-FNB outcomes and histological assessments of the tissue obtained by EUS-FNB using the Franseen needle and EUS-FNA using the conventional end-cut type needle for each of the 30 pancreatic ductal adenocarcinoma cases were compared.Results:An accurate histological diagnosis of the Franseen needle was achieved with a mean of 2 passes in 97.4% of patients. Although the accurate histological diagnosis rate of pancreatic ductal adenocarcinoma was not significantly different (96.7% vs. 93.3%, P = 0.55), the mean number of passes in the Franseen needle was significantly less than that in the conventional needle (2.1 ± 0.4 vs. 3.2 ± 0.8, P < 0.001). The presence of desmoplastic fibrosis with neoplastic cellular elements and venous invasion were significantly higher (96.7% vs. 40.0%, P < 0.001 and 23.3% vs. 0%, P < 0.01, respectively) and the amount of obtained tissue was significantly larger with the Franseen needle (2.13 mm2 vs. 0.45 mm2, P < 0.001).Conclusions:EUS-FNB using the Franseen needle enables the acquisition of a larger amount of tissue sample and achieves an accurate histological diagnosis with a smaller number of passes than the conventional end-cut type needle.

A Geometric Approach to Archetypal Analysis and Nonnegative Matrix Factorization

ABSTRACTArchetypal analysis and nonnegative matrix factorization (NMF) are staples in a statistician's toolbox for dimension reduction and exploratory data analysis. We describe a geometric approach to both NMF and archetypal analysis by interpreting both problems as finding extreme points of the data cloud. We also develop and analyze an efficient approach to finding extreme points in high dimensions. For modern massive datasets that are too large to fit on a single machine and must be stored in a distributed setting, our approach makes only a small number of passes over the data. In fact, it is possible to obtain the NMF or perform archetypal analysis with just two passes over the data.

Influence of equal channel angular pressing temperature on texture, microstructure and mechanical properties of extruded AX41 magnesium

Abstract The objective of this study is the investigation of the effect of temperature of equal channel angular pressing (ECAP) on the microstructure, texture and mechanical properties of AX41 magnesium alloy. ECAP processing was performed at temperatures of 220 °C and 250 °C up to 8 passes via route Bc. It was found that during ECAP processing at 250 °C a smaller number of passes was enough to achieve a homogeneous microstructure than at 220 °C. However, the final grain size obtained after 8 passes at 250 °C was only 4 μm which is larger than the value of 2.7 μm achieved at 220 °C. Moreover, a significant influence of the temperature of ECAP processing on the dislocation density and the crystallographic texture was observed. The proof stress of the sample processed by 8 passes at 250 °C was lower than that obtained at 220 °C. It can be attributed to the lower dislocation density, the larger grain size and the texture, which facilitates the basal slip.

State-of-the-art on clustering data streams

Clustering is a key data mining task. This is the problem of partitioning a set of observations into clusters such that the intra-cluster observations are similar and the inter-cluster observations are dissimilar. The traditional set-up where a static dataset is available in its entirety for random access is not applicable as we do not have the entire dataset at the launch of the learning, the data continue to arrive at a rapid rate, we can not access the data randomly, and we can make only one or at most a small number of passes on the data in order to generate the clustering results. These types of data are referred to as data streams. The data stream clustering problem requires a process capable of partitioning observations continuously while taking into account restrictions of memory and time. In the literature of data stream clustering methods, a large number of algorithms use a two-phase scheme which consists of an online component that processes data stream points and produces summary statistics, and an offline component that uses the summary data to generate the clusters. An alternative class is capable of generating the final clusters without the need of an offline phase. This paper presents a comprehensive survey of the data stream clustering methods and an overview of the most well-known streaming platforms which implement clustering.

Improving Program Performance via Auto-Vectorization of Loops with Conditional Statements with GCC Compiler Setting

The GCC is an auto-vectorization compiler across iterations of loops to parallelism data. Turning GCC compiler optimizations flags for auto-vectorization is a way to improve the performance ability, which is a popular approach to speed up program performance. However, there are many options in GCC compiler and selecting the best combination of these options to improve program performance through vectorization is non-trivial ( as the search space is very large ).In this work we focus on the selection of compiler transformations to auto-vectorize loops with conditional statements. The selection of compiler transformations is based on the correlation between program features, speed-up, and the analysis of the code generated and a small number of passes of iterative compilation. Our preliminary experimental results show that proposed technique attains performance improvements the best ~ 6x using loops in the TSVC benchmark suite on the state-of-the-art Intel Core i3 processor.

Estimating PageRank on graph streams

This article focuses on computations on large graphs (e.g., the web-graph) where the edges of the graph are presented as a stream. The objective in the streaming model is to use small amount of memory (preferably sub-linear in the number of nodes n ) and a smaller number of passes. In the streaming model, we show how to perform several graph computations including estimating the probability distribution after a random walk of length l , the mixing time M , and other related quantities such as the conductance of the graph. By applying our algorithm for computing probability distribution on the web-graph, we can estimate the PageRank p of any node up to an additive error of √ε p +ε in Õ (√ M /α) passes and Õ (min( n α+1/ε√ M /α+(1/ε) M α, α n √ M α + (1/ε)√ M /α)) space, for any α ∈ (0,1]. Specifically, for ε = M / n , α = M −1/2 , we can compute the approximate PageRank values in Õ( nM −1/4 ) space and Õ( M 3/4 ) passes. In comparison, a standard implementation of the PageRank algorithm will take O(n) space and O(M) passes. We also give an approach to approximate the PageRank values in just Õ(1) passes although this requires Õ( nM ) space.

Contour Stencils: Total Variation along Curves for Adaptive Image Interpolation

Image interpolation is the problem of increasing the resolution of a given image. An important aspect of interpolation is accurate estimation of edge orientations. This work introduces contour stencils, a new method for estimating the image contours based on total variation along curves. Contour stencils are able to distinguish lines of different orientations, curves, corners, and other geometric features with a computationally efficient formula. Contour stencils are applied in designing an edge directed color interpolation method. The method incorporates an efficient approximation of deconvolution. Although most interpolation methods that involve deconvolution require either solving a large linear system or running many iterations, this method has linear complexity in the number of pixels and can be computed in one or a small number of passes through the image. Comparisons show that the proposed interpolation is competitive with existing methods.

Optimal and Practical Algorithms for Sorting on the PDM

The parallel disks model (PDM) has been proposed to alleviate the I/O bottleneck that arises in the processing of massive data sets. Sorting has been extensively studied on the PDM model due to the fundamental nature of the problem - several asymptotically optimal algorithms are known for sorting. Although randomization has been frequently exploited, most of the prior algorithms suffer from complications in memory layouts, implementation, restrictions in range of parameters, and laborious analysis. In this paper, we present a randomized mergesort algorithm based on a simple idea that sorts using an asymptotically optimal number of I/O operations with high probability and has all of the desirable features for practical implementation. In the second part of the paper, we also present several novel algorithms for sorting on the PDM that take only a small number of passes through the data. Recently, considerable interest has been shown by researchers in developing algorithms for problem sizes of practical interest and we are able to obtain several improvements and simplification, in particular for random input.

Mechanochemical Reactions in Black-Filled SBR Vulcanizates under Large Deformation

Abstract Mechanochemical degradation of black-filled SBR's at large deformation was studied in relation to abrasion. Deformation of rubbers caused bond scission and reduced the crosslink density; however, subsequent free radical reactions reconstructed the network structure in a short time to some extents depending on the strain. The extent of crosslink recovery was larger with larger strains. As a consequence, the loss in crosslink density showed a peak when plotted against the strain. When rubber was deformed by repeatedly passing through a narrow gap of a two-roll mill, the crosslink density was raised appreciably above the original level after a small number of passes. Surprisingly, the rubber could become plastic-like while the crosslink density was maintained high. All of these results matched well with the characteristic phenomena observed in abrasion of rubbers, e.g., the varying appearance of wear with severity, the worn surface and debris prone to be oxidized, and the bimodal size distribution of debris. It was strongly suggested that mechanochemical degradation participated in abrasion in a wide range of severity.

Multi-Pass Geometric Algorithms

We propose the study of exact geometric algorithms that require limited storage and make only a small number of passes over the input. Fundamental problems such as low-dimensional linear programming and convex hulls are considered.

Fast and exact out-of-core and distributed k-means clustering

Clustering has been one of the most widely studied topics in data mining and k-means clustering has been one of the popular clustering algorithms. K-means requires several passes on the entire dataset, which can make it very expensive for large disk-resident datasets. In view of this, a lot of work has been done on various approximate versions of k-means, which require only one or a small number of passes on the entire dataset.In this paper, we present a new algorithm, called fast and exact k-means clustering (FEKM), which typically requires only one or a small number of passes on the entire dataset and provably produces the same cluster centres as reported by the original k-means algorithm. The algorithm uses sampling to create initial cluster centres and then takes one or more passes over the entire dataset to adjust these cluster centres. We provide theoretical analysis to show that the cluster centres thus reported are the same as the ones computed by the original k-means algorithm. Experimental results from a number of real and synthetic datasets show speedup between a factor of 2 and 4.5, as compared with k-means.This paper also describes and evaluates a distributed version of FEKM, which we refer to as DFEKM. This algorithm is suitable for analysing data that is distributed across loosely coupled machines. Unlike the previous work in this area, DFEKM provably produces the same results as the original k-means algorithm. Our experimental results show that DFEKM is clearly better than two other possible options for exact clustering on distributed data, which are down loading all data and running sequential k-means or running parallel k-means on a loosely coupled configuration. Moreover, even in a tightly coupled environment, DFEKM can outperform parallel k-means if there is a significant load imbalance.

Clustering data streams: theory and practice

The data stream model has recently attracted attention for its applicability to numerous types of data, including telephone records, Web documents, and clickstreams. For analysis of such data, the ability to process the data in a single pass, or a small number of passes, while using little memory, is crucial. We describe such a streaming algorithm that effectively clusters large data streams. We also provide empirical evidence of the algorithm's performance on synthetic and real data streams.

Microstructural Change during the Hot Working of As-Cast Austenite

The direct hot rolling of the as-cast austenite of thin slab castings requires the microstructural changes within the austenite phase field that are necessary for a satisfactory product to be accommodated within a smaller degree of total reduction, within a smaller number of passes, and within a shorter time scale. Particularly in the case of microalloyed steel, the constitution of the as-cast austenite prior to rolling differs from that of austenite of thick slabs reheated for conventional hot rolling. Consequently, the models developed for conventional rolling employing reheated austenite cannot be relied upon for predicting microstructural change during the rolling of as-cast austenite. The as-cast austenite of microalloyed steels has larger grains, is segregated, and carbonitride precipitates may be present that are not in equilibrium with their solid solution. These factors are discussed in the light of recent research. It is suggested that recrystallisation kinetics should be linearly, rather than quadratically, related to austenite grain size, and that above a limiting carbon content the addition of Nb and Ti results in excess, eutectically precipitated, Nb-rich carbonitride due to segregation during freezing. The former leads to more rapid recrystallisation than would be predicted by the conventional models, and helps to ensure that plain C-Mn steels can be satisfactorily processed. The presence of eutectic carbonitrides means that the supersaturation of the austenite with respect to microalloy constituents is unknown, and recrystallisation-stop temperatures cannot be modelled satisfactorily.

The relationship between microstructure and wear of mica-containing glass-ceramics

A series of mica-containing glass-ceramics with three different mica platelet sizes were tested for wear against a harder alumina counterface in a pin-on-disk tribometer under distilled water lubrication. Under all test conditions (i.e. different loads and number of passes), the wear rate increased with the increase in mica platelet diameter. Examination of the wear scars on the glass-ceramic samples using a scanning electron microscope indicated that the wear process was dominated by a microfracture mechanism either along the mica cleavage planes or along the weak mica-glass interfaces. Three wear modes were observed. (1) At low loads and small number of passes, wear occurred by formation of isolated fracture sites on the wear track. No measurable wear took place during this ‘localized fracture’ wear mode. (2) The number of fracture sites increased and covered the entire contact width as the load or number of passes increased. This ‘contact fracture’ mode resulted in wear factors on the order of 10 −4 mm 3 Nm −1. (3) At higher loads or after a large number of passes, accumulation of subsurface microfracture damage led to ‘spallation’ wear mode which resulted in wear factors on the order of 10 −2 mm 3 Nm −1. The mica platelet diameter was found to be an important factor in controlling the wear modes and wear transfusion. The transitions from ‘localized fracture’ to ‘contact fracture’ and to ‘spallation’ occurred at lower loads and smaller number of passes as the mica plate diameter was increased.

Transistor reordering for power minimization under delay constraint

In this article we address the problem of optimization of VLSI circuits to minimize power consumption while meeting performance goals. We present a method of estimating power consumption of a basic or complex CMOS gate which takes the internal capacitances of the gate into account. This method is used to select an ordering of series-connected transistors found in CMOS gates to achieve lower power consumption. The method is very efficient when used by library-based design styles. We describe a multipass algorithm that makes use of transistor reordering to optimize performance and power consumption of circuits, has a linear time complexity per pass, and converges to a solution in a small number of passes. Transformations in addition to transistor reordering can be used by the algorithm. The algorithm has been benchmarked on several large examples and the results are presented.

Fine Needle Aspiration in the Chest under CT Control

Over a 42 month period 133 patients underwent 148 CT guided biopsies of 104 pulmonary lesions (78%), 21 mediastinal/hilar masses (16%) and 8 pleural lesions (6%). There were 48 cases (32%) complicated by a pneumothorax, of which 13 (9%) required a chest drain. Two cases each of minor haemopneumothorax (1.4%) and haematoma (1.4%) were found, and haemoptysis occurred in a single patient (0.7%). This low complication rate reflects the use of the 22 gauge Chiba needle, the small number of passes undertaken at each sitting and the wide range of lesion size. In four cases no diagnosis was established either at the time of biopsy or subsequently. There were 100 cases proven to be malignant, of which 81 were diagnosed at the first biopsy. Three further cases were regarded as suspicious of malignancy. Of the 29 patients with benign disease, a specific diagnosis was made in 10 (34%) and nonspecific inflammation was seen in 17 (59%) further patients. Fine needle aspiration under CT control is a useful and accurate diagnostic technique. It has widened the scope of lesions which can be biopsied, enabling small, deep or necrotic parenchymal lesions to be targeted accurately. A precise placement of the needle tip into pleural or mediastinal lesions is a further advantage. However, if an inadequate sample is obtained, the biopsy may need to be repeated.

Efficient algorithm for graph-partitioning problem using a problem transformation method

This paper shows that the uniform k- way partitioning problem can be transformed into the max-cut problem using a graph modification technique. An iterative algorith, based on Kernighan-Lin's (KL) method, for partitioning graphs is presented that exploits the problem equivalence property. The algorithm deals with nodes of various sizes without any performance degradation. The computing time per pass of the algorithm is O(itkN 2), where N is the number of nodes in the given graph. In practice, only a small number of passes are typically needed, leading to a fast approximation algorithm for k- way partitioning. Experimental results show that the proposed algorithm outperforms the KL algorithm in the quality of solutions. The performance gap between the proposed and KL algorithms becomes much bigger as the amount of size differences between nodes increases.

多層かど継手部の溶接割れに関する研究

Lamellar tearing of opening type and root cracking occasionally occur in multipass welded corner joints.In this paper, the influence of welding methods such as submerged arc welding (SAW) and covered arc welding (SMAW) is investigated on the occurrence of these weld cracks. The main results obtained in this study are as follows.(1) When SAW is applied, the transverse welding residual stress (σx) is less on the edge surface of the vertical plate and the lamellar tearing is less probable to occur in comparison with SMAW.(2) By SAW, σx, induced at the root is less and root cracking is less probable to occur against SMAW.Accordingly, in order to prevent occurrence of the weld cracks in multipass welded corner joints, it is effective to use SAW whose deposited metal weight per unit welding pass is large and which enables to fill up a given groove with smaller number of passes.