Chatter Diagnosis in Milling Using Supervised Learning and Topological Features Vector

Chatter detection has become a prominent subject of interest due to its effect on cutting tool life, surface finish and spindle of machine tool. Most of the existing methods in chatter detection literature are based on signal processing and signal decomposition. In this study, we use topological features of data simulating cutting tool vibrations, combined with four supervised machine learning algorithms to diagnose chatter in the milling process. Persistence diagrams, a method of representing topological features, are not easily used in the context of machine learning, so they must be transformed into a form that is more amenable. Specifically, we will focus on two different methods for featurizing persistence diagrams, Carlsson coordinates and template functions. In this paper, we provide classification results for simulated data from various cutting configurations, including upmilling and downmilling, in addition to the same data with some added noise. Our results show that Carlsson Coordinates and Template Functions yield accuracies as high as 96% and 95%, respectively. We also provide evidence that these topological methods are noise robust descriptors for chatter detection

Differential expression of HSPA1 and HSPA2 proteins in human tissues; tissue microarray-based immunohistochemical study

In the present study we determined the expression pattern of HSPA1 and HSPA2 proteins in various normal human tissues by tissue-microarray based immunohistochemical analysis. Both proteins belong to the HSPA (HSP70) family of heat shock proteins. The HSPA2 is encoded by the gene originally defined as testis-specific, while HSPA1 is encoded by the stress-inducible genes (HSPA1A and HSPA1B). Our study revealed that both proteins are expressed only in some tissues from the 24 ones examined. HSPA2 was detected in adrenal gland, bronchus, cerebellum, cerebrum, colon, esophagus, kidney, skin, small intestine, stomach and testis, but not in adipose tissue, bladder, breast, cardiac muscle, diaphragm, liver, lung, lymph node, pancreas, prostate, skeletal muscle, spleen, thyroid. Expression of HSPA1 was detected in adrenal gland, bladder, breast, bronchus, cardiac muscle, esophagus, kidney, prostate, skin, but not in other tissues examined. Moreover, HSPA2 and HSPA1 proteins were found to be expressed in a cell-type-specific manner. The most pronounced cell-type expression pattern was found for HSPA2 protein. In the case of stratified squamous epithelia of the skin and esophagus, as well as in ciliated pseudostratified columnar epithelium lining respiratory tract, the HSPA2 positive cells were located in the basal layer. In the colon, small intestine and bronchus epithelia HSPA2 was detected in goblet cells. In adrenal gland cortex HSPA2 expression was limited to cells of zona reticularis. The presented results clearly show that certain human tissues constitutively express varying levels of HSPA1 and HSPA2 proteins in a highly differentiated way. Thus, our study can help designing experimental models suitable for cell- and tissue-type-specific functional differences between HSPA2 and HSPA1 proteins in human tissues

Fascia lata graft for urethral fistula repair - Reply

WOS: 00022266310005

Stone formation on surgical staple in the bladder: A long-term complication of laparoscopic colposuspension

We present a case of a bladder stone that developed around a surgical staple after laparoscopic colposuspension. The patient had undergone laparoscopic colposuspension for stress urinary incontinence at another institution 6 years ago. The hernia mesh and a tacker had been used as a surgical stapler. The stone and staple were retrieved endoscopically. To our knowledge, this is the first case of such a complication after laparoscopic colposuspension with a stapling device. © 2007 Lippincott Williams & Wilkins, Inc

Transfer Learning for Autonomous Chatter Detection in Machining

Large-amplitude chatter vibrations are one of the most important phenomena in machining processes. It is often detrimental in cutting operations causing a poor surface finish and decreased tool life. Therefore, chatter detection using machine learning has been an active research area over the last decade. Three challenges can be identified in applying machine learning for chatter detection at large in industry: an insufficient understanding of the universality of chatter features across different processes, the need for automating feature extraction, and the existence of limited data for each specific workpiece-machine tool combination. These three challenges can be grouped under the umbrella of transfer learning. This paper studies automating chatter detection by evaluating transfer learning of prominent as well as novel chatter detection methods. We investigate chatter classification accuracy using a variety of features extracted from turning and milling experiments with different cutting configurations. The studied methods include Fast Fourier Transform (FFT), Power Spectral Density (PSD), the Auto-correlation Function (ACF), Wavelet Packet Transform (WPT), and Ensemble Empirical Mode Decomposition (EEMD). We also examine more recent approaches based on Topological Data Analysis (TDA) and similarity measures of time series based on Discrete Time Warping (DTW). We evaluate the transfer learning potential of each approach by training and testing both within and across the turning and milling data sets. Our results show that carefully chosen time-frequency features can lead to high classification accuracies albeit at the cost of requiring manual pre-processing and the tagging of an expert user. On the other hand, we found that the TDA and DTW approaches can provide accuracies and F1 scores on par with the time-frequency methods without the need for manual preprocessing

Nocturnal enuresis and allergy

Objective. To investigate whether an interaction exists between nocturnal enuresis and allergy. Material and methods. Thirty-seven (20 boys, 17 girls) children with monosymptomatic nocturnal enuresis were recruited. We studied an allergy panel that included total IgE, 10 examples of inhalant-specific IgE, 10 examples of food-specific IgE, eosinophilic cationic protein (ECP) and Phadiotop. The same panel was studied in a control group of 18 children without monosymptomatic nocturnal enuresis. Results. We did not determine statistically significant differences between the enuretic group and the control group in terms of levels of total IgE, the 10 examples of inhalant-specific IgE and Phadiotop. However, two (soybean and hazelnut) of the 10 food-specific IgE and ECP levels did differ significantly between the two groups. Conclusions. This first specific IgE study showed that there may be a relationship between nocturnal enuresis and soybean and hazelnut food allergens. Our findings may explain some cases of nocturnal enuresis. However, further studies are necessary to explain the underlying mechanisms and management of this disorder. © 2005 Taylor & Francis

Partial nephrectomy using a monopolar radiofrequency device: An animal model

Objectives: To compare the use of radiofrequency (RF) and electrocautery in partial nephrectomy without renal artery clamping for bleeding and tissue destruction. Methods: Sixteen adult rabbits were randomized into two groups. Partial nephrectomy using a monopolar RF device without renal artery clamping was performed in 8 rabbits (RF group) and partial nephrectomy using electrocautery was performed in the rest (cautery group). Four rabbits in each group (rabbits 1, 3, 5, and 7) were kept for follow-up, and the operated kidneys of the rest were removed for histopathologic evaluation. The tissue samples were placed in 10% formalin solution and sent to the pathology laboratory. The groups were compared in terms of bleeding and tissue destruction. Results: The mean blood loss was 3.6 ± 1.2 mL in the RF group and 8.3 ± 2.7 mL in the control group (P = 0.003). A rabbit in the control group died on postoperative day 3 because of bleeding. Others were followed up for 3 months postoperatively. The amount of thermal destruction was comparable between the two groups. Varying degrees of thermal destruction were observed at the cutting margins in both groups. No difference was found between the two groups in terms of the deepness of thermal injury (1 to 2 mm). Conclusions: The findings of our experimental study showed that the use of the RF electrode in partial nephrectomy without renal artery clamping resulted in less intraoperative bleeding without differences in terms of tissue destruction. © 2006 Elsevier Inc. All rights reserved