Challenges and Opportunities of System-Level Prognostics.

Prognostics and health management (PHM) has become an essential function for safe system operation and scheduling economic maintenance. To date, there has been much research and publications on component-level prognostics. In practice, however, most industrial systems consist of multiple components that are interlinked. This paper aims to provide a review of approaches for system-level prognostics. To achieve this goal, the approaches are grouped into four categories: health index-based, component RUL-based, influenced component-based, and multiple failure mode-based prognostics. Issues of each approach are presented in terms of the target systems and employed algorithms. Two examples of PHM datasets are used to demonstrate how the system-level prognostics should be conducted. Challenges for practical system-level prognostics are also addressed.

Review of Regulatory Emphasis on Transportation Safety in the United States, 2002-2009: Public versus Private Modes.

The U.S. Department of Transportation is responsible for implementing new safety improvements and regulations with the goal of ensuring limited funds are distributed to where they can have the greatest impact on safety. In this work, we conduct a study of new regulations and other reactions (such as recalls) to fatal accidents in several different modes of transportation implemented from 2002 to 2009. We find that in the safest modes of commercial aviation and bus transport, the amount of spending on new regulations is high in relation to the number of fatalities compared to the regulatory attention received by less safe modes of general aviation and private automobiles. Additionally, we study two major fatal accident investigations from commercial aviation and two major automotive recalls associated with fatal accidents. We find differences in the cost per expected fatality prevented for these reactions, with the airline accident investigations being more cost effective. Overall, we observe trends in both the automotive and aviation sectors that suggest that public transportation receives more regulatory attention than private transport. We also observe that the types of safety remedies utilized, regulation versus investigation, have varying levels of effectiveness in different transport modes. We suggest that these differences are indicative of increased public demand for safety in modes where a third party may be held responsible, even for those not participating in the transportation. These findings have important implications for the transportation industry, policymakers, and for estimating the public demand for safety in new transport modes.

Efficacy, safety and albuminuria-reducing effect of gemigliptin in Korean type 2 diabetes patients with moderate to severe renal impairment: A 12-week, double-blind randomized study (the GUARD Study).

AIMS: This multicentre, randomized, double-blind study investigated the efficacy and safety of gemigliptin in Korean type 2 diabetes mellitus (T2DM) patients with moderate to severe renal impairment (RI). METHODS: The study comprised a 12-week main part and a 40-week extension. We report here the results from the main part. In total, 132 patients were randomized to receive gemigliptin (n = 66) or placebo (n = 66). Changes in glycated haemoglobin (HbA1c; primary endpoint), other glycaemic control parameters (fasting plasma glucose, glycated albumin and fructosamine), lipid profiles, renal function parameters and safety profiles were evaluated. RESULTS: Baseline characteristics were comparable between the groups (mean HbA1c, 8.4% [68 mmol/mol]; age, 62.0 years; duration of type 2 diabetes, 16.3 years; estimated glomerular filtration rate, 33.3 mL/min/1.73 m2 ). At Week 12, the adjusted mean change ± standard error in HbA1c with gemigliptin was -0.82% ± 0.14% (-8.9 ± 1.5 mmol/mol), whereas it was 0.38% ± 0.14% (4.2 ± 1.5 mmol/mol) with placebo (significant between-group difference, P < .001). Other glycaemic control parameters showed beneficial changes as well. Body weight change (gemigliptin, -0.3 kg; placebo, -0.2 kg) was not significant. In the gemigliptin group, the mean decrease in urinary albumin creatinine ratio (UACR) was significant, both in patients with microalbuminuria (-41.9 mg/g creatinine, P = .03) and macroalbuminuria (-528.9 mg/g creatinine, P < .001). Drug-related adverse events were similar with gemigliptin and placebo (15% and 12%, respectively). CONCLUSIONS: A 12-week treatment with gemigliptin improved glycaemic control and provided UACR reduction in T2DM patients with moderate to severe RI. Gemigliptin was well tolerated, with no additional risk of hypoglycaemia and change in body weight.

Measurement of serum 3-epi-25-hydroxyvitamin D3, 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in infant, paediatric and adolescent populations of Korea using ultra-performance liquid chromatography-tandem mass spectrometry.

Background We evaluated the performance of ultra-performance liquid chromatography-tandem mass spectrometry to measure serum 3-epi-25-hydroxyvitamin D3, 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 concentrations in 519 infant, paediatric and adolescent serum samples in Korea. Methods We used a Kinetex XB-C18 column and isocratic methanol/water (77.5/22.5, v/v) with 0.025% (v/v) high-performance liquid chromatography solvent additive flowing at 0.25 mL/min, yielding an 11 min/sample run time. A TQD triple quadrupole mass spectrometer in electrospray ionization positive ion mode with multiple reaction monitoring transition via an MSMS vitamin D kit was used to evaluate precision, carryover, ion suppression and linearity. Samples were prepared using the 4-phenyl-1,2,4-triazoline-3,5-dione derivatization method. Results Intra- and inter-run precisions were 1.23-13.28% and 1.02-10.08%, respectively. Group carryovers were -0.27% and 0.10%, respectively. There was no ion suppression. The calibration curve showed good linearity from calibrator Level 1 (11.75 nmol/L) to 6 (375 nmol/L) with R2 > 0.9999. The 3-epi-25-hydroxyvitamin D3 and 25-hydroxyvitamin D3 peaks were clearly separated in the extracted ion chromatogram. Infant serum samples 3-epi-25-hydroxyvitamin D3 concentrations were significantly higher than paediatric and adolescent concentrations. Conclusions The ultra-performance liquid chromatography-tandem mass spectrometry assay performed acceptably, clearly separating 3-epi-25-hydroxyvitamin D3 from 25-hydroxyvitamin D3. High 3-epi-25-hydroxyvitamin D3 concentrations were observed in infant but not in paediatric and adolescent serum samples.

Electrostatic precursors to granular slip events.

It has been known for over a century that electrical signals are produced by material failure, for example during crack formation of crystals and glasses, or stick-slip motion of liquid mercury on glass. We describe here new experiments revealing that slip events in cohesive powders also produce electrical signals, and remarkably these signals can appear significantly in advance of slip events. We have confirmed this effect in two different experimental systems and using two common powdered materials, and in a third experiment we have demonstrated that similar voltage signals are produced by crack-like defects in several powdered materials.

Reformulation in the phase plane enhances smoothness rater accuracy in stroke.

To improve the characterization of motor impairment, we compared the sensitivities of a phase plane metric with temporal domain measures derived from integrated squared jerk (ISJ). Five subjects with stroke and a cohort of 21 neurologically intact volunteers performed self-paced, isolated elbow flexions. Analysis of angular trajectories from the stroke group revealed that temporal domain metrics failed to detect a performance deficit at the p < .05 level, while the phase plane metric did resolve a deficit (p < .01). When applied to a subset of movements with arrest periods, the phase measure also uniquely identified impairment (Wilcoxon rank-sum test, p < .001). Finally, when tested on a data-driven model, the phase measure, but not temporal metrics, increased monotonically with the severity of trajectory distortions. We conclude that motion smoothness can be accurately measured in the phase plane.

Relating biceps EMG to elbow kinematics during self-paced arm flexions.

Repetitive reaching movements to a fixed target can be generally characterized by bell-shaped velocity profiles and sigmoidal trajectories with variable morphologies across multiple repetitions. A neuromuscular correspondence of these kinematic variations has thus far eluded electromyographic (EMG) analysis. We recorded EMG and elbow kinematics from fourteen healthy individuals performing repetitive, self-paced, isolated elbow flexions, with their arms supported against gravity. The global kinematic pattern of each flexion was classified as either sigmoidal (S) or non-sigmoidal (NS), based on goodness of fit with analytical curves. Ten of the fourteen subjects generated an approximately equal number of S and NS types (383 movement cycles). Trajectories of the other four subjects were not classifiable or did not vary sufficiently and were excluded from subsequent analysis. A post hoc predictor of trajectory type was derived by testing linear support vector machines trained with a strategically selected 3-feature sub-space of the early phase of enveloped biceps EMG during a leave-one-out cross-validation paradigm. Results showed that EMG features predicted kinematic morphology with sensitivity and specificity both exceeding 80%. The high predictive accuracy suggests neuromotor signals coding for subtle variations in elbow kinematics during self-paced, unloaded motions, can be deciphered from the biceps EMG.

(-)-Epigallocatechin-3-gallate inhibits monocyte chemotactic protein-1 expression in endothelial cells via blocking NF-kappaB signaling.

Monocyte chemotactic protein-1 (MCP-1) is a potent chemoattractant for monocytes and plays a key role in various inflammatory responses, including atherosclerosis. In this study, we examined the effect of (-)-epigallocatechin-3-gallate (EGCG), a major green tea catechin, on the expression of MCP-1 in human endothelial ECV304 cells. EGCG markedly inhibited the phorbol 12-myristate 13-acetate (PMA)-induced MCP-1 mRNA and protein levels in a dose-dependent manner. EGCG was also found to reduce the MCP-1 transcriptional activity. The upregulation of MCP-1 by PMA was significantly inhibited by blockade of P38 mitogen-activated protein kinase (MAPK) and NF-kappaB, but not by blockade of extracellular-signal-regulated kinase and c-Jun N-terminal kinase pathway. Furthermore, The PMA-induced p38 MAPK and NF-kappaB activation were obviously attenuated after pretreating ECV304 cells with EGCG. The conditioned media from the endothelial ECV304 cells treated with PMA could remarkably stimulate the migration of THP-1 monocytes and this effect was partially abrogated by MCP-1 neutralizing antibodies. Moreover, the media from the EGCG-pretreated ECV304 cells lost the stimulatory activity for THP-1 migration. These results suggest that EGCG may exert an anti-inflammatory effect in endothelial cells by controlling MCP-1 expression, at least in part, mediated through the suppression of p38 MAPK and NF-kappaB activation.

Three-dimensional localization of cochlear implant electrodes using epipolar stereophotogrammetry.

Three-dimensional (3-D) localization of individual cochlear implant electrodes within the inner ear is of importance for modeling the electrical field of the cochlea, designing the electrode array, and programming the associated speech processor. A 3-D reconstruction method of cochlear implant electrodes is proposed to localize individual electrodes from two X-ray views in combination with the spiral computed tomography technique. By adapting epipolar geometry to the configuration of an X-ray imaging system, we estimate individual electrode locations in the least square sense without using a patient attachment required by an existing stereophotogrammetry technique. Furthermore, our method does not require any knowledge of the intrinsic and extrinsic parameters of the imaging system. The performance of our method is studied in numerical simulation and with patient data and is found to be sufficiently accurate for clinical use. The maximum root mean-square errors measured are 0.0445 and 0.214 mm for numerical simulation and patient data, respectively.

Design of multimedia telemedicine system for inter-hospital consultation.

The telemedicine systems for the decision of patient transfer, and the direction of patient treatment through remote consultation are necessarily required for better patient care in emergency situation. In this paper, the prototype emergency telemedicine system has been designed and implemented. The unified integration of multimedia components, including full-quality video, vital sign signals, radiological images and video conferencing in a single computer, provides an efficient means to investigate the accurate status of emergency patient at the remote location. The software implementation of needed functionality without any externally attached hardware CODEC units enables the compact design with low cost, and ease of operation at the emergency room. Experimental tests at the local networks analyze the technical aspects of implemented systems, and optimize the parameters subjectively to run telemedicine systems with affordable error. Inter-hospital experiments demonstrate the possibility to be effectively used at emergency situation.

Alignment of CT images of skull dysmorphology using anatomy-based perpendicular axes.

Rigid body registration of 3D CT scans, based on manual identification of homologous landmarks, is useful for the visual analysis of skull dysmorphology. In this paper, a robust and simple alignment method was proposed to allow for the comparison of skull morphologies, within and between individuals with craniofacial anomalies, based on 3D CT scans, and the minimum number of anatomical landmarks, under rigidity and uniqueness constraints. Three perpendicular axes, extracted from anatomical landmarks, define the absolute coordinate system, through a rigid body transformation, to align multiple CT images for different patients and acquisition times. The accuracy of the alignment method depends on the accuracy of the localized landmarks and target points. The numerical simulation generalizes the accuracy requirements of the alignment method. Experiments using a human dried skull specimen, and ten sets of skull CT images (the pre- and post-operative CT scans of four plagiocephaly, and one fibrous dysplasia patients), demonstrated the feasibility of the technique in clinical practice.

Polygon reduction of 3D objects using Stokes' theorem.

Surface over volume rendering can be useful for many applications. However, the tremendously large number of polygons composing the surface primitives should be reduced to a manageable size so as to utilize the capability of low cost hardware and software rendering engines, a standard Internet protocol and VRML format. In this paper, we propose a novel algorithm that deletes several vertices simultaneously by forming a closed arbitrary shaped boundary. The Stokes' theorem, used in electro-magnetic field analysis, was newly adapted to extract the arbitrary shaped boundary. The simultaneous deletion procedure provides a computational gain and increases the reduction ratio without sacrificing the topological distortion of the original mesh. Numerically synthesized polygonal objects and real CT data were tested to evaluate the performance of the new algorithm and to demonstrate the possibility of a medical rendering application. The new algorithm outperforms the conventional decimation algorithm in both computational and reduction efficiency.

Improvement of multi-channel isolated bio-potential amplifiers using multiplexing.

We propose a simple isolated link circuit for a multi-channel bio-potential amplifier, by adapting the multiplexing/demultiplexing technique that is generally used in digital circuit design. The reduced number of isolation amplifiers, due to the multiplexing technique, results in an increase in the amount of isolation, as well as a reduction in manufacturing cost. The simple incorporation of a dead-zone in multiplexed timing, and a pull-down resistor in the multiplexed signal line, enables a multiple isolated bio-signal transmission over the shared isolation amplifier, with an affordable inter-channel cross talk.