261 research outputs found
PIG883097 Supplemetal Material - Supplemental material for Effect of propeller-induced flow on the performance of biplane micro air vehicle dynamics
No full textSupplemental material, PIG883097 Supplemetal Material for Effect of propeller-induced flow on the performance of biplane micro air vehicle dynamics by Shuvrangshu Jana, Harikumar Kandath, Mayur Shewale and M Seetharama Bhat in Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering</p
A Crown Quantization-Based Approach to Tree-Species Classification Using High-Density Airborne Laser Scanning Data
No full textCrown features derived from high-density airborne laser scanning (ALS) data have proven to be effective for forest species classification at the individual tree level. Most of the general state-of-the-art (SoA) techniques rely on coarse-level crown features extracted from ALS data and under-utilize both the spatial and the spectral information available in the point clouds, Moreover, they are designed on the expected properties of the specific analyzed forest. We present a novel species classification approach, based on quantization of the entire 3-D tree crown into smaller elementary crown volumes (ECVs) that effectively captures the spatial distribution of filled (i.e., stem, branch, and foliage) and empty volumes of crowns. In the first step, a data-driven process dynamically tests and compares three quantization strategies to tailor the definition of the ECV to the forest type (e.g., conifer and deciduous forest). In the second step, for each ECV, a histogram vector is made up of features representing the light detection and ranging (LiDAR) point distribution and intensity to model the internal and the external local crown characteristics. Then, tree histogram feature vectors are obtained by stacking all the ECV histogram feature vectors. Finally, classification is performed by a support vector machine (SVM) classifier using the histogram intersection kernel. All experiments were performed on three high-density (50–200 points/m 2 ) ALS data sets of deciduous, conifer, and mixed (i.e., both deciduous and conifer) trees. The higher classification accuracy of the proposed method over the SoA one proves its ability to better capture the crown characteristics of individual trees, including species-specific traits
Statistical process control approach to reduce the bullwhip effect
No full textThesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2007.Includes bibliographical references (leaves 66-68).The bullwhip effect is a pervasive problem in multi echelon supply chains that results in inefficient production operations and higher inventory levels. The causes of the bullwhip effect are well understood in industry and academia. Quantitative and qualitative solutions to attenuate this effect have been proposed in various research studies. In this research a quantitative solution in the form of a Statistical Process Control (SPC) based inventory management system is proposed that reduces the bullwhip effect while reducing inventory without compromising service level requirements for a variety of products. The strength of this methodology is in its effectiveness in reducing bullwhip for fast moving products in the mature phase of their lifecycles where improving production efficiency and lowering inventory investment are critical. However, fill rate issues are observed for slow moving products and therefore, the methodology is not recommended for such products. Finally, the application of this methodology to reduce the bullwhip effect is illustrated for a product family of a medical devices company. The results for the different classes of products in this family are discussed.by Harikumar Iyer [and] Saurabh Prasad.M.Eng.in Logistic
Optimization of cat's whiskers tea (orthosiphon stamineus) using supercritical carbon dioxide and selective chemotherapeutic potential against prostate cancer cells
No full textCat's whiskers (Orthosiphon stamineus) leaves extracts were prepared using supercritical CO₂ (SC-CO₂) with full factorial design to determine the optimum extraction parameters. Nine extracts were obtained by varying pressure, temperature, and time. The extracts were analysed using FTIR, UV-Vis, and GC-MS. Cytotoxicity of the extracts was evaluated on human (colorectal, breast, and prostate) cancer and normal fibroblast cells. Moderate pressure (31.1 MPa) and temperature (60°C) were recorded as optimum extraction conditions with high yield (1.74%) of the extract (B2) at 60 min extraction time. The optimized extract (B2) displayed selective cytotoxicity against prostate cancer (PC3) cells (IC₅₀ 28 µg/mL) and significant antioxidant activity (IC₅₀ 42.8 µg/mL). Elevated levels of caspases 3/7 and 9 in B2-treated PC3 cells suggest the induction of apoptosis through nuclear and mitochondrial pathways. Hoechst and rhodamine assays confirmed the nuclear condensation and disruption of mitochondrial membrane potential in the cells. B2 also demonstrated inhibitory effects on motility and colonies of PC3 cells at its subcytotoxic concentrations. It is noteworthy that B2 displayed negligible toxicity against the normal cells. Chemometric analysis revealed high content of essential oils, hydrocarbon, fatty acids, esters, and aromatic sesquiterpenes in B2. This study highlights the therapeutic potentials of SC-CO₂ extract of cat's whiskers in targeting prostate carcinoma.Fouad Saleih R. Al-Suede, Mohamed B. Khadeer Ahamed, Aman S. Abdul-Majid, Hussin M. Baharetha, Loiy E.A. Hassan, Mohd Omar A. Kadir, Zeyad D. Nassar and Amin M.S. Abdul Maji
Frequency Compensation of High-Speed, Low-Voltage CMOS Multistage Amplifiers
No full textAamir SA, Harikumar P, Wikner JJ. Frequency Compensation of High-Speed, Low-Voltage CMOS Multistage Amplifiers. In: 2013 IEEE International Symposium on Circuits and Systems (ISCAS2013). Piscataway, NJ: IEEE; 2013: 381-384.This paper presents the frequency compensation of high-speed, low-voltage multistage amplifiers. Two frequency compensation techniques, the Nested Miller Compensation with Nulling Resistors (NMCNR) and Reversed Nested Indirect Compensation (RNIC), are discussed and employed on two multistage amplifier architectures. A four-stage pseudo-differential amplifier with CMFF and CMFB is designed in a 1.2 V, 65-nm CMOS process. With NMCNR, it achieves a phase margin (PM) of 59° with a DC gain of 75 dB and unity-gain frequency (fug) of 712 MHz. With RNIC, the same four-stage amplifier achieves a phase margin of 84°, DC gain of 76 dB and fug of 2 GHz. Further, a three-stage single-ended amplifier is designed in a 1.1-V, 40-nm CMOS process. The three-stage OTA with RNIC achieves PM of 81°, DC gain of 80 dB and fug of 770 MHz. The same OTA achieves PM of 59° with NMCNR, while maintaining a DC gain of 75 dB and fug of 262 MHz. Pole-splitting, to achieve increased stability, is illustrated for both compensation schemes. Simulations illustrate that the RNIC scheme achieves much higher PM and fug for lower values of compensation capacitance compared to NMCNR, despite the growing number of low voltage amplifier stages
Spectrum Sensing Implementations for Software Defined Radio in Simulink
No full textAbstractThe lack of spectrum for communication and for research is a bottleneck as far as technology and business development is considered. It is a fact that the availability of useful spectrum is limited by hardware constraints. The studies conducted by the Federal Communications Commission found that that there are many areas of the radio spectrum which are not fully utilized in different geographical areas of the country and FCC recommended locating and utilizing these unused spectrum spaces by other users. This is where spectrum sensing comes into use. From then on different spectrum sensing algorithms were developed. The paper implements four of those major sensing spectrum algorithms in MATLAB-Simulink and also does a performance comparison among the
Adjunctive treatment with oral AKL1, a botanical nutraceutical, in chronic obstructive pulmonary disease
No full textClaire Brockwell,1 Sundari Ampikaipakan,1,2 Darren W Sexton,1 David Price,3,4 Daryl Freeman,5 Mike Thomas,6 Muzammil Ali,4 Andrew M Wilson1,21Norwich Medical School, University of East Anglia, Norwich, UK; 2Norfolk and Norwich University Hospital Foundation Trust, Norwich, UK; 3Academic Primary Care, University of Aberdeen, Aberdeen, UK; 4Research in Real Life, Cambridge, UK; 5Mundesley Medical Centre, Mundesley, Norwich, UK; 6Primary Care Research, Aldermoor Health Centre, University of Southampton, Southampton, UKPurpose: The objective of this pilot trial was to evaluate the safety and efficacy of AKL1, a patented botanical formulation containing extracts of Picrorhiza kurroa, Ginkgo biloba, and Zingiber officinale, as add-on therapy for patients with chronic obstructive pulmonary disease (COPD) and chronic cough.Patients and methods: This randomized, double-blind, placebo-controlled trial enrolled male and female patients >18 years old with COPD and Leicester Cough Questionnaire (LCQ) score of <18. The 10-week study period comprised a 2-week single-blind placebo run-in period followed by add-on treatment with AKL1 or placebo twice daily for 8 weeks. The primary study endpoint was the change from week 0 to week 8 in cough-related health status, as assessed by the LCQ.Results: Of 33 patients enrolled, 20 were randomized to AKL1 and 13 to placebo. Patients included 19 (58%) men and 14 (42%) women of mean (standard deviation [SD]) age of 67 (9.4) years; 15 (45%) patients were smokers and 16 (49%) were ex-smokers. The mean (SD) change from baseline in LCQ score at 8 weeks was 2.3 (4.9) in the AKL1 group and 0.6 (3.7) in the placebo group, with mean difference in change of 1.8 (95% confidence interval: –1.5 to 5.1; P=0.28). The St George's Respiratory Questionnaire score improved substantially in the AKL1 treatment group by a mean (SD) of –7.7 (11.7) versus worsening in the placebo group (+1.5 [9.3]), with mean difference in change of –9.2 (95% confidence interval: –19.0 to 0.6; P=0.064). There were no significant differences between treatment groups in change from baseline to week 8 in other patient-reported measures, lung function, or the 6-minute walk distance.Conclusion: Further study is needed with a larger patient population and over a longer duration to better assess the effects of add-on therapy with AKL1 in COPD.Keywords: Leicester Cough Questionnaire, anti-inflammatory, Picrorhiza kurroa, Ginkgo biloba, Zingiber officinal
Is M&A Self-Dealing in the Context of Peer Benchmarking of CEO Pay?
No full textWe define two effects: (a) percentage difference between median CEO pay of compensation peers and their counterfactual peers (Peer pay effect, PPE), and (b) percentage difference between focal firm CEO pay and the median CEO pay of their compensation peers (CEO pay effect, CPE). We find a negative relation between M&A announcement period abnormal returns and pre-announcement PPE. The PPE (CPE) is lower (higher) in acquiring years relative to non-acquiring years. We show that the lower PPE is consistent with better governance and higher CPE is due to benchmarking against peers with higher median CEO pay and for completing acquisitions
Dependence of critical micelle concentration of a zwitterionic detergent on ionic strength: implications in receptor solubilization
No full textAbstractThe zwitterionic detergent, 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS), is mild, non-denaturing, and extensively used for solubilizing membrane proteins and receptors. We report here that the critical micelle concentration (CMC) of CHAPS is dependent on the concentration of NaCl in the solution. Thus, the CMC of CHAPS decreases from 6.41 mM in absence of any salt to 4.10 mM in presence of 1.5 M NaCl. The logarithm of the CMC values appear to have a linear relationship with the salt concentration. Such changes in CMC with ionic strength have important implications in solubilization of membrane-bound neuronal receptors. This is shown by optimal solubilization of the serotonin receptor type 1A (5-HT1A) from bovine brain hippocampal crude (native) membrane by CHAPS at premicellar concentration under high salt conditions
Code Converters with City Block Distance Measures for Classifying Epilepsy from EEG Signals
No full textAbstractThis paper aims to compare the performance of code-converter as a feature extraction technique followed by various distance measures such as City Block Distance (CBD) measure and Euclidean Distance (ED) measure for the perfect classification of epilepsy risk levels from Electroencephalography (EEG) Signals. From the extracted parameters such as sharp and spike waves, energy, peaks, duration, variance, events and covariance from the EEG Signals of an epileptic patient, the risk level of epilepsy is classified. The City Block Distance Measure and Euclidean Distance Measure is then applied to the Code Converter's risk level classification output in order to optimize the risk levels for the characterization of the patient. In this study, a group of 10 patients with known epilepsy findings are utilized here. The Performance metrics is computed with the help of parameters like Performance Index (PI) and Quality Values (QV)
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