Trough Points Research Articles

A graphical method and workflow for the generation of structure contours for horizontal cylindrical folds

A graphical method developed for the construction of structure contours for inclined planar surfaces has been extended to curved or folded surfaces with cylindrical geometries and horizontal axes. These structure contours can be used to constrain the outcrop trace of a folded contact on a geological map. The extended method requires, as a minimum, a field of orientation data and the map position of a single elevation on the contact under investigation. The method utilises orientation data collected on and around a partially mapped trace of a folded contact to constrain the outcrop trace throughout a geological map. The method uses a vertical cross-section that is parallel to the profile plane of any folds present. Crest, trough and hinge points identified in the cross-section can be projected on to the geological map in their correct positions and elevations. Similarly, structure contours on fold axial surfaces can be projected on to the geological map and the contours used to locate the axial traces of cylindrical folds with horizontal axes.

Solar Hybrid System: Innovations in Cooking, Drying, and Power Generation

A hybrid system has been designed and developed which comprises the principle of solar thermal and photovoltaic. Flat plate collector and concentrating trough collector were incorporated under solar thermal technology. Solar thermal device which makes the most using infrared radiation out of solar spectrum. Black copper sheet at focal point of the solar trough served as a stand for cooking pan was able to gain direct as well as high intensity reflected solar radiation to expedite the cooking process. The electric unit of the system worked on the principle of photovoltaic effect. Main components of the hybrid system were collector housing, solar trough reflector, triangular shaped glazing surfaces, copper sheet to place cooking pots and dedicated insulation to prevent heat loss. The dual concept hybrid system was found exceptionally speedier as compared to traditional box type cooker. Results revealed that cooking pot attained maximum temperature of 104.50 C at 12.30 pm, which was sufficient for cooking nutritious food. The experiment was conducted in winter season on 18th January, 2018. Average thermal efficiency (ηtherm) was estimated as 35.1%, cooking power (P) was estimated 47.68 W and the overall heat loss coefficient was calculated 3.03 W/m2°C. Average cooking time found to be just 130 minutes which was otherwise more than 3 hrs in case of traditional box type cooker. Electric power which was stored in the battery can operate 5W dc bulb for 9 hours in single charging. It also could operate smart phone charger and a dc fan (12V, 4Ah) for 60 minutes each.

Ad libitum feeding systems for lactating sows: effects on productivity and welfare of sows and piglets

The nutritional requirements of sows change during lactation and thus require adapted and dynamic feeding regimes that consider the sows’ behavioral needs and production traits. The present study evaluated the effect of four different feeding systems on productivity and aspects of the welfare of 61 sows and their piglets during lactation. A non-ad libitum system (CON) was compared with two computer-monitored (COMP, COMP + ) ad libitum feeding systems, that allowed sows to access feed via displacement of an electronic sensor, as well as a third purely mechanical ad libitum feeding system (MECH). Daily feed disappearance, piglet growth, piglet growth per feed disappearance as well as sows’ weight and conception rate were recorded. Health indicators of sows and piglets were scored as well as sow behavior analyzed for a total of 96 hours/sow from video recordings taken on days 2–4 and 23 postfarrowing (n = 35 sows). Sows from all three ad libitum systems (COMP, COMP+, MECH) showed a lower feed disappearance than CON (P < 0.01). Additionally, average daily piglet growth tended to be higher (P = 0.05) and piglet growth per sow feed disappearance was significantly higher in all three ad libitum systems than in CON (P < 0.01). Piglet mortality, sow weight loss and subsequent conception rates did not differ between treatment groups. Piglets in COMP and COMP + had fewer head lesions (P = 0.01). Sows in all three ad libitum systems spent more time with their head in the trough than in the non-ad libitum system (P < 0.01). Occurrence of sow stereotypies (vacuum chewing, biting fixtures) was rare (typically < 2% of scans) and did not differ between treatments. Our data suggest that sows fed ad libitum eat what they need and can convert feed more efficiently into the piglets’ growth without additional weight loss. Furthermore, the increased time sows spent in ad libitum systems with their head in the trough points toward longer feeding times, which might be beneficial in terms of meeting pigs’ behavioral need to forage. Taken together, our initial studies on sow feeding behavior and feed efficiency will benefit the development of new lactation feeding systems that promise to improve animal welfare and productivity while reducing feed costs.

The Effects of Caffeine and Alcohol on the Electrically Evoked Responses of L. terrestris

Regulation on animal research, largely focused on vertebrates, has led to greater expenses for researchers and institutions. Invertebrate animals, however, are rarely included in regulatory oversight, making experimentation comparatively more flexible and inexpensive. Yet, invertebrates are largely overlooked in neurophysiological research, even though the simplicity of invertebrate nervous system models has its advantages. While somatosensory, visual, and auditory evoked potential may be used for pharmacological and toxicological assessment of drugs in both animals and humans, only minor research carried out on invertebrates generally due to the disregard upon comparison between physiological phases or chromosomes of both invertebrates and humans. This study aims to analyze the viability of Lumbricus terrestris, or the common earthworm, as a potential model for electrical somatosensory evoked potential propagation and for drug safety pharmacology assessment. Varying intensities of electrical stimulation potential from 45 ~ 137 mV and accumulative substance injections up to 300 ul were to be used to evaluate telemetric-recorded changes in the evoked potential of the earthworm, and to track the extent of its reproducibility. Alcohol and caffeine, as they are two of the most commonly consumed chemicals in beverages among adolescents, and much was already known about their neurological effects, making the earthworm model’s response to foreign substances evaluable. Numerical changes in latent period, peak point, trough point and wave width of the evoked potential elicited by each substance were analyzed using regression analysis. We found that our peak point and wave width evoked potential parameters were highly indicative of the earthworm’s capability as an evoked potential invertebrate model, especially because responses exhibited expected outcomes of the excitable and inhibitory effects of caffeine and alcohol with high reproducibility.

A Quantitative Three-Dimensional Tear Trough Deformity Assessment and Its Application in Orbital Septum Fat Transposition.

Existing evaluation tools of tear trough deformity are based on subjective impression of clinicians. More accurate quantitative assessment methods are needed. This study aimed to propose a quantitative three-dimensional assessment method for the tear trough deformity in comparison with the Barton's grading system and apply it to the efficacy evaluation of orbital septum fat transposition. 117 healthy Chinese adults (234 eyes) were enrolled and divided into four groups according to the Barton's grading system. Three-dimensional facial images were captured using Vectra H1 handheld camera. 6 anthropometric landmarks were identified on each eye and 8 linear measurements were generated accordingly. Intra-observer reliability was determined and measurements were compared between groups. Pre- and post-operative three-dimensional measurements were compared in 19 patients who received lower blepharoplasty with orbital septum fat transposition. The severity of tear trough was positively correlated with age (P < 0.001) but not BMI (P = 0.145) or gender (P = 0.280). Intra-rater reliability of the 8 linear measurements was excellent except for the vertical distance between the palpebrale inferioris margin and the tear trough below the pupillary center. Intergroup comparison showed that the horizontal distance between the lateral end of tear trough (P < 0.001) and medial canthus and the sagittal vector from tear trough point toward eyelid bag point (P = 0.009) increased with grade, while the vertical distance from mid-pupil to palpebrale inferioris margin decreased gradually (P = 0.001). Orbital septum fat transposition significantly improved the tear trough deformity as assessed by these three-dimensional measurements. We demonstrated a novel quantitative evaluation method of the tear trough deformity using three-dimensional stereophotogrammetry and proved it to be valid and reliable. It showed good value of clinical application and might help with periorbital rejuvenation planning and outcome assessment. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A new theoretical model to locate the back scarp in landslides caused by strength reduction in slip zone soil

The location of the backscarp is important for determining the landslide range. This study aimed to propose a new theoretical model for calculating the location of the backscarp in landslides caused by strength reduction in slip zone soil. The new theoretical model was first presented based on a two-surface failure mechanism, which specifically means that the strength reduction in slip zone soil first generates a basic slip surface and eventually generates a backscarp. Then, nine landslide experiments were performed to validate the theoretical model, and the locations of backscarps in the nine experiments were calculated. Finally, the theoretical model was applied to three real landslides (Xierguazi, Jiangdingya, and Xibuding landslides). The calculations show that for each of the experimental and real landslides, there is a trough point at which the local lowest factor of safety attains its lowest value, which corresponds to the inclination of the critical backscarp, indicating that the critical backscarp is readily located by the theoretical model. Moreover, the location of the calculated critical backscarp generally agrees with that of the measured or published backscarp for each of the experimental and real landslides.

Analysis of outlet temperature of parabolic trough collector solar water heater using machine learning techniques

The green sources of energy are ocean, hydro, solar, tidal, wave, wind, biomass, etc. Among all these wind, solar and hydro are mainly used. Particularly, solar energy has various applications such as atmospheric energy balance studies, solar energy collecting systems, analysis of the thermal load on buildings, etc. Parabolic trough collector (PTC) based solar water heater (SWH) gains a significant role in water heating systems. Parabolic trough collector is a concentrating type collector which collects the solar radiation in copper tube placed in the focal point of the parabolic trough. It also generates a high temperature which is suitable for steam generation. The main goal of this paper is to predict the outlet temperature of parabolic trough collector solar water heater with time and temperature for different days using various machine learning techniques.

INVESTIGATING THE ACTION POTENTIAL PARAMETERS INDUCED BY A SIMULATED SPINAL CORD COMPRESSION USING A Lumbricus terrestris MODEL

Spinal cord compression is caused when a mass exerts pressure on the cord. The mass usually originates from a growing tumor or bone abnormality. Compression can build up anywhere along the spinal cord, from the neck to the lower spine. Spinal cord compression can also be caused by any condition that puts pressure on the spinal cord, such as if the vertebrae are physically damaged or pressed. Back pain persists anywhere down the leg for common symptoms. Other symptoms include numbness in the toes or fingers or over the buttocks, feeling uncomfortable on your feet or difficulty walking, passing very little urine or being unable to urinate, and loss of bladder or bowel control. Despite this seriousness, not many study models have been documented.&#x0D; This study examined the change of action potential parameters such as latent period, peak point, wave width, and trough point to show any functional relationship according to the increased weight placed on Lumbricus terrestris’ body. The compression of Lumbricus terrestris’ spinal cord by weight standards simulated the growing cancers in the confined spinal space. It concluded that the latent period and trough point were positively correlated, while peak point and wave width were negatively correlated. And the trend of parameter changes seemed to be consistent. Moderate changes were shown for all the parameters concerning weight load on the spine. Further study might be warranted for detailed understanding the underlying mechanism of the parameter profiles.

Potency of the pandemic on air quality: An urban resilience perspective

Since the outbreak of COVID-19 pandemic, the lockdown policy across the globe has brought improved air quality while fighting against the coronavirus. After the closure, urban air quality was subject to emission reduction of air pollutants and rebounded to the previous level after the potency period of recession. Different response patterns exhibit divergent sensitivities of urban resilience in regard to air pollution. In this paper, we investigate the post-lockdown AQI values of 314 major cities in China to analyse their differential effects on the influence factors of urban resilience. The major findings of this paper include: 1) Cities exhibit considerable range of resilience with their AQI values which are dropped by 21.1% per day, took 3.97 days on average to reach the significantly decreased trough point, and reduced by 49.3% after the lockdown initiatives. 2) Mega cities and cities that locate as the focal points of transportation for nearby provinces, together with those with high AQI values, were more struggling to maintain a good air quality with high rebounds. 3) Urban resilience shows divergent spatial sensitivities to air pollution controls. Failing to consider multi-dimensional factors besides from geomorphological and economical activities could lead to uneven results of environmental policies. The results unveil key drivers of urban air pollution mitigation, and provide valuable insights for prediction of air quality in response to anthropogenic interference events under different macro-economic contexts. Research findings in this paper can be adopted for prevention and management of public health risks from the perspective of urban resilience and environmental management in face of disruptive outbreak events in future.

Vibration responses characteristics of a Ginkgo biloba tree excited under harmonic excitation.

The most effective method of the fruit harvesting is the mechanical harvest. The frequency spectrum of different testing positions on a Ginkgo biloba tree under the impact excitation was tested in the laboratory. The acceleration responses under the harmonic excitation were measured at the frequency of the peak and trough points in the frequency spectrum curves. Results of this research indicate that the frequency spectrum presented the consistency on the same branch but distinction among different branches. There was a correspondence between the frequency spectrum characteristics and the vibration responses. The vibration responses could be strengthened at the resonant frequency. Merely, the acceleration responses at low frequency were very weak. At higher frequency, the vibration responses were strong but presented different characteristics among different branches. The acceleration response on the trunk was always the weakest. On the same branch, the dynamic responses presented the similar characteristics and the acceleration amplitude increased gradually as the testing position was located away from the excitation point on the trunk. Among different branches, the strongest dynamic response appeared at different frequencies. Our results indicate that it was difficult to induce the strong vibration response of all the branches at the single frequency during the practical mechanical harvesting of fruits.

High-Trough Plasma Concentration of Afatinib Is Associated with Dose Reduction.

Simple SummaryAfatinib is used to treat non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutation as a second-generation EGFR-tyrosine kinase inhibitor (TKI). We examined the relationship between the trough plasma concentrations of afatinib and adverse effects, including diarrhea, rash, stomatitis and mucositis. The dose reduction of afatinib was associated with the trough plasma concentration of afatinib in this paper. As a result, we clarified that a higher trough plasma concentration induced adverse events, and there was a threshold to reduce the dosage or not. Monitoring plasma concentrations of afatinib is useful to predict the adverse effects of afatinib and to support quality of life in patients with EGFR-mutated advanced NSCLC.Afatinib is used to treat non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutation as a second-generation EGFR-tyrosine kinase inhibitor (TKI). Early prediction of adverse effects based on the pharmacokinetics of afatinib enables support for quality of life (QOL) in patients with no change in efficacy. We examined the pharmacokinetic relationship between trough plasma concentration and adverse effects and evaluated the utility of measuring the trough plasma concentration of afatinib as the first EGFR-TKI treatment for NSCLC in a prospective multicenter study. Twenty-four patients treated with afatinib were enrolled in this study. All blood samples were collected at the trough point, and plasma concentrations were measured using high-performance liquid chromatography–tandem mass spectrometry. Logistic regression analysis for the dose reduction of afatinib was performed, and the receiver operating characteristic (ROC) curve was plotted. Although all patients started afatinib at 40 mg/day, plasma concentrations were variable, and mean and median trough plasma concentrations were 32.9 ng/mL and 32.5 ng/mL in this study, respectively. Minimum and maximum trough plasma concentrations were 10.4 ng/mL and 72.7 ng/mL, respectively. This variability was speculated to involve personal parameters such as laboratory data. However, no patient characteristics or laboratory data examined correlated with the trough plasma concentration of afatinib, except albumin. Albumin showed a weak correlation with plasma concentration (r = 0.60, p = 0.009). The trough plasma concentration of afatinib was significantly associated with the dose reduction of afatinib (p = 0.047). The area under the ROC curve (AUC) for the trough plasma concentration of afatinib was 0.81. The cut-off value was 21.4 ng/mL. The sensitivity and specificity of the cut-off as a risk factor were 0.80 and 0.75. In summary, the trough plasma concentration of afatinib was associated with continued or reduced dosage because of the onset of several adverse effects, and a threshold was seen. Adverse effects not only lower QOL but also hinder continued treatment. Measuring plasma concentrations of afatinib appears valuable to predict adverse effects and continue effective therapy.

Influence of COVID-19 Lockdowns on the Usage of a Vision Assistance App Among Global Users With Visual Impairment: Big Data Analytics Study.

BackgroundMillions of individuals with visual impairment use vision assistance apps to help with their daily activities. The most widely used vision assistance apps are magnifier apps. It is still largely unknown what the apps are used for. Lack of insight into the visual needs of individuals with visual impairment is a hurdle for the development of more effective assistive technologies.ObjectiveThis study aimed to investigate how needs for visual aids may vary with social activities, by observing the changes in the usage of a smartphone magnifier app when many users take breaks from work.MethodsThe number of launches of the SuperVision Magnifier app was determined retrospectively from 2018 to 2020 from among active users worldwide. The fluctuation in app usage was examined by comparing weekday vs weekend periods, Christmas and new year vs nonholiday seasons, and COVID-19 lockdowns vs the easing of restriction during the pandemic.ResultsOn average, the app was used 262,466 times by 38,237 users each month in 2020 worldwide. There were two major trough points on the timeline of weekly app usage, one aligned with the COVID-19 lockdowns in April 2020 and another aligned with the Christmas and new year week in 2018 and 2019. The app launches declined by 6947 (11% decline; P<.001) during the lockdown and by 5212 (9% decline; P=.001) during the holiday weeks. There was no significant decline during March to May 2019. App usage compensated for seasonal changes was 8.6% less during weekends than during weekdays (P<.001).ConclusionsThe need for vision assistance technology was slightly lower during breaks and lockdowns, probably because the activities at home were different and less visually demanding. Nevertheless, for the entire user population, the needs for visual aids are still substantial.

Diagnosis system of sleep apnea based on wearable sensor

Sleep Apnea Syndrome (SAS) is a serious threat to the life and health of patients. In this paper, a breathing coil is used as a flexible sensor, and a breathing signal conditioning circuit is designed to collect breathing signals. At the same time, an algorithm for determining the incidence of apnea is designed. First, all the maximum points in the respiratory signal and the corresponding extreme positions are found; then the cubic spline interpolation function is used to fit the upper and lower values of the maximum and the minimum envelope, and find the average value of the upper and lower envelopes; finally, the peak or trough point by searching for the local minimum or local maximum in the average envelope was found, and then further segmented calculations was performed. The test results show that the misjudgment range between the number of sleep apneas recorded by the simulation experiment and the number of sleep apneas obtained by the algorithm is between -2 and 3 times. The designed system terminal equipment is accurate, comfortable to wear, can be monitored for a long time. And is suitable for family daily sleep monitoring.

Steady-state thermal resistance measurement of light-emitting diodes based on spectroscopic method

According to the luminous spectrum characteristics of white light emission diode (WLED) light emission spectrum, through the analysis of the intersection (the trough point of the whole spectrum) of blue light spectrum and yellow light spectrum generated by blue light excited yellow phosphor, in this paper we design an LED steady-state thermal resistance measurement system based on the spectroscopic method by using the conventional spectrometer, and we also use the normal driving current to fit the whole spectrum trough through a certain function algorithm. According to the temperature rise curve, we can calculate the temperature rise of the LED junction temperature relative to the substrate under any working condition, and combine the heat dissipation power of the LED to get the steady-state thermal resistance of the LED. This method avoids the limitation of a similar forward voltage drop method which uses the minimum current calibration and requires the modules of high-speed data acquisition and high-speed sampling conversion, thus making the equipment expensive. Therefore it is necessary to reduce its cost. Finally, the system designed in this paper and the T3Ster instrument of Mentor Graphics Corporation in the United States are both used to measure various LEDs and their results are compared with each other. The results show that the maximum deviation of steady-state thermal resistance is only 3.64%. It indicates that the system and method designed in this paper can achieve the same precision as T3Ster instrument of Mentor Graphics Corporation, demonstrating that the system and method designed in this paper can achieve the same precision as the T3Ster instrument of Mentor Graphics, under the condition without needing expensive equipment, Moreover, this method uses non-traditional spectral method to measure the junction temperature of LED, which has the characteristics of remote real-time online detection of LED junction temperature, low cost, and no restrictions on the LED packaging structure. Therefore, this method has a wider application range than the voltage method adopted by Mentor Graphics T3Ster equipment, and has a certain practical value.

Dynamic effects of shadow economy and environmental pollution on the energy stock prices: empirical evidence from OECD countries.

This study investigates the dynamic effects of the shadow economy and environmental pollution on the energy stock prices in the case of the Organization for Economic Co-operation and Development (OECD) countries via generalized methods of moments (GMM) and during the years from 2004 to 2014. Results suggest significant links between the volume of shadow economies, energy stock prices, and environmental pollution. Negative effects of carbon dioxide emissions on energy stock prices are found in this study. Furthermore, a U-shaped relationship is also found between the shadow economy and energy stock prices; that is the initial levels of the shadow economy the response of energy stock prices is negative; then, beyond a trough point, its response starts to be positive at the further stages of the level of shadow economies. Despite energy consumption raises energy stock prices, environmental pollution mitigates the value of energy stock prices.

Intensity Factor Method for Segmenting Human Body Region in Gray-scale Infrared Image

The normalized intensity factor based on statistical first-order moment of gray-scale image is defined in this paper. The intensity factor can be used to distinguish the brightness level of a gray-scale image and to determine a threshold value for image segmentation. According to the intensity factor and the characteristic of human body in the gray-scale infrared image, a new algorithm of calculating the intensity-level threshold is designed which can be used for segmenting human body area in an infrared image. In the algorithm, based on the concept of intensity factor, a histogram of low brightness gray-scale image (LGIRI) is divided into three parts: a low-intensity region (0.25[Formula: see text][Formula: see text]), a medium-intensity region (0.25–0.75[Formula: see text][Formula: see text]), and a high-intensity region (0.75–1[Formula: see text][Formula: see text]), and then the intensity [Formula: see text] which satisfies the [Formula: see text] is selected as an intensity-level value [Formula: see text], and the intensity [Formula: see text] which satisfies [Formula: see text] is selected as an intensity-level value [Formula: see text], at last [Formula: see text] is the pixel classification threshold (the intensity-level threshold). It is noted that there is no preprocessing for image noise filtering and/or processing, and all images come from OTCBVS. Compared with the method of selecting trough points of the histogram as the intensity-level threshold, this algorithm avoids the problem of nonexistence of evident trough point at the high-intensity level of a histogram. Also, the experimental results show that the segmenting results of LGIRI processed by the algorithm are better than those of Otsu method.

The vibrational response of simulated Ginkgo biloba fruit based on their frequency spectrum characteristics.

The most effective method for harvesting forest fruit is the mechanical vibration harvesting method. During the forced vibration process, the fruit will be shed from the tree when the inertia of the fruit is greater than the fruit’s pedicel retention force. In order to study the movement response characteristics of the Ginkgo biloba fruit in depth, for a small Ginkgo biloba fruit tree, the frequency curve of the fruit tree had been obtained in this paper, based on the pulse hammer excitation method, and four resonant frequencies and four trough point frequencies, in the frequency range of 10 Hz~25 Hz, were determined as the test excitation frequency. Through a comparison test between the simulated fruit and the Ginkgo biloba fruit, both the simulated fruit and the real Ginkgo biloba fruit demonstrated good response consistency, and the results had shown that the simulated fruit could be used to replace the Ginkgo biloba fruit. The acceleration response of the resonant frequency and the trough point frequency for two test points of the two primary branches had also been analyzed. It was found that the resonant frequency caused an obvious harmonic response. For the same frequency, the fruit at some points produced a very strong vibrational response, while at other points the fruit was almost stationary. Therefore, it was difficult for a fruit tree to completely shed all its fruit through excitation at a single frequency. It was more difficult to induce a strong vibrational response of fruit on branches of higher stiffness. On the contrary, it was easier to induce a strong vibrational response on more flexible branches regardless of the resonant frequency or the trough point frequency excitation.

Fourier convolution versus derivative spectrophotometry: Application to the analysis of two binary mixtures containing tamsulosin hydrochloride as a minor component

Simple and rapid spectrophotometric methods are described for determination of two mixtures of tamsulosin (TM), as minor component, with either solifenacin (SL) or tolterodine (TL). The proposed methods involve treatment of the absorbance ratio spectra or zero order spectra by derivative or discrete Fourier function. TM and TL mixture could not be resolved by manipulation of their zero order spectra due to the strong overlap between both spectra and only derivative or Fourier function coefficients of ratio spectra could resolve their spectra. TM and SL mixture was fully resolved by the manipulation of both ratio and zero order spectra. The values of the derivative or the Fourier function coefficients of ratio spectra and/or zero order spectra, at either peak or trough points, were correlated to the concentration of each drug in each mixture. Calibration graphs were linear in ranges 2.5-40 and 30-500μg.mL−1 using derivative ratio and Fourier function ratio, 5-40 and 80–600μg.mL−1 using direct derivative and 2.5–40 and 30–300μg.mL−1 using direct Fourier function for TM and SL, respectively. The plots of derivative ratio amplitude and the Fourier function ratio coefficient versus concentration were linear over ranges 2.5–20 and 25–250μg.mL−1 for TM and TL, respectively. Higher sensitivity as indicated by lower values of detection and quantitation limits were obtained using Fourier convoluted spectra (ratio or zero order) compared to derivative methods. All validation aspects per ICH guidelines are included. The proposed methods were also applied for the studied drugs assay in their tablets and capsules.

Baseline correction algorithm for Raman spectra based on median filtering and un-uniform B-spline

As one of the key steps for data preprocessing of Raman spectra, baseline correction is an effective method to eliminate fluorescence interference. Traditional algorithms such as polynomial fitting and uniform B-spline fitting are simple and easy to implement, but the uncertain fitting order and internal knots limit their flexibility. In addition, the baseline correction results of traditional algorithms often occur over and under fitting phenomena. Therefore, we propose a baseline correction algorithm for Raman spectra based on median filtering and un-uniform B-spline. Firstly, the trough points of the spectral data are filtered by smoothing preprocess, difference calculation and threshold setting, and the internal knots of the un-uniform B-spline are adaptively selected by the trough positions of the spectral data. Then, the median filtering algorithm is used to process the spectral data so that the un-uniform B-spline has a better baseline fitting effect at the position where the signal changes from peak to smooth band. Finally, the un-uniform B-splines is used to fit the baseline by fitting the baseline iteratively. The proposed algorithm overcomes the shortcoming of traditional B-spline algorithm that the internal knots need to be selected manually based on different Raman spectra, and also avoids influencing the baseline fitting by random noise in the spectral data, and thus further improving the spectral baseline correction effect. The original Raman spectra of polymethyl methacrylate and normal octane are used for experimentally evaluating the baseline correction effect. Compared with the results from polynomial fitting, uniform B-spline and adaptive iteratively reweighted penalized least squares algorithms, the experimental results show that the proposed algorithm can well eliminate the Raman signal baseline drift effectively without over or under fitting phenomena, and it can perform better baseline correction for different baseline drift situations. Therefore, the proposed algorithm can provide more accurate and reliable information for the further analysis of spectral data.

Ship Wake Detection in SAR Images via Sparse Regularization

In order to analyse synthetic aperture radar (SAR) images of the sea surface, ship wake detection is essential for extracting information on the wake generating vessels. One possibility is to assume a linear model for wakes, in which case detection approaches are based on transforms such as Radon and Hough. These express the bright (dark) lines as peak (trough) points in the transform domain. In this paper, ship wake detection is posed as an inverse problem, which the associated cost function including a sparsity enforcing penalty, i.e. the generalized minimax concave (GMC) function. Despite being a non-convex regularizer, the GMC penalty enforces the overall cost function to be convex. The proposed solution is based on a Bayesian formulation, whereby the point estimates are recovered using maximum a posteriori (MAP) estimation. To quantify the performance of the proposed method, various types of SAR images are used, corresponding to TerraSAR-X, COSMO-SkyMed, Sentinel-1, and ALOS2. The performance of various priors in solving the proposed inverse problem is first studied by investigating the GMC along with the L1, Lp, nuclear and total variation (TV) norms. We show that the GMC achieves the best results and we subsequently study the merits of the corresponding method in comparison to two state-of-the-art approaches for ship wake detection. The results show that our proposed technique offers the best performance by achieving 80% success rate.