Papers by Keyword: Threshold

Abstract: Semiconductor quantum dots (QDs) exhibit significant potential for laser applications, where a thorough understanding of their optical gain properties and excitonic dynamics is crucial for performance optimization. In this study, state-resolved pump-probe transient spectroscopy was employed to investigate the optical gain and exciton dynamics in CdSe QDs. The results reveal that the gain threshold increases with pumping photon energy, attributed to the competition between surface trapping and intraband relaxation, as well as to the increased biexciton binding energy associated with higher-energy excitonic charge distributions. Notably, the biexciton binding energy reverses from negative to positive values with increasing pump energy, a transition that underpins the observed rise in gain threshold. Additionally, time-resolved decay curves demonstrate accelerated excitonic recombination at higher pump fluences, indicating a greater proportion of biexcitons relative to single excitons. These findings provide valuable insights for tailoring optical gain in quantized nanostructures and optimizing QD-based laser devices.

Abstract: Most of the coal mining in Indonesia that uses the open pit mining method faces serious problems, namely the treatment of acid mine drainage. This constitutes a relatively large volume of wastewater, especially in areas that have rainfall in the range of 2000–4000 mm yearly. Acid mine drainage as acidic wastewater formed during excavation cannot be avoided due to the oxidation process during overburden removal. The acidic wastewater that has formed must be managed strictly and appropriately prior to being released into public waters. There are two methods of treating acid mine wastewater, namely active and passive treatments. Active treatment is generally used more frequently during operations, considering the time, effort, and costs; however, when entering the mine closure period, natural processes must be used at lower costs. Undertaking passive treatment in this area has shown a reduction in the chemical materials used and has enabled a greater amount of wastewater to be managed. The purpose of this research is to describe the active and passive treatment processes in the management of acid mine drainage and to analyze the results of passive treatment in preparation for the mine closure stage. Development of passive treatment by swampy forest system can reduce cost of treatment, naturally process and more environment friendlier by reducing the quicklime materials.

Abstract: EMG signal has a random and stochastic characteristics, so it is difficult to predict the amplitude. Furthermore, the EMG signal depends on the electrodes location. Therefore, a proper muscle selection determines the system's accuracy value. The purpose of this study was to investigate the exact location of the electrodes to improve the accuracy of the wearable hand exoskeleton trainer based on electromyography (EMG) signal control. The main advantage of the results of this study is that the most dominant muscle was found in the development of a wearable hand exoskeleton based on an EMG signal threshold. Therefore, the model can be controlled using a single electrode pair which can further be applied using a low-cost microcontroller. In this study, ten respondents were involved in the data acquisition. The discovery of the dominant muscle was carried out by investigating the dominant EMG signal in three muscles (Abductor pollicis longus, extensor digitorum) that plays a role in the open and close movements of the hand exoskeleton. Dry electrode was used to detect EMG signal activity on the skin surface. The EMG signal was then extracted using the root mean square (RMS) feature. After the evaluation, the results showed that the flexor digitorum superficialis muscle in the rest position produced higher accuracy value than the other muscles, which was 96.63±0.67%. In the implementation, the product of this research can be applied for rehabilitation steps in post-stroke patients which is carried out either in a medical rehabilitation unit or at home independently.

Abstract: Reliability analysis of dense and porous sintered clay-based ceramic was compared using three-parameter Weibull model. The raw and the sintered clay at temperatures 900-1300°C were characterized using XRF and XRD. The raw clay (dense) and clay mixed with cassava starch (porous) were compacted and sintered at 1300°C. Flexural strength of the dense (24.11-46.56MPa) and the porous (13.58-23.26MPa) sintered clay were determined using three-point bending test. The results were analyzed by three-parameter Weibull probability distribution using Minitab 15 software at 95% confidence interval. Scale and threshold parameters of the dense sintered clay were higher than that of the porous sintered clay. However, the Weibull modulus of the porous ceramic was higher than the dense ceramic. The morphology of the porous sintered clay shows a relative distribution of porosity while the dense ceramic shows a random distribution of cracks. Three- parameter Weibull is a suitable tool to model the reliability of dense and porous sintered clays.

Abstract: This paper presents a novel method for skin segmentation in color images using piece-wise linear bound skin detection. Various color schemes are investigated and evaluated to find the effect of color space transformation over the skin detection performance. The comprehensive knowledge about the various color spaces helps in skin color modeling evaluation. The absence of the luminance component increases performance, which also supports in finding the appropriate color space for skin detection. The single color component produces the better performance than combined color component and reduces computational complexity.

Abstract: For multi-target radar track Extraction, the paper proposed a multi-regional threshold method, by setting a plurality of parameters threshold, to determine whether the next time point falls within the threshold based on relevant criteria, then to build the track; further proposed satisfaction law, track was established by the relevant observation points, which the satisfaction function is defined between the associated trace points and set it to the threshold, Through the case of simulation, the model results are given in comparison.

Abstract: Wavelet transform denoising is an important application of wavelet analysis in signal and image processing. Several popular wavelet denoising methods are introduced including the Mallat forced denoising, the wavelet transform modulus maxima method and the nonlinear wavelet threshold denoising method. Their advantages and disadvantages are compared, which may be helpful in selecting the wavelet denoising methods. At the same time, several improvement methods are offered.

Abstract: Thresholding is the greenest and most generally used techniques in image segmentation. This threshold determination can be used to extract various features of the vascular geometry that is used for understanding and analyzing of the image. Our objective is to investigate the influence of the modernization of blood vessel geometry to the threshold image intensity level difference in vessel segmentation. This study included a patient with cerebral aneurysms. We employed three different threshold levels from 200, 400 and 600 in order to determine the influence of the threshold objectively. The flow solution variation on exemplified by wall shear stress (WSS) presents similarity due to the location and magnitude of geometry variation resulting from the different threshold image intensity level and relatively small changes can lead to important dissimilarity in geometry of vessel and flow feature, predominantly in location with an enormous variety of cross sectional area. This is the significance of the understanding of modeling computational simulations of blood flow and can be expressively effected by alterations in geometry different.

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In this paper ,the method of the fluorescence lifetime (FL) in fluorescence optical fiber temperature sensor is used to measure the temperature. During the fluorescence information processing , because of existence of the system noise interference, measurement reliability of fluorescence lifetime has been greatly affected, thereby reducing the temperature measurement precision. This paper presents an improved wavelet threshold de-noising method to signal processing, which improves the signal-to-noise ratio and increases the measurement of fluorescence lifetime precision, reduce the error of temperature measurements at the same time. The experimental results demonstrate that this method is effective.

Abstract: This paper proposed an improved method based on adaptive with threshold wavelet transform denoising, according to image is often affected by noise pollution in the process of acquisition and transmission, compared with the advantages and disadvantages of traditional digital filtering method. It extracts the structure information and details of the image. It can adaptively select wavelet transform of optimal decomposition level and soft threshold to achieve the optimal noise reduction effect. The Simulation results demonstrate that this theory can effectively filter Gaussian noise and Salt and pepper noise, at the same time well protect the image details and achieve better visual effects.