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Dynamic power and bandwidth allocation for DVB-based LEO satellite systems
Satya Chan(Satya Chan),Gyuseong Jo(Gyuseong Jo),Sooyoung Kim(Sooyoung Kim),Daesub Oh(Daesub Oh),Bon-Jun Ku(Bon-Jun Ku) 한국전자통신연구원 2022 ETRI Journal Vol.44 No.6
A low Earth orbit (LEO) satellite constellation could be used to provide network coverage for the entire globe. This study considers multi-beam frequency reuse in LEO satellite systems. In such a system, the channel is time-varying due to the fast movement of the satellite. This study proposes an efficient power and bandwidth allocation method that employs two linear machine learning algorithms and take channel conditions and traffic demand (TD) as input. With the aid of a simple linear system, the proposed scheme allows for the optimum allocation of resources under dynamic channel and TD conditions. Additionally, efficient projection schemes are added to the proposed method so that the provided capacity is best approximated to TD when TD exceeds the maximum allowable system capacity. The simulation results show that the proposed method outperforms existing methods.
Effect of melatonin on the onset of puberty in male juvenile rats
Satya Prasad Venugopal,Satya Prasad Venugopal 대한해부학회 2019 Anatomy & Cell Biology Vol.52 No.3
Melatonin or N-acetyl-5-methoxytryptamine, the fascinating molecule secreted by the pineal gland. Melatonin has a close interaction with hypothalamic-pituitary-gonadal axis. In non-seasonal breeders like rat its exact role in reproduction is controvertible. So it is worth to explore the possible role of melatonin on the onset of puberty in male albino rats. Two groups of male rats aged 5 and 10 days were used for the study. In each group, there were three subgroups, each receiving melatonin for 5 days, 10 days or till the day of descent of testes. Similar subgroups were used as controls. Without handling, animals were observed daily for the onset of puberty. On the day of descent of testes, body weight of the animal was noted, blood was collected, serum was separated and used for radio immunoassay. For histomorphometric analysis, all morphometric measurements were done using an occular micrometer. Volume fraction of seminiferous tubules, intertubular connective tissue of testes, cortex and medulla of thymus were estimated by point count method. In both the age groups melatonin advanced the age on descent of testes, increased the body weight, organ weight. It also increased the serum hormone levels. So, in conclusion this study indicates that exogenous melatonin advances the onset of puberty in male albino wistar rats and this effect is more pronounced in the younger animals.
Physics based modelling and analysis of IPMC vibration energy harvester
Satya Narayan Patel,Sujoy Mukherjee 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8
Advancement in smart materials and decrease in power requirement of electronic devices motivates researchers to use smart materials for energy harvesting applications. In this study, a physics-based modelling approach by considering the effect of convective transport on cation migration and the effect of local deformation on anion concentration is used to model IPMC based vibration energy harvester and solved with the help of COMSOL Multiphysics 5.5 finite element method. The present harvester model voltage and power output under fixed load resistance, and power output under variable load resistance for both excitation frequencies (2 Hz and 5 Hz) and both excitation amplitudes (3 mm and 5 mm) are analysed by both FEM and experimental results. At 5 Hz and 5 mm excitation amplitude and frequency, the peak voltage is 171.9 mV, and the peak power is 60.48 nW for 2 Hz excitation and 5 mm amplitude of mechanical vibration. According to the findings, physics-based modelling can be utilized to develop and analyse IPMC vibration energy harvesters. It will also be useful for analyzing IPMC-based sensors and actuators.
Satya Prakash,Milap Chand Sharma,Rajesh Kumar,P. S. Dhinwa,K. L. N. Sastry,A. S. Rajawat 대한공간정보학회 2016 Spatial Information Research Vol.24 No.6
Land degradation is a major problem in the fragile ecosystem of the Himalayan region. The steep slope with low forest cover and increasing human interference are the major factors of land degradation. Therefore, identification of severe degradation prone areas is necessary for implementing conservation strategies to retard the present rate of degradation processes. The aim of this study is to assess the vulnerable land degradation areas based on Space Application Centre (SAC/ISRO) guidelines and MEDALUS model. Indicators used to calculate the degradation vulnerability are geology, slope, aspect, soil type, rainfall, temperature, land use/land cover, population density, non-worker population and illiteracy. The results reveal that the areas with higher rainfall, less forest cover and large population are highly vulnerable to degradation in spite of moderate slope. The degradation vulnerability index values have been classified into five land degradation categories. The Pong dam is a large water body where the land degradation is nil. The low, moderate, high and very high land degradation categories account for 19.01, 22.79, 31.49 and 17.37% area of the district, respectively.
Fusion of Medical Images using a Wavelet Methodology: A Survey
Satya Prakash Yadav,Sachin Yadav 대한전자공학회 2019 IEIE Transactions on Smart Processing & Computing Vol.8 No.4
Image compression or fusion is the concept of identifying in-depth parameters of disease variables, and requires output images that preserve all the viable and prominent information that is gathered from source images without any further introduction of artifacts or unnecessary distortions. Measurement of images for prospective evaluation and image fusion depends on various performance measures, such as structure similarity index, standard deviation, edge detection, correlation coefficient and high pass correlation, average gradient, root-mean-square error, peak signal-to-noise ratio, entropy, etc. This review discusses various medical image fusion modalities focused on Principal Component Analysis, Independent Component Analysis, and wavelet transform. An introduction to the usefulness of such modalities is presented, suggesting safe hybrid modality combinations that could greatly enhance the image fusion process. Novel trends in medical image fusion techniques to achieve a perfectly desired, quality image, the future prospects of an ideal technique for medical imaging, and recognition of diseases are covered.
Study on the Gilbert damping of polycrystalline YIG films with different capping layers
Satya Prakash Pati 한국물리학회 2020 Current Applied Physics Vol.20 No.1
This paper describes the effect of 5-nm thick platinum (Pt), aluminum (Al) and silicon oxide (SiOx) capping layers on the static and dynamic magnetic properties of 400-nm thick polycrystalline YIG films deposited on a Pt buffer layer. Both static and dynamic magnetic properties of Pt capped YIG film are totally different among all YIG films. Namely, the squareness of the magnetization curve for Pt capped YIG film increases, indicating that Pt capped YIG film is magnetically softer than other YIG films. Interestingly, the effective Gilbert damping parameter of Pt capped YIG films is about four times as large as those of other YIG films, and its value is approximately 9.52×10−4. However, the value of Gilbert damping is 2.55×10−4, 3.46×10−4 and 3.85×10−4 respectively for no capping, SiOx capping and Al capping samples respectively. This huge change in Gilbert damping parameter is mainly originating from the spin pumping effect, which arises at the interface of a material having strong spin orbit interaction such as Pt. Moreover, the enourmous increase in the value of effective anisotropic field and decrese in effective saturation magnetization indicates interface anisotropy is induced in Pt capped sample. These results suggest that the static and dynamic magnetic properties of YIG film can be controlled by selecting an appropriate capping layer.