A new simplified and robust Surface Reflectance Estimation Method (SREM) for use over diverse land surfaces using multi-sensor data

Surface reflectance (SR) estimation is the most critical pre-processing step for deriving geophysical parameters in multi-sensor remote sensing. Most state-of-the-art SR estimation methods, such as the vector version of the Second Simulation of the Satellite Signal in the Solar Spectrum (6SV) Radiative Transfer (RT) model, depend on accurate information on aerosol and atmospheric gases. In this study, a Simplified and Robust Surface Reflectance Estimation Method (SREM) based on the equations from 6SV RT model, without integrating information of aerosol particles and atmospheric gasses, is proposed and tested using Landsat 5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper plus (ETM+), and Landsat 8 Operational Land Imager (OLI) data from 2000 to 2018. For evaluation purposes, (i) the SREM SR retrievals are validated against in-situ SR measurements collected by Analytical Spectral Devices (ASD) for the South Dakota State University (SDSU) site, USA (ii) cross-comparison between the SREM and Landsat spectral SR products, i.e., Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) and Landsat 8 Surface Reflectance Code (LaSRC), are conducted over 11 urban (2013-2018), 13 vegetated (2013-2018), and 11 desert/arid (2000 to 2018) sites located over different climatic zones at global scale, (iii) the performance of the SREM spectral SR retrievals for low to high aerosol loadings is evaluated, (iv) spatio-temporal cross-comparison is conducted for six Landsat paths/rows located in Asia, Africa, Europe, and the USA from 2013 to 2018 to consider a large variety of land surfaces and atmospheric conditions, (v) cross-comparison is also performed for the Normalized Difference Vegetation Index (NDVI), the Enhanced Vegetation Index (EVI), and the Soil Adjusted Vegetation Index (SAVI) calculated from both the SREM and Landsat SR data, (vi) the SREM is also applied to the Sentinel-2A and Moderate Resolution Imaging Spectrometer (MODIS) data to explore its applicability, and (vii) errors in the SR retrievals are reported using the Mean Bias Error (MBE), Root Mean Squared Deviation (RMSD) and Mean Systematic Error (MSE). Results depict significant and strong positive Pearson’s correlation (r), small MBE, RMSD, and MSE for each spectral band against in-situ ASD data and Landsat (LEDAPS and LaSRC) SR products. Consistency in SREM performance against Sentinel-2A (r = 0.994, MBE = - 0.009, and RMSD = 0.014) and MODIS (r = 0.925, MBE = 0.007, and RMSD = 0.014) data suggests that SREM can be applied to other multispectral satellites data. Overall, the findings demonstrate the potential and promise of SREM for use over diverse surfaces and under varying atmospheric conditions using multi-sensor data on a global scale

On the description of two-particle transfer in superfluid systems

Exact results of pair transfer probabilities for the Richardson model with equidistant or random level spacing are presented. The results are then compared either to particle-particle random phase approximation (ppRPA) in the normal phase or quasi-particle random phase approximation (QRPA) in the superfluid phase. We show that both ppRPA and QRPA are globally well reproducing the exact case although some differences are seen in the superfluid case. In particular the QRPA overestimates the pair transfer probabilities to excited states in the vicinity of the normal-superfluid phase transition, which might explain the difficult in detecting collective pairing phenomena as for example the Giant Pairing Vibration. The shortcoming of QRPA can be traced back to the breaking of particle number that is used to incorporate pairing. A method, based on direct diagonalization of the Hamiltonian in the space of two quasi-particle projected onto good particle number is shown to improve the description of pair transfer probabilities in superfluid systems.Comment: 9 pages, 7 figure

Design and investigation of scalable multicast recursive protocols for wired and wireless ad hoc networks

The ever-increasing demand on content distribution and media streaming over the Internet has created the need for efficient methods of delivering information. One of the most promising approaches is based on multicasting. However, multicast solutions have to cope with several constraints as well as being able to perform in different environments such as wired, wireless, and ad hoc environments. Additionally, the scale and size of the Internet introduces another dimension of difficulty. Providing scalable multicast for mobile hosts in wireless environment and in mobile ad hoc networks (MANETs) is a challenging problem. In the past few years, several protocols have been proposed to efficient multicast solutions over the Internet, but these protocols did not give efficient solution for the scalability issue. In this thesis, scalable multicast protocols for wired, wireless and wireless ad hoc networks are proposed and evaluated. These protocols share the idea of building up a multicast tree gradually and recursively as join/leave of the multicast group members using a dynamic branching node-based tree (DBT) concept. The DBT uses a pair of branching node messages (BNMs). These messages traverse between a set of dynamically assigned branching node routers (BNRs) to build the multicast tree. In the proposed protocols only the branching node routers (BNRs) carry the state information about their next BNRs rather than the multicast group members, which gives a fixed size of control packet header size as the multicast group size increases, i.e. a good solution to the problem of scalability. Also the process of join/leave of multicast group members is carried out locally which gives low join/leave latency. The proposed protocols include: Scalable Recursive Multicast protocol (SReM) which is proposed using the DBT concepts mentioned above, Mobile Scalable Recursive Multicast protocol (MoSReM) which is an extension for SReM by taking into consideration the mobility feature in the end hosts and performing an efficient roaming process, and finally, a Scalable Ad hoc Recursive Multicast protocol (SARM) to achieve the mobility feature for all nodes and performing an efficient solution for link recovery because of node movement. By cost analysis and an extensive simulation, the proposed protocols show many positive features like fixed size control messages, being scalable, low end to end delay, high packet rate delivery and low normalized routing overhead. The thesis concludes by discussing the contributions of the proposed protocols on scalable multicast in the Internet society

Star-rating evaluation model for rating the energy-efficiency level of android google play apps

The tremendous increase in smartphone usage is accompanied by an increase in the need for more energy. This preoperational relationship between modern technology and energy generates energy-greedy apps, and therefore power-hungry end users. With many apps falling under the same category in an app store, these apps usually share similar functionality. Because developers follow different design and development schools, each app has its energy-consumption habits. Since apps share similar features, an end-user with limited access to recharging resources would prefer an energy-friendly app rather than a popular energy-greedy app. However, app stores do not indicate the energy behavior of the apps they offer, which causes users to randomly choose apps without understanding their energy-consumption behavior. A review of the relevant literature was provided covering various energy-saving techniques. The results gave an initial impression about the popularity of the usage of two power-saving modes where the average usage of these modes did not exceed 31% among the total 443 Android users. To address this issue, we propose a star-rating evaluation model (SREM), an approach that generates a tentative energy rating label for each app. The model was tested on 7 open-source apps to act as a primary evaluation sample. To that end, SREM adapts current energy-aware refactoring tools to demonstrate the level of energy consumption of an app and presents it in a star-rating schema similar to the Ecolabels used on electrical home appliances. As per our results, SREM helped in saving 35% of smartphone energy

Specification languages for embedded systems : a survey

Requirements specification is an important part of the software development process. Use of well developed techniques, tools, and languages during requirements specification is especially crucial for complex embedded software systems. Four langauges appropriate for the specification of software requirements for complex embedded systems (RSL, PAISLey, Statecharts, and SCR) are reviewed in detail here. In addition, other representation languages with features relevant to the embedded software systems domain are mentioned. Conclusions about the current status of embedded systems requirements specification and indications of further research are given

A Review of System Development Systems

The requirements for a system development system are defined and used as guidelines to review six such systems: SAMM, SREM, SADT, ADS / SODA, PSL/PSA and Systematics. It is found that current system development systems emphasise only validation and user verification. They can perform relatively little on automatic file optimisation, process optimisation and maintenance.postprin

Significance and need of powdery mildew control (Microsphaera alphitoides Griff. et Maubl.) in the process of regeneration of the pedunculate oak (Quercus robur L.) stands in the Ravni Srem area

Background and Purpose: Powdery mildew (Microsphaera alphitoides Griff. et Maubl.) was studied from the aspect of its influence on regeneration of the pedunculate oak stands in the Ravni Srem area. Possibility to control the funguswith chemical protection measures was also investigated.During the three-year research period (2006–2008), efficiency of eight fungicides (Microthiol special, Stroby DF, ZATO 50-WG, Cabrio Top, Quadris, Alert S, Duett Ultra, Sabithane) and their influence on the plant growth increase were tested. Material and Methods: The research was conducted on seedlings and juvenile oak plants in a newly regenerated pedunculate oak stand in the southwestern Srem area, in the Vini~na forest section (dept. 15a). Level of plants infection and evaluation of fungicide efficiency were determined by visual evaluation of the presence of powdery mildew on leaves of 25 randomly picked plants within each experimental field. Plant growth elements were determined on the basis of the length of multistage formed shoots and root neck diameter. Results and Conclusion: Suppression of powdery mildew on pedunculate oak seedlings and juvenile oak plants is an important protective measure which is essential for regeneration areas in the period of regeneration cutting. The observed fungicides showed high efficiency in control of the fungus. A biological feature of pedunculate oak to form multistaged shoots by activating terminal buds during the growing season came to the fore. Majority of plants formed 3 or 4 stage growths during the first year. Chemical protection of seedlings from powdery mildew should be conducted in the period of plant growth in height. In such proceedings, the application of fungicides is reduced to minimum and thereby provides a rational seedling protection. In the second and third year of oak development, applied fungicides had little effect. Under a canopy of herbaceous weed species, plants hadmore or less intense growth in height, depending on climatic conditions and the amount of moisture in the soil

Leading-color two-loop amplitudes for four partons and a W boson in QCD

We present the leading-color two-loop QCD corrections for the scattering of four partons and a W boson, including its leptonic decay. The amplitudes are assembled from the planar two-loop helicity amplitudes for four partons and a vector boson decaying to a lepton pair, which are also used to determine the planar two-loop amplitudes for four partons and a Z/γ∗ boson with a leptonic decay. The analytic expressions are obtained by setting up a dedicated Ansatz and constraining the free parameters from numerical samples obtained within the framework of numerical unitarity. The large linear systems that must be solved to determine the analytic expressions are constructed to be in Vandermonde form. Such systems can be very efficiently solved, bypassing the bottleneck of Gaussian elimination. Our results are expressed in a basis of one-mass pentagon functions, which opens the possibility of their efficient numerical evaluation