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We herein formulate the concept of a generalized lock-in amplifier for the precision measurement of high frequency signals based on digital cavities. Accurate measurement of signals higher than 200 MHz using the generalized lock-in is demonstrated. The technique is compared with a traditional lock-in and its advantages and limitations are discussed. We also briefly point out how the generalized lo
MOD17A2 provides operational gross primary production (GPP) data globally at 1 km spatial resolution and 8-day temporal resolution. MOD17A2 estimates GPP according to the light use efficiency (LUE) concept assuming a fixed maximum rate of carbon assimilation per unit photosynthetically active radiation absorbed by the vegetation (epsilon(max)). Minimum temperature and vapor pressure deficit derive
The use of Penman-Monteith (PM) equation in thermal remote sensing based surface energy balance modeling is not prevalent due to the unavailability of any direct method to integrate thermal data into the PM equation and due to the lack of physical models expressing the surface (or stomatal) and boundary layer conductances (g(S) and g(B)) as a function of surface temperature. Here we demonstrate a
• It is well established that individual organisms can acclimate and adapt to temperature to optimize their functioning. However, thermal optimization of ecosystems, as an assemblage of organisms, has not been examined at broad spatial and temporal scales. • Here, we compiled data from 169 globally distributed sites of eddy covariance and quantified the temperature response functions of net ecosys
This study investigated patterns and controls of the seasonal and inter-annual variations in energy fluxes (i.e., sensible heat, H, and latent heat, lambda E) and partitioning of the water budget (i.e., precipitation, P; evapotranspiration, ET; discharge, Q; and soil water storage, Delta S) over five years (2001-2005) in a boreal oligotrophic fen in northern Sweden based on continuous eddy covaria
Det har skrivits mycket om Karen Blixen genom åren, både av danska, svenska och engelsktalande författare. Hennes liv och författarskap har fascinerat många, så även mig. I min uppsats kommer jag att ta fasta på några frågeställningar med anknytning till Den afrikanske farm. Ett syfte är att belysa genreproblematiken, och svårigheten att sätta in Den afrikanske farm i något av de vedertagna genre
We propose a new class of high-rate spatially coupled LDPC (SC-LDPC) codes based on the convolutional selforthogonal codes (CSOCs) first introduced by Massey. The SCLDPC codes are constructed by treating the irregular graph corresponding to the parity-check matrix of a systematic rate R=(n-1) / n CSOC as a convolutional protograph. The protograph can then be lifted using permutation matrices to ge
When the polar vortex meanders and shifts towards the equator, air masses from the tropics and subtropics can be transported towards the pole in so-called tropical-subtropical streamers. These large-scale structures are areas of low potential vorticity and high pressure, containing dry air with high ozone mixing ratios. The presence of these streamers can also be seen in changes in stratospheric o
Streaming applications are often described using dataflow actor models with a fixed network structure, allowing for static analysis and efficient hardware implementation. However, this fixed structure hinders scalability and design space exploration. This article investigates a representative dataflow toolchain, the StreamBlock compiler for the CAL actor language, along with its Actor Machine (AM)
2023 marks the year when the UIA World Congress Copenhagen event turns the Øresund Region into the epicenter of global debate on architecture’s capacity to reimagine the transformation of societies into sustainable living. Celebrating this manifestation, which will commence on both sides of the Sound, LAS23 will utilize the New European Bauhaus’ three concepts -- sustainability, aesthetics, inclus
The hardware accelerated ray-tracing pipeline presents many opportunities to implement more advanced rendering algorithms than earlier rasterization based approaches. However, one particular aspect of the pipeline still remains a bit too costly to use in practice: The AnyHit-shader. Opacity Micromaps were introduced to alleviate this issue, but the central problem of calling arbitrary shader code
We show that a generalization of the DAG-like query-to-communication lifting theorem, when proven using sunflowers over non-binary alphabets, yields lower bounds on the monotone circuit complexity and proof complexity of natural functions and formulas that are better than previously known results obtained using the approximation method. These include an nΩ(k) lower bound for the clique function up
A proof system P is said to be automatable in time f(N) if there exists an algorithm that given as input an unsatisfiable formula F outputs a refutation of F in the proof system P in time f(N), where N is the size of the smallest P-refutation of F plus the size of F. Atserias and Bonet (ECCC 2002), observed that tree-like k-DNF resolution is automatable in time Nc·k log N for a universal constant
Mobile, near-source measurements are broadly used for determining δ13CH4 of individual methane (CH4) emissions sources. To answer the need for robust and comparable measurement methods, we aim to define the best practices to determine isotopic signatures of CH4 sources from atmospheric measurements, considering instrument accuracy and precision. Using the Keeling and Miller-Tans methods, we verify
Cutting edge preparation is crucial in metal cutting as the edge geometry significantly influences both the material removal process and tool life. However, an analytical model that can physically describe the cutting edge preparation process has not yet been established. Taking the wet abrasive jet machining (WAJM) method as an example, the following questions always remain: Why does WAJM always
Vindkraften spelar en avgörande roll i den gröna omställningen. Men vad händer när vindkraftverken nått slutet av sin livslängd? Tornen som består av enorma mängder stål återbrukas i vissa fall efter renovering men efter två–tre gånger sätter de strukturella förutsättningar stopp för återbruk och torndelarna i stål smälts oftast om till ”nytt stål”. En process som kräver mycket energi och resulterClimate change is a fact, new innovations and solutions need to be applied to mitigate the effects around the world. Greenhouse gases from burning fossil fuels are the primary cause of climate change, one of them being carbon dioxide. There are many attempts to make a turn-around regarding the use of fossil fuels and one of them is wind power. However, due to extreme loads their service life is ju
Certifying solvers have long been standard for decision problems in Boolean satisfiability (SAT), allowing for proof logging and checking with very limited overhead, but developing similar tools for combinatorial optimization has remained a challenge. A recent promising approach covering a wide range of solving paradigms is pseudo-Boolean proof logging, but this has mostly consisted of proof-of-co
In this paper, we investigate ways to mitigate the problem of decoder error propagation (DEP) in sliding window decoding (SWD) of protograph-based spatially coupled low-density parity-check (SC-LDPC) codes for large frame length or streaming applications. In particular, in order to avoid subdividing a long frame into a series of shorter frames by using termination to combat DEP, we consider alteri
We introduce lower-bound certificates for classical planning tasks, which can be used to prove the unsolvability of a task or the optimality of a plan in a way that can be verified by an independent third party. We describe a general framework for generating lower-bound certificates based on pseudo-Boolean constraints, which is agnostic to the planning algorithm used. As a case study, we show how
