Distributed microprocessors in a tactical universal modem

The distributed microprocessor system associated with a wideband signal conversion unit (WBSCU) is described. Multiple embedded 8086 and 2901 microprocessors, supported by dedicated hardware modules, perform the required real time operations for both transmit and receive functions. Commands from a host computer determine the configuration of the WBSCU via the IEEE 488 bus. Each of the four WBSCU channels is assigned to process a specified IF waveform; each channel configures its own resources and, in some cases, borrows resources from other channels. The processed waveform data is communicated from individual channels to redundant global memories. Data flow between the user community and global memories occurs via redundant 1553 buses through intelligent Bus Interface Units. Each WBSCU channel contains one 2901 bit slice machine and one 8086 microprocessor. The 2901 provides high speed processing capability for the most time critical operations. The 8086 is used for lower speed processing tasks where its high level language capability can be better exploited. Each 8086 has a global bus for wideband interprocessor communication, and a local bus for 8086/2901, master/slave communication. Software architecture consists of a control and communications structure governing mode dependent signal processing tasks

Application of Consensus Scoring and Principal Component Analysis for Virtual Screening against β-Secretase (BACE-1)

BACKGROUND: In order to identify novel chemical classes of β-secretase (BACE-1) inhibitors, an alternative scoring protocol, Principal Component Analysis (PCA), was proposed to summarize most of the information from the original scoring functions and re-rank the results from the virtual screening against BACE-1. METHOD: Given a training set (50 BACE-1 inhibitors and 9950 inactive diverse compounds), three rank-based virtual screening methods, individual scoring, conventional consensus scoring and PCA, were judged by the hit number in the top 1% of the ranked list. The docking poses were generated by Surflex, five scoring functions (Surflex_Score, D_Score, G_Score, ChemScore, and PMF_Score) were used for pose extraction. For each pose group, twelve scoring functions (Surflex_Score, D_Score, G_Score, ChemScore, PMF_Score, LigScore1, LigScore2, PLP1, PLP2, jain, Ludi_1, and Ludi_2) were used for the pose rank. For a test set, 113,228 chemical compounds (Sigma-Aldrich® corporate chemical directory) were docked by Surflex, then ranked by the same three ranking methods motioned above to select the potential active compounds for experimental test. RESULTS: For the training set, the PCA approach yielded consistently superior rankings compared to conventional consensus scoring and single scoring. For the test set, the top 20 compounds according to conventional consensus scoring were experimentally tested, no inhibitor was found. Then, we relied on PCA scoring protocol to test another different top 20 compounds and two low micromolar inhibitors (S450588 and 276065) were emerged through the BACE-1 fluorescence resonance energy transfer (FRET) assay. CONCLUSION: The PCA method extends the conventional consensus scoring in a quantitative statistical manner and would appear to have considerable potential for chemical screening applications

Symulacja otworowa metodą Frac-Pack

During the hydrocarbon production, the formation sand movement has a frequent negative influx to the process because of its hazardous nature. Gravel pack placement is a common well treatment procedure for prevention of formation sand flow to the wellbore. This method is used in petroleum engineering industrial practice since 1950s. Based on it as a conventional technique Frac-Pack method came up as a new modern technology of sand control containing gravel pack placement and hydraulic fracturing all-in-one procedure. In Frac-Pack application, the appropriate viscosified fluid and proppant selection has a key role for achievement of desired fracture height, length and width. Fracture dimensions are controlled by TSO (Tip-Screenout) fracturing procedure. In this paper basic types of proppant are presented as well as resin coated sand, which improves packing of fracture with proppant. Numerous and various Frac-Pack fluids able to resist the high temperature and pressure are described. Downhole Frac-Pack equipment is also presented. Paper also contains a field example of Frac-Pack application performed on one of the Adriatic offshore gas fields, Republic of Croatia.W trakcie wydobywania węglowodorów mamy często do czynienia z negatywnym i niebezpiecznym zjawiskiem przemieszczania się piasku. Zastosowanie pakera żwirowego stanowi podstawowy sposób zabezpieczenia przed napływem piasku do otworu. Metodę tę stosuje się w inżynierii naftowej od lat pięćdziesiątych ubiegłego stulecia. Na tej podstawie opracowano tradycyjna technikę Frac-Pack jako nowoczesną metodę kontroli zapiaszczenia za pomocą połączonego zastosowania pakera żwirowego i szczelinowania hydraulicznego. W przypadku Frac-Pack płyny o odpowiedniej lepkości i właściwie dobranych materiałach podsadzkowych odgrywają kluczową rolę w osiągnięciu wymaganej wysokości, długości i szerokości szczeliny. Rozmiary szczelin kontrolowane są metodą szczelinowania TSO (Tip-Screenout). W artykule przedstawiono podstawowe rodzaje podsadzki oraz piasek z powłoką żywicową, które wzmagają działanie podsadzki. Opisano różnorodne płyny Frac-Pack odporne na wysoką temperaturę i ciśnienie. Przedstawiono także wgłębne wyposażenie Frac-Pack. W artykule pokazano przykładowe zastosowanie praktyczne Frac-Pack na jednym z chorwackich złóż gazu ziemnego na Adriatyku

A cross-terms geometry based method for components instantaneous frequency estimation using the Cross Wigner-Ville distribution

A novel method for the signal components instantaneous frequency (IF) estimation based on the CrossWigner-Ville distribution (XWVD) is presented. The cross-terms in the XWVD are deliberately formed between the analyzed signal and a reference signal. The proposed method yields a scaled and time shifted image that closely resembles the instantaneous frequency laws of the components present in the signal. As the interferences location follow geometrical rules, and by using a reference signal well localized in time and frequency, the time-frequency coordinates of the analyzed signal components IF can be calculated by an automatic procedure described below. The performance of the method is tested on both synthetic and real-life signals, showing improvements over another recently proposed components extraction method.Scopu