Real-time edge-enhanced optical correlator

The performance of five symbol lock detectors are compared. They are the square-law detector with overlapping (SQOD) and non-overlapping (SQNOD) integrators, the absolute value detectors with overlapping and non-overlapping (AVNOD) integrators and the signal power estimator detector (SPED). The analysis considers various scenarios when the observation interval is much larger or equal to the symbol synchronizer loop bandwidth, which has not been considered in previous analyses. Also, the case of threshold setting in the absence of signal is considered. It is shown that the SQOD outperforms all others when the threshold is set in the presence of signal, independent of the relationship between loop bandwidth and observation period. On the other hand, the SPED outperforms all others when the threshold is set in the presence of noise only

Symbol lock detection implemented with nonoverlapping integration intervals

A symbol lock detector is introduced for an incoming coherent digital communication signal which utilizes a subcarrier modulated with binary symbol data, d(sub k), and known symbol interval T by integrating binary values of the signal over nonoverlapping first and second intervals selected to be T/2, delaying the first integral an interval T/2, and either summing or multiplying the second integral with the first one that preceded it to form a value X(sub k). That value is then averaged over a number M of symbol intervals to produce a static value Y. A symbol lock decision can then be made when the static value Y exceeds a threshold level delta

Wide Tuning Capability for Spacecraft Transponders

A document presents additional information on the means of implementing a capability for wide tuning of microwave receiver and transmitter frequencies in the development reported in the immediately preceding article, VCO PLL Frequency Synthesizers for Spacecraft Transponders (NPO- 42909). The reference frequency for a PLL-based frequency synthesizer is derived from a numerically controlled oscillator (NCO) implemented in digital logic, such that almost any reference frequency can be derived from a fixed crystal reference oscillator with microhertz precision. The frequency of the NCO is adjusted to track the received signal, then used to create another NCO frequency used to synthesize the transmitted signal coherent with, and at a specified frequency ratio to, the received signal. The frequencies can be changed, even during operation, through suitable digital programming. The NCOs and the related tracking loops and coherent turnaround logic are implemented in a field-programmable gate array (FPGA). The interface between the analog microwave receiver and transmitter circuits and the FPGA includes analog-to-digital and digital-toanalog converters, the sampling rates of which are chosen to minimize spurious signals and otherwise optimize performance. Several mixers and filters are used to properly route various signals

Nelumbo Nucifera (Lotus): A Review on Ethanobotany, Phytochemistry and Pharmacology

Nelumbo nucifera Gaertn (Nymphaeaceae), a perennial aquatic plant, has been used as a medicinal herb in China and India. It has been recorded in the most famous medicinal book in China for more than 400 years. Different part of plant (leaves, seeds, flower, and rhizome) can be used in traditional system of medicine. In traditional system of medicine, the different parts of plant is reported to possess beneficial effects as in for the treatment of pharyngopathy, pectoralgia, spermatorrhoea, leucoderma, smallpox, dysentery, cough, haematemesis, epistaxis, haemoptysis, haematuria, metrorrhagia, hyperlipidaemia, fever, cholera, hepatopathy and hyperdipsia. Following the traditional claims for the use of N.nucifera as cure of numerous diseases considerable efforts have been made by researchers to verify it’s utility through scientific pharmacological screenings. The pharmacological studies have shown that N.nucifera posseses various notable pharmacological activities like amti-ischemic, antioxidant, anticancer, antiviral, antiobesity, lipolytic, hypocholestemic, antipyretic, hepatoprotective, hypoglycaemic, antidiarrhoeal, antifungal, antibacterial, antiinflammatory and diuretic activities. A wide variety of phytoprinciples have been isolated from the plant. The present review is an effort to consolidate traditional, ethnobotanic, phytochemical and pharmacological information available on N.nucifera

Fat Necrosis of the Breast: A Pictorial Review of the Mammographic, Ultrasound, CT, and MRI Findings with Histopathologic Correlation

Fat necrosis of the breast is a challenging diagnosis due to the various appearances on mammography, ultrasound, CT, PET-CT, and MRI. Although mammography is more specific, ultrasound is a very important tool in making the diagnosis of fat necrosis. MRI has a wide spectrum of findings for fat necrosis and the appearance is the result of the amount of the inflammatory reaction, the amount of liquefied fat, and the degree of fibrosis. While CT and PET-CT are not first line imaging examinations for the diagnosis of breast cancer or fat necrosis, they are frequently performed in the surveillance and staging of disease. Knowledge of how fat necrosis presents on these additional imaging techniques is important to prevent misinterpretation of the imaging findings. Gross and microscopic appearances of fat necrosis depend on the age of the lesion; the histologic examination of fat necrosis is usually straightforward. Knowledge of the variable appearances of fat necrosis on a vast array of imaging modalities will enhance a radiologist's accuracy in the analysis and interpretation of fat necrosis versus other diagnoses

Generating Ka-Band Signals Using an X-Band Vector Modulator

A breadboard version of a transmitter for radio communication at a carrier frequency of 32 GHz (which is in the Ka band) utilizes a vector modulator operating at a carrier frequency of 8 GHz (the low end of the X band) to generate any of a number of advanced modulations that could include amplitude and/or phase modulation components. The 8-GHz modulated signal is mixed with a 24-GHz signal generated by an upconverter to obtain the desired 32-GHz modulated output. The transmitter is being developed as a prototype of downlink transmitters for transmission of data from spacecraft to Earth at high rates (>100 Mb/s). The transmitter design could also be adapted to terrestrial and Earth/satellite communication links. The advanced modulations (which can include M-ary phase-shift keying (M-PSK), offset phase-shift keying (OPSK), and M-ary quadrature amplitude modulation (M-QAM). These modulations are needed because for a given amount of signal bandwidth, they enable transmission of data at rates greater than those of older, simpler modulation schemes. The transmitter architecture (see figure) was chosen not only to enable generation of the required modulations at 32 GHz but also to reduce the number of components needed to implement the transmitter. Instead of incorporating an 8-GHz signal source, the transmitter utilizes an 8-GHz signal generated by a voltage-controlled oscillator that is part of an X-band transponder with which the fully developed version of this transmitter would be used in the original intended spacecraft application. The oscillator power is divided onto two paths, one of which goes through the vector modulator, the other through amplifiers and a 3 frequency multiplier. Band-pass filters are included downstream of the frequency multiplier to suppress unwanted harmonics

High-Throughput, Adaptive FFT Architecture for FPGA-Based Spaceborne Data Processors

Exponential growth in microelectronics technology such as field-programmable gate arrays (FPGAs) has enabled high-performance spaceborne instruments with increasing onboard data processing capabilities. As a commonly used digital signal processing (DSP) building block, fast Fourier transform (FFT) has been of great interest in onboard data processing applications, which needs to strike a reasonable balance between high-performance (throughput, block size, etc.) and low resource usage (power, silicon footprint, etc.). It is also desirable to be designed so that a single design can be reused and adapted into instruments with different requirements. The Multi-Pass Wide Kernel FFT (MPWK-FFT) architecture was developed, in which the high-throughput benefits of the parallel FFT structure and the low resource usage of Singleton s single butterfly method is exploited. The result is a wide-kernel, multipass, adaptive FFT architecture. The 32K-point MPWK-FFT architecture includes 32 radix-2 butterflies, 64 FIFOs to store the real inputs, 64 FIFOs to store the imaginary inputs, complex twiddle factor storage, and FIFO logic to route the outputs to the correct FIFO. The inputs are stored in sequential fashion into the FIFOs, and the outputs of each butterfly are sequentially written first into the even FIFO, then the odd FIFO. Because of the order of the outputs written into the FIFOs, the depth of the even FIFOs, which are 768 each, are 1.5 times larger than the odd FIFOs, which are 512 each. The total memory needed for data storage, assuming that each sample is 36 bits, is 2.95 Mbits. The twiddle factors are stored in internal ROM inside the FPGA for fast access time. The total memory size to store the twiddle factors is 589.9Kbits. This FFT structure combines the benefits of high throughput from the parallel FFT kernels and low resource usage from the multi-pass FFT kernels with desired adaptability. Space instrument missions that need onboard FFT capabilities such as the proposed DESDynl, SWOT (Surface Water Ocean Topography), and Europa sounding radar missions would greatly benefit from this technology with significant reductions in non-recurring cost and risk

Ductal Carcinoma in Situ of the Breast: MR Imaging Findings With Histopathologic Correlation.

Ductal carcinoma in situ (DCIS) is a noninvasive malignancy that is commonly encountered at routine breast imaging. It may be a primary tumor or may be seen in association with other focal higher-grade tumors. Early detection is important because of the large proportion of DCIS that can progress to invasive carcinoma. The extent of DCIS involvement is frequently underestimated at mammography, which can reliably help detect only calcified DCIS; consequently, magnetic resonance (MR) imaging evaluation can alter the course of treatment. Seven biopsy-proved cases of DCIS were evaluated with T2-weighted MR imaging sequences, as well as T1-weighted sequences performed both before and after contrast material administration. The signal intensity and enhancement patterns of the tumors were analyzed, and the findings were correlated with the relevant underlying histopathologic features. Common enhancement patterns of DCIS include clumped linear-ductal enhancement, clumped focal enhancement, and masslike enhancement. The most common enhancement distribution pattern is segmental, followed by focal, diffuse, linear-ductal, and regional patterns. At T2-weighted MR imaging, DCIS is typically isointense relative to breast parenchyma; less commonly, it is hypointense or hyperintense. The use of MR imaging in the evaluation of DCIS is controversial, and many questions remain with regard to treatment and management. However, breast MR imaging can be extremely useful in the preoperative diagnosis and evaluation of DCIS when used in conjunction with other imaging modalities

Nelumbo Nucifera (Lotus): A Review on Ethanobotany, Phytochemistry and Pharmacology

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A Hybrid Approach for Data Warehouse View Selection ABSTRACT

Materialized view selection is one of the crucial decisions in designing a data warehouse for optimal efficiency. Static selection of views may materialize certain views that are not beneficial as the data and usage trends change overtime. On the contrary, dynamic selection of views works better only for queries demanding a high degree of aggregation. These facts point to the need for a technique that combines the improved response time of the static approach and the automated tuning capability of the dynamic approach. In this paper, we propose a hybrid approach for the selection of materialized views. The idea is to partition the collection of all views into a static and a dynamic set such that views selected for materialization from the static set are persistent over multiple query (and maintenance) windows, whereas views selected from the dynamic set can be queried and/or replaced on the fly. Highly aggregated views are selected on the fly based on the query access patterns of users, whereas the more detailed static set of views play a significant role in the efficient maintenance of the dynamic set of views and in answering certain detailed view queries. We prove that our proposed strategy satisfies the monotonicity requirements, which is essential for the greedy heuristic to deliver competitive solutions. 1 Experimental results show that our approach outperforms Dynamat; a well-known dynamic view management system that is known to outperform optimal static view selection