Towards Performance Portable Graph Algorithms

In today's data-driven world, our computational resources have become heterogeneous, making the processing of large-scale graphs in an architecture agnostic manner crucial. Traditionally, hand-optimized high-performance computing (HPC) solutions have been studied and used to implement highly efficient and scalable graph algorithms. In recent years, several graph processing and management systems have also been proposed. Hand optimized HPC approaches require high levels of expertise and graph processing frameworks suffer from expressibility and performance. Portability is a major concern for both approaches. The main thesis of this work is that block-based graph algorithms offer a compromise between efficient parallelism and architecture agnostic algorithm design for a wide class of graph problems. This dissertation seeks to prove this thesis by focusing the work on the three pillars; data/computation partitioning, block-based algorithm design, and performance portability. In this dissertation, we first show how we can partition the computation and the data to design efficient block-based algorithms for solving graph merging and triangle counting problems. Then, generalizing from our experiences, we propose an algorithmic framework, for shared-memory, heterogeneous machines for implementing block-based graph algorithms; PGAbB. PGAbB aims to maximally leverage different architectures by implementing a task-based execution on top of a block-based programming model. In this talk we will discuss PGAbB's programming model, algorithmic optimizations for scheduling, and load-balancing strategies for graph problems on real-world and synthetic inputs.Ph.D

Active positive sloped equalizer for x-band SiGe BiCMOS phased array applications

This work presents an active equalizer circuit with positive gain slope at X-Band (8 - 12 GHz). Compared to passive examples, the active equalizer realized better filter and impedance characteristics in frequency of interest with increased functionality for a single amplification stage. It achieved close to 10 dB of peak gain, a + 1.13 dB/GHz gain slope with 2.8 dB NF by utilizing cascode topology. The design reaches a -1.5 dBm input-referred compression point (input-P1dB) while consuming 46 mW of power. To the best of authors’ knowledge, the presented work achieves the best on-chip gain, a gain slope and NF performance in the literature as an equalizer that utilizes SiGe BiCMOS technology

A SiGe BiCMOS bypass low-noise amplifier for x-band phased array RADARs

This paper presents a bypass low noise amplifier (LNA) for X-band phased array applications in 0.25μm SiGe BiCMOS technology. The trade-off between gain and bypass modes is considered to achieve high gain as well as low noise figure for gain mode while maintaining reasonable insertion loss with high power handling capability in bypass mode. In gain mode, the LNA achieves a measured gain of 17-14.2 dB and a noise figure of 1.75-1.95 dB over the 8-12 GHz band while consuming 27.4mW of DC-power. The measured input-referred I-dB compression point (IP 1dB ) is -3.9 dBm at 10 GHz. When operating in bypass mode, the measured insertion loss is 6.5-5.95 dB over the entire X-band with the measured IP 1dB of 15.1 dBm at 10 GHz, and it dissipates only 1μW power. Thanks to the bypassing technique, an increase of about 19 dB is achieved for IP 1dB in bypass mode compare to the gain mode. The measured return losses are better than 10 dB for both operating modes over whole X-band. The effective chip area excluding the pads is 0.3 mm 2

Effects of Brand on Consumer Preferences: A study in Turkmenistan

Using a measurement model of brand name and consumer preferences, this study aims to investigate the effects of brand name on consumer preferences in Turkmenistan. This study sought to investigate specifically, the influence of brand name on consumer’s preferences by utilizing structural equation modeling (SEM) technique. Moreover, all possible correlations between these dimensions or domains of brand name and consumer preferences are also empirically tested. In the context of the study, the introduced model was tested by a questionnaire instrument with 10 items excluding the demographic variables. A total of 422 completed copies of questionnaires were evaluated for analysis. The results suggest that, brand name variable have statistically significant relationships with consumer preferences variable. The findings of the study indicated positive correlations among the two variables with high factor loadings. Brand name of a product has significant impact on the overall preferences of the consumer

A k-band 5G phased array RX channel with 3.3-dB NF and 28.5-dB gain in 130-nm SiGe

This paper presents a low-noise K-band phased array receive channel implemented in a 130-nm SiGe BiCMOS process. The IC consists of a cascode LNA, a vector modulator phase shifter (PS), and a current-steering VGA. The LNA employs a shunt inductor at the intermediate node of the cascode for noise reduction purposes. The PS generates I/Q signals by lumped quadrature hybrids for low noise operation. Various process compensation capabilities are employed within the PS to reliably achieve high resolution. The measured results demonstrated a peak gain of 28.5 dB at 24 GHz with a 3-dB bandwidth of 22-27 GHz. The measured noise figure is 3.3 dB, which is better than state-of-the-art among Si-based phased-array channels. For 6-b phase control, the rms phase error is 4∘ and 0.2∘ without and with calibration, respectively; the rms gain error being 1 dB for both cases. For 4-b gain control with 0.4-dB/step, the rms amplitude/phase errors are 0.1-dB/0.5∘. Across different phase settings, the IC has an OP1dB of -2 to -3 dBm, with a power consumption of 48 mW. The total chip area is 1.33 mm2, excluding the pads

Effects of Land-Use Change on the Soil Organic Carbon and Selected Soil Properties in the Sultan Marshes, Turkey

This study aims to assess the effects of land-use changes on the carbon storage capacity and some soil properties of The Sultan Marshes, a wetland partially drained and converted to other land uses during the middle of the last century. Undisturbed soil sampling was performed in different land-use types (rangelands, shrubs, marsh, agriculture, and dried lake area) in the wetland area at depths of 0-50 cm, and soil organic carbon (SOC), bulk density, and carbon stocks of soils for each land use type were calculated at 10 cm soil depth levels. Furthermore, disturbed soil samples were taken at two soil depths (0-20 cm and 20-40 cm), and the particle size distribution, pH, electrical conductivity (EC), aggregate stability and dispersion ratio (DR) properties of the soils were analyzed. Data were processed using ANOVA, Duncan's test, and Pearson's correlation analysis. The soil properties affected by the land-use change were SOC, carbon stock, pH, EC, aggregate stability, clay, silt, sand contents, and bulk density. SOC and carbon stocks were high in rangeland, marsh, and shrub land, while low in agriculture and drained lake areas. As the soil depth increased, SOC and carbon stock decreased. The organic carbon content of the soils exhibited positive relationships with aggregate stability, clay, and carbon stock, while it showed a negative correlation with bulk density, pH, and DR. The results showed that s drainage and conversion of the wetland caused a significant decrease in the carbon contents of the soils

A 26-GHz vector modulator in 130-nm SiGe BiCMOS achieving monotonic 10-b phase resolution without calibration

This paper presents a high-resolution (10-b) vevtor-modulator (VM) phase shifter (PS) in 130-nm SiGe BiCMOS targeting 5G applications at 26 GHz. It employs a Gilbert-cell RF core, the tail current of which is controlled by an 8-b low-power current-steering DAC and 2-b I/Q sign switches. The DAC includes an on-chip PTAT current reference with process compensation capabilities. A 2-stage RC polyphase filter (PPF) is used to generate the quadrature signals. Without any calibration or correction of PS control signals, the measured results demonstrate completely monotonic 2(10) phase states, covering the full 0-360 degrees range without any dead zones or overlapping phase states. The worst case (maximum) phase difference between any adjacent states is 0.65 degrees. The VM exhibits an average insertion loss of 0.5 dB at 26 GHz with a 3-dB BW of 8 GHz, an rms amplitude error of 0.2 dB, IP1dB of 2 dBm, and 23 mW dc power dissipation. Potential applications are in RF beamforming and RF self-interference cancellation

Performance Evaluation of VANET Routing Protocols in Madinah City

Traffic management challenges in peak seasons for popular destinations such as Madinah city have accelerated the need for and introduction of autonomous vehicles and Vehicular ad hoc networks (VANETs) to assist in communication and alleviation of traffic congestions. The primary goal of this study is to evaluate the performance of communication routing protocols in VANETs between autonomous and human-driven vehicles in Madinah city in varying traffic conditions. A simulation of assorted traffic distributions and densities were modeled in an extracted map of Madinah city and then tested in two application scenarios with three ad hoc routing protocols using a combination of traffic and network simulation tools working in tandem. The results measured for the average trip time show that opting for a fully autonomous vehicle scenario reduces the trip time of vehicles by approximately 7.1% in high traffic densities and that the reactive ad hoc routing protocols induce the least delay for network packets to reach neighboring VANET vehicles. From these observations, it can be asserted that autonomous vehicles provide a significant reduction in travel time and that either of the two reactive ad hoc routing protocols could be implemented for the VANET implementation in Madinah city. Furthermore, we perform an ANOVA test to examine the effects of the factors that are considered in our study on the variation of the results

Unusual Combination of Tracheobronchopathia Osteochondroplastica and AA Amyloidosis

Tracheobronchopathia osteochondroplastica (TO) is a rare disorder of unknown cause characterized by the presence of multiple submucosal osseous and/or cartilaginous nodules that protrude into the lumen of the trachea and large bronchi. A simultaneous diagnosis of TO and amyloidosis is rarely reported. In this report, a case initially suspected to be asthma bronchiole that could not be treated, was radiologically diagnosed as TO, and also secondary amyloidosis is presented. A 53 years, man patient reported a 3 years history of dyspnea. Pulmonary function tests (PFTs) showed an obstructive pattern. Chest X-rays revealed right middle lobe atelectasis. FOB and CT detected nodular lesions in the trachea and in the anterior and lateral walls of the main bronchi. AA amyloidosis was confirmed by endobronchial biopsy. In the abdominal fat pad biopsy, amyloidosis was not detected. Asthma bronchiole was excluded by PFTs. This case illustrates that it is possible for TO and amyloidosis to masquerade as asthma. TO and amyloidosis should be suspected in patients of older ages with asthma and especially with poorly treated asthmatic patients. Although nodular lesions in the anterior and lateral tracheobronchial walls are typical for TO, a biopsy should be obtained to exclude amyloidosis