Designing a Hadoop system based on computational resources and network delay for wide area networks

This paper proposes a Hadoop system that considers both slave server’s processing capacity and network delay for wide area networks to reduce the job processing time. The task allocation scheme in the proposed Hadoop system divides each individual job into multiple tasks using suitable splitting ratios and then allocates the tasks to different slaves according to the computational capability of each server and the availability of network resources. We incorporate software-defined networking to the proposed Hadoop system to manage path computation elements and network resources. The performance of proposed Hadoop system is experimentally evaluated with fourteen machines located in the different parts of the globe using a scale-out approach. A scale-out experiment using the proposed and conventional Hadoop systems is conducted by executing both single job and multiple jobs. The practical testbed and simulation results indicate that the proposed Hadoop system is effective compared to the conventional Hadoop system in terms of processing time

Proactive Received Power Prediction Using Machine Learning and Depth Images for mmWave Networks

This study demonstrates the feasibility of the proactive received power prediction by leveraging spatiotemporal visual sensing information toward the reliable millimeter-wave (mmWave) networks. Since the received power on a mmWave link can attenuate aperiodically due to a human blockage, the long-term series of the future received power cannot be predicted by analyzing the received signals before the blockage occurs. We propose a novel mechanism that predicts a time series of the received power from the next moment to even several hundred milliseconds ahead. The key idea is to leverage the camera imagery and machine learning (ML). The time-sequential images can involve the spatial geometry and the mobility of obstacles representing the mmWave signal propagation. ML is used to build the prediction model from the dataset of sequential images labeled with the received power in several hundred milliseconds ahead of when each image is obtained. The simulation and experimental evaluations using IEEE 802.11ad devices and a depth camera show that the proposed mechanism employing convolutional LSTM predicted a time series of the received power in up to 500 ms ahead at an inference time of less than 3 ms with a root-mean-square error of 3.5 dB

Virgin coconut oil prepared by protease-assisted process : Characteristics and application

Doctor of Philosophy (Food Science and Technology), 2018Coconut milk and meat at three different maturity stages including immature coconut (IMC), mature coconut (MC) and overlay mature coconut (OMC) had varying proximate compositions. Compositions of coconut milk generally were in accordance with those found in coconut meat. Cocosin with molecular weight of 55 kDa was observed as the major protein in all coconut milks but its band intensity slightly decreased with increasing maturity stages. Oil droplet size increased as maturity stages increased. Nevertheless, virgin coconut oil (VCO) extracted from coconut with three different maturity stages had no impact on fatty acid composition and physicochemical properties. VCO separated using Alcalase showed the highest recovery (95.64%) when coconut milk from OMC was used as starting material. All VCO samples had waterlike appearance and contained medium chain fatty acid (MCFA), especially lauric acid as a major fatty acid, (49.74-51.18 g/100g). Myristic acid in the range of 18.70-19.84 g/100g was present in all VCO. All VCO samples had low lipid hydrolysis and oxidation, indicating that maturity stages had no influence on oil stability. Albumin and globulin were the predominant protein fractions in defatted coconut meat. Both fractions showed the differences in protein patterns and amino acid compositions. Varying emulsifying property was obtained between both fractions. Albumin, water-soluble protein fraction, exhibited lower emulsifying properties, compared to globulin (salt-soluble) counterpart. However, globulin fraction was more susceptible to hydrolysis by Alcalase, leading to the higher collapse of emulsion of coconut milk after being hydrolyzed. This contributed to the higher oil recovery from coconut milk. Difference was observed in degree of hydrolysis (DH), oil recovery, microstructure and protein pattern of coconut milk hydrolyzed by partially purified protease from seabass pyloric caeca (PPSP) and commercial trypsin (CT) at different proteolytic levels (5 and 10 units/g protein) at 60 °C for various hydrolysis times (0-150 min). The highest VCO yield (77.35%) was found when sample was hydrolyzed by PPSP (10 units/g protein) for 150 min. Based on DH and electrophoretic study, proteins in coconut milk were more prone to hydrolysis by PPSP, compared to CT. Therefore, PPSP could be used as an alternative processing aid and the efficiency was higher than CT. PPSP was further used in combination with different treatments including microfluidization, chill-thawing and freeze-thawing for extraction of VCO. Coconut milk hydrolyzed by PPSP at 10 units/g protein, followed by freeze-thawing showed the highest yield among other samples (p<0.05). Conversely, the lowest VCO yield was attained for coconut milk homogenized at 4000 psi, followed by hydrolysis using PPSP (5 units/ g protein). Hydrolysis by PPSP, followed by freeze-thawing of 5 cycle rendered the highest yield of VCO (98.6%). However, no marked difference was observed in fatty acid profile, moisture content, free fatty acid content (FFA) and oxidative stability among all VCO extracted from aforementioned methods. Because of high stability and various health benefits, VCO in combination with fish oil (FO) rich in n-3 fatty acids at different ratios (95:5, 90:10, 85:15, v/v) was used to prepare a functional mayonnaise. Chemical and physical changes were monitored during the storage of 30 days at room temperature (30-32 °C) in comparison with those of mayonnaise prepared using soybean oil (SO). Addition of FO up to 10% in VCO/FO blend could yield the mayonnaise with sensorial acceptability. Oxidative stability varied with mayonnaises containing different oils. Mayonnaise sample with VCO was less prone to lipid oxidation throughout storage of 30 days. Types of oil used for preparation of mayonnaise and storage time affected the color, textural and rheological properties of resulting mayonnaise. In general, mayonnaise containing VCO/FO (90:10) blend showed the property equivalent to that prepared using SO. Thus, VCO could be incorporated in combination with FO at appropriate level to prepare a functional mayonnaise with acceptability and oxidative stability. Therefore, VCO could be successfully produced with the aid of fish trypsin in conjunction with repeated freeze-thawing cycles. The resulting VCO could be employed as food ingredient or other applications

SEDIQA: Sound Emitting Document Image Quality Assessment in a Reading Aid for the Visually Impaired

For visually impaired people (VIPs), the ability to convert text to sound can mean a new level of independence or the simple joy of a good book. With significant advances in optical character recognition (OCR) in recent years, a number of reading aids are appearing on the market. These reading aids convert images captured by a camera to text which can then be read aloud. However, all of these reading aids suffer from a key issue—the user must be able to visually target the text and capture an image of sufficient quality for the OCR algorithm to function—no small task for VIPs. In this work, a sound-emitting document image quality assessment metric (SEDIQA) is proposed which allows the user to hear the quality of the text image and automatically captures the best image for OCR accuracy. This work also includes testing of OCR performance against image degradations, to identify the most significant contributors to accuracy reduction. The proposed no-reference image quality assessor (NR-IQA) is validated alongside established NR-IQAs and this work includes insights into the performance of these NR-IQAs on document images. SEDIQA is found to consistently select the best image for OCR accuracy. The full system includes a document image enhancement technique which introduces improvements in OCR accuracy with an average increase of 22% and a maximum increase of 68%

Capacity Enhancement in 60 GHz Based D2D Networks by Relay Selection and Scheduling

Millimeter-wave or 60 GHz communication is a promising technology that enables data rates in multigigabits. However, its tremendous propagation loss and signal blockage may severely affect the network throughput. In current data-centric device-to-device (D2D) communication networks, the devices with intended data communications usually lay in close proximity, unlike the case in voice-centric networks. So the network can be visualized as a naturally formed groups of devices. In this paper, we jointly consider resource scheduling and relay selection to improve network capacity in 60 GHz based D2D networks. Two types of transmission scenarios are considered in wireless personal area networks (WPANs), intra and intergroup. A distributed receiver based relay selection scheme is proposed for intragroup transmission, while a distance based relay selection scheme is proposed for intergroup transmission. The outage analysis of our proposed relay selection scheme is provided along with the numerical results. We then propose a concurrent transmission scheduling algorithm based on vertex coloring technique. The proposed scheduling algorithm employs time and space division in mmWave WPANs. Using vertex multicoloring, we allow transmitter-receiver (Tx-Rx) communication pairs to span over more colors, enabling better time slot utilization. We evaluate our scheduling algorithm in single-hop and multihop scenarios and discover that it outperforms other schemes by significantly improving network throughput

Areion: Highly-Efficient Permutations and Its Applications (Extended Version)

In real-world applications, the overwhelming majority of cases require (authenticated) encryption or hashing with relatively short input, say up to 2K bytes. Almost all TCP/IP packets are 40 to 1.5K bytes, and the maximum packet lengths of major protocols, e.g., Zigbee, Bluetooth low energy, and Controller Area Network (CAN), are less than 128 bytes. However, existing schemes are not well optimized for short input. To bridge the gap between real-world needs (in the future) and limited performances of state-of-the-art hash functions and authenticated encryptions with associated data (AEADs) for short input, we design a family of wide-block permutations Areion that fully leverages the power of AES instructions, which are widely deployed in many devices. As for its applications, we propose several hash functions and AEADs. Areion significantly outperforms existing schemes for short input and even competitive to relatively long messages. Indeed, our hash function is surprisingly fast, and its performance is less than three cycles/byte in the latest Intel architecture for any message size. It is significantly much faster than existing state-of-the-art schemes for short messages up to around 100 bytes, which are the most widely-used input size in real-world applications, on both the latest CPU architectures (IceLake, Tiger Lake, and Alder Lake) and mobile platforms (Pixel 7, iPhone 14, and iPad Pro with Apple M2)

High efficiency and high frequency resonant tunneling diode sources

Terahertz (THz) technology has been generating a lot of interest due to the numerous potential applications for systems working in this previously unexplored frequency range. THz radiation has unique properties suited for high capacity communication systems and non-invasive, non-ionizing properties that when coupled with a fairly good spatial resolution are unparalleled in its sensing capabilities for use in biomedical, industrial and security fields. However, in order to achieve this potential, effective and efficient ways of generating THz radiation are required. Devices which exhibit negative differential resistance (NDR) in their current-voltage (I – V) characteristics can be used for the generation of these radio frequency (RF) signals. Among them, the resonant tunnelling diode (RTD) is considered to be one of the most promising solid-state sources for millimeter and submillimeter wave radiation, which can operate at room temperature. However, the main limitations of RTD oscillators are producing high output power and increasing the DC-to-RF conversion efficiency. Although oscillation frequencies of up to 1.98 THz have been already reported, the output power is in the range of micro-Watts and conversion efficiencies are under 1 %. This thesis describes the systematic work done on the design, fabrication, and characterization of RTD-based oscillators in monolithic microwave/millimeter-wave integrated circuits (MMIC) that can produce high output power and have a high conversion efficiency at the same time. At the device level, parasitic oscillations caused by the biasing line inductance when the diode is biased in the NDR region prevents accurate characterization and compromises the maximum RF power output. In order to stabilise the NDR devices, a common method is the use of a suitable resistor connected across the device, to make the differential resistance in the NDR region positive. However, this approach severely hinders the diode’s performance in terms of DC-to-RF conversion efficiency. In this work, a new DC bias decoupling circuit topology has been developed to enable accurate, direct measurements of the device’s NDR characteristic and when implemented in an oscillator design provides over a 10-fold improvement in DC-to-RF conversion efficiency. The proposed method can be adapted for higher frequency and higher power devices and could have a major impact with regards to the adoption of RTD technology, especially for portable devices where power consumption must be taken into consideration. RF and DC characterization of the device were used in the realization on an accurate large-signal model of the RTD. S-parameter measurements were used to determine an accurate small-signal model for the device’s capacitance and inductance, while the extracted DC characteristics where used to replicate the I-V characteristics. The model is able to replicate the non-stable behavior of RTD devices when biased in the NDR region and the RF characteristics seen in oscillator circuits. It is expected that the developed model will serve in future optimization processes of RTD devices in millimeter and submillimeter wave applications. Finally, a wireless data transmission link operating in the Ka-band (26.5 GHz – – 40 GHz) using two RTDs operating as a transmitter and receiver is presented in this thesis. Wireless error-free data transfer of up to 2 gigabits per second (Gbit/s) was achieved at a transmission distance of 15 cm. In summary, this work makes important contributions to the accurate characterization, and modeling of RTDs and demonstrates the feasibility of this technology for use in future portable wireless communication systems and imaging setups

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Cooperative Vehicular Platooning (Co-VP) is a paradigmatic example of a Cooperative Cyber-Physical System (Co-CPS), which holds the potential to vastly improve road safety by partially removing humans from the driving task. However, the challenges are substantial, as the domain involves several topics, such as control theory, communications, vehicle dynamics, security, and traffic engineering, that must be coupled to describe, develop and validate these systems of systems accurately. This work presents a comprehensive survey of significant and recent advances in Co-VP relevant fields. We start by overviewing the work on control strategies and underlying communication infrastructures, focusing on their interplay. We also address a fundamental concern by presenting a cyber-security overview regarding these systems. Furthermore, we present and compare the primary initiatives to test and validate those systems, including simulation tools, hardware-in-the-loop setups, and vehicular testbeds. Finally, we highlight a few open challenges in the Co-VP domain. This work aims to provide a fundamental overview of highly relevant works on Co-VP topics, particularly by exposing their inter-dependencies, facilitating a guide that will support further developments in this challenging field.info:eu-repo/semantics/publishedVersio