bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Resource Exhaustion Attacks against Wireless Mobile Devices
Authors: Desnitsky Vasily , Kotenko Igor , Zakoldaev Danil
Published: May 2019

Currently, energy resource exhaustion attacks targeted on modern autonomously working mobile devices are becoming more and more important. The underdevelopment of specialized defenses against energy exhaustion attacks as well as their often hidden nature for the owner of the target device determine a necessity of an integrated approach to modeling and evaluation of this class of attacks and various types of intruders. The paper analyzes conditions of applicability of energy resource exhaustion attacks performed by various classes of intruders, models them on physical implementations of devices for two application areas, and calculates their performance indicators. Application areas are a TCP/IP network of end-user mobile devices and a self-organizing mesh network designed for operational management and emergency response.
Bandwidth and Gain Enhancement of Endfire Radiating Open-Ended Waveguide Using Thin Surface Plasmon Structure
Authors: Kandwal Abhishek , Nie Zedong , Li Jingzhen , Liu Yuhang , WY. Liu Louis , Das Ranjan
Published: May 2019

This paper proposes a technique to enhance the bandwidth and gain of an endfire radiating open-ended waveguide using a thin slow-wave surface plasmon structure. Mounted in the E-plane of the stated waveguide, a thin corrugated slow-wave structure has been used in conjunction with a waveguide transition to generate an endfire electromagnetic beam. An efficient mode conversion from waveguide transition to the corrugate plate resulted in the improved performance of the design. An impedance bandwidth from 8 GHz to 18 GHz has been achieved along with a gain enhancement from 7 dBi to 14.8 dBi using the proposed hybrid design. Endfire radiations have been obtained with a beam width of less than 25° through the proposed hybrid design with an efficiency of about 96 percent.
Design and Development of a Real-Time Optimal Route Recommendation System Using Big Data for Tourists in Jeju Island
Authors: Mehmood Faisal , Ahmad Shabir , Kim DoHyeun
Published: May 2019

Nowadays researchers and engineers are trying to build travel route recommendation systems to guide tourists around the globe. The tourism industry is on the rise and it has attracted researchers to provide such systems for comfortable and convenient traveling. Mobile internet growth is increasing rapidly. Mobile data usage and traffic growth has increased interest in building mobile applications for tourists. This research paper aims to provide design and implementation of a travel route recommendation system based on user preference. Real-time big data is collected from Wi-Fi routers installed at more than 149 unique locations in Jeju Island, South Korea. This dataset includes tourist movement patterns collected from thousands of mobile tourists in the year 2016–2017. Data collection and analysis is necessary for a country to make public policies and development of the global travel and tourism industry. In this research paper we propose an optimal travel route recommendation system by performing statistical analysis of tourist movement patterns. Route recommendation is based on user preferences. User preference can vary over time and differ from one user to another. We have taken three main factors into consideration to the recommend optimal route i.e., time, distance, and popularity of location. Beside these factors, we have also considered weather and traffic condition using a third-party application program interfaces (APIs). We have classified regions into six major categories. Popularity of location can vary from season to season. We used a Naïve Bayes classifier to find the probability of tourists going to visit next location. Third-party APIs are used to find the longitude and latitude of the location. The Haversine formula is used to calculate the distance between unique locations. On the basis of these factors, we recommend the optimal route for tourists. The proposed system is highly responsive to mobile users. The results of this system show that the recommended route is convenient and allows tourists to visit maximum number of famous locations as compared to previous data.
Research on Invulnerability Technology of Node Attack in Space-Based Information Network Based on Complex Network
Authors: Liu Chengxiang , Xiong Wei , Zhang Ying , Sun Yang , Xiong Minghui , Guo Chao
Published: May 2019

With the rapid development of communications technology, the space-based information network (SBIN) is increasingly threatened by the outside world. Dynamic changes in any part of its interior can cause the collapse of the entire network. Therefore, research on the invulnerability of SBIN has become an urgent need to promote the economic development of our country and improve the living standards of our people. To this end, this paper has carried out research on the node-attacked invulnerability of SBIN based on the complex network theory. First, based on the model of SBIN, the internal parameters of the network are analyzed theoretically based on complex networks. Second, the paper proposes an improved tree attack strategy to analyze the invulnerability of SBIN, which constitutes a problem where the traditional attack strategy has a low invulnerability and the connected edge cannot fully realize the network function. Then, based on the improved tree attack strategy algorithm, this paper optimizes the invulnerability of SBIN by constructing four different edge-increasing strategies. Through the research, the LDF edge-increasing strategy makes the entire network flatter and can effectively improve the network’s ability to resist destruction. The research of invulnerability based on the complex network has a certain technical support and theoretical guidance for the construction of a reasonable and stable SBIN.
Noise Reduction for High-Accuracy Automatic Calibration of Resolver Signals via DWT-SVD Based Filter
Authors: Guo Meishan , Wu Zhong
Published: May 2019

High-accuracy calibration of resolver signals is the key to improve its angular measurement accuracy. However, inductive harmonics, residual excitation components, and random noise in signals dramatically restrict the further improvement of calibration accuracy. Aiming to reduce these unexpected noises, a filter based on discrete wavelet transform (DWT) and singular value decomposition (SVD) is designed in this paper. Firstly, the signal was decomposed into a time-frequency domain by DWT and several groups of coefficients were obtained. Next, the SVD operation of a Hankel matrix created from the coefficients was made. Afterwards, the noises were attenuated by reconstructing the signal with a few selected singular values. Compared with a conventional low-pass filter, this method can almost only preserve the fundamental and DC components of the signal because of the multi-resolution characteristic of DWT and the good correspondence between the singular value and frequency. Therefore, the calibration accuracy of the imperfect characteristics could be improved effectively. Simulation and experimental results demonstrated the effectiveness of the proposed method.
Proton Induced Single Event Effect Characterization on a Highly Integrated RF-Transceiver
Authors: Budroweit Jan , Jaksch Mattis Paul , Sznajder Maciej
Published: May 2019

Radio frequency (RF) systems in space applications are usually designed for a single task and its requirements. Flexibility is mostly limited to software-defined adaption of the signal processing in digital signal processors (DSP) or field-programmable gate arrays (FPGA). RF specifications, such as frequency band selection or RF filter bandwidth are thereby restricted to the specific application requirements. New radio frequency integrated circuit (RFIC) devices also allow the software-based reconfiguration of various RF specifications. A transfer of this RFIC technology to space systems would have a massive impact to future radio systems for space applications. The benefit of this RFIC technology allows a selection of different RF radio applications, independent of their RF parameters, to be executed on a single unit and, thus, reduces the size and weight of the whole system. Since most RF application sin space system require a high level of reliability and the RFIC is not designed for the harsh environment in space, a characterization under these special environmental conditions is mandatory. In this paper, we present the single event effect (SEE) characterization of a selected RFIC device under proton irradiation. The RFIC being tested is immune to proton induced single event latch-up and other destructive events and shows a very low response to single failure interrupts. Thus, the device is defined as a good candidate for future, highly integrated radio system in space applications.
Mobile-Phone Antenna Array with Diamond-Ring Slot Elements for 5G Massive MIMO Systems
Authors: Ojaroudi Parchin Naser , Jahanbakhsh Basherlou Haleh , Alibakhshikenari Mohammad , Ojaroudi Parchin Yasser , Al-Yasir Yasir I. A. , Abd-Alhameed Raed A. , Limiti Ernesto
Published: May 2019

A design of mobile-phone antenna array with diamond-ring slot elements is proposed for fifth generation (5G) massive multiple-input/multiple-output (MIMO) systems. The configuration of the design consists of four double-fed diamond-ring slot antenna elements placed at different corners of the mobile-phone printed circuit board (PCB). A low-cost FR-4 dielectric with an overall dimension of 75 × 150 mm2 is used as the design substrate. The antenna elements are fed by 50-Ohm L-shaped microstrip-lines. Due to the orthogonal placement of microstrip feed lines, the diamond-ring slot elements can exhibit the polarization and radiation pattern diversity characteristic. A good impedance bandwidth (S11 ≤ −10 dB) of 3.2–4 GHz has been achieved for each antenna radiator. However, for S11 ≤ −6 dB, this value is 3–4.2 GHz. The proposed design provides the required radiation coverage of 5G smartphones. The performance of the proposed MIMO antenna design is examined using both simulation and experiment. High isolation, high efficiency and sufficient gain-level characteristics have been obtained for the proposed MIMO smartphone antenna. In addition, the calculated total active reflection coefficient (TARC) and envelope correlation coefficient (ECC) of the antenna elements are very low over the whole band of interest which verify the capability of the proposed multi-antenna systems for massive MIMO and diversity applications. Furthermore, the properties of the design in Data-mode/Talk-mode are investigated and presented.
Optimal Home Energy Demand Management Based Multi-Criteria Decision Making Methods
Authors: Muhsen Dhiaa Halboot , Haider Haider Tarish , Al-Nidawi Yaarob , Khatib Tamer
Published: May 2019

From the growth of residential energy demands has emerged new approaches for load scheduling to realize better energy consumption by shifting the required demand in response to cost changes or incentive offers. In this paper, a hybrid method is proposed to optimize the load scheduling problem for cost and energy saving. The method comprises a multi-objective optimization differential evolution (MODE) algorithm to obtain a set of optimal solutions by minimizing the cost and peak of a load simultaneously, as a multi-objective function. Next, an integration of the analytic hierarchy process (AHP) and a technique for order preferences by similarity to ideal solution (TOPSIS) methods are used as multi-criteria decision making (MCDM) methods for sorting the optimal solutions’ set from the best to the worst, to enable the customer to choose the appropriate schedule time. The solutions are sorted based on the load peak and energy cost as multi-criteria. Data are for ten appliances of a household used for 24 h with a one-minute time slot. The results of the proposed method demonstrate both energy and cost savings of around 47% and 46%, respectively. Furthermore, the results are compared with other recent methods in the literature to show the superiority of the proposed method.
Design of a 41.14–48.11 GHz Triple Frequency Based VCO
Authors: Nasri Abbas , Toofan Siroos , Estebsari Motahhareh , Estebsari Abouzar
Published: May 2019

Growing deployment of more efficient communication systems serving electric power grids highlights the importance of designing more advanced intelligent electronic devices and communication-enabled measurement units. In this context, phasor measurement units (PMUs) are being widely deployed in power systems. A common block in almost all PMUs is a phase locked oscillator which uses a voltage controlled oscillator (VCO). In this paper, a triple frequency based voltage controlled oscillator is presented with low phase noise and robust start-up. The VCO consists of a detector, a comparator, and triple frequency. A VCO starts-up in class AB, then steadies oscillation in class C with low current oscillation. The frequency of the VCO, which is from 13.17 GHz to 16.03 GHz, shows that the frequency is tripling to 41.14–48.11 GHz. Therefore, its application is not limited to PMUs. This work has been simulated in a standard 0.18 µm CMOS process. The simulated VCO achieves a phase noise of −99.47 dBc/Hz at 1 MHz offset and −121.8 dBc/Hz at 10 MHz offset from the 48.11 GHz carrier.
A Novel Audio Encryption Algorithm with Permutation-Substitution Architecture
Authors: Kordov Krasimir
Published: May 2019

In this paper, a new cryptographic method is proposed, designed for audio files’ security. The encryption algorithm is based on classic symmetric models using pseudo-random number generator composed with chaotic circle map and modified rotation equations. The scheme of a new pseudo-random generator is presented and used as basis for chaotic bit-level permutations and substitutions applied to audio files structure for successful encryption. The audio encryption and decryption algorithms are described and explained. Proving the high level of security we provide extensive cryptographic analysis including key sensitivity analysis, key-space analysis, waveform and spectrogram analysis, correlation analysis, number of sample change rate analysis, level of noise analysis and speed performance test.
Considerations Regarding the Design of a Minimum Variance Control System for an Induction Generator
Authors: Filip Ioan , Mihet-Popa Lucian , Vasar Cristian , Prostean Octavian , Szeidert Iosif
Published: May 2019

This paper presents a comparative analysis regarding a self-tuning minimum variance control system of a double-fed induction generator with load and connected to a power system through a long transmission line. A new complex nonlinear model describing this relationship between the induction generator, electrical consumer, transmission line, and power system is designed and implemented to simulate the controlled plant behavior. Starting from a simplified linear model of this complex plant, obtained through linearization of its nonlinear model around an operating point, the minimum variance control law design is performed by minimizing a cost criterion function. The main goal and also the paper novelty consists of the identification of a minimum order of this linearized model used to design a reduced order control law, which can still provide good control performance.
Chaotic Pattern Array for Single-Pixel Imaging
Authors: Gan Hongping , Xiao Song , Zhang Tao , Zhang Zhimin , Li Jie , Gao Yang
Published: May 2019

Single-pixel imaging (SPI) is an emerging framework that can capture the image of a scene via a single-point detector at a considerably low cost. It measures the projection at the detector of the scene under view with certain patterns. One can reconstruct the image of the scene via post-processing the measurements modulated by the patterns. However, the most commonly-used random patterns are not always desirable in many applications, especially for real-time, resource-limited occasions, due to their high memory requirement and huge cost in software and hardware implementation. In this paper, a chaotic pattern array is proposed for the SPI architecture. Compared with random patterns, the proposed chaotic pattern array can not only promise to increase the capabilities of the SPI device, but can also reduce the memory cost and complexity of hardware implementation in the meantime. Moreover, convincing experiment results are given to illustrate that the proposed pattern array is suitable for single-pixel cameras, as well as other compressive imaging applications.
Effect of lateral Gate Design on the Performance of Junctionless Lateral Gate Transistors
Authors: Larki Farhad , Islam Md Shabiul , Dehzangi Arash , Tariqul Islam Mohammad , Wong Hin Yong
Published: May 2019

In this paper, we investigate the effect of lateral gate design on performance of a p-type double lateral gate junctionless transistors (DGJLTs) with an air gate gap. The impact of lateral gate length, which modifies the real channel length of the device and gate gap variation down to 50 nm which have been found to be the most influential factors in the performance of the device have been comprehensively investigated. The characteristics are demonstrated and compared with a nominal DGJLTs through three-dimensional technology computer-aided design (TCAD) simulation. At constant channel geometry (thickness and width), when the lateral gate length decreases, the results show constant flatband drain current characteristics while the OFF state current (IOFF) increases significantly. On the other hand, by decreasing the air gap the subthreshold current considerably decreases while the flatband current is constant. Moreover, at a certain gate gap, the gates lose control over the channel and the device simply works as a resistor. Electric field component, carriers’ density, band edge energies, and recombination rate of the carriers inside the channel in depletion and accumulation regimes are analysed to interpret the variation of output characteristics.
Analysis and Design of an Energy Verification System for SC200 Proton Therapy Facility
Authors: Wang Pengyu , Zheng Jinxing , Song Yuntao , Zhang Wuquan , Wang Ming
Published: May 2019

The purpose of this study is to provide an energy verification method for the nozzle of the SC200 proton therapy facility to ensure safe redundancy of treatment. This paper first introduces the composition of the energy selection system of the SC200 proton therapy facility. Secondly, according to IEC60601 standard, the energy verification requirement that correspond to 1 mm error in water is presented. The allowable difference between the measured magnetic field and the reference are calculated based on the energy verification requirements to select the field resolution of the Hall probe. To ensure accuracy and stability, two Hall probes are mounted on the dipole to monitor the magnetic field strength to verify the proton beam energy in real time. In addition, the test results of the residual field of the dipole show that the probe system meets the accuracy requirements of energy verification. Furthermore, the maximum width of the slit of the energy selection system in accordance with the IEC standard at the corresponding energy is calculated and compared with the actual position of the movable slit to verify the momentum divergence of the proton beam. Finally, we present an energy verification method.
Analysis and Optimization of Exergy Flows inside a Transcritical CO2 Ejector for Refrigeration, Air Conditioning and Heat Pump Cycles
Authors: Taslimi Taleghani Sahar , Sorin Mikhail , Poncet Sébastien
Published: May 2019

In this study, the exergy analysis of a CO2 (R744) two-phase ejector was performed using a 1D model for both single and double choking conditions. The impact of the back pressure on the exergy destruction and exergy efficiencies was presented to evaluate the exergy performance under different working conditions. The results of two exergy performance criteria (transiting exergy efficiency and Grassmann exergy efficiency) were compared for three modes of an ejector functioning: Double choking, single choking and at the critical point. The behavior of three thermodynamic metrics: Exergy produced, exergy consumed and exergy destruction were evaluated. An important result concerning the ejector’s design was the presence of a maximum value of transiting exergy efficiency around the critical point. The impact of the gas cooler and evaporator pressure variations on the different types of exergy, the irreversibilities and the ejector global performance were investigated for a transcritical CO2 ejector system. It was also shown that the transiting exergy flow had an important effect on the exergy analysis of the system and the Grassmann exergy efficiency was not an appropriate criterion to evaluate a transcritical CO2 ejector performance.
Application of Acoustic Emission Technique to the Evaluation of Coal Seam Hydraulic Flushing Effect
Authors: Shen Rongxi , Zhang Xuan , Wang Enyuan , Li Hongru , Han Xu , Hou Zhenhai
Published: May 2019

Hydraulic flushing has the advantages of reducing coal stress and improving coal seam permeability, so it is widely used in high gas outburst coal seams in China. However, the effect evaluation of stress relief and permeability enhancement will be necessary before coal mining. In this paper, an acoustic emission (AE) experiment system of coal seam hydraulic flushing was established, and the AE characteristics of coal during hydraulic flushing were studied. The results show that the changes in AE signals are basically consistent with those in load and water pressure. In addition, the quantitative relationship between the signals and the damage of coal around the borehole is revealed by the theory of damage mechanics. The in-situ AE test of hydraulic flushing was performed in the Liangbei Coal Mine, by measuring gas flow and coal stress simultaneously. The variation of AE activities and the effect evaluation of hydraulic flushing were analyzed. The results reveal that the changes in coal seam stress are basically consistent with those of AE signals. After the flushing has been completed for 1–3 h, the coal seam stress decreases rapidly, and the AE counts and intensity reach the peak. Therefore, this study proposes a new method for evaluating the effect of coal seam hydraulic flushing by AE, which has a very important practical significance.
Large-Scale Experiments to Improve Monopile Scour Protection Design Adapted to Climate Change—The PROTEUS Project
Authors: Arboleda Chavez Carlos Emilio , Stratigaki Vasiliki , Wu Minghao , Troch Peter , Schendel Alexander , Welzel Mario , Villanueva Raúl , Schlurmann Torsten , De Vos Leen , Kisacik Dogan , Taveira Pinto Francisco , Fazeres-Ferradosa Tiago , Rosa Santos Paulo , Baelus Leen , Szengel Viktoria , Bolle Annelies , Whitehouse Richard , Todd David
Published: May 2019

This study aims to improve the design of scour protection around offshore wind turbine monopiles, as well as future-proofing them against the impacts of climate change. A series of large-scale experiments have been performed in the context of the European HYDRALAB-PLUS PROTEUS (Protection of offshore wind turbine monopiles against scouring) project in the Fast Flow Facility in HR Wallingford. These experiments make use of state of the art optical and acoustic measurement techniques to assess the damage of scour protections under the combined action of waves and currents. These novel PROTEUS tests focus on the study of the grading of the scour protection material as a stabilizing parameter, which has never been done under the combined action of waves and currents at a large scale. Scale effects are reduced and, thus, design risks are minimized. Moreover, the generated data will support the development of future scour protection designs and the validation of numerical models used by researchers worldwide. The testing program objectives are: (i) to compare the performance of single-layer wide-graded material used against scouring with current design practices; (ii) to verify the stability of the scour protection designs under extreme flow conditions; (iii) to provide a benchmark dataset for scour protection stability at large scale; and (iv) to investigate the scale effects on scour protection stability.
Evaluation of the Use of Energy in the Production of Sweet Sorghum (Sorghum Bicolor (L.) Moench) under Different Production Systems
Authors: López-Sandin Iosvany , Gutiérrez-Soto Guadalupe , Gutiérrez-Díez Adriana , Medina-Herrera Nancy , Gutiérrez-Castorena Edgar , Zavala-García Francisco
Published: May 2019

The growing global demand for energy and the reduction of energy based on oil are driving the search for new sources of energy that are environmentally friendly. To achieve this goal, it is also necessary to optimize the related processes. In this study, the behavior of the agronomic parameters of, and the energy invested in, production systems based on a new variety of sweet sorghum (Sorghum bicolor (L.) Moench) called ROGER were determined to define the optimal production conditions. To this end, three methods of tillage (minimum, traditional, and traditional tillage with rupture of the plow layer) and three types of fertilizers (inorganic, organic, and without fertilizer) were established, and to estimate the energy efficiency, the inputs and the energy outputs of each system were considered. The traditional tillage with breaking of the plow layer and the organic fertilizer showed the highest values of plant height (2.45 and 2.39 m, respectively); total fresh weight of the plant (51.66 and 50.77 t·ha−1, respectively), of the stem (42.7 and 41.05 t·ha−1, respectively), and of the juice (21.89 and 22.57 t·ha−1, respectively); the volume of the juice (20,783.12 and 22,529.59 L·ha−1, respectively); and Brix degrees (16.04% and 15.01%, respectively). However, the highest energy efficiency was registered in the production system that used the minimum tillage, with a value of 15.11, as well as when no fertilizer was applied with 18.68.
Fault-Tolerant Control Strategies and Capability without Redundant Sub-Modules in Modular Multilevel Converters
Authors: Li Jinke , Yin Jingyuan
Published: May 2019

Sub-module (SM) faults in modular multilevel converters (MMCs) without redundancies result in unbalanced converter output voltages and improper control of modulation due to an unequal number of SMs inserted between the different phase-legs. The derived mathematics model of the MMC demonstrates the impact of the SM fault in the circulating currents and capacitor voltages. For achieving the SM fault-tolerance, detailed analysis of the MMC’s electrical quantities under SM fault-tolerant algorithms is provided together with two modulation reconfiguration techniques for maintaining voltage balance. Fault-tolerant abilities of the two modulation algorithms are also discussed and defined. Simulation results from a 21-level converter and experimental work in a three-phase five-level converter demonstrate the feasibility and performance of the proposed fault-tolerant control strategies.
Optimal Sizing of Photovoltaic Generation in Radial Distribution Systems Using Lagrange Multipliers
Authors: Costa José Adriano da , Castelo Branco David Alves , Pimentel Filho Max Chianca , Medeiros Júnior Manoel Firmino de , Silva Neilton Fidelis da
Published: May 2019

The integration of renewable distributed generation into distribution systems has been studied comprehensively, due to the potential benefits, such as the reduction of energy losses and mitigation of the environmental impacts resulting from power generation. The problem of minimizing energy losses in distribution systems and the methods used for optimal integration of the renewable distributed generation have been the subject of recent studies. The present study proposes an analytical method which addresses the problem of sizing the nominal power of photovoltaic generation, connected to the nodes of a radial distribution feeder. The goal of this method is to minimize the total energy losses during the daily insolation period, with an optimization constraint consisting in the energy flow in the slack bus, conditioned to the energetic independence of the feeder. The sizing is achieved from the photovoltaic generation capacity and load factors, calculated in time intervals defined in the typical production curve of a photovoltaic unit connected to the distribution system. The analytical method has its foundations on Lagrange multipliers and relies on the Gauss-Jacobi method to make the resulting equation system solution feasible. This optimization method was evaluated on the IEEE 37-bus test system, from which the scenarios of generation integration were considered. The obtained results display the optimal sizing as well as the energy losses related to additional power and the location of the photovoltaic generation in distributed generation integration scenarios.
Review and Mapping of Parameters for the Early Stage Design of Adaptive Building Technologies through Life Cycle Assessment Tools
Authors: Battisti Alessandra , Persiani Sandra G. L. , Crespi Manuela
Published: May 2019

Adaptive Building Technologies have opened up a growing field of architectural research aimed at improving the overall building performance, ensuring comfort while reducing operational energy consumption. Focusing on flexibility over short timeframes, these new technologies are however rarely designed within the broader frame of sustainability over their entire lifecycle. How sustainable these zero energy technologies really are is yet to be established. The purpose of the research is to develop a flexible easy-to-use Life Cycle Assessment (LCA) tool to support creative innovation and sustainable design choices in the early concept and design stages of Adaptive Building Technologies. This paper reports on the results of the first step of the research, providing a mapping in terms of structure and contents of the parameters involved in the design of these technologies. Addressed from a holistic point of view, the elements of the system were defined though a qualitative approach: relevant parameters were collected through document analysis, reviewing the state-of-the-art technology through online databases as ScienceDirect, Scopus, MDPI, ResearchGate, and organized according to hierarchy and relevance in the different life cycle stages. As a result, the paper identifies (1) relevant parameters defining the design of Adaptive Building Technologies; (2) materials, processes and concepts specific to the design of these technologies, as compared to conventional building technologies; (3) issues and knowledge gaps to enable successive research phases; (4) specific actions in each life cycle stage for designers and producers to optimize the design of the technology. The mapping graphically and hierarchically organizes the elements of the system within a flexible structure to be implemented and integrated over time, as the technology evolves, to support parametric design and enable alternative design concepts to arise within a cradle-to-cradle perspective.
Synthesis of Novel Ethoxylated Quaternary Ammonium Gemini Surfactants for Enhanced Oil Recovery Application
Authors: Hussain S. M. Shakil , Kamal Muhammad Shahzad , Murtaza Mobeen
Published: May 2019

Two aspects are always considered in the design and development of new surfactants for oilfield application. One of them is that surfactant must be sufficiently stable at reservoir temperature and the other is the solubility of the surfactant in the injection water (usually seawater) and the formation brine. Most industrially applied surfactants undergo hydrolysis at elevated temperature and the presence of reservoir ions causes surfactant precipitation. In relevance to this, a novel series of quaternary ammonium gemini surfactants with different length of spacer group (C8, C10, and C12) was synthesized and characterized using FT-IR, 13C NMR, 1H NMR, and MALDI-TOF MS. The gemini surfactants were prepared by solvent-free amidation of glycolic acid ethoxylate lauryl ether with 3-(dimethylamino)-1-propylamine followed by reaction with dibromoalkane to obtain quaternary ammonium gemini surfactants. The gemini surfactants were examined by means of surface properties and thermal stabilities. The synthesized gemini surfactants showed excellent solubility in the formation brine, seawater, and deionized water without any precipitation for up to three months at 90 °C. Thermal gravimetric data revealed that all the gemini surfactants were decomposed above 227 °C, which is higher than the oilfield temperature (≥90 °C). The decrease in critical micelle concentration (CMC) and surface tension at CMC (γcmc) was detected by enhancing spacer length in the order C8 ˃ C10 ˃ C12 which suggested that the larger the spacer, the better the surface properties. Moreover, a further decrease in CMC and γcmc was noticed by enhancing temperature (30 °C ˃ 60 °C) and salinity (deionized water ˃ seawater). The current study provides a comprehensive investigation of quaternary ammonium gemini surfactants that can be further extended potentially to use as a suitable material for oilfield application.
Forced Combustion Characteristics Related to Different Injection Locations in Unheated Supersonic Flow
Authors: Kim Chae-Hyoung , Jeung In-Seuck
Published: May 2019

This work focuses on forced combustion with regards to the relationship between vent mixer models and several injection locations in unheated supersonic flow. A plasma jet torch was used to ignite the hydrogen-air mixture in a laboratory-scaled combustor duct. The flow field of the combustion was visualized with pressure and gas-sampling measurements. The vent mixers indicate good dispersion characteristics of the mixture for both parallel and normal 1 injections. However, forced combustion is dominantly governed by the injection rate toward the plasma jet (hot source) because the combustible region is restricted under the cold main flow. For this reason, the parallel injection, which provides the hydrogen-air mixture directly toward the plasma jet, shows good combustion performance. The normal 1 injection interacted with the vent mixers and shows slightly good combustion performance. Lastly, the normal 2 injection is little affected by the vent mixers and has poor combustion performance.
A Review of Criticisms of Integrated Assessment Models and Proposed Approaches to Address These, through the Lens of BECCS
Authors: Gambhir Ajay , Butnar Isabela , Li Pei-Hao , Smith Pete , Strachan Neil
Published: May 2019

This paper reviews the many criticisms that Integrated Assessment Models (IAMs)—the bedrock of mitigation analysis—have received in recent years. Critics have asserted that there is a lack of transparency around model structures and input assumptions, a lack of credibility in those input assumptions that are made visible, an over-reliance on particular technologies and an inadequate representation of real-world policies and processes such as innovation and behaviour change. The paper then reviews the proposals and actions that follow from these criticisms, which fall into three broad categories: scrap the models and use other techniques to set out low-carbon futures; transform them by improving their representation of real-world processes and their transparency; and supplement them with other models and approaches. The article considers the implications of each proposal, through the particular lens of how it would explore the role of a key low-carbon technology—bioenergy with carbon capture and storage (BECCS), to produce net negative emissions. The paper concludes that IAMs remain critically important in mitigation pathways analysis, because they can encompass a large number of technologies and policies in a consistent framework, but that they should increasingly be supplemented with other models and analytical approaches.
Optimal Coordinated Bidding of a Profit Maximizing, Risk-Averse EV Aggregator in Three-Settlement Markets Under Uncertainty
Authors: Vardanyan Yelena , Madsen Henrik
Published: May 2019

This paper develops a two-stage stochastic and dynamically updated multi-period mixed integer linear program (SD-MILP) for optimal coordinated bidding of an electric vehicle (EV) aggregator to maximize its profit from participating in competitive day-ahead, intra-day and real-time markets. The hourly conditional value at risk (T-CVaR) is applied to model the risk of trading in different markets. The objective of two-stage SD-MILP is modeled as a convex combination of the expected profit and the T-CVaR hourly risk measure. When day-ahead, intra-day and real-time market prices and fleet mobility are uncertain, the proposed two-stage SD-MILP model yields optimal EV charging/discharging plans for day-ahead, intra-day and real-time markets at per device level. The degradation costs of EV batteries are precisely modeled. To reflect the continuous clearing nature of the intra-day and real-time markets, rolling planning is applied, which allows re-forecasting and re-dispatching. The proposed two-stage SD-MILP is used to derive a bidding curve of an aggregator managing 1000 EVs. Furthermore, the model statistics and computation time are recorded while simulating the developed algorithm with 5000 EVs.
Facies and the Architecture of Estuarine Tidal Bar in the Lower Cretaceous Mcmurray Formation, Central Athabasca Oil Sands, Alberta, Canada
Authors: Tang Mingming , Zhang Kexin , Huang Jixin , Lu Shuangfang
Published: May 2019

In this study, data obtained from the Lower Cretaceous McMurray Formation in the central Athabasca Oil Sands, northeastern Alberta, Canada, are examined and used to establish the architecture of stacked fluvial and estuarine tidal bar deposits. A total of 13 distinguishable facies (F1–F7, F8a–F8b, and F9–F13) corresponding to stacked fluvial and estuarine deposits are recognized. These facies are then reassembled into four facies associations: fluvial deposits, tidal flat, tidal bar complex, and tidal bar cap. Of these, the lower fluvial deposits show a highly eroded channel lag and tidal influences in the cross-stratified sand and wavy interbeds. The fluvial deposits pass upwards into upper tidal-dominated tidal flats and a massive homogeneous tidal sand bar complex. Very thick tidal-influenced facies (F8a–F8b, up to 22 m) caused by semi-diurnal and semi-lunar cycles are also observed in tidal flats. Based on studies of the facies and facies associations, a three-dimensional (3-D) architecture model is finally established and used to analyze the internal distribution of the stacked fluvial and estuarine deposits. This is the first time that a 3-D model of the paleo-estuary tidal bar has been constructed. The results of this study will assist future research analyzing the architecture of stacked fluvial and estuarine deposits.
Performance Optimization of a Kirsten–Boeing Turbine by A Metamodel Based on Neural Networks Coupled with CFD
Authors: Küppers Jan-Philipp , Metzger Jens , Jensen Jürgen , Reinicke Tamara
Published: May 2019

The supply of energy is sustainable only if it is predominantly based on renewable or regenerative energies. For this reason, the use of micro-hydropower plants on rivers and streams is considered recently. This is a particular challenge for the preservation of ecologically permeable streams, so that no dams or similar structures can be considered. While the axial turbine design has prevailed in wind power, there is still no consensus for the generation of energy in free water flow conditions. In this work, an existing prototype of an unusual vertical axis Kirsten–Boeing turbine was investigated. A multivariate optimization process was created, in which all important machine parameters were checked and improved. By using neural networks as a metamodel coupled with flow simulations in ANSYS CFX, a broadly applicable optimization strategy is presented that yielded a blade design that is 36% more efficient than its predecessor in experiments. During the process, it was shown how to set up a complex sliding mesh problem with ANSYS expressions while evaluating a free surface problem.
High-Frequency LLC Resonant Converter with GaN Devices and Integrated Magnetics
Authors: Liu Yu-Chen , Chen Chen , Chen Kai-De , Syu Yong-Long , Tsai Meng-Chi
Published: May 2019

In this study, a light emitting diode (LED) driver containing an integrated transformer with adjustable leakage inductance in a high-frequency isolated LLC resonant converter was proposed as an LED lighting power converter. The primary- and secondary-side topological structures were analyzed from the perspectives of component loss and component stress, and a full-bridge structure was selected for both the primary- and secondary-side circuit architecture of the LLC resonant converter. Additionally, to achieve high power density and high efficiency, adjustable leakage inductance was achieved through an additional reluctance length, and the added resonant inductor was replaced with the transformer leakage inductance without increasing the amount of loss caused by the proximity effect. To optimize the transformer, the number of primary- and secondary-side windings that resulted in the lowest core loss and copper loss was selected, and the feasibility of the new core design was verified using ANSYS Maxwell software. Finally, this paper proposes an integrated transformer without any additional resonant inductor in the LLC resonant converter. Transformer loss is optimized by adjusting parameters of the core structure and the winding arrangement. An LLC resonant converter with a 400 V input voltage, 300 V output voltage, 1 kW output power, and 500 kHz switching frequency was created, and a maximum efficiency of 97.03% was achieved. The component with the highest temperature was the transformer winding, which reached 78.6 °C at full load.
Energy Performance Comparison between Liquid-Desiccant-Assisted Air Conditioning System and Dedicated Outdoor Air System in Different Climatic Regions
Authors: Liu Su , No Sang-Tae , Jeong Jae-Weon
Published: May 2019

The main purpose of this research is to analyze and compare the energy performance of two different novel air conditioning systems; one is a dedicated outdoor air system (DOAS) with a parallel system and the other is a heat-pump-integrated liquid-desiccant and evaporative-cooling-assisted 100% outdoor air system (HPLD-IDECOAS). It was assumed that office buildings served by each system were located in six cities representing four different climatic regions in China. The hourly thermal loads of the office buildings meeting the local building design codes of each selected city were predicted by the TRNSYS 18 software package. The hourly thermal load data were imported into the commercial engineering equation solver (EES) program to estimate the operating energy consumption of each system via detailed energy simulations performed using valid system simulation models. The results show that the HPLD-IDECOAS has higher energy-saving potential than the DOAS with a parallel system in climate regions with high humidity, whereas, in dry regions, the difference in energy consumption between the two systems was not significant.
Design and Simulation of an Energy Homeostaticity System for Electric and Thermal Power Management in a Building with Smart Microgrid
Authors: Parejo Antonio , Sanchez-Squella Antonio , Barraza Rodrigo , Yanine Fernando , Barrueto-Guzman Aldo , Leon Carlos
Published: May 2019

Nowadays, microgrids are gaining importance in electric power generation and distribution environments due to their flexibility, versatility, scalability and the possibility of supplying ancillary services when connected to the grid. They allow for the customization of electric supply for very different types of consumers. Therefore, a new control model for power and energy management based on homeostaticity of electric power systems (EPS) is presented, which has been already analyzed and approved by ENEL Chile in its developmental stage. ENEL, the largest electric utility in the country, is interested in incorporating smart microgrids in the electricity distribution market, as part of a worldwide policy. Such microgrids are to be installed in buildings serviced by ENEL. To demonstrate the model’s utility, a Simulink model of a real microgrid is used, which is comprised of PV generation, energy storage, an air conditioning (AC) equipment and thermal storage of the building upon which the microgrid is installed. The behavior of every element is simulated, including the dynamic thermal model of the building in order to optimize energy management and power supply versus consumption. The behavior of the whole system is analyzed under different environmental profiles and energy consumption patterns using the proposed homeostaticity system.
Urban Ecosystem Services Quantification through Remote Sensing Approach: A Systematic Review
Authors: Tavares Paulo Amador , Beltrão Norma , Guimarães Ulisses Silva , Teodoro Ana , Gonçalves Paulo
Published: May 2019

Urban ecosystem services (UES) is an essential approach to the development of sustainable cities and must be incorporated into urban planning to be able to improve humans’ life quality. This paper aimed to identify remote sensing (RS) data/techniques used in the literature in five years (2013–2017) for UES investigation and to analyze the similarity between them. For this purpose, we used the Scopus database of scientific journals, and a set of appropriate filters were applied. A total of 44 studies were selected, being 93.18% of them located in the Northern Hemisphere, mostly in Europe. The most common dataset used was the secondary data, followed by the Landsat family products. Land use and land cover (LULC) was the most common approach utilized, succeeded by radiometric indexes and band related. All four main classes (provision, regulation, supporting, and cultural) of ecosystem services (ES) were identified in the reviewed papers, wherein regulating services were the most popular modality mentioned. Seven different groups were established as having 100% of similarity between methods and ES results. Therefore, RS is identified in the literature as an important technique to reach this goal. However, we highlight the lack of studies in the southern hemisphere.
Contribution of Mangrove Forest to the Livelihood of Local Communities in Ayeyarwaddy Region, Myanmar
Authors: Aye Wai Nyein , Wen Yali , Marin Kim , Thapa Shivaraj , Tun Aung W.
Published: May 2019

Myanmar’s forests are socially and economically significant to the country because over 70% of the country’s population depends on natural resources for daily needs. We conducted this study with the aim of assessing the extent to which direct and indirect (tangible) benefits of mangrove forest contribute to local livelihoods in the Ayeyarwaddy Region, Myanmar. We used a questionnaire survey (n = 185 households), interview and group discussion for data collection. The study shows that 43% of total household income is generated through selling of forest products collected from the mangrove forest such as firewood, fishes, crabs and prawn, whereas agricultural and non-farm incomes were found to be 25% and 32% of total income, respectively. The result prevails that income from the mangrove forest products for fish, crab, prawn and firewood is specifically 36%, 28%, 9% and 27%, respectively. Hence, we confirmed that local livelihood mainly depends on the mangrove forest ecosystem.