Academic literature on the topic 'Active Front End Converters'

Modular multilevel converters (MMCs) have been conceived as an alternative in front-end converter applications to enhance the converter system’s reliability, minimize total harmonic distortion, and improve power quality. These converters utilize several DC-link capacitors and power electronic switches, along with switches operating with high switching frequencies, to attain the desired characteristics. Thereby, this paper systematically proposes a novel three-phase asymmetric hybrid modular multilevel converter (AHMMC) for front-end converters used in lower-medium-voltage applications. The AHMMC configuration is based on a three-phase converter connected to a per-phase series arrangement with a cascaded converter module (CCM). The study investigates the AHMMC and proposes a control scheme, which minimizes the voltage range on switches and maintains the current to its reference value. Furthermore, the study also introduces an active balancing of voltage across DC-link capacitors based on the phase opposition disposition PWM (POD-PWM) method. Our new configuration has features such as low switching loss, reduced DC-link voltage, a wider modulation range for the unity power factor (PF), and low voltage and current harmonic distortion. The simulation results are added to verify the performance of the new AHMMC topology and the usefulness of the modular control scheme. In addition, a low-voltage laboratory prototype based on customized control and power boards is built to validate the proposed converter and its control scheme in practice.

Grid integrated photovoltaic (PV) system is capable of maximizing solar energy conversion by minimizing power losses. Conventionally, the grid integrated PV system uses boost or buck-boost DC-DC converters in the DC link for lifting up the PV output. Also, a separate complex circuit is used for active power compensation in the grid end. This paper proposes an advanced DC-DC converter by name Super-Lift Converter (SLC) in the DC link of grid integrated PV system. Unlike the conventional DC-DC converters, the proposed converter lifts up the DC link voltage thrice that of the input voltage. In addition, the proposed SLC is regulated using a PI controlled active front end (AFE) topology, which results in operation of unity power factor at grid end. The suggested system is simulated using MATLAB software. The presented results such as grid end voltage and current, input and output power of SLC and DC link voltage validates the effectiveness of the developed system.

This paper addresses the issue of functional possibilities of reversible electric drive based on active front end rectifier and voltage source inverter from the point of view of energy saving. This paper will review all theoretical capabilities of reactive power compensation in the supply mains by the active front end rectifiers. The reactive power consumption or generation can be created out by using of active front end converters which connect the electric drive with supply mains. Active front end rectifiers can be actively used in operation of supply mains of enterprise as they are able to provide controlled power factor and bidirectional power flow. The studies by mathematical modeling in the Matlab/Simulink program were carried out. It was established that the controlling of power factor of active front end rectifier can be used for reactive power compensation in supply mains. The huge prospects of energy-saving reversible electric drive integration to the Smart Grid have been determined as it is able to provide high power and capabilities of the controlling reactive power flow by means of active front end rectifier. It can reduce a share of the consumption reactive power from a substation and to improve the power quality.

The dissertation presents a generalized average-current-mode control technique (GACMC), which is an extension of the average-current-mode control (ACMC) for single-phase ac-dc boost converters with power factor correction (PFC). Traditional ACMC is generalized in a sense that it offers improved performance in the form of significant reduction of the current control loop bandwidth requirement for a given line frequency in unidirectional and bidirectional boost PFC converters, and additional functionality in the form of reactive power control capability in bidirectional converters. These features allow using a relatively low switching frequency and slow-switching power devices such as insulated-gate bipolar transistors (IGBTs) in boost PFC converters, including those designed for higher ac line frequencies such as in aircraft power systems (360â 800 Hz). In bidirectional boost PFC converters, including multilevel topologies, the GACMC offers a capability to supply a prescribed amount of reactive power (with leading or lagging current) independently of the dc load power, which allows the converter to be used as a static reactive power compensator in the power system.

A closed-loop dynamic model for the current control loop of the boost PFC converter with the ACMC has been developed. The model explains the structure of the converter input admittance, the current phase lead phenomenon, and lays the groundwork for development of the GACMC. The leading phase admittance cancellation (LPAC) principle has been proposed to completely eliminate the current phase lead phenomenon and, consequently, the zero-crossing distortion in unidirectional converters. The LPAC technique has been adapted for active compensation of the input filter capacitor current in bidirectional boost PFC converters.

The dynamic model of the current control loop for bidirectional boost PFC converters was augmented to include a reactive power controller. The proposed control strategy enables the converter to process reactive power and, thus, be used as a reactive power compensator, independently of the converter operation as an ac-dc converter.

Multiple realizations of the reactive power controller have been identified and examined in a systematic way, along with their merits and limitations, including susceptibility to the ac line noise. Frequency response characteristics of reactive elements emulated by means of these realizations have been described.

Theoretical principles and practical solutions developed in this dissertation have been experimentally verified using unidirectional and bidirectional converter prototypes. Experimental results demonstrated validity of the theory and proposed practical implementations of the GACMC.
Ph. D.

University of Central Florida College of Engineering Thesis
Evolution in microprocessor technology poses new challenges for supplying power to these devices. To meet demands for faster and more efficient data processing, modem microprocessors are being designed with lower voltage implementations. More devices will be packed on a single processor chip and the processors will operate at higher frequencies, exceeding IGHz. New high performance microprocessors may require from 40 to 80 watts of power for the CPU alone. Load current must be supplied with up to 30A/us slew rate while keeping the output voltage within tight regulation and response time tolerances. Therefore, special power supplies and Voltage Regulator Modules (VRMs) are needed to provide lower voltage with higher current and fast response.
Ph.D.
Doctorate;
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering and Computer Science
124 p.
xii, 124 leaves, bound : ill. ; 28 cm.

The next generation High Energy Physics experiments require the development of novel radiation sensor technologies adequate to cover very large areas and suitable for extreme radiation conditions. In this field, thanks to its incomparable properties, silicon is still nowadays the dominant semiconductor used to build tracking detectors for ionizing particles. In several experiments all around the world, it is used to cover very large areas with the intent of tracking and identifying the crossing particles generated during the experiments. Different topologies of silicon sensors can be used for these applications but those commonly used for high rate environments are pixel sensors. This research activity focuses mainly on two particular types of these sensors: hybrid pixel sensors and monolithic active pixel sensors (MAPS). Modern detectors use intensively hybrid sensors due to their excellent properties. This technology indeed allows to develop sensor and electronics separately allowing a very effective optimization of each part of the device increasing in this way its versatility and allowing to meet most of the requirements of the new experiments. The hybrid technology is fast and also suitable for working in high radiation environments thanks to the use of high electrical fields for the charge collection. However, the production cost of those devices is much higher than other sensors because two different devices are required and also due to the additional cost for the bump bonding used to interconnect sensor and readout ASIC. On the other hand, monolithic sensors are based on the implementation of sensor and readout electronics in the same silicon wafer. Therefore this technology is much cheaper than the hybrid solution and allows to reduce significantly contribution of the detector to the material budget. However, traditional MAPS have some limitations in terms of speed, extension of the depletion volume, signal to noise ratio and radiation tolerance which make those devices unsuitable for the extreme environment of the new experiments. In this context, this work presents the development of a full depleted monolithic pixel sensor with a thickness of 300 μm which aims to overcome the main limitations of the conventional monolithics. The proposed device has properties similar to the hybrid solution but benefits of the low production cost typical of monolithics. The development of the device has been carried out by the collaboration between the University of Trento, INFN of Padova and INFN of Torino. In addition, thanks to the close collaboration with the experts of a silicon foundry, it was possible a tailored fabrication of the devices. Two ASICs of 2 mm × 2 mm have been developed in a customized double-sided CMOS technology with transistors of 1.2 V and 6 metal layers. The devices have been submitted to the foundry for fabrication on April 2016 and have been delivered for the testing phase on May 2017. A patent for the device has been granted in 2017. In the first part of this work, the state of the art of monolithics is given where hybrid and monolithics are compared. Then, the novel sensor is described in detail with the support of simulations to motivate important solutions adopted to reach the full depletion and to implement PMOS transistors avoiding the competitive charge collection. Some studies to highlight the huge limitations on design MAPS without access to the process data are presented to introduce the custom process used for the development of the device. The first ASIC is a test chip designed to contain test devices used to study important properties of the sensor like depletion and punch-through voltage. All the devices implemented in this ASIC are described in detail motivating the design solutions adopted. The second ASIC is the complete monolithic sensor called MATISSE (Monolithic AcTIve pixel SenSor Electronics) made by a matrix array of 24 × 24 pixels readout with the snapshot shutter technique. Each pixel is 50 μm×50 μm and is based on the same novel sensor. The chip is described in detail with the support of simulation results to motivate some strategies adopted during the design. Special emphasis is placed on the strategy used to design the readout chain with a wide output swing, low noise and excellent linearity with the use of high threshold transistors. Last but not least, in the last chapter the results collected during the characterization of the two prototypes for different wafers are presented. The data acquisition system developed is described and the electrical tests and measurements with active sources and lasers are reported. The measurements performed on the test structures show unwanted trapped charge in the backside oxide. The phenomenon is described putting special attention on an irradiation campaign performed in the test diodes to confirm and quantify this effect. All the results presented in this work aim to prove the device full depletion and the excellent properties of the embedded electronics implemented in these first prototypes.

The spread of renewable energy sources and electric vehicles is increasing thanks to the greater awareness of the climate problems due to the large and long-lasting use of the non-renewable energy sources. The integration of renewable energy sources to the power grid, however, poses significant technical challenges, since it drastically changes its topology and nature. In fact, while the traditional power generation system is centralized, the renewable energy is distributed and intermittent. In this scenario, power converters play a central role. Power converters are the technology that enables the interconnection of different players to the electric power system. In this work, a control system for grid-connected converters has been developed. The main focus is on the current control. The most renowned current controllers, such resonant and repetitive regulators, have been studied and tested in laboratory in order to compare the performance in terms of harmonic compensation and burden of the processor. The problem of the saturation of a multi-frequency current controller has been investigated and different saturation algorithms have been proposed. The power converters have, however, wide use and the same of the method, developed for grid-connected converters can be applied to electrical motor drives with open-end windings. If a floating capacitor bridge is connected to the secondary side of the open-end stator windings, it can supply the reactive power needed by the motor and completely exploit its current capability of the power source. This feature allows the drive to obtain higher torque at higher speed, increasing therefore the output power over all the flux-weakening speed range. The floating bridge, operating as harmonic compensator, allows the inverter connected to the primary energy source to work in overmodulation and even six-step modulation, in order to further boost the performance of the drive, without compromising the quality of the phase current.

The trend in isolated DC/DC bus converters is to increase the output power in the same brick form factors that have been used in the past. Traditional intermediate bus converters (IBCs) use silicon power metal oxide semiconductor field effect transistors (MOSFETs), which recently have reached the limit in terms of turn on resistance (RDSON) and switching frequency. In order to make the IBCs smaller, the switching frequency needs to be pushed higher, which will in turn shrink the magnetics, lowering the converter size, but increase the switching related losses, lowering the overall efficiency of the converter. Wide-bandgap semiconductor devices are becoming more popular in commercial products and gallium nitride (GaN) devices are able to push the switching frequency higher without sacrificing efficiency. GaN devices can shrink the size of the converter and provide better efficiency than its silicon counterpart provides. A survey of current IBCs was conducted in order to find a design point for efficiency and power density. A two-stage converter topology was explored, with a multiphase buck converter as the front end, followed by an LLC resonant converter. The multiphase buck converter provides regulation, while the LLC provides isolation. With the buck converter providing regulation, the switching frequency of the entire converter will be constant. A constant switching frequency allows for better electromagnetic interference (EMI) mitigation. This work includes the details to design and implement a hard-switched multiphase buck converter with planar magnetics using GaN devices. The efficiency includes both the buck efficiency and the overall efficiency of the two-stage converter including the LLC. The buck converter operates with 40V - 60V input, nominally 48V, and outputs 36V at 1 kW, which is the input to the LLC regulating 36V – 12V. Both open and closed loop was measured for the buck and the full converter. EMI performance was not measured or addressed in this work.
Master of Science

Front-end converters with power factor correction (PFC) capability are widely used in distributed power systems (DPSs). Most of the front-end converters are implemented using a two-stage approach, which consists of a PFC stage followed by a DC/DC converter. The purpose of the front-end converter is to regulate the DC output voltage, supply all the load converters connected to the distributed bus, guarantee current sharing, and charge a bank of batteries to provide backup energy when the power grid breaks down. One of the main concerns of the power supply industry is to obtain a front-end converter with a low-cost PFC stage, while still complying with required harmonic standards, especially for high-power three-phase applications. Having this statement in mind, the main objective of this dissertation is to study front-end converters for DPS applications with PFC to meet harmonic standards, while still maintaining low cost and performance indices. To realize the many aforementioned objectives, this dissertation is divided into two main parts: (1) two-stage front-end converters suitable for telecom applications, and (2) single-stage low-cost AC/DC converters suitable for mainframe computers and server applications. The use of discontinuous conduction mode (DCM) boost rectifiers is extensively explored to achieve simplicity, while reducing the cost for DPS applications. Interleaving of DCM boost rectifiers is also explored as an alternative approach to further reduce the system cost by reducing the filtering requirements. All the solutions discussed are implemented for 3kW applications, while 6kW is obtained by interleaving two converters.
Ph. D.

The research presented in this thesis leverages silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) technology to develop microwave front-end electronics for active phased-array antennas. The highly integrated electronics will reduce costs and improve the feasibility of snow measurements from airborne and space-borne platforms. Chapter 1 presents the motivation of this research, focusing on the technological needs of snow measurement missions. The fundamentals and benefits of SiGe HBTs and phased-array antennas for these missions are discussed as well. Chapter 2 discusses SiGe power amplifier design considerations for radar systems. Basic power amplifier design concepts, power limitations in SiGe HBTs, and techniques for increasing the output power of SiGe HBT PAs are reviewed. Chapter 3 presents the design and characterization of a robust medium power X-band SiGe power amplifier for integration into a SiGe transmit/receive module. The PA design process applies the concepts presented in Chapter 2. A detailed investigation into measurement-to-simulation discrepancies is outlined as well. Chapter 4 discusses the development and characterization of a single-chip X-band SiGe T/R module for integration into a very thin, lightweight active phased array antenna panel. The system-on-package antenna combines the high performance and integration potential of SiGe technologies with advanced substrates and packaging techniques to develop a high performance scalable antenna panel using relatively low-cost materials and silicon-based electronics. The antenna panel presented in this chapter will enable airborne SCLP measurements and advance the technology towards an eventual space-based SCLP measurement instrument that will satisfy a critical Earth science need. Finally, Chapter 5 provides concluding remarks and discusses future research directions.

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1992.
Includes bibliographical references (leaves 181-184).
by Loveday Haachitaba Mweene.
Sc.D.

Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.
Dr. Chang-Ho Lee, Committee Member ; Dr . Kevin T Kornegay, Committee Member ; Dr. Emmanouil M Tentzeris, Committee Member ; Dr. Joy Laskar, Committee Chair ; Dr. Oliver Brand, Committee Member.

Nationalism: Past as Prologue began as a single volume being compiled by Ad Akande, a scholar from South Africa, who proposed it to me as co-author about two years ago. The original idea was to examine how the damaging roots of nationalism have been corroding political systems around the world, and creating dangerous obstacles for necessary international cooperation. Since I (Bruce E. Johansen) has written profusely about climate change (global warming, a.k.a. infrared forcing), I suggested a concerted effort in that direction. This is a worldwide existential threat that affects every living thing on Earth. It often compounds upon itself, so delays in reducing emissions of fossil fuels are shortening the amount of time remaining to eliminate the use of fossil fuels to preserve a livable planet. Nationalism often impedes solutions to this problem (among many others), as nations place their singular needs above the common good. Our initial proposal got around, and abstracts on many subjects arrived. Within a few weeks, we had enough good material for a 100,000-word book. The book then fattened to two moderate volumes and then to four two very hefty tomes. We tried several different titles as good submissions swelled. We also discovered that our best contributors were experts in their fields, which ranged the world. We settled on three stand-alone books:” 1/ nationalism and racial justice. Our first volume grew as the growth of Black Lives Matter following the brutal killing of George Floyd ignited protests over police brutality and other issues during 2020, following the police assassination of Floyd in Minneapolis. It is estimated that more people took part in protests of police brutality during the summer of 2020 than any other series of marches in United States history. This includes upheavals during the 1960s over racial issues and against the war in Southeast Asia (notably Vietnam). We choose a volume on racism because it is one of nationalism’s main motive forces. This volume provides a worldwide array of work on nationalism’s growth in various countries, usually by authors residing in them, or in the United States with ethnic ties to the nation being examined, often recent immigrants to the United States from them. Our roster of contributors comprises a small United Nations of insightful, well-written research and commentary from Indonesia, New Zealand, Australia, China, India, South Africa, France, Portugal, Estonia, Hungary, Russia, Poland, Kazakhstan, Georgia, and the United States. Volume 2 (this one) describes and analyzes nationalism, by country, around the world, except for the United States; and 3/material directly related to President Donald Trump, and the United States. The first volume is under consideration at the Texas A & M University Press. The other two are under contract to Nova Science Publishers (which includes social sciences). These three volumes may be used individually or as a set. Environmental material is taken up in appropriate places in each of the three books. * * * * * What became the United States of America has been strongly nationalist since the English of present-day Massachusetts and Jamestown first hit North America’s eastern shores. The country propelled itself across North America with the self-serving ideology of “manifest destiny” for four centuries before Donald Trump came along. Anyone who believes that a Trumpian affection for deportation of “illegals” is a new thing ought to take a look at immigration and deportation statistics in Adam Goodman’s The Deportation Machine: America’s Long History of Deporting Immigrants (Princeton University Press, 2020). Between 1920 and 2018, the United States deported 56.3 million people, compared with 51.7 million who were granted legal immigration status during the same dates. Nearly nine of ten deportees were Mexican (Nolan, 2020, 83). This kind of nationalism, has become an assassin of democracy as well as an impediment to solving global problems. Paul Krugman wrote in the New York Times (2019:A-25): that “In their 2018 book, How Democracies Die, the political scientists Steven Levitsky and Daniel Ziblatt documented how this process has played out in many countries, from Vladimir Putin’s Russia, to Recep Erdogan’s Turkey, to Viktor Orban’s Hungary. Add to these India’s Narendra Modi, China’s Xi Jinping, and the United States’ Donald Trump, among others. Bit by bit, the guardrails of democracy have been torn down, as institutions meant to serve the public became tools of ruling parties and self-serving ideologies, weaponized to punish and intimidate opposition parties’ opponents. On paper, these countries are still democracies; in practice, they have become one-party regimes….And it’s happening here [the United States] as we speak. If you are not worried about the future of American democracy, you aren’t paying attention” (Krugmam, 2019, A-25). We are reminded continuously that the late Carl Sagan, one of our most insightful scientific public intellectuals, had an interesting theory about highly developed civilizations. Given the number of stars and planets that must exist in the vast reaches of the universe, he said, there must be other highly developed and organized forms of life. Distance may keep us from making physical contact, but Sagan said that another reason we may never be on speaking terms with another intelligent race is (judging from our own example) could be their penchant for destroying themselves in relatively short order after reaching technological complexity. This book’s chapters, introduction, and conclusion examine the worldwide rise of partisan nationalism and the damage it has wrought on the worldwide pursuit of solutions for issues requiring worldwide scope, such scientific co-operation public health and others, mixing analysis of both. We use both historical description and analysis. This analysis concludes with a description of why we must avoid the isolating nature of nationalism that isolates people and encourages separation if we are to deal with issues of world-wide concern, and to maintain a sustainable, survivable Earth, placing the dominant political movement of our time against the Earth’s existential crises. Our contributors, all experts in their fields, each have assumed responsibility for a country, or two if they are related. This work entwines themes of worldwide concern with the political growth of nationalism because leaders with such a worldview are disinclined to co-operate internationally at a time when nations must find ways to solve common problems, such as the climate crisis. Inability to cooperate at this stage may doom everyone, eventually, to an overheated, stormy future plagued by droughts and deluges portending shortages of food and other essential commodities, meanwhile destroying large coastal urban areas because of rising sea levels. Future historians may look back at our time and wonder why as well as how our world succumbed to isolating nationalism at a time when time was so short for cooperative intervention which is crucial for survival of a sustainable earth. Pride in language and culture is salubrious to individuals’ sense of history and identity. Excess nationalism that prevents international co-operation on harmful worldwide maladies is quite another. As Pope Francis has pointed out: For all of our connectivity due to expansion of social media, ability to communicate can breed contempt as well as mutual trust. “For all our hyper-connectivity,” said Francis, “We witnessed a fragmentation that made it more difficult to resolve problems that affect us all” (Horowitz, 2020, A-12). The pope’s encyclical, titled “Brothers All,” also said: “The forces of myopic, extremist, resentful, and aggressive nationalism are on the rise.” The pope’s document also advocates support for migrants, as well as resistance to nationalist and tribal populism. Francis broadened his critique to the role of market capitalism, as well as nationalism has failed the peoples of the world when they need co-operation and solidarity in the face of the world-wide corona virus pandemic. Humankind needs to unite into “a new sense of the human family [Fratelli Tutti, “Brothers All”], that rejects war at all costs” (Pope, 2020, 6-A). Our journey takes us first to Russia, with the able eye and honed expertise of Richard D. Anderson, Jr. who teaches as UCLA and publishes on the subject of his chapter: “Putin, Russian identity, and Russia’s conduct at home and abroad.” Readers should find Dr. Anderson’s analysis fascinating because Vladimir Putin, the singular leader of Russian foreign and domestic policy these days (and perhaps for the rest of his life, given how malleable Russia’s Constitution has become) may be a short man physically, but has high ambitions. One of these involves restoring the old Russian (and Soviet) empire, which would involve re-subjugating a number of nations that broke off as the old order dissolved about 30 years ago. President (shall we say czar?) Putin also has international ambitions, notably by destabilizing the United States, where election meddling has become a specialty. The sight of Putin and U.S. president Donald Trump, two very rich men (Putin $70-$200 billion; Trump $2.5 billion), nuzzling in friendship would probably set Thomas Jefferson and Vladimir Lenin spinning in their graves. The road of history can take some unanticipated twists and turns. Consider Poland, from which we have an expert native analysis in chapter 2, Bartosz Hlebowicz, who is a Polish anthropologist and journalist. His piece is titled “Lawless and Unjust: How to Quickly Make Your Own Country a Puppet State Run by a Group of Hoodlums – the Hopeless Case of Poland (2015–2020).” When I visited Poland to teach and lecture twice between 2006 and 2008, most people seemed to be walking on air induced by freedom to conduct their own affairs to an unusual degree for a state usually squeezed between nationalists in Germany and Russia. What did the Poles then do in a couple of decades? Read Hlebowicz’ chapter and decide. It certainly isn’t soft-bellied liberalism. In Chapter 3, with Bruce E. Johansen, we visit China’s western provinces, the lands of Tibet as well as the Uighurs and other Muslims in the Xinjiang region, who would most assuredly resent being characterized as being possessed by the Chinese of the Han to the east. As a student of Native American history, I had never before thought of the Tibetans and Uighurs as Native peoples struggling against the Independence-minded peoples of a land that is called an adjunct of China on most of our maps. The random act of sitting next to a young woman on an Air India flight out of Hyderabad, bound for New Delhi taught me that the Tibetans had something to share with the Lakota, the Iroquois, and hundreds of other Native American states and nations in North America. Active resistance to Chinese rule lasted into the mid-nineteenth century, and continues today in a subversive manner, even in song, as I learned in 2018 when I acted as a foreign adjudicator on a Ph.D. dissertation by a Tibetan student at the University of Madras (in what is now in a city called Chennai), in southwestern India on resistance in song during Tibet’s recent history. Tibet is one of very few places on Earth where a young dissident can get shot to death for singing a song that troubles China’s Quest for Lebensraum. The situation in Xinjiang region, where close to a million Muslims have been interned in “reeducation” camps surrounded with brick walls and barbed wire. They sing, too. Come with us and hear the music. Back to Europe now, in Chapter 4, to Portugal and Spain, we find a break in the general pattern of nationalism. Portugal has been more progressive governmentally than most. Spain varies from a liberal majority to military coups, a pattern which has been exported to Latin America. A situation such as this can make use of the term “populism” problematic, because general usage in our time usually ties the word into a right-wing connotative straightjacket. “Populism” can be used to describe progressive (left-wing) insurgencies as well. José Pinto, who is native to Portugal and also researches and writes in Spanish as well as English, in “Populism in Portugal and Spain: a Real Neighbourhood?” provides insight into these historical paradoxes. Hungary shares some historical inclinations with Poland (above). Both emerged from Soviet dominance in an air of developing freedom and multicultural diversity after the Berlin Wall fell and the Soviet Union collapsed. Then, gradually at first, right wing-forces began to tighten up, stripping structures supporting popular freedom, from the courts, mass media, and other institutions. In Chapter 5, Bernard Tamas, in “From Youth Movement to Right-Liberal Wing Authoritarianism: The Rise of Fidesz and the Decline of Hungarian Democracy” puts the renewed growth of political and social repression into a context of worldwide nationalism. Tamas, an associate professor of political science at Valdosta State University, has been a postdoctoral fellow at Harvard University and a Fulbright scholar at the Central European University in Budapest, Hungary. His books include From Dissident to Party Politics: The Struggle for Democracy in Post-Communist Hungary (2007). Bear in mind that not everyone shares Orbán’s vision of what will make this nation great, again. On graffiti-covered walls in Budapest, Runes (traditional Hungarian script) has been found that read “Orbán is a motherfucker” (Mikanowski, 2019, 58). Also in Europe, in Chapter 6, Professor Ronan Le Coadic, of the University of Rennes, Rennes, France, in “Is There a Revival of French Nationalism?” Stating this title in the form of a question is quite appropriate because France’s nationalistic shift has built and ebbed several times during the last few decades. For a time after 2000, it came close to assuming the role of a substantial minority, only to ebb after that. In 2017, the candidate of the National Front reached the second round of the French presidential election. This was the second time this nationalist party reached the second round of the presidential election in the history of the Fifth Republic. In 2002, however, Jean-Marie Le Pen had only obtained 17.79% of the votes, while fifteen years later his daughter, Marine Le Pen, almost doubled her father's record, reaching 33.90% of the votes cast. Moreover, in the 2019 European elections, re-named Rassemblement National obtained the largest number of votes of all French political formations and can therefore boast of being "the leading party in France.” The brutality of oppressive nationalism may be expressed in personal relationships, such as child abuse. While Indonesia and Aotearoa [the Maoris’ name for New Zealand] hold very different ranks in the United Nations Human Development Programme assessments, where Indonesia is classified as a medium development country and Aotearoa New Zealand as a very high development country. In Chapter 7, “Domestic Violence Against Women in Indonesia and Aotearoa New Zealand: Making Sense of Differences and Similarities” co-authors, in Chapter 8, Mandy Morgan and Dr. Elli N. Hayati, from New Zealand and Indonesia respectively, found that despite their socio-economic differences, one in three women in each country experience physical or sexual intimate partner violence over their lifetime. In this chapter ther authors aim to deepen understandings of domestic violence through discussion of the socio-economic and demographic characteristics of theit countries to address domestic violence alongside studies of women’s attitudes to gender norms and experiences of intimate partner violence. One of the most surprising and upsetting scholarly journeys that a North American student may take involves Adolf Hitler’s comments on oppression of American Indians and Blacks as he imagined the construction of the Nazi state, a genesis of nationalism that is all but unknown in the United States of America, traced in this volume (Chapter 8) by co-editor Johansen. Beginning in Mein Kampf, during the 1920s, Hitler explicitly used the westward expansion of the United States across North America as a model and justification for Nazi conquest and anticipated colonization by Germans of what the Nazis called the “wild East” – the Slavic nations of Poland, the Baltic states, Ukraine, and Russia, most of which were under control of the Soviet Union. The Volga River (in Russia) was styled by Hitler as the Germans’ Mississippi, and covered wagons were readied for the German “manifest destiny” of imprisoning, eradicating, and replacing peoples the Nazis deemed inferior, all with direct references to events in North America during the previous century. At the same time, with no sense of contradiction, the Nazis partook of a long-standing German romanticism of Native Americans. One of Goebbels’ less propitious schemes was to confer honorary Aryan status on Native American tribes, in the hope that they would rise up against their oppressors. U.S. racial attitudes were “evidence [to the Nazis] that America was evolving in the right direction, despite its specious rhetoric about equality.” Ming Xie, originally from Beijing, in the People’s Republic of China, in Chapter 9, “News Coverage and Public Perceptions of the Social Credit System in China,” writes that The State Council of China in 2014 announced “that a nationwide social credit system would be established” in China. “Under this system, individuals, private companies, social organizations, and governmental agencies are assigned a score which will be calculated based on their trustworthiness and daily actions such as transaction history, professional conduct, obedience to law, corruption, tax evasion, and academic plagiarism.” The “nationalism” in this case is that of the state over the individual. China has 1.4 billion people; this system takes their measure for the purpose of state control. Once fully operational, control will be more subtle. People who are subject to it, through modern technology (most often smart phones) will prompt many people to self-censor. Orwell, modernized, might write: “Your smart phone is watching you.” Ming Xie holds two Ph.Ds, one in Public Administration from University of Nebraska at Omaha and another in Cultural Anthropology from the Chinese Academy of Social Sciences, Beijing, where she also worked for more than 10 years at a national think tank in the same institution. While there she summarized news from non-Chinese sources for senior members of the Chinese Communist Party. Ming is presently an assistant professor at the Department of Political Science and Criminal Justice, West Texas A&M University. In Chapter 10, analyzing native peoples and nationhood, Barbara Alice Mann, Professor of Honours at the University of Toledo, in “Divide, et Impera: The Self-Genocide Game” details ways in which European-American invaders deprive the conquered of their sense of nationhood as part of a subjugation system that amounts to genocide, rubbing out their languages and cultures -- and ultimately forcing the native peoples to assimilate on their own, for survival in a culture that is foreign to them. Mann is one of Native American Studies’ most acute critics of conquests’ contradictions, and an author who retrieves Native history with a powerful sense of voice and purpose, having authored roughly a dozen books and numerous book chapters, among many other works, who has traveled around the world lecturing and publishing on many subjects. Nalanda Roy and S. Mae Pedron in Chapter 11, “Understanding the Face of Humanity: The Rohingya Genocide.” describe one of the largest forced migrations in the history of the human race, the removal of 700,000 to 800,000 Muslims from Buddhist Myanmar to Bangladesh, which itself is already one of the most crowded and impoverished nations on Earth. With about 150 million people packed into an area the size of Nebraska and Iowa (population less than a tenth that of Bangladesh, a country that is losing land steadily to rising sea levels and erosion of the Ganges river delta. The Rohingyas’ refugee camp has been squeezed onto a gigantic, eroding, muddy slope that contains nearly no vegetation. However, Bangladesh is majority Muslim, so while the Rohingya may starve, they won’t be shot to death by marauding armies. Both authors of this exquisite (and excruciating) account teach at Georgia Southern University in Savannah, Georgia, Roy as an associate professor of International Studies and Asian politics, and Pedron as a graduate student; Roy originally hails from very eastern India, close to both Myanmar and Bangladesh, so he has special insight into the context of one of the most brutal genocides of our time, or any other. This is our case describing the problems that nationalism has and will pose for the sustainability of the Earth as our little blue-and-green orb becomes more crowded over time. The old ways, in which national arguments often end in devastating wars, are obsolete, given that the Earth and all the people, plants, and other animals that it sustains are faced with the existential threat of a climate crisis that within two centuries, more or less, will flood large parts of coastal cities, and endanger many species of plants and animals. To survive, we must listen to the Earth, and observe her travails, because they are increasingly our own.

This chapter deals primarily with the experience of German Jewish conservatives and nationalists in the military during the First World War. It looks at Jewish soldiers as active participants in the German military, rather than as objects of the military’s actions. It focuses on frontline soldiers and the particular and peculiar position of military rabbis on the German Eastern Front. It proposes that the war, not least in the East, held great promise for German Jews. The chapter’s main argument is that, particularly in the East, Jewish Soldiers viewed themselves as active participants and contributors to the war until the very end. It thus adds to the growing focus on the way German Jews shaped the German war effort, notwithstanding the increasing antisemitism they experienced.

This chapter explores how the stadium became central to a mode of political spectacle in France, from the mid-1920s up through the end of the Second World War, at a moment when it was also critical to politics elsewhere in Europe. A range of political luminaries and groups, from the anti-fascist Popular Front coalition to the Vichy regime, promoted stadium-based spectacles as a visible manifestation of political vitality, mass support and masculine citizenship. The stadium gave politicians a vast spectator space that proved ideal for staging political rallies, political plays or religious ceremonies that both aspired to transform spectators into active participants and that entailed efforts to discipline the public. But while the crowd may have been disciplined and mobilized inside the stadium, it also eluded those constraints and often disappointed those politicians seeking to create a unified public. In the years after the Second World War, the French stadium gradually disappeared as a pre-eminent staging-ground for mass politics, as the stadium crowd itself became progressively depoliticized.

Traditionally, learning material is delivered in a textual format and on paper. For example, a learning module on a topic may include a description (or a tutorial) of the topic, a few examples illustrating the topic, and one or more exercise problems to gauge how well the students have achieved the expected understanding of the topic. The delivery mechanism of the learning material has traditionally been via textbooks and/or instructions provided by a teacher. A teacher, for example, may provide a few pages of notes about a topic, explain the topic for a few minutes, discuss a couple of examples, and then give some exercise problems as homework. During the delivery, students ask questions and the teacher attempts to answer the questions accordingly. Thus, the delivery is interactive: the teacher learns how well the students have mastered the topic, and the students clarify their understanding of the topic. In a traditional classroom of a relatively small size, this scenario is feasible. However, when e-learning approaches are involved, or in the case of a large class size, the traditional delivery mechanism is often not feasible. In this article, we describe an interface that is “active” (instead of passive) that delivers learning material based on the usage history of the learning material (such as degree of difficulty, the average score, and the number of times viewed), the student’s static background profile (such as GPA, majors, interests, and courses taken), and the student’s dynamic activity profile (based on their interactions with the agent). This interface is supported by an intelligent agent (Wooldridge & Jennings, 1995). An agent in this article refers to a software module that is able to sense its environment, receive stimuli from the environment, make autonomous decisions, and actuate the decisions, which in turn change the environment. An intelligent agent in this article refers to an agent that is capable of flexible behaviour: responding to events timely, exhibiting goal-directed behaviour, and performing machine learning. The agent uses the profiles to decide, through case-based reasoning (CBR) (Kolodner, 1993), which learning modules (examples and problems) to present to the students. Our CBR treats the input situation as a problem, and the solution is basically the specification of an appropriate example or problem. Our agent also uses the usage history of each learning material to adjust the appropriateness of the examples and problems in a particular situation. We call our agent Intelligent Learning Material Delivery Agent (ILMDA). We have built an end-to-end ILMDA infrastructure, with an active GUI front-end—that monitors and tracks every interaction step of the user with the interface, an agent powered by CBR and capable of learning, and a multi-database backend. In the following, we first discuss some related work in the area of intelligent tutoring systems. Then, we present our ILMDA project, its goals and framework. Subsequently, we describe the CBR methodology and design. Finally, we point out some future trends before concluding.