This edited volume offers a state of the art overview of fast and robust solvers for the Helmholtz equation. The book consists of three parts: new developments and analysis in Helmholtz solvers, practical methods and implementations of Helmholtz solvers, and industrial applications. The Helmholtz equation appears in a wide range of science and engineering disciplines in which wave propagation is modeled. Examples are: seismic inversion, ultrasone medical imaging, sonar detection of submarines, waves in harbours and many more. The partial differential equation looks simple but is hard to solve. In order to approximate the solution of the problem numerical methods are needed. First a discretization is done. Various methods can be used: (high order) Finite Difference Method, Finite Element Method, Discontinuous Galerkin Method and Boundary Element Method. The resulting linear system is large, where the size of the problem increases with increasing frequency. Due to higher frequencies the seismic images need to be more detailed and, therefore, lead to numerical problems of a larger scale. To solve these three dimensional problems fast and robust, iterative solvers are required. However for standard iterative methods the number of iterations to solve the system becomes too large. For these reason a number of new methods are developed to overcome this hurdle. The book is meant for researchers both from academia and industry and graduate students. A prerequisite is knowledge on partial differential equations and numerical linear algebra.

Sudanese Intellectuals in the Global Milieu: Capturing Cultural Capital propels Sudanese intellectuals into the global intellectual milieu and argues for their place in world intellectual history. The contributors posit that Sudan is currently in its most uncertain and perhaps most generative period, as the unrest, conflicts, and upheavals of the twentieth and twenty-first centuries threw Sudanese intellectuals and activists into identity, economic, environmental, religious, and existential crises. Despite these crises, the unrest has created a period of knowledge production and cultural production in Sudan. The contributors to the collection are Sudanese intellectuals who explore the history and evolution of knowledge production, thought, and cultural capital in Sudan.

Life in hell ain’t easy. Demons try to torture you for all eternity. Monsters want to eat you. There’s a stunning lack of reliable indoor plumbing. And it’s almost impossible to get ice cream. At least, until today, when three condemned teens and their annoying tagalong demon frenemy embark on a daring scheme to hijack a demon lord’s delivery truck. What happens next will take them on an epic journey across the underworld, an infernal excursion of nonstop excitement, danger and adventure. Presenting a devilishly fun new series from multiple Eisner-winning writer/letterer John Layman (CHEW, Suicide Squad: Kill Arkham Asylum) and Argentinian superstar artist Jok. Collects IN HELL WE FIGHT #1-#5, plus short stories from Image Anthology #10 and #11

Cixin Liu is one of the most important voices in world science fiction. A bestseller in China, his novel, The Three-Body Problem, was the first translated work of SF ever to win the Hugo Award. Liu's writing takes the reader to the edge of the universe and the end of time, to meet stranger fates than we could have ever imagined. With a melancholic and keen understanding of human nature, Liu's stories show humanity's attempts to reason, navigate and, above all, survive in a desolate cosmos. Praise for Cixin Liu: 'Your next favourite sci-fi novel' Wired 'Immense' Barack Obama 'Unique' George R.R. Martin 'SF in the grand style' Guardian 'Mind-altering and immersive' Daily Mail 'A milestone in Chinese science-fiction' New York Times 'China's answer to Arthur C. Clarke' New Yorker Winner of the Hugo and Galaxy Awards for Best Novel

Sudan has been in the headlines for all the wrong reasons. After decades of civil war, rebel uprisings and power struggles, in 2011 it gave birth to the world's newest country - South Sudan. But it's not been an easy transition, and the secession that was meant to pave the path to peace, has plunged the region into further chaos. In this updated edition of his ground-breaking investigation, Jok Madut Jok delves deep into Sudan's culture and history, isolating the factors that continue to cause its fractured national identity. With moving first-hand testimonies, Jok provides a decisive critique of a region in turmoil, and addresses what must be done to break the tragic cycle of racism, poverty and brutality that grips Sudan and South Sudan.

This study addresses the contemporary conflict of national identity in Sudan between the adherents of Islamic nationalism and those of customary secularism. The former urge the adoption of a national constitution that derives its civil and criminal laws from the Sharia, and want Arabic as the language of instruction in national institutions. The latter demand the adoption of secular laws, derived from the set of customary laws, and equal opportunities for all African languages beside Arabic and English. In the past, the adherents of Islamic nationalism imposed the Islamic-Arab model. In reaction, secularists resorted to violence; the Islamists declared Jihad against the secularists and adopted a racial war, which has caused a humanitarian disaster. The main primary material of this research is based on a survey conducted among 500 students of five universities in Sudan. Besides, the study considers the diverse theoretical models for the formation of a nation-state, where diversity is not discouraged, but states apply laws to promote religious and ethnic diversities within one territorial state.

Slavery has been endemic in Sudan for thousands of years. Today the Sudanese slave trade persists as a complex network of buyers, sellers, and middlemen that operates most actively when times are favorable to the practice. As Jok Madut Jok argues, the present day is one such time, as the Sudanese civil war that resumed in 1983 rages on between the Arab north and the black south. Permitted and even encouraged by the Arab-dominated Khartoum government, the state military has captured countless women and children from the south and sold them into slavery in the north to become concubines, domestic servants, farm laborers, or even soldiers trained to fight against their own people. Also instigated by the Khartoum government, Arab herding groups routinely take and sell the Nilotic peoples of Dinka and Nuer. Jok emphasizes that the contemporary practice of slavery in Sudan is not the result of two decades of civil war, as conventional wisdom in the media would have one believe. Instead he revisits the historic hostilities between the Islamic world to the north and, to the south, the Black African peoples, many of whom are Christian converts. For Arab traders "the nation of the blacks," or Bilad Al-Sudan, has traditionally been the source of slaves. When the slave trade developed into corporate enterprise in the nineteenth century, the slave-takers articulated distinctions based on race, ethnicity, and religion that marked the black, infidel southerners as indisputably inferior and therefore "natural" slaves. Such distinctions have survived for decades and have fueled various forms of oppression of the black south, even during those periods when slavery has not been authorized by the government. When it is authorized, as it is today, slavery then becomes the extreme form of this systemic oppression. War and Slavery in Sudan exposes the enslavement of black peoples in Sudan which has been exacerbated, if not caused, by the circumstance of war. As a black southerner and a member of the Dinka, a group targeted by Arab slave traders, Jok brings an insider's perspective to this highly volatile subject matter. He describes the various methods of capture, explores the heinous experience of captivity, and examines the efforts of slaves to escape. Jok also assesses the efforts of Dinka communities to locate and redeem, or buy back, slaves through middlemen, a strategy that has been supported by Western antislavery groups and church-based humanitarian agencies but has also been the subject of great moral debate. Throughout the book, Jok stresses that the search for settlement of the north-south conflict must be made in conjunction with a campaign to end slavery. He challenges the international community to move beyond diplomatic measures to take more coordinated action against the slave trade and bring liberation to the people of Sudan.

This edited volume offers a state of the art overview of fast and robust solvers for the Helmholtz equation. The book consists of three parts: new developments and analysis in Helmholtz solvers, practical methods and implementations of Helmholtz solvers, and industrial applications. The Helmholtz equation appears in a wide range of science and engineering disciplines in which wave propagation is modeled. Examples are: seismic inversion, ultrasone medical imaging, sonar detection of submarines, waves in harbours and many more. The partial differential equation looks simple but is hard to solve. In order to approximate the solution of the problem numerical methods are needed. First a discretization is done. Various methods can be used: (high order) Finite Difference Method, Finite Element Method, Discontinuous Galerkin Method and Boundary Element Method. The resulting linear system is large, where the size of the problem increases with increasing frequency. Due to higher frequencies the seismic images need to be more detailed and, therefore, lead to numerical problems of a larger scale. To solve these three dimensional problems fast and robust, iterative solvers are required. However for standard iterative methods the number of iterations to solve the system becomes too large. For these reason a number of new methods are developed to overcome this hurdle. The book is meant for researchers both from academia and industry and graduate students. A prerequisite is knowledge on partial differential equations and numerical linear algebra.

After decades of civil war, the people of southern Sudan voted to secede from the north in an attempt to escape the seemingly endless violence. On declaring independence, South Sudan was one of the least developed places on earth, but with the ability to draw upon significant oil reserves worth $150 million a month, the foundation for a successful future was firmly in place. How, then, did the state of the new nation deteriorate even further, to the point that a new civil war broke out two years later? Today, with both Sudans still hostage to the aspirations of their military and political leaders, how can their people escape the violence that has dominated the two countries' recent history? By giving voice to those who, after the break-up of Sudan, have had to find ways to live, trade and communicate with one another, Jok Madut Jok provides a moving insight into a crisis that has only rarely made it into our headlines. Breaking Sudan is a meticulous account, analyzing why violence became so deeply entrenched in Sudanese society and exploring what can be done to find peace in two countries ravaged by war.

Sudan is a country in turmoil, ravaged by civil war, plagued by roaming gangs of rebel and government militia, and is rarely out of the news. Despite government propaganda, tales of state-sponsored murder, genocide and humanitarian crises are rife, and there is a real need for a measured investigation which carefully examines the causes of the troubles.In this important book, Jok Madut Jok delves deep into Sudan's culture and past, isolating the factors that cause its fractured national identity. Highlighting the Arabization of the central government in the north and the imposition of this cultural identity upon Darfur and the Christian South, Jok analyses the vicious cycle of violence and goes on to ask what can be done to improve the plight of the Sudanese people in the future.