bluuebunny/crossref_metadata_2025 huggingface dataset:
La Naguala in Theory and Practice
Authors: Zaytoun Kelli D.
Published: January 2023

Chapter 1, “La Naguala in Theory and Practice,” traces Anzaldúa’s use of la naguala, the shapeshifter, in her published and unpublished works and explains how her thinking about the concept changed and became more important to her writing over time. La naguala is then put in conversation with Latina/x feminist phenomenology, posthumanism, new materialisms, Indigenous studies, and Nahua philosophy to locate the concept’s transdisciplinary utility. Zaytoun argues that Anzaldúa’s theory of la naguala exercises an understanding of subjectivity that participates in the Nahua concept of “teotl,” a self-generating energy, which is neither material nor spiritual but its own process of which everything is a part. The chapter closes with an analysis of la naguala’s position in Anzaldúa’s theory of personal and social transformation called conocimiento.
“An Artist in the Sense of a Shaman”
Authors: Zaytoun Kelli D.
Published: January 2023

Chapter 2, “‘An Artist in the Sense of a Shaman’: Border Arte as Decolonial Practice,” considers critiques of Anzaldúa’s use of Indigenous mythology and her and other scholars’ responses to them and proposes that Anzaldúa is not romanticizing an Indigenous past but, instead, is engaging in a practice of what she calls “border arte,” original creative expression formed in the moment of the artistic endeavor. Border artists consciously draw from their awareness of being in colonized spaces and work not to preserve a past but to create new assemblages informed by one’s ancestry and the artist’s particular cultural moment. The chapter also traces Anzaldúa’s earliest thinking about la naguala in Borderlands / La Frontera and identifies a shamanic, shapeshifting pattern in this text and her others.
Connections with Arab American Feminism
Authors: Zaytoun Kelli D.
Published: January 2023

In the spirit of Anzaldúa’s commitment to working across differences to end oppressions, chapter 3, “Connections with Arab American Feminism.” brings Anzaldúa’s work together with diasporic Arab women writers, who are often overlooked in feminist conversations about women of colors. Highlighted in this chapter are the creative works of Diana Abu-Jaber, Joanna [Joe] Kadi, Mohja Kahf, Therese Saliba, and Evelyn Shakir and critical discussions of Arab American feminist scholars. The chapter also explores Arab feminist writings in relationship to AnaLouise Keating’s three lessons for the development of postoppositional consciousness. Arab American feminist writers are linked with Anzaldúa, in part, to explore the metaphysical aspects of shapeshifting selfhood, in general, while recognizing the specific realities of a culturally based group in the United States.
Coaching Duke
Authors: Moser Patrick
Published: January 2023

The Los Angeles Athletic Club hired Freeth as their head swimming instructor in October 1913, and he worked in downtown L.A. for about fifteen months. He recruited Duke Kahanamoku and helped him improve on his starts and turns, lowering Duke’s times in the short-distance races. Duke surfed at Corona del Mar in September 1914, and Freeth surfed at the opening of the Huntington Beach Pier several months before, thus spreading beach culture into Orange County. After Duke traveled to Australia and New Zealand on a swimming tour in late 1915, then decided to quit the Los Angeles Athletic Club, Freeth resigned his position. He dropped off the radar until the summer of 1916, when he was hired by the San Diego Rowing Club.
Last Breath
Authors: Moser Patrick
Published: January 2023

Freeth contracted the influenza virus in January 1919 and was admitted to Agnew Hospital in downtown San Diego. The San Diego Rowing Club used the local press to raise money to pay for his medical bills. After nearly three months in the hospital, Freeth caught pneumonia and died on April 7, 1919. He was thirty-five years old. His ashes were sent to Honolulu, and Charles E. Sumner, past president of the San Diego Rowing Club, gave the eulogy at his funeral. Freeth’s obituary noted his influence on what would be called the waterman tradition, to which can be added a waterwoman tradition as well. His primary legacy is the development of surfing and lifeguarding, which combined to form the foundation of California beach culture.
Fighting the Open Shop
Authors: Castillo Thomas A.
Published: January 2023

Workers resisted precarity by attempting to make Miami a union town. Unionization efforts largely succeeded in the construction sector and other skilled trades. This organizing expanded during WWI to include such areas as street-car operation and retail work. Black workers also tried to organize even while facing exclusion in skilled work such as carpentry. Despite these flaws, unionization represented expressions for moral economic ends—that is, recognition of the dignity of the worker through a living wage and decent working conditions. Workers articulated a vision of moral economy in their fight against the high cost of living and drive for greater security. The chapter outlines the struggle against employer efforts to implement and maintain an open-shop city through the 1920s.
Winter Playground Blues
Authors: Castillo Thomas A.
Published: January 2023

Three key interrelated issues shaped the politics and economics of south Florida unemployment through the 1930s: regular seasonal unemployment, home labor protectionism, and a set of deficient welfare programs reliant on state exclusionary practices. These three issues defined the contours of unemployment as a problem and the limitations the unemployment movement faced in their fight against poverty and joblessness. Tracing the history of Miami’s Depression-era unemployment, the chapter explores how class harmony discourse, expressed in home labor terms, mitigated class tension by reinforcing local efforts to exclude impoverished transients and migrants from the city. It provides a history of the hobo express, a local tradition whereby the police forcibly expelled the transient poor in order to protect the tourist tropical landscape and home labor.
Starving Beauties?
Authors: Okabe Tsugumi (Mimi)
Published: January 2023

This chapter examines one of Japan’s best-selling and trending diet products among women in Japan: Ojôsama Kôso Jewel (Princess Enzyme Solution Jewel), created by Rivaland Co. to gain an understanding of how social photography on Instagram reinforces idealized perceptions of beauty, body image, and thinness among Japanese women at the risk of dangerous dieting. The study analyzed images and captions from Rivaland’s Instagram account (rivaland_ojyosamakouso) in order to uncover patterns of representation and to explore the limitations and potentials of the commodification of female agency, as well as standards of beauty and femininity through meal replacements.
Picturing Digital Tastes
Authors: Truman Emily
Published: January 2023

Unicorn foods are a unique social media food trend in North American popular culture, and the specific example of the unicorn latte is informative for thinking through shifting expectations around appearance and taste when it comes to digital images of food. This chapter explores a trademark infringement case related to the drink’s commercialization as a starting point to engage with its cultural origins and popular representation. This exploration of the intersection between mobile photography, food marketing tactics, and consumption habits highlights the digital visibility of the unicorn latte, and offers insights into the changing social media landscape of food.
FreakShakes and Mama Noi
Authors: Kirkwood Katherine
Published: January 2023

Instagram’s emergence has created tensions between amateurs and professionals in food and food media industries. Using two Australian case studies, this chapter analyzes key aspects of Instagram’s influence on food media and culture. Canberra café Pâtissez’s FreakShake creation brought immense success, but Instagrammable food porn has consequences for chefs, businesses, health, and waste. Meanwhile former MasterChef Australia contestant Marion Grasby’s use of IGTV to promote her line of sauces highlights Instagram’s blurring of boundaries between amateur and professional, and what constitutes a cooking show. These cases document how Instagram has instigated renegotiations of power and food conventions.
Transgressive Food Practices on Instagram
Authors: Leer Jonatan , Krogager Stinne Gunder Strøm
Published: January 2023

Highly aestheticized pictures of food circulate on Instagram often with a focus on elegance and composition, particularly as restaurants compete to make their food and interiors Instagrammable. Recently, a counter-tendency has appeared in which restaurants attempt to brand themselves through different aesthetics and discourses. This chapter analyzes the Instagram profile of chef and restauranteur Umut Sakarya, the owner of Guldkroen (the Golden Inn). His account presents food in a grotesque, humorous, and often provocative manner and it is argued—based on a theoretical Bourdieusian perspective—that using Instagram in this manner functions to brand the chef and restaurant as rebellious.
Farming, Unedited
Authors: Andersen Joceline
Published: January 2023

Public farmer Instagram accounts give consumers a sense of direct participation in an ecosystem networked around food and the environment. While these bucolic images describe farm life for a public audience, there are also private places on Instagram where farmers can share. A group of small-scale organic farmers in the Pacific Northwest have engaged with the affordances of Instagram to create a closed local network, the farmer “darkgram.” Farmers seek out local advice on the network, using these private spaces to move beyond an economic impetus to present beautiful images to consumers, working instead to strengthen sustainable farming practices.
Subscribing to the Sunday Newspaper
Authors: Moore Paul , Gabriele Sandra
Published: January 2023

There was no singular type of Sunday paper. A multiplicity of Sunday supplements produced new kinds of readers through their very form and design. Each asked readers to do more than read, but to interact with the materiality of the paper as a form of leisure. Sunday supplements established a different temporality from the weekday newspaper and the bustle of the workweek. They entreated readers to spend time with the paper, tying them to the rhythms of the weekend and the home. This temporality linked one Sunday to another, making a subscription all the more logical by providing a cultural aesthetic for the home. Most varieties of supplements appealed to women readers, who were considered especially important for securing home delivery. Lithographed art and photographic supplements, sheet music, novels and fiction magazines, fashion plates, and sewing patterns: all offered a distinctly feminine appeal. Games, puzzles, coloring books and all variety of paper toys appealed to children. Women readers found aesthetic appreciation; juvenile readers delighted in aesthetic play. Even in later days of early radio, Sunday papers were conduits of popular education explicitly including all members of the family as reading subjects, each invested in subscribing to the paper.
The Corporeal Character of Circulation
Authors: Moore Paul , Gabriele Sandra
Published: January 2023

Syndication provided currency and connectivity on a mass scale, overcoming the limitations of print circulation. In the 1880s, newspaper syndicates began to offer an affordable means for smaller newspapers to include new stories by popular writers in their Sunday editions. Syndicated humorists, Bill Nye and M. Quad, were among the most popular features, later joined by syndicated cartoons from The Comic Sketch Club. Many Sunday papers in cities across the country began printing entire pages of humor and comics, then entire comic supplements. To compete, metropolitan Sunday papers introduced color and illustrated supplements, at first serving multiple purposes—decorative, humorous, and satirical at once. Color sections opened a special opportunity for cartoonists. Newspapers had often used recurring comic characters as mascots to personify the popularity of the paper. But the incredible popularity of The Yellow Kid, so central to the rivalry of “yellow journalism” between Hearst and Pulitzer, led other cartoonists to create recurring children's characters, giving rise to the serial comic strip. Color comic syndication began late in 1900, first with Hearst's famous cartoon characters. With syndication, even small–city papers without their own color press could include the new century's newest popular media sensation: the funny pages.
Between Poverty and Segregation
Authors: Fernández Lilia
Published: January 2023

The 1980s were an era of severe social inequalities for Latino/a and African American children in urban America. The disinvestment, deindustrialization, and decline of cities like Chicago coupled with the racial antipathy of whites toward “nonwhite” groups resulted in starkly segregated neighborhoods and schools. Yet when researchers examine disparities in Latino/a educational achievement, they seldom take these structural conditions into account. This chapter shows that many Latino/a children who attended Chicago Public Schools in the 1980s and 1990s were living in poverty and segregated conditions, factors that should be considered when assessing Latino/a educational achievement.
Mexican-Origin Boys Negotiating Social and Academic Identity in a Racialized School Context
Authors: Sosa Leticia Villarreal
Published: January 2023

This chapter highlights the experiences of sixteen Mexican-origin boys as they transitioned to high school in a community characterized by high rates of gang violence. Drawing a longitudinal study of the transition to high school, this chapter uses the extended case method (ECM) grounded in a Chicana feminist epistemology. Using borderlands and social identity as the theoretical framework, results suggest that the school response to the youth gang problem contributed to students’ experiences of racialization and impacted their educational trajectories. The importance of teacher relationships and family and cultural supports provides a starting point for solutions that can help students develop positive academic identities consistent with their perceptions of themselves as Mexican-origin students.
“A Shot of Rhythm and Blues”
Authors: Reali Christopher M.
Published: January 2023

This chapter analyzes the term “Muscle Shoals sound,” a phrase that first appeared publicly in May 1969. Two competing recording studios, FAME and Muscle Shoals Sound, proclaimed ownership over the “Muscle Shoals sound” in ads placed in Billboard and other sources. Other Shoals-based recording studios also adopted the catchphrase. The press often used the term to indicate a recording process, a musical brand, and also a particular “sound,” albeit one that is never clearly defined. The vast majority of tracks associated with the so-called Muscle Shoals sound were recorded by Black vocalists. This chapter unpacks the Muscle Shoals sound by applying the theory of the sonic color line and Eidsheim's notion of “sonic blackness,” along with ideas taken from marketing.
Introduction
Authors: Thaggert Miriam
Published: January 2023

The introduction details the significance of mobility for the African American subject and the dilemmas travel, and especially train travel, posed to African American women. Tracing earlier cultural studies of the train – Leo Marx’s The Machine in the Garden and Wolfgang Schivelbusch’s The Railway Journey – the chapter notes how those studies lack a discussion of Black women and Black laborers. Riding Jane Crow examines four specific forms or instances of Black female railroad travel—early Black female intellectuals who described Black female travel as passengers, Black middle-class women who sued to ride in first-class “ladies’ cars,” Black women railroad station food vendors, and Black maids on Pullman trains—to see one of the most important forms of public transportation through the eyes of African American women. Using the experience of fugitive Ellen Craft as an example, the introduction defines terms such as performative train riding, situational riding, and precarity of proximity. The introduction ends with a brief discussion of W. E. B. Du Bois, progress, and Black femininity in The Souls of Black Folk.
Introduction
Authors: Delgadillo Theresa , Rivera-Servera Ramón H. , Cadava Geraldo L. , Fox Claire F.
Published: January 2023

This opening essay asserts that we create place through performative, activist, and aesthetic imaginaries as well as representational practices that render a diversity of Latinx Midwests through the formal creative practices of writing, photography, film, theatre, performance, and dance, as well as the informal creative practices of craft and community-making in social gathering. Drawing on the work of Priscilla Solis Ybarra, Julie Sze, and Elizabeth Povinelli, among other scholars, this chapter outlines the power of cultural expression as endurance in placemaking, illustrating the interconnection among sustenance, sustainability, temporality, and scale in Latinx cultural expressions by considering the volume’s research against the backdrop of recent public discourse about Latinxs in the U.S. In considering both social and environmental climate, the co-editors suggest, this volume prompts us to consider for whom are we imagining healthier worlds.
Radical Hospitality in a Small Iowa Town
Authors: Fox Claire F.
Published: January 2023

How do Latinx people make places for themselves and recognize their long-standing presence in small-town and rural Midwestern settings? This chapter focuses on a range of placemaking practices from performance to storytelling and community celebrations that occur in Hampton, Iowa (est. population 4231), a town with an established and growing Latinx population. It explores the potential for cultural events to model radical hospitality--unconditional welcome with the potential for reciprocity--as a political, ethical, and community-based practice through which Latinx Midwesterners express their attachment to place and imagine collective futures. The chapter further highlights the important role of Hampton’s Latinx-serving community center, La Luz Hispana (today Centro Cultural La Luz), as a facilitator of public events in which Latinx people gather and fluidly assume the roles of both guest and host.
Introduction
Authors: Engelman Ralph , Shenkman Carey
Published: January 2023

The introduction argues that the Espionage Act of 1917 is the most important yet least understood piece of legislation threatening the free flow of information in American history. To date no single volume has systematically traced the century-long life of the law. The book will not examine espionage as it is commonly understood, but the Espionage Act's increasingly widespread use to limit free speech, freedom of the press, and freedom of information in regard to US foreign and military policy. The book will be divided into three periods: “Targeting the Opposition: WWI and WWII”; “Criminalizing Leaks: The Cold War”; and “Policing Digital Journalism: The War on Terror.”
The Ambivalence of Francis Biddle
Authors: Engelman Ralph , Shenkman Carey
Published: January 2023

This chapter traces the evolution of the Espionage Act during World War II from the perspective of attorney general and civil libertarian Francis Biddle. Biddle struggles to stave off Hoover's efforts to use the act to intimidate the Black press, and Roosevelt's desire to deploy the law against a newspaper perceived as a political enemy. Hoover, who targeted Black publishers during World War I, insists again on using the act to criminalize protest against racism. Biddle is forced into painful negotiations with John Sengstacke, publisher of the Chicago Defender. FDR also targets his archnemesis, Robert McCormick, publisher of the Chicago Tribune, for the publication of a military secret. These efforts set the stage for the act's increased use in the future.
Maracatu Nação Cambinda Estrela
Authors: Enriquez Falina
Published: January 2023

This chapter shows how musicians in Recife, Brazil, are contesting cultural policies and neoliberal discourses that reinforce the marginalization of working-class, Black citizens. Maracatu Nação Cambinda Estrela, a musical and activist community organization, articulates a “minor cosmopolitan” scale-making project that integrates the locally unique, traditional genre of maracatu into Global Southern Afro-diasporic, antiracist, and leftist movements. Through their political stance, reluctance to commercialize their efforts, and prioritization of community members’ needs and desires, the group’s members resist the homogenizing institutional standards that instrumentalize multiculturalism and limit who can participate in state-sponsored events. Rather than serving as an aesthetic embellishment, music is key to how the group builds solidarity across social and geographic boundaries to envision a better, more just future.
Labor's Outcasts
Authors: Hazelton Andrew J.
Published: January 2023

This book argues that growers used political control over Bracero Program guestworker policies to defeat farmworker unionism in the United States. Taking a large geographic view, it recaptures the forgotten history of farmworker unionism between the New Deal and the Farmworker Movement years, while tracing major changes in agriculture and Mexican migration in North America. By following the efforts of the Southern Tenant Farmers Union and its successors, the National Farm Labor Union and the National Agricultural Workers Union, it illustrates that, although direct farmworker organizing failed in the face of growers’ economic and political power, reformers generated public interest in the “farmworker question” and eventually broke the power of congressional factions—the “farm bloc”—that supported guestworker policies. Union leaders H. L. Mitchell and Ernesto Galarza, the most vociferous critics of Bracero Program abuses, joined forces with reformers among civil rights activists, religious reformers, and liberals to lobby for farmworker improvements. Meanwhile, the national labor movements in both the United States and Mexico offered platitudes when it came to farmworker issues. Both movements were closely aligned with their nation’s foreign policies, and union members in both countries would have suffered labor competition if rising demographic pressure from the Green Revolution in the Mexican countryside had led to urban migration. Together, these factors combined in North America to cement farmworkers across the continent as the “stepchildren of labor.”
Border Fantasies
Authors: Hazelton Andrew J.
Published: January 2023

Cyclical undocumented migration dwarfed guestworker braceros. Mexican migration increased in the postwar era, complicating union organizers’ work. In Texas, Mexican American activists and unions publicized a “wetback problem.” Cold War politicians fretted over border security. Eisenhower responded with Operation Wetback, an immigration campaign to curtail growers’ hiring of undocumented workers. Meanwhile, NAWU tried to influence labor markets by working with Mexican unions in promising ways. National labor leaders lent support as part of Cold War hemispheric labor politics. Ultimately, the interests of the Mexican and US governments and their respective labor movements could not be meaningfully aligned.
Dying Union, Rising Movement, 1959–66
Authors: Hazelton Andrew J.
Published: January 2023

This chapter examines the AWOC and the Bracero Program’s final years. The AWOC struggled because of inexperienced leadership, Ernesto Galarza’s departure, and ongoing power struggles between George Meany and Walter Reuther in the AFL-CIO. The NAWU was destroyed, but the reform coalition it had mobilized won victories. Growers resisted, but advocates elevated farmworker issues to the national discussion. Farm bloc support for guestworkers splintered, and the historic Eighty-Eighth Congress voted to end the program in 1963. Simultaneously, a “farmworker moment” arrived. The National Farm Workers Association merged with the AWOC to create the United Farm Workers in 1966, indicating new civil rights–labor organizing potential.
Measuring the social impact on employee engagement using agent-based simulation
Authors: Rahman Arief , Gunani Partiwi Sri , Sari Dewi Ratna , Aranti Wessiani Naning
Published: January 2023

Employee Engagement is a pattern of human interaction in an organization that presents excitement, dedication, and comfort in the work environment: the higher employee engagement, the more efficient way to reach the goals. Measuring the impact of employee interaction on employee engagement became essential for the organization. This study applied the social impact model to describe the interaction patterns of employees within an organization, including the intervention of leaders in groups. The agent-based simulation is constructed to simulate the behavior and interaction patterns. This study assessed the impact of 4 employee engagement aspects: recognition, care, commitment, and best friend. Agent leader and agent employee were the two primary roles of the simulation. The employee engagement survey has conducted by our university with more than 380 respondents, including the leader and staff. New trait adoption role as a pattern of employee engagement interaction has been formulated in this study and becomes a state of change of agent behavior in simulations. The level of employee engagement can be calculated and displayed in the dynamics of change with agent-based simulations. The four aspects of employee engagement show the effect of increasing the level of engagement with a variety of different patterns
Las galeras de Tierra Firme (1578-1612) : Fiscalidad, comercio, abastecimiento y proyección del poder naval castellano en el Caribe Sur
Authors: Amaya Palacios Sebastián
Published: January 2023

Esta monografía busca trazar algunas líneas sobre el desarrollo del Estado Fiscal Militar (Fiscal-Military State) para el caso del Imperio español, y específicamente en la región Circuncaribe sur. Se aborda el olvidado siglo XVI, pretendiendo emular la temática, enfoque y metodología de algunos de sus textos pioneros. Para ello, se ha optado por privilegiar el análisis de las capacidades navales y, en especial, el proceso de estatalización de las armadas, tomando como estudio de caso la creación de la primera escuadra de galeras guardacostas en el Caribe en 1578. Esta escuadra, acantonada en el puerto de Cartagena de Indias, patrullaba desde el cabo de la Vela hasta Veragua. XIV Premio de Estudios Iberoamericanos La Rábida 2021 al mejor Trabajo Fin de Máster en la temática de Ciencias Sociales y Jurídicas y de Humanidades.
Study on Rockburst Tendency of Deep Underground Engineering based on Multi-Factor Influence
Authors: Zhu Zihui , Sun Feiyue , Guo Jiaqi
Published: January 2023

Rockburst disaster seriously threatens the construction schedule of underground tunnel engineering and the safety of construction workers. Rockburst prediction has become one of the critical methods for evaluation of surrounding rock stability and safe construction of deep underground engineering. To further understand the occurrence mechanism of rockburst disaster and predict rockburst in underground engineering more accurately, firstly, the typical rockburst tendency criterion and the critical factors affecting the rockburst development process are systematically summarized and analyzed, and the main control factors reflecting the whole process of rockburst development are screened and analyzed: mechanics, brittleness, integrity, and energy storage factor. Secondly, according to the comprehensive consideration of the main control factors, based on the energy conversion and overall failure mechanism in the process of rock failure, a new multi-parameter rockburst tendency criterion is proposed by comprehensively considering the stress states of rock unit under different stress paths. Finally, the rockburst criterion proposed in this paper is applied to typical engineering cases to verify its rationality and accuracy. Based on a rockburst section in the Sangzhuling tunnel, the possible location of rockburst is simulated based on the 3D discrete element numerical simulation platform, and the rockburst criterion proposed in this paper is further verified by actual engineering. The results show that: the rockburst criterion considering the mechanical factor(σθ/σc), brittleness factor(σc/σt), integrity factor (Kv) and energy storage factor (Ue/U0) can comprehensively and truly reflect the rockburst development process; based on the rockburst tendency criterion proposed in this paper, the occurrence of rockburst in typical engineering cases is calculated and verified, and the predicted results are in good agreement with the actual situation; the numerical simulation of the typical rockburst section prediction in the Sangzhuling tunnel shows that the distribution characteristics of rockburst tendency based on the criterion in this paper are consistent with the on-site rockburst occurrence, and there is a strong rockburst tendency on the right of the tunnel vault, which further verifies the effectiveness and engineering applicability of the criterion in the rockburst tendency prediction. The results of the research can provide some reference for predicting the tendency of rockburst in deep underground engineering.
O Efeito da Heterogeneidade no Desempenho de Sistemas Paralelos de Banco de Dados
Authors: Gomes Luiz Henrique , Almeida Virgílio , Laender Alberto Henrique Frade
Published: January 2023

A enorme capacidade computacional provida pelas arquiteturas paralelas juntamente com a facilidade de se paralelizar as operações sobre bancos de dados relacionais incentivaram o desenvolvimento de sistemas paralelos de banco de dados. Além disso, o uso de microprocessadores de alto desempenho e baixo custo para a construção de máquinas paralelas torna esses sistemas muito competitivos quando comparados aos mainframes, até então a principal plataforma para grandes aplicações de banco de dados. No entanto, os sistemas paralelos apresentam alguns problemas que inibem o aproveitamento real de sua grande capacidade de processamento. Entre eles, encontra-se o data skew que se refere à dificuldade de se dividir igualmente o processamento de uma consulta entre os processadores do sistema, devido a características inerentes aos dados. O objetivo deste artigo é apresentar uma proposta de arquitetura, denominada heterogênea, e analisar, através de simulação, o seu desempenho na presença do problema de data skew.
Implementação de dinâmica molecular em uma rede de transputers
Authors: Travieso Gonzalo , Slaets Jan F. W.
Published: January 2023

Apresentamos neste artigo uma implementação de simulação de dinâmica molecular de partículas de Lennard-Jones em um sistema de processamento paralelo constituído por uma rede de transputers. Mostramos que o tempo de processamento cresce de forma aproximadamente linear com o número de partículas, e decai também de forma aproximadamente linear com o número de processadores.
Um Sistema de Programação e Processamento para Sistemas Multiprocessadores
Authors: Sato Liria Matsumoto
Published: January 2023

A complexidade para utilizar com eficiência os recursos de paralelismo presentes em computadores multiprocessadores exige ambientes de programação adequados. É apresentado neste trabalho um ambiente de programação pam sistemas multiprocessadores que permite através de uma linguagem de programação paralela explorar múltiplos níveis de paralelismo.
A System for Data-Driven Programming of Multicomputers
Authors: Gaudiot Jean-Luc , Ventre Giorgio
Published: January 2023

Distributed systems are a promising solution to increase the computational power and fault-tolerance capabilities currently available in traditional computer architectures. While it is technologically possible to integrate large numbers of processors to form a single parallel machine, new approaches to the programming of such machines are needed. Indeed one of the major problems is to offer a programming model independent from the physical architecture and topology of parallel systems. The data-driven approach seems to be a good candidate for such a model, but requires an implementation able to bide the architectural complexity of a multicomputer. In this paper we show how we applied these principies to a Transputer-based parallel system and the characteristics of the resulting programming environment.
Tratamento de Código Seqüencial no Modelo de Fluxo de Dados
Authors: Visoli Marcos C. , Catto Arthur J.
Published: January 2023

Uma das questões ainda não resolvidas eficientemente em multiprocessamento é a determinação do tamanho ou granularidade ideal das tarefas ou processos, com o objetivo de obter desempenho aceitável. A dificuldade decorre do fato de que a granularidade conflita com o volume de sincronizações a serem realizadas. Máquinas multiprocessadoras baseadas no modelo von Neumann exploram paralelismo ao nível de subprograma e comandos e, conseqüentemente, suportam granularidade grossa. Isso implica em um número menor de sincronizações, mas também numa inadequada exploração do paralelismo das aplicações. Máquinas de fluxo de dados, por sua vez, exploram paralelismo ao nível de instrução, suportando, portanto, granularidade fina. Apesar de tratarem o paralelismo mais adequadamente do que as máquinas de von Neumann, as máquinas de fluxo de dados pecam pela necessidade de um grande número de sincronizações. Este artigo trata da redução do número de sincronizações no modelo de fluxo de dados a partir do agrupamento de código seqüencial.
On new Classes of Multistage Interconnection Networks
Authors: Melo Julio C. D. de , Jenevein Roy M.
Published: January 2023

In this work a new generalized model for Multistage lnterconnection Networks (MINs) is proposed, extending the classes of existing MINs, such as SW- and CC-banyans. By introducing a labelling scheme for nodes in the network, a connection formula is established that makes it possible to describe an enormous number of new subclasses, extending substantially the choice of alternative topologies. To give a flavor of the great variety and advantage of some subclasses, their average distance is computed for networks of given size.
Implementação Paralela do Filtro de Kalman para Aplicações em Tempo Real
Authors: Santos Walter Abrahão dos , Hemerly Elder Moreira
Published: January 2023

Neste trabalho apresenta-se o desenvolvimento e implementação paralela do filtro Kalman. O processamento numérico é efetuado em uma arquitetura MIMO baseada em processadores digitais de sinal de terceira geração com ponto flutuante, pipelining e arquitetura Harvard. Aspectos de partição do algoritmo, scheduling de processadores e deadlock são abordados. Um método heurístico para paralelização de algoritmos seriais é proposto. O speedup é obtido implementando-se, em tempo real, o filtro de Kalman nas versões serial e paralela, e aplicando-o para estimar os estados de um sistema dinâmico com ruído de medidas.
Um Sistema de Processamento Distribuído para Controle e Aquisição de Dados
Authors: Mendonça M. L. M. , Roitman M. , Almeida H. L. S.
Published: January 2023

O presente trabalho descreve um sistema de processamento distribuído de alto desempenho para controle e aquisição de dados, desenvolvido para automatizar a operação de um simulador analógico em tempo real de redes elétricas de alta tensão. O sistema consiste de seis unidades de aquisição e processamento de dados controladas por processadores digitais de sinal (DSP), e uma unidade central de processamento de 16 bits (CPU), responsável pela interface homem-máquina e pelo controle de relés e chaves eletrônicas que simulam chaveamentos na rede elétrica. A comunicação entre CPU e DSP's é efetuada através de memórias dual-port em esquema mestre-escravos. Uma versão preliminar do sistema está instalada no Laboratório de Simulação de Sistemas Elétricos do CEPEL e vem sendo utilizado em estudos para diversas empresas do setor elétrico brasileiro. A arquitetura apresentada também pode operar como um controlador digital de processos em malha fechada.
Algoritmos para Descobrir o Máximo em um Multicomputador Baseado em Barramentos Hierárquicos
Authors: Freitas Alex Alves , Kirner Claudio
Published: January 2023

Este artigo apresenta algoritmos para determinação do valor máximo dentre n valores distintos, em um multicomputador baseado em barramentos hierárquicos. É analisada a influência, no projeto e desempenho desses algoritmos, de características da arquitetura, como: número total de EPs (elementos de processamento), razão entre número de "clusters" e número de EPs por "cluster", e relacionamento entre tempo para transmissão de mensagens em um barramento e tempo para processamento em um EP.
Uma Avaliação do Impacto das Operações de E/S no Desempenho do Multiprocessador Multiplus
Authors: Oliveira Sidney de Castro , Aude Júlio Salek
Published: January 2023

Este trabalho apresenta um estudo sobre o impacto das operações de E/S no desempenho dos elementos processadores do Multiplus, um multiprocessador com memória global compartilhada em desenvolvimento no NCE/UFRJ. As questões sao avaliadas a partir de dados oriundos de simulações que procuraram retratar a operadonalidade do subsistema de E/S dentro do contexto do Multiplus.
Aspectos de implementação e desempenho de um sistema distribuído “LINDA”
Authors: Guedes Neto Dorgival O. , Carvalho Osvaldo S. F.
Published: January 2023

Um sistema distribuído para uma rede de estações de trabalho deve levar em consideração aspectos como facilidades de comunicação da rede, acesso a recursos do núcleo do sistema operacional de cada máquina, etc. Este trabalho apresenta as opções adotadas no desenvoluimento de um núcleo para processamento distribuído em uma rede de estações de trabalho no Departamento de Ciência da Computação da UFMG. São abordadas as opções de implementação possiveis, detalhes do protocolo de comunicação adotado e alguns resultados dos testes de desempenho do sistema já em operação.
Dimensionamento de processadores com arquitetura horizontal para exploração de micro e mesoparalelismo
Authors: Campos Geraldo Lino de
Published: January 2023

Arquiteturas horizontais são caracterizadas pela possibilidade de controlar independente e diretamente as diversas unidades funcionais de um processador, geralmente através de um único fluxo de controle. Assim, podem explorar apenas o paralelismo de grau mais fino, e dispor de um número elevado de unidades funcionais se torna inútil quando existem dependências de dados ou de controle. O nível de desempenho pode ser elevado, para um mesmo total de unidades funcionais, se estas forem divididas em grupos, cada um com seu próprio conjunto de registradores e fluxo de controle independente. Um efeito colateral altamente desejavel é a redução do número de portas necessário no conjunto de registradores centrais, bem como no tamanho médio da instrução. Apresenta-se resultados para um processador com arquitetura APA, mostrando que se pode obter um desempenho 2,4 vezes melhor em relação a uma configuração monolítica.
Um Multiprocessador Ortogonal Usando DSPs
Authors: Mucheroni Marcos Luiz , Saito José Hiroki
Published: January 2023

Este trabalho mostra uma proposta de implementação de Multiprocessador Ortogonal (OMP) usando quatro processadores TMS 32040 partilhando 16 modulos de memória dispostos em linhas ou colunas, e uma interface barramento EISA usando outros dois TMS com memória global de 4 MWords expansíveis.
Implementação do Padrão Pthreads sobre o Sistema Operacional Mulplix
Authors: Barros Márcio de Oliveira , Aude Júlio Salek
Published: January 2023

POSIX Threads, também conhecido como Pthreads, é um modelo de programação paralela padrão, baseado em multithreading. Este artigo trata da implementação do modelo Pthreads sobre as primitivas de programação paralela Mulplix. Mulplix é o sistema operacional do multiprocessador de memória compartilhada e distribuída Multiplus. Compatibilidade e soluções adotadas na implementação são discutidas. Resultados experimentais comparam a performance da implementação proposta com a implementação do modelo Pthreads para o sistema Solaris.
Detecção de Breakpoints em Programas MPI
Authors: Pinheiro Marcelo L. N. , Drummond Lúcia M. A. , Barbosa Valmir C.
Published: January 2023

O processo ele depuração de programas é vital para o desenvolvimento de aplicações eficientes. São poucas as ferramentas existentes para depuração de programas paralelos distribuídos. Neste trabalho apresentamos uma ferramenta que permite a detecção de breakpoints em programas baseados no padrão MPI. A ferramenta consiste essencialmente em analisar o programa fonte desenvolvido pelo usuário, acrescentando e substituindo código necessário para a posterior execução do mesmo, visando identificar a ocorrência do breakpoint que se tem interesse verificar. São implementados algoritmos para os seguintes tipos de breakpoints: incondicionais, baseados em predicados conjuntivos e disjuntivos. A ferramenta é avaliada através de sua utilização na detecção de breakpoints em uma aplicação paralela baseada em algoritmos genéticos para solução do Travelling Purchaser Problem.
Avaliação da confiabilidade de sistemas compostos de geração-transmissão de energia elétrica em computadores paralelos
Authors: Borges Carmen L. T. , Falcão Djalma M. , Mello João C. O. , Melo Albert C. G.
Published: January 2023

Este trabalho apresenta métodos de análise de confiabilidade de sistemas elétricos de potência compostos de geração/transmissão usando simulação Monte Carlo em computadores paralelos. São discutidas questões relativas à distribuição da carga computacional entre processadores. São propostas três implementações paralelas diferentes, variando principalmente no grafo de tarefas e no controle da convergência paralela. O desempenho de algoritmos síncronos e assíncronos é estudado sobre três sistemas elétricos distintos. Os resultados demonstram ótima eficiência obtida no computador paralelo de memória distribuída IBM RS/6000 SP.
Estimated and Observed Performance of Heuristic Algorithrns for Task Scheduling on Heterogeneous Processors
Authors: Kitajima J. P. W. , Porto S. C. S.
Published: January 2023

Parallel applications with regular and well-known behavior, where task execution time estimates are fairly reliable, are suited to static task scheduling (in opposition to dynamic scheduling, performed during the execution of the application). This is the case of many parallel scientific applications. Task scheduling on a heterogeneous environment, where processors present different processing speeds, is even more complex than on a homogeneous one. Static task scheduling is, thus, performed based on estimated data about the parallel application and the system architecture, and has long taken a heuristic approach. Therefore, a realistic performance evaluation of a task scheduling algorithm can only be fully accomplished if practical results are also considered. In this sense, the present work analyzes the quality of greedy and tabu search task scheduling algorithrns comparing estimated deterministic results with the actual observed makespan of several parallel synthetic applications executing on real parallel machines following the static schedule previously determined.
Avaliando a Técnica de Previsão Dinâmica da Passagem de Locks em Sistemas DSM
Authors: Seidel Cristiana Bentes , Bianchini Ricardo , Amorim Claudio Luis de
Published: January 2023

Em sistemas DSM (Distributed SharEd Memory) o overhead gerado pelo uso de seções críticas está diretamente relacionado ao tempo que um processador fica paralisado dentro de uma seção crítica, esperando por dados provenientes de outros processadores. Para evitar o tempo de espera por dados dentro de uma seção crítica, sem o custo adicional de sobrecarregar a rede com grande quantidade de mensagens, desenvolvemos em um trabalho anterior uma técnica, chamada LAP (Lock Acquirer Prediction), para prever a ordem de aquisição de um determinado lock. Com essa técnica podemos enviar seletivamente as atualizações dos dados compartilhados realizadas dentro da seção crítica para o próximo acquirer do lock. Nesse trabalho mostramos uma avaliação do uso de LAP em sistemas DSM implementados em hardware e em software. Desenvolvemos dois protocolos, Affinity Release Consistency(ARC) para hardware DSM e Affinity Entry Consistency(AEC) para software DSM, e avaliamos o efeito de LAP no desempenho de um conjunto de três aplicações. No protocolo AEC, o uso de LAP obteve reduções de até 28% no tempo total de execução das aplicações testadas. Para o protocolo ARC, desenvolvemos um modelo analítico que provê um limite superior para o ganho de LAP. Mostramos que, em ARC, LAP pode reduzir o tempo de execução das aplicações em até 36%. Concluímos que, para ambos os sistemas, LAP mostrou-se bastante efetiva na redução do tempo gasto dentro da seção crítica obtendo ganhos significativos no tempo total de execução das aplicações.
PVM x MPI: Um Estudo Comparativo em Redes de Workstations
Authors: Rímolo G. S. , Árabe J. N. C.
Published: January 2023

Redes de workstations têm sido consideradas como uma alternativa aos supercomputadores para a execução de aplicações computacionalmente intensivas. Hoje existem várias ferramentas que possibilitam ao usuário a utilização de uma rede de workstations para execução de aplicações paralelas, cada uma apresentando diferentes características em relação ao escalonamento de tarefas, balanceamento de carga, tolerância a falhas, topologia da rede, entre outras. Uma dessas ferramentas é o PVM (Parallel Virtual Machine), amplamente utilizado em todo o mundo. Outro sistema de utiliza-o cada vez mais difundida é o padrão MPl (Message Passing Interface Standard). O objetivo principal deste trabalho é fazer uma análise comparativa entre o PVM e o MPI. Os resultados obtidos mostram que o MPl é mais eficiente para a execução de aplicações paralelas: suas primitivas de comunicação produzem melhores resultados e o seu gerenciamento do buffer de mensagens é mais seguro.
Um modelo distribuído para a alocação e gerência de processadores em multicomputadores
Authors: De Rose César A. F. , Navaux Philippe O. A.
Published: January 2023

Diversos algoritmos para a alocação e gerência dos processadores de uma máquina paralela podem ser encontrados hoje na literatura. Grande parte destes algoritmos já fornece resultados muito bons em relação ao problema de compartilhamento de recursos, porém ainda deixam a desejar em relação a sua escalabilidade. Com o aumento do número de processadores da máquina, a estrutura centralizada utilizada atualmente por estes algoritmos torna-se rapidamente o gargalo do sistema, não permitindo a sua utilização em máquinas maciçamente paralelas. Este trabalho propõe a utilização de um modelo distribuído para a resolução deste problema e analisa o seu comportamento, tanto em nível de desempenho, quanto em nível de qualidade de resultados.
Balanceamento Interno de Carga em um Ambiente Distribuído
Authors: Chaimowicz Luiz , Árabe José Nagib Cotrim
Published: January 2023

Este trabalho faz um estudo detalhado do sistema Dome (Distributed Object Migration Environment), um sistema de programação paralela para redes de workstations. O Dome provê uma biblioteca de objetos distribuídos que possuem mecanismos transparentes de balanceamento de carga e tolerância a falhas. Vários experimentos foram realizados em diversos ambientes de carga enfocando o mecanismo de balanceamento de carga. Para isso foi utilizado um benchmark sintético. Além dos testes com o sistema original, também foram realizadas algumas alterações no Dome com o objetivo de melhorar o seu desempenho. Os resultados obtidos mostram que o Dome é um sistema adequado para execução de programas paralelos em redes de workstations. O uso do seu mecanismo de balanceamento de carga com parâmetros adequados melhora bastante o desempenho dos programas, principalmente em ambientes com carga desbalanceada e instável. As modificações realizadas também produziram resultados positivos, com melhoria no desempenho do sistema na maioria dos casos.