3,813 research outputs found

    TANDEM: taming failures in next-generation datacenters with emerging memory

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    The explosive growth of online services, leading to unforeseen scales, has made modern datacenters highly prone to failures. Taming these failures hinges on fast and correct recovery, minimizing service interruptions. Applications, owing to recovery, entail additional measures to maintain a recoverable state of data and computation logic during their failure-free execution. However, these precautionary measures have severe implications on performance, correctness, and programmability, making recovery incredibly challenging to realize in practice. Emerging memory, particularly non-volatile memory (NVM) and disaggregated memory (DM), offers a promising opportunity to achieve fast recovery with maximum performance. However, incorporating these technologies into datacenter architecture presents significant challenges; Their distinct architectural attributes, differing significantly from traditional memory devices, introduce new semantic challenges for implementing recovery, complicating correctness and programmability. Can emerging memory enable fast, performant, and correct recovery in the datacenter? This thesis aims to answer this question while addressing the associated challenges. When architecting datacenters with emerging memory, system architects face four key challenges: (1) how to guarantee correct semantics; (2) how to efficiently enforce correctness with optimal performance; (3) how to validate end-to-end correctness including recovery; and (4) how to preserve programmer productivity (Programmability). This thesis aims to address these challenges through the following approaches: (a) defining precise consistency models that formally specify correct end-to-end semantics in the presence of failures (consistency models also play a crucial role in programmability); (b) developing new low-level mechanisms to efficiently enforce the prescribed models given the capabilities of emerging memory; and (c) creating robust testing frameworks to validate end-to-end correctness and recovery. We start our exploration with non-volatile memory (NVM), which offers fast persistence capabilities directly accessible through the processor’s load-store (memory) interface. Notably, these capabilities can be leveraged to enable fast recovery for Log-Free Data Structures (LFDs) while maximizing performance. However, due to the complexity of modern cache hierarchies, data hardly persist in any specific order, jeop- ardizing recovery and correctness. Therefore, recovery needs primitives that explicitly control the order of updates to NVM (known as persistency models). We outline the precise specification of a novel persistency model – Release Persistency (RP) – that provides a consistency guarantee for LFDs on what remains in non-volatile memory upon failure. To efficiently enforce RP, we propose a novel microarchitecture mechanism, lazy release persistence (LRP). Using standard LFDs benchmarks, we show that LRP achieves fast recovery while incurring minimal overhead on performance. We continue our discussion with memory disaggregation which decouples memory from traditional monolithic servers, offering a promising pathway for achieving very high availability in replicated in-memory data stores. Achieving such availability hinges on transaction protocols that can efficiently handle recovery in this setting, where compute and memory are independent. However, there is a challenge: disaggregated memory (DM) fails to work with RPC-style protocols, mandating one-sided transaction protocols. Exacerbating the problem, one-sided transactions expose critical low-level ordering to architects, posing a threat to correctness. We present a highly available transaction protocol, Pandora, that is specifically designed to achieve fast recovery in disaggregated key-value stores (DKVSes). Pandora is the first one-sided transactional protocol that ensures correct, non-blocking, and fast recovery in DKVS. Our experimental implementation artifacts demonstrate that Pandora achieves fast recovery and high availability while causing minimal disruption to services. Finally, we introduce a novel target litmus-testing framework – DART – to validate the end-to-end correctness of transactional protocols with recovery. Using DART’s target testing capabilities, we have found several critical bugs in Pandora, highlighting the need for robust end-to-end testing methods in the design loop to iteratively fix correctness bugs. Crucially, DART is lightweight and black-box, thereby eliminating any intervention from the programmers

    The Productivity Puzzle, Management Practices and Leadership

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    The research direction of this thesis is sparked by the puzzling variation in productivity among firms, underscoring the importance of understanding the drivers of productivity better. This thesis encompasses three empirical studies, each tackling a distinct challenge in productivity and management research. It is grounded in the framework of the World Management Survey (WMS), which offers a standardized approach to assess management practices and their relation to differences in performance indicators like firm productivity.The first study explores the universality of people management practices within the WMS framework across fourteen countries. It focuses on the role of firm-level human capital, and the cultural values and employment protection legislation in firms’ institutional environment. The results suggest that firms’ human capital is positively associated with people management practices’ effectiveness, and that the practices are universally linked to productivity without being significantly moderated by cultural context or regulatory factors of employment protection.The second study taps into individual managers’ role and investigates the influence of CEOs' instrumental leadership behaviors alongside management practices for firm productivity. Analyzing data from Dutch manufacturing firms, it concludes that both CEO leadership behaviors and management practices independently are associated with productivity, emphasizing the unique roles of CEOs and firm management.The third study examines the link between management practices, productivity, and export performance in Dutch manufacturing firms. It finds that better-managed firms tend to have higher productivity and export revenues, suggesting a relationship between management practices’ role in firm productivity and the heterogeneity in firms’ export performances

    The Comparative Intercultural Sensitivity of American Faculty Teaching Abroad and Domestically : A Mixed-Methods Investigation Employing Participant-Generated Visuals

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    This thesis aimed to identify and compare the intercultural sensitivity, or IS, of tertiary American instructors teaching mono-national, non-American student populations abroad in the UAE and that of American tertiary instructors in multinational, non-American student populations domestically in the US. The study investigated the use of reflexive photography and photo-elicitation interviews methods as both data collection approaches and possible cultivators of IS, as well as any variation in findings between the two participant groups. The study employed a mixed-methods approach involving surveys and semi-structured photo-elicitation interviews following a four-week reflexive photography project. Qualitative data were analyzed through the lens of a developmental framework and inductively through thematic analysis to capture fuller images of participants’ environments. Both groups of participants self-report fairly high IS, with the US-based group’s sensitivity averaging higher than the UAE-based group. Both groups, on average, showed slightly increased IS quantitatively following the reflexive photography project and photo-elicitation interviews, with the UAE-based group experiencing a slightly greater increase. This research involves a small number of participants; findings should be considered for indicative purposes only. Participants’ IS, when observed through the theoretical lens, indicate more progressive sensitivity among US-based participants. Thematic analysis of interview data reflects distinct teaching contexts faced by each participant group, with five and six themes emerging from the UAE- and US-based groups, respectively. This research is the first to the best of the author’s knowledge to investigate the IS of tertiary American faculty teaching internationally diverse student populations domestically and is also the first to compare differences in IS between this group and America

    Climate Change and Critical Agrarian Studies

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    Climate change is perhaps the greatest threat to humanity today and plays out as a cruel engine of myriad forms of injustice, violence and destruction. The effects of climate change from human-made emissions of greenhouse gases are devastating and accelerating; yet are uncertain and uneven both in terms of geography and socio-economic impacts. Emerging from the dynamics of capitalism since the industrial revolution — as well as industrialisation under state-led socialism — the consequences of climate change are especially profound for the countryside and its inhabitants. The book interrogates the narratives and strategies that frame climate change and examines the institutionalised responses in agrarian settings, highlighting what exclusions and inclusions result. It explores how different people — in relation to class and other co-constituted axes of social difference such as gender, race, ethnicity, age and occupation — are affected by climate change, as well as the climate adaptation and mitigation responses being implemented in rural areas. The book in turn explores how climate change – and the responses to it - affect processes of social differentiation, trajectories of accumulation and in turn agrarian politics. Finally, the book examines what strategies are required to confront climate change, and the underlying political-economic dynamics that cause it, reflecting on what this means for agrarian struggles across the world. The 26 chapters in this volume explore how the relationship between capitalism and climate change plays out in the rural world and, in particular, the way agrarian struggles connect with the huge challenge of climate change. Through a huge variety of case studies alongside more conceptual chapters, the book makes the often-missing connection between climate change and critical agrarian studies. The book argues that making the connection between climate and agrarian justice is crucial

    Safe passage for attachment systems:Can attachment security at international schools be measured, and is it at risk?

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    Relocations challenge attachment networks. Regardless of whether a person moves or is moved away from, relocation produces separation and loss. When such losses are repeatedly experienced without being adequately processed, a defensive shutting down of the attachment system could result, particularly when such experiences occur during or across the developmental years. At schools with substantial turnover, this possibility could be shaping youth in ways that compromise attachment security and young people’s willingness or ability to develop and maintain deep long-term relationships. Given the well-documented associations between attachment security, social support, and long-term physical and mental health, the hypothesis that mobility could erode attachment and relational health warrants exploration. International schools are logical settings to test such a hypothesis, given their frequently high turnover without confounding factors (e.g. war trauma or refugee experiences). In addition, repeated experiences of separation and loss in international school settings would seem likely to create mental associations for the young people involved regarding how they and others tend to respond to such situations in such settings, raising the possibility that people at such schools, or even the school itself, could collectively be represented as an attachment figure. Questions like these have received scant attention in the literature. They warrant consideration because of their potential to shape young people’s most general convictions regarding attachment, which could, in turn, have implications for young people’s ability to experience meaning in their lives

    1st Design Factory Global Network Research Conference ‘Designing the Future’ 5-6 October 2022

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    DFGN.R 2022 -Designing the Future - is the first research conference organised by the Design Factory Global Network. The open event offers the opportunity for all like-minded educators, designers and researchers to share their insights and inspire others on education, methods, practices and ecosystems of co-creation and innovation. The DFGN.R conference is a two-day event hosted on-site in Leeuwarden, the Netherlands. The conference is organized alongside International Design Factory Week 2022, the annual gathering of DFGN members. This year's conference is organized in collaboration with Aalto University from Helsinki Finland and hosted by the NHL Stenden University of Applied Sciences

    Conversations on Empathy

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    In the aftermath of a global pandemic, amidst new and ongoing wars, genocide, inequality, and staggering ecological collapse, some in the public and political arena have argued that we are in desperate need of greater empathy — be this with our neighbours, refugees, war victims, the vulnerable or disappearing animal and plant species. This interdisciplinary volume asks the crucial questions: How does a better understanding of empathy contribute, if at all, to our understanding of others? How is it implicated in the ways we perceive, understand and constitute others as subjects? Conversations on Empathy examines how empathy might be enacted and experienced either as a way to highlight forms of otherness or, instead, to overcome what might otherwise appear to be irreducible differences. It explores the ways in which empathy enables us to understand, imagine and create sameness and otherness in our everyday intersubjective encounters focusing on a varied range of "radical others" – others who are perceived as being dramatically different from oneself. With a focus on the importance of empathy to understand difference, the book contends that the role of empathy is critical, now more than ever, for thinking about local and global challenges of interconnectedness, care and justice

    Leadership Development in the African American Church

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    If the Church successfully fulfills its mission, it must have skilled and effective lay leadership. This research intends to examine the Christian organization\u27s enhancement through discipleship and leadership development. Leadership development and discipleship are vital to every church organization. However, research shows that many historically African American denominations are challenged perhaps more than others to find and educate new religious leaders for their congregations (Johnson, 2017, kindle, loc. 179). What most African American pastors have discovered is that aging leadership is prominent in all denominations. The reality is that many African American churches are on life support; they are clinically dead and in need of resuscitation (Johnson, 2017, kindle, loc. 179). In this unprecedented time of opportunity and plentiful resources, the Church is losing influence (Malphurs & Mancini, 2004, p. 7). However, the primary reason is the lack of intentional leadership development. Without influential leadership, people seem destined for a life in which Jesus Christ is little more than an expression uttered in times of frustration or an ancient and personally irrelevant teacher of admirable principles and antiquated religious practices (Malphurs & Mancini, 2004). The purpose of this phenomenological study is to explore how a Christian organization could be enhanced through the leadership development process of emerging and lay leaders, specifically within the African American Baptist Church. Leaders play a vital role in the local Church as they lead believers and nonbelievers to action, helping to move people on God\u27s agenda (Blackaby & Blackaby, 2011, p. 36) while remaining driven to maintain their relationship with Christ and his work

    Examining the Psychosocial Impacts of Transgenerational Trauma: A Phenomenological Study of Parenting Styles Among African American Women

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    This qualitative phenomenological study aimed to examine the psychosocial impacts of unresolved grief and trauma within the dynamics of parenting styles of African American women. The theories used to guide this study include family systems theory, first introduced by Murray Bowen in the 1950s, and attachment theory, developed by John Bowlby in 1969, as they intersect and provide a foundation for understanding emotional bonds, social relationships, and parent-child attachment wounds at the core. This phenomenological qualitative study answered the following central research question: “How has trauma exposure affected African American women’s awareness of their traumas within their lived experience and parenting practices?” Data were collected from 15 African American women. Criteria for this study were participants who were born in the United States, at least 25 years of age, a parent, stepparent, or adoptive parent to one or more children, and have adverse childhood experiences. Audio recordings, participant observations, and a reflective journal were used to collect, organize, and analyze the data. The research findings identified eight themes and 12 subthemes to address awareness of trauma and barriers to counseling. Each theme answered the research questions of this phenomenological study. Results from the study suggested that African American women experience contextually multiple psychosocial and intergenerational factors that influence self-perception, interpersonal relationships, help-seeking attitudes, and parenting practices. The research from this study contributed to the gap in the literature on parenting styles, parent-child attachment across generations, and stress-related disorders in the family dynamics of African American mothers. This study provided recommendations for future research on transgenerational trauma and the psychosocial factors related to the lived experiences of African American women in the parenting role. This study could benefit the field of family counseling to help expand access to culturally appropriate counseling interventions for African American women, their families, the church, and governmental agencies to create culturally responsive mentorship programs. Also, this study could prove particularly beneficial for trauma-informed mental health therapists who work with individuals in this population to improve help-seeking behaviors. Overall, the research findings lead to a more insightful understanding of the impact of unresolved trauma in the family systems of African American women to halt transgenerational trauma
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