8,828 research outputs found

    Optimal Transmit Power and Channel-Information Bit Allocation With Zeroforcing Beamforming in MIMO-NOMA and MIMO-OMA Downlinks

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    In downlink, a base station (BS) with multiple transmit antennas applies zeroforcing beamforming to transmit to single-antenna mobile users in a cell. We propose the schemes that optimize transmit power and the number of bits for channel direction information (CDI) for all users to achieve the max-min signal-to-interference plus noise ratio (SINR) fairness. The optimal allocation can be obtained by a geometric program for both non-orthogonal multiple access (NOMA) and orthogonal multiple access (OMA). For NOMA, 2 users with highly correlated channels are paired and share the same transmit beamforming. In some small total-CDI rate regimes, we show that NOMA can outperform OMA by as much as 3 dB. The performance gain over OMA increases when the correlation-coefficient threshold for user pairing is set higher. To reduce computational complexity, we propose to allocate transmit power and CDI rate to groups of multiple users instead of individual users. The user grouping scheme is based on K-means over the user SINR. We also propose a progressive filling scheme that performs close to the optimum, but can reduce the computation time by almost 3 orders of magnitude in some numerical examples

    RAPID: Enabling Fast Online Policy Learning in Dynamic Public Cloud Environments

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    Resource sharing between multiple workloads has become a prominent practice among cloud service providers, motivated by demand for improved resource utilization and reduced cost of ownership. Effective resource sharing, however, remains an open challenge due to the adverse effects that resource contention can have on high-priority, user-facing workloads with strict Quality of Service (QoS) requirements. Although recent approaches have demonstrated promising results, those works remain largely impractical in public cloud environments since workloads are not known in advance and may only run for a brief period, thus prohibiting offline learning and significantly hindering online learning. In this paper, we propose RAPID, a novel framework for fast, fully-online resource allocation policy learning in highly dynamic operating environments. RAPID leverages lightweight QoS predictions, enabled by domain-knowledge-inspired techniques for sample efficiency and bias reduction, to decouple control from conventional feedback sources and guide policy learning at a rate orders of magnitude faster than prior work. Evaluation on a real-world server platform with representative cloud workloads confirms that RAPID can learn stable resource allocation policies in minutes, as compared with hours in prior state-of-the-art, while improving QoS by 9.0x and increasing best-effort workload performance by 19-43%

    Small newborns in post-conflict Northern Uganda: Burden and interventions for improved outcomes

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    Introduction: A small newborn can be the result of either a low birthweight (LBW), or a preterm birth (PB), or both. LBW can be due to either a preterm appropriate-for gestational-age (preterm-AGA), or a term small-for-gestational age (term-SGA) or intrauterine growth restriction (IUGR). An IUGR is a limited in-utero foetal growth rates or foetal weight < 10th percentile. Small newborns have an increased risk of dying, particularly in low-resource settings. We set out to assess the burden, the modifiable risk factors and health outcomes of small newborns in the post-conflict Northern Ugandan district of Lira. In addition, we studied the use of video-debriefing when training health staff in Helping Babies Breathe. Subjects and methods: In 2018-19, we conducted a community-based cohort study on 1556 mother-infant dyads, nested within a cluster randomized trial. In our cohort study, we estimated the incidence and risk factors for LBW and PB and the association of LBW with severe outcomes. We explored the prevalence of and factors associated with neonatal hypoglycaemia, as well as any association between neonatal death and hypoglycaemia. In addition, we conducted a cluster randomized trial to compare Helping Babies Breathe (HBB) training in combination with video debriefing to the traditional HBB training alone on the attainment and retention of health worker neonatal resuscitation competency. Results: The incidence of LBW and PB in our cohort was lower than the global estimates, 7.3% and 5.0%, respectively. Intermittent preventive treatment for malaria was associated with a reduced risk of LBW. HIV infection was associated with an increased risk of both LBW and PB, while maternal formal education (schooling) of ≥7 years was associated with a reduced risk of LBW and PB. The proportions of neonatal deaths were many-folds higher among LBW infants compared to their non-LBW counterparts. The proportion of neonatal deaths among LBW was 103/1000 live births compared to 5/1000 among the non-LBW. The prevalence of neonatal hypoglycaemia in our cohort was 2.5%. LBW and PB each independently were associated with an increased risk of neonatal hypoglycaemia. Neonatal hypoglycaemia was associated with an increased risk of hospitalisation and severe outcomes. We demonstrated that neonatal resuscitation training with video debriefing, improved competence attainment and retention among health workers, compared to traditional HBB training alone. Conclusion: In northern Uganda, small infants still have a many-fold higher risk of dying compared to normal infants. In addition, small infants are also at more risk of neonatal hypoglycaemia compared to normal infants. Efforts are needed to secure essential newborn care, should we reach the target of Sustainable Development Goal number 3.2 of reducing infant mortality to less than 12/1000 live births by 2030

    Corporate Social Responsibility: the institutionalization of ESG

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    Understanding the impact of Corporate Social Responsibility (CSR) on firm performance as it relates to industries reliant on technological innovation is a complex and perpetually evolving challenge. To thoroughly investigate this topic, this dissertation will adopt an economics-based structure to address three primary hypotheses. This structure allows for each hypothesis to essentially be a standalone empirical paper, unified by an overall analysis of the nature of impact that ESG has on firm performance. The first hypothesis explores the evolution of CSR to the modern quantified iteration of ESG has led to the institutionalization and standardization of the CSR concept. The second hypothesis fills gaps in existing literature testing the relationship between firm performance and ESG by finding that the relationship is significantly positive in long-term, strategic metrics (ROA and ROIC) and that there is no correlation in short-term metrics (ROE and ROS). Finally, the third hypothesis states that if a firm has a long-term strategic ESG plan, as proxied by the publication of CSR reports, then it is more resilience to damage from controversies. This is supported by the finding that pro-ESG firms consistently fared better than their counterparts in both financial and ESG performance, even in the event of a controversy. However, firms with consistent reporting are also held to a higher standard than their nonreporting peers, suggesting a higher risk and higher reward dynamic. These findings support the theory of good management, in that long-term strategic planning is both immediately economically beneficial and serves as a means of risk management and social impact mitigation. Overall, this contributes to the literature by fillings gaps in the nature of impact that ESG has on firm performance, particularly from a management perspective

    Platform workers and digital agency: Making out on three types of labor platforms

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    Much of the research on platform workers has focused on individuals involved in low-skilled and highly standardized tasks. However, platform workers are not a homogeneous group. Utilizing a classification system that makes a distinction between different layers of platform control and grouping platforms according to how they divide decision rights between platforms and workers, we examine how and for what purposes platform workers operating in three types of control contexts have practiced and developed their digital agency for making out. The study, based on an analysis of platform webpages and 32 semi-structured interviews of food couriers, freelancers, and interim managers, shows that workers can exercise their digital agency on all three types of platforms, but different platforms create different conditions for this depending on their special forms of control. In addition, the forms of control also affect to what extent workers are motivated to direct their agency for making out. Instead of regarding platform work as just another layer of a periphery segment in the labor market, our analysis suggests that platforms exercising algorithmic control are new types of arenas for work, which seem to reproduce, or even amplify, the inequalities found in the offline world of work in the digital world

    Exploring Employees\u27 Perceptions of the Learning Organization and Their Learning Experiences in a Georgia State Government Agency – A Concurrent Mixed Methods Study

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    This concurrent Mixed Methods (MM) research study explored employee learning perceptions and experiences in a state of Georgia government agency. The study used the Dimension of the Learning Organization Questionnaire (DLOQ) to examine employee perceptions of a learning organization across management levels and tenure. It also used semi-structured phenomenological interviews to examine learning experiences. The two questions that framed the study were: (1) How do employees navigate learning individually, in teams, and organizationally? (2) How do employee perceptions of the learning organization compare based on tenure and management level? The concurrent mixed methods design allowed for comparison of findings from the questionnaire and the interviews. Participants were simultaneously recruited from the same state of Georgia government agency to complete the questionnaire and interview voluntarily. Three hundred and thirty-eight (338) employees responded to the questionnaire, the quantitative (QUAN) strand. Five (5) employees participated in the interviews, the qualitative (QUAL) strand. The interview data was analyzed using a hybrid/eclectic methodology of coding, theming, and analytic memos. The questionnaire data was analyzed using descriptive and non-parametric statistical tests. The findings of the study suggest that leadership influences learning critically. For this organization to continue learning and growing, it must focus on the leaderships’ impact on its employees\u27 learning in the work environment. Additionally, significant differences in employee perceptions of the learning organization were observed. These differences were between employees with 6 to 10 years and those with 16 to 20 years of tenure on Inquiry/Dialogue (Dimension 2), Organization Environment Connection (Dimension 6), and Individual Level learning (Level 1). While the findings present possible explanations for the differing perceptions, future research should examine this further

    Stakeholder Governance: Empirical and Theoretical Developments

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    Stakeholder governance receives attention across many disciplines, resulting in fragmented knowledge. The inherent complexity of stakeholder governance requires the integration of this knowledge to develop comprehensive and inclusive theories to better conceptualize this phenomenon. In this research, we develop stakeholder governance through empirical and theoretical approaches. In the first essay, we use multiple case comparisons to empirically examine how and why organizations manage food waste to develop grounded theory through contextualized explanations. We contribute grounded theoretical and empirical evidence to show that food waste represents a significant business problem. Our data suggests that dimensions of logistics and stakeholder governance dictate how and why organizations manage food waste. These findings stimulate a deeper dive into stakeholder governance, revealing fragmentations in knowledge that require holistic, interdisciplinary review and synthesis. In the second essay, we identify definitions and terminologies, review the evolution of theories and orientations, organize mechanisms and conceptualizations, synthesize key theoretical tensions, and offer suggestions for future research to contribute theoretical developments for stakeholder governance. We contribute pluralist conceptual frameworks that integrate knowledge across disciplines to provide a comprehensive overview and recommendations. Overall, we contribute empirical and theoretical research to advance theory development for stakeholder governance
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