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Accelerating Loss Recovery for Content Delivery Network
Get PDFThis article has supplementary downloadable material available at https://doi.org/10.1109/TC.2025.3558020, provided by the authors. Digital Object Identifier 10.1109/TC.2025.3558020Packet losses significantly impact the user experience of content delivery network (CDN) services such as live streaming and data backup-and-archiving. However, our production network measurement studies show that the legacy loss recovery is far from satisfactory due to the wide-area loss characteristics (i.e., dynamics and burstiness) in the wild. In this paper, we propose a sender-side Adaptive ReTransmission scheme, ART, which minimizes the recovery time of lost packets with minimal redundancy cost. Distinguishing itself from forward-error-correction (FEC), which preemptively sends redundant data packets to prevent loss, ART functions as an automatic-repeat-request (ARQ) scheme. It applies redundancy specifically to lost packets instead of unlost packets, thereby addressing the characteristic patterns of wide-area losses in real-world scenarios. We implement ART upon QUIC protocol and evaluate it via both trace-driven emulation and real-world deployment. The results show that ART reduces up to 34% of flow completion time (FCT) for delay-sensitive transmissions, improves up to 26% of goodput for throughput-intensive transmissions, reduces 11.6% video playback rebuffering, and saves up to 90% of redundancy cost.10.13039/501100001809-National Natural Science Foundation of China (Grant Number: 62202473 and 62441230);
Science Fund for Creative Research Groups of the National Natural Science Foundation of China (Grant Number: 62221003);
Key Program of the National Natural Science Foundation of China (Grant Number: 61932016 and 62132011);
National Science Foundation for Distinguished Young Scholars of China (Grant Number: 62425201)
Concept and preliminary structural analysis of a crater-covering dome for future lunar habitats
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The datasets utilised and/or analysed during the current study are available from the corresponding author upon reasonable request.The prospect of establishing a human presence on the Moon has transitioned from the realm of science fiction to an achievable goal. The long-term objective of the Artemis program is to establish a habitat on the Moon that would enable crews to remain on the lunar surface for extended periods. The developmental pathway for such facilities culminates in structures that are manufactured and constructed predominantly from materials sourced on the lunar surface, in alignment with the In-Situ Resource Utilization (ISRU) concept. This paper presents a conceptual lunar habitat that was created by covering 17 m diameter crater in the Mare Tranquillitatis with a structure made from a lunar regolith-based geopolymer. Five shapes of the covering lid were analysed, including: two concave domes with rises of 0.5 m and 1 m; a flat circular slab; and two convex domes with rises of 0.5 m and 1 m. Structural analysis was performed using the Finite Element Method, employing material data from existing literature as well as original strength tests of alkali-activated material based on lunar regolith simulants conducted by the authors. Each model of structure was subjected to dead loads and varying levels of internal air pressure. The numerical analysis revealed the advantages of concave-shaped structures, where internal pressure induced compressive stress within the cross-section, thereby mitigating the risks of air leakage and decompression of the habitat and taking advantage of material in which compressive strength is higher than tensile strength.Research funded by Silesian University of Technology, grant number: 03/020/BKM24/0174. The collaboration resulted from CSTO2NE project co-funded by Horizon Europe MSCA Staff Exchange GA No. 101086302 and a grant from the Ministry of Science and Higher Education of the Republic of Poland under the name “International Co-financed Projects No. 5470/HE/2023/2”
On Compulsory Licensing of Trade Secrets to Safeguard Public Health
No full textA preprint version of the article is available at SSRN: https://ssrn.com/abstract=4771745 . It has not been certified by peer review.In the pharmaceutical sector an increasing number of new medicines are large-molecule products, namely biologics derived from living organisms, rather than small-molecule drugs synthesised from chemicals. Unlike small-molecule medicines, which are relatively easy to manufacture, large-molecule products are less stable and harder to produce. We investigate whether the current UK legal system provides an appropriate balance between the protection provided to technology owners and the public interest in accessing medical technologies, especially in times of emergencies. At present, UK law facilitates compulsory licensing of patents but has no equivalent scheme for trade secrets. Our analysis of the legal constraints on potential reforms suggests that a mechanism for compulsory licensing of trade secrets would be compatible with UK domestic law, the European Convention on Human Rights, the World Trade Organization Agreement on Trade-Related Aspects of Intellectual Property Rights and other international agreements, provided appropriate safeguards are put in place to balance the rights of intellectual property holders with the public interest. The article contributes a detailed framework for the compulsory licensing of trade secrets, drawing parallels with voluntary technology transfer agreements, including provisions for defining the scope of transfer, maintaining confidentiality, restricting future use, providing fair compensation and ensuring enforceability
“Space invaders” revisited: counter-narratives of two (b)older south Asian female academics
Get PDFIn this paper, we revisit Puwar’s concept of “space invader” as two (b)older South Asian female academics at a later stage in their professional lives. Drawing on Critical Race Theory and a counter-storytelling approach, we reflexively narrate our analysis of a series of research conversations through the catalyst of “space invader”, and how this led us to explore stages of voice across space and time. Including conversational metaphors in places, we proudly centre our mother tongue languages (Hindi and Panjabi) as we reflect through the scents of our storied memories. We discuss how our professional and community-based equity roles and experiences entwine as an embodiment of driving racial justice. We use metaphoric hooks to chart our herstories of hope as we navigate White fragility and often hostile spaces, seeking refuge in “safe” and supportive spaces as a form of collective healing through speaking, listening and simply being “ourselves”. Through our research conversations, we analyse the traumas, isolation and contentment of working at the margins of decision-making spaces, and the challenges of “trespassing” across boundaries towards the centre, where we have never really belonged, yet courageously taken the journey. “Space Invaders” revisited has required us both to analyse the painful racialised memories of our bodies, minds and souls, the visceral violence of racism, the silencing (and confident roars) of our voices, and racial battle fatigue
Energy Minimization for UAV-Enabled Covert Offloading MEC Systems
Get PDFIn this work, a covert offloading framework is established for unmanned aerial vehicle (UAV) system. Specifically, one UAV-enabled mobile edge computing (MEC) server is deployed to assist the offloading for multiple ground users, while the offloading behavior might be exposed and detected due to the existence of a malicious warden. To enhance the covertness, each user splits a part of its power to transmit jamming signal, and the relationship between users' power split ratio and the warden's minimum detection error probability (DEP) is investigated. Then, an efficient energy minimization algorithm is designed by optimizing users' power split, computing resource allocation and deployment of the UAV-MEC server jointly, subject to specific covertness, power and transmission rate constraints. Finally, simulation results are provided to demonstrate the effectiveness of our covert offloading design.This work was supported in part by the National Key R&D Program
of China under Grant 2023YFB2603500, in part by the National Natural
Science Foundation of China under Grant 62271419, Grant 62301462, Grant 62361136810, and Grant U2268201, in part by UKRI Postdoc Guarantee.
project S-ISAC [grant number EP/Z002435/1] and EU MSCA Postdoctoral
Fellowships [grant number 101154926]
Residual Income Valuation and Stock Returns. Evidence from a Value-to-Price Investment Strategy
Get PDFJEL classification: G11, G12, G14.This is a working paper. It is not certified by peer review.This paper contributes to the accounting and asset pricing anomalies literature by investigating the performance of value-to-price strategies, and the relationship between value-to-price ratio and several risk proxies. If the value-to-price ratio successfully predicts future returns at stock level, we hypothesize that portfolio sorts based on the V/P ratio generate excess returns and consist of companies that are undervalued for prolonged periods. Overlapping and non-overlapping returns are used to test the risk/mispricing explanation of the value-to-price strategy. Results, for the US market from 1987 to 2015, show that high V/P portfolios outperform low V/P portfolios across horizons extending from one to three years. The V/P ratio is positively correlated to future stock returns after controlling for several firm characteristics, which are well known risk proxies. Findings also indicate that profitability and investment add explanatory power to the Fama and French three factor model and for stocks with V/P ratio close to 1. However, these factors cannot explain all variation in excess returns especially for years two and three and for stocks with high V/P ratio. Finally, portfolios with the highest V/P stocks pick companies that are significantly mispriced relative to their equity (investment) and profitability growth persistence in the future
Comprehensive Review of Control Techniques for Various Mechanisms of Parallel Robots
Get PDFThis study provides a literature review of control schemes associated with parallel robots. Various types of parallel robots have been discussed, including the Delta Robot, 2 DOF Parallel Robot, 3 DOF Parallel Robot, 4 DOF Parallel Robot, the R4 Redundantly Parallel Robot, the 5R Parallel Robot, 6 DOF Parallel Robot (Hexa Robot), Cable-Driven Parallel Robot, and Parallel Quadruped Robot. Additionally, an overview of the control structuring within these systems has been provided. This study covers the developments occurring between 2008 and 2024. These controllers are PI Control, PID Control, Genetic Algorithm Optimized PID Control, Extended PD Control, Augmented Nonlinear PD Control, Model-Based PD Control, Synchronous PD Control Based on a Time-Delay Estimator, Identification-Based Control, Image-Based Control, Lagrangian Formulation-Based Control, Observers-Based Control, Optimal PID Control, Anti-Windup Based PID Control, Model-Based Control, PLC-Based Control Architecture, Feedback PID Control, and Computed Torque Control, Hedge Algebras Control, B-Spline Neural Network Control, Fuzzy Logic Control, Model-Based control, Cooperative Control, Brain Emotional Learning-Based Intelligent Control, Nonlinear Model Predictive Control, Fuzzy Logic-Based Sliding Surface Control, Fuzzy PID Control, Fuzzy- Based PID Control, Interval Type-2 Fuzzy Logic Control Fuzzy Logic based Neural Network Control, Nonlinear Model Predictive Control, Synchronous Sliding Mode Control, Observer-Based Sliding Mode Control, Sliding Mode-Based on Backstepping Control, LQ Optimal Control, Adaptive Fuzzy Control, Rise Feedback Control, Dual-Space Feedforward Control, Dual-Space Feedforward Control in the Cartesian Space, Dual-Space Feedforward Control, Dual Mode Adaptive Control, Nonlinear Dual Mode Adaptive Control, Optimized Fuzzy Adaptive PID Control, Adaptive Position-Force Control, Adaptive Admittance Control, and Robust Nonlinear Adaptive Control, Adaptive Robust Control, Adaptive Control, and Adaptive Terminal Sliding Mode Control, Robust control, fault tolerant controllers, and passivity control. The primary contribution is a literature review of control-based strategies for parallel robots, designed to inform those interested in control-oriented parallel robot research
Valorising excavated low-grade waste clay in limestone calcined clay cement system for 3D printing applications
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Data will be made available on request.Limestone calcined clay cement (LC3) presents a suitable low-carbon cementitious material for large-scale 3D printing due to its long open time. This study investigates the impact of substituting up to 100 % natural aggregate with recycled brick aggregates (BA) on the engineering properties, durability and printing properties of LC3. BA's rough surface and irregular shape reduced the workability of the LC3 mixtures even though the water absorption of BA was compensated for by adding extra water. The mechanical strength increased significantly in the presence of BA of around 36 %–62 %. Moreover, incorporating BA was found to boost the hydration and allowed it continue due to the presence of additional water in its microstructure. The water absorptions of LC3 prepared with up to 70 % replacement level of aggregates with BA were comparable to the reference mix, while a 100 % replacement level increased the water absorption by around 9 %. In contrast, incorporating BA improved the freeze-thaw resistivity by up to 25 %. Moreover, it was found that incorporating BA improved the layer quality of 3D-printed filaments. The results of this study present a breakthrough in the recycling of brick aggregates in LC3 systems for both cast and 3D printing applications, which will help develop a more environmentally friendly mixture with high engineering performance
The political economy of group domination and pre-electoral violence
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Not applicableJEL Classification: D72, D74, F50.Supplementary Information is available online at: https://link.springer.com/article/10.1007/s00148-025-01125-z#Sec15 .We construct a theoretical model to study the effects of pre-electoral violence in a political economy set-up. In an environment pervaded by ethnic cleavages, we model violence in terms of a group destroying the rival group’s production potential, which impairs that group’s productivity not only in material terms but also by breaking the targeted group’s cohesion and morale through fear and intimidation. We show that the destruction perpetrated by either group is increasing in their rival’s productivity, and is decreasing in the potential uncertainty surrounding the political process, in their own group’s share of the population, and in the degree of authoritarianism of the studied society. Our case studies on Zimbabwe, Kenya, and Nigeria provide support to our theory
Environmental and economic sustainability assessment of food waste management options in a tortilla industry (a case study)
Get PDFThe aim of this study is to analyse the waste generated in tortilla production process in a tortilla industry located in London and consider a number of potential solutions. This study evaluated the environmental and economic impacts related to anaerobic digestion, using the food waste as animal feed, and reworking the food waste. The impacts of each waste management options were compared to determine the most sustainable option. The Life Cycle Assessment (LCA) and Life Cycle Costs (LCC) methods have been applied using SimaPro 9.3.0.3. The functional unit of the study was set to 1 kg of tortilla. The system boundary included the tortilla production processes (mixing, forming, baking, cooling and packaging) and food waste management scenarios. The LCA results showed that reworking the waste will substantially reduce environmental impacts across all assessed categories. The LCC results show that reworking the food waste within the tortilla production process is the best option with the lowest net costs of GBP4.96/kg. This is followed by AD with a net cost of GBP 5.08/kg and lastly by animal feed with a net cost of GBP 6.45/kg.This project was funded by the BBSRC-CDT (Project ref number: BB/V011391/1) and ESPRC through the Park Royal Net Zero Food Systems
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