Miracle-dz/UniFAR-FTUs huggingface dataset:
All Pairs Routing Path Enumeration using Latin Multiplication and Julia

Enumerating all routing paths among Autonomous Systems (ASes) at an Internet-scale is an intractable problem. The Border Gateway Protocol (BGP) is the standard exterior gateway protocol through which ASes exchange reachability information. Building an efficient path enumeration tool for a given network is an essential step towards estimating the network’s resiliency to cybersecurity attacks, such as routing origin and path hijacking. In our work, we use the matrix Latin-Multiplication method to compute all possible paths among all pairs of nodes. We parallelize this computation through the domain decomposition for matrix multiplication and implement our solution in the Julia high performance programming language. We run experiments at both the AS and the router level. We also simulate an AS-origin attack and calculate the effect on the network paths. Our preliminary results provide positive evidence for the applicability of the method, while we make our implementation code publicly available.
Zoned FTL: Achieve Resource Isolation via Hardware Virtualization

NVMe Solid-State Drives (SSDs) offer unprecedented throughput and response time for data centers. To increase resource utilization and enable necessary isolation, service providers usually accommodate multiple Virtual Machines (VMs) and lightweight containers on the same physical server. Till today, providing predictable storage performance is still challenging as commercial datacenter NVMe SSDs still appear as black-box block devices. This motivates us to re-examine the I/O stack and firmware design, discuss and quantify the root causes of performance interference. We argue that the semantic gap between predictable performance and the underlying device must be bridged to address this challenge. We propose a split-level design, Zoned FTL (), which enables strong physical isolation for multiple virtualized services with minimal changes in existing storage stacks. We implement the prototype on an SSD emulator and evaluate it under a variety of multi-tenant environments. The evaluation results demonstrate that barely impacts the raw performance while delivering up to 1.51x better throughput and reduce the 99th percentile latency by up to 79.4% in a multi-tenancy environment.
Boosting Inter-process Communication with Architectural Support

IPC (inter-process communication) is a critical mechanism for modern OSes, including not only microkernels such as seL4, QNX, and Fuchsia where system functionalities are deployed in user-level processes, but also monolithic kernels like Android where apps frequently communicate with plenty of user-level services. However, existing IPC mechanisms still suffer from long latency. Previous software optimizations of IPC usually cannot bypass the kernel that is responsible for domain switching and message copying/remapping across different address spaces; hardware solutions such as tagged memory or capability replace page tables for isolation, but usually require non-trivial modification to existing software stack to adapt to the new hardware primitives. In this article, we propose a hardware-assisted OS primitive, XPC (Cross Process Call), for efficient and secure synchronous IPC. XPC enables direct switch between IPC caller and callee without trapping into the kernel and supports secure message passing across multiple processes without copying. We have implemented a prototype of XPC based on the ARM AArch64 with Gem5 simulator and RISC-V architecture with FPGA boards. The evaluation shows that XPC can reduce IPC call latency from 664 to 21 cycles, 14×–123× improvement on Android Binder (ARM), and improve the performance of real-world applications on microkernels by 1.6× on Sqlite3.
Development and Use of Domain-specific Learning Theories, Models, and Instruments in Computing Education

Use of theory within a field of research provides the foundation for designing effective research programs and establishing a deeper understanding of the results obtained. This, together with the emergence of domain-specific theory, is often taken as an indicator of the maturity of any research area. This article explores the development and subsequent usage of domain-specific theories and theoretical constructs (TCs) in computing education research (CER). All TCs found in 878 papers published in three major CER publication venues over the period 2005–2020 were identified and assessed to determine the nature and purpose of the constructs found. We focused more closely on areas related to learning, studying, and progression, where our analysis found 80 new TCs that had been developed, based on multiple epistemological perspectives. Several existing frameworks were used to categorize the areas of CER focus in which TCs were found, the methodology by which they were developed, and the nature and purpose of the TCs. A citation analysis was undertaken, with 1,727 citing papers accessed to determine to what extent and in what ways TCs had been used and developed to inform subsequent work, also considering whether these aspects vary according to different focus areas within computing education. We noted which TCs were used most often and least often, and we present several brief case studies that demonstrate progressive development of domain-specific theory. The exploration provides insights into trends in theory development and suggests areas in which further work might be called for. Our findings indicate a general interest in the development of TCs during the period studied, and we show examples of how different approaches to theory development have been used. We present a framework suggesting how strategies for developing new TCs in CER might be structured and discuss the nature of theory development in relation to the field of CER.
An Application-oblivious Memory Scheduling System for DNN Accelerators

Deep Neural Networks (DNNs) tend to go deeper and wider, which poses a significant challenge to the training of DNNs, due to the limited memory capacity of DNN accelerators. Existing solutions for memory-efficient DNN training are densely coupled with the application features of DNN workloads, e.g., layer structures or computational graphs of DNNs are necessary for these solutions. This would result in weak versatility for DNNs with sophisticated layer structures or complicated computation graphs. These schemes usually need to be re-implemented or re-adapted due to the new layer structures or the unusual operators in the computational graphs introduced by these DNNs. In this article, we review the memory pressure issues of DNN training from the perspective of runtime systems and model the memory access behaviors of DNN workloads. We identify the iterative, regularity, and extremalization properties of memory access patterns for DNN workloads. Based on these observations, we propose AppObMem, an application-oblivious memory scheduling system. AppObMem automatically traces the memory behaviors of DNN workloads and schedules the memory swapping to reduce the memory pressure of the device accelerators without the perception of high-level information of layer structures or computation graphs. Evaluations on a variety of DNN models show that, AppObMem obtains 40–60% memory savings with acceptable performance loss. AppObMem is also competitive with other open sourced SOTA schemes.
DuoMC: Tight DRAM Latency Bounds with Shared Banks and Near-COTS Performance

DRAM memory controllers (MCs) in COTS systems are designed primarily for average performance, offering no worst-case guarantees, while real-time MCs provide timing guarantees at the cost of a significant average performance degradation. For this reason, hardware vendors have been reluctant to integrate real-time solutions in high-performance platforms. In this paper, we overcome this performance-predictability trade-off by introducing DuoMC, a novel memory controller that promotes to augment COTS MCs with a real-time scheduler and run-time monitoring to provide predictability guarantees. Leveraging the fact that the resource is barely overloaded, DuoMC allows the system to enjoy the high-performance of the conventional MC most of the time, while switching to the real-time scheduler only when timing guarantees risk being violated, which rarely occurs. In addition, unlike most existing real-time MCs, DuoMC enables the utilization of both private and shared DRAM banks among cores to facilitate communication among tasks. We evaluate DuoMC using a cycle-accurate multi-core simulator. Results show that DuoMC can provide better or comparable latency guarantees than state-of-the-art real-time MCs with limited performance loss (only 8% in the worst scenario) compared to the COTS MC.
Unsupervised Graph-Based Entity Resolution for Complex Entities

Entity resolution (ER) is the process of linking records that refer to the same entity. Traditionally, this process compares attribute values of records to calculate similarities and then classifies pairs of records as referring to the same entity or not based on these similarities. Recently developed graph-based ER approaches combine relationships between records with attribute similarities to improve linkage quality. Most of these approaches only consider databases containing basic entities that have static attribute values and static relationships, such as publications in bibliographic databases. In contrast, temporal record linkage addresses the problem where attribute values of entities can change over time. However, neither existing graph-based ER nor temporal record linkage can achieve high linkage quality on databases with complex entities, where an entity (such as a person) can change its attribute values over time while having different relationships with other entities at different points in time. In this article, we propose an unsupervised graph-based ER framework that is aimed at linking records of complex entities. Our framework provides five key contributions. First, we propagate positive evidence encountered when linking records to use in subsequent links by propagating attribute values that have changed. Second, we employ negative evidence by applying temporal and link constraints to restrict which candidate record pairs to consider for linking. Third, we leverage the ambiguity of attribute values to disambiguate similar records that, however, belong to different entities. Fourth, we adaptively exploit the structure of relationships to link records that have different relationships. Fifth, using graph measures, we refine matched clusters of records by removing likely wrong links between records. We conduct extensive experiments on seven real-world datasets from different domains showing that on average our unsupervised graph-based ER framework can improve precision by up to 25% and recall by up to 29% compared to several state-of-the-art ER techniques.
Voice Fingerprinting for Indoor Localization with a Single Microphone Array and Deep Learning

With the fast development of the Internet of Things (IoT), smart speakers for voice assistance have become increasingly important in smart homes, which offers a new type of human-machine interaction interface. Voice localization with microphone arrays can improve smart speaker's performance and enable many new IoT applications. To address the challenges of complex indoor environments, such as non-line-of-sight (NLOS) and multi-path propagation, we propose voice fingerprinting for indoor localization using a single microphone array. The proposed system consists of a ReSpeaker 6-mic circular array kit connected to a Raspberry Pi and a deep learning model, and operates in offline training and online test stages. In the offline stage, the models are trained with spectrogram images obtained from audio data using short-time Fourier transform (STFT). Transfer learning is used to speed up the training process. In the online stage, a top-K probabilistic method is used for location estimation. Our experimental results demonstrate that the Inception-ResNet-v2 model can achieve a satisfactory localization performance with small location errors in two typical home environments.
Contribution to stability analysis of power hardware-in-the-loop simulators

This study establishes a new basis for understanding the stability of power hardware-in-the-loop (PHIL) systems considering their hybrid (analogue/digital) nature. Such systems are known to have closed-loop stability issues due to delays between the simulator and the power amplifier (PA). This work demonstrates that the conventional method for determining the stability criterion, which considers the system as a continuous model, is not appropriate. A new method of assessing the stability of a PHIL system based on discrete-time impedance frequency responses is thus presented. Hydro-Quebec's Research Institute will use this innovative approach for the development of its own PHIL system, which will involve connecting the institute's real-life experimental distribution test line to its large-scale real-time digital simulator through a 25-kV, 10-MVA PA. The validity of the new method is demonstrated for simulation models of a well-known inductive system and of a distribution feeder connected to a large-scale power system.
Wind turbine power performance measurement with the use of spinner anemometry

The spinner anemometer is an instrument for yaw misalignment measurements without the drawbacks of instruments mounted on the nacelle top. The spinner anemometer uses a non-linear conversion algorithm that converts the measured wind speeds by three sonic sensors on the spinner to horizontal wind speed, yaw misalignment and flow inclination angle. The conversion algorithm utilizes two constants that are specific to the spinner and blade root design and to the mounting positions of the sonic sensors on the spinner. One constant, k2, mainly affects the measurement of flow angles, while the other constant, k1, mainly affects the measurement of wind speed. The ratio between the two constants, k ̨ D k2=k1, however, only affects the measurement of flow angles. The calibration of k ̨ is thus a basic calibration of the spinner anemometer. Theoretical background for the non-linear calibration is derived from the generic spinner anemometer conversion algorithm. Five different methods were evaluated for calibration of a spinner anemometer on a 500 kW wind turbine. The first three methods used rotor yaw direction as reference angular, while the wind turbine, was yawed in and out of the wind. The fourth method used a hub height met-mast wind vane as reference. The fifth method used computational fluid dynamics simulations. Method 1 utilizing yawing of the wind turbine in and out of the wind in stopped condition was the preferred method for calibration of k ̨ . The uncertainty of the yaw misalignment calibration was found to be 10%, giving an uncertainty of 1ı at a yaw misalignment of 10ı. © 2014 The Authors. Wind Energy published by John Wiley & Sons, Ltd.
Effect of Load Eccentricity on Stress Condition of Butt Welded Joint with Asymmetrical Reinforcement

Abstract An analytical method for determination of a stress condition of butt welded thin-gauge plates with asymmetrical reinforcement is developed. The proposed method allows take into account the effect of the load application eccentricity on the tensile stress concentration factor (SCF) in the weld root zone. It is presented that the bending stresses, caused by this eccentricity, result in increasing the total stresses up to 75%. The results of analytical SCF calculations are in good agreement with the results obtained using the finite element method.
Conservative (non‐surgical) management of cryptoglandular anal fistulas: is it possible? A new insight and direction

Medical treatment has no role in anal fistula management. Many anal fissures, even advanced ones, can be treated by a regimen of local and oral antibiotics with avoidance of constipation (LOABAC). As early intersphincteric fistulas can develop from deepening of anal fissures, we tested whether these early fistulas may be treated with the same regimen (LOABAC). Patients of grade I anal fistulas (intersphincteric fistulas with size <2 cm and no external opening) who were not willing for surgery were managed with LOABAC regimen and then followed up (Fig. 1). Such fistulas with no external opening and only intersphincteric component had been categorized as grade I fistulas by Parks et al. Ethics committee approval was taken from the Indus International Ethics Committee via reference number EC/IIH-IEC/ SP-16. LOABAC regimen include the following: • Local antibiotics – topically (povidone–iodine plus ornidazole cream) applied on the fistula opening in the anal canal twice a day for 3 months. • Oral antibiotics – ciprofloxacin and ornidazole on 12 hourly dose for 5 days. • Avoidance of constipation – a high-fibre diet plus a strict regimen of 20 g ispaghula husk (psyllium fibre) once a day. Seven grade 1 fistula patients were managed with LOABAC regimen (Fig. 1). (mean age 44.5 12.3 years, five males, median follow-up 24 months (12–84), five posterior and two anterior fistulas). One patient was lost to follow-up, the fistula remained healed in four patients and the fistulas progressed to form abscesses necessitating surgery in two patients. Thus, four of six patients remained healed on long-term follow-up. This small retrospective case series highlights a novel viewpoint that a subset of early anal fistulas (grade I intersphincteric fistulas with size <2 cm and no external opening) can perhaps be treated with medical management. Although no conclusive treatment strategy can be made based on this experience, yet the prime purpose of this study is that it puts across a viewpoint that medical management in anal fistulas is possible and merits further research.
Pulse-shaping techniques of high-g-value acceleration generators

A Hopkinson pressure bar device was utilized in high overloading tests for initiators as a high-g-value acceleration generator.And a finite element model was created to simulate the operation process of producing acceleration pulses.The effects of the bullets and the pulse shapers on the loading pulses were investigated by considering the shapes of the bullets as well as the materials,diameters and thicknesses of the pulse shapers,respectively.To realize the purpose of effectively controlling and improving the loading environment in impact tests for initiators,the required acceleration pulses were obtained.So the investigated results can provide a basis for experimental designations and tests to check the reliability of initiators in impact environments.
Predictors and Outcomes of Salvaging the Corticospinal Tract After Thrombectomy in Basilar Artery Occlusion Stroke

Background Regional eloquence of brainstem structures may contribute to neurological status in basilar artery occlusion (BAO) stroke. The corticospinal tract (CST) which is vulnerable to BAO is important for motor activity. This study investigated the impact of CST salvage on outcomes and its associated factors in patients with BAO treated with thrombectomy. Methods We retrospectively investigated 88 patients with BAO admitted ≤24 h after onset and presented with motor deficits and who underwent thrombectomy. Patients with a pre-stroke modified Rankin Scale (mRS) score of 4–5 who did not undergo baseline brain computed tomography angiography were excluded. CST salvage was evaluated using follow-up imaging (magnetic resonance imaging [MRI] or computed tomography when MRI was not available) after thrombectomy. A good outcome was defined as a 3-month mRS score of ≤2 or 3 if a patient's pre-stroke mRS score was 3. The associations between CST salvage and outcomes and clinical parameters were analyzed using logistic regression analyses. Results Thirty-nine (44.3%) patients had CST salvage and the same number of patients had good outcomes. CST salvage was independently associated with a good outcome [adjusted odds ratio (aOR): 18.52, 95% confidence interval (CI): 4.31–79.67, p < 0.001]. After adjusting for confounders, atrial fibrillation (aOR: 3.92, 95% CI: 1.18–13.00, p = 0.026), location of occlusion (mid-BAO; aOR: 0.21, 95% CI: 0.06–0.72, p = 0.013), length of occlusion (involved segment of BAO <2; aOR: 4.77, 95% CI: 1.30–17.59, p = 0.019), and onset-to-puncture-time ≤180 min (aOR: 4.84, 95% CI: 1.13–20.75, p = 0.034) were significantly associated with CST salvage. Conclusion CST salvage was associated with good functional outcomes in patients with BAO treated with thrombectomy. The presence of atrial fibrillation, location and length of BAO may predict CST salvage after thrombectomy, and rapid treatment with thrombectomy may protect this eloquent tract in these patients.
How Media Use Influences the Fertility Intentions Among Chinese Women of Reproductive Age: A Perspective of Social Trust

Background The low fertility level has become a serious social problem in China. Previous research has argued the significant influence of media use and social trust on fertility intentions, but the interaction between the two variables and how they influence fertility intentions remain further investigation. This study explored the influence mechanism of media use on Chinese women's fertility intentions from the perspective of social trust. Methods This study collected data from the 2017 China General Social Survey, investigated the relationships between variables through bivariate correlation coefficients, and explored the differences in fertility intentions among women of reproductive age (20–49). Also, this paper examined the influence of media use and social trust by regression analysis and tested the mediating role of social trust between media use and fertility intentions with Bootstrap sampling. Results Women with different media use preferences, education levels, and family incomes have significant differences (p < 0.01) in fertility intentions. New media use negatively influences women's fertility intentions, while traditional media use has no significant influence on women's fertility intentions. Social trust significantly influenced women's fertility intentions and partially mediated the impact of new media use on fertility intentions. Conclusion Online communication influences fertility intentions among Chinese women of reproductive age. It tends to influence their social trust by amplifying negative social news, affecting their fertility intentions further. This paper suggests the importance of strengthening social trust and online agenda-setting to improve women's fertility intentions that strategic information communication can change their perceptions of social trust.