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Mean Field and Refined Mean Field Approximations for Heterogeneous systems: It Works!

proceedings of the acm on measurement and analysis of computing systems 2022年第1期6卷 1–43页

作者： Allmeier, Sebastian Gast, Nicolas Univ Grenoble Alpes CNRS INRIA F-38000 Grenoble France

Mean field approximation is a powerful technique to study the performance of large stochastic systems represented as n interacting objects. Applications include load balancing models, epidemic spreading, cache replacement policies, or large-scale data centers. Mean field approximation is asymptotically exact for systems composed of n homogeneous objects under mild conditions. In this paper, we study what happens when objects are heterogeneous. This can represent servers with different speeds or contents with different popularities. We define an interaction model that allows obtaining asymptotic convergence results for stochastic systems with heterogeneous object behavior, and show that the error of the mean field approximation is of order O(1/n). More importantly, we show how to adapt the refined mean field approximation, developed by Gast et al., and show that the error of this approximation is reduced to O(1/n(2)). To illustrate the applicability of our result, we present two examples. The first addresses a list-based cache replacement model, RANDOM(m), which is an extension of the RANDOM policy. The second is a heterogeneous supermarket model. These examples show that the proposed approximations are computationally tractable and very accurate. They also show that for moderate system sizes (n approximate to 30) the refined mean field approximation tends to be more accurate than simulations for any reasonable simulation time.

关键词： Mean Field Refined Mean Field Heterogeneity Mean Field Models Load Balancing Cache Replacement Policies Mean Estimation

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ChirpKey: A Chirp-level Information-based Key Generation Scheme for LoRa Networks via Perturbed Compressed Sensing 42

ChirpKey: A Chirp-level Information-based Key Generation Sch...

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42nd IEEE International Conference on Computer Communications, INFOCOM 2023

作者： Yang, Huanqi Sun, Zehua Liu, Hongbo Xia, Xianjin Zhang, Yu Gu, Tao Hancke, Gerhard Xu, Weitao City University of Hong Kong Shenzhen Research Institute Hong Kong City University of Hong Kong Department of Computer Science Hong Kong University of Electronic Science and Technology of China School of Computer Science and Engineering China The Hong Kong Polytechnic University Department of Computing Hong Kong Macquarie University School of Computing Australia

ISBN: (纸本)9798350334142

Physical-layer key generation is promising in establishing a pair of cryptographic keys for emerging LoRa networks. However, existing key generation systems may perform poorly since the channel reciprocity is critically impaired due to low data rate and long range in LoRa networks. To bridge this gap, this paper proposes a novel key generation system for LoRa networks, named ChirpKey. We reveal that the underlying limitations are coarse-grained channel measurement and inefficient quantization process. To enable fine-grained channel information, we propose a novel LoRa-specific channel measurement method that essentially analyzes the chirp-level changes in LoRa packets. Additionally, we propose a LoRa channel state estimation algorithm to eliminate the effect of asynchronous channel sampling. Instead of using quantization process, we propose a novel perturbed compressed sensing based key delivery method to achieve a high level of robustness and security. Evaluation in different real-world environments shows that ChirpKey improves the key matching rate by 11.03-26.58% and key generation rate by 27-49× compared with the state-of-the-arts. Security analysis demonstrates that ChirpKey is secure against several common attacks. Moreover, we implement a ChirpKey prototype and demonstrate that it can be executed in 0.2 s. © 2023 IEEE.

关键词： Compressed sensing

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danceON: Culturally Responsive Creative computing 21

danceON: Culturally Responsive Creative Computing

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CHI Conference on Human Factors in computing systems

作者： Payne, William Christopher Bergner, Yoav West, Mary Etta Charp, Carlie Shapiro, R. Benjamin Benjamin Szafir, Danielle Albers Taylor, Edd, V DesPortes, Kayla NYU Brooklyn NY 11201 USA Univ Colorado Boulder CO 80309 USA

ISBN: (纸本)9781450380966

Dance provides unique opportunities for embodied interdisciplinary learning experiences that can be personally and culturally relevant. danceON is a system that supports learners to leverage their body movement as they engage in artistic practices across data science, computing, and dance. The technology includes a Domain Specific Language (DSL) with declarative syntax and reactive behavior, a media player with pose detection and classification, and a web-based IDE. danceON provides a low-foor allowing users to bind virtual shapes to body positions in under three lines of code, while also enabling complex, dynamic animations that users can design working with conditionals and past position data. We developed danceON to support distance learning and deployed it in two consecutive cohorts of a remote, two-week summer camp for young women of color. We present our findings from an analysis of the experience and the resulting computational performances. The work identifies implications for how design can support learners' expression across culturally relevant themes and examines challenges from the lens of usability of the computing language and technology.

关键词： computing education data literacy dance culturally responsive pedagogy design based research

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Identifying Casualty Changes in Software Patches 2021

Identifying Casualty Changes in Software Patches

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29th acm Joint Meeting on European Software Engineering Conference and Symposium on the Foundations of Software Engineering (ESEC/FSE)

作者： Sejfia, Adriana Zhao, Yixue Medvidovi, Nenad Univ Southern Calif Los Angeles CA 90007 USA Univ Massachusetts Amherst MA 01003 USA

ISBN: (纸本)9781450385626

Noise in software patches impacts their understanding, analysis, and use for tasks such as change prediction. Although several approaches have been developed to identify noise in patches, this issue has persisted. An analysis of a dataset of security patches for the Tomcat web server, which we further expanded with security patches from five additional systems, uncovered several kinds of previously unreported noise which we call nonessential casualty changes. These are changes that themselves do not alter the logic of the program but are necessitated by other changes made in the patch. In this paper, we provide a comprehensive taxonomy of casualty changes. We then develop CASCADE, an automated technique for automatically identifying casualty changes. We evaluate CASCADE with several publicly available datasets of patches and tools that focus on them. Our results show that CASCADE is highly accurate, that the kinds of noise it identifies occur relatively commonly in patches, and that removing this noise improves upon the evaluation results of a previously published change-based approach.

关键词： Software Patches Change-based analysis Noise in Patches

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SafeDM: a Hardware Diversity Monitor for Redundant Execution on Non-lockstepped Cores

SafeDM: a Hardware Diversity Monitor for Redundant Execution...

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25th Design, Automation and Test in Europe Conference and Exhibition (DATE)

作者： Bas, Francisco Benedicte, Pedro Alcaide, Sergi Cabo, Guillem Mazzocchetti, Fabio Abella, Jaume Barcelona Supercomp Ctr BSC Barcelona Spain Univ Politecn Catalunya UPC Barcelona Spain

ISBN: (纸本)9783981926361

computing systems in the safety domain, such as those in avionics or space, require specific safety measures related to the criticality of the deployment. A problem these systems face is that of transient failures in hardware. A solution commonly used to tackle potential failures is to introduce redundancy in these systems, for example 2 cores that execute the same program at the same time. However, redundancy does not solve all potential failures, such as Common Cause Failures (CCF), where a single fault affects both cores identically (e.g. a voltage droop). If both redundant cores have identical state when the fault occurs, then there may be a CCF since the fault can affect both cores in the same way. To avoid CCF it is critical to know that there is diversity in the execution amongst the redundant cores. In this paper we introduce SafeDM, a hardware Diversity Monitor that quantifies the diversity of each redundant processor to guarantee that CCF will not go unnoticed, and without needing to deploy lockstepped cores. SafeDM computes data and instruction diversity separately, using different techniques appropriate for each case. We integrate SafeDM in a RISC-V FPGA space MPSoC from Cobham Gaisler where SafeDM is proven effective with a large benchmark suite, incurring low area and power overheads. Overall, SafeDM is an effective hardware solution to quantify diversity in cores performing redundant execution.

关键词： Electric potential Redundancy Aerospace electronics Hardware Safety Synchronization Transient analysis

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THE analysis of the EDUCATIONAL measurement RESULTS, and ITS PROVIDING AS "SOFTWARE-AS-A-SERVICE" SOLUTION in ELEARNING 9

THE ANALYSIS of the EDUCATIONAL MEASUREMENT RESULTS, and ITS...

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9th International Conference "Distributed computing and Grid Technologies in Science and Education", GRID 2021

作者： Lavdina, Yulia Gustun, Oleg Budaragin, Nikolay Leonova, Nataliya Modyaev, Alexey 31 Kashirskoe Shosse Moscow115409 Russia

In modern eLearning systems, educational measurements are used both to evaluate the students' achievements and to control the learning process. However, eLearning systems usually have comparatively trivial embedded features for analyzing measurement results, which are not of considerable interest for sufficient statistical research of the assessment tools quality. To identify the characteristics of assessment materials such as reliability, homogeneity, discriminatory power, validity, and others, researchers are forced to get dump from the database of eLearning system. And then they use third-party software to perform required data processing operations and calculations. This makes it difficult to analyze the measurement results during the measuring itself, for example, in adaptive testing. We propose the approach to organizing and performing measurement results analysis by using the software-as-a-service (SaaS) model for cloud computing. The SaaS user is provided with the set of necessary tools for conducting full-fledged statistical analysis in real time. They also get the access to customizable applications for implementing their own measurement procedures (including adaptive ones). Copyright © 2021 for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).

关键词： Statistical methods

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Micro-activity recognition in industrial assembly process with IMU data and deep learning 22

Micro-activity recognition in industrial assembly process wi...

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15th acm International Conference on Pervasive Technologies Related to Assistive Environments (PETRA)

作者： Sopidis, Georgios Haslgruebler, Michael Azadi, Behrooz Anzengruber-Tanase, Bernhard Ahmad, Abdelrahman Ferscha, Alois Baresch, Martin Pro2Future GmbH Linz Austria Keba GmbH Linz Linz Austria

ISBN: (纸本)9781450396318

Automated understanding of work-steps in industrial assembly work is important for assistive guidance technologies in employee-machine collaboration. Our aim is to identify micro activities of employees during the assembly of automated teller machines (ATM) for purposes of assistance in their daily complex tasks using mobile wearable devices and hand-operated tools. Forgotten or incorrectly installed parts, missing or non-tightened screws during assembly, that are expensive and time consuming to repair are some common mistakes that are addressed with this approach. In this paper the focus is at a seamless embedding of non-impeding Inertial measurement Units (IMUs), worn on body or integrated into tools and devices, allowing for unobstructed monitoring of tools' usage pattern. Therefore, understanding the activities that occurred and thus recognizing the assembly work steps. The hypothesis is that a system capable of high level detection for micro activities in an assembly line, utilizing IMUs and neural networks, will (i) reduce the error rate in the final product, (ii) assist the workers in real-time scenarios by performing quality control (iii) understand the stages of the assembly workflow. The results for this study are evidenced with empirical observations of work-step executions by (i) hand screwing, (ii) screw driver screwing, (iii) machine screwing, (iv) wrench screwing, with the size of null class being disproportionally dominant in the data set. Deep Learning models including Long Short-term Memory (LSTM) and Convolutional Neural Network (CNN) architectures are evaluated, while presenting the challenges encountered during our research and experiments. The classification performance for our experiments is documented and in the final step a recognition of 91.19% is achieved, using a CNN.

关键词： Mobile wearable computing cognitive systems human activity recognition modelling and reasoning deep learning industrial manufacturing

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SmoothMV: Seamless Content Adaptation through Head Tracking analysis and View Prediction 13

<i>SmoothMV</i>: Seamless Content Adaptation through Head Tr...

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13th acm International Workshop on Immersive Mixed and Virtual Environment systems (MMVE) Part of acm Multimedia systems Conference (MMSys)

作者： da Costa, Tiago Soares Andrade, Maria Teresa Viana, Paula INESC TEC Ctr Telecommun & Multimedia Porto Portugal Univ Porto INESC TEC Fac Engn Porto Portugal Polytech Porto INESC TEC Porto Sch Engn Porto Portugal

ISBN: (纸本)9781450384360

Multi-view has the potential to offer immersive viewing experiences to users, as an alternative to 360 degrees and Virtual Reality (VR) applications. In multi-view, a limited number of camera views are sent to the client and missing views are synthesised locally. Given the substantial complexity associated to view synthesis, considerable attention has been given to optimise the trade-off between bandwidth gains and computing resources, targeting smooth navigation and viewing quality. A still relatively unexplored field is the optimisation of the way navigation interactivity is achieved, i.e. how the user indicates to the system the selection of new viewpoints. In this article, we introduce SmoothMV, a multi-view system that uses a non-intrusive head tracking approach to enhance navigation and Quality of Experience (QoE) of the viewer. It relies on a novel Hot&Cold matrix concept to translate head positioning data into viewing angle selections. Streaming of selected views is done using MPEG-DASH, where a proposed extension to the standard descriptors enables to achieve consistent and flexible view identification.

关键词： Multi-view multimedia view prediction content adaptation user behaviour adaptive streaming

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Characterizing Microservice Dependency and Performance: Alibaba Trace analysis 12

Characterizing Microservice Dependency and Performance: Alib...

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12th Annual acm Symposium on Cloud computing (SoCC)

作者： Luo, Shutian Xu, Huanle Lu, Chengzhi Ye, Kejiang Xu, Guoyao Zhang, Liping Ding, Yu He, Jian Xu, Chengzhong Univ CAS CAS Shenzhen Inst Adv Technol Beijing Peoples R China Univ Macau Zhuhai Peoples R China Chinese Acad Sci Shenzhen Inst Adv Technol Beijing Peoples R China Alibaba Grp Hangzhou Peoples R China Guangdong Hong Kong Macao Joint Lab Human Machine Shenzhen Peoples R China

ISBN: (纸本)9781450386388

Loosely-coupled and light-weight microservices running in containers are replacing monolithic applications gradually. Understanding the characteristics of microservices is critical to make good use of microservice architectures. However, there is no comprehensive study about microservice and its related systems in production environments so far. In this paper, we present a solid analysis of large-scale deployments of microservices at Alibaba clusters. Our study focuses on the characterization of microservice dependency as well as its runtime performance. We conduct an in-depth anatomy of microservice call graphs to quantify the difference between them and traditional DAGs of data-parallel jobs. In particular, we observe that microservice call graphs are heavy-tail distributed and their topology is similar to a tree and moreover, many microservices are hot-spots. We reveal three types of meaningful call dependency that can be utilized to optimize microservice designs. Our investigation on microservice runtime performance indicates most microservices are much more sensitive to CPU interference than memory interference. To synthesize more representative microservice traces, we build a mathematical model to simulate call graphs. Experimental results demonstrate our model can well preserve those graph properties observed from Alibaba traces.

关键词： Trees (mathematics)

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Probing with Precision: Probing Question Generation for Architectural Information Elicitation

Probing with Precision: Probing Question Generation for Arch...

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Multi-disciplinary, Open, and RElevant Requirements Engineering (MO2RE), IEEE/acm Workshop on

作者： Gokul Rejithkumar Preethu Rose Anish Jyoti Shukla Smita Ghaisas TCS Research Pune India

ISBN: (数字)9798400705694

ISBN: (纸本)9798350364842

Software Requirements Specifications (SRS) often lack the necessary level of specificity required by software architects to make well-informed architectural decisions. This deficiency compels software architects to probe business analysts to collect more details pertinent to architectural requirements from the clients. In our previous work, we introduced Probing Question-flows (PQ-flows) that can assist business analysts to probe stakeholders and gather architecturally significant information for the creation of a more comprehensive SRS. Key limitations of our previous work were the manually created templatized PQ-flows and the mapping of PQ-flows to the software requirements based on standard Vector Space Model. In this study, we propose a Retrieval Augmented Generation (RAG) prompting framework to address these limitations. We conducted experiments using ChatGPT and Mistral-7B models. We present our findings utilizing human and automated evaluation metrics on a subset of the publicly available PUblic REquirements (PURE) *** CONCEPTS• Software and its engineering → Requirements analysis; • computing methodologies → Natural language generation; • Information systems → Information retrieval query processing; Question answering.

关键词： Barium Chatbots Software Vectors Time measurement Stakeholders Probes

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