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USENIX 1998 Annual Technical Conference

作者： Magnusson, Peter S. Dahlgren, Fredrik Grahn, Håkan Karlsson, Magnus Larsson, Fredrik Lundholm, Fredrik Moestedt, Andreas Nilsson, Jim Stenström, Per Werner, Bengt Swedish Institute of Computer Science Box 1263 KistaSE-164 28 Sweden Department of Computer Engineering Chalmers University of Technology GöteborgSE-412 96 Sweden Department of Computer Science University of Karlskrona/Ronneby RonnebySE-372 25 Sweden

System level simulators allow computer architects and system software designers to recreate an accurate and complete replica of the program behavior of a target system, regardless of the availability, existence, or instrumentation support of such a system. Applications include evaluation of architectural design alternatives as well as software engineering tasks such as traditional debugging and performance tuning. We present an implementation of a simulator acting as a virtual workstation fully compatible with the sun4m architecture from Sun Microsystems. Built using the system-level SPARC V8 simulator SimICS, SimICS/sun4m models one or more SPARC V8 processors, supports user-developed modules for data cache and instruction cache simulation and execution profiling of all code, and provides a symbolic and performance debugging environment for operating systems. SimICS/sun4m can boot unmodified operating systems, including Linux 2.0.30 and Solaris 2.6, directly from snapshots of disk partitions. To support essentially arbitrary code, we implemented binary-compatible simulators for several devices, including SCSI, console, interrupt, timers, EEPROM, and Ethernet. The Ethernet simulation hooks into the host and allows the virtual workstation to appear on the local network with full services available (NFS, NIS, rsh, etc). Ethernet and console traffic can be recorded for future playback. The performance of SimICS/sun4m is sufficient to run realistic workloads, such as the database benchmark TPC-D, scaling factor 1/100, or an interactive network application such as Mozilla. The slowdown in relation to native hardware is in the range of 25 to 75 (measured using SPECint95). We also demonstrate some applications, including modeling an 8-processor sun4m version (which does not exist), modeling future memory hierarchies, and debugging an operating system. © USENIX 1998 Annual Technical Conference. all rights reserved.

关键词： Ethernet

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Time-SWAD: A Dataflow Engine for Time-Based Single Window Stream Aggregation

Time-SWAD: A Dataflow Engine for Time-Based Single Window St...

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IEEE International Conference on Field-Programmable technology (FPT)

作者： Prajith Ramakrishnan Geethakumari Vincenzo Gulisano Pedro Trancoso Ioannis Sourdis Chalmers University of Technology Gothenburg Sweden Department of Computer Science and Engineering Chalmers University of Technology Gothenburg Sweden

High throughput and low latency streaming aggregation is essential for many applications that analyze massive volumes of data in real-time. Incoming data need to be stored in a single sliding window before processing, in cases where incremental aggregations are wasteful or not possible at all; this puts tremendous pressure to the memory bandwidth. In addition, particular problems call for time-based windows, defined by a time-interval, where the amount of data per window may vary and as a consequence are more challenging to handle. This paper describes Time-SWAD, the first accelerator for time-based single-window stream aggregation. Time-SWAD is a dataflow engine (DFE), implemented on a Maxeler machine, offering high processing throughput, up to 150 Mtuples/sec, similar to related GPU systems, which however do not support both time-based and single windows. It uses a direct feed of incoming data from the network and has direct access to off-chip DRAM, enabling ultra-low processing latency of 1-10 μsec, at least 4 orders of magnitude lower than software-based solutions.

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Phantom: Curating github for engineered software projects using time-series clustering

arXiv

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arXiv 2019年

作者： Pickerill, Peter Jungen, Heiko Joshua Ochodek, Miros law Staron, Miroslaw Department of Computer Science and Engineering Chalmers University of Technology Poznan University of Technology Chalmers University of Technology i University of Gothenburg

Context: Within the field of Mining Software Repositories, there are numerous methods employed to filter datasets in order to avoid analysing lowquality projects. Unfortunately, the existing filtering methods have not kept up with the growth of existing data sources, such as GitHub, and researchers often rely on quick and dirty techniques to curate datasets. Objective: The objective of this study is to develop a method capable of filtering large quantities of software projects in a time-efficient way. Method: This study follows the Design science Research (DSR) methodology. The proposed method, PHANTOM, extracts five measures from Git logs. Each measure is transformed into a time-series, which is represented as a feature vector for clustering using the k-means algorithm. Results: Using the ground truth from a previous study, PHANTOM was shown to be able to rediscover the ground truth with up to 0.87 Precision or 0.94 Recall, and be able to identify "well-engineered" projects with up to 0.87 Precision and 0.94 Recall on the validation dataset. PHANTOM downloaded and processed the metadata of 1,786,601 GitHub repositories in 21.5 days, which is over 33% faster than a similar study, which used a computer cluster of 200 nodes. Conclusions: It is possible to use an unsupervised approach to identify well-engineering projects. PHANTOM was shown to be competitive compared to the existing supervised approaches while reducing the hardware requirements by two orders of magnitude. Copyright © 2019, The Authors. All rights reserved.

关键词： K-means clustering

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Estimating Return on Investment for GUI Test Automation Frameworks

Estimating Return on Investment for GUI Test Automation Fram...

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International Symposium on Software Reliability engineering (ISSRE)

作者： Felix Dobslaw Robert Feldt David Michaëlsson Patrik Haar Francisco Gomes de Oliveira Neto Richard Torkar Dept. of Computer Science and Engineering Chalmers University of Technology Chalmers University of Technology Canea Partner Group University of Gothenburg Dept. of Computer Science and Engineering University of Gothenburg

Automated graphical user interface (GUI) tests can reduce manual testing activities and increase test frequency. This motivates the conversion of manual test cases into automated GUI tests. However, it is not clear whether such automation is cost-effective given that GUI automation scripts add to the code base and demand maintenance as a system evolves. In this paper, we introduce a method for estimating maintenance cost and Return on Investment (ROI) for Automated GUI Testing (AGT). The method utilizes the existing source code change history and has the potential to be used for the evaluation of other testing or quality assurance automation technologies. We evaluate the method for a real-world, industrial software system and compare two fundamentally different AGT frameworks, namely Selenium and EyeAutomate, to estimate and compare their ROI. We also report on their defect-finding capabilities and usability. The quantitative data is complemented by interviews with employees at the company the study has been conducted at. The method was successfully applied, and estimated maintenance cost and ROI for both frameworks are reported. Overall, the study supports earlier results showing that implementation time is the leading cost for introducing AGT. The findings further suggest that, while EyeAutomate tests are significantly faster to implement, Selenium tests require more of a programming background but less maintenance.

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Automated Optimization of Software Parameters in a Long Term Evolution Radio Base Station

Automated Optimization of Software Parameters in a Long Term...

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Annual IEEE International Systems Conference

作者： David Issa Mattos Jan Bosch Helena Holmstrom Olsson Anas Dakkak Krister Bergh Department of Computer Science and Engineering Chalmers University of Technology Department of Computer Science and Media Technology Malmo University Ericsson

ISBN: (纸本)9781538683972

Radio network optimization is concerned with the configuration of radio base station parameters in order to achieve the desired level of service quality in addition to many other differentiating technical factors. Mobile network operators have different physical locations, levels of traffic profiles, number of connected devices, and the desired quality of service. All of these conditions make the problem of optimizing the parameters of a radio base station specific to the operator's business goals. The high number of calibration parameters and the complex interaction between them make the system behave as a black-box model for any practical purpose. The computation of relevant operator metrics is often stochastic, and it can take several minutes to compute the effect of changing a single, making it impractical to optimize systems with approaches that require a large number of iterations. Operators want to optimize their already deployed system in online scenarios while minimizing the exposure of the system to a negative set of parameters during the optimization procedure. This paper presents a novel approach to the optimization of a Long Term Evolution (LTE) radio base station in a large search space with an expensive stochastic objective and a limited regret bounds scenario. We show the feasibility of this approach by implementing it in an industrial testing bed radio base station connected to real User Equipment (UE) in collaboration with Ericsson. Two optimization processes in this experimental setup are executed to show the feasibility of the approach in real-world scenarios.

关键词： Online experiments Expensive optimization Radio base station Testing bed

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Coordinated management of DVFS and cache partitioning under QoS constraints to save energy in multi-core systems

arXiv

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arXiv 2019年

作者： Nejat, Mehrzad Manivannan, Madhavan Pericàs, Miquel Stenström, Per Department of Computer Science & Engineering Chalmers University of Technology Gothenburg Sweden

Reducing the energy expended to carry out a computational task is important. In this work, we explore the prospects of meeting Quality-of-Service requirements of tasks on a multi-core system while adjusting resources to expend a minimum of energy. This paper considers, for the first time, a QoS-driven coordinated resource management algorithm (RMA) that dynamically adjusts the size of the per-core last-level cache partitions and the per-core voltage-frequency settings to save energy while respecting QoS requirements of every application in multi-programmed workloads run on multi-core systems. It does so by doing configuration-space exploration across the spectrum of LLC partition sizes and Dynamic Voltage Frequency Scaling (DVFS) settings at runtime at negligible overhead. We show that the energy of 4-core and 8-core systems can be reduced by up to 18% and 14%, respectively, compared to a baseline with even distribution of cache resources and a fixed mid-range core voltage-frequency setting. The energy savings can potentially reach 29% if the QoS targets are relaxed to 40% longer execution time. Copyright © 2019, The Authors. All rights reserved.

关键词： Dynamic frequency scaling

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Author Correction: AutoTransOP: translating omics signatures without orthologue requirements using deep learning

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NPJ systems biology and applications 2024年第1期10卷 148页

作者： Nikolaos Meimetis Krista M Pullen Daniel Y Zhu Avlant Nilsson Trong Nghia Hoang Sara Magliacane Douglas A Lauffenburger Department of Biological Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA. Department of Biology and Biological Engineering Chalmers University of Technology Gothenburg SE 41296 Sweden. School of Electrical Engineering and Computer Science Washington State University Pullman WA 99164-236 USA. Institute of Informatics University of Amsterdam Amsterdam The Netherlands. MIT-IBM Watson AI Lab Cambridge MA 02139 USA. Department of Biological Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA. lauffen@mit.edu.

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Transoceanic phase and polarization fiber sensing using real-time coherent transceiver

arXiv

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arXiv 2021年

作者： Mazur, Mikael Castellanos, Jorge C. Ryf, Roland Börjeson, Erik Chodkiewicz, Tracy Kamalov, Valey Yin, Shuang Fontaine, Nicolas K. Chen, Haoshuo Dallachiesa, Lauren Corteselli, Steve Copping, Philip Gripp, Jürgen Mortelette, Aurelien Kowalski, Benoit Dellinger, Rodney Neilson, David T. Larsson-Edefors, Per Nokia Bell Labs 600 Mountain Ave. Murray HillNJ07974 United States Google LLC Mountain ViewCA94043 United States Department of Computer Science and Engineering Chalmers University of Technology Sweden Nokia 600 Mountain Ave. Murray HillNJ07974 United States

We implement a real-time coherent transceiver with fast streaming outputs for environmental sensing. Continuous sensing using phase and equalizer outputs over 12800km of a submarine cable is demonstrated to enable time resolved spectroscopy in broad spectral range of 10mHz - 1kHz. Copyright © 2021, The Authors. All rights reserved.

关键词： Laser spectroscopy

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High-bandwidth spatial equalization for mmWave massive MU-MIMO with processing-in-memory

arXiv

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arXiv 2020年

作者： Castañeda, Oscar Jacobsson, Sven Durisi, Giuseppe Goldstein, Tom Studer, Christoph School of Electrical and Computer Engineering Cornell Tech New YorkNY United States Ericsson Research Gothenburg Sweden Chalmers University of Technology Gothenburg Sweden Department of Computer Science University of Maryland College ParkMD United States

All-digital basestation (BS) architectures enable superior spectral efficiency compared to hybrid solutions in massive multi-user MIMO systems. However, supporting large bandwidths with all-digital architectures at mmWave frequencies is challenging as traditional baseband processing would result in excessively high power consumption and large silicon area. The recently-proposed concept of finite-alphabet equalization is able to address both of these issues by using equalization matrices that contain low-resolution entries to lower the power and complexity of high-throughput matrix-vector products in hardware. In this paper, we explore two different finite-alphabet equalization hardware implementations that tightly integrate the memory and processing elements: (i) a parallel array of multiply-accumulate (MAC) units and (ii) a bit-serial processing-in-memory (PIM) architecture. Our all-digital VLSI implementation results in 28nm CMOS show that the bit-serial PIM architecture reduces the area and power consumption up to a factor of 2× and 3×, respectively, when compared to a parallel MAC array that operates at the same throughput. Copyright © 2020, The Authors. All rights reserved.

关键词： MIMO systems

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Infrastructure-based Multi-Camera Calibration using Radial Projections

arXiv

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arXiv 2020年

作者： Lin, Yukai Larsson, Viktor Geppert, Marcel Kukelova, Zuzana Pollefeys, Marc Sattler, Torsten Department of Computer Science ETH Zrich Switzerland VRG Faculty of Electrical Engineering Czech Technical University in Prague Czech Republic Microsoft Mixed Reality & AI Zurich Lab Department of Electrical Engineering Chalmers University of Technology Sweden

Multi-camera systems are an important sensor platform for intelligent systems such as self-driving cars. Pattern-based calibration techniques can be used to calibrate the intrinsics of the cameras individually. However, extrinsic calibration of systems with little to no visual overlap between the cameras is a challenge. Given the camera intrinsics, infrastucture-based calibration techniques are able to estimate the extrinsics using 3D maps pre-built via SLAM or Structure-from-Motion. In this paper, we propose to fully calibrate a multi-camera system from scratch using an infrastructure-based approach. Assuming that the distortion is mainly radial, we introduce a two-stage approach. We first estimate the camera-rig extrinsics up to a single unknown translation component per camera. Next, we solve for both the intrinsic parameters and the missing translation components. Extensive experiments on multiple indoor and outdoor scenes with multiple multi-camera systems show that our calibration method achieves high accuracy and robustness. In particular, our approach is more robust than the naive approach of first estimating intrinsic parameters and pose per camera before refining the extrinsic parameters of the system. The implementation is available at https://***/youkely/InfrasCal. Copyright © 2020, The Authors. All rights reserved.

关键词： Cameras

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