| 1. |
- Nguyen, Dang Nhan, 1983, et al.
(författare)
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Brief Announcement: ParMarkSplit: A Parallel Mark-Split Garbage Collector Based on a Lock-Free Skip-List
- 2013
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Ingår i: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - : Springer. - 1611-3349 .- 0302-9743. - 9783642415265 ; 8205, s. 557-558
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Konferensbidrag (refereegranskat)abstract
- This brief announcement provides a high level overview of a parallel mark-split garbage collector. Our parallel design introduces and makes use of an efficient concurrency control mechanism based on a lock-free skip-list design for handling the list of free memory intervals. We have implemented the parallel mark-split garbage collector in OpenJDK HotSpot as a parallel and concurrent garbage collector for the old generation. We experimentally evaluate the collector and compare it with the default concurrent mark-sweep garbage collector in OpenJDK HotSpot, using the DaCapo benchmarks.
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| 2. |
- Nguyen, Dang Nhan, 1983, et al.
(författare)
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ParMarkSplit : A Parallel Mark-Split Garbage Collector Based on a Lock-Free Skip-List
- 2014
-
Ingår i: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - Cham : Springer. - 1611-3349 .- 0302-9743. - 9783319144719 - 9783319144726 ; 8878, s. 372-387
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Konferensbidrag (refereegranskat)abstract
- Mark-split is a garbage collection algorithm that combines advantages of both the mark-sweep and the copying collection algorithms. In this paper, we present a parallel mark-split garbage collector (GC). Our parallel design introduces and makes use of an efficient concurrency control mechanism for handling the list of free memory intervals. This mechanism is based on a lock-free skip-list design which supports an extended set of operations. Beside basic operations, it can perform a composite one that can search and remove and also insert two elements atomically. We have implemented the parallel mark-split GC in OpenJDK’s HotSpot virtual machine. We experimentally evaluate our collector and compare it with the default concurrent mark-sweep GC in HotSpot, using the DaCapo benchmarks, on two contemporary multiprocessor systems; one has 12 Intel Nehalem cores with HyperThreading and the other has 48 AMD Bulldozer cores. The evaluation shows that our parallel mark-split keeps the characteristics of the sequential mark-split, that it performs better than the concurrent mark-sweep in applications that have low live/garbage ratio, and have live objects locating contiguously, therefore being marked consecutively. Our parallel mark-split performs significantly better than a trivial parallelization based on locks in terms of both collection time and scalability.
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| 3. |
- Sintorn, Erik, 1980, et al.
(författare)
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An efficient alias-free shadow algorithm for opaque and transparent objects using per-triangle shadow volumes
- 2011
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Ingår i: Proceedings of the 2011 SIGGRAPH Asia Conference, SA'11. - : Association for Computing Machinery (ACM). - 9781450308076 ; 30:6, s. 1-10
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Konferensbidrag (refereegranskat)abstract
- This paper presents a novel method for generating pixel-accurate shadows from point light-sources in real-time. The new method is able to quickly cull pixels that are not in shadow and to trivially accept large chunks of pixels thanks mainly to using the whole triangle shadow volume as a primitive, instead of rendering the shadow quads independently as in the classic Shadow-Volume algorithm. Our CUDA implementation outperforms z-fail consistently and surpasses z-pass at high resolutions, although these latter two are hardware accelerated, while inheriting none of the robustness issues associated with these methods. Another, perhaps even more important property of our algorithm, is that it requires no pre-processing or identification of silhouette edges and so robustly and efficiently handles arbitrary triangle soups. In terms of view sample test and set operations performed, we show that our algorithm can be an order of magnitude more efficient than z-pass when rendering a game-scene at multi-sampled HD resolutions. We go on to show that the algorithm can be trivially modified to support textured, semitransparent and colored semi-transparent shadow-casters and that it can be combined with either depth-peeling or stochastic transparency to also support transparent shadow receivers. Compared to recent alias-free shadow-map algorithms, our method has a very small memory footprint, does not suffer from load-balancing issues, and handles omni-directional lights without modification. It is easily incorporated into any deferred rendering pipeline and combines many of the strengths of shadow maps and shadow volumes.
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| 4. |
- Yu, Kan, et al.
(författare)
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REALFLOW : Reliable Real-Time Flooding-Based Routing Protocol for Industrial Wireless Sensor Networks
- 2014
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Ingår i: International Journal of Distributed Sensor Networks. - : SAGE Publications. - 1550-1329 .- 1550-1477. ; , s. art. nbr: 936379-
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Tidskriftsartikel (refereegranskat)abstract
- Wireless technologies have been increasingly applied in industrial automation systems due to flexible installation, mobility, and cost reduction. Unlike traditional wireless sensor networks (WSNs), industrial wireless sensor networks (IWSNs), when expanding from wireless monitoring to wireless control, have more stringent requirements on reliability, real-time performance, and robustness in a number of industrial applications. Successive transmission failures or deadline misses in these applications may severely degrade the control quality and result in serious economic losses and safety problems. Therefore, when deploying IWSNs in harsh industrial environments, to achieve reliable and deterministic end-to-end transmissions is critically important. In this paper, we explain the primary challenges of designing appropriate routing protocols and present a reliable real-time flooding-based routing protocol for IWSNs (REALFLOW). Instead of traditional routing tables, related node lists are generated in a simple distributed manner, serving for packet forwarding. A controlled flooding mechanism is applied to improve both reliability and real-time performance. A seamless transition in the event of topology change can be achieved by REALFLOW. Performance evaluations via simulations verify that significant improvements of reliability, real-time performance, and network recovery time can be achieved by REALFLOW, compared with traditional routing protocols.
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| 5. |
- Bello, Luciano, 1981, et al.
(författare)
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Towards a Taint Mode for Cloud Computing Web Application
- 2012
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Ingår i: 7th Workshop on Programming Languages and Analysis for Security. - New York, NY, USA : ACM. - 9781450314411 ; , s. 7:1--7:12-
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Konferensbidrag (refereegranskat)abstract
- Cloud computing is generally understood as the distribution of data and computations over the Internet. Over the past years, there has been a steep increase in web sites using this technology. Unfortunately, those web sites are not exempted from injection flaws and cross-site scripting, two of the most common security risks in web applications. Taint analysis is an automatic approach to detect vulnerabilities. Cloud computing platforms possess several features that, while facilitating the development of web applications, make it difficult to apply off-the-shelf taint analysis techniques. More specifically, several of the existing taint analysis techniques do not deal with persistent storage (e.g. object datastores), opaque objects (objects whose implementation cannot be accessed and thus tracking tainted data becomes a challenge), or a rich set of security policies (e.g. forcing a specific order of sanitizers to be applied). We propose a taint analysis for could computing web applications that consider these aspects. Rather than modifying interpreters or compilers, we provide taint analysis via a Python library for the cloud computing platform Google App Engine (GAE). To evaluate the use of our library, we harden an existing GAE web application against cross-site scripting attacks.
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| 6. |
- Bosch, Jan, 1967
(författare)
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Continuous Software Engineering: An Introduction
- 2014
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Ingår i: Continuous Software Engineering. - Cham : Springer International Publishing. ; , s. 3-13
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Software-intensive industries are experiencing an unprecedented evolution of, among others, business models, architectures, ways of working, tooling, and deployment. This transformation allows companies to respond much quicker to changes in the market and to build solutions that much more accurately align with customer needs. The Nordic software-intensive systems industry recognized this challenge and partnered with academia to form the Software Center. The role of the Software Center is to significantly accelerate the rate of adoption of these new approaches at the partner organizations. In this chapter, we discuss the industry trends, introduce the Software Center, and provide an overview of the remainder of the book. This book presents the core results of the first phase (2011–2013) of the Software Center.
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| 7. |
- Laskowski, Kornel, 1972-, et al.
(författare)
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On the dynamics of overlap in multi-party conversation
- 2012
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Ingår i: INTERSPEECH 2012. - Portland, USA : Curran Associates, Inc. - 9781622767595 ; , s. 846-849
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Konferensbidrag (refereegranskat)abstract
- Overlap, although short in duration, occurs frequently in multi- party conversation. We show that its duration is approximately log-normal, and inversely proportional to the number of simul- taneously speaking parties. Using a simple model, we demon- strate that simultaneous talk tends to end simultaneously less frequently than in begins simultaneously, leading to an arrow of time in chronograms constructed from speech activity alone. The asymmetry is significant and discriminative. It appears to be due to dialog acts which do not carry propositional content, and those which are not brought to completion.
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| 8. |
- Roupé, Mattias, 1975, et al.
(författare)
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3D-City Modeling: A Semi-automatic Framework for Integrating Different Terrain Models
- 2011
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Ingår i: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - 1611-3349 .- 0302-9743. - 9783642240300 ; Volume 6939/2011, s. 725-734
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Konferensbidrag (refereegranskat)abstract
- In recent years, many systems have been developed to handle realtime rendering of a 3D-city model and its terrain. These terrains are often constructed using one of the two main methods for representing terrain e.g. Image-based or geometry-based terrains. Both of these methods have its advantages and disadvantages, which are presented in this paper. However, by combining these methods and their advantages a more efficient modeling tool can be achieved. This paper presents a framework of how these two techniques can be linked and integrated by usage of the Graphics Processing Unit(GPU), which result in a user-friendlier and more efficient modeling process of terrain. The main objective with our framework is to address the difficulty of integrating a 3D model of a planned building with its surrounding ground, into a 3D-city model. Furthermore, the framework is also applicable on general3D models that address the same issues regarding integration of 3D models into a terrain model.
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| 9. |
- Svensson, Joel Bo, 1979, et al.
(författare)
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GPGPU Kernel Implementation and Refinement using Obsidian
- 2010
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Ingår i: ICCS 2010 conference proceedings; Amsterdam, NETHERLANDS, MAY 31-JUN 02, 2010. - : Elsevier BV. - 1877-0509. ; 1:1, s. 2059-2068
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Konferensbidrag (refereegranskat)abstract
- Obsidian is a domain specific language for data-parallel programming on graphics processors (GPUs). It is em-bedded in the functional programming language Haskell. The user writes code using constructs familiar from Haskell(like map and reduce), recursion and some specially designed combinators for combining GPU programs. NVIDIACUDA code is generated from these high level descriptions, and passed to the nvcc compiler [1]. Currently, weconsider only the generation of single kernels, and not their coordination.This paper is focussed on how the user should work with Obsidian, starting with an obviously correct (or well-tested) description of the required function, and refining it by the introduction of constructs to give finer control of thecomputation on the GPU. For some combinators, this approach results in CUDA code with satisfactory performance,promising increased productivity, as the high level descriptions are short and uncluttered. But for other combinators,the performance of generated code is not yet satisfactory. Ways to tackle this problem and plans to integrate Obsidianwith another higher-level embedded language for GPU programming in Haskell are briefly discussed.
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| 10. |
- Zeadally, Sherali, et al.
(författare)
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Vehicular ad hoc networks (VANETS) : status, results, and challenges
- 2012
-
Ingår i: Telecommunications Systems. - : Springer. - 1018-4864 .- 1572-9451. ; 50:4, s. 217-241
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in hardware, software, and communication technologies are enabling the design and implementation of a whole range of different types of networks that are being deployed in various environments. One such network that has received a lot of interest in the last couple of years is the Vehicular Ad-Hoc Network (VANET). VANET has become an active area of research, standardization, and development because it has tremendous potential to improve vehicle and road safety, traffic efficiency, and convenience as well as comfort to both drivers and passengers. Recent research efforts have placed a strong emphasis on novel VANET design architectures and implementations. A lot of VANET research work have focused on specific areas including routing, broadcasting, Quality of Service (QoS), and security. We survey some of the recent research results in these areas. We present a review of wireless access standards for VANETs, and describe some of the recent VANET trials and deployments in the US, Japan, and the European Union. In addition, we also briefly present some of the simulators currently available to VANET researchers for VANET simulations and we assess their benefits and limitations. Finally, we outline some of the VANET research challenges that still need to be addressed to enable the ubiquitous deployment and widespead adoption of scalable, reliable, robust, and secure VANET architectures, protocols, technologies, and services.
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