121,997 research outputs found
Efficient Mechanisms for the Supply of Services in Multi-Agent Environments
No full textAuctions provide an efficient way of resolving one-to-many negotiations. This is particularly true for automated agents where delays and long communications carry negative externalities. A properly designed auction, tailored to the specific needs of the relevant multi-agent system, can significantly improve its performance. In this paper, we focus on the specific problem of service allocation among autonomous, automated agents, within the context of the ADEPT project, which concerns the BT (British Telecom) business process of providing a quote for designing a network for a customer. The main contributions of this paper are threefold: First, we show how an English auction can be modified for services, which are multi-dimensional private value objects. Second, we show how, under certain conditions, auctions can be arranged by the service providing agents, in the cases where the service seeking agents fail to do so. We consider the incentives of all participants, and show how such an arrangement can be in their best interest. Finally, by examining our results for what is, essentially, an application of game-theory and mechanism design to an existing application, we draw some general conclusions on how such concepts can be operationalized in automated agents
Uncertainty and endogenous selection of economic equilibria
No full textThis paper presents a model of co-ordination failures based on market power and local oligopoly. The economy exhibits a multiplicity of Pareto-ranked equilibria. The introduction of uncertainty generates an endogenous equilibrium selection process, due to a strategic use of information by firms. The economy is more likely to settle on some equilibria than on others. We argue that a full understanding of these robustness criteria is needed before any policy which is intended to help co-ordinate the level of activity to a Pareto dominant outcome can be successfully implemented
Comparative performance analysis of vulkan implementations of computational applications
No full textThe recent introduction of the Vulkan API and the SPIR-V intermediate-level language by the Khronos Group provides a new GPU programming model in an effort to combine the advantages of its predecessors, OpenGL for 3D graphics and OpenCL for computing. Vulkan’s low-level and more direct control over the underlying GPU hardware as well as its support for explicit multi-threaded execution offers opportunities for better performance at the cost of higher programming effort. Most of the previous work associated with Vulkan has targeted the graphics pipeline. The fact that Vulkan also supports the compute pipeline has motivated us to examine it from the GPGPU perspective, by porting a number of realistic applications to a desktop GPU and evaluating their Vulkan implementations in terms of performance and programmability. Specifically, we consider the Laplacian filter which is used in image processing to detect areas of rapid change (edges) in images. Also, we consider a Visual Odometry (VO) application used to track the position and pose of a robot by analyzing a sequence of camera frames. VO is part of a Simultaneous Localization and Mapping (SLAM) application used in autonomous navigation systems to build a map of surrounding environments and to determine the location of a moving robot inside this map. These applications require advanced pixel-level processing at different levels of pyramid-based granularity, and may even require real-time performance (when, for example, SLAM is used in a robot navigation system). We ported the original implementations (written in C for Laplacian filter and in CUDA for SLAM) to OpenCL, OpenGL and Vulkan and evaluated their performance on a desktop NVIDIA GPGPU. We show that Vulkan performance is comparable (within 10%) with the performance attained by OpenCL and higher than the performance attained by OpenGL compute shader implementations. By exploiting Vulkan synchronization primitives using the command buffer, we can eliminate the overhead of launching multiple kernel invocations in iterative applications and improve performance of Vulkan implementations by up to 30%. However, the OpenCL compiler seems to be more mature than the SPIR-V compiler used in Vulkan implementations resulting in slightly faster OpenCL kernel execution. On the other hand, the low-level semantics of Vulkan demand higher programming effort compared with OpenCL/OpenGL which can be a burden if Vulkan is to be used as a GPGPU programming model. Most of the additional effort, however, is boilerplate code that can be reused in more than one Vulkan applications. Our work is one of the first to consider Vulkan compute as an implementation language for larger scale applications (and not just for small kernels as in previous work). © 2019 Copyright is held by the owner/author(s)
vkpolybench: A crossplatform Vulkan Compute port of the PolyBench/GPU benchmark suite
No full textPolyBench is a well-known set of benchmarks characterized by embarrassingly parallel kernels able to run on Graphic Processing Units (GPUs). While Polybench GPU kernels leverage well-established GP-GPU APIs such as CUDA and OpenCL, in this paper we present vkpolybench, a crossplatform PolyBench/GPU port built on top of Vulkan. Vulkan is the recently released Khronos standard for heterogeneous CPU–GPU computing that is gaining significant traction lately. Compared to CUDA and OpenCL, the Vulkan API improves GPU utilization while reducing CPU overheads
THE VULKAN TECHNIQUE: A NOVEL OSTOMY-CLOSURE TECHNIQUE THAT REDUCES COMPLICATIONS AND OPERATIVE TIMES
No full textABSTRACT Background: Ostomy reversals remain at high risk for surgical complications. Indeed, surgical-side infections due to bacterial contamination of the stoma lead to revision surgery and prolonged hospital stay. Aim: To describe the novel vulkan technique of ostomy reversal that aims to reduce operative times, surgical complications, and readmission rates. Methods: Ostomy closure was performed using the vulkan technique in all patients. This technique consists of external intestinal closure, circular skin incision and adhesiolysis, re-anastomosis, and closure of the subcutaneous tissue in three layers, while leaving a small secondary wound through which exudative fluid can be drained. The medical records of enterostomy patients were retrospectively reviewed from our hospital database. Results: The vulkan technique was successfully performed in 35 patients mainly by resident surgeons with <5 years of experience (n=22; 62.8%). The ileostomy and colostomy closure times were 53 min (interquartile range [IQR], 41-68 min; n=22) and 136 min (IQR: 88-188 min; n=13; p<0.001), respectively. The median hospital stay was seven days (IQR: 5−14.5 days); the length of hospital stay did not differ between ileostomy and colostomy groups. Major surgical complications occurred only in patients who underwent colostomy closure following the Hartmann procedure (n=2); grade≥IIIb according Clavien-Dindo classification. Conclusion: The vulkan technique was successfully applied in all patients with very low rates of surgical-site infections. Off note, residents with limited surgical experience mainly performed the procedure while operating time was less than one hour.</jats:p
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The vanishing author in computer-generated works: a critical analysis of recent Australian case law
No full textAbstract
The use of software is ubiquitous in the creation of many copyright works, yet the requirement in copyright law that every work have a human author who engages in independent intellectual effort means that its use may prevent copyright subsistence. Several recent Australian cases have refocused attention on authorship as an essential criterion of copyright subsistence, and these cases suggest that much computer-produced output may be authorless and thus lack copyright protection. This article, the first in a two-part series, analyses how each case deals with the question of authorship of computer-produced works and why the use of software diminishes copyright protection for a significant number of computer-generated works. The article critiques the application of conventional notions of human authorship developed in the pre-computer age to modern productions and suggests alternative approaches to authorship that satisfy both the major objectives of copyright policy and the need to adapt to the computer age. The article argues that, without a broader judicial approach to authorship of computer-generated works, Parliament must remedy the lacuna in protection for these ‘authorless’ works. Possible solutions for reform are suggested. In a forthcoming article, the author comprehensively examines those reform proposals
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
High-Performance Interactive Scientific Visualization With Datoviz via the Vulkan Low-Level GPU API
No full textWe reported initial work towards a new fast and scalable scientific visualization technology that leverages the Vulkan API to achieve unprecedented performance through GPUs. This technology is implemented in a C/C++ library called Datoviz that offers an intermediate-level API for scientific visualization libraries and software. Datoviz provides a unified graphics stack for 2-D, 3-D, graphical user interfaces, and natively supports efficient interactions between rendering and general-purpose GPU computing. A major direction of development is to investigate the integration of Datoviz as a low-level backend of a future version of VisPy, a popular Python scientific plotting librar
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