POWAR: Power-Aware Routing in HPC Networks with On/Off Links

[EN] In order to save energy in HPC interconnection networks, one usual proposal is to switch idle links into a low-power mode after a certain time without any transmission, as IEEE Energy Efficient Ethernet standard proposes. Extending the low-power mode mechanism, we propose POWer-Aware Routing (POWAR), a simple power-aware routing and selection function for fat-tree and torus networks. POWAR adapts the amount of network links that can be used, taking into account the network load, and obtaining great energy savings in the network (55%-65%) and the entire system (9%-10%) with negligible performance overhead.This work has been supported by the Spanish MINECO and European Commission (FEDER funds) under project TIN2015-66972-C5-1-R. Francisco J. Andujar has been partially funded by the Spanish MICINN and by the ERDF program of the European Union: PCAS Project (TIN2017-88614-R), CAPAP-H6 (TIN2016-81840-REDT), and Junta de Castilla y Leon FEDER Grant VA082P17 (PROPHET Project).Andújar-Muñoz, FJ.; Coll, S.; Alonso Díaz, M.; López Rodríguez, PJ.; Martínez-Rubio, J. (2019). POWAR: Power-Aware Routing in HPC Networks with On/Off Links. ACM Transactions on Architecture and Code Optimization. 15(4):1-22. https://doi.org/10.1145/3293445S122154Abts, D., Marty, M. R., Wells, P. M., Klausler, P., & Liu, H. (2010). Energy proportional datacenter networks. Proceedings of the 37th annual international symposium on Computer architecture - ISCA ’10. doi:10.1145/1815961.1816004Adiga, N. R., Blumrich, M. A., Chen, D., Coteus, P., Gara, A., Giampapa, M. E., … Vranas, P. (2005). Blue Gene/L torus interconnection network. IBM Journal of Research and Development, 49(2.3), 265-276. doi:10.1147/rd.492.0265M. Alonso S. Coll J. M. Martínez V. 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ACM Transactions on Computer Systems, 11(4), 319-352. doi:10.1145/161541.161736Andujar, F. J., Villar, J. A., Sanchez, J. L., Alfaro, F. J., & Escudero-Sahuquillo, J. (2015). VEF Traces: A Framework for Modelling MPI Traffic in Interconnection Network Simulators. 2015 IEEE International Conference on Cluster Computing. doi:10.1109/cluster.2015.141Barroso, L. A., & Hölzle, U. (2007). The Case for Energy-Proportional Computing. Computer, 40(12), 33-37. doi:10.1109/mc.2007.443Camacho, J., & Flich, J. (2011). HPC-Mesh: A Homogeneous Parallel Concentrated Mesh for Fault-Tolerance and Energy Savings. 2011 ACM/IEEE Seventh Symposium on Architectures for Networking and Communications Systems. doi:10.1109/ancs.2011.17Chen, D., Parker, J. J., Eisley, N. A., Heidelberger, P., Senger, R. M., Sugawara, Y., … Steinmacher-Burow, B. (2011). The IBM Blue Gene/Q interconnection network and message unit. 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An Engineering Approach. Morgan Kaufmann Publishers Inc. San Francisco CA.GALGO 2017. GALGO—Albacete Research Institute of Informatics Supercomputer Center homepage. Retrieved from http://www.i3a.uclm.es/galgo. GALGO 2017. GALGO—Albacete Research Institute of Informatics Supercomputer Center homepage. Retrieved from http://www.i3a.uclm.es/galgo.Greenberg, A., Hamilton, J., Maltz, D. A., & Patel, P. (2008). The cost of a cloud. ACM SIGCOMM Computer Communication Review, 39(1), 68-73. doi:10.1145/1496091.1496103HPCC {n.d.}. HPC Challenge Benchmark. Retrieved from http://icl.cs.utk.edu/hpcc/index.html. HPCC {n.d.}. HPC Challenge Benchmark. Retrieved from http://icl.cs.utk.edu/hpcc/index.html.Hluchyj, M. G., & Karol, M. J. (1988). Queueing in high-performance packet switching. IEEE Journal on Selected Areas in Communications, 6(9), 1587-1597. doi:10.1109/49.12886Koibuchi, M., Otsuka, T., Hiroki Matsutani, & Amano, H. (2009). 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An analysis of the Leap-Frog Discontinuous Galerkin method for Maxwell equations

In this paper, we explore the accuracy limits of a Finite-Element Time-Domain method applied to the Maxwell equations, based on a Discontinuous Galerkin scheme in space, and a Leap-Frog temporal integration. The dispersion and dissipation properties of the method are investigated, as well as the anisotropy of the errors. The results of this novel analysis are represented in a practical and comprehensible manner, useful for the application of the method, and for the understanding of the behavior of the errors in Discontinuous Gelerkin Time-Domain methods. A comparison with the Finite-Difference Time-Domain method, in terms of computational cost, is also includedThe work described in this paper and the research leading to these results has received funding from the European Community’s Seventh Framework Programme FP7/2007-2013, under grant agreement no 205294 (HIRF SE project), and from the Spanish National Projects TEC2010-20841-C04-04, CSD2008-00068, and the Junta de Andalucia Project P09-TIC-

Soundscape Evaluation of a Heritage Event in an Open Environment: The Water Tribunal of the Plain of Valencia (Spain)

[EN] The acoustic evaluation of indoor environments is common in the application of virtual acoustics. In addition, in the study of cultural heritage buildings, it is a useful tool, but it is not so common when describing the acoustic environment in intangible cultural heritage events and even in outdoor environments. In this paper, the acoustic environment of the Water Tribunal of the Plain of Valencia (Spain) is studied. It is analyzed from a soundscape perspective, characterizing the sound source and evaluating it within relation to the environment and evaluating its subjective response. With the research carried out, it has been obtained, on the one hand, a complete study of the acoustics of the environment of the Water Tribunal and, on the other, an enhancement of the Valencian tangible and intangible heritage.This research was partially funded by Spanish Ministry of Science, Innovation and Universities, grant number BIA2016-76957-C3-3-R and by the Universitat de Valencia with the grant UV-INV-AE-1550319.Díaz-Rubio, E.; Segura-Garcia, J.; Fayos-Jordan, R.; Cerdá, S.; Cibrián, RM.; Giménez Pérez, A. (2022). Soundscape Evaluation of a Heritage Event in an Open Environment: The Water Tribunal of the Plain of Valencia (Spain). Applied Sciences. 12(9):1-17. https://doi.org/10.3390/app1209429211712

Consistency of expert product reviews: an application to wine guides

Purpose. The purpose of this study is to examine the internal consistency of wine guides by comparing the judgements of experts who taste and review wines. It further classifies the wines into categories to establish whether expert reviews of similar wines are coherent. Design/methodology/approach. Sentiment analysis based on natural language processing techniques was used to compare quantitative and qualitative reviews between experts. In addition, a finite mixture model was used to classify wines into categories to analyse internal consistency between ratings. Findings. The results for a sample of more than 200,000 Wine Enthusiast ratings reveal significant differences between the experts’ reviews, which shows that there are no standard criteria for reviewing the wines included in the guide. Originality. Wine guides are amongst the most widely used marketing resources in the wine industry. They provide a signal to consumers about the quality of wines, guiding their purchase decisions, whilst also influencing the reputation of brands and the performance of the companies producing these wines. Thus, the main contribution of this study is to improve comparisons of the assessments by wine guide experts in relation to the wines they taste. This analysis will make it possible to verify their effectiveness as a source of information for consumers and will allow wine producers to make more accurate assessments of the potential impact of experts on their performance

Efficient antenna modeling by DGTD

The work described in this article is partially funded by the Spanish National Projects TEC2013-48414-C3-01, CSD2008-00068, P09-TIC-5327, and P12-TIC-1442 and by the GENIL Excellence Network

A New efficient and stable 3D Conformal FDTD

A novel conformal technique for the FDTD method, here referred to as Conformal Relaxed Dey-Mittra method, is proposed and assessed in this letter. This technique helps avoid local time-step restrictions caused by irregular cells, thereby im- proving the global stability criterion of the original Dey-Mittra method. The approach retains a second-order spatial convergence. A numerical experiment based on the NASA almond has been chosen to show the improvement in accuracy and computational performance of the proposed method.The work described in this letter and the research leading to these results has received support from the Projects TEC2013- 48414-C3-01 and TEC2015-68766-REDC (MINECO, Spain), P12-TIC-1442 (Junta de Andalucia, Spain), Alhambra-UGRFDTD (AIRBUS DS), and by the CSIRC alhambra.ugr.es supercomputing center

Energy efficient torus networks with on/off links

[EN] Future exascale computing systems will require energy and performance efficient interconnection networks to respond to the high data movement demands of new applications, such as those coming from big-data and artificial intelligence areas. The network structure plays a major role in the overall interconnect performance, for this reason torus is a common topology used in the current largest supercomputers. There are several proposals to improve energy efficiency of interconnection networks. However, few works combine both energy and performance, and sometimes they are treated as opposed issues. In this paper, we try to determine which torus network configuration offers the best performance/energy ratio when high-radix switches are used to build the interconnect system. The performance/energy evaluation has been performed by trace-driven simulation under realistic scenarios, where several mixes of scientific applications share a supercomputer system and are scheduled to be executed with the available resources at each moment.This work has been supported by the Spanish MINECO and European Commission (FEDER funds) under project TIN2015-66972-05-1-R and project TIN2015-66972-05-2-R. Francisco J. Andujar is also funded by the Spanish MINECO under a Juan de la Cierva grant FJCI-2015-26080.Andújar, FJ.; Coll, S.; Alonso Díaz, M.; Martínez-Rubio, J.; López Rodríguez, PJ.; Sánchez, JL.; Alfaro, FJ.... (2019). Energy efficient torus networks with on/off links. Journal of Parallel and Distributed Computing. 130:37-49. https://doi.org/10.1016/j.jpdc.2019.03.015S374913

Energy efficient HPC network topologies with on/off links

[EN] Energy efficiency is a must in today HPC systems. To achieve this goal, a holistic design based on the use of power-aware components should be performed. One of the key components of an HPC system is the high-speed interconnect. In this paper, we compare and evaluate several design options for the interconnection network of an HPC system, including torus, fat-trees and dragonflies. State of the art low power modes are also used in the interconnection networks. The paper does not only consider energy efficiency at the interconnection network level but also at the system as a whole.The analysis is performed by using a simple yet realistic power model of the system. The model has been adjusted using actual power consumption values measured on a real system. Using this model, realistic multi-job trace-based workloads have been used, obtaining the execution time and energy consumed. The results are presented to ease choosing a system, depending on which parameter, performance or energy consumption, receives the most importance.This work has been supported by the Spanish Ministerio de Ciencia e Innovacion (MICINN, formerly MINECO) , and the European Commission (FEDER funds) under the projects PID2019- 105903RB-100 and PID2021-123627OB-C5, and by Junta de Comunidades de Castilla -La Mancha under the project SBPLY/21/180501/000248.Andújar-Muñoz, FJ.; Coll, S.; Alonso Díaz, M.; Martínez-Rubio, J.; López Rodríguez, PJ.; Sánchez García, JL.; Alfaro Cortés, FJ. (2023). Energy efficient HPC network topologies with on/off links. Future Generation Computer Systems. 139:126-138. https://doi.org/10.1016/j.future.2022.09.01212613813

Radial Photonic Crystal for detection of frequency and position of radiation sources

Based on the concepts of artificially microstructured materials, i.e. metamaterials, we present here the first practical realization of a radial wave crystal. This type of device was introduced as a theoretical proposal in the field of acoustics, and can be briefly defined as a structured medium with radial symmetry, where the constitutive parameters are invariant under radial geometrical translations. Our practical demonstration is realized in the electromagnetic microwave spectrum, because of the equivalence between the wave problems in both fields. A device has been designed, fabricated and experimentally characterized. It is able to perform beam shaping of punctual wave sources, and also to sense position and frequency of external radiators. Owing to the flexibility offered by the design concept, other possible applications are discussed.This work was supported in part by the Spanish Ministry of Science and Innovation under Grants TEC 2010-19751 and CSD2008-00066 (Consolider program) and by the U.S. Office of Naval Research under Grant N000140910554.Carbonell Olivares, J.; Díaz Rubio, A.; Torrent Martí, D.; Cervera Moreno, FS.; Kirleis, MA.; Pique, A.; Sánchez-Dehesa Moreno-Cid, J. (2012). Radial Photonic Crystal for detection of frequency and position of radiation sources. Scientific Reports. 2(558):1-8. https://doi.org/10.1038/srep00558S182558Pendry, J., Schurig, D. & Smith, D. Controlling electromagnetic fields. Science 312, 1780–1782 (2006).Leonhardt, U. Optical conformal mapping. Science 312, 1777–1780 (2006).Smith, D., Padilla, W., Vier, D., Nemat-Nasser, S. & Schultz, S. Composite medium with simultaneously negative permeability and permittivity. Phys. Rev. Lett. 84, 4184–4187 (2000).Pendry, J. B. Negative refraction makes a perfect lens. Phys. Rev. Lett. 85, 3966–3969 (2000).Schurig, D. et al. Metamaterial electromagnetic cloak at microwave frequencies. Science 314, 977–980 (2006).Narimanov, E. E. & Kildishev, A. V. Optical black hole: Broadband omnidirectional light absorber. Appl. Phys. Lett. 95, 041106 (2009).Grbic, A. & Eleftheriades, G. Overcoming the diffraction limit with a planar left-handed transmission-line lens. Phys. Rev. Lett. 92, 117403 (2004).Ma, H. F. & Cui, T. J. Three-dimensional broadband ground-plane cloak made of metamaterials. Nature Communications 1, 21 (2010).Engheta, N., Salandrino, A. & Alu, A. Circuit elements at optical frequencies: Nanoinductors, nanocapacitors and nanoresistors. Phys. Rev. Lett. 95, 095504 (2005).Zhang, F. et al. Negative-Zero-Positive Refractive Index in a Prism-Like Omega-Type Metamaterial. IEEE Trans. Microwave Theory Tech. 56, 2566–2573 (2008).Baena, J., Marques, R., Medina, F. & Martel, J. Artificial magnetic metamaterial design by using spiral resonators. Phys. Rev. B 69, 014402 (2004).Carbonell, J., Torrent, D., Diaz-Rubio, A. & Sanchez-Dehesa, J. Multidisciplinary approach to cylindrical anisotropic metamaterials. New J. Phys. 13, 103034 (2011).Torrent, D. & Sanchez-Dehesa, J. Radial Wave Crystals: Radially Periodic Structures from Anisotropic Metamaterials for Engineering Acoustic or Electromagnetic Waves. Phys. Rev. Lett. 103, 064301 (2009).Torrent, D. & Sanchez-Dehesa, J. Acoustic resonances in two-dimensional radial sonic crystal shells. New J. Phys. 12, 073034 (2010).Kurs, A. et al. Wireless power transfer via strongly coupled magnetic resonances. Science 317, 83–86 (2007).Marques, R., Medina, F. & Rafii-El-Idrissi, R. Role of bianisotropy in negative permeability and left-handed metamaterials. Phys. Rev. B 65, 144440 (2002).Pendry, J. B., Holden, A. J., Robbins, D. J. & Stewart, W. J. Magnetism from conductors and enhanced nonlinear phenomena. IEEE Trans. Microwave Theory Tech. 47, 2075–2084 (1999).Pollock, J. G. & Iyer, A. K. Effective-Medium Properties of Cylindrical Transmission-Line Metamaterials. IEEE Antennas and Wireless Propagation Letters 10, 1491–1494 (2011).Comsol, A. B. (Sweden). Comsol Multiphysics (v. 4.1). (2010).Ansoft. High Frequency Structure Simulator (HFSS), v.14. (2012).Smith, D. R., Vier, D. C., Koschny, T. & Soukoulis, C. M. Electromagnetic parameter retrieval from inhomogeneous metamaterials. Phys. Rev. E 71, 036617 (2005).Yang, Y. et al. Optofluidic waveguide as a transformation optics device for lightwave bending and manipulation. Nature Communications 3, 651 (2012).Liu, R. et al. Broadband Ground-Plane Cloak. Science 323, 366–369 (2009).Cheng, Q., Cui, T. J., Jiang, W. X. & Cai, B. G. An omnidirectional electromagnetic absorber made of metamaterials. New J. Phys. 12, 063006 (2010)