Some Bipartite States do not Arise from Channels

It is well-known that the action of a quantum channel on a state can be represented, using an auxiliary space, as the partial trace of an associated bipartite state. Recently, it was observed that for the bipartite state associated with the optimal average input of the channel, the entanglement of formation is simply the entropy of the reduced density matrix minus the Holevo capacity. It is natural to ask if every bipartite state can be associated with some channel in this way. We show that the answer is negative.Comment: 7 pages; minor typos corrected. To appear in special issue of the IBM Journal of Research and Development for Charles Bennett's 60th birthda

A cost-effective heuristic to schedule local and remote memory in cluster computers

Cluster computers represent a cost-effective alternative solution to supercomputers. In these systems, it is common to constrain the memory address space of a given processor to the local motherboard. Constraining the system in this way is much cheaper than using a full-fledged shared memory implementation among motherboards. However, memory usage among motherboards can be unfairly balanced. On the other hand, remote memory access (RMA) hardware provides fast interconnects among the motherboards of a cluster. RMA devices can be used to access remote RAM memory from a local motherboard. This work focuses on this capability in order to achieve a better global use of the total RAM memory in the system. More precisely, the address space of local applications is extended to remote motherboards and is used to access remote RAM memory. This paper presents an ideal memory scheduling algorithm and proposes a cost-effective heuristic to allocate local and remote memory among local applications. Compared to the devised ideal algorithm, the heuristic obtains the same (or closely resembling) results while largely reducing the computational cost. In addition, we analyze the impact on the performance of stand alone applications varying the memory distribution among regions (local, local to board, and remote). Then, this study is extended to any number of concurrent applications. Experimental results show that a QoS parameter is needed in order to avoid unacceptable performance degradation. © 2011 Springer Science+Business Media, LLC.This work was supported by Spanish CICYT under Grant TIN2009-14475-C04-01 and by Consolider-Ingenio under Grant CSD2006-00046.Serrano Gómez, M.; Sahuquillo Borrás, J.; Petit Martí, SV.; Hassan Mohamed, H.; Duato Marín, JF. (2012). A cost-effective heuristic to schedule local and remote memory in cluster computers. Journal of Supercomputing. 59(3):1533-1551. https://doi.org/10.1007/s11227-011-0566-8S15331551593IBM journal of Research and Development staff (2008) Overview of the IBM blue gene/P project. IBM J Res Dev 52(1/2):199–220Blocksome M, Archer C, Inglett T, McCarthy P, Mundy M, Ratterman J, Sidelnik A, Smith B, Almási G, Castaños J, Lieber D, Moreira J, Krishnamoorthy S, Tipparaju V, Nieplocha J (2006) Design and implementation of a one-sided communication interface for the IBM eServer Blue Gene® supercomputer. In: Proceedings of the 2006 ACM/IEEE conference on supercomputing, SC ’06, Tampa, FL, USA, November 2006, pp 54–54Kumar S, Dózsa G, Almasi G, Heidelberger P, Chen D, Giampapa M, Blocksome M, Faraj A, Parker J, Ratterman J, Smith BE, Archer C (2008) The deep computing messaging framework: generalized scalable message passing on the blue gene/P supercomputer. In: Proceedings of the 22nd annual international conference on supercomputing, Island of Kos, Greece, June 2008, pp 94–103Tipparaju V, Kot A, Nieplocha J, Bruggencate MT, Chrisochoides N (2007) Evaluation of remote memory access communication on the cray XT3. In: Proceedings of the 21th international parallel and distributed processing symposium, Long Beach, California, USA, March 2007, pp 1–7Nussle M, Scherer M, Bruning U (2009) A resource optimized remote-memory-access architecture for low-latency communication. In: International conference on parallel processing, Sept 2009, pp 220–227http://www.hypertransport.org/Serrano M, Sahuquillo J, Hassan H, Petit S, Duato J (2010) A scheduling heuristic to handle local and remote memory in cluster computers. In: Proceedings of the 12th IEEE international conference on high performance computing, Melbourne, Australia, Sept 2010, pp 35–42Keltcher CN, McGrath KJ, Ahmed A, Conway P (2003) The AMD opteron processor for multiprocessor servers. IEEE MICRO 23(2):66–76Duato J, Silla F, Yalamanchili S (2009) Extending hypertransport protocol for improved scalability. In: First international workshop on hypertransport research and applications.Litz H, Fröening H, Nuessle M, Brüening U (2007) A hypertransport network interface controller for ultra-low latency message transfers. HyperTransport Consortium White Paperhttps://www.simics.net/http://www.cs.wisc.edu/gems/http://www.cs.virginia.edu/stream/Woo SC, Ohara M, Torrie E, Singh JP, Gupta A (1995) The SPLASH-2 programs: Characterization and methodological considerations. In: Proceedings of the 22nd annual international symposium on computer architecture, New York, NY, USA, 1995, pp 24–36Levitin A (2003) Introduction to the design and analysis of algorithms. Addison Wesley, ReadingOleszkiewicz J, Xiao L, Liu Y (2004) Parallel network RAM: Effectively utilizing global cluster memory for large data-intensive parallel programs. In: Proceedings of 33rd international conference on parallel processing, Montreal, Quebec, Canada, pp 353–360Liang S, Noronha R, Panda DK (2005) Swapping to remote memory over infiniband: An approach using a high performance network block device. In: Proceedings of the 2005 IEEE international conference on cluster computing, Boston, Massachusetts, USA, pp 1–10Oguchi M, Kitsuregawa M (2000) Using available remote memory dynamically for parallel data mining application on ATM-connected PC cluster. In: Proceedings of the 14th international parallel & distributed processing symposium, Cancun, Mexico, pp 411–420Werstein P, Jia X, Huang Z (2007) A remote memory swapping system for cluster computers. In: Proceedings of the eighth international conference on parallel and distributed computing, applications and technologies, Adelaide, Australia, pp 75–81Midorikawa H, Kurokawa M, Himeno R, Sato M (2008) DLM: A distributed large memory system using remote memory swapping over cluster nodes. 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The Effect of Jetting Parameters on the Performance of Droplet Formation for Ink-Jet Rapid Prototyping

Heinzl et al. (1985) reports that experiments in ink-jets to produce drawings or signals occurred as early as 1930. Various companies such as IBM and Pitney-Bowes have conducted extensive studies on these devices for many years. Many such reports are available in such journals as the IBM Journal of Research and Development. While numerous articles have been published on the jetting characteristics of ink and water, the literature is rather limited on fluids such as waxes (Gao & Sonin 1994) or non-water based fluids (Passow, et al. 1993). This present study extends the knowledge base to determine the performance of molten waxes in "ink-jet" type printers for rapid prototyping. The purpose of this research was to qualitatively and quantitatively study the droplet formation of a drop-on-demand ink-jet type nozzle system for rapid prototyping

A new degree of freedom for memory allocation in clusters

Improvements in parallel computing hardware usually involve increments in the number of available resources for a given application such as the number of computing cores and the amount of memory. In the case of shared-memory computers, the increase in computing resources and available memory is usually constrained by the coherency protocol, whose overhead rises with system size, limiting the scalability of the final system. In this paper we propose an efficient and cost-effective way to increase the memory available for a given application by leveraging free memory in other computers in the cluster. Our proposal is based on the observation that many applications benefit from having more memory resources but do not require more computing cores, thus reducing the requirements for cache coherency and allowing a simpler implementation and better scalability. Simulation results show that, when additional mechanisms intended to hide remote memory latency are used, execution time of applications that use our proposal is similar to the time required to execute them in a computer populated with enough local memory, thus validating the feasibility of our proposal. We are currently building a prototype that implements our ideas. The first results from real executions in this prototype demonstrate not only that our proposal works but also that it can efficiently execute applications that make use of remote memory resources. © 2011 Springer Science+Business Media, LLC.This work has been supported by PROMETEO from Generalitat Valenciana (GVA) under Grant PROMETEO/2008/060.Montaner Mas, H.; Silla Jiménez, F.; Fröning, H.; Duato Marín, JF. (2012). A new degree of freedom for memory allocation in clusters. Cluster Computing. 15(2):101-123. https://doi.org/10.1007/s10586-010-0150-7S1011231523leaf Systems: http://www.3leafsystems.comAcharya, A., Setia, S.: Availability and utility of idle memory in workstation clusters. ACM SIGMETRICS Perform. Eval. Rev. 27(1), 35–46 (1999). doi: 10.1145/301464.301478Anderson, T., Culler, D., Patterson, D.: A case for NOW (Networks of Workstations). IEEE MICRO 15(1), 54–64 (1995). doi: 10.1109/40.342018HyperTransport Technology Consortium. HyperTransport I/O Link Specification Revision 3.10 (2008). Available at http://www.hypertransport.orgBienia, C., Kumar, S., et al.: The parsec benchmark suite: Characterization and architectural implications. In: Proceedings of the 17th PACT (2008)Chapman, M., Heiser, G.: vNUMA: A virtual shared-memory multiprocessor. In: Proceedings of the 2009 USENIX Annual Technical Conference, San Diego, USA, 2000, pp. 349–362. (2009)Charles, P., Grothoff, C., Saraswat, V., et al.: X10: an object-oriented approach to non-uniform cluster computing. ACM SIGPLAN Not. 40(10), 519–538 (2005)Consortium, H.: HyperTransport High Node Count, Slides. http://www.hypertransport.org/default.cfm?page=HighNodeCountSpecificationConway, P., Hughes, B.: The AMD opteron northbridge architecture. IEEE MICRO 27(2), 10–21 (2007). doi: 10.1109/MM.2007.43Conway, P., Kalyanasundharam, N., Donley, G., et al.: Blade computing with the AMD Opteron processor (Magny-Cours). Hot chips 21 (2009)Duato, J., Silla, F., Yalamanchili, S., et al.: Extending HyperTransport protocol for improved scalability. First International Workshop on HyperTransport Research and Applications (2009)Feeley, M.J., Morgan, W.E., Pighin, E.P., Karlin, A.R., Levy, H.M., Thekkath, C.A.: Implementing global memory management in a workstation cluster. In: SOSP ’95: Proceedings of the Fifteenth ACM Symposium on Operating Systems Principles, pp. 201–212. 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Dev. 52(1/2), 199–220 (2008)IBM z Series: http://www.ibm.com/systems/zIn-Memory Database Systems (IMDSs) Beyond the Terabyte Size Boudary: http://www.mcobject.com/130/EmbeddedDatabaseWhitePapers.htmKeltcher, C., McGrath, K., Ahmed, A., Conway, P.: The AMD opteron processor for multiprocessor servers. Micro IEEE 23(2), 66–76 (2003). doi: 10.1109/MM.2003.1196116Kottapalli, S., Baxter, J.: Nehalem-EX CPU architecture. Hot chips 21 (2009)Liang, S., Noronha, R., Panda, D.: Swapping to remote memory over infiniband: an approach using a high performance network block device. In: Cluster Computing, 2005. IEEE International, pp. 1–10. (2005) doi: 10.1109/CLUSTR.2005.347050Litz, H., Fröning, H., Nuessle, M., Brüening, U.: A hypertransport network interface controller for ultra-low latency message transfers. HyperTransport Consortium White Paper (2007)Litz, H., Fröning, H., Nuessle, M., Brüening, U.: VELO: A novel communication engine for ultra-low latency message transfers. In: 37th International Conference on Parallel Processing, 2008. ICPP ’08, pp. 238–245 (2008). doi: 10.1109/ICPP.2008.85Magnusson, P., Christensson, M., Eskilson, J., et al.: Simics: a full system simulation platform. Computer 35(2), 50–58 (2002). doi: 10.1109/2.982916Martin, M., Sorin, D., Beckmann, B., et al.: Multifacet’s general execution-driven multiprocessor simulator (GEMS) toolset. ACM SIGARCH Comput. Archit. News 33(4), 92–99 (2005) doi: 10.1145/1105734.1105747MBA3 NC Series Catalog: http://www.fujitsu.com/global/services/computing/storage/hdd/ehdd/mba3073nc-mba3300nc.htmlMcCalpin, J.D.: Memory bandwidth and machine balance in current high performance computers. In: IEEE Computer Society Technical Committee on Computer Architecture (TCCA) Newsletter, pp. 19–25 (1995)NUMAChip: http://www.numachip.com/Oguchi, M., Kitsuregawa, M.: Using available remote memory dynamically for parallel data mining application on ATM-connected PC cluster. In: IPDPS 2000. 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Low Power Reversible Parallel Binary Adder/Subtractor

In recent years, Reversible Logic is becoming more and more prominent technology having its applications in Low Power CMOS, Quantum Computing, Nanotechnology, and Optical Computing. Reversibility plays an important role when energy efficient computations are considered. In this paper, Reversible eight-bit Parallel Binary Adder/Subtractor with Design I, Design II and Design III are proposed. In all the three design approaches, the full Adder and Subtractors are realized in a single unit as compared to only full Subtractor in the existing design. The performance analysis is verified using number reversible gates, Garbage input/outputs and Quantum Cost. It is observed that Reversible eight-bit Parallel Binary Adder/Subtractor with Design III is efficient compared to Design I, Design II and existing design.Comment: 12 pages,VLSICS Journa

Numerical simulation of subwoofer arraycon gurations using the Finite ElementMethod

[EN] Teaching in the Master of Acoustic Engineering includes contents that require the modeling of acousticsystems of two types: simple systems through analytical theory and complex models using simulationtechniques. In the present work, we describe an example of complex acoustic sources modeling using the nite element method: subwoofer sound radiation in di erent con gurations. Numerical simulations inthe frequency domain can calculate the radiation pattern of systems that do not have a simple analyticalsolution[ES] La enseñanza en el Máster de Ingeniería Acústica incluye contenido que requiere la modelización de sistemas acústicos de dos tipos: sistemas simples usando la teoría analítica y modelos complejos usando técnicas de simulación. En este trabajo, se describe un ejemplo de modelado de fuentes acústicas complejas mediante el método de los elementos finitos: la radiación sonora del altavoz de subgraves en diferentes configuraciones. Las simulaciones numéricas en el dominio de la frecuencia permiten calcular el patrón de radiación de sistemas que no tienen una solución analítica sencilla.Banyuls-Juan, X.; Atiénzar-Navarro, R.; Picó, R. (2017). Simulación numérica de un conjunto de altavoces subwofers utilizando Elementos Finitos. Modelling in Science Education and Learning. 10(2):203-210. doi:10.4995/msel.2017.7653SWORD203210102Olson, H. (1957). Acoustical Engineering, Second Edition. D. Van Nostrand Company, Princeton, New Jersey.Courant, R., Friedrichs, K., & Lewy, H. (1967). On the Partial Difference Equations of Mathematical Physics. IBM Journal of Research and Development, 11(2), 215-234. doi:10.1147/rd.112.0215La Roda J. (2009). Ajuste de conguraciones cardioides de subgraves. DAS Audio, Departamento de Ingeniería