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Computing devices of all types have almost converged to using central processing units featuring multiple processing cores. In order to develop efficient software for such devices, programmers need to learn how to write parallel programs. We present an infrastructure to support parallel programming assignments for online courses. We developed an extension to the Open edX platform with a backend that handles the execution of student codes on a cluster lab. The web user interface offers instructors a wide range of configuration options for the programming assignments as well as a flexible definition of criteria for automatic grading. We have successfully integrated the software with Open edX and tested it with a real parallel programming cluster lab.

Lymphangiomatosis is a rare congenital disease; diagnosis is made in the first 2 decades and affects almost all body parts. Imaging findings play an important role in the diagnosis. We present a case of a patient with lymphangiomatosis whose diagnosis was made solely with imaging findings; we also include a small review of the topic. Keywords: Chylothorax, Lymphangioma

El seno del segundo arco branquial es una alteracion secundaria a un desarrollo anormal de los arcos branquiales. Las anomalias de los arcos branquiales incluyen quistes, fistulas, senos y glandulas ectopicas. Deben ser consideradas en el diagnostico diferencial de las masas en cuello de pacientes adultos o pediatricos. El seno del arco branquial supone alrededor del 30 % de las masas congenitas del cuello y suele ser diagnosticado en la segunda a tercera decada de la vida, siendo mas comunes las del segundo arco. Se presenta con sintomas inespecificos. Los estudios de imagenes son esenciales para su diagnostico, clasificacion y manejo quirurgico. Se presenta el caso de un paciente de 67 anos con historia clinica y examen fisico de seno del segundo arco branquial, quien requirio de fistulografia y tomografia computarizada para una adecuada caracterizacion. El paciente fue intervenido quirurgicamente sin complicaciones posteriormente. DOI: http://dx.doi.org/10.21615/cesmedicina.32.2.9

We present an experimental performance comparison of lossless compression programs for DNA raw data in FASTQ format files. General-purpose (PBZIP2, P7ZIP and PIGZ) and domain-specific compressors (SCALCE, QUIP, FASTQZ and DSRC) were analyzed in terms of compression ratio, execution speed, parallel scalability and memory consumption. Results showed that domain-specific tools increased the compression ratios up to 70 %, while reducing the runtime of general-purpose tools up to $$7\times $$ during compression and up to $$3\times $$ during decompression. Parallelism scaled performance up to $$13\times $$ when using 20 threads. Our analysis indicates that QUIP, DSRC and PBZIP2 are the best tools in their respective categories, with acceptable memory requirements. Nevertheless, the end user must consider the features of available hardware and define the priorities among its optimization objectives (compression ratio, runtime during compression or decompression, scalability, etc.) to properly select the best application for each particular scenario.

The Inferior-Olivary nucleus (ION) is a well-charted region of the brain, heavily associated with sensorimotor control of the body. It comprises ION cells with unique properties which facilitate sensory processing and motor-learning skills. Various simulation models of ION-cell networks have been written in an attempt to unravel their mysteries. However, simulations become rapidly intractable when biophysically plausible models and meaningful network sizes (100 cells) are modeled. To overcome this problem, in this work we port a highly detailed ION cell network model, originally coded in Matlab, onto an FPGA chip. It was first converted to ANSI C code and extensively profiled. It was, then, translated to HLS C code for the Xilinx Vivado toolflow and various algorithmic and arithmetic optimizations were applied. The design was implemented in a Virtex 7 (XC7VX485T) device and can simulate a 96-cell network at real-time speed, yielding a speedup of 700 compared to the original Matlab code and 12.5 compared to the reference C implementation running on a Intel Xeon 2.66GHz machine with 20GB RAM. For a 1,056-cell network (non-real-time), an FPGA speedup of 45 against the C code can be achieved, demonstrating the design's usefulness in accelerating neuroscience research. Limited by the available on-chip memory, the FPGA can maximally support a 14,400-cell network (non-real-time) with online parameter configurability for cell state and network size. The maximum throughput of the FPGA IONnetwork accelerator can reach 2.13 GFLOPS.

The DeSyRe project builds on-demand adaptive, reliable Systems-on-Chips. In response to the current semiconductor technology trends thatmake chips becoming less reliable, DeSyRe describes a newgeneration of by design reliable systems, at a reduced power and performance cost. This is achieved through the following main contributions. DeSyRe defines a fault-tolerant system architecture built out of unreliable components, rather than aiming at totally fault-free and hence more costly chips. In addition, DeSyRe systems are on-demand adaptive to various types and densities of faults, as well as to other system constraints and application requirements. For leveraging on-demand adaptation/customization and reliability at reduced cost, a new dynamically reconfigurable substrate is designed and combined with runtime system software support. The above define a generic and repeatable design framework, which is applied to two medical SoCs with high reliability constraints and diverse performance and power requirements. One of the main goals of the DeSyRe project is to increase the availability of SoC components in the presence of permanents faults, caused at manufacturing time or due to device aging. A mix of coarse- and fine-grain reconfigurable hardware substrate is designed to isolate and bypass faulty component parts. The flexibility provided by the DeSyRe reconfigurable substrate is exploited at runtime by system optimization heuristics,which decide tomodify component configurationwhen a permanent fault is detected, providing graceful degradation.

Exponential growth in biological sequence data combined with the computationally intensive nature of bioinformatics applications results in a continuously rising demand for processing power. In this paper, we propose a performance model that captures the behavior and performance scalability of HMMER, a bioinformatics application that identifies similarities between protein sequences and a protein family model. With our analytical model, the optimal master-worker ratio for a user scenario can be estimated. The model is evaluated and is found accurate with less than 2% error. We applied our model to a widely used heterogeneous multicore, the Cell BE, using the PPE and SPEs as master and workers respectively. Experimental results show that for the current parallelization strategy, the I/O speed at which the database is read from disk and the inputs pre-processing are the two most limiting factors in the Cell BE case.

In bioinformatics, protein sequence alignment is one of the fundamental tasks that scientists perform. Since the growth of biological data is exponential, there is an ever-increasing demand for computational power. While current processor technology is shifting towards the use of multicores, the mapping and parallelization of applications has become a critical issue. In order to keep up with the processing demands, applications' bottlenecks to performance need to be found and properly addressed. In this paper we study the parallelism and performance scalability of HMMER, a bioinformatics application to perform sequence alignment. After our study of the bottlenecks in a HMMER version ported to the Cell processor, we present two optimized versions to improve scalability in a larger multicore architecture. We use a simulator that allows us to model a system with up to 512 processors and study the performance of the three parallel versions of HMMER. Results show that removing the I/O bottleneck improves performance by 3X and 2.4X for a short and a long HMM query respectively. Additionally, by offloading the sequence pre-formatting to the worker cores, larger speedups of up to 27X and 7X are achieved. Compared to using a single worker processor, up to 156X speedup is obtained when using 256 cores.

Sequence alignment is one of the fundamental tasks in bioinformatics. Due to the exponential growth of biological data and the computational complexity of the algorithms used, high performance computing systems are required. Although multicore architectures have the potential of exploiting the task-level parallelism found in these workloads, efficiently harnessing systems with hundreds of cores requires deep understanding of the applications and the architecture. When incorporating large numbers of cores, performance scalability will likely saturate shared hardware resources like buses and memories. In this paper we evaluate the performance impact of various configurations of an accelerator-based multicore architecture with the aim of revealing and quantifying the bottlenecks. Then, we compare against a multicore using general-purpose processors and discuss the performance gap. Our target application is ClustalW, one of the most popular programs for Multiple Sequence Alignment. Different input data sets are characterized and we show how they influence performance. Simulation results show that due to the high computation-to-communication ratio and the transfer of data in large chunks, memory latency is well tolerated. However, bandwidth is critical to achieving maximum performance. Using a 32KB cache configuration with 4 banks can capture most of the memory traffic and therefore avoid expensive off-chip transactions. On the other hand, using a hardware queue for the tasks synchronization allows us to handle a large number of cores. Finally, we show that using a simple load balancing strategy, we can increase performance of general-purpose cores by 28%.

This paper includes a strategic analysis of Hotel Industry in Colombia, and an analysis of the turbulence business environment.

Sequence alignment is a fundamental instrument in Bioinformatics. In recent years, numerous proposals have been addressing the problem of accelerating this class of applications. This, due to the rapid growth of sequence databases in combination with the high computational demands imposed by the algorithms. In this paper we focus on the analysis of the progressive alignment in ClustalW, a widely used program for performing multiple sequence alignment. We have parallelized ClustalW for the Cell processor architecture and have carefully analyzed the scalability of its different phases with both the number of cores used and the input size. Experimental results show that computing profile scores scales well up to 16 SPE cores. With the increase of the input size, profiles initialization in the PPE core becomes the predominant bottleneck.

The fast growth of bioinformatics field has attracted the attention of computer scientists in the last few years. At the same time the increasing database sizes require greater efforts to improve the computational performance. From a computer architecture point of view, we intend to investigate how bioinformatics applications can benefit from future multi-core processors. In this paper we present a preliminary study of the Cell BE processor limitations when executing two representative sequence alignment applications (Ssearch and ClustalW). The inherent large parallelism of the targeted algorithms makes them ideal for architectures supporting multiple dimensions of parallelism (TLP and DLP). However, in the case of Cell BE we identified several architectural limitations that need a careful study and quantification.

The SARC architecture is composed of multiple processor types and a set of user-managed direct memory access (DMA) engines that let the runtime scheduler overlap data transfer and computation. The runtime system automatically allocates tasks on the heterogeneous cores and schedules the data transfers through the DMA engines. SARC's programming model supports various highly parallel applications, with matching support from specialized accelerator processors.