A New Parallel Programing Language Fortress:features And Applications

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Bilişim Ensititüsü, 2009Thesis (M.Sc.) -- İstanbul Technical University, Institute of Informatics, 2009Bilgisayar sistemleri çok hızlı bir şekilde büyümektedirler. DARPA, 2010 yılı için peta-ölçekli bir bilgisayar sisteminin gereksinimi ve yapılabilirliğini öngördü. 2003 yılında bir çok firmayla bir proje başlattı. Şimdi, proje bitmek üzereyken ve milyonlarca dolar projeye aktarılmışken, projenin getirisi üç tane yüksek başarımlı yüksek işlevselli programlama dili oldu. Bu dillerden bir tanesi Fortress. Fortress, matematik gösterim temelli, değişken tipleri sıkı olarak takip edilen, blok tabanlı ve kesin olarak paralel bir bilgisayar programlama dilidir. Fortress'i ilginç kılan, yüksek işlevsellikli ve bilim yönlü yapısıdır. Bu çalışmada Fortress'in iç dinamiklerini inceledi. Performansını ölçmek için çeşitli testler yapıldı ve sonuçları tartışıldı.Bilgisayar sistemleri çok hızlı bir şekilde büyümektedirler. DARPA, 2010 yılı için peta-ölçekli bir bilgisayar sisteminin gereksinimi ve yapılabilirliğini öngördü. 2003 yılında bir çok firmayla bir proje başlattı. Şimdi, proje bitmek üzereyken ve milyonlarca dolar projeye aktarılmışken, projenin getirisi üç tane yüksek başarımlı yüksek işlevselli programlama dili oldu. Bu dillerden bir tanesi Fortress. Fortress, matematik gösterim temelli, değişken tipleri sıkı olarak takip edilen, blok tabanlı ve kesin olarak paralel bir bilgisayar programlama dilidir. Fortress'i ilginç kılan, yüksek işlevsellikli ve bilim yönlü yapısıdır. Bu çalışmada Fortress'in iç dinamiklerini inceledi. Performansını ölçmek için çeşitli testler yapıldı ve sonuçları tartışıldı.Yüksek LisansM.Sc

Experimentally determined wear behavior of an Al2O3-SiC composite from 25 to 1200 C

The sliding wear behavior of a self-mated alumina-silicon carbide whisker toughened composite was studied using optical, scanning electron (SEM) and transmission electron (TEM) microscopy. Because of its excellent strength and toughness properties this composite material is under consideration for use in heat engine applications for sliding contacts which operate at elevated temperatures. The composite's wear behavior and especially its wear mechanisms are not well understood. Pin-on-disk specimens were slid in air at 2.7 m/s sliding velocity, under a 26.5-N load, at temperatures 25 to 1200 C. Pin wear increased with increasing temperature. Based upon the microscopic analyses, the wear mechanism seems to be loosening of the reinforcing whiskers due to frictional and bulk heating. This leads to whisker pullout and increased wear

Group Communication Patterns for High Performance Computing in Scala

We developed a Functional object-oriented Parallel framework (FooPar) for high-level high-performance computing in Scala. Central to this framework are Distributed Memory Parallel Data structures (DPDs), i.e., collections of data distributed in a shared nothing system together with parallel operations on these data. In this paper, we first present FooPar's architecture and the idea of DPDs and group communications. Then, we show how DPDs can be implemented elegantly and efficiently in Scala based on the Traversable/Builder pattern, unifying Functional and Object-Oriented Programming. We prove the correctness and safety of one communication algorithm and show how specification testing (via ScalaCheck) can be used to bridge the gap between proof and implementation. Furthermore, we show that the group communication operations of FooPar outperform those of the MPJ Express open source MPI-bindings for Java, both asymptotically and empirically. FooPar has already been shown to be capable of achieving close-to-optimal performance for dense matrix-matrix multiplication via JNI. In this article, we present results on a parallel implementation of the Floyd-Warshall algorithm in FooPar, achieving more than 94 % efficiency compared to the serial version on a cluster using 100 cores for matrices of dimension 38000 x 38000

Thermal influence of welding process on strength overmatching of thin dissimilar sheets joints

The investigation addresses the overall performance of black and white joints (BWJ) of low carbon steel and stainless steel thin sheets achieved by laser hybrid welding. First, thermal field modelling is carried out by considering Goldak’s double ellipsoidal heat source model, together with a contribution of the authors related to the shape coefficients. In parallel, the technological development of BWJ laser hybrid welding is also addressed. Material characterisation by means of macro and microstructural examination and hardness tests is performed. The overall tensile performance of BWJ is discussed together with the weld metal strength overmatching. The tensile tests results indicate that in case of transversally loaded joints, the positive difference in yield between the weld metal and the base materials protects the weld metal from being plastically deformed; the flat transverse tensile specimens loading up to failure reveals large strains in low carbon steel, far away from the wel

Geotechnical remediation of transportation infrastructures: nondestructive evaluation of bridge substructures and stabilization of soft foundation soils

According to the National Research Council (2006), the field of infrastructure development and rehabilitation is one of seven critical categories that require attention of geotechnical researchers and practitioners. Therefore, in this dissertation, two topics related to infrastructure development were selected and studies. These topics were performance of granular shoulders and nondestructive evaluation of low volume road bridge substructures. The first topic investigated common problems associated with granular shoulders, evaluation of several test sections stabilized with selected chemical and mechanical stabilization techniques, laboratory box model, where mechanically stabilized shoulders were tested under cyclic loading, and simple design charts that can help design stable shoulder sections. The second topic evaluates the effectiveness of using nondestructive ultrasonic stress wave tests to determine the internal timber piles conditions and correlate it to capacity of in-service piles. Also, the results of a destructive static load are presented. During this test, the timber piles at one abutment, instrumented with strain gages and load cells, were consecutively damaged to simulate different scenarios of pile deterioration. The influence of this deterioration on the bridge substructure behavior was evaluated

Relating Methanogen Community Structure and Function in Anaerobic Digesters

A deeper understanding of how microbial community structure relates to process function would help improve anaerobic digester design. This dissertation describes both qualitative and quantitative relationships between anaerobic digester function and microbial community structure. Community structure was characterized using banding pattern intensities from denaturing gradient gel electrophoresis (DGGE) for the mcrA gene of methanogenic Archaea. The first project compared a single-stage continuously mixed stirred tank reactor (CSTR) and staging with an acidogenic CSTR followed by a methanogenic CSTR. After seeding with the same biomass, these unique process configurations exhibited different function and qualitatively different methanogen communities. Compared to a single-stage CSTR, staging increased the maximum rate of methane production by 41, 26, and 57% with propionate, acetate, and hydrogen, respectively. Additionally, the staged digester produced 10% more methane and achieved 10% greater volatile solids (VS) destruction. The second project also provided a qualitative relationship: methanogen community structure impacted digester function upon bioaugmentation. Specific methanogenic activity (SMA) with propionate statistically increased (up to 57%) in six of nine bioaugmented anaerobic cultures. These increases correlated to methanogen community structure above the 98% level (rs = 0.770) using Spearman’s Rank Correlation Coefficient (two-tailed). In the third project, a quantitative structure-activity relationship (QSAR) was established between methanogen community structure and two activities using multiple linear regression (MLR). Two different QSARs were predictive of SMA values with propionate (q2 = 0.52) and with glucose (q2 = 0.56), respectively. A MLR model may be applicable to other biological communities when trophic redundancy and a ubiquitous gene are present and when a linear model is appropriate. Greater understanding of anaerobic digester microbial communities is possible using these QSARs. This research serves as a template that can be used to construct additional QSARs for other complex microbial communities in engineered systems

Experimental and Analytical Study of Masonry Infill Reinforced Concrete Frames Retrofitted with Steel Braces

In the present work a seismic retrofitting technique is proposed for masonry infilled reinforced concrete frames based on the replacement of infill panels by K-bracing with vertical shear link. The performance of this technique is evaluated through experimental tests. A simplified numerical model for structural damage evaluation is also formulated according to the notions and principles of continuum damage mechanics. The proposed model is calibrated with the experimental results. The experimental results have shown an excellent energy dissipation capacity with the proposed technique. Likewise, the numerical predictions with the proposed model are in good agreement with experimental results

Tribological characteristics of silicon carbide whisker-reinforced alumina at elevated temperatures

The enhanced fracture toughness of whisker reinforced ceramics makes them attractive candidates for sliding components of advanced hear engines. Examples include piston rings and valve stems for Stirling engines and other low heat rejection devices. However, the tribological behavior of whisker reinforced ceramics is largely unknown. This is especially true for the applications described where use temperatures can vary from below ambient to well over 1000 C. An experimental research program to identify the dominant wear mechanism(s) for a silicon carbide whisker reinforced alumina composite, SiCw-Al2O3 is described. In addition, a wear mechanism model is developed to explain and corroborate the experimental results and to provide insight for material improvement