Invasive compute balancing for applications with shared and hybrid parallelization

This is the author manuscript. The final version is available from the publisher via the DOI in this record.Achieving high scalability with dynamically adaptive algorithms in high-performance computing (HPC) is a non-trivial task. The invasive paradigm using compute migration represents an efficient alternative to classical data migration approaches for such algorithms in HPC. We present a core-distribution scheduler which realizes the migration of computational power by distributing the cores depending on the requirements specified by one or more parallel program instances. We validate our approach with different benchmark suites for simulations with artificial workload as well as applications based on dynamically adaptive shallow water simulations, and investigate concurrently executed adaptivity parameter studies on realistic Tsunami simulations. The invasive approach results in significantly faster overall execution times and higher hardware utilization than alternative approaches. A dynamic resource management is therefore mandatory for a more efficient execution of scenarios similar to our simulations, e.g. several Tsunami simulations in urgent computing, to overcome strong scalability challenges in the area of HPC. The optimizations obtained by invasive migration of cores can be generalized to similar classes of algorithms with dynamic resource requirements.This work was supported by the German Research Foundation (DFG) as part of the Transregional Collaborative Research Centre ”Invasive Computing” (SFB/TR 89)

Invasive Computing in HPC with X10

High performance computing with thousands of cores relies on distributed memory due to memory consistency reasons. The resource management on such systems usually relies on static assignment of resources at the start of each application. Such a static scheduling is incapable of starting applications with required resources being used by others since a reduction of resources assigned to applications without stopping them is not possible. This lack of dynamic adaptive scheduling leads to idling resources until the remaining amount of requested resources gets available. Additionally, applications with changing resource requirements lead to idling or less efficiently used resources. The invasive computing paradigm suggests dynamic resource scheduling and applications able to dynamically adapt to changing resource requirements. As a case study, we developed an invasive resource manager as well as a multigrid with dynamically changing resource demands. Such a multigrid has changing scalability behavior during its execution and requires data migration upon reallocation due to distributed memory systems. To counteract the additional complexity introduced by the additional interfaces, e. g. for data migration, we use the X10 programming language for improved programmability. Our results show improved application throughput and the dynamic adaptivity. In addition, we show our extension for the distributed arrays of X10 to support data migrationThis work was supported by the German Research Foundation (DFG) as part of the Transregional Collaborative Research Centre “Invasive Computing” (SFB/TR 89)

Catheter Ablation of Atrial Fibrillation in Patients with Previous Lobectomy or Partial Lung Resection: Long-Term Results of an International Multicenter Study

Introduction: Data regarding the efficacy of catheter ablation in patients with atrial fibrillation (AF) and patients' previous history of pulmonary lobectomy/pneumonectomy are scanty. We sought to evaluate the efficacy and long-term follow-up of catheter ablation in this highly selected group of patients. Material and Methods: Twenty consecutive patients (8 females, 40%; median age 65.2 years old) with a history of pneumonectomy/lobectomy and paroxysmal or persistent AF, treated by means of pulmonary vein isolation (PVI) at ten participating centers were included. Procedural success, intra-procedural complications, and AF recurrences were considered. Results: Fifteen patients had a previous lobectomy and five patients had a complete pneumonectomy. A large proportion (65%) of PV stumps were electrically active and represented a source of firing in 20% of cases. PVI was performed by radiofrequency ablation in 13 patients (65%) and by cryoablation in the remaining 7 cases. Over a median follow up of 29.7 months, a total of 7 (33%) AF recurrences were recorded with neither a difference between patients treated with cryoablation or radiofrequency ablation or between the two genders. Conclusions: Catheter ablation by radiofrequency ablation or cryoablation in patients with pulmonary stumps is feasible and safe. Long-term outcomes are favorable, and a similar efficacy of catheter ablation has been noticed in both males and females

Generation of an induced pluripotent stem cell cohort suitable to investigate sporadic Alzheimer's Disease

Alzheimer's Disease (AD) is the major cause of dementia in the elderly, and cortical neurons differentiated from patient-derived induced pluripotent stem cells (iPSCs) can recapitulate disease phenotypes such as tau phosphorylation or amyloid beta (Aß) deposition. Here we describe the generation of an iPSC cohort consisting of 2 sporadic AD cases and 3 controls, derived from dermal fibroblasts. All lines were karyotypically normal, showed expression of stem cell markers and efficiently differentiated into cells of all three germ layers

The USSR and the Second Vienna Arbitration: Diplomatic Assessment of the Results and Consequences (Anatoly Salkov)

Раздел "Международные отношения"As a result of World War I according to the 1920 Trianon Peace Treaty Romania gained about 32% of the territory of the Kingdom of Hungary including multinational Transylvania, whereas the post-war Hungary itself got only about 29%. That is why the core content of the Hungarian foreign policy, marked by expansionism, was the revision of this treaty. By the decision of the Second Vienna Arbitration, held by Germany and Italy on August 30,1940, Romania handed over Northern Transylvania to Hungary and received guarantees for its new borders. The arbitration exacerbated the national and territorial contradictions and strengthened the dependence of both antagonists on Germany. German troops were deployed in Romania. The assessment of the results and consequences of the arbitration by the interested parties, which is based on new documents is of special importance. It was perceived as national tragedy in Romania, but Berlin gave appeasing statements on the Transylvania and Bessarabia concessions being of temporary nature. The Budapest assessment added up to the arbitration decision having been taken in favour of Germany but not of Hungary which, on gaining territory, gained a very inconvenient boundary line. In fact, its situation proved to be less favourable that it had been before. The comprehensive assessment of the Transylvania decision of Germany as not a final one was given by A. Hitler himself. Most important was the USSR reaction which was displayed in two talks between F. Schulenburg and V Molotov on August 31 and September 9. Moscow's resentment was based on the German side's violation of article III of the Soviet-German treaty from August 23, 1939 and focused on 4 issues: 1. It was agreed back in June, that the statements of the German ambassador to Rome G. Makensen in his talk with the Russian charge' d'affaires L. Gelfand on May 20 on Germany and Italy needing to settle the problems of the Balkans and South-East of Europe jointly with the USSR, were his personal opinion, but not the point of view of the German government. 2. The Vienna decision referred to the issues which required consultations and informing, because it was the question of two countries neighbouring the Soviet Union. But Germany merely informed the Soviet Union postfactum. 3. While deciding the fate of Bessarabia and Bukovina the USSR had informed Germany beforehand, waited for its answer to take a decision, took Berlin's position into account and limited its Bukovina claims by its northern part. 4. During the period of taking a decision on Northern Bukovina Molotov expressed hope, that, when the circumstances were favourable, Germany would support Soviet claims to Southern Bukovina as well. But the guarantees for the new Romanian border conflicted with these plans. The acute resentment of the Soviet side was determined by the fact that its territorial claims had not been taken into account at all when they collided with the greater interests of Berlin. Soviet discontent became the object of constant discussions in diplomatic circles in Moscow and was recognized to be the first serious tension between the Soviets and the Axis Powers. The Romanian envoy to Moscow G. Gafenku even classified various diplomatic evaluations of the obvious Soviet discontent and identified two parameters: 1. Moscow was not satisfied by the form of the settlement of the problem. The USSR considered it to be its gained right to participate in the rearrangement in the Danube basin and in the Balkans. 2. Moscow was not happy about the content of the Vienna decisions either. It was connected with unclear delimitation in 1939 of Soviet and German zones of influence in the South-East of Europe, which allowed the USSR to keep hope to "implement sometime the dream of the exclusive supremacy in the Black Sea and the straits". But Germany set up a barrier for these plans in Vienna because the Germans reached the Black Sea via Romanian Constanza, so that the Danube became, in fact, a German river. So Gafenku came finally to the conclusion that the arbitration and its consequences "were the first diplomatic defeat of J. Stalin, who had learned to achieve great victories at small risk. This defeat was the more painful because it affected the dream which had always been most dear for the Russian soul — the dream about the South". The Soviet appeals to the Romanian guarantees, obtained in Vienna, were connected with the most important international events later on too. They were heard during the notorious visit of Molotov to Berlin on November 12—13, 1940, they were used as a factor of pressure on Italy during its attempts to resume economic negotiations with the USSR. In the course of Soviet-German rivalry in the Balkans the Soviet Union made an unsuccessful attempt to establish control over Bulgaria. The latter was urged to accept precisely the Romanian variant: in exchange for the Moscow support of its claim for western Phrakia and access to the Aegean Sea Soviet troops were to be deployed there and new borders were to be guaranteed. Thus, starting with the autumn of 1940 and right up to the beginning of the war between the USSR and Germany, the Transylvania arbitration and the guarantees of the borders established for Romania, as well as Moscow's discontent with these decisions became essential and constant aspects of the Soviet policy in the Balkans and the USSR relations with the Axis countries