Self-adaptivity of applications on network on chip multiprocessors: the case of fault-tolerant Kahn process networks

Technology scaling accompanied with higher operating frequencies and the ability to integrate more functionality in the same chip has been the driving force behind delivering higher performance computing systems at lower costs. Embedded computing systems, which have been riding the same wave of success, have evolved into complex architectures encompassing a high number of cores interconnected by an on-chip network (usually identified as Multiprocessor System-on-Chip). However these trends are hindered by issues that arise as technology scaling continues towards deep submicron scales. Firstly, growing complexity of these systems and the variability introduced by process technologies make it ever harder to perform a thorough optimization of the system at design time. Secondly, designers are faced with a reliability wall that emerges as age-related degradation reduces the lifetime of transistors, and as the probability of defects escaping post-manufacturing testing is increased. In this thesis, we take on these challenges within the context of streaming applications running in network-on-chip based parallel (not necessarily homogeneous) systems-on-chip that adopt the no-remote memory access model. In particular, this thesis tackles two main problems: (1) fault-aware online task remapping, (2) application-level self-adaptation for quality management. For the former, by viewing fault tolerance as a self-adaptation aspect, we adopt a cross-layer approach that aims at graceful performance degradation by addressing permanent faults in processing elements mostly at system-level, in particular by exploiting redundancy available in multi-core platforms. We propose an optimal solution based on an integer linear programming formulation (suitable for design time adoption) as well as heuristic-based solutions to be used at run-time. We assess the impact of our approach on the lifetime reliability. We propose two recovery schemes based on a checkpoint-and-rollback and a rollforward technique. For the latter, we propose two variants of a monitor-controller- adapter loop that adapts application-level parameters to meet performance goals. We demonstrate not only that fault tolerance and self-adaptivity can be achieved in embedded platforms, but also that it can be done without incurring large overheads. In addressing these problems, we present techniques which have been realized (depending on their characteristics) in the form of a design tool, a run-time library or a hardware core to be added to the basic architecture

Towards self-adaptive KPN applications on NoC-based MPSoCs

Self-adaptivity is the ability of a system to adapt itself dynamically to internal and external changes. Such a capability helps systems to meet the performance and quality goals, while judiciously using available resources. In this paper, we propose a framework to implement application level self-adaptation capabilities in KPN applications running on NoC-based MPSoCs. The monitor-controller-adapter mechanism is used at the application level. The monitor measures various parameters to check whether the system meets the assigned goals. The controller takes decisions to steer the system towards the goal, which are applied by the adapters. The proposed framework requires minimal modifications to the application code and offers ease of integration. It incorporates a generic adaptation controller based on fuzzy logic. We present the MJPEG encoder as a case study to demonstrate the effectiveness of the approach. Our results show that even if the parameters of the fuzzy controller are not tuned optimally, the adaptation convergence is achieved within reasonable time and error limits. Moreover, the incurred steady-state overhead due to the framework is 4% for average frame-rate, 3.5% for average bit-rate, and 0.5% for additional control data introduced in the network

Ak topraklarda bir kırım yerleşimi: Aksaray/Hamidiye geçiş dönemleri üzerine bir inceleme

The Crimean Tatars, who were subjected to many pressures on the subjects such as forced returning to Christianity and assimilation efforts after the occupation of Crimea by Russia in 1783, had to migrate from their homeland and took refuge in the Ottoman Empire, which they saw as Ak Topraklar. In addition to migrations to Eskisehir, Ankara and Konya, some of the convoys that migrated were located in the area called Hamidiye, 12 km from Aksaray, which is the center of the research. Although the geographical structure of the region has an unproductive soil structure as agriculture, it is suitable for dealing with animal husbandry, and has enabled the people settled in the region to continue their lives. In the research, especially the transition periods of the Crimean Tatars, who continued their cultural existence in this area, where they were settled after migration, were examined in the context of folklore, the mythological elements found in the practices carried out in these periods were determined and tried to be explained and the cultural affinity with the Tatars who continued to live in Crimea.1783’te Kırım’ın Rusya tarafından işgal edilişinin akabinde zoraki Hristiyanlığa döndürme ve asimilasyon çabaları gibi konularda birçok baskıya maruz kalan Kırım Tatarları, yurtlarından göç etmek zorunda kalmış, kafileler halinde Ak Topraklar olarak gördükleri Osmanlı Devleti’ne sığınmışlardır. Ağırlıklı olarak Eskişehir, Ankara, Konya’ya göçler yaşanmasının yanı sıra göç eden kafilelerden bir kısmı araştırmanın merkezini teşkil eden, Aksaray’a 12 km mesafede bulunup Hamidiye olarak adlandırılan sahaya yerleştirilmişlerdir. Bölgenin coğrafi yapısı tarım olarak verimsiz bir toprak yapısına sahip olsa da hayvancılıkla uğraşmak için elverişli olması bölgeye yerleştirilen insanların hayatlarını sürdürmesine imkân sağlamıştır. Araştırmada göçten sonra yerleştirildikleri Türk ve Müslüman olan bu sahada kültürel varlıklarını devam ettiren Kırım Tatarlarının özellikle geçiş dönemleri folklor bağlamında incelenmiş, bu dönemlerde gerçekleştirilen uygulamalarda bulunan mitolojik unsurlar belirlenerek açıklanmaya ve Kırım’da yaşamaya devam eden Tatarlarla olan kültürel yakınlık saptanmaya çalışılmıştır

Surgical advantages of using 3D patient-specific models in high-energy tibial plateau fractures

Aktuglu, Kemal/0000-0001-8058-0364; GOKMEN, Figen/0000-0001-9635-6308WOS: 000530776400003PubMed: 32377923Purpose Treatment of tibial plateau fractures are difficult due to the intra-articular nature of the proximal tibia and extensive involvement of the soft tissue envelope. in this study, we investigated the surgical experience acquired using digitally designed life-size fracture models to guide as a template to place plates and screws in the treatment of tibial plateau fractures and anatomic reduction of joint. Methods 20 tibial plateau frature patients were divided into two equal surgery groups as conventional versus 3D model assisted. the fracture line angles, depression depth, and preoperative/postoperative Rasmussen knee score were measured for each patient. Results the duration of the operation, blood loss volume, turniquet time and number of intraoperative fluoroscopy was 89.5 +/- 5.9 min, 160.5 +/- 15.3 ml, 74.5 +/- 6 min and 10.7 +/- 1.76 times, for 3D printing group and 127 +/- 14.5 min, 276 +/- 44.8 ml, 104.5 +/- 5.5 min and 18.5 +/- 2.17 times for the conventional group, respectively. 3D model-assisted group indicated significantly shorter operation time, less blood loss volume, shorter turniquet and fluoroscopy times, and better outcome than the conventional one. Conclusions the customized 3D model was user friendly, and it provided a radiation-free tibial screw insertion. the use of these models assisted surgical planning, maximized the possibility of ideal anatomical reduction and provided individualized information concerning tibial plateau fractures