489 research outputs found
The role of field redefinition on renormalisability of a general supersymmetric gauge theories
We investigate some issues on renormalisability of non-anticommutative
supersymmetric gauge theory related to field redefinitions. We study one loop
corrections to supersymmetric gauge theory
coupled to chiral matter in component formalism, and show the procedure which
has been introduced for renormalisation is problematic because some terms which
are needed for the renormalisability of theory are missed from the Lagrangian.
In order to prove the theory is renormalisable, we redefine the gaugino and the
auxiliary fields(), which result in a modified form of the
Lagrangian in the component formalism. Then, we show the modified Lagrangian
has extra terms which are necessary for renormalisability of
non-anticommutative supersymmetric gauge field theories. Finally we prove supersymmetric gauge theory is renormalisable up to one loop
corrections using standard method of renormalisation; besides, it is shown the
effective action is gauge invariant.Comment: arXiv admin note: text overlap with arXiv:hep-th/0505248 by other
author
HAPPY: Hybrid Address-based Page Policy in DRAMs
Memory controllers have used static page closure policies to decide whether a
row should be left open, open-page policy, or closed immediately, close-page
policy, after the row has been accessed. The appropriate choice for a
particular access can reduce the average memory latency. However, since
application access patterns change at run time, static page policies cannot
guarantee to deliver optimum execution time. Hybrid page policies have been
investigated as a means of covering these dynamic scenarios and are now
implemented in state-of-the-art processors. Hybrid page policies switch between
open-page and close-page policies while the application is running, by
monitoring the access pattern of row hits/conflicts and predicting future
behavior. Unfortunately, as the size of DRAM memory increases, fine-grain
tracking and analysis of memory access patterns does not remain practical. We
propose a compact memory address-based encoding technique which can improve or
maintain the performance of DRAMs page closure predictors while reducing the
hardware overhead in comparison with state-of-the-art techniques. As a case
study, we integrate our technique, HAPPY, with a state-of-the-art monitor, the
Intel-adaptive open-page policy predictor employed by the Intel Xeon X5650, and
a traditional Hybrid page policy. We evaluate them across 70 memory intensive
workload mixes consisting of single-thread and multi-thread applications. The
experimental results show that using the HAPPY encoding applied to the
Intel-adaptive page closure policy can reduce the hardware overhead by 5X for
the evaluated 64 GB memory (up to 40X for a 512 GB memory) while maintaining
the prediction accuracy
DReAM: Dynamic Re-arrangement of Address Mapping to Improve the Performance of DRAMs
The initial location of data in DRAMs is determined and controlled by the
'address-mapping' and even modern memory controllers use a fixed and
run-time-agnostic address mapping. On the other hand, the memory access pattern
seen at the memory interface level will dynamically change at run-time. This
dynamic nature of memory access pattern and the fixed behavior of address
mapping process in DRAM controllers, implied by using a fixed address mapping
scheme, means that DRAM performance cannot be exploited efficiently. DReAM is a
novel hardware technique that can detect a workload-specific address mapping at
run-time based on the application access pattern which improves the performance
of DRAMs. The experimental results show that DReAM outperforms the best
evaluated address mapping on average by 9%, for mapping-sensitive workloads, by
2% for mapping-insensitive workloads, and up to 28% across all the workloads.
DReAM can be seen as an insurance policy capable of detecting which scenarios
are not well served by the predefined address mapping
Adaptive railway traffic control using approximate dynamic programming
This study presents an adaptive railway traffic controller for real-time operations based on approximate dynamic programming (ADP). By assessing requirements and opportunities, the controller aims to limit consecutive delays resulting from trains that entered a control area behind schedule by sequencing them at critical locations in a timely manner, thus representing the practical requirements of railway operations. This approach depends on an approximation to the value function of dynamic programming after optimisation from a specified state, which is estimated dynamically from operational experience using reinforcement learning techniques. By using this approximation, the ADP avoids extensive explicit evaluation of performance and so reduces the computational burden substantially. In this investigation, we explore formulations of the approximation function and variants of the learning techniques used to estimate it. Evaluation of the ADP methods in a stochastic simulation environment shows considerable improvements in consecutive delays by comparison with the current industry practice of First-Come-First-Served sequencing. We also found that estimates of parameters of the approximate value function are similar across a range of test scenarios with different mean train entry delays
Tunability of terahertz random lasers with temperature based on superconducting materials
We theoretically demonstrate the tunabiltiy of terahertz random lasers composed of high temperature superconductorYBCO and ruby layers as active medium. The considered system is a one-dimensional disordered medium made of ruby grain and YBCO. Finite-difference time domain method is used to calculate the emission spectrum and spatial distribution of electric field at different temperatures. Our numerical results reveal that the superconductor based random lasers exhibit large temperature tunability in the terahertz domain. The emission spectrum is significantly temperature dependent, the number of lasing modes and their intensities increase with decreasing temperature. Also, we make some discussion to explain the reason for the observed tunability and the effect of temperature variation on the spatial distribution of the electric field in the disordered active medium
Evaluation of Environmental Effects in Producing Three Main Crops (Corn, Wheat and Soybean) Using Life Cycle Assessment
Today, environmental pollution and greenhouse gases emissions are one of the human society challenges which is attracted many countries, scientists and researchers attention. To control and reduce the pollution needed to track the environmental impact during the production of the desired product. Since the world's population is growing, the demand for food has increased. Therefore, the agricultural industry required to appropriate policy management to reduce the environmental impacts for producing the healthier products. LCA approach specifies the environmental impact during the production of the interest product. In addition, three crops of corn, wheat and soybean were announced as ten of world's first listwith universal value. Therefore, producing these crops according to the type of planting and the rate of inputs consumption and also identified the negative impacton environment during planting is essential for the proper management of resources. After collecting and classifying information about these three crops, we enter those information in SimaPro software. According to the obtained results, the amount of acidification and photochemical oxidation indicators for wheat, corn and soybean was calculated to be 16.7427, 14.8964, 6.6459 kg eq and 0.7145, 0.6342, 0.359 kg eq, respectively. Therefore, the results showed that the maximum amount of acidities and photochemical oxidation were belonged to the wheat production. Also in another environmental indicators soybean producthad the maximum amounts. Finally, to reduce environment impacts of production, some solution has been provided for resource consumption management
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