Counting points on elliptic curves over Zp

The mathematics of elliptic curves has been studied since ancient times. These mathematical structures have found applications in varied fields. More recently, there has been a growing interest in applying these structures to cryptography. Various such applications have been proposed. Elliptic curve based cryptographic algorithms have been shown to provide greater security with shorter key sizes than the conventional RSA based cryptosystems, making them more memory e cient and less processor intensive. One of the fundamental requirements of all such elliptic curve cryptographic algorithms is that the order of the group of points satisfying the elliptic curve meet a certain set of requirements. However, finding the group order is not a trivial task. There are numerous special cases of elliptic curves where determining the group order is trivial. This thesis however, deals with the study of general point counting algorithms and their performances, which are applicable to all the curves. Possible improvements to the algorithms are provided where possible

Automatic Energy Saving Schemes for Parallel Applications

Although high-performance computing traditionally focuses on the efficient execution of large-scale applications, both energy and power have become critical concerns when approaching exascale. Drastic increases in the power consumption of supercomputers affect significantly their operating costs and failure rates. In modern microprocessor architectures, equipped with dynamic voltage and frequency scaling (DVFS) and CPU clock modulation (throttling), the power consumption may be controlled in software. Additionally, network interconnect, such as Infiniband, may be exploited to maximize energy savings while the application performance loss and frequency switching overheads must be carefully balanced. This work first studies two important collective communication operations, all-to-all and allgather and proposes energy saving strategies on the per-call basis. Next, it targets point-to-point communications to group them into phases and apply frequency scaling to them to save energy by exploiting the architectural and communication stalls. Finally, it proposes an automatic runtime system which combines both collective and point-to-point communications into phases, and applies throttling to them apart from DVFS to maximize energy savings. The experimental results are presented for NAS parallel benchmark problems as well as for the realistic parallel electronic structure calculations performed by the widely used quantum chemistry package GAMESS. Close to the maximum energy savings were obtained with a substantially low performance loss on the given platform

Distributed Strategy for Power Re-Allocation in High Performance Applications

To improve the power consumption of parallel applications at the runtime, modern processors provide frequency scaling and power limiting capabilities. In this work, a runtime strategy is proposed to distribute a given power allocation among the cluster nodes assigned to the application while balancing their performance change. The strategy operates in a timeslice-based manner to estimate the current application performance and power usage per node followed by power redistribution across the nodes. Experiments, performed on four nodes (112 cores) of a modern computing platform interconnected with Infiniband showed that even a significant power budget reduction of 20% may result in a performance degradation of as low as 1% under the proposed strategy compared with the execution in the unlimited power cas

Runtime Energy Savings Based on Machine Learning Models for Multicore Applications

To improve the power consumption of parallel applications at the runtime, modern processors provide frequency scaling and power limiting capabilities. In this work, a runtime strategy is proposed to maximize energy savings under a given performance degradation. Machine learning techniques were utilized to develop performance models which would provide accurate performance prediction with change in operating core-uncore frequency. Experiments, performed on a node (28 cores) of a modern computing platform showed significant energy savings of as much as 26% with performance degradation of as low as 5% under the proposed strategy compared with the execution in the unlimited power case

Perspectives of Tribal Communities on NTFP Resource Use in a Global Hotspot: Implications for Adaptive Management

Tribal communities depend on a large variety of Non-timber forest products (NTFPs) for their diverse needs, which has attracted high interest in recent years in view of increasing rural incomes and stimulating the forest management. This study investigates forest dependent (NTFPs based) livelihood in an ethnically diverse area in Northeast India, a global hotspot. We addressed two research questions: (1) what is the diversity of NTFPs resources that communities extract from the forest reserves to supplement their home needs? and (2) what are the perceptions of communities about sustainable development of NTFPs resources? We recorded 343 plant species that were used to fulfill varied needs of five tribal communities. Of them, 32% species harvested for their leaves and 27% for fruits. Dependence on NTFPs was more at high mountains. The seasonal use of NTFPs revealed that 79% species collected during lean period. Community perception on use of NTFPs revealed that 11% species consumed most frequently and 53% commonly. It was interesting to note that community residents sell as many as 76 species in the local markets to earn cash. All households collect NTFPs for sustenance while 31-41% households involved in commercial collection of species, viz. Taxus wallichiana, Aconitum fletcherianum, Ophiocordyceps sinensis, Swertia chirayita, Illicium griffithii, and Thalictrum foliolosum. There was a gradual decrease in use of NTFPs with young age because of high labour and availability of other options. The communities perceived that unscientific and excessive harvesting may threatened these species in near future. For adaptive management of NTFPs, communities suggested that capacity building on maximum allowable harvests and yield regulation measures, tenure improvement, domestication and plantations of selected species along with access to markets for NTFPs products will create better economic gains for communities at the same time it will lead to sustainable management of NTFPs.   Keywords: Northeast India; global hotspot; NTFPs; sustainable use; consumption pattern; enterprises; livelihoods; adaptive managemen

Perspectives of Tribal Communities on NTFP Resource Use in a Global Hotspot: Implications for Adaptive Management

Tribal communities depend on a large variety of Non-timber forest products (NTFPs) for their diverse needs, which has attracted high interest in recent years in view of increasing rural incomes and stimulating the forest management. This study investigates forest dependent (NTFPs based) livelihood in an ethnically diverse area in Northeast India, a global hotspot. We addressed two research questions: (1) what is the diversity of NTFPs resources that communities extract from the forest reserves to supplement their home needs? and (2) what are the perceptions of communities about sustainable development of NTFPs resources? We recorded 343 plant species that were used to fulfill varied needs of five tribal communities. Of them, 32% species harvested for their leaves and 27% for fruits. Dependence on NTFPs was more at high mountains. The seasonal use of NTFPs revealed that 79% species collected during lean period. Community perception on use of NTFPs revealed that 11% species consumed most frequently and 53% commonly. It was interesting to note that community residents sell as many as 76 species in the local markets to earn cash. All households collect NTFPs for sustenance while 31-41% households involved in commercial collection of species, viz. Taxus wallichiana, Aconitum fletcherianum, Ophiocordyceps sinensis, Swertia chirayita, Illicium griffithii, and Thalictrum foliolosum. There was a gradual decrease in use of NTFPs with young age because of high labour and availability of other options. The communities perceived that unscientific and excessive harvesting may threatened these species in near future. For adaptive management of NTFPs, communities suggested that capacity building on maximum allowable harvests and yield regulation measures, tenure improvement, domestication and plantations of selected species along with access to markets for NTFPs products will create better economic gains for communities at the same time it will lead to sustainable management of NTFPs.   Keywords: Northeast India; global hotspot; NTFPs; sustainable use; consumption pattern; enterprises; livelihoods; adaptive managemen