Non-Malleable Extractors and Codes, with their Many Tampered Extensions

Randomness extractors and error correcting codes are fundamental objects in computer science. Recently, there have been several natural generalizations of these objects, in the context and study of tamper resilient cryptography. These are seeded non-malleable extractors, introduced in [DW09]; seedless non-malleable extractors, introduced in [CG14b]; and non-malleable codes, introduced in [DPW10]. However, explicit constructions of non-malleable extractors appear to be hard, and the known constructions are far behind their non-tampered counterparts. In this paper we make progress towards solving the above problems. Our contributions are as follows. (1) We construct an explicit seeded non-malleable extractor for min-entropy $k \geq \log^2 n$. This dramatically improves all previous results and gives a simpler 2-round privacy amplification protocol with optimal entropy loss, matching the best known result in [Li15b]. (2) We construct the first explicit non-malleable two-source extractor for min-entropy $k \geq n-n^{\Omega(1)}$, with output size $n^{\Omega(1)}$ and error $2^{-n^{\Omega(1)}}$. (3) We initiate the study of two natural generalizations of seedless non-malleable extractors and non-malleable codes, where the sources or the codeword may be tampered many times. We construct the first explicit non-malleable two-source extractor with tampering degree $t$ up to $n^{\Omega(1)}$, which works for min-entropy $k \geq n-n^{\Omega(1)}$, with output size $n^{\Omega(1)}$ and error $2^{-n^{\Omega(1)}}$. We show that we can efficiently sample uniformly from any pre-image. By the connection in [CG14b], we also obtain the first explicit non-malleable codes with tampering degree $t$ up to $n^{\Omega(1)}$, relative rate $n^{\Omega(1)}/n$, and error $2^{-n^{\Omega(1)}}$.Comment: 50 pages; see paper for full abstrac

Perceptron Learning in Cache Management and Prediction Techniques

Hardware prefetching is an effective technique for hiding cache miss latencies in modern processor designs. An efficient prefetcher should identify complex memory access patterns during program execution. This ability enables the prefetcher to read a block ahead of its demand access, potentially preventing a cache miss. Accurately identifying the right blocks to prefetch is essential to achieving high performance from the prefetcher. Prefetcher performance can be characterized by two main metrics that are generally at odds with one another: coverage, the fraction of baseline cache misses which the prefetcher brings into the cache; and accuracy, the fraction of prefetches which are ultimately used. An overly aggressive prefetcher may improve coverage at the cost of reduced accuracy. Thus, performance may be harmed by this over-aggressiveness because many resources are wasted, including cache capacity and bandwidth. An ideal prefetcher would have both high coverage and accuracy. In this thesis, I propose Perceptron-based Prefetch Filtering (PPF) as a way to increase the coverage of the prefetches generated by a baseline prefetcher without negatively impacting accuracy. PPF enables more aggressive tuning of a given baseline prefetcher, leading to increased coverage by filtering out the growing numbers of inaccurate prefetches such an aggressive tuning implies. I also explore a range of features to use to train PPF’s perceptron layer to identify inaccurate prefetches. PPF improves performance on a memory-intensive subset of the SPEC CPU 2017 benchmarks by 3.78% for a single-core configuration, and by 11.4% for a 4-core configuration, compared to the baseline prefetcher alone

Serum th1 and th2 cytokines in systemic lupus erythematosus patients : its relationship with disease activity and organ involvement

Systemic lupus erythematosus (SLE) is a complex autoimmune disease that may result from defective functions of the immunoregulatory T cell circuits. Cytokines play an essential role in molding the quality of an immune response to foreign or self-antigens. With the growing literature regarding cytokine production in autoimmune diseases, an important role for an active Th 1 response, characterized by production of IFN-y, IL-2, fL- 12 and TNF-a has become evident. On the contrary, there have also been repeated observations of high levels of type 2 cytokines (IL-4, IL-5, IL-l 0, IL-6 and IL-13) particularly in the systemic autoimmune diseases. Objectives: To determine the circulating serum levels of two Th I (IL-2, IFN-y) and two Th2 (IL-6, IL-13) cytokines in patients with systemic lupus erythematosus (SLE), to compare serum level of IL-2, IFN- y, IL-6 and IL-13 with the disease activity in SLE patients and to assess the relationship between serum level of cytokines (IL-2, IL-6, lL- 13 and IFN-y) and different organ involvement in SLE patients. Methodology: We included 90 SLE patients and 30 healthy controls in this comparative cross sectional study carried out in Hospital Universiti Sains Malaysia (USM) and General Hospital Kota Bharu from October 2003 until September 2005 by selecting SLE patients in medical wards and outpatient clinics. Serum levels of cytokines were measured by ELISA (IL-2, interferon (IFN) y, IL-6 and IL-13) as well as antidsDNA, ANA, C3 and C4 complement levels were determined. Disease activity was recorded according to the Systemic Lupus Erythematosus Disease Activity Index(SLEDAI) and classified as high activity (SLEDAI > 8) or low activity (SLEDAI :S 8). Different organ affected at any time during the course of the disease was recorded. Results: The mean age of the patients was 31 .0± 10.8 years. Out of 90 SLE patients, 81 were females (90%) and 9 males (10%). Majority was Malay (92.2%) and the rest was Chinese (7.8%). 52 patients (57.8%) were inactive SLE (SLEDAI score 0-8) and 38 patients (42.2%) active SLE (SLEDAI score >8). Serum levels of cytokines in SLE patients were significantly higher than in healthy control with the exception of IL-2 (IFN' Y p<O.OO 1, IL-6 p<O.OO 1, IL-13 p=0.002, IL-2 p= 0.639). There were also significant differences between active and inactive SLE patients with the exception of IL-2 (IL-6 p <0.001 , IL-1 3 p = 0.009, IFN-y p <0.001and IL-2 p =0.087). There was a positive correlation between Th I (IFN- y) and Th2 (IL-6 and IL-1 3) cytokines with the disease activity ((IFN-y p=0.002, IL-6 p<O.OO 1, IL-1 3 p=0.006, IL-2 p= 0.151 ). There was significant correlation between serum level of IL-1 3 and musculoskeletal involvement (p =0.0 16) and also IL-6 with haematological involvement (p =0.003). Conclusion: The serum levels of Th2 (IL-6 and IL-1 3) and Th I (IFN- y) cytokines were significantly elevated and correlated with disease activity in SLE patients. Serum cytokine level could provide useful information about disease activity in SLE patients

Quality Assurance and Quality Control Correlations for the Dynamic Cone Penetrometer

The Dynamic Cone Penetrometer (DCP) is a device that is used for the estimation of in situ compaction quality of constructed subgrades and embankments. It is a relatively inexpensive, light-weight and easy to use device that measures the dynamic penetration resistance of the compacted soil, from which an estimate of soil strength and stiffness characteristics can be made. Owing to its ease of use, many DOTs in the U.S. have employed the DCP in their compaction quality control procedures, and over the past few decades, extensive research has been carried out on the development of correlations between the results of the DCP test and the results of strength and stiffness tests performed on compacted soils (e.g., California bearing ratio, and resilient modulus). The objectives of this research are to refine DCP-based quality assurance and quality control correlations for compaction quality control developed by previous research studies carried out at Purdue for the Indiana Department of Transportation, especially focusing on i) grouping of the soils based on their mechanical response to the DCP loading, and ii) limiting the in situ moisture range of the soils used for development of correlations within -2% of the optimum moisture content of the tested soil. The factors outlined above are studied, and in particular, soil grouping is examined critically. The AASHTO (`A-based\u27) classification employed previously for classification of soils is replaced by a new classification criteria specifically developed for the DCP test. Soils are grouped into one of the two categories of coarse-grained or fine-grained soils on the basis of the size of the dominant particle in the soil. The criteria developed for the classification of soil into one of these two categories is based on index properties of the soil, such as the standard Proctor maximum dry density, optimum moisture content, plasticity index (PI) and fines content (percentage passing 0.075 mm sieve size). For the purpose of refinement of the QA/QC correlations, extensive field and laboratory tests (more than 750 DCP tests) were carried out on soils found in Indiana to add to the existing database of DCP test results. The database was then statistically analyzed for extraction of the representative DCP test value (number of DCP blows required for a specific depth of penetration into the compacted soil) for different types of soil. Results show that the DCP test results for fine-grained soils have a good correlation with the PI, which is indicative of the clay content of the soil, while the DCP test results for coarse-grained soils have good correlations with the optimum moisture content of the soil, which is indicative of the targeted in situ density of the soil. Furthermore, a statistical analysis of the distribution of DCP blow counts in the field revealed that the mean of a minimum of 7 closely spaced tests is required to get a representative blow count of the compacted soil at a given location. More targeted testing is needed to assess the frequency of DCP testing required for larger areas

Madness Then, Insanity Now: The Evolution of Madness and Medicine in India from Ancient to Modern Times

My thesis will examine how madness and the medical systems that understood it have changed from ancient times to modern times in India. It begins with an examination of medicine in the Vedic era and considers the implications of a magico-religious epistemology that informed the treatment of madness in that time. From there, it moves on to the classical Ayurvedic systems of medicine and discusses the linkages and points of difference from the earlier system. In short, medicine generally becomes more empirically grounded, and madness is seen as having both somatic causes as well as external, “possession” causes. I then fast forward to the colonial era to focus on the development of the insane asylum under the British over the nineteenth century and the new authority relationships, power structures, and race relations that were implicated in the process. This is an especially crucial point in my thesis, and I spend many pages examining the topic because it is the first time that madness becomes institutionalized in the subcontinent. The next section moves on to the early twentieth century to understand how Ayurveda, dominant mostly in rural areas and long unrecognized by the colonial government, becomes resurrected for a modernized world and plays an important role in the debates around Indian nationalism. Finally, my last section uses anthropological sources to understand the nature of madness and its ties to kinship relations in contemporary India.Asian Studie