Practical implementation and analysis of hyper-encryption

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 89-90).The security of modern cryptographic schemes relies on limits on computational power and assumptions about the difficulty of certain mathematical problems, such as integer factorization. This thesis describes hyper-encryption in the limited access model, a system that provides perfect secrecy and authentication against an adversary who possesses unbounded computational power, but who is limited in the ability to eavesdrop on more than a fraction of computers in a large network, such as the Internet. This thesis also presents an implementation of hyper-encryption in the limited access model, discusses areas where the theoretical system differs from the practical implementation, and analyzes their impact on the security of the system.by Jason K. Juang.M.Eng

Biology, Ecology, and Management of Nonnative Ambrosia Beetles (Coleoptera: Curculionidae: Scolytinae) in Ornamental Plant Nurseries

Xylosandrus germanus (Blandford) and Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae: Scolytinae) are two of the most damaging nonnative ambrosia beetle pests in ornamental plant nurseries. Adult females tunnel into the stems and branches of host plants to create galleries with brood chambers. Hosts are infected with symbiotic Ambrosiella spp. fungi that serve as food for the larvae and adults. Plants can also become infected with secondary opportunistic pathogens, including Fusarium spp. Both X. germanus and X. crassiusculus have broad host ranges, and infestations can result in “toothpicks” of extruded chewed wood and sap flow associated with gallery entrances, canopy dieback, stem and trunk cankers, and plant death. Beetles efficiently locate and preferentially attack living, weakened plants, especially those physiologically stressed by flooding, inadequate drainage, frost injury, or winter injury and low temperature. Maintaining plant health is the foundation of a management plan. Vulnerable hosts can be partially protected with preventive pyrethroid applications in the spring before peak flight and attack, which are monitored using ethanol-based trapping tactics

Growing impact of wildfire on western US water supply

Streamflow often increases after fire, but the persistence of this effect and its importance to present and future regional water resources are unclear. This paper addresses these knowledge gaps for the western United States (WUS), where annual forest fire area increased by more than 1,100% during 1984 to 2020. Among 72 forested basins across the WUS that burned between 1984 and 2019, the multibasin mean streamflow was significantly elevated by 0.19 SDs (P 20% of forest area burned in a year, streamflow over the first 6 water years postfire increased by a multibasin average of 0.38 SDs, or 30%. Postfire streamflow increases were significant in all four seasons. Historical fire–climate relationships combined with climate model projections suggest that 2021 to 2050 will see repeated years when climate is more fire-conducive than in 2020, the year currently holding the modern record for WUS forest area burned. These findings center on relatively small, minimally managed basins, but our results suggest that burned areas will grow enough over the next 3 decades to enhance streamflow at regional scales. Wildfire is an emerging driver of runoff change that will increasingly alter climate impacts on water supplies and runoff-related risks

Isotherm data for adsorption of amoxicillin, ampicillin, and doripenem onto bentonite

The dataset reported in this article describes the adsorption isotherms of amoxicillin, ampicillin, and doripenem onto bentonite. Batch adsorption experiments were carried out on single antibiotic solutions with various dosage of bentonite across temperatures from 30 to 50 °C. The adsorbent loading dataset was later obtained by measuring the concentration of antibiotic solution at adsorption equilibrium via UV-Vis spectrophotometer. The dataset was also fitted using various isotherm models including Freundlich, Langmuir, Toth, Hill, and Dubinin-Radushkevich models to further analyze the adsorption behavior. On top of that, orthogonal regression was applied to avoid fitting biasness, whereby the fitting results revealed the highest adsorption capacities of 82.259 mg g−1 for amoxicillin, 78.851 mg g−1 for ampicillin, and 93.278 mg g−1 for doripenem using Langmuir model, which gave an accurate representation of the adsorption isotherm dataset that was consistent with the results of Toth and Hill model

The use of acoustic indices to determine avian species richness in audio-recordings of the environment

Interpreting acoustic recordings of the natural environment is an increasingly important technique for ecologists wishing to monitor terrestrial ecosystems. Technological advances make it possible to accumulate many more recordings than can be listened to or interpreted, thereby necessitating automated assistance to identify elements in the soundscape. In this paper we examine the problem of estimating avian species richness by sampling from very long acoustic recordings. We work with data recorded under natural conditions and with all the attendant problems of undefined and unconstrained acoustic content (such as wind, rain, traffic, etc.) which can mask content of interest (in our case, bird calls). We describe 14 acoustic indices calculated at one minute resolution for the duration of a 24 hour recording. An acoustic index is a statistic that summarizes some aspect of the structure and distribution of acoustic energy and information in a recording. Some of the indices we calculate are standard (e.g. signal-to-noise ratio), some have been reported useful for the detection of bioacoustic activity (e.g. temporal and spectral entropies) and some are directed to avian sources (spectral persistence of whistles). We rank the one minute segments of a 24 hour recording in descending order according to an "acoustic richness" score which is derived from a single index or a weighted combination of two or more. We describe combinations of indices which lead to more efficient estimates of species richness than random sampling from the same recording, where efficiency is defined as total species identified for given listening effort. Using random sampling, we achieve a 53% increase in species recognized over traditional field surveys and an increase of 87% using combinations of indices to direct the sampling. We also demonstrate how combinations of the same indices can be used to detect long duration acoustic events (such as heavy rain and cicada chorus) and to construct long duration (24 h) spectrograms

Synthesis of Sustainable Circular Economy in Palm Oil Industry Using Graph-Theoretic Method

Huge generation of oil palm biomass has stimulated the development of biorefineries for synthesis of bioproducts. By targeting the palm oil industry and the biorefineries as the consumers of these products, a sustainable circular economy can be created by recycling the biomass wastes to the said consumers. To evaluate the techno-economic feasibility of the sustainable circular economy, a mathematical model demonstrating the biomass network with consideration of recycling is developed in this work. Besides, Process Graph (P-graph) is incorporated to perform the combinatorial optimization of the biomass network, which targets three common resources: fertilizer, steam, and electricity for regeneration and recycling. Although the result shows that the linear economy model is preferred in terms of profitability, the circular economy model shows potential in reducing 39.292% of the imported steam and 13.469% of the imported electricity, while being 0.642% lower in terms of the gross profit. Three scenarios are then proposed to identify the potential bottleneck that can hinder the implementation of the sustainable circular economy approach, with the aid of sensitivity analysis. This work is expected to benefit the biomass-based industry sectors and the policymakers on future development and transition to the sustainable circular economy

2-DE combined with two-layer feature selection accurately establishes the origin of oolong tea

Taiwan is known for its high quality oolong tea. Because of high consumer demand, some tea manufactures mix lower quality leaves with genuine Taiwan oolong tea in order to increase profits. Robust scientific methods are, therefore, needed to verify the origin and quality of tea leaves. In this study, we investigated whether two-dimensional gel electrophoresis (2-DE) and nanoscale liquid chromatography/tandem mass spectroscopy (nano-LC/MS/MS) coupled with a two-layer feature selection mechanism comprising information gain attribute evaluation (IGAE) and support vector machine feature selection (SVM-FS) are useful in identifying characteristic proteins that can be used as markers of the original source of oolong tea. Samples in this study included oolong tea leaves from 23 different sources. We found that our method had an accuracy of 95.5% in correctly identifying the origin of the leaves. Overall, our method is a novel approach for determining the origin of oolong tea leaves