Physical Sciences and Mathematics Commons^™

Efficient Oblivious Transfers With Access Control, Jinguang Han, Willy Susilo, Yi Mu, Jun Yan

Professor Yi Mu

Oblivious transfer (OT) is a protocol where a receiver can obtain t-out-of-n services from the sender without releasing anything about his choices. OT can be used to protect user’s privacy. In principle, any user can interact with a server to request some services. This might allow some undesirable users to obtain services from the server. How to ensure that only the authorized receivers can obtain services obliviously is a daunting task. In this paper, we introduce oblivious signature based-on envelope (OSBE) to OT and propose two novel OT schemes, which only allow the legitimate receivers to obtain services obliviously. The …

Attribute-Based Oblivious Access Control, Jinguang Han, Willy Susilo, Yi Mu, Jun Yan

Professor Yi Mu

In an attribute-based system (ABS), users are identified by various attributes, instead of their identities. Since its seminal introduction, the attribute-based mechanism has attracted a lot of attention. However, current ABS schemes have a number of drawbacks: (i) the communication cost is linear in the number of the required attributes; (ii) the computation cost is linear in the number of the required attributes and (iii) there are no efficient verification algorithms for the secret keys. These drawbacks limit the use of ABS in practice. In this paper, we propose an attribute-based oblivious access control (ABOAC) scheme to address these problems, …

Analysis Of Property-Preservation Capabilities Of The Rox And Esh Hash Domain Extenders, Reza Reyhanitabar, Willy Susilo, Yi Mu

Professor Yi Mu

Two of the most recent and powerful multi-property preserving (MPP) hash domain extension transforms are the Ramdom-Oracle-XOR (ROX) transform and the Enveloped Shoup (ESh) transform. The former was proposed by Andreeva et al. at ASIACRYPT 2007 and the latter was proposed by Bellare and Ristenpart at ICALP 2007. In the existing literature, ten notions of security for hash functions have been considered in analysis of MPP capabilities of domain extension transforms, namely CR, Sec, aSec, eSec (TCR), Pre, aPre, ePre, MAC, PRF, PRO. Andreeva et al. showed that ROX is able to preserve seven properties; namely collision resistance (CR), three …

Identity-Based Traitor Tracing With Short Private Key And Short Ciphertext, Fuchun Guo, Yi Mu, Willy Susilo

Professor Yi Mu

Identity-based traitor tracing (IBTT) scheme can be utilized to identify a private (decryption) key of any identity that is illegally used in an identity-based broadcast encryption scheme. In PKC'07, Abdalla et al. proposed the first IBTT construction with short private key. In CCS'08, Boneh and Naor proposed a public-key traitor tracing, which can be extended to IBTT with short ciphertext. With a further exploration, in this paper, we propose the first IBTT with short private key and short ciphertext. Private key and ciphertext are both order of O(l 1+l 2), where l 1 is the bit length of codeword of …

Practical Compact E-Cash, Man Ho Au, Willy Susilo, Yi Mu

Professor Yi Mu

Compact e-cash schemes allow a user to withdraw a wallet containing k coins in a single operation, each of which the user can spend unlinkably. One big open problem for compact e-cash is to allow multiple denominations of coins to be spent efficiently without executing the spend protocol a number of times. In this paper, we give a (partial) solution to this open problem by introducing two additional protocols, namely, compact spending and batch spending. Compact spending allows spending all the k coins in one operation while batch spending allows spending any number of coins in the wallet in a …

Fixed Rank Filtering For Spatio-Temporal Data, Noel Cressie, Tao Shi, Emily L. Kang

Professor Noel Cressie

Datasets from remote-sensing platforms and sensor networks are often spatial, temporal, and very large. Processing massive amounts of data to provide current estimates of the (hidden) state from current and past data is challenging, even for the Kalman filter. A large number of spatial locations observed through time can quickly lead to an overwhelmingly high-dimensional statistical model. Dimension reduction without sacrificing complexity is our goal in this article. We demonstrate how a Spatio-Temporal Random Effects (STRE) component of a statistical model reduces the problem to one of fixed dimension with a very fast statistical solution, a methodology we call Fixed …

Combining Outputs From The North American Regional Climate Change Assessment Program By Using A Bayesian Hierarchical Model, Emily L. Kang, Noel Cressie, Stephan R. Sain

Professor Noel Cressie

We investigate the 20-year-average boreal winter temperatures generated by an ensemble of six regional climate models (RCMs) in phase I of the North American Regional Climate Change Assessment Program. We use the long-run average (20-year integration) to smooth out variability and to capture the climate properties from the RCM outputs. We find that, although the RCMs capture the large-scale climate variation from coast to coast and from south to north similarly, their outputs can differ substantially in some regions. We propose a Bayesian hierarchical model to synthesize information from the ensemble of RCMs, and we construct a consensus climate signal …

Modeling Dynamic Controls On Ice Streams: A Bayesian Statistical Approach, L Mark Berliner, Kenneth Jezek, Noel Cressie, Yongku Kim, Calvin Lam, Cornelis Van Der Veen

Professor Noel Cressie

Our main goal is to exemplify the study of ice-stream dynamics via Bayesian statistical analysis incorporating physical, though imperfectly known, models using data that are both incomplete and noisy. The physical-statistical models we propose account for these uncertainties in a coherent, hierarchical manner. The initial modeling assumption estimates basal shear stress as equal to driving stress, but subsequently includes a random corrector process to account for model error. The resulting stochastic equation is incorporated into a simple model for surface velocities. Use of Bayes' theorem allows us to make inferences on all unknowns given basal elevation, surface elevation and surface …

A Method For Evaluating Bias In Global Measurements Of Co2 Total Columns From Space, D Wunch, P O. Wennberg, G C. Toon, B J. Connor, B Fisher, G B. Osterman, C Frankenberg, L Mandrake, C O'Dell, P Ahonen, S C. Biraud, R Castano, Noel Cressie, D Crisp, N M. Deutscher, A Eldering, M L. Fisher, David W. Griffith, M Gunson, P Heikkinen, G Keppel-Aleks, E Kyro, R Lindemaier, Ronald Macatangay, J Mendonca, J Messerschmidt, C E. Miller, I Morino, J Notholt, F A. Oyafuso, M Rettinger, J Robinson, C M. Roehl, R J. Salawitch, V Sherlock, K Strong, R Sussmann, T Tanaka, D R. Thompson, O Uchino, Thorsten Warneke, Steven C. Wofsy

Professor Noel Cressie

We describe a method of evaluating systematic errors in measurements of total column dry-air mole fractions of CO2 (XCO2) from space, and we illustrate the method by applying it to the v2.8 Atmospheric CO2 Observations from Space retrievals of the Greenhouse Gases Observing Satellite (ACOS-GOSAT) measurements over land. The approach exploits the lack of large gradients in XCO2 south of 25S to identify large-scale offsets and other biases in the ACOS-GOSAT data with several retrieval parameters and errors in instrument calibration. We demonstrate the effectiveness of the method by comparing the ACOS-GOSAT data in the Northern Hemisphere with ground truth …

Dynamical Random-Set Modeling Of Concentrated Precipitation In North America, Noel Cressie, Renato Assuncao, Scott H. Holan, Michael Levine, Orietta Nicolis, Jun Zhang, Jian Zou

Professor Noel Cressie

In order to study climate at scales where policy decisions can be made, regional climate models (RCMs) have been developed with much finer resolution (~50 km) than the ~500 km resolution of atmosphere-ocean general circulation models (AOGCMs). The North American Regional Climate Change Assessment Program (NARCCAP) is an international program that provides 50-km resolution climate output for the United States, Canada, and northern Mexico. In Phase I, there are six RCMs, from which we choose one to illustrate our methodology. The RCMs are updated every 3 hours and contain a number of variables, including temperature, precipitation, wind speed, wind direction, …

Rejoinder, Peter Craigmile, Catherine Caldert, Hongfei Li, Rajib Paul, Noel Cressie

Professor Noel Cressie

We agree with Schmidt that it is essential that researchers from many diverse areas have access to affordable, but still trustworthy, software. In this research project, substantial effort went into preparing datasets. Much of the data came from different government agencies, with databases arranged in multiple formats, often including variables that were not immediately relevant to our scientific pursuits. In our work on this project, the use of SAS was essential to producing clean datasets.

Hierarchical Model Building, Fitting, And Checking: A Behind-The-Scenes Look At A Bayesian Analysis Of Arsenic Exposure Pathways, Peter F. Craigmile, Catherine A. Calder, Hongfei Li, Rajib Paul, Noel Cressie

Professor Noel Cressie

In this article, we present a behind-the-scenes look at a Bayesian hierarchical analysis of pathways of exposure to arsenic (a toxic heavy metal) using the Phase I National Human Exposure Assessment Survey carried out in Arizona. Our analysis combines individual-level personal exposure measurements (biomarker and environmental media) with water, soil, and air observations from the ambient environment. We include details of our model-building exercise that involved a combination of exploratory data analysis and substantive knowledge in exposure science. Then we present our strategies for model fitting, which involved piecing together components of the hierarchical model in a systematic fashion to …

Accounting For Uncertainty In Ecological Analysis: The Strengths And Limitations Of Hierarchical Statistical Modeling, Noel Cressie, Catherine Calder, James Clark, Jay Ver Hoef, Christopher Wikle

Professor Noel Cressie

Analyses of ecological data should account for the uncertainty in the process(es) that generated the data. However, accounting for these uncertainties is a difficult task, since ecology is known for its complexity. Measurement and/or process errors are often the only sources of uncertainty modeled when addressing complex ecological problems, yet analyses should also account for uncertainty in sampling design, in model specification, in parameters governing the specified model, and in initial and boundary conditions. Only then can we be confident in the scientific inferences and forecasts made from an analysis. Probability and statistics provide a framework that accounts for multiple …

Spectral Density Estimation Through A Regularized Inverse Problem, Chunfeng Huang, Tailen Hsing, Noel Cressie

Professor Noel Cressie

In the study of stationary stochastic processes on the real line, the covariance function and the spectral density function are parameters of considerable interest. They are equivalent ways of expressing the temporal dependence in the process. In this article, we consider the spectral density function and propose a new estimator that is not based on the periodogram; the estimator is derived through a regularized inverse problem. A further feature of the estimator is that the data are not required to be observed on a grid. When the regularization condition is based on the function's first derivative, we give the estimator …

Designing A Culturally Specific E-Learning Website, Penelope Mcfarlane

Dr Penelope McFarlane

Western Universities have delivered subjects via a variety of means for years. Although business has explored the concept of different cultures requiring different interfaces on their web sites; little has been done to explore the impact of culture on e-learning. This paper explores the development of culturally specific e-learning web sites based in Australia but being delivered in Dubai. The theories of Geert Hofstede were used to explore the culture of Dubai. The web construct was based on St Amant’s work on culturally specific web sites. Computer science students were then surveyed to determine their reaction to the culturally specific …

Multi-Year Lags Between Forest Browning And Soil Respiration At High Northern Latitudes, Ben Bond-Lamberty, Andrew Godard Bunn, Allison M. Thomson

Environmental Sciences Faculty and Staff Publications

High-latitude northern ecosystems are experiencing rapid climate changes, and represent a large potential climate feedback because of their high soil carbon densities and shifting disturbance regimes. A significant carbon flow from these ecosystems is soil respiration (RS, the flow of carbon dioxide, generated by plant roots and soil fauna, from the soil surface to atmosphere), and any change in the high-latitude carbon cycle might thus be reflected in RSobserved in the field. This study used two variants of a machine-learning algorithm and least squares regression to examine how remotely-sensed canopy greenness (NDVI), climate, and other variables are …

Collaborative Research: North East Cyberinfrastructure Consortium, Michael Eckardt

University of Maine Office of Research Administration: Grant Reports

EPS-0918284, University of Vermont & State Agricultural College, J. L. Van Houten, linked to EPS-0918033 (University of New Hampshire), EPS-0918078 (University of Delaware), EPS-0918018 (University of Maine), EPS-0918061 (University of Rhode Island)
Collaborative Research: North East Cyberinfrastructure Consortium

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

The North East Cyberinfrastructure Consortium (NECC) unites Maine (ME), New Hampshire (NH), Vermont (VT), Rhode Island (RI), and Delaware (DE) to support cyber-enabled research that requires analyses of large datasets. The project is organized around sharing resources, expertise and facilities in order to make cyber-enabled collaborative …

Energetyczne Wykorzystanie Stałych Paliw Wtórnych Z Odpadów (Srf) Na Przykładzie Instalacji Współspalania Paliw W Cementowni Chełm, Magdalena Kasietczuk, Robert Oleniacz

Robert Oleniacz

The paper presents the use of Solid Recovered Fuels (SRF) in Chelm Cement Plant (Poland). These types of fuels are produced from non-hazardous waste and can be used for energy recovery in waste co-combustion plants. They are much cheaper compared to primary fuels, so their use in the process of cement clinker burning brings evident economic benefits. Chelm cement plant owned by the CEMEX company is a leader in the use of alternative fuels in Poland. In the years 2005-2011 the amount of co-combustion of alternative fuels in the cement had risen from 107 to 318 thousand tons, and their …

Statistical Inference When Using Data Adaptive Estimators Of Nuisance Parameters, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

In order to be concrete we focus on estimation of the treatment specific mean, controlling for all measured baseline covariates, based on observing n independent and identically distributed copies of a random variable consisting of baseline covariates, a subsequently assigned binary treatment, and a final outcome. The statistical model only assumes possible restrictions on the conditional distribution of treatment, given the covariates, the so called propensity score. Estimators of the treatment specific mean involve estimation of the propensity score and/or estimation of the conditional mean of the outcome, given the treatment and covariates. In order to make these estimators asymptotically …

Treatment Selections Using Risk-Benefit Profiles Based On Data From Comparative Randomized Clinical Trials With Multiple Endpoints, Brian Claggett, Lu Tian, Davide Castagno, L. J. Wei

Harvard University Biostatistics Working Paper Series

No abstract provided.

Slides: Proposed Statewide Baseline Groundwater Sampling And Monitoring Rules, University Of Colorado Boulder. Natural Resources Law Center, Colorado. Oil And Gas Conservation Commission

Monitoring and Protecting Groundwater During Oil and Gas Development (November 26)

Presenter: Kathryn Mutz, Natural Resources Law Center, University of Colorado Law School

16 slides

Towards Sequence-Based Dna Flexibility Analysis, Emily Flynn, Filip Jagodzinski, Ileana Streinu

Computer Science: Faculty Publications

In this poster, we present an extension to our freely available KINARI-Web server to identify rigid and flexible regions of nucleic acids and protein-nucleic acid complexes contained in the Protein Data Bank (PDB). The goal is to explore the effect of DNA and RNA on the rigidity and stability of these structures. We also propose an approach for determining DNA rigidity based solely on sequence. Currently, only the rigidity of DNA molecules whose structures have been deposited in the PDB (approx. <4,000 files) can be analyzed. Once fine-tuned and validated, this new coordinate-free method for investigating DNA flexibility could be applied to the more than 135 million sequences in GenBank, and to nanostructure design.

Preparation Of Nitrogen-Containing Heterocycles Via Cyclization Of Pyridine-Tethered Organolithiums, Elizabeth Archer

Master's Theses

No abstract provided.

Towards Biophysical Validation Of Constraint Modeling For Rigidity Analysis Of Proteins, Filip Jagodzinski, Ileana Streinu

Computer Science: Faculty Publications

Proteins are dynamic molecules, and understanding how they flex and bend provides fundamental insights to their functions. Methods such as molecular dynamics are computationally expensive, and can simulate protein motions on limited timescales. Rigidity analysis is an alternative method, in which a protein structure is analyzed to infer which portions of the molecule are flexible. To perform rigidity analysis, a model is first constructed in which various inter-atomic stabilizing interactions are modeled according to their strength. No detailed study has been conducted as to what is the most plausible, chemically validated modeling scheme. All previous implementations have relied on heuristics, …

Variability Of Pennsylvanian-Permian Carbonate Associations And Implications For Nw Pangea Palaeogeography, East-Central British Columbia, Canada, K. D. Zubin-Stathopoulos, B. Beauchamp, V. I. Davydov, C. M. Henderson

Geosciences Faculty Publications and Presentations

Different stages of Pennsylvanian-Permian carbonate sedimentation in east-central British Columbia record a complex history of changing environments influenced by evolving palaeogeography and climate. Newly recognized tectonically controlled features affected the distribution and variability of carbonate associations, providing new interpretations for this portion of the west coast of Pangea. Both a heterozoan (cool water) and photozoan (warm-water) association were identified on either side of a palaeogeographic high here informally termed “Tipinahokan Peninsula”. Cool water carbonates were located outboard, or to the west of this high, an area influenced by upwelling waters. Inboard of this high, a warm, protected sea developed, here …

Analyzing Utilization Rates In Data Centers For Optimizing Energy Management, Michael Pawlish, Aparna Varde, Stefan Robila

Department of Computer Science Faculty Scholarship and Creative Works

In this paper, we explore academic data center utilization rates from an energy management perspective with the broader goal of providing decision support for green computing. The utilization rate is defined as the overall extent to which data center servers are being used and is usually recorded as a percentage. Recent literature states that utilization rates at many data centers are quite low resulting in poor usage of resources such as energy and labor. Based on our study we attribute these lower utilization rates to not fully taking advantage of virtualization and cloud technology. This paper describes our research including …

Controlled Degradation Of Poly(Ester Amide)S Via Cyclization Of Pendant Functional Groups, Jose Samuel Mejia

Electronic Thesis and Dissertation Repository

Polyesters have been used for many biomedical applications ranging from sutures to drug delivery vehicles. However, their bulk degradation results in an accumulation of acidic byproducts, which is detrimental to the human body. In order to circumvent this problem, as well as to impart new properties and functions to polymers for biomedical applications, poly(ester amide)s (PEAs) have been proposed as a different class of biodegradable polymers. However, up to date, there exists no way to stimulate the degradation of these polymers.

The Gillies research group has previously incorporated self-immolative spacers into polymers and has been able to stimulate their degradation …

Agenda: Monitoring And Protecting Groundwater During Oil And Gas Development, University Of Colorado Boulder. Natural Resources Law Center. Intermountain Oil And Gas Bmp Project, Colorado Water And Energy Research Center

Monitoring and Protecting Groundwater During Oil and Gas Development (November 26)

This workshop is cosponsored by the Intermountain Oil and Gas BMP Project and the Colorado Water and Energy Research Center, with financial support from the Environmentally Friendly Drilling Project and the CU-Boulder Outreach Committee.

The Colorado Oil and Gas Conservation Commission (COGCC) recently initiated a rule making process to develop new, statewide regulations for baseline sampling and monitoring of groundwater near new oil and gas wells. COGCC’s first rule making hearing was held November 14; the rule is expected to be finalized December 10. This workshop will discuss oil and gas development procedures that can impact groundwater, the current rules …

Slides: Survey Of State Sampling And Monitoring Rules, Kathryn Mutz, Josh Kruger

Monitoring and Protecting Groundwater During Oil and Gas Development (November 26)

Presenters: Kathryn Mutz and Josh Kruger, Natural Resources Law Center, University of Colorado Law School

7 slides

Slides: Routes To Sustainability: Natural Gas Development And Air And Water Resources In The Rocky Mountain Region, Mark Williams

Monitoring and Protecting Groundwater During Oil and Gas Development (November 26)

Presenter: Mark Williams, University of Colorado Boulder

14 slides