Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1 - 30 of 152444

Full-Text Articles in Physical Sciences and Mathematics

Real Analysis I, Ismail Nikoufar Dec 2105

Real Analysis I, Ismail Nikoufar

Ismail Nikoufar

Real Analysis slides for my graduate students.


Effect Of Head Group Size On The Photoswitching Applications Of Azobenzene Disperse Red 1 Analogues, Chris Corkery, Alexis Goulet-Hanssens, Arri Priimagi, Christopher Barrett Dec 2103

Effect Of Head Group Size On The Photoswitching Applications Of Azobenzene Disperse Red 1 Analogues, Chris Corkery, Alexis Goulet-Hanssens, Arri Priimagi, Christopher Barrett

Chris Corkery

No abstract provided.


Gram Scale Synthesis Of The C(1)-C(9) Fragment Of Amphidinolide C, Nicholas A Morra, Brian L Pagenkopf Oct 2103

Gram Scale Synthesis Of The C(1)-C(9) Fragment Of Amphidinolide C, Nicholas A Morra, Brian L Pagenkopf

Chemistry Publications

An allylic cis-epoxide prepared by Sharpless asymmetric epoxidation was transformed in 9 steps and 41% overall yield to the cyclization precursor 4 via a key one carbon homologation. Cobalt catalyzed aerobic oxidative cyclization of 4 gave the trans-THF in 94% yield at gram scale. Subsequent manipulations, including a Still-Gennari olefination, Sharpless asymmetric dihydroxylation, Corey-Fuchs alkynylation and Kazmaier hydrostannylation provided the fully functionalized C(1)-C(9) fragment 2 suitable for cross coupling. The sequence is readily scalable and provides gram quantities of 2


In Operando Mechanism Analysis On Nanocrystalline Silicon Anode Material For Reversible And Ultrafast Sodium Storage, Lei Zhang, Xianluo Hu, Chaoji Chen, Haipeng Guo, Xiaoxiao Liu, Gengzhao Xu, Haijian Zhong, Shuang Cheng, Peng Wu, Jiashen Meng, Yunhui Huang, Shi Xue Dou, Hua-Kun Liu Mar 2018

In Operando Mechanism Analysis On Nanocrystalline Silicon Anode Material For Reversible And Ultrafast Sodium Storage, Lei Zhang, Xianluo Hu, Chaoji Chen, Haipeng Guo, Xiaoxiao Liu, Gengzhao Xu, Haijian Zhong, Shuang Cheng, Peng Wu, Jiashen Meng, Yunhui Huang, Shi Xue Dou, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

Presently, lithium-ion batteries (LIBs) are the most promising commercialized electrochemical energy storage systems. Unfortunately, the limited resource of Li results in increasing cost for its scalable application and a general consciousness of the need to find new type of energy storage technologies. Very recently, substantial effort has been invested to sodium-ion batteries (SIBs) due to their effectively unlimited nature of sodium resources. Furthermore, the potential of Li/Li+ is 0.3 V lower than that of Na/Na+, which makes it more effective to limit the electrolyte degradation on the outer surface of the electrode.[1] Nevertheless, one major obstacle ...


Cybercrime Deterrence And International Legislation: Evidence From Distributed Denial Of Service Attacks, Kai-Lung Hui, Seung Hyun Kim, Qiu-Hong Wang Dec 2017

Cybercrime Deterrence And International Legislation: Evidence From Distributed Denial Of Service Attacks, Kai-Lung Hui, Seung Hyun Kim, Qiu-Hong Wang

Research Collection School Of Information Systems

In this paper, we estimate the impact of enforcing the Convention on Cybercrime (COC) on deterring distributed denial of service (DDOS) attacks. Our data set comprises a sample of real, random spoof-source DDOS attacks recorded in 106 countries in 177 days in the period 2004-2008. We find that enforcing the COC decreases DDOS attacks by at least 11.8 percent, but a similar deterrence effect does not exist if the enforcing countries make a reservation on international cooperation. We also find evidence of network and displacement effects in COC enforcement. Our findings imply attackers in cyberspace are rational, motivated by ...


Elimination For Systems Of Algebraic Differential Equations, Richard Gustavson Jun 2017

Elimination For Systems Of Algebraic Differential Equations, Richard Gustavson

All Graduate Works by Year: Dissertations, Theses, and Capstone Projects

We develop new upper bounds for several effective differential elimination techniques for systems of algebraic ordinary and partial differential equations. Differential elimination, also known as decoupling, is the process of eliminating a fixed subset of unknown functions from a system of differential equations in order to obtain differential algebraic consequences of the original system that do not depend on that fixed subset of unknowns. A special case of differential elimination, which we study extensively, is the question of consistency, that is, if the given system of differential equations has a solution. We first look solely at the ``algebraic data" of ...


Mechanistic Mathematical Models: An Underused Platform For Hpv Research, Marc Ryser, Patti Gravitt, Evan R. Myers Jun 2017

Mechanistic Mathematical Models: An Underused Platform For Hpv Research, Marc Ryser, Patti Gravitt, Evan R. Myers

Global Health Faculty Publications

Health economic modeling has become an invaluable methodology for the design and evaluation of clinical and public health interventions against the human papillomavirus (HPV) and associated diseases. At the same time, relatively little attention has been paid to a different yet complementary class of models, namely that of mechanistic mathematical models. The primary focus of mechanistic mathematical models is to better understand the intricate biologic mechanisms and dynamics of disease. Inspired by a long and successful history of mechanistic modeling in other biomedical fields, we highlight several areas of HPV research where mechanistic models have the potential to advance the ...


Compact Dual-Band Bandpass Filter Based On Fractal Stub-Loaded Resonator, Hadi T. Ziboon, Jawad K. Ali May 2017

Compact Dual-Band Bandpass Filter Based On Fractal Stub-Loaded Resonator, Hadi T. Ziboon, Jawad K. Ali

Professor Jawad K. Ali

Fractal geometries have shown to be a suitable choice for the antenna and microwave circuit designers to produce compact size microwave devices and components. Moreover, the multimode resonators are found advantageous in the design of reduced size multiband bandpass filters. In this paper, a stub loaded resonator (SLR) based on modified Minkowski fractal geometry, is suggested to produce a compact microstrip bandpass filter with dual-band response for wireless communication applications. Based on the second iteration Minkowski fractal geometry, dual-band compact microstrip BPF has been presented. The proposed filter structure is composed of two fractal based symmetrical SLRs. The filter structure ...


Compact Dual-Mode Microstrip Band Reject Filter Based On Koch Fractal Geometry, Hayder S. Ahmed, Ali J. Salim, Jawad K. Ali May 2017

Compact Dual-Mode Microstrip Band Reject Filter Based On Koch Fractal Geometry, Hayder S. Ahmed, Ali J. Salim, Jawad K. Ali

Professor Jawad K. Ali

In this paper, a new fractal-based microstrip dual-mode band stop filter (BSF) has been
presented. The proposed filter structure is mainly based on that of the triangular patch resonators
with an embedded slit structure. The Koch fractal geometry has been applied to the uncoupled side
lengths of the triangular patch resonator. The filter structure has been modeled, and its performance
is evaluated using the commercially available EM simulator, Sonnet. Results reveal that the
resulting dual-mode response depends heavily on the uncoupled side lengths of the triangular patch
resonator. A parametric study has been conducted to explore the effect of the ...


A Compact Dual-Band Slot Antenna Based On Koch Fractal Snowflake Annular Ring, Mahmood T. Yassen, Mohammed R. Hussan, Hussain A. Hammas, Hussam Al-Saedi, Jawad K. Ali May 2017

A Compact Dual-Band Slot Antenna Based On Koch Fractal Snowflake Annular Ring, Mahmood T. Yassen, Mohammed R. Hussan, Hussain A. Hammas, Hussam Al-Saedi, Jawad K. Ali

Professor Jawad K. Ali

This paper presents the design of a compact dual-band slot antenna for use in the
recently available wireless communication applications. The slot structure of the proposed antenna
is based on an annular slot-ring with Koch snowflake fractal geometry of the third iteration. The
antenna slot structure has been etched on the ground plane of a substrate with relative permittivity
of 4.5 and 1.524 mm thickness. On the other side of the substrate, a 50-Ohm microstrip line has
been etched as the antenna feed structure. The proposed antenna has a compact size of (40 × 40 ×
1.524) mm3. Simulation ...


Roman Domination In Complementary Prisms, Alawi I. Alhashim May 2017

Roman Domination In Complementary Prisms, Alawi I. Alhashim

Electronic Theses and Dissertations

The complementary prism GG of a graph G is formed from the disjoint union of G and its complement G by adding the edges of a perfect match- ing between the corresponding vertices of G and G. A Roman dominating function on a graph G = (V,E) is a labeling f : V(G) → {0,1,2} such that every vertex with label 0 is adjacent to a vertex with label 2. The Roman domination number γR(G) of G is the minimum f(V ) = Σv∈V f(v) over all such functions of G. We study the Roman domination number ...


Sustainability Education In Primary And Secondary Schools: Great Needs And Possible Solutions, Allison Watson May 2017

Sustainability Education In Primary And Secondary Schools: Great Needs And Possible Solutions, Allison Watson

University of Tennessee Honors Thesis Projects

No abstract provided.


Heterogeneity Of Avian Breeding Habitat On Grazing Lands Of The Northern Great Plains, Maggi S. Sliwinski May 2017

Heterogeneity Of Avian Breeding Habitat On Grazing Lands Of The Northern Great Plains, Maggi S. Sliwinski

Dissertations & Theses in Natural Resources

Native rangelands in the Great Plains are largely privately owned and used for beef production. Vegetation heterogeneity is important for maintaining biodiversity, but private land may be more homogenous than desired. My research had two components: 1) to examine whether a variety of grazing strategies created vegetation heterogeneity in a large, intact rangeland, and 2) to understand beef producers’ attitudes about vegetation heterogeneity.

First, I sampled vegetation structure, composition, and bird abundance at multiple plots on eleven management units in Cherry County, Nebraska. Units were managed with commonly used grazing strategies (e.g., short-duration grazing and season-long continuous grazing). I ...


A Distribution Of The First Order Statistic When The Sample Size Is Random, Vincent Z. Forgo Mr May 2017

A Distribution Of The First Order Statistic When The Sample Size Is Random, Vincent Z. Forgo Mr

Electronic Theses and Dissertations

Statistical distributions also known as probability distributions are used to model a random experiment. Probability distributions consist of probability density functions (pdf) and cumulative density functions (cdf). Probability distributions are widely used in the area of engineering, actuarial science, computer science, biological science, physics, and other applicable areas of study. Statistics are used to draw conclusions about the population through probability models. Sample statistics such as the minimum, first quartile, median, third quartile, and maximum, referred to as the five-number summary, are examples of order statistics. The minimum and maximum observations are important in extreme value theory. This paper will ...


Synthesis And In-Vitro Cell Viability/Cytotoxicity Studies Of Novel Pyrrolobenzodiazepine Derivatives, John M. Jarrett May 2017

Synthesis And In-Vitro Cell Viability/Cytotoxicity Studies Of Novel Pyrrolobenzodiazepine Derivatives, John M. Jarrett

Undergraduate Honors Theses

Pyrrolobenzodiazepines (PBDs) are a group of naturally occurring compounds that were discovered in the cultures of Streptomyces in the 1960s. Some natural PBDs discovered in these cultures, such as anthramycin and sibiromycin, were shown to possess a broad spectrum of anti-tumor activity. Since cancer is still a leading cause of death globally, the development of novel anti-proliferative derivatives of PBDs is essential for human welfare worldwide. Further synthesis and structure-activity relationship (SAR) studies of the parent natural products and their tetracyclic analogs will lead to the discovery of drug candidates. In this work, thirteen PBD analogues were synthesized using no ...


Effect Of Chain Rigidity On Network Architecture And Deformation Behavior Of Glassy Polymer Networks, Kyler Reser Knowles May 2017

Effect Of Chain Rigidity On Network Architecture And Deformation Behavior Of Glassy Polymer Networks, Kyler Reser Knowles

Dissertations

Processing carbon fiber composite laminates creates molecular-level strains in the thermoset matrix upon curing and cooling which can lead to failures such as geometry deformations, micro-cracking, and other issues. It is known strain creation is attributed to the significant volume and physical state changes undergone by the polymer matrix throughout the curing process, though storage and relaxation of cure-induced strains remain poorly understood. This dissertation establishes two approaches to address the issue. The first establishes testing methods to simultaneously measure key volumetric properties of a carbon fiber composite laminate and its polymer matrix. The second approach considers the rigidity of ...


Extensible Energy Planning Framework For Preemptive Tasks, Jin Hyun Kim, Deepak Gangadharan, Oleg Sokolsky, Axel Legay, Insup Lee May 2017

Extensible Energy Planning Framework For Preemptive Tasks, Jin Hyun Kim, Deepak Gangadharan, Oleg Sokolsky, Axel Legay, Insup Lee

Departmental Papers (CIS)

Cyber-physical systems (CSPs) are demanding energy-efficient design not only of hardware (HW), but also of software (SW). Dynamic Voltage and and Frequency Scaling (DVFS) and Dynamic Power Manage (DPM) are most popular techniques to improve the energy efficiency. However, contemporary complicated HW and SW designs requires more elaborate and sophisticated energy management and efficiency evaluation techniques. This paper is concerned about energy supply planning for real-time scheduling systems (units) of which tasks need to meet deadlines. This paper presents a modelbased compositional energy planning technique that computes a minimal ratio of processor frequency that preserves schedulability of independent and preemptive ...


Recommender Response To Diversity And Popularity Bias In User Profiles, Sushma Channamsetty, Michael D. Ekstrand Apr 2017

Recommender Response To Diversity And Popularity Bias In User Profiles, Sushma Channamsetty, Michael D. Ekstrand

Michael D. Ekstrand

Recommender system evaluation usually focuses on the overall effectiveness of the algorithms, either in terms of measurable accuracy or ability to deliver user satisfaction or improve business metrics. When additional factors are considered, such as the diversity or novelty of the recommendations, the focus typically remains on the algorithm’s overall performance. We examine the relationship of the recommender’s output characteristics – accuracy, popularity (as an inverse of novelty), and diversity – to characteristics of the user’s rating profile. The aims of this analysis are twofold: (1) to probe the conditions under which common algorithms produce more or less diverse ...


Osspal: Finding And Evaluating Open Source Software, Anthony Wasserman Apr 2017

Osspal: Finding And Evaluating Open Source Software, Anthony Wasserman

Tony Wasserman

This paper describes the OSSpal project, which is aimed at helping companies, government agencies, and other organizations find high quality free and open source software (FOSS) that meets their needs. OSSpal is a successor to the Business Readiness Rating (BRR), combining quantitative and qualitative evaluation measures for software in various categories. Instead of a purely numeric calculated score OSSpal adds curation of high-quality FOSS projects and individual user reviews of these criteria. Unlike the BRR project, for which there was no automated support, OSSpal has an operational, publicly available website where users may search by project name or category, and ...


Pine Needle Pyrolysis: Bio-Waste Into Biofuel, Alexandra Fuentes Apr 2017

Pine Needle Pyrolysis: Bio-Waste Into Biofuel, Alexandra Fuentes

Scholarly & Creative Works Conference 2017

This project explores the alternate uses of biomass. In particular, it focuses on pine needles as a source for biofuels. Pine needles are of interest because in certain Mountain communities they are collected and removed from residential properties. By removing the pine needles, communities create a “defensible space” to prevent wild fires from destroying homes. These needles are often placed in regional landfills. The South Tahoe Refuse and Recycling Services alone has more than 4,340 tons of pine needles dumped at their facility annually. This large amount of biomass can be a potential energy source.

The focus of this ...


Dynamic Secondary Electron Emission In Dielectric/Conductor Mixed Coatings, Leandro Olano, Isabel Montero, María E. Dávila, Jr Dennison Apr 2017

Dynamic Secondary Electron Emission In Dielectric/Conductor Mixed Coatings, Leandro Olano, Isabel Montero, María E. Dávila, Jr Dennison

Presentations

An unexpected behavior of the Secondary Emission Yield (SEY) on coatings composed by a mixture of conductor and dielectric microparticles was reported and modeled in [1]. As a follow up, we measured for a fixed primary energy the dynamic evolution of the SEY in similar samples and proposed a charging-roughness coupled model to simulate the experimental results. Two different coatings were selected: 1) TMM and Al microparticles (type 1), and 2) zeolites and gold nanoparticles (type 2). Pulsed and continuous tests were used to obtain the SEY as a function of the primary energy.

In both types of samples extremely ...


Magnetic Massive Stars As Progenitors Of ‘Heavy’ Stellar-Mass Black Holes, V. Petit, Z. Keszthelyi, R. Macinnis, David H. Cohen, R. H. D. Townsend, G. A. Wade, S. L. Thomas, S. P. Owocki, J. Puls, A. Ud-Doula Apr 2017

Magnetic Massive Stars As Progenitors Of ‘Heavy’ Stellar-Mass Black Holes, V. Petit, Z. Keszthelyi, R. Macinnis, David H. Cohen, R. H. D. Townsend, G. A. Wade, S. L. Thomas, S. P. Owocki, J. Puls, A. Ud-Doula

Physics & Astronomy Faculty Works

The groundbreaking detection of gravitational waves produced by the inspiralling and coalescence of the black hole (BH) binary GW150914 confirms the existence of ‘heavy’ stellar-mass BHs with masses >25 M⊙. Initial characterization of the system by Abbott et al. supposes that the formation of BHs with such large masses from the evolution of single massive stars is only feasible if the wind mass-loss rates of the progenitors were greatly reduced relative to the mass-loss rates of massive stars in the Galaxy, concluding that heavy BHs must form in low-metallicity (Z ≲ 0.25-0.5 Z⊙) environments. However, strong surface magnetic fields ...


Eassistant: Cognitive Assistance For Identification And Auto-Triage Of Actionable Conversations, Hamid R. Motahari Nezhad, Kalpa Gunaratna, Juan Cappi Apr 2017

Eassistant: Cognitive Assistance For Identification And Auto-Triage Of Actionable Conversations, Hamid R. Motahari Nezhad, Kalpa Gunaratna, Juan Cappi

Kno.e.sis Publications

The browser and screen have been the main user interfaces of the Web and mobile apps. The notification mechanism is an evolution in the user interaction paradigm by keeping users updated without checking applications. Conversational agents are posed to be the next revolution in user interaction paradigms. However, without intelligence on the triage of content served by the interaction and content differentiation in applications, interaction paradigms may still place the burden of information overload on users. In this paper, we focus on the problem of intelligent identification of actionable information in the content served by applications, and in particular in ...


Diverse Stellar Haloes In Nearby Milky Way Mass Disc Galaxies., Benjamin Harmsen, Antonela Monachesi, Eric F. Bell, Roelof S. De Jong, Jeremy Bailin, David J. Radburn-Smith, Benne W. Holwerda Apr 2017

Diverse Stellar Haloes In Nearby Milky Way Mass Disc Galaxies., Benjamin Harmsen, Antonela Monachesi, Eric F. Bell, Roelof S. De Jong, Jeremy Bailin, David J. Radburn-Smith, Benne W. Holwerda

Faculty Scholarship

We have examined the resolved stellar populations at large galactocentric distances along the minor axis (from 10 kpc up to between 40 and 75 kpc), with limited major axis coverage, of six nearby highly inclined MilkyWay (MW) mass disc galaxies using Hubble Space Telescope data from the Galaxy haloes, Outer discs, Substructure, Thick discs, and Star clusters (GHOSTS) survey. We select red giant branch stars to derive stellar halo density profiles. The projected minor axis density profiles can be approximated by power laws with projected slopes of −2 to −3.7 and a diversity of stellar halo masses of 1 ...


Automatic Verification Of Finite Precision Implementations Of Linear Controllers, Junkil Park, Miroslav Pajic, Oleg Sokolsky, Insup Lee Apr 2017

Automatic Verification Of Finite Precision Implementations Of Linear Controllers, Junkil Park, Miroslav Pajic, Oleg Sokolsky, Insup Lee

Departmental Papers (CIS)

We consider the problem of verifying finite precision implementation of linear time-invariant controllers against mathematical specifications. A specification may have multiple correct implementations which are different from each other in controller state representation, but equivalent from a perspective of input-output behavior (e.g., due to optimization in a code generator). The implementations may use finite precision computations (e.g. floating-point arithmetic) which cause quantization (i.e., roundoff) errors. To address these challenges, we first extract a controller's mathematical model from the implementation via symbolic execution and floating-point error analysis, and then check approximate input-output equivalence between the extracted model ...


Vcat: Dynamic Cache Management Using Cat Virtualization, Meng Xu, Linh T.X. Phan, Hyon-Young Choi, Insup Lee Apr 2017

Vcat: Dynamic Cache Management Using Cat Virtualization, Meng Xu, Linh T.X. Phan, Hyon-Young Choi, Insup Lee

Departmental Papers (CIS)

This paper presents vCAT, a novel design for dynamic shared cache management on multicore virtualization platforms based on Intel’s Cache Allocation Technology (CAT). Our design achieves strong isolation at both task and VM levels through cache partition virtualization, which works in a similar way as memory virtualization, but has challenges that are unique to cache and CAT. To demonstrate the feasibility and benefits of our design, we provide a prototype implementation of vCAT, and we present an extensive set of microbenchmarks and performance evaluation results on the PARSEC benchmarks and synthetic workloads, for both static and dynamic allocations. The ...


Resilient Linear Classification: An Approach To Deal With Attacks On Training Data, Sangdon Park, James Weimer, Insup Lee Apr 2017

Resilient Linear Classification: An Approach To Deal With Attacks On Training Data, Sangdon Park, James Weimer, Insup Lee

Departmental Papers (CIS)

Data-driven techniques are used in cyber-physical systems (CPS) for controlling autonomous vehicles, handling demand responses for energy management, and modeling human physiology for medical devices. These data-driven techniques extract models from training data, where their performance is often analyzed with respect to random errors in the training data. However, if the training data is maliciously altered by attackers, the effect of these attacks on the learning algorithms underpinning data-driven CPS have yet to be considered. In this paper, we analyze the resilience of classification algorithms to training data attacks. Specifically, a generic metric is proposed that is tailored to measure ...


An Exploratory Study Of Fifth-Grade Students’ Reasoning About The Relationship Between Fractions And Decimals When Using Number Line-Based Virtual Manipulatives, Scott Smith Apr 2017

An Exploratory Study Of Fifth-Grade Students’ Reasoning About The Relationship Between Fractions And Decimals When Using Number Line-Based Virtual Manipulatives, Scott Smith

All Graduate Theses and Dissertations

Understanding the relationship between fractions and decimals is an important step in developing an overall understanding of rational numbers. Research has demonstrated the feasibility of technology in the form of virtual manipulatives for facilitating students’ meaningful understanding of rational number concepts. This exploratory dissertation study was conducted for the two closely related purposes: first, to investigate a sample of fifth-grade students’ reasoning regarding the relationship between fractions and decimals for fractions with terminating decimal representations while using virtual manipulative incorporating parallel number lines; second, to investigate the affordances of the virtual manipulatives for supporting the students’ reasoning about the decimal-fraction ...


Real-Time Vision-Based Lane Detection With 1d Haar Wavelet Transform On Raspberry Pi, Vikas Reddy Sudini Apr 2017

Real-Time Vision-Based Lane Detection With 1d Haar Wavelet Transform On Raspberry Pi, Vikas Reddy Sudini

All Graduate Theses and Dissertations

Rapid progress is being made towards the realization of autonomous cars. Since the technology is in its early stages, human intervention is still necessary in order to ensure hazard-free operation of autonomous driving systems. Substantial research efforts are underway to enhance driver and passenger safety in autonomous cars. Toward that end GreedyHaarSpiker, a real-time vision-based lane detection algorithm is proposed for road lane detection in different weather conditions. The algorithm has been implemented in Python 2.7 with OpenCV 3.0 and tested on a Raspberry Pi 3 Model B ARMv8 1GB RAM coupled to a Raspberry Pi camera board ...


Identity-Based Data Outsourcing With Comprehensive Auditing In Clouds, Yujue Wang, Qianhong Wu, Bo Qin, Wenchang Shi, Deng, Robert H., Jiankun Hu Apr 2017

Identity-Based Data Outsourcing With Comprehensive Auditing In Clouds, Yujue Wang, Qianhong Wu, Bo Qin, Wenchang Shi, Deng, Robert H., Jiankun Hu

Research Collection School Of Information Systems

Cloud storage system provides facilitative file storage and sharing services for distributed clients. To address integrity, controllable outsourcing, and origin auditing concerns on outsourced files, we propose an identity-based data outsourcing (IBDO) scheme equipped with desirable features advantageous over existing proposals in securing outsourced data. First, our IBDO scheme allows a user to authorize dedicated proxies to upload data to the cloud storage server on her behalf, e.g., a company may authorize some employees to upload files to the company's cloud account in a controlled way. The proxies are identified and authorized with their recognizable identities, which eliminates ...