# Physical Sciences and Mathematics Commons™

## All Articles in Physical Sciences and Mathematics

160007 full-text articles. Page 1 of 4016.

In Operando Mechanism Analysis On Nanocrystalline Silicon Anode Material For Reversible And Ultrafast Sodium Storage, 2018 University of Wollongong

#### 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 ...

2018 Harvey Mudd College

#### Iterative Matrix Factorization Method For Social Media Data Location Prediction, Natchanon Suaysom

##### HMC Senior Theses

Since some of the location of where the users posted their tweets collected by social media company have varied accuracy, and some are missing. We want to use those tweets with highest accuracy to help fill in the data of those tweets with incomplete information. To test our algorithm, we used the sets of social media data from a city, we separated them into training sets, where we know all the information, and the testing sets, where we intentionally pretend to not know the location. One prediction method that was used in (Dukler, Han and Wang, 2016) requires appending one-hot ...

Recursive Non-Local Means Filter For Video Denoising, 2017 University of Dayton

#### Recursive Non-Local Means Filter For Video Denoising, Redha A. Ali, Russell C. Hardie

##### Electrical and Computer Engineering Faculty Publications

In this paper, we propose a computationally efficient algorithm for video denoising that exploits temporal and spatial redundancy. The proposed method is based on non-local means (NLM). NLM methods have been applied successfully in various image denoising applications. In the single-frame NLM method, each output pixel is formed as a weighted sum of the center pixels of neighboring patches, within a given search window.

The weights are based on the patch intensity vector distances. The process requires computing vector distances for all of the patches in the search window. Direct extension of this method from 2D to 3D, for video ...

Cybercrime Deterrence And International Legislation: Evidence From Distributed Denial Of Service Attacks, 2017 Singapore Management University

#### 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 ...

2017 The Graduate Center, City University of New York

#### Asymptotic Counting Formulas For Markoff-Hurwitz Tuples, Ryan Ronan

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

The Markoff equation is a Diophantine equation in 3 variables first studied in Markoff's celebrated work on indefinite binary quadratic forms. We study the growth of solutions to an n variable generalization of the Markoff equation, which we refer to as the Markoff-Hurwitz equation. We prove explicit asymptotic formulas counting solutions to this generalized equation with and without a congruence restriction. After normalizing and linearizing the equation, we show that all but finitely many solutions appear in the orbit of a certain semigroup of maps acting on finitely many root solutions. We then pass to an accelerated subsemigroup of ...

2017 The Graduate Center, City University of New York

#### Some Results In Combinatorial Number Theory, Karl Levy

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

The first chapter establishes results concerning equidistributed sequences of numbers. For a given $d\in\mathbb{N}$, $s(d)$ is the largest $N\in\mathbb{N}$ for which there is an $N$-regular sequence with $d$ irregularities. We compute lower bounds for $s(d)$ for $d\leq 10000$ and then demonstrate lower and upper bounds $\left\lfloor\sqrt{4d+895}+1\right\rfloor\leq s(d)< 24801d^{3} + 942d^{2} + 3$ for all $d\geq 1$. In the second chapter we ask if $Q(x)\in\mathbb{R}[x]$ is a degree $d$ polynomial such that for $x\in[x_k]=\{x_1,\cdots,x_k\}$ we have $|Q(x)|\leq 1$, then how big can its lead coefficient be? We prove that there is a unique polynomial, which we call $L_{d,[x_k]}(x)$, with maximum lead coefficient under these constraints and construct an algorithm that generates $L_{d,[x_k]}(x)$.

Developing Grounded Goals Through Instant Replay Learning, 2017 Swarthmore College

#### Developing Grounded Goals Through Instant Replay Learning, Lisa Meeden, Douglas S. Blank

##### Computer Science Faculty Research and Scholarship

This paper describes and tests a developmental architecture that enables a robot to explore its world, to find and remember interesting states, to associate these states with grounded goal representations, and to generate action sequences so that it can re-visit these states of interest. The model is composed of feed-forward neural networks that learn to make predictions at two levels through a dual mechanism of motor babbling for discovering the interesting goal states and instant replay learning for developing the grounded goal representations. We compare the performance of the model with grounded goal representations versus random goal representations, and find ...

A Weighted Möbius Function, 2017 Portland State University

#### A Weighted Möbius Function, Derek Garton

##### Mathematics and Statistics Faculty Publications and Presentations

Fix an odd prime ℓ and let G be the poset of isomorphism classes of finite abelian ℓ-groups, ordered by inclusion. If ξ:G→R≥0 is a discrete probability distribution on G and A ∈ G, define the Ath moment of ξ to be . The question of determining conditions that ensure ξ is completely determined by its moments has been of recent interest in many problems of Cohen–Lenstra type. Furthermore, recovering ξ from its moments requires a new Möbius-type inversion formula on G. In this paper, we define this function, relate it to the classical Möbius function ...

Investigation Into The Formation Of Information Security Influence: Network Analysis Of An Emerging Organisation, 2017 RMIT University

#### Investigation Into The Formation Of Information Security Influence: Network Analysis Of An Emerging Organisation, Duy Dang-Pham, Siddhi Pittayachawan, Vince Bruno

##### Siddhi Pittayachawan

While prior research has been examining information security behaviours in mature environments with formal policies and practices, there is less attention paid to new or transforming environments that lack security controls. It is crucial to understand what factors affect the formation of an emerging information security environment, so that security managers can make use of the forming mechanisms to improve the security environment without relying too much on enforcement. This research adopts exponential random graph modeling to predict the occurrence of information security influence among 114 employees in a recently established construction organisation. Our empirical findings show that physically co-locating ...

2017 The University of San Francisco

#### Rethinking Urban Green Infrastructure As A Means To Promote Avian Conservation, Allen Lau

##### Master's Projects and Capstones

There is an under-recognized potential for cities to use urban green infrastructure to contribute to avian biodiversity conservation. At the global scale, climate change and growing urbanization are primary global drivers leading to decline and homogenization in world bird populations. Birds are fundamental and intricate species in ecosystems, and even in urban areas, act as indicator and regulator species contributing to healthy ecosystem function. While many cities have recognized the economic and social benefits associated with green spaces, such as the vast benefits ecosystem services provide to the urban dweller, the use of green spaces to concurrently contribute to avian ...

Comparison Of Visual Datasets For Machine Learning, 2017 Purdue University

#### Comparison Of Visual Datasets For Machine Learning, Kent Gauen, Ryan Dailey, John Laiman, Yuxiang Zi, Nirmal Asokan, Yung-Hsiang Lu, George K. Thiruvathukal, Mei-Ling Shyu, Shu-Ching Chen

##### Computer Science: Faculty Publications and Other Works

One of the greatest technological improvements in recent years is the rapid progress using machine learning for processing visual data. Among all factors that contribute to this development, datasets with labels play crucial roles. Several datasets are widely reused for investigating and analyzing different solutions in machine learning. Many systems, such as autonomous vehicles, rely on components using machine learning for recognizing objects. This paper compares different visual datasets and frameworks for machine learning. The comparison is both qualitative and quantitative and investigates object detection labels with respect to size, location, and contextual information. This paper also presents a new ...

Vertex Weighted Spectral Clustering, 2017 East Tennessee State University

#### Vertex Weighted Spectral Clustering, Mohammad Masum

##### Electronic Theses and Dissertations

Spectral clustering is often used to partition a data set into a specified number of clusters. Both the unweighted and the vertex-weighted approaches use eigenvectors of the Laplacian matrix of a graph. Our focus is on using vertex-weighted methods to refine clustering of observations. An eigenvector corresponding with the second smallest eigenvalue of the Laplacian matrix of a graph is called a Fiedler vector. Coefficients of a Fiedler vector are used to partition vertices of a given graph into two clusters. A vertex of a graph is classified as unassociated if the Fiedler coefficient of the vertex is close to ...

2017 University of Southern Mississippi

#### Synthesis And Catalytic Evaluation Of Novel C-Alpha-Methyl-Beta-Proline Analogues, And Concise Synthetic Approach To Nh-Fmoc-S-Trityl-C-Alpha-Methyl Cysteine, Hari Kiran Kotapati

##### Dissertations

In the field of chemistry there is a growing demand for small molecule organocatalysts such as amino acids, more specifically proline and its analogues, which could catalyze various key chemical reactions in the synthesis of several biologically important molecules. Even though natural proline is reported to catalyze various chemical reactions, its use as organocatalyst is limited mainly due to the solubility issues in the reaction media and high catalyst loadings, which is not very ideal for bulk scale manufacturing. To address these limitations we planned to develop unnatural analogues of proline that could catalyze the reactions with lower catalyst loadings ...

Report Of The Chemist., 2017 Iowa State College

#### Report Of The Chemist., G. E. Patrick

##### Bulletin (Iowa Agricultural Experiment Station)

At the request of the Director three samples were taken from the Russian Thistle plat on as many different dates, two weeks apart, and submitted to chemical analysis. The samples were taken by cutting within half an inch of the ground; the “heights” reported below are from measurement of the samples after cutting.

Socioeconomic Status, Air Quality And Geographic Variation In Emergency Room Visits For Acute Bronchitis On The California Central Coast, 2017 California Polytechnic State University

#### Socioeconomic Status, Air Quality And Geographic Variation In Emergency Room Visits For Acute Bronchitis On The California Central Coast, Sean Lang-Brown, Heather W. Starnes, Gary B. Hughes

##### Symposium

IMPORTANCE: Analysis of geospatial variation in acute bronchitis due to socioeconomic and environmental factors can allow the efficient delivery of resources to populations most at risk.

OBJECTIVE: We sought to determine if small scale variation in socioeconomic factors and emergency room (ER) visits for acute bronchitis are associated in small cities or rural communities. We also modeled the effects of air quality on daily rates of ER visits for acute bronchitis in the context of socioeconomic factors to investigate modifying relationships.

DESIGN, SETTING, AND PARTICIPANTS: We examined ER visits for acute bronchitis in San Luis Obispo and Santa Barbara counties ...

An Analysis Of The Application Of Simplified Silhouette To The Evaluation Of K-Means Clustering Validity, 2017 Dublin Institute of Technology

#### An Analysis Of The Application Of Simplified Silhouette To The Evaluation Of K-Means Clustering Validity, Hector-Hugo Franco-Penya, John D. Kelleher, John Pugh, Robert Ross

##### Conference papers

Silhouette is one of the most popular and effective internal measures for the evaluation of clustering validity. Simplified Silhouette is a computationally simplified version of Silhouette. However, to date Simplified Silhouette has not been systematically analysed in a specific clustering algorithm. This paper analyses the application of Simplified Silhouette to the evaluation of k-means clustering validity and compares it with the k-means Cost Function and the original Silhouette from both theoretical and empirical perspectives. The theoretical analysis shows that Simplified Silhouette has a mathematical relationship with both the k-means Cost Function and the original Silhouette, while empirically, we show that ...

2017 California State University, Monterey Bay

#### 2015 – Project Justification – Addressing An Urgent Water Supply Need For A Disadvantaged Community In The Greater Monterey County Irwm Region

##### Miscellaneous Monterey and San Luis Obispo County Documents and Reports

One hundred percent of Castroville’s water supply comes from the 400-foot aquifer of the Pressure sub-basin of the Salinas Valley Groundwater Basin. Groundwater levels in the aquifer dropped more than 100 feet below the seal level as of July 2015 at static conditions. Water levels dropped to more than 190 feet below the mean sea level during operation of the water well. The dramatic drop combined with the close proximity of the Pacific Ocean (less than 4 miles) and to existing seawater intrusion (less than ¼ mile) raised significant alarm that the existing water supply system to Castroville was ...

Effect Of Treatment And Cultivar On The Ensiling Of Corn Stover, 2017 United States Department of Agriculture

#### Effect Of Treatment And Cultivar On The Ensiling Of Corn Stover, R. E. Muck, J. G. Coors, T. L. Richard, M. P. Scott

##### M. Paul Scott

Nine cultivars of corn stover selected for ethanol potential were harvested (34 to 40% dry matter) and each ensiled with six treatments: untreated, lactic acid bacteria, cell-wall degrading enzymes, sulfuric acid, bacteria-enzyme combination and enzyme-acid combination. Ensiling was carried out in vacuum-sealed bags at ~22°C for 60 d. The untreated stovers ensiled well. Lactic acid bacteria and enzyme treatments had no effect on pH, but the bacteria-enzyme combination lowered pH in some cultivars. The acid and acid-enzyme treatments had low pH values ranging from 1.3 to 1.5. Lactic acid was generally highest in the bacteria-enzyme treatment whereas ...

2017 California State University, Monterey Bay

#### 2013, November 19 - Protective Elevations To Control Sea Water Intrusion In The Salinas Valley, Geoscience For Mcwra

##### Miscellaneous Monterey and San Luis Obispo County Documents and Reports

A report prepared in support of preventing revocation of Permit 1043 (State of California Division of Water Rights Permit for Diversion of Use of Water – Amended Permit 11043 dated 110-Jul-49) that allows for appropriation of water from the Salinas River in Monterey County California not to exceed 400 cfs with annual maximum diversion not to exceed 168,538 acre feet per year. The report addresses the potential beneficial uses of diverting water to help increase groundwater levels in the Pressure and East Side Subareas that would in turn help to control seawater intrusion.

2017 California State University, Monterey Bay

#### 2015, November - Salinas River Salt Modeling Report , Tetra Tech For California Central Coast Regional Water Quality Control Board And Us Environmental Protection Agency, Region Ix

##### State and Federal Documents Relating to Monterey and San Luis Obispo Counties

Report prepared by Tetra Tech on behalf of California Central Coast Regional Water Quality Control Board and US Environmental Protection Agency, Region IX with a view of development of salt-related TMDLs and a salt and nutrient management plan for the Salinas Valley aquifers. The report provides data analysis and a literature review, development of a water and salt mass balance tool, and salt sources assessment. Recommendations regarding improved representation of cropland locations, rotations, and irrigation practices are provided.