Accurate Force Field for Molybdenum by Machine Learning Large Materials Data

In this work, we present a highly accurate spectral neighbor analysis potential (SNAP) model for molybdenum (Mo) developed through the rigorous application of machine learning techniques on large materials data sets. Despite Mo's importance as a structural metal, existing force fields for Mo based on the embedded atom and modified embedded atom methods still do not provide satisfactory accuracy on many properties. We will show that by fitting to the energies, forces and stress tensors of a large density functional theory (DFT)-computed dataset on a diverse set of Mo structures, a Mo SNAP model can be developed that achieves close to DFT accuracy in the prediction of a broad range of properties, including energies, forces, stresses, elastic constants, melting point, phonon spectra, surface energies, grain boundary energies, etc. We will outline a systematic model development process, which includes a rigorous approach to structural selection based on principal component analysis, as well as a differential evolution algorithm for optimizing the hyperparameters in the model fitting so that both the model error and the property prediction error can be simultaneously lowered. We expect that this newly developed Mo SNAP model will find broad applications in large-scale, long-time scale simulations.Comment: 25 pages, 9 figure

Investigating the relationship between social support and durable return to work

The aim of the current study was to investigate the relationship between social support and durable return to work (RTW) post occupational injury. A total of 1,179 questionnaires were posted to clients previously receiving vocational rehabilitation services from the Return to Work Assist program in Queensland, Australia. Participants were asked to indicate their current RTW status, in addition to completing questionnaires measuring their relationship with their superior, relationships with colleagues, and social support external to the workplace. The statistical analysis included 110 participants. An ANOVA indicated that participants in the RTW group reported significantly better relationships with their superiors and colleagues than participants in the non-durable RTW group. No significant differences were observed between the RTW, non-durable RTW and no RTW groups on a measure of social support external to the workplace. Although the findings were limited by the low response rate, an evaluation of demographics indicated the respondents were representative of the original target sample. The findings suggested that providing support in the workplace is an important area for intervention and may be a means of increasing durable RTW outcomes.</jats:p

Optimizing the MapReduce Framework on Intel Xeon Phi Coprocessor

With the ease-of-programming, flexibility and yet efficiency, MapReduce has become one of the most popular frameworks for building big-data applications. MapReduce was originally designed for distributed-computing, and has been extended to various architectures, e,g, multi-core CPUs, GPUs and FPGAs. In this work, we focus on optimizing the MapReduce framework on Xeon Phi, which is the latest product released by Intel based on the Many Integrated Core Architecture. To the best of our knowledge, this is the first work to optimize the MapReduce framework on the Xeon Phi. In our work, we utilize advanced features of the Xeon Phi to achieve high performance. In order to take advantage of the SIMD vector processing units, we propose a vectorization friendly technique for the map phase to assist the auto-vectorization as well as develop SIMD hash computation algorithms. Furthermore, we utilize MIMD hyper-threading to pipeline the map and reduce to improve the resource utilization. We also eliminate multiple local arrays but use low cost atomic operations on the global array for some applications, which can improve the thread scalability and data locality due to the coherent L2 caches. Finally, for a given application, our framework can either automatically detect suitable techniques to apply or provide guideline for users at compilation time. We conduct comprehensive experiments to benchmark the Xeon Phi and compare our optimized MapReduce framework with a state-of-the-art multi-core based MapReduce framework (Phoenix++). By evaluating six real-world applications, the experimental results show that our optimized framework is 1.2X to 38X faster than Phoenix++ for various applications on the Xeon Phi

Hard Drive Heritage: Digital Cultural Property in the Law of Armed Conflict

This Note considers the question of how to protect cultural property in an era of rising cyberwarfare. The Note argues that the law of armed conflict (LOAC)—also referred to as international humanitarian law (IHL)— should apply to protect the three categories of cultural property which cyberwarfare could affect: real-word cultural property, digitized cultural property (cultural property which has been converted into digital form), and digital cultural property (cultural property which has always existed in digital form). Lastly, this Note argues for a novel interpretation of the 1954 Hague Convention for the Protection for Cultural Property that would encompass digital and digitized cultural property.

Emergency Wars

Passed in 1976, the National Emergencies Act ended 42-years of continuous national emergency, dating to 1933. Repealing four national emergencies, which allowed the president to draw on 470 emergency laws empowering him to run the nation "without reference to normal constitutional processes," the law instituted new procedures for exercising emergency authority, signifying a broader resurgence of congressional power in the 1970s. This thesis also examines the politics of presidential power, and how liberals became disillusioned with the presidency after Watergate and Vietnam, while the New Right gradually embraced executive authority to restrain the federal government and implement a hawkish foreign policy. The complex partisan and inter-branch politics of emergency powers fits into the broader distrust of government which pervaded the 1970s. This thesis explores the history of national emergencies in the 20th century United States, the legislative history of the National Emergencies Act, and American politics in the 1970s to elucidate the important role executive power plays in American politics.Bachelor of Art