Using Process Algebra to Statically Analyze Incremental Propagation Graphs

Active Operations are a set of operations that can be composed to build incremental bidirectional OCL-like expressions on collections. Each operation is capable of updating its result (resp. source) when a change occurs on its source (resp. result). The current implementation of active operations relies on the Observer design pattern to propagate changes from each operation to its successors. These relations form an implicit directed acyclic propagation graph. Previous work showed that this approach is limited and alignment issues appear in some situations. Several workarounds were proposed to mitigate these issues. In this work we present a new relational notation to describe propagation graphs. Along with this notation, we also present a new static analysis method of the propagation graph based on process algebra. This new method enables optimizations of the propagation graph not achievable with previous approaches, such as detection of parallelizable sections of the propagation graph or cache optimizations in specific situation

GraphX: Unifying Data-Parallel and Graph-Parallel Analytics

From social networks to language modeling, the growing scale and importance of graph data has driven the development of numerous new graph-parallel systems (e.g., Pregel, GraphLab). By restricting the computation that can be expressed and introducing new techniques to partition and distribute the graph, these systems can efficiently execute iterative graph algorithms orders of magnitude faster than more general data-parallel systems. However, the same restrictions that enable the performance gains also make it difficult to express many of the important stages in a typical graph-analytics pipeline: constructing the graph, modifying its structure, or expressing computation that spans multiple graphs. As a consequence, existing graph analytics pipelines compose graph-parallel and data-parallel systems using external storage systems, leading to extensive data movement and complicated programming model. To address these challenges we introduce GraphX, a distributed graph computation framework that unifies graph-parallel and data-parallel computation. GraphX provides a small, core set of graph-parallel operators expressive enough to implement the Pregel and PowerGraph abstractions, yet simple enough to be cast in relational algebra. GraphX uses a collection of query optimization techniques such as automatic join rewrites to efficiently implement these graph-parallel operators. We evaluate GraphX on real-world graphs and workloads and demonstrate that GraphX achieves comparable performance as specialized graph computation systems, while outperforming them in end-to-end graph pipelines. Moreover, GraphX achieves a balance between expressiveness, performance, and ease of use

Panel discussion: Proposals for improving OCL

During the panel session at the OCL workshop, the OCL community discussed, stimulated by short presentations by OCL experts, potential future extensions and improvements of the OCL. As such, this panel discussion continued the discussion that started at the OCL meeting in Aachen in 2013 and on which we reported in the proceedings of the last year's OCL workshop. This collaborative paper, to which each OCL expert contributed one section, summarises the panel discussion as well as describes the suggestions for further improvements in more detail.Peer ReviewedPostprint (published version

Veterans’ Medical Care: FY2016 Appropriations

[Excerpt] The Department of Veterans Affairs (VA) provides benefits to veterans who meet certain eligibility criteria. Benefits to veterans range from disability compensation and pensions to hospital and medical care. The VA provides these benefits through three major operating units: the Veterans Health Administration (VHA), the Veterans Benefits Administration (VBA), and the National Cemetery Administration (NCA). This report focuses on funding for the VHA

Assembling and enriching digital library collections

People who create digital libraries need to gather together the raw material, add metadata as necessary, and design and build new collections. This paper sets out the requirements for these tasks and describes a new tool that supports them interactively, making it easy for users to create their own collections from electronic files of all types. The process involves selecting documents for inclusion, coming up with a suitable metadata set, assigning metadata to each document or group of documents, designing the form of the collection in terms of document formats, searchable indexes, and browsing facilities, building the necessary indexes and data structures, and putting the collection in place for others to use. Moreover, different situations require different workflows, and the system must be flexible enough to cope with these demands. Although the tool is specific to the Greenstone digital library software, the underlying ideas should prove useful in more general contexts

MS-235: LTC Richard F. Pendleton ‘63 Papers

The collection includes maps, photographs, documents, and correspondence related to the service of LTC Richard F. Pendleton ’63 and the Vietnam War. These include detailed maps and items highlighting aspects of Pendleton’s time in Vietnam and broader pieces regarding different aspects of the Vietnam War era. Much of this correspondence is in the form of e-mails written many years after the war, and thus includes the personal opinions and biases of their authors. The printed articles included in the collection were also selected by Pendleton and reflect his interests and opinions on the war and its aftermath; they are not necessarily sources original to the Vietnam War era. The collection includes deep information on and discussions of Pendleton’s advisory team and its operations in Vietnam as a major strength, though it may not be as useful for those seeking first-hand information of those who served in different types of units and organizations. Potential research interests include the work of MACV Advisory Teams, intelligence operations in Vietnam, and veterans’ perspectives on the war. This collection includes some graphic content in Binder 1-2, most notably images of dead Viet Cong soldiers. Special Collections and College Archives Finding Aids are discovery tools used to describe and provide access to our holdings. Finding aids include historical and biographical information about each collection in addition to inventories of their content. More information about our collections can be found on our website https://www.gettysburg.edu/special-collections/collections/.https://cupola.gettysburg.edu/findingaidsall/1200/thumbnail.jp

A graphical user interface for Boolean query specification

On-line information repositories commonly provide keyword search facilities via textual query languages based on Boolean logic. However, there is evidence to suggest that the syntactical demands of such languages can lead to user errors and adversely affect the time that it takes users to form queries. Users also face difficulties because of the conflict in semantics between AND and OR when used in Boolean logic and English language. We suggest that graphical query languages, in particular Venn-like diagrams, can alleviate the problems that users experience when forming Boolean expressions with textual languages. We describe Vquery, a Venn-diagram based user interface to the New Zealand Digital Library (NZDL). The design of Vquery has been partly motivated by analysis of NZDL usage. We found that few queries contain more than three terms, use of the intersection operator dominates and that query refinement is common. A study of the utility of Venn diagrams for query specification indicates that with little or no training users can interpret and form Venn-like diagrams which accurately correspond to Boolean expressions. The utility of Vquery is considered and directions for future work are proposed

Using Your Library’s Objectives as the Organizational Framework for Library Documentation in Planning, Assessment, and Accreditation

The San Diego Christian/Southern California Seminary Library1 uses its objectives as the organizational framework for its strategic plan, annual report, assessment plan, and policies and procedures manual. This article describes how the library’s objectives compare to the Association of College and Research Libraries’ Standards (to ensure best practices), relate to the areas covered in the library strategic plan, annual report, and operations manual, and correspond to the standards and criteria from their respective accrediting agencies, showing how easy it is to identify supporting evidence for a program review or self-study when using this organizing method