A Novel Framework for Model Checking UDP Network Interactions

This poster presents the first Java Pathfinder extension to model realistic User Datagram Protocol (UDP) networking communications, which is used to verify a UDP network software simulator, RF. Java Pathfinder is a model checking software system developed by NASA and used frequently for verifying that concurrent software systems avoid deadlock states and other errors. It does not natively support network modeling. NetIOCache is a Java Pathfinder extension for verifying TCP/IP networks, but no similar UDP extensions currently exist. NetStub, a Java Pathfinder extension, can simulate UDP behavior as a collection of threads, but it does not simulate important and common UDP properties such as packet loss and reordering that are often necessary to simulate in order to verify a UDP network model. I present a novel extension to Java Pathfinder to allow modeling of realistic UDP communications that includes simulated packet loss and reordering. This extension is then used to verify RF for up to four network processes. The RF model is verified accurate (it never encounters deadlocks or uncaught Java exceptions)

On Divestment

Foreword to On Divestment The writings collected here are an online supplement to a class zine title On Divestment. The zine and online archive were conceived, written, and designed by the members of the Spring 2015 Literature and Environment course (ENGL 374) at the University of Puget Sound. Considerations of timeliness and sustainability encouraged us to keep the size of the printed zine compact by including only excerpts of each author’s work; the zine is in a sense an advertisement for the more substantial body of writing that you find here on Sound Ideas, which reproduces student creative work in its entirety. Informed by our study of works of ecocriticism such as Rob Nixon’s Slow Violence and the Environmentalism of the Poor (Harvard UP, 2011), which explores the role that imaginative writing can play in illuminating ecological issues, our class seized the opportunity of a collaborative final project to see how students’ own writing—whether creative, critical, or some combination of the two—might engage with a topical environmental concern. The selection of a final project was arrived at through a democratic process. Working in groups of five individuals, students presented proposals for a final project, arguing both for the primacy of the environmental concern they selected and the efficacy of the writing task they were asking the class to undertake. All the proposals were excellent, but the class had to settle on a single undertaking; the project that students ultimately selected was the fossil fuel divestment movement, currently a topic of debate on many university campuses, including the University of Puget Sound. Largely led by students, this ongoing environmental movement encourages colleges and universities to divest their endowment holdings from companies whose primary business is fossil fuel. Since we knew from recent reportage in The Trail that UPS’s own ECO Club is advocating for fossil fuel divestment, we invited ECO Club representatives to speak to the class. From their visit, we learned about the broad contours of the divestment movement. Observing that the majority of scientists understand anthropogenic climate change to be the result of burning fossil fuels, the divestment movement argues that colleges and universities should exert pressure on these companies by withdrawing their investments from them. Several universities have already made commitments to divest some component of their endowment, among them Stanford University, Pitzer College, and the University of Glasgow, and campaigns to do so are underway at other institutions of higher learning, as well as many cities and municipalities. In formalizing the class proposal into an assignment, the terms were intentionally crafted to remain open-ended and non-prescriptive. Students were invited simply “to create a work of literature or literary analysis that engages with the issue of university fossil fuel divestment.” (Students could also opt out of the zine and write a more conventional final essay). Here are some excerpts from an email that I sent to the class elaborating on this non-traditional assignment. There\u27s a quotation by W.B. Yeats that strikes me as relevant here: Out of the quarrel with others we make rhetoric; out of the quarrel with ourselves we make poetry. What I understand Yeats to mean is that honest creative writing explores its subject, rather than argues a pre-established position. (For his word poetry in that quotation, you could equally substitute drama, or fiction, creative nonfiction, etc.) Our goal is to write literature, not propaganda . . . . While the work you create should shed light on some aspect of the divestment issue, it needn\u27t do so directly. In fact, it’s possible to shed light on the issue without even mentioning the word “divestment.” Consider, for example, the first novel we read this semester, Margaret Atwood’s Oryx and Crake. That novel engages with a host of environmental topics, among them global climate change, genetic engineering, population growth, the treatment of animals, and environmental justice. It doesn\u27t tell the reader what to do or think about any of these issues; rather, it explores them imaginatively, but it does so in a way that I believe encourages readers to be more reflective about each of those issues than they were before starting the novel. It sheds light on these issues. [K]eep in mind that this assignment does not expect that you will take a particular position. It does not assume that you will create a work of literature or literary criticism that is “for” fossil fuel divestment. (I\u27m not even sure that a work of art can ever be “for” or “against” a particular action. Is Oryx and Crake for or against the human manipulation of the environment? Who knows?—it\u27s a work of imaginative writing that tells a story. Readers can engage their own sense of values based upon the encounter with the imaginative work). I hope that this advice is helpful and that you feel authorized to write freely. I created the opportunity for the assignment because I believe that your voice—both individually and collectively—does matter and I wanted to facilitate a way for it to be heard, in however modest a fashion. What that voice says is entirely up to you. Those twenty voices from the class combine to form the collective voice you encounter here in the Sound Ideas archive On Divestment. On behalf of the writers and critics in ENGL 374, I invite you explore these remarkable poems, short stories, essays, and plays in their entirety. Best wishes, Prof. William Kupinse Department of Englis