Thursday Extra October 1st

Peter-Michael Osera and Charlie Curtsinger will discuss graduate programs in computer science.

October 1st
4:15 p.m.
Noyce 3821

Snacks will be available in the CS Commons at 4:00 p.m.

CS Table for 9/29: Youtube, ContentID, and Fair Use

This week we'll be talking about Youtube and its efforts to enforce the rights of copyright holders with its ContentID system. In particular, we'll talk about the the history of ContentID and its effects on content creators and copyright holders over the last couple of years. Computer science table (CS Table) is a weekly meeting of Grinnell College community members (students, faculty, staff, etc.) interested in discussing topics related to computing and computer science. CS Table meets Tuesdays from 12:00-12:45 in JRC 224C. Contact the CS faculty for the weekly reading. Students on meal plans, faculty, and staff are expected to cover the cost of their meals. Visitors to the College and students not on meal plans can charge their meals to the department. For the up-to-date CS Table schedule, please visit the CS Table webpage.

Double Feature CS Talks on September 23 & 24

On Wednesday, September 23, Dr. Ursula Wolz gives a talk on two of her research projects: "Does Learning Computer Science Require a Teacher? Reflections on Automated Tutors and Learning Communities."

On Thursday, September 24, our own Samuel Rebelsky gives a short talk: "Scripting GIMP with Racket."

Both talks are in Science-3821 at 4:15 PM, preceded by refreshment in the CS Commons at 4:00.

Ursula Wolz will be teaching at Grinnell as a Noyce Visiting Professor in Spring 2016. Dr. Wolz is currently involved in two projects, one to create a very robust mechanical tutor using a sophisticated rule base, the other to create face-to-face communities of coders that remove, or at least reduce, the technology divide. She will provide a quick overview of both projects, and then invite stimulating discussion of the major technological and ethical issues involved.

Professor Rebelsky's talk is practice for an upcoming presentation at RacketCon in St. Louis. The GNU Image Manipulation Program, or GIMP, is an open-source alternative to Photoshop. In the early days of GIMP, the designers added a scripting language, Script-Fu, based on Scheme. Over the years, Script-Fu has been superseded by Python-Fu, although Script-Fu remains an option, albeit with a primitive IDE. Over the past few years, my students and I have built a library that allows programmers to script GIMP using Racket and the DrRacket IDE. In addition to providing the “glue” between GIMP and Racket, we also added a library of routines more amenable to novice programmers. In this talk, we will discuss the design of both the “glue” and the broader library. We will also discuss a related introductory course in CS that uses multiple models of image making as the motivating problem domain.

CS Table for Tuesday, September 15: "Automated Cars and Cybersecurity"

Our topic at this week's Computer Science Table will be software vulnerabilities in cars, as described in this article:

Gallagher, Sean. Highway to Hack: Why We're Just at the Beginning of the Auto-Hacking Era. Ars Technica, August 13, 2015.
http://arstechnica.com/security/2015/08/highway-to-hack-why-were-just-at-the-beginning-of-the-auto-hacking-era/

Computer Science table (CS Table) is a weekly meeting of Grinnell College community members (students, faculty, staff, etc.) interested in discussing topics related to computing and computer science. CS Table meets Tuesdays from 12:00 to 12:45 in Rosenfield 224C. Contact the CS faculty for the weekly reading. Students on meal plans, faculty, and staff are expected to cover the cost of their meals. Visitors to the College and students not on meal plans can charge their meals to the department.

Thursday Extra: GNU/Linux System Administration Projects

On Thursday, September 10, Reilly Noonan Grant 2018, Alex French 2017, Bazil Mupisiri 2018, and Logan Goldberg 2018 will present their summer 2015 work on projects for the maintenance and improvement of MathLAN:

We shall describe the various projects completed to improve the computer science department’s MathLAN systems over the summer and give an overview of the field of system administration. MathLAN’s operating system is GNU/Linux, a free software, which gives the user more control over the computer. This made the course very open-ended. As such, the projects completed are varied and relate to many different aspects of system administration. The more noticeable effects of these projects are an improvement in the MathLAN login screen, and a revision of the CS website, yet to be implemented.

At 4:00 p.m., refreshments will be served in the Computer Science Commons. The talk, “GNU/Linux System Administration Projects,” will begin at 4:15 p.m. in Noyce 3821. Everyone is welcome to attend!

CS Table, September 1, 2015: "Google and Elections"

This week at CS Table, we will consider a recent article on the potential power of Google to swing elections:

Rogers, Adam (2015). “Google's Search Algorithm Could Steal the Presidency.” Available on line at http://www.wired.com/2015/08/googles-search-algorithm-steal-presidency.

IMAGINE AN ELECTION -- A close one. You're undecided. So you type the name of one of the candidates into your search engine of choice. (Actually, let's not be coy here. In most of the world, one search engine dominates; in Europe and North America, it's Google.) And Google coughs up, in fractions of a second, articles and facts about that candidate. Great! Now you are an informed voter, right? But a study published this week says that the order of those results, the ranking of positive or negative stories on the screen, can have an enormous influence on the way you vote. And if the election is close enough, the effect could be profound enough to change the outcome.

In other words: Google's ranking algorithm for search results could accidentally steal the presidency. “We estimate, based on win margins in national elections around the world,” says Robert Epstein, a psychologist at the American Institute for Behavioral Research and Technology and one of the study's authors, “that Google could determine the outcome of upwards of 25 percent of all national elections.”

Those of you who want to delve more deeply into the issue can read (or skim) the full journal article:

Epstein, Robert, and Robertson, Ronald E. (2015). “The Search Engine Manipulation Effect (SEME) and Its Possible Impact on the Outcomes of Elections.” Proceedings of the National Academy of Sciences, 112 (33). Available on line at http://www.pnas.org/content/112/33/E4512.abstract.

Internet search rankings have a significant impact on consumer choices, mainly because users trust and choose higher-ranked results more than lower-ranked results. Given the apparent power of search rankings, we asked whether they could be manipulated to alter the preferences of undecided voters in democratic elections. Here we report the results of five relevant double-blind, randomized controlled experiments, using a total of 4,556 undecided voters representing diverse demographic characteristics of the voting populations of the United States and India. The fifth experiment is especially notable in that it was conducted with eligible voters throughout India in the midst of India’s 2014 Lok Sabha elections just before the final votes were cast. The results of these experiments demonstrate that (i) biased search rankings can shift the voting preferences of undecided voters by 20% or more, (ii) the shift can be much higher in some demographic groups, and (iii) search ranking bias can be masked so that people show no awareness of the manipulation. We call this type of influence, which might be applicable to a variety of attitudes and beliefs, the search engine manipulation effect. Given that many elections are won by small margins, our results suggest that a search engine company has the power to influence the results of a substantial number of elections with impunity. The impact of such manipulations would be especially large in countries dominated by a single search engine company.

Computer Science Table is a weekly meeting of Grinnell College community members (students, faculty, staff, etc.) interested in discussing topics related to computing and computer science. CS Table meets Tuesdays from 12:00-12:45 in JRC 224C. Contact the CS faculty for the weekly reading. Students on meal plans, faculty, and staff are expected to cover the cost of their meals. Visitors to the College and students not on meal plans can charge their meals to the department.

Congratulations to our graduates!

The Computer Science majors of the class of 2015 are:

  • Hannah Jun Cohn
  • Nathalie Simasing Ford
  • Lee Walker Gatchell
  • Alexis Lauren Greenwell
  • Chenheli Hua
  • Spencer Bernard Liberto
  • Anqing Liu (with honors)
  • Lea Marolt Sonnenschein (with honors)
  • Ethan Ratliff-Crain
  • Daniel Maximino Torres
  • Patrick Nelson Triest
  • June Oriana Yolcuepa
  • Lifeng Yuan

Congratulations to all!

Thursday Extra: "Beyond the PDP-11"

On Thursday, April 30, Brooks Davis (Senior Software Engineer, SRI International) will describe a proposed processor architecture to support memory-safe programming:

The C programming language (combined with C++) is used to implement all important modern operating systems and the runtimes of most higher level programming languages. Despite the ease of implementing serious security bugs in C, billions of lines of software is written in it and our daily lives depend on much of that software. It is surprising that all popular CPU architectures provide memory safety mechanisms substantially identical to those on the PDP-11 on which C was written in 1972! Our research aims to change that.

In this talk I provide an introduction to the conventional memory model of C and cover some of the problems this model causes. I will then discuss our solution, the CHERI CPU and our modified C compiler and how we took it from an early prototype to something that can bring memory safety to virtually all C code without code changes.

At 4:15 p.m., refreshments will be served in the Computer Science Commons. The talk, “Beyond the PDP-11: Architectural support for a memory-safe C abstract machine,” will begin at 4:30 p.m. in Noyce 3821. Everyone is welcome to attend!

Thursday Extra: "Enhancing Myro Java using Android"

On Thursday, April 17, Nora Bresette Buccino will discuss the development of an application programming interface for small robots in Java, with extensions to the Android environment:

The use of personal robots in computing is becoming more ubiquitous as robots are a good way to attract students and introduce them to the subject of computer science. Therefore, it is important to make use of all the features of the robots to give users a sense of the capabilities provided by robotics. The API (Application Programming Interface) defined by the Institute for Personal Robots in Education, called Myro, originally created in Python, has now been adapted to many other popular programming languages including Java. The Myro Java API created for the Scribbler robots by Professor Douglas Harms of DePauw University included most of the features of Myro Python. Our goals in this project were to add features to the Myro Java API, to enhance the user's capabilities, and to attempt to incorporate Android development into Myro Java.

Smart phones and tablets have become an integral part of the way we communicate and learn. Not only can these devices be used to communicate with other people, but they can also communicate with other devices through Bluetooth and infrared sensors. Thus these types of devices can interact with devices such as robots and applications can be created to control these robots. Therefore, we decided to integrate Myro and Android to provide the opportunity to not only learn about robotics but to also learn about Android programming and mobile application development.

At 4:15 p.m., refreshments will be served in the Computer Science Commons. The talk, “Enhancing Myro Java using Android,” will begin at 4:30 p.m. in Noyce 3821. Everyone is welcome to attend!

Thursday Extra: "A Refined C-based Infrastructure and Curriculum to Support Robots in Introductory CS"

On Thursday, April 2, 2015, Professor Walker and his student development team will discuss on-going work on the infrastructure and curriculum for CSC 161.

Context: On Friday, April 10, students, Vasilisa Bashlovkina, Anita DeWitt, Nicholas Knoebber, and Anqing (Jason) Liu — with Professor Walker, will be presenting a talk to the Central Plains Regional Conference of the Consortium for Computer Science in Colleges. This presentation will serve as a preliminary offering of that talk.

Abstract: Since 2011, a student-faculty team at Grinnell College has developed and refined a complete course package, called MyroC, comprising a C-based infrastructure, course materials, laboratory exercises, problem sets, projects, etc. for introductory computer science. Using a lab-based pedagogy, the course emphasizes imperative problem solving and utilizes the control of robots as an integrative application theme. Although this approach has had much success, on-going technical challenges have included the lack of portability, unintuitive image processing, and forced sequential processing of robot commands. This paper describes improvements to both the C library and course materials (e.g., examples, laboratory exercises, and projects) that enhance student learning through laboratory experiences. Refinements have focused upon transforming the infrastructure from an extensive, largely non-portable C++ package to a simple C environment, allowing users to work with images directly as 2D arrays of pixels, non-blocking alternatives for many robot-motion commands, and concurrent control for the movement of multiple robots. The paper also describes assessment of effectiveness, including student reactions and enrollment statistics. Finally, this paper demonstrates the effectiveness of student-faculty collaboration in course development.

Scheduling Details: Refreshments will be served at 4:15 p.m. in the Computer Science Commons (Science 3817), and the talk will begin at 4:30. Everyone is welcome to attend!

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