74,580 research outputs found
Report on a User Test and Extension of a Type Debugger for Novice Programmers
A type debugger interactively detects the expressions that cause type errors.
It asks users whether they intend the types of identifiers to be those that the
compiler inferred. However, it seems that novice programmers often get in
trouble when they think about how to fix type errors by reading the messages
given by the type debugger. In this paper, we analyze the user tests of a type
debugger and report problems of the current type debugger. We then extend the
type debugger to address these problems. Specifically, we introduce
expression-specific error messages and language levels. Finally, we show type
errors that we think are difficult to explain to novice programmers. The
subjects of the user tests were 40 novice students belonging to the department
of information science at Ochanomizu University.Comment: In Proceedings TFPIE 2014, arXiv:1412.473
Oii-web: An interactive online programming contest training system
In this paper we report our experience, related to the online training for the
Italian and International Olympiads in Informatics. We developed an interactive online
system, based on CMS, the grading system used in several major programming contests
including the International Olympiads in Informatics (IOI), and used it in three distinct
context: training students for the Italian Olympiads in Informatics (OII), training teachers
in order to be able to assist students for the OII, and training the Italian team for the
IOI. The system, that is freely available, proved to be a game changer for the whole italian
olympiads in informatics ecosystem: in one year, we almost doubled the participation to
OII, from 13k to 21k secondary school students.
The system is developed basing on the Contest Management System (CMS, http://cms-
dev.github.io/), so it is highly available to extensions supporting, for instance, the pro-
duction of feedback on problems solutions submitted by trainees. The system is also freely
available, with the idea of allowing for support to alternative necessities and developmen
Abstract State Machines 1988-1998: Commented ASM Bibliography
An annotated bibliography of papers which deal with or use Abstract State
Machines (ASMs), as of January 1998.Comment: Also maintained as a BibTeX file at http://www.eecs.umich.edu/gasm
CAPTCHaStar! A novel CAPTCHA based on interactive shape discovery
Over the last years, most websites on which users can register (e.g., email
providers and social networks) adopted CAPTCHAs (Completely Automated Public
Turing test to tell Computers and Humans Apart) as a countermeasure against
automated attacks. The battle of wits between designers and attackers of
CAPTCHAs led to current ones being annoying and hard to solve for users, while
still being vulnerable to automated attacks.
In this paper, we propose CAPTCHaStar, a new image-based CAPTCHA that relies
on user interaction. This novel CAPTCHA leverages the innate human ability to
recognize shapes in a confused environment. We assess the effectiveness of our
proposal for the two key aspects for CAPTCHAs, i.e., usability, and resiliency
to automated attacks. In particular, we evaluated the usability, carrying out a
thorough user study, and we tested the resiliency of our proposal against
several types of automated attacks: traditional ones; designed ad-hoc for our
proposal; and based on machine learning. Compared to the state of the art, our
proposal is more user friendly (e.g., only some 35% of the users prefer current
solutions, such as text-based CAPTCHAs) and more resilient to automated
attacks.Comment: 15 page
The KB paradigm and its application to interactive configuration
The knowledge base paradigm aims to express domain knowledge in a rich formal
language, and to use this domain knowledge as a knowledge base to solve various
problems and tasks that arise in the domain by applying multiple forms of
inference. As such, the paradigm applies a strict separation of concerns
between information and problem solving. In this paper, we analyze the
principles and feasibility of the knowledge base paradigm in the context of an
important class of applications: interactive configuration problems. In
interactive configuration problems, a configuration of interrelated objects
under constraints is searched, where the system assists the user in reaching an
intended configuration. It is widely recognized in industry that good software
solutions for these problems are very difficult to develop. We investigate such
problems from the perspective of the KB paradigm. We show that multiple
functionalities in this domain can be achieved by applying different forms of
logical inferences on a formal specification of the configuration domain. We
report on a proof of concept of this approach in a real-life application with a
banking company. To appear in Theory and Practice of Logic Programming (TPLP).Comment: To appear in Theory and Practice of Logic Programming (TPLP
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