John T. Korb

Computational Thinking in Elementary and Secondary Teacher Education

Computational thinking (CT) is broadly defined as the mental activity for abstracting problems and formulating solutions that can be automated. In an increasingly information-based society, CT is becoming an essential skill for everyone. To ensure that students develop this ability at the K-12 level, it is important to provide teachers with an adequate knowledge about CT and how to incorporate it into their teaching. This article describes a study on designing and introducing computational thinking modules and assessing their impact on preservice teachers’ understanding of CT concepts, as well as their attitude towards computing. Results demonstrate that introducing computational thinking into education courses can effectively influence preservice teachers’ understanding of CT concepts.

Binding software to specific native hardware in a VM environment: the puf challenge and opportunity

There are many practical situations in which, by policy, software is supposed to run on a specific hardware instance. This is not only useful to combat piracy, but also in national security situations, such as a battlefield loss of critical technology, where it is paramount that an enemy be unable to rehost the system on a different set of (possibly counterfeit) hardware. To achieve this binding, software vendors use techniques that can easily be foiled through virtualization: Whatever the software expected from the legitimate hardware, can instead be provided by a virtualization layer to fool the software into believing it is running on legitimate hardware. The recently demonstrated feasibility of physically unclonable functions (PUFs) make this attack somewhat harder, in that it is no longer possible to simulate the presence of the hardware in software. If PUF technology is used, carrying out this attack would require modification of the internals of the software to be fooled, a harder task but still possible with moderate effort. We present a way of using PUFs in a manner that makes it significantly harder for the attacker to carry out the attack. We also review the challenges and opportunities for virtualization that PUFs bring.

CSNET protocol software: the IP-to-X.25 interface

CSNET is built on the Department of Defense network (ARPANET), public packet-switched physical networks (Telenet), and a telephone-based relay network (Phonenet). Some CSNET sites have direct connections to ARPANET, some have direct connections to Telenet, and some have connections only to telephone-based relay machines. The chief objective of CSNET is to provide a network interconnection for all groups engaged in Computer Science Research. CSNET has adopted TCP/IP as its standard transport level protocols. The Transmission Control Protocol (TCP) [POST81] is an end-to-end protocol. It establishes communications between two processes that are running on different machines, detects and corrects errors, controls data flow, and provides reliable communications. Application programs call TCP to transfer data across the network. TCP, in turn, uses the Internet Protocol (IP) [POST81] to send data to the appropriate network. CSNET communications such as file transfer, remote login, and process-to-process communication over the network assume that a TCP interface is available at CSNET sites. Since ARPANET sites are required to support the TCP/IP protocols, CSNET sites connected directly to the ARPANET automatically have access to TCP/IP. Phonenet relays connect directly to the ARPANET; they too have access to TCP to relay mail onto the ARPANET. Telenet does not use the TCP/IP protocols. Consequently, CSNET sites that are connected only to Telenet need additional software before they can communicate on CSNET. That software is described in this paper -- it provides an interface between the public packet - switched protocol X.25 [CCITT78] and TCP/IP. Although the design outlined here is applicable to any vendors system, our implemention is for a Digital Equipment Corporation VAX running the Western Electric UNIX [UNIX78] operating system as modified by the University of California at Berkeley. This report focuses on the technical issues involved in building software to interface TCP/IP and X.25. The tariff structure for public networks is discussed only to the extent that it influences our design. Other issues such as access control, and protocol selection are beyond the scope of this report.

Learning to teach computer science: the need for a methods course

A multipronged approach to preparing computer science teachers is critical to success.

Command execution in a heterogeneous environment

As a users computing environment grows from a single time-shared host to a network of specialized and general-purpose machines, the capability for the user to access all of these resources in a consistent and transparent manner becomes desirable. Instead of viewing commands as binary files, we expect the user to view commands as services provided by servers in the network. The user interacts with a personal workstation that locates and executes services on his behalf. Executing a single service provided by any server in the network is useful, but the user would also like to combine services from different machines to perform complex computations. To provide this facility we expand on the UNIX notion of pipes to a generalized pipeline mechanism containing services from a variety of servers. In this paper we explain the merits of a multi-machine pipeline for solving problems of accessing services in a heterogeneous environment. We also give a design and performance evaluation of a general mechanism for multi-machine pipes using the DARPA UDP and TCP protocols.

Challenges and opportunities in conducting educational research in the computer science classroom: how to collect empirical evidence to assess whether students really learned (abstract only)

This workshop will provide CS educators with tools to conduct educational research. Primary objectives of this workshop are: (1) learn basic principles of educational research; (2) learn about educational research designs: qualitative vs. quantitative; experimental vs. quasi-experimental; case studies, survey; and (3) to practice designing research. This workshop will help participants make informed decisions when faced with limitations of educational research and collect empirical evidence about what works in the classroom. In addition, we will also discuss how to develop robust student outcome measures, such as surveys and tests.