Importing design patterns from software engineering to the computer science education (CSE) field was followed by defining patterns and pattern languages suitable for CS courses. The main goal of incorporating patterns in CSE was to enhance students' programming abilities, as well as their design and problem-solving skills. Accordingly, various instructional materials were suggested for using patterns in classroom learning activities, such as collections of patterns and related programming assignments. However, the existing pattern-based materials seem to be insufficient for implementation in the classroom, especially when teaching introductory courses that emphasize syntax and programming language features. Therefore, alternative methods using applicative models for pattern-based instruction, which emphasize problem solving and program design issues rather than specific language features and syntax, should be developed and assimilated within the CS teaching community. We believe that successful implementation of such models should be accompanied by appropriate teachertraining.In this paper we describe an initial effort to expose CS teachers to the notions of pedagogical patterns and pattern-based instruction, aimed at motivating them to meaningfully adopt and adapt patterns to their concrete pedagogical needs.

Novices often experience difficulties in problem analysis and solution construction. Pattern-oriented instruction (POI) is a pedagogical approach based on incorporating patterns into instruction design. It is well-grounded in cognitive theories concerning knowledge construction and organization as well as the acquisition of expertise in problem solving. We show that the incorporation of algorithmic patterns through POI may enhance the construction of algorithmic problem-solving knowledge. Findings of a comparative research study showed that novices who studied according to the POI approach exhibited better problem-solving competence than those who studied in a traditional manner. Specifically, they were more competent in problem decomposition and solution construction.

A special program for high school has been in operation in Israel whose aim is to expose young students to the field of computing. During their studies the students are required to develop a software project, and thus gain experience in software design. In the past students lacked proper guidance in technologically demanding projects. Here we describe how the work of a student who chose to develop an engine for automatic completion of sentences by the computer was enhanced through cooperation with academia in the innovative "Computer Science, Academia and Industry" educational program. Albeit highly talented, the student lacked necessary formal knowledge in advanced computing technologies. A graduate student who specializes in the field has mentored the high school student throughout design and implementation phase, enabling him to grasp an intuitive understanding of state of the art algorithms, and contribute creative ideas of his own, resulting in an award-winning project of scientific significance.

Recursion is a central concept in computer science, yet it is a very difficult concept for beginners to learn. In this paper we focus on a specific aspect of comprehending recursion -the conception of the base case as an integral component of a recursive algorithm. We found that students have difficulties in identifying base cases: they handle redundant base cases; ignore boundary values and degenerated cases; avoid out-of-range values; and may even not define any base cases when formulating recursive algorithms. We also found that students have difficulties in evaluating recursive algorithms that deal with imperceptible base cases. We suggest that teachers should make a special effort to discuss different aspects of the base case concept. Emphasis should be put on both declarative and procedural aspects of categorizing and handling base cases as part of recursion formulation.