Roland Hübscher

Tools for Scaffolding Students in a Complex Learning Environment: What Have We Gained and What Have We Missed?

This article discusses the change in the notion of scaffolding from a description of the interactions between a tutor and a student to the design of tools to support student learning in project-based and design-based classrooms. The notion of scaffolding is now increasingly being used to describe various forms of support provided by software tools, curricula, and other resources designed to help students learn successfully in a classroom. However, some of the critical elements of scaffolding are missing in the current use of the scaffolding construct. Although new curricula and software tools now described as scaffolds have provided us with novel techniques to support student learning, the important theoretical features of scaffolding such as ongoing diagnosis, calibrated support, and fading are being neglected. This article discusses how to implement these critical features of scaffolding in tools, resources, and curricula. It is suggested that if tools are designed based on the multiple levels of the student understanding found in a classroom, tools themselves might be removed to achieve fading.

Computer support for learning through complex problem solving

T ypical back-of-the-chapter problems don’t provide students with the context to make the problems motivating and to facilitate transfer (use of the knowledge in other situations). Authentic problems— problems that are real, that might arise in the student’s life, or that are known to the student—have enormous potential for learning. Authentic problems typically require a wide range of knowledge and skills for successful solution, and they encourage transfer by demonstrating when the knowledge is useful. However, authentic problems tend to be complex—students need two kinds of help to make them work for learning:

Applying tabu search with influential diversification to multiprocessor scheduling

Abstract We describe a tabu search approach to the scheduling problem of minimizing the makespan on n tasks on m equivalent processors. This problem is isomorphic to a variant of the multiple bin packing problem. We make use of a candidate list strategy that generates only a small subset of all possible moves, and employ a dynamic tabu list for handing tabu restrictions. We also introduce an influential diversification component to overcome an entrenched regionality phenomenon that represents a “higher order” difficulty encountered by local search methods. Influential diversification notably improves the behavior and quality of the solutions of our tabu search procedure as the search horizon grows. Results are presented for a range of problems of varying dimensions, and our method is also compared to an extended simulated annealing approach that previously has produced the best solutions for the isomorphic bin packing problem.

Intra-group and intergroup: an exploration of learning with complementary collaboration tools

In this paper, we explore the learning that occurred in two types of collaborative learning environments in a seventh grade life sciences classroom: an intragroup environment and an intergroup environment. Students used both types of collaboration tools, each tuned to the needs of the task they were doing within or across groups. We found that the learning outcomes in the two collaborative settings were different. During the intragroup collaboration, students focused more on the structure and behavior of the designs. The inter-group environment on the other hand, led them to discuss the function/s of their models, ask for and provide justifications for the functions. We discuss the results and suggest integration of the inter and intra group tools.

Visual language theory: towards a human computer interaction perspective

The main reason for using visual languages is that they are often far more convenient to the user than traditional textual languages. Therefore, visual languages intended for use by both computers and humans ought to be designed and analyzed not only from the perspective of computational resource requirements, but also from the perspective of languages that are cognitively usable and useful. Theoretical and practical research on visual languages needs to take into account the full context of a coupled human-computer system in which the visual language facilitates interactions between the computational and the cognitive parts. This implies that theoretical analyses ought to address issues of comprehension, reasoning, and interaction in the cognitive realm as well as issues of visual program parsing, execution, and feedback in the computational realm. The human aspect is crucial to visual languages, and therefore we advocate a correspondingly broadened scope of inquiry for visual language research. In this chapter we describe aspects of human use of visual languages that ought to be important considerations in visual language research and design, and summarize research from related fields such as software visualization and diagrammatic reasoning that addresses these issues. A framework consistent with the broadened scope of visual language research is proposed and used to categorize and discuss several formalizations and implemented systems. In the course of showing how a sample of current work fits into this framework, open issues and fruitful directions for future research are also identified.

Logically Optimal Curriculum Sequences for Adaptive Hypermedia Systems

Curriculum sequencing is an important technique used in many adaptive hypermedia systems. When following one of the possible page sequences, visiting some pages may become redundant, because its content has been covered already by another page. Using disjunctive and conjunctive prerequisites instead of partial orders to describe the many possible sequences, logical redundancy between pages can be computed on the fly without burdening the teaching model with that task [1]. Although the general case of finding all redundant pages is NP-Complete [2] and thus, intractable unless P = NP, a large subset can be located efficiently in realtime. The advantage of separating out logical redundancy, the advantage of using conjunctive and disjunctive prerequisites, and the algorithms to find redundant pages are discussed. An interesting characteristic of the presented approach is that it can be used together with a wide variety of user and teaching models.

Adaptive Navigation for Learners in Hypermedia Is Scaffolded Navigation

Adaptive navigation support can be of great help in large hypermedia systems supporting learners as well as users searching for specific information. A wide variety of adaptive mechanisms have been implemented in existing adaptive hypermedia systems that provide better and better suggestions to the user what hyperlinks to follow. We suggest that adaptive navigation support should scaffold a learner in an educational hypermedia system to select the appropriate links. We show that this implies that selecting a link is an educationally relevant activity that should not always be reduced to a trivial task by powerful adaptive mechanisms. It follows that learners require sometimes different kinds of adaptive navigation support than users looking for information. Finally, we will suggest how to extend current mechanisms to provide scaffolded navigation support to learners.

Visual Constraint Rules

Abstract Visual rule-based languages have been used quite successfully to program graphical simulations. They all use rewrite rules, which have the often-mentioned advantage that a program can supposedly be extended simply by adding a few more rules. In practice, however, the rules tend to depend on each other, and instead of just adding rules, existing rules need to be changed. Visual constraint rules combine ideas from rule-based programming and constraint programming to create declarative forward-chaining-like rules that can be used in a more modular way to support iterative programming. Libraries of visual descriptions can be built and reused to compose complex behavior, which makes exploring the space of possible descriptions of simulations easier. This is valuable for the intended educational use of Cartoonist, a visual programming environment to build simulations. Furthermore, constraint rules also provide a way to describe a variety of parallel behaviors that are important in simulations, yet are not supported by similar systems.

Modeling learners as individuals and as groups

Adaptive navigation support normally attempts to make selecting a relevant hyperlink as easy as possible. However, in educational applications, this may have negative learning effects since selecting a link is sometimes an important educational problem for the student to solve. To provide appropriate scaffolding to students, it is necessary to understand how they navigate in hypermedia sites. By grouping students with similar conceptual (mis)understanding we were able to uncover a small set of characteristic navigation patterns, and to demonstrate that students with similar conceptual understanding have similar navigation patterns.

Composing complex behavior from simple visual descriptions

An often-mentioned advantage of rule-based programming languages is that a program can be extended simply by adding a few more rules. In practice however the rules tend to be dependent on each other and instead of just adding rules, existing rules need to be changed. The unique rules in Cartoonist, a rule-based visual programming environment to build simulations, provides a solution to this problem. Cartoonists rules can be used in a more modular way supporting an iterative mode of programming. Libraries of visual descriptions can be built and reused to compose complex behavior from these descriptions. This makes exploring the space of possible descriptions of simulations easier, which is valuable for intended educational use of Cartoonist. Another advantage of Cartoonist is that its programs tend to have fewer and simpler rules than programs written for comparable systems.An often mentioned advantage of rule based pro gramming languages is that a program can be ex tended simply by adding a few more rules In prac tice however the rules tend to be dependent on each other and instead of just adding rules existing rules need to be changed The unique rules in Cartoon ist a rule based visual programming environment to build simulations provides a solution to this prob lem Cartoonist s rules can be used in a more mod ular way supporting an iterative mode of program ming Libraries of visual descriptions can be built and reused to compose complex behavior from these descriptions This makes exploring the space of pos sible descriptions of simulations easier which is valu able for intended educational use of Cartoonist An other advantage of Cartoonist is that its programs tend to have fewer and simpler rules than programs written for comparable systems