Declarative and procedural

The general grammars and the mixture of declarative and procedural Prolog code allows easy grammar rule writing for other reactions. As an additional example, consider heterocyclic rings. The grammar rule... 

Module is used as a repository of declarations and procedures to design advanced Access applications. 

In the previous section, we discussed the structure of a conceptual model that can be used to represent a design methodology. But the value of this model rests with the effectiveness of the representation schemes that one employs to describe the declarative and procedural components of the model in a way that the computer can understand. Thus, we are led to the need of defining a design-oriented language for the description of the computational process. 

What appears to be missing in both Squire s and Anderson s memory dichotomy is an explanation of how the two types of memories work together. I suggest that both declarative and procedural knowledge are required in any activation of a schema. 

The distinction of declarative and procedural representations is directly related to the classification of the models from the point of view of an external solver [303], Open-form model representations provide interfaces to access the full equation system of the model, for example, in form of a CAPE-OPEN equation set object [894], Alternatively, the closed-form model representation provides interfaces which only enable to set inputs and to retrieve outputs of the model. Typically, declarative representations require an external solver and use an open-form interface, whereas procedural representations come with an integrated solver and usually have an interface of the closed-form type. 

Knowledge machine (KM) is a frame-based knowledge representation langnage similar to KRL and other KL-ONE representation languages such as Loom and CLASSIC [13-15], In KM, a frame denotes either a class (i.e., type) or an instance (i.e., individual). Frames have slots, or binary predicates, in which the fillers are axioms about the slot s value. These axioms have both declarative and procedural semantics, allowing for procedural inference. 

ACT-R is composed of perceptual-motor and memory modules implemented as production rules. Both declarative and procedural memory are modeled. A pattern-matching mechanism is used to select production rules applicable to the situation. Buffers are used to interact with and represent the state of modules. ACT-R is implemented as a computer language. Users create a program containing relevant task data to model the task and task performance. An extension of ACT called SNIF-ACT that incorporates a Bayesian navigation mechanism was described earlier in this chapter (Fu and Pirolli 2007). 

The first type of information is rather technical. On-line technical information is offered in response to questions of the authors. When, for example, the author wants to know how to explain a concept, the coach should be able to answer. The author, however, is not an instructional design specialist, he not only lacks declarative and procedural knowledge but also conditional knowledge about when and why the use of instructional methods and strategies can be useful. He makes errors, shows misconceptions and lacks instmctional decision-making skills. Therefore, this second type of information should also be delivered to the author and implemented in the coach. 

In order to be able to construct such program the first activity is to construct the information basis of the Hypermedia Tutorial. This is not only the declarative and procedural knowledge about the subject but also, in the special case of Hypermedia information, about the recognized necessary pre-requisites (which will allow students who don t possess them to get them) and also complementary information capable of satisfying the curiosity of the learner (and making the program attractive). In order to define this information as well as the way it is presented and how to control the process (exercises, games,...) one first attempt must be done based on the experience and intuition of the educationalists. 

The distinction between declarative and procedural knowledge has been abandoned by researchers in Artificial Intelligence as not fruitful for their enterprise. The problem with the distinction from their point of view is that any expression becomes executable, hence procedural, if one programs an interpreter for it conversely, the code for any procedure can be treated as data by other procedures, and hence function declaratively. But these observations ate not directly relevant to cognitive psychology. The question whether the human mind has the procedural-declarative distinction embedded in it or not is an empirical question that cannot be settled by reference to the properties of programming languages. 

Common items that are found in packages include type and subtype declarations, functions and components. Types and subtypes that are implicitly accessible to any design are declared in the STANDARD package. This package cannot be modified by the user and is stored in die STD library along with another, TEXTIO. However, the type declarations and procedures that this contains cannot be used if a design is to be synthesized. 

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