This study investigated the role of self-directed learning (SDL) in problem-based learning (PBL) and examined how SDL relates to self-regulated learning (SRL). First, it is explained how SDL is implemented in PBL environments. Similarities between SDL and SRL are highlighted. However, both concepts differ on important aspects. SDL includes an additional premise of giving students a broader role...

In real-time systems, the capability to achieve short or even predictable reaction times is essential. In this paper, we take a pragmatic approach by proposing priority-based scheduling in SDL combined with a mechanism to suspend and resume SDL agents. More specifically, we define adequate syntactical extensions of SDL and show that they are compliant with the formal SDL semantics. We have impl...

An SDL pattern is a reusable software artifact representing a generic solution for a recurring design problem. It is required that SDL be the applied design language. However, just offering an SDL pattern pool to the system designer will not result in the expected benefits of software reuse, such as shorter development cycles, improved quality, or easier maintenance of the resulting products. A...

This paper presents a new approach to the formal veriication of SDL speciications. SDL is given de-notational semantics based on the concepts of streams and stream processing functions in the formal framework of Focus. The formalization of SDL revealed some aspects of SDL which are handled un-precisely in the Z.100, e.g., the concept of time, and gives a solution to them. The formal semantics i...

In November 1999, the current version of specification and description language (SDL), commonly referred to as SDL-2000, passed through ITU-T. In November 2000, the formal semantics of SDL2000 was officially approved to become part of the SDL language definition. It covers both the static and the dynamic semantics, and is based on the formalism of abstract state machines (ASMs). To support exec...

In this paper, we present an efficient way how protocols modelled in SDL (Specification and Description Language) can be transformed into efficient implementations for resource-constrained wireless sensor nodes. We will show how SDL concepts such as processes, timers, or signals can be mapped to operating system concepts provided by the Reflex operating system. Our approach is based on optimize...

1 SDL is the premier language for specification, design and development of real time systems, and in particular for telecommunication applications. SDL-2000 became the international standard in force in November 1999, replacing the previous version. This paper gives an overview of SDL-2000 and fills the gap between previously published tutorials and the current SDL standard.

This paper presents a new approach to the formal veri cation of SDL speci cations SDL is given de notational semantics based on the concepts of streams and stream processing functions in the formal framework of Focus The formalization of SDL revealed some aspects of SDL which are handled un precisely in the Z e g the concept of time and gives a solution to them The formal semantics is the start...