Coupling concepts for simulation:A systematic and comprehensive view and advantages with declarative models

A brief review of the importance of simulation-based engineering and science(including social sciences)is followed by a historic perspective of model-based simulation.Section 2 is on declarative modeling of component systems as well as its advantages for self-documentation and for computer-aided checks and coupling.As an example for declarative modeling,General System Theory(GEST)implementor is given.In Sec.3,basic concepts for coupling of component models,and rules for computer-assisted coupling specification are explained.Section 4 is devoted to possible computerized checks in couplings of declarative models such as:(1)automatic unit checking to avoid meaning-less input/output matching at the time of coupling specification,(2)automatic threshold checking to provide warnings and/or to avoid disasters,and(3)automatic unit conversion for convenience of using library models.Section 5 is about several layers of nested couplings for modeling systems of systems.In Sec.6,two types of variable couplings are discussed:(1)couplings with variable connections(to allow input/output relations of models to depend on time or state conditions)and(2)coupling with variable component models(to allow component(or coupled)models to be switched based on time or state conditions).Section 7 is on the use of multimodels as component models in couplings.Section 8 is on types of inputs and their use in couplings as well as on exter-nal inputs to simulation studies.In Sec.9,conclusions and future work for complex systems are outlined.Especially,the values of simulation systems engineering as well as understanding and avoidance of misunderstanding in cognitive and emotive simulations are stressed.Appendix A is a list of almost 50 types of couplings and Appendix B lists over 50 terms related with couplings in modeling and simulation.To show the richness of“input”concept which is important in specification of input/output relations of component models,Appendix C lists almost 150 types of inputs.Information shared in this article may be useful in developing advanced modeling and simulation software,tools and environments.

A Component-Based Debugging Approach for Detecting Structural Inconsistencies in Declarative Equation Based Models

Object-oriented modeling with declarative equation based languages often unconsciously leads to structural inconsistencies. Component-based debugging is a new structural analysis approach that addresses this problem by analyzing the structure of each component in a model to separately locate faulty components. The analysis procedure is performed recursively based on the depth-first rule. It first generates fictitious equations for a component to establish a debugging environment, and then detects structural defects by using graph theoretical approaches to analyzing the structure of the system of equations resulting from the component. The proposed method can automatically locate components that cause the structural inconsistencies, and show the user detailed error messages. This information can be a great help in finding and localizing structural inconsistencies, and in some cases pinpoints them immediately.

Effect of Morphology on Word Acquisition: An Investigation on the Acquisition of Psych Adjectives

Morphology is said to play a role in word acquisition. English psych adjectives are identified as a category of words with morphological complex gradience, which consists of free morphs, derivatives and inflections. Due to their morphological features, psych adjectives were considered the ideal candidates to test the effect of morphology on word acquisition. This study adopted a within-group research design, where a controlled productive test and a receptive knowledge test were developed and administered to English learners of an intermediate level. Results suggested that acquisition of the inflections was significantly different from that of free morphs and derivatives in the controlled productive test, but no difference was found in the receptive knowledge test. Comparisons of the two tests for the three word groups showed that the only significant difference occurred in the inflection word group. The overall results revealed that learners experienced much more difficulty in acquiring inflectional psych adjectives. In light of the dissociation of associative memory and rule memory, two possible explanations for the learning problems were offered： 1） learners failed to represent the inflections in associative memory, or 2） they have not proceduralized the morphology rules in rule memory.