Modeling and simulation using the compositional interchange format for hybrid systems

One of the major challenges towards a broad industrial acceptance of hybrid systems techniques and tools is the large number of distinct modeling formalisms and the resulting manual effort for the tool-based solution of many complex design or analysis tasks. A promising approach to achieve inter-operability between hybridsystems tools is to develop automatic translations of their formalisms via a general interchange format with sufficiently rich syntax and semantics. This paper gives an intuitive introduction to such a formalism, the Compositional Interchange Format (CIF) for general hybrid systems, that was recently developed within the European Network of Excellence HYCON. The concepts of the CIF are illustrated using an interesting example,the hybrid model of a supermarket refrigeration system. This system exhibits both, nonlinear DAE dynamics as well as significant discrete dynamics, and serves as a challenging case study for hybrid control techniques in several European research projects. Furthermore, the CIF tool set that provides simulation and visualization capabilities is introduced

A hybrid language for modeling, simulation and verification

The ¿ language is a hybrid language for modeling, simulation and verification. As a result of the recently completed formal semantics, the language now consists of a number of orthogonal operators that operate on all process terms, including differential algebraic equations. The same ¿ model can be used for simulation and verification. Verification is possible after a straightforward syntactical translation of the model. Simulation related information is clearly separated from the other statements

Fluid-Electrolyte Balance Associated with Tennis Match Play in a Hot Environment

Twenty (12 male and 8 female) tennis players from two Division I university tennis teams performed three days of round-robin tournament play (i.e., two singles tennis matches followed by one doubles match per day) in a hot environment (32.2 ±and 53.9 ± 2.4% rh at 1200 hr), so that fluid-electrolyte balance could be evaluated. During singles play, body weight percentage changes were minimal and were similar for males and females (males -1.3 ± 0.8%, females -0.7 ± 0.8%). Estimated daily losses (mmol ·) of sweat sodium (Na+) and potassium (K+) (males,158.7,31.3; females,86.5,18.9) were met by the players' daily dietary intakes (mmol ·) of these electrolytes (males,279.1 ± 109.4,173.5 ± 57.7; females,178.9 ± 68.9,116.1 ± 37.5). Daily plasma volume and electrolyte (Na+,) levels were generally conserved, although, plasma [Na+] was lower (p< .05) on the morning of Day 4. This study indicated that these athletes generally maintained overall fluid-electrolyte balance, in response to playing multiple tennis matches on 3 successive days in a hot environment, without the occurrence of heat illness