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An multi-objective discrete particle swarm optimization and simulated annealing (MODPSO-SA) algorithm is proposed to solve the cooperative task allocation for multiple autonomous underwater vehicle (AUV). Through analyzing the task priority sequence constraints and energy consumption, the mathematical model of heterogeneous multi-AUV cooperative task allocation is set up. Aiming at the problem that particle swarm optimization is easy to fall into local extremum, a new multi-objective local search strategy is formed by combining the improved simulated annealing (SA) and shift strategy, which balances the global development ability and local mining ability. The simulation results show that the MODPSO-SA algorithm can get reasonable solution set, which can solve the task assignment of multi-AUV effectively.

Department of Chemistry, Guangxi Normal University, Guilin, Guangxi 541004, P. R. China E-mail : bioinorganicchem@263.net hurx@mailbox.gxnu.edu.cn Analysis Center, Chengdu Branch of Chinese Academy of Science, Chengdu, Sichuan 610041 P. R. China Manuscript received 4 September 2000. revised 15 March 2001, accepted 24 March 2001 The reactions of rare earth picrates with 4,4' -bpy in H2O-CH3CN give compounds [Tm(H2O)4(pic)2]2[Tm(H2O)6(pic)](4,4' -bpy)5(pic)6 (1) and [Gd2(4,4'-bpy)(pic)2( H2O)12](4,4'-bpy)5(H2O)6(pic)4 (2) (4,4'-bpy = 4,4'-bipyridine, pic- = picric anion). Asupramolecular unit cell of compound 1 is assembled by intermolecular hydrogen bond from three independent complex cationswhich arecrystallographically distinguishable. Such units arc bridged in the form of side-by-side by 4,4'-bpy molecules via hydrogenbond to form stair-like chains, and then an elegant 20-network structure. Furthermore, a supramolecular 3D-network is constructedby hydrogenbond formed by uncoordinated picric anion and coordinated water molecules. Both coordinativeand hydrogen bondscontribute to networking in compound 2 based on 4,4'-bpy-bridgcd binuclear units which have been shown to be linked in theform of head-to-tail by double hydrogen-bond bridges of the type Gd-H2O ... 4,4'-bpy ...H2O... H2O-Gd, producing zig-zag chains. Thechains are further extended into hydrogen-bonded 3d network. This generates supramolecular cavities which incorporate some uncoordinatedpicric anions and 4,4' -bpy asguests viahost-guest hydrogen bonding. Magnetic susceptibilities measured for compound2 from 75 to 300 K arc indication of no appreciable magnetic exchange interaction between the adjacent GdIIIions.

Department of Chemistry, Guangxi Normal University, Guilin 541004, People's Republic of China Chengdu Center of Analysis and Determination, Academia Sinica, Chengdu 610015, People's Republic of China Manuscript received 30 August 1999, accepted 26 November 1999 Synthesis and crystal structure determination of the title complex are presented. It shows that the zinc atom located in the distorted tetrahedral coordination, is composed of two nitrogen atoms and two sulfur atoms from the two ligands.