Cheng-Chia Chen

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This paper is concerned with the Computational complexity of the following problems for various modal logics L: (1). The L-deducibility problem: given a finite set of ~ormulas S and a formula A, determine if A is in the modal theory THL(S) formed With all theorems of the modal logic L as logical axioms and with all members of S as proper axioms. (2). The(More)
Since the invention of Prolog, a programming language based on classical first-order logic, many people have tried to extend it using similiar ideas and redefine the semantics of the extended Prolog in terms of nonclassical logics [3,5,81. The success of a programming language based on nonclassical logics usually lies in the new definiton of Horn formulas(More)
One of the key functions to popularize 3D content services on virtual environments is on the extensibility of the underlying system. In our previous work, we had implemented an extensible Multi-User Virtual Environment (MUVE) called IMNet which features plug-in modules for various application purposes. This feature is enabled by adopting the eXtensible(More)
This study examined the effect of Medicare (Part D) implementation on health outcomes among U.S. older adults. Study participants were initially extracted from the 2004-2008 Health and Retirement Study (HRS). Data from respondents who further participated in the HRS 2005-2007 Prescription Drug Study were analyzed (N = 746). This was a retrospective pre-post(More)
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