Computational aspects of the F. E. M Solutions of the convective transport equations:∂tu+∇·(-k∇u+bu)=for∇·(-k∇u+bu)=f are described. Substructured Iteration Methods and Preconditioned LU & Conjugate Gradient Methods are feasible to overcome the memory neck of the computers. ICCG by Meijerink and Van der Vorst are applied to the 3 dimensional ∇·(-k∇u)=f with variable diffusion coefficient k and compared to the SOR, SLOR, and Pure CG Methods.

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An expert system DISKET has been developed at JAERI to apply knowledge engineering techniques to the transient diagnosis of nuclear power plant. The first version of DISKET programmed in UTILISP has been developed with the main-frame computer FACOM M-780 at JAERI. The LISP language is not suitable for on-line diagnostic systems because it is highly dependent on computer to be used and requires a large computer memory. The large mainframe computer is also not suitable because there are various restrictions as a multi-user computer system. The second version of DISKET for a practical use has been developed in FORTRAN to realize on-1ine real time diagnoses with limited computer resources.
These two versions of DISKET with the same knowledge base have been compared in running capability, and it has been found that the LISP version of DISKET needs more than two times of memory and CPU time of FORTRAN version. From this result, it is shown that this approach is a practical one to develop expert systems for on-line real time diagnosis of transients with limited computer resources.

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Cheney によって考案されたコピーGC はオブジェクトを幅優先順にコピーするため，多くの場合，参照の空間的局所性が低下し，キャッシュやのミスを増加させる．そこで深さ優先順にコピーする方式も提案されているが，局所性の改善は限定的だった．本研究ではオブジェクトを階層的にグループ化してコピーすることで局所性を向上させる．また，限られた作業領域でできるだけ多くの部分に階層的グループ化を適用する方式を提案する．

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