Case based reasoning (CBR) retrieval operations with partial ordering similarity measures have been implemented in LINDA to extract generic operations and identify potential parallelism in CBR. Mapping and reduction operations, and constraint matching versions of all retrieval operations were identified, then implemented in LINDA. Their operational semantics were expressed in terms of the CHAM for Liam (LINDA abstract machine) and refined to produce the basis for efficient, parallel implementations of the operations as additional LINDA instructions. The implementation of the constraint matching operations suggests the use of eval() to achieve process migration in distributed systems, and default local tuple space interaction. It as suggested that the constraint matching instructions replace the basic matching retrieval instructions, as they extend the functionality of the matching process by maintaining atomicity of matching and moving the constraint function from the program to the LINDA kernel.
Campbell's Lenient Unified Model of Parallel Systems (CLUMPS) is presented, a candidate model of parallel computation which aims to tackle and solve the deficiencies of existing candidate models. It is shown that all parallel computers can perform the same computations, but differ in their ability to support different communication loads. This conclusion is reflected in the definition of CLUMPS which aims to be architecture-independent, reflective of execution costs, expressible and intellectually manageable. It also reflects the principle that if a problem can be partitioned into regions, and if those regions are preserved in the mapping of the algorithm to the architecture then greater communication efficiency can be achieved than if the locality was not preserved. Algorithmic skeletons are seen as high level language constructs capturing parallelism, hence communication, in a regular and manageable manner. Such skeletons can be costed in terms of CLUMPS to provide parallel performance prediction.< >
Several studies have indicated that additional genes in the major histocompatibility complex (MHC) region, other than the class II genes HLA‐DQB1 and ‐ DRB1 (the IDDM1 locus), may contribute to susceptibility and resistance to type 1 diabetes. The relative magnitude of these non‐ DR/DQ effects is uncertain and their map location is unknown owing to the extraordinary linkage disequilibrium that extends over the 3.5 Mb of the MHC. The homozygous parent test has been proposed as a method for detection of additional risk factors conditional on HLA‐DQB1 and ‐ DRB1 . However, this method is inefficient since it uses only parents homozygous for the primary disease locus, the DQB1‐DRB1 haplotype. To overcome this limitation, Conditional ETDT was used in the present report to test for association conditional on the DQB1‐DRB1 haplotype, thereby allowing all parents to be included in the analysis. First, we confirm in UK and Sardinian type 1 diabetic families that allelic variation at HLA‐DRB1 has a very significant effect on the association of DQB1 and vice versa . The Conditional ETDT was then applied to the HLA TNF (tumour necrosis factor) region and microsatellite marker D6S273 region, both of which have been reported to contribute to IDDM1 independent of the HLA‐DQB1‐DRB1 genes. We found no evidence for a major role for either of these two regions in IDDM1 .
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