10509424
A Simply Typed Context Calculus with First-class Environments
We introduce a simply typed λ-calculus λϰƐ" which has both contexts and environments as first-class values. In λϰƐ", holes in contexts are represented by ordinary variables of appropriate types and hole filling is represented by the functional application together with a new abstraction mechanism which takes care of packing and unpacking of the term which is used to fill in the holes of the context. λϰƐ" is a conservative extension of the simply typed λβ-calculus, enjoys subject reduction property, is confluent and strongly normalizing. 
 
The traditional method of defining substitution does not work for our calculus. So, we also introduce a new method of defining substitution. Although we introduce the new definition of substitution out of necessity, the new definition turns out to be conceptually simpler than the traditional definition of substitution.
1580777
Classical Brouwer-Heyting-Kolmogorov Interpretation
The Brouwer-Heyting-Kolmogorov interpretation explains the meaning of logical operations as operators that construct proofs from proofs of the operands. The BHK interpretation is usually understood as giving intuitionistic interpretation for the logical operators, but, as pointed out by Troelstra and van Dalen [12], it is possible to understand the BHK interpretation classically. We elaborate this idea and develop a classical theory of proofs as abstract mathematical entities where the truth of a proposition becomes equivalent to the existence of proofs of the proposition.
43544513
Conservativeness of Lambda over lambda-sigma-Calculus
8686702
Theory of Judgments and Derivations
We propose a computational and logical framework NF (Natural Framework) which is suitable for presenting mathematics formally. Our framework is an extendable framework since it is open-ended both computationally and logically in the sense of Martin-Lof's theory or types. NF is developed in three steps. Firstly, we introduce a theory of expressions and schemata which is used to provide a universe for representing mathematical objects, in particular, judgments and derivations as well as other usual mathematical objects. Secondly, we develop a theory of judgments within the syntactic universe of expressions. Finally, we introduce the notions of derivation and derivation game and will show that we can develop mathematics as derivation games by regarding mathematics as an open-ended process of defining new concepts and deriving new judgments. Our theory is inspired by Martin-Lof's theory of expressions and Edinburgh LF, but conceptually much simpler. Our theory is also influenced by Gentzen's natural deduction systems.
1796136
Strong normalizability of the non-deterministic catch/throw calculi
The catch/throw mechanism in Common Lisp provides a simple control mechanism for non-local exits. We study typed calculi by Nakano and Sato which formalize the catch/throw mechanism. These calculi correspond to classical logic through the Curry-Howard isomorphism, and one of their characteristic points is that they have non-deterministic reduction rules. These calculi can represent various computational meaning of classical proofs. This paper is mainly concerned with the strong normalizability of these calculi. Namely, we prove the strong normalizability of these calculi, which was an open problem. We first formulate a non-deterministic variant of Parigot's λμ-calculus, and show it is strongly normalizing. We then translate the catch/throw calculi to this variant. Since the translation preserves typing and reduction, we obtain the strong normalization of the catch/throw calculi. We also briefly consider second-order extension of the catch/throw calculi. Copyright 2002 Elsevier Science B.V
10817469
COMPaS: A Pentium Pro PC-based SMP Cluster and Its Experience
We have built an eight node SMP cluster called COMPaS (Cluster Of Multi-Processor Systems), each node of which is a quadprocessor Pentium Pro PC. We have designed and implemented a remote memory based user-level communication layer which provides lowover-head and high bandwidth using Myrinet. We designed a hybrid programming model in order to take advantage of locality in each SMP node. Intra-node computations utilize a multi-threaded programming style (Solaris threads) and inter-node programming is based on message passing and remote memory operations. In this paper we report on this hybrid shared memory/distributed memory programming on COMPaS and its preliminary evaluation. The performance of COMPaS is affected by data size and access patterns, and the proportion of inter-node communication. If the data size is small enough to all fit on the cache, parallel efficiency exceeds 1.0 using the hybrid programming model on COMPaS. But the performance is limited by the low memory bus bandwidth of PC-based SMP nodes for some memory intensive workloads.
28509315
Development of a method to construct three-dimensional finite element models of thoracic aortic aneurysms from MRI images
Most patients die when thoracic aortic aneurysms rupture. In order to avoid the ruptures, the aneurysms are replaced with aortic prostheses when their maximum diameter exceeds 5 cm. Because this criterion is based on the experiences, some aneurysms rupture even if the diameters are smaller than this criterion. To treat the aneurysm properly, it is necessary to find out the new criterion. The rupture is thought to have a close relationship with the stress in the wall. Hence, there is much research about the stress, but this research uses the straight tube model. The model shape does not seem appropriate to a thoracic aorta shape. Hence, we developed the method to construct three-dimensional finite element models of thoracic aortic aneurysms from MRI images.
31025719
Programming with Distributed Data Structure for EM-X Multiprocessor
The EM-X, a new generation of EM-4, is a distributed memory multiprocessor which has a dataflow mechanism. The dataflow mechanism enables a fine-grain communication packet through the network to invoke and synchronize the thread of control dynamically with very small overhead. In this paper, we present programming with a distributed data structure shared by threads, and its implementation for the EM-X multiprocessor. Threads may communicate and coordinate by leaving data in a global address space. A new distributed data structure, called the Q-structure, is introduced. This can be used as a shared queue in the context of thread-based programming in the parallel programming language EM-C. We also discuss related distributed data structures including Liuda'a tuple space, synchronizing data structure in the dataflow computation model.
43068454
EM-C: Programming with Explicit Parallelism and Locality for EM-4 Multiprocessor
EM-C is a parallel extension of the C programming language designed for efficient parallel programming in the EM-4 multiprocessor.
206591385
A Parallel Method for Large Sparse Generalized Eigenvalue Problems by OmniRPC in a Grid Environment
In this paper we present a parallel method for finding several eigenvalues and eigenvectors of a generalized eigenvalue problem Ax = λBx, where A and B are large sparse matrices. A moment-based method by which to find all of the eigenvalues that lie inside a given domain is used. In this method, a small matrix pencil that has only the desired eigenvalues is derived by solving large sparse systems of linear equations constructed from A and B. Since these equations can be solved independently, we solve them on remote hosts in parallel. This approach is suitable for master-worker programming models. We have implemented and tested the proposed method in a grid environment using a grid RPC (remote procedure call) system called OmniRPC. The performance of the method on PC clusters that were used over a wide-area network was evaluated.