Shuichi Itoh

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A sampling theorem for regular sampling in shift invariant subspaces is established. The sufficient-necessary condition for which it holds is found. Then, the theorem is modified to the shift sampling in shiftinvariant subspaces by using the Zak transform. Finally, some examples are presented to show the generality of the theorem.
where f ( w ) is the Fourier transform of f ( t ) defined by f ( w ) = J, f ( t )e-*”*dt . Unfortunately it is not appropriate for nonband-limited signals. However if we let y = 2 m ~ , m € 2, this problem can be viewed as a special case of sampling in wavelet subspaces with p(t) = sin?rt/nt playing the role of scaling function of MRA {Vm = W ( ~ ( 2 ~ t(More)
This paper proposes an efficient protocol and associate algorithm for group key management in secure multicast. This protocol is based on a hierarchy approach in which the group is logically divided into subgroups. The group key is organized using member secrets assigned to each member and server secrets assigned to each subgroup, and the inverse value of(More)
Intractable diarrhea is a major symptom of immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome and associated with autoantibodies against enterocytes. Although autoimmune enteropathy (AIE)-related 75 kDa antigen (AIE-75) is a prominent autoantigen involved in the enteropathy associated with IPEX syndrome, some patients with this(More)
Abstract— In this paper, a necessary and sufficient condition for sampling in the general framework of shift invariant spaces is derived. Then this result is applied respectively to the regular sampling and the perturbation of regular sampling in shift invariant spaces. A simple necessary and sufficient condition for regular sampling in shift invariant(More)
From the Paley–Wiener 1/4-theorem, the finite energy signal f(t) can be reconstructed from its irregularly sampled values f(k+ k) if f(t) is band-limited and supk j kj < 1=4. We consider the signals in wavelet subspaces and wish to recover the signals from its irregular samples by using scaling functions. Then the way to estimate the upper bound of sup k j(More)
In order to provide a framework for building Web-based distributed PSEs (problem solving environment) on a grid, we have been designing and implementing grid PSE builder. By using grid PSE builder, PSE providers can easily build a PSE using existing large scale scientific-engineering application as PSE components, without specialized knowledge about Web(More)
We propose a method of predicting the number of requests for video titles in an on-demand video delivery system considering their time dependency. To handle many heterogeneous video requests in a video streaming delivery network system using video servers, it is effective to introduce video caching systems in the network system. For the cache system design(More)