Pyramid is a solitaire game, where the object is to remove all cards from both a pyramidal layout and a stock of cards. Two exposed cards can be matched and removed if their values total 13. Any exposed card of value 13 and the top card of the stock can be discarded immediately. We prove that the generalized version of Pyramid is NP-complete.

In order to enhance QoE of audio and video IP transmission, this paper proposes a method for mitigating the spatial quality impairment during burst loss periods over the wireless networks in the video output scheme SCS, which is a QoE-based video output scheme. SCS switches between two common video output schemes: frame skipping and error concealment. The proposed method pauses video output with an undamaged frame during the burst loss period in order not to pause video output on a degraded frame. We perform an experiment with constant thresholds, the table-lookup method, and the proposed method under various network conditions. The result shows that the effect of the proposed method on QoE can differ with the contents and GOP structures.

The Building puzzle is played on an N×N grid of cells. Initially, some numbers are given around the border of the grid. The object of the puzzle is to fill out blank cells such that every row and column contains the numbers 1 through N. The number written in each cell represents the height of the building. The numbers around the border indicate the number of buildings which a person can see from that direction. A shorter building behind a taller one cannot be seen by him. It is shown that deciding whether the Building puzzle has a solution is NP-complete.

Forty Thieves is a solitaire game with two 52-card decks. The object is to move all cards from ten tableau piles of four cards to eight foundations. Each foundation is built up by suit from ace to king of the same suit, and each tableau pile is built down by suit. You may move the top card from any tableau pile to a tableau or foundation pile, and from the stock to a foundation pile. We prove that the generalized version of Forty Thieves is NP-complete.

In this paper, the repeatable hybrid parallel implementation of inverse matrix computation using SMW formula is proposed. The authors' had previously proposed a hybrid parallel algorithm for inverse matrix computation. It is reasonably fast for a one time computation of an inverse matrix, but it is hard to apply this algorithm repeatedly for consecutive computations since the relocation of the large matrix is required at the beginning of each iterations. In order to eliminate the relocation of the large input matrix which is the output of the inverse matrix computation from the previous time step, the computation algorithm has been redesigned so that the required portion of the input matrix becomes the same as the output portion of the previously computed matrix in each node. This makes it possible to repeatedly and efficiently apply the SMW formula to compute inverse matrix in a time-series simulation.