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In this paper, we present a simple permission-based fair stabilizing solution to the - exclusion problem in tree networks. The -exclusion problem is a generalization of the mutual exclusion problem where processes, instead of 1, are allowed to use a shared resource (enter the critical section) simultaneously. The proposed algorithm is optimal in terms of waiting times of processes to enter critical sections, i.e., between two entries of a process to its critical section, no other process can enter its critical section more than once after stabilization. Since our algorithm is stabilizing, it does not require initialization and withstands transient faults. The stabilization time of the algorithm is rounds and the waiting time is , where h and n are the height and the size of the tree, respectively. In addition, this algorithm satisfies all the requirements of the -exclusion problem: and liveness. [ABSTRACT FROM AUTHOR]

In this paper, we design and implement a P2P cooperative proxy caching system based on a novel P2P cooperative proxy caching scheme. To effectively locate the cached web documents, a TTL-based routing protocol is proposed to manage the query and response messages in the P2P cooperative proxy cache system. Furthermore, we design a predict query-route algorithm to improve the TTL-based routing protocol by adding extra information in the query message packets. To select a suitable cache replacement algorithm for the P2P cooperative proxy cache system, three different cache replacement algorithms, LRU, LFU and SIZE, are evaluated using web trace based performance studies on the implemented P2P cooperative proxy cache system. The experimental results show that LRU is an overall better cache replacement algorithm for the P2P proxy cache system although SIZE based cache replacement approach produces slightly better cache hit ratio when cache size is very small. The performance studies also demonstrate that the proposed message routing protocols significantly improve the performance of the P2P cooperative proxy cache system, in terms of cache hit ratio, byte hit ratio, user request latency, and the number of query messages generated in the proxy cache system, compared to the flooding based message routing protocol. [ABSTRACT FROM AUTHOR]

This paper gives an application of exclusive-or sum-of-products (ESOP) expressions to designing cryptographic protocols. That is, this paper deals with secure computations in a minimal model, and gives a protocol which securely computes every function by means of the techniques of ESOP expressions. The communication complexity of our protocol is proportional to the size of an obtained multiple-valued-input ESOP expression. Since the historical research on minimizing ESOP expressions is now still active, our protocol will "automatically" turn to an efficient one as this research progresses. Thus, we hope that the existence of our cryptographic protocol would motivate further research on minimizing ESOP expressions. [ABSTRACT FROM AUTHOR]