A message from the managing editor

A message from the managing editor     

A method of program transformation between variable sharing and message passing

There have been proposed and used many programming concepts for realizing interprocess communication and synchronization, and two fundamental categories among them are variable sharing (e.g. semaphores) and message passing (signals, input/output in CSP and redezvous in Ada). The aim of this paper is to investigate the relationship between these two mechanisms, and in particular, program transformation between them. We here propose a transformation method between parallel programs written in each of these two, which uses transformation schemes named monitor transformations. We exhibit the method by showing through a chain of program transformations the equivalence of two versions of a parallel algorithm called dynamic sorting array.     

The message is the medium

We are exploring the use of visual imagery which simultaneously provides the content and control of web-based interactive services. We describe four unconventional web-based services we have implemented for: messaging, a bulletin board, broadcast messages, and browsing through a set of hyperlinked objects. We implement each service using a real-world metaphor which serves as the basis for the visual presentation as well as the service itself; thus form and function are tightly coupled. The use of universal imagery eliminates the need for wordy explanations and hence increases accessibility to an international audience. During the course of development, we devised techniques to enhance the shared experiences of the visitors to our sites, including automatically generated 2D animations. These approaches can be applied to a variety of web-sites and are also described.     

Estimation of message source and destination from network intercepts

We consider the problem of estimating the endpoints (source and destination) of a transmission in a network based on partial measurement of the transmission path. Possibly asynchronous sensors placed at various points within the network provide the basis for endpoint estimation by indicating that a specific transmission has been intercepted at their assigned locations. During a training phase, test transmissions are made between various pairs of endpoints in the network and the sensors they activate are noted. Sensor activations corresponding to transmissions with unknown endpoints are also observed in a monitoring phase. A semidefinite programming relaxation is used in conjunction with the measurements and linear prior information to produce likely sample topologies given the data. These samples are used to generate Monte Carlo approximations of the posterior distributions of source/destination pairs for measurements obtained in the monitoring phase. The posteriors allow for maximum a posteriori (MAP) estimation of the endpoints along with computation of some resolution measures. We illustrate the method using simulations of random topologies.     

Provable secure geometrical message mechanism of the session key and recognition the message start token

An algorithm for generating a session key and a message start token is proposed. This algorithm is based on joint integration by subscribers of the N body problem.     

Authenticated encryption schemes with message linkages for message flows

Two efficient authenticated encryption schemes with message linkages are proposed. One is a basic scheme, that it has the better performance in comparison with the all previously proposed schemes in terms of the communication and the computation costs. However, it has a property as same as the previously proposed schemes, that the message blocks can be recovered only after the entire signature blocks have been received. Therefore, the basic scheme is applicable to encrypt all-or-nothing flow. Thus, we improve the basic scheme and also propose a generalized scheme, which allows the receiver to recover the partial message blocks before receiving the entire signature blocks. That is, the receiver may perform the receiving and the recovering processes simultaneously. Therefore, the generalized scheme is applicable to message flows. The generalized scheme requires smaller bandwidth and computational time as compared to the previously proposed authenticated encryption schemes with message linkages for message flows.