Cost comparison of Colorless and Directionless (CD) or Colorless, Directionless, and Contention-less (CDC) ROADM architectures with different TransPonder Aggregator (TPA) configuration was performed. It is clarified that the most economic TPA-based ROADM architecture depends on network details such as add/drop ratio.

In the virtual ball game, such as soccer, football, basketball and hockey etc. in a virtual space, "pass" plays have a significant meaning for players to build up their games. Goodness of a passes course and its velocity is continuously varied, both spatially and temporarily by all motions of ally player avatars and opponent player avatars attending in the game. Because of this, a significant pass between the avatars may not easily be able to be analyzed and generated by the computer systems in real-time. In this paper, we propose a new algorithm that can realize this computation in real-time. Concretely, a real-time detection of a "space" or an "open space" for every avatar by using the idea of "AtoZ (Allocated Topographical Zone)" that Kawano et al., have already proposed. Based on this idea, we compute the reachable pass vector to any avatar in the game. Moreover, the space where a player can receive a pass given by the pass vector, prior to any other player, is defined as an "exclusively reachable pass zone" for the receiver, and is able to be computed by the algorithm.

In this paper, we studied the relationship between the accuracy of the dead reckoning data and the update interval in a distributed virtual environment (DVE). We have already shown that numerical analysis can be applied to the dead reckoning data between frames using parametrics calculated from the data over the last several frames based on polynomial models. Based on the above polynomial models, we proposed the new dead reckoning method to extrapolate the attribute data which arrives at discrete time period. We showed that theoretical models which approximate the statistical error of dead reckoning data can be formulated based on parameters such as the update interval and changes in the data. Theoretical models showed that the average error of proposed method is less than that of current method. Finally, we evaluate the validity of the proposed method with the comparison of current method by conducting experiments with the pen motion of a series of letters written by human. We confirmed that the proposed method can decrease the extrapolation error in comparison with current method in average

In this paper, the authors aim to analyze the error of dead reckoned data generated from received data in a discrete temporal axis in a distributed virtual environment (DVE). That is, compared with the data received in continuous time, data acquired in discrete time has a certain degradation or uncertainty of information. Our way of analysis is to introduce a mathematical model of this degradation with regard to the metrics of the temporal interval. We introduced polynomial models for dead reckoning method between frames using parametrics calculated from the data over the last several frames. By employing the method of error analysis of a numerical analysis to the above polynomial models, we formulate theoretical models which approximate the statistical error of dead reckoned data based on parameters such as the update interval and changes in the data. This study enables the discussion on the optimality of the update interval in a DVE using dead reckoning. Finally, we evaluate the adaptability of the theoretical model by conducting simulation experiments generated by pen motion of writing string of letters by human. As a result, we confirm that the proposed theoretical model closely approximates the average error in the simulation

This paper aims to study how to gain consistency of the state in a DVE (distributed virtual environment) with lag, under the condition of peer-to-peer architecture. That is, we study how to reduce in real-time the difference of the DVE state between peers caused by transmission lag or update interval, and how to control the shared object in the online field game. Specifically, the priority field called allocated topographical zone (AtoZ) and mutual prediction protocol is used in peer-to-peer DVE. Moreover considering the critical case (the inconsistent phenomena) caused by the network latency between peers, stricter ownership determination algorithm called the dead zone is introduced. Using these three protocols in combination, a robust and effective scheme is realized. As an example of the application using the protocols, a real-time networked air-hockey is implemented for evaluation of the influence on interactivity and consistency.