Abstract This paper proposes a novel shadow removal technique for cooperative projection system based on spatiotemporal prediction. In our previous work, we proposed a distributed feedback algorithm, which is implementable in cooperative projection environments subject to data transfer constraints between components. A weakness of this scheme is that the compensation is conducted in each pixel independently. As a result, spatiotemporal information of the environmental change cannot be utilized even if it is available. In view of this, we specifically investigate the situation where some of the projectors are occluded by a moving object whose one‐frame‐ahead behaviour is predictable. In order to remove the resulting shadow, we propose a novel error propagating scheme that is still implementable in a distributed manner and enables us to incorporate the prediction information of the obstacle. It is demonstrated theoretically and experimentally that the proposed method significantly improves the shadow removal performance in comparison to the previous work.

This paper proposes a novel radiometric compensation technique for cooperative projection system based-on distributed optimization. To achieve high scalability and robustness, we assume cooperative projection environments such that 1. each projector does not have information about other projectors as well as target images, 2. the camera does not have information about the projectors either, while having the target images, and 3. only a broadcast communication from the camera to the projectors is allowed to suppress the data transfer bandwidth. To this end, we first investigate a distributed optimization based feedback mechanism that is suitable for the required decentralized information processing environment. Next, we show that this mechanism works well for still image projection, however not necessary for moving images due to the lack of dynamic responsiveness. To overcome this issue, we propose to implement an additional feedforward mechanism. Such a 2 Degree Of Freedom (2-DOF) control structure is well-known in control engineering community as a typical method to enhance not only disturbance rejection but also reference tracking capability, simultaneously. We theoretically guarantee and experimentally demonstrate that this 2-DOF structure yields the moving image projection accuracy that is overwhelming the best achievable performance only by the distributed optimization mechanisms.

Power-performance efficiency is still remaining a primary concern for microprocessor designers. One of the sources of power inefficiency for recent LSI chips is increasing leakage power consumption. Power-gating is a well known technique to reduce leakage power consumption by switching off the power supply to idle logic blocks. Recently, fine-grained power-gating is emerged as a technique to minimize leakage current during the active processor cycles by switching on and off a logic blocks in much finer temporal/spatial granularity. Though fine-grained power-gating is useful, a comprehensive evaluation and analysis has not been conducted on a real LSI chips. In this paper, we evaluate fine-grained run-time power-gating for microprocessors' functional units using a real embedded microprocessor. We also introduce an architecture and compiler co-operative power-gating scheme which mitigates negative power reduction caused by the energy overhead associated with finegrained power-gating. The experimental results with a fabricated core shows that a hardware-based scheme saves power consumption of functional units by 44% and hardware compiler co-operative scheme further improves power efficiency by 5.9% when core temperature is 25 ˚C.

In this paper, we propose an intervehicle information dissemination protocol called received message-dependent protocol (RMDP) that propagates the preceding traffic information to the following vehicles and discuss its performance. The proposed protocol autonomously changes the dissemination interval, depending on the number of reception messages and detected reception errors, in order to avoid message collision among vehicles. We have constructed a realistic simulation environment of intervehicle communication by combining a traffic-flow simulator and an ad hoc network simulator. Our simulation results show that, by using RMDP, a lot of vehicles can acquire their preceding traffic information within short periods at both the conditions with light and heavy traffic. In addition, we have also shown that selection policy of disseminated data affects preceding-traffic-information acquisition time. Each vehicle holds other vehicles' traces for some period. Depending on the number of preserved other vehicles' traces and their preserved periods, the propagation ratio of the preceding traffic information varies. Some simulation results are explained.

In this paper, we propose an inter-vehicle ad-hoc communication protocol called RMDP (received message dependent protocol) which disseminates and propagates the preceding traffic information to the following vehicles, and discuss its performance. Our proposed protocol dynamically changes the dissemination interval depending on the number of reception messages for avoiding message collision in heavy traffic jam conditions. We design the parameters of the protocol based on the simulation results. Our simulation results show that by using RMDP, a lot of vehicles can acquire the preceding traffic information within very short periods. In addition, we have also shown that selection of disseminate data affects preceding traffic information acquiring time. Each vehicle holds other vehicles' tracks for some period. Depending on the number of preserved other vehicles' tracks and their preserved period, propagation ratio of the preceding traffic information varies. Some simulation results are explained.