We present a rebound attack on the 4-branch type-2 generalized Feistel structure with an SPS round function, which is called the type-2 GFN-SPS in this paper. Applying a non-full-active-match technique, we construct a 6-round known-key truncated differential distinguisher, and it can deduce a near-collision attack on compression functions of this structure embedding the MMO or MP modes. Extending the 6-round attack, we build a 7-round truncated differential path to get a known-key differential distinguisher with seven rounds. The results give some evidences that this structure is not stronger than the type-2 GFN with an SP round function and not weaker than that with an SPSP round function against the rebound attack.

We present an economical and fault-tolerant load balancing strategy (EFTLBS) based on an operator replication mechanism and a load shedding method, that fully utilizes the network resources to realize continuous and highly-available data stream processing without dynamic operator migration over wide area networks. In this paper, we first design an economical operator distribution (EOD) plan based on a bin-packing model under the constraints of each stream bandwidth as well as each server's CPU capacity. Next, we devise super-operator (SO) that load balances multi-degree operator replicas. Moreover, for improving the fault-tolerance of the system, we color the SOs based on a coloring bin-packing (CBP) model that assigns peer operator replicas to different servers. To minimize the effects of input rate bursts upon the system, we take advantage of a load shedding method while keeping the QoS guarantees made by the system based on the SO scheme and the CBP model. Finally, we substantiate the utility of our work through experiments on ns-3.

A rectifying antenna is one of the most important components for wireless power transmission applications. In our previous papers, some RF-DC conversion circuits with high conversion efficiency at low input power are proposed. However, these RF-DC conversion circuits have some parts of which size depends on operating frequency, so the circuit size becomes large at low operating frequency. And, the composition of these RF-DC conversion circuits is complicated. Therefore, in this paper, a new RF-DC conversion circuit composed of only chip devices is proposed. This circuit has higher conversion efficiency than the previously proposed circuits. And, size reduction of the RF-DC conversion circuit is realized. Moreover, the composition of the circuit is simple, so the circuit size does not depend on operating frequency. For design of the RF-DC conversion circuits, LE-FDTD method is used. The measurement results agree with analytical results of the LE-FDTD method very well, and availability of the LE-FDTD method is discovered. It is shown that LE-FDTD method is a powerful analytical way which can give efficient design of RF-DC conversion circuit with high conversion efficiency.

The Earth will require sustainable electricity sources equivalent to 3 to 5 times the commercial power presently produced by 2050. Solar Power Satellite (SPS) is one option for meeting the huge future energy demand. SPS can send enormous amounts of power to the Earth as the form of microwave (MW). A highly efficient microwave power transmission (MPT) system is needed for SPS. A critical goal of SPS is to maintain highest Beam Efficiency (BE) because the microwaves from SPS will be converted to utility power unlike the MW from communication satellites. Another critical goal of SPS is to maintain Side Lobe Levels (SLL) as small as possible to reduce interference to other communication systems. One way to decrease SLL and increase BE is the edge tapering of a phased array antenna. However, tapering the excitation requires a technically complicated system. Another way of achieving minimum SLL is with randomly spaced element position but it does not guarantee higher BE and the determination of random element position is also a difficult task. Isosceles Trapezoidal Distribution (ITD) edge tapered antenna was studied for SPS as an optimization between full edge tapering and uniform amplitude distribution. The highest Beam Collection Efficiency (BCE) and lowest SLL (except maximum SLL) are possible to achieve in ITD edge tapering and ITD edge tapered antenna is technically better. The performance of ITD is further improved from the perspective of both Maximum Side Lobe Level (MSLL) and BE by using unequal spacing of the antenna elements. A remarkable reduction in MSLL is achieved with ITD edge tapering with Unequal element spacing (ITDU). BE was also highest in ITDU. Determination of unequal element position for ITDU is very easy. ITDU is a newer concept that is experimented for the first time. The merits of ITDU over ITD and Gaussian edge tapering are discussed.

Minimizing the Side Lobe Level (SLL) and attain highest achievable Beam Collection Efficiency (BCE) is a critical goal for Solar Power Station/Satellite (SPS). If all antennas are uniformly excited then the main beam will carry only a part of the total energy due to the higher SLL. SLL is decreased and BCE is increased by adopting edge tapering for SPS. But edge tapering is a complex technical problem for SPS. So an optimization is needed between uniform amplitude distribution and edge tapering system. We have derived a new method of edge tapering called Isosceles Trapezoidal Distribution (ITD) edge tapering. Only a small number of antennas from each side of the phased array antenna are tapered in this method. ITD edge tapering is almost uniform so it is technically better. We have compared different amplitude distribution systems; uniform, Gaussian, Dolph-Chebyshev and the newly derived ITD method. The SLL reduction in ITD is even lower than those of other kinds of edge tapering. Therefore the amount of losing power in the SLL in ITD is lower. As a result the interference level becomes lower and BCE becomes higher in this method. The higher BCE and better SLL performance than those with uniform distribution can be achieved in ITD with phase error and under unit failed condition.

GPS (Global Positioning System) is 3D positioning system which uses satellite signals, and it is used in various situations. The number of GPS satellites that we can see changes in measurement and the degree of error is increased between measurement points. Our aim is to reduce the degree of error through the experiment and simulation and, as a result, we have succeeded in reducing error in most of the examples.

We developed a phase controlled magnetron (PCM) with high DC-RF conversion efficiency and with phase control to steer a microwave beam in order to realize the final space Solar Power Station (SPS) system. For the PCM, we use injection locking technique and PLL feedback to anode current. We can stabilize and control a frequency and a phase of a microwave of the PCM. However, we have a power loss after the PCM for the SPS use because of a size of the antenna (> km) and of a microwave power (> GW). In order to decrease power loss after PCM, we newly propose a concept of "sub phase shifter" which can change only 1 or 2 bits of a phase and has low loss. We can keep high beam collection efficiency when we control a beam to a twice larger direction in the SPS system. With this concept, we developed a PCM array called SPORTS (Space Power Radio Transmission System) in FY2000 and FY2001 in Kyoto University.

Since semiconductor memory chip has been growing rapidly in its capacity, memory testing has become a crucial problem in RAMs. This paper proposes a new RAM test algorithm, called generalized marching test (GMT), which detects static and dynamic pattern sensitive faults (PSF) in RAM chips. The memory array with N cells is partitioned into B sets in which every two cells has a cell-distance of at least d. The proposed GMT performs the ordinary marching test in each set and finally detects PSF having cell-distance d. By changing the number of partitions B, the GMT includes the ordinary marching test for B1 and the walking test for BN. This paper demonstrates the practical GMT with B2, capable of detecting PSF, as well as other faults, such as cell stuck-at faults, coupling faults, and decoder faults with a short testing time.