We have developed a three-dimensional eye movement simulator that simulates eye movement. The simulator allows us to extract the instantaneous eye movement rotation axes from clinical data sequences. It calculates the plane formed by rotation axes and displays it on an eyeball with rotation axes. It also extracts the innervations for eye muscles. The developed simulator is mainly programmed by a CG programming language, OpenGL. First, the simulator was applied to saccadic eye movement data in order to show the so-called Listing's plane on which all hypothetical rotation axes lie. Next, it was applied to clinical data sequences of two patients with benign paroxysmal positional vertigo (BPPV). Instantaneous actual rotation axes and innervations for eye muscle extracted from data sequences have special characteristics. These results are useful for the elucidation of the mechanism of vestibular symptoms, particularly vertigo.

In forthcoming sensor networks, a multitude of sensor nodes deployed over a large geographical area for monitoring traffic, climate, etc. are expected to become an inevitable infrastructure. Clustering algorithms play an important role in aggregating a large volume of data that are produced continuously by the huge number of sensor nodes. In such networks, equal-sized multi-hop clusters which include an equal number of nodes are useful for efficiency and resiliency. In addition, scalability is important in such large-scale networks. In this paper, we mathematically design a decentralized equal-sized clustering algorithm using a partial differential equation based on the Fourier transform technique, and then design its protocol by discretizing the equation. We evaluated through simulations the equality of cluster sizes and the resiliency against packet loss and node failure in two-dimensional perturbed grid topologies.

The number of SIP-based services provided by network service providers (NSPs) is increasing. SIP allows NSPs to control services and to collect the information relating to charging for the usage of their customer communications. Monitoring SIP messages (exchanged between SIP proxy servers and user terminals) is vital for providing the stable SIP-based services. Monitoring SIP messages enables NSPs to quickly discover a fault location where SIP messages are lost, and to determine the subsequent recovery solutions. This paper proposes a lightweight method for determining the location of SIP message loss through relationships based on the SIP's retransmission mechanism. Numerical analyses show that the proposed method can locate the lossy links of SIP messages with a low probability of detection failure.

This paper presents an area-effective bandwidth enhancement technique using interwoven inductors. Inductive peaking is a common practice for bandwidth enhancement, however the area overhead of inductors is a serious issue. We implement six or four inductors into an interwoven inductor. Furthermore parasitics of the inductors can be reduced. The proposed inductor is applied to a laser-diode driver in a 0.18 µm CMOS. Compared to conventional shunt-peaking, the proposed circuit achieves 1.6 times faster operation and 60% reduction in power consumption under the condition for the same amount of data transmission and the LD driving current. The interwoven inductor can reduce the circuit area by 26%. Parasitic capacitance in interwoven inductor is discussed. Simulation results reveal that line-to-line capacitance is a significant factor on bandwidth degradation.

In the gauge of IMT-2000, Mobile IP based location management is standardized. The cellular network of IMT-2000 holds many users and covers a large area. In large-scale Mobile IP networks, such as IMT-2000, a foreign agent may manage many mobile nodes by the visitor list and its forwarding performance degrades owing to the list search overload. In this paper, we propose a fast data transfer method in Mobile IP networks by reducing the load of the search processes on the foreign agent using cooperation between mobility agents. In our experiments, we measured the packet forwarding performance and the packet forwarding process time. The results indicate the possibility of the performance degradation owing to the part of the registered mobile nodes in the visitor list. We verify that the foreign agent using our method can forward all the received packets on Fast Ethernet LAN when one million entries are recorded in the visitor list.

This paper proposes a design technique to reduce the power dissipation of CML driver for on-chip transmission-lines. CML drivers can operate at higher frequency than conventional static CMOS logic drivers. On the other hand, the power dissipation is larger than that of CMOS static logic drivers. The proposed method reduces the power dissipation by using an impedance-unmatched driver instead of the conventional impedance-matched driver. Measurement results show that the proposed method reduces the power dissipation by 32% compared with a conventional design at 12.5 Gbps.

In the near future, decentralized network systems consisting of a huge number of sensor nodes are expected to play an important role. In such a network, each node should control itself by means of a local interaction algorithm. Although such local interaction algorithms improve system reliability, how to design a local interaction algorithm has become an issue. In this paper, we describe a local interaction algorithm in a partial differential equation (or PDE) and propose a new design method whereby a PDE is derived from the solution we desire. The solution is considered as a pattern of nodes' control values over the network each of which is used to control the node's behavior. As a result, nodes collectively provide network functions such as clustering, collision and congestion avoidance. In this paper, we focus on a periodic pattern comprising sinusoidal waves and derive the PDE whose solution exhibits such a pattern by exploiting the Fourier method.