This paper develops a framework to support trace theoretic verification of timed circuits and systems. A theoretical foundation for classifying timed traces as either successes or failures is developed. The concept of the semimirror is introduced to allow conformance checking thus supporting hierarchical verification of timed circuits and systems. Finally, we relate our framework to those previously proposed for timing verification.

In 1998, Fan and Lei proposed a partially blind signature scheme that could reduce the computation load and the size of the database for electronic cash systems. In this Letter, we show that their scheme could not meet the untraceability property of a blind signature.

This paper addresses the problem of designing an unconditionally secure conference system that fulfills the requirements of both traceability and dynamic sender. In a so-called conference system, a common key is shared among all authorized users, and messages are encrypted using the shared key. It is known that a straightforward implementation of such a system may present a number of security weaknesses. Our particular concern lies in the possibility that unauthorized users may be able to acquire the shared key by illegal means, say from one or more authorized but dishonest users (called traitors). An unauthorized user who has successfully obtained the shared key can now decrypt scrambled messages without leaving any evidence on who the traitors were. To solve this problem, in this paper we propose a conference system that admits dynamic sender traceability. The new solution can detect traitors, even if the sender of a message is dynamically determined after a shared key is distributed to authorized users. We also prove that this scheme is unconditionally secure.

Elliptic curve cryptosystems are based on the elliptic curve discrete logarithm problem (ECDLP). If elliptic curve cryptosystems avoid FR-reduction and anomalous elliptic curve over Fq, then with current knowledge we can construct elliptic curve cryptosystems over a smaller definition field. ECDLP has an interesting property that the security deeply depends on elliptic curve traces rather than definition fields, which does not occur in the case of the discrete logarithm problem (DLP). Therefore it is important to characterize elliptic curve traces explicitly from the security point of view. As for FR-reduction, supersingular elliptic curves or elliptic curve E/Fq with trace 2 have been reported to be vulnerable. However unfortunately these have been only results that characterize elliptic curve traces explicitly for FR- and MOV-reductions. More importantly, the secure trace against FR-reduction has not been reported at all. Elliptic curves with the secure trace means that the reduced extension degree is always higher than a certain level. In this paper, we aim at characterizing elliptic curve traces by FR-reduction and investigate explicit conditions of traces vulnerable or secure against FR-reduction. We show new explicit conditions of elliptic curve traces for FR-reduction. We also present algorithms to construct such elliptic curves, which have relation to famous number theory problems.

The radiation emission in far zones from printed circuit boards (PCBs) is obtained by treating lines on PCBs as transmission lines and calculating the far-field emission due to current distribution on lines. In this paper, we present a more precise circuit model, based on TEM assumption, to decompose the total current into differential-mode current and common-mode current. This circuit model is based on transmission line model, but it considers the effect of ground trace. The finite size ground trace can be viewed as an inductive reactance. A knowledge of the net inductance of the ground trace can aid in the analysis and investigation of PCBs emission. We show the derived equations of the modified transmission lines for the geometrics of practical interest. As time-varying current passes through such ground trace, a voltage drop due to the inductance of the trace will act as a source of the common-mode current. Furthermore, charge stored in capacitance between signal and ground traces will cause the current pulses returning to their source. The magnitudes of currents are slightly unequal in the signal and ground traces, which can cause common-mode current to flow. An unbalanced circuit on a PCB constructed with signal and ground trace pairs will radiate as an asymmetric folded-dipole. By antenna theory, the contribution of differential-mode and common-mode currents to radiated emission of PCBs can be calculated. In addition, comparisons between experimental results and calculation results are also given.

We propose an untraceable electronic money system. Our system uses the partially blind signature based on the discrete logarithm problem, and applies secret key certificates to the payment protocol.

In this paper, an instruction-cache scheme called Multi-Path Tracing is proposed to enhance the trace cache. Paths are classified to improve the trace cache hit ratio by reducing the path conflict and basic blocks are joined to reduce the hardware cost needed to implement the trace cache. Simulation results for various SPEC integer benchmarks show that the proposed scheme increases the hit ratio by more than 25% and the effective fetch size by 10%.

The authors observed the correlation between electromagnetic noise and trace of discharge on surface for various surface areas of Cu in opening copper (Cu)-carbon (C) electrodes. In the case of Cu (anode)-C (cathode), the duration of sporadic burst noise generated by discharge becomes longer when Cu surface area is increased, and trace of discharge (melting area) distribute widely on electrodes. Also the forms of the burst noise in the start of arc are classified, and the traces of discharge correspond to each forms. The forms of the burst noise depend on the pattern which the trace of discharge are formed. As these results, the authors showed the correlation between form of burst noise and trace of discharge on electrode surface.

The second generation of mobile communications is growing rapidly to the third generation due to various communication techniques and the increasing number of users. PCS, the communication method of the third generation, should be able to provide users with various services, independently of the current location. To PCS, the mobility management of users is essential. The mobility management method which has been used has a structural drawback: as the number of users increase, HLR becomes the bottleneck. Everyone is expected to have one terminal in the third generation mobile communications age. Therefore, an enhanced mobility management scheme to reduce the bottleneck of the HLR, should be used in the third generation mobile communications. In this paper, we propose a new mobility management method where the trace of terminals is left in the VLRs, so that a call can be connected by querying only to the VLRs rather than to the HLR when the terminal-terminated-call occurs. The proposed method distributes messages to VLRs and effectively reduce mobility management cost. To estimate overall mobility management cost, we simulated the new method of PCS network. The simulation model is based on the Jackson's network, and makes it possible to estimate mobility management cost of PCS networks. IS-41 and proposed scheme are compared based on the computer simulation. Considering the delay times both in HLR and VLR, and considering both location registration cost and call delivery cost, the proposed modeling method shows the improvement.

In this paper, we propose a new type of authentication system, one-time zero-knowledge authentication system. Informally speaking, in this authentication system, double usage of the same authentication is prevented. Based on these one-time zero-knowledge authentication systems, we propose a new untraceable electronic cash scheme satisfying both untraceability and unreusablity. This scheme overcomes the problems of the previous scheme proposed by Chaum, Fiat and Naor through its greater efficiency and provable security under reasonable cryptographic assumptions. We also propose a scheme, transferable untraceable electronic cash scheme, satisfying transferability as well as the above two criteria. Moreover, we also propose a new type of electronic cash, untraceable electronic coupon ticket, in which the value of one piece of the electronic cash can be subdivided into many pieces.

So far, neuronal dendrites have been characterized as electrically passive cables. However, recent physiological findings have revealed complex dynamics due to active conductances distributed over dendrites. In particular, the voltage-gated calcium and calcium-activated conductances are essential for producing diverse neuronal dynamics and synaptic plasticity. In this paper, we investigate the functional significance of the dendritic calcium-activated dynamics by computer simulations. First, the dendritic calcium-activated responses are modeled in a discrete compartmental form based on the physiological findings. Second, the basic stimulus-response characteristics of the single compartment dendrite model are investigated. The model is shown to reproduce the neuronal responses qualitatively. Third, the spatio-temporal dynamics of the dendrite shafts are modeled by longitudinally connecting 10 single compartments with coupling constants which are responsible for the dendrite thickness. The thick dendrite models, corresponding to proximal dendrites, respond in a spatially cooperative manner to a localized constant or periodic current stimulation. In contrast, the highly activated compartments are forced to be localized in the neighborhood of the stimulation-site in the fine dendrite models corresponding to distal dendrites. These results suggest that dendritic activities are spatially cooperated in a site-dependent manner.

In this paper, Chay's bursting pancreatic β-cell model is updated to include a role for [Ca2+]ER, the luminal calcium concentration in the endoplasmic reticulum (ER). The model contains a calcium current which is activated by voltage and inactivated by [Ca2+]i. It also contains a cationic nonselective current (INS) that is activated by depletion of luminal Ca2+ in the ER. In this model, [Ca2+]ER oscillates slowly, and this slow dynamic drives electrical bursting and the [Ca2+]i oscillations. This model is capable of providing answers to some puzzling phenomena,which the previous models could not (e. g., why do single pancreatic β-cells burst with a low frequency while the cells in an islet burst with a much higher frequency ?). Verification of the model prediction that [Ca2+]ER is a primary oscillator that drives electrical bursting and [Ca2+]i oscillations in pancreatic β-cells awaits experimental testing. Experiments using fluorescent dyes such as mag-fura-2-AM could provide relevant information.

Data reduction method for the earth-satellite-earth laser long-path absorption measurements of atmospheric trace species using the Retroreflector in Space (RIS) on the Advanced Earth Observing Satellite (ADEOS) is described. In the RIS experiment, atmospheric absorption will be measured with single-longitudinal-mode pulsed CO2 lasers and their second and third harmonics. High-resolution absorption spectra are measured by using the Doppler shift of the return beam which is caused by the satellite movement. Vertical profiles of O3 and CH4 are retrieved from the measured absorption line shapes with the inversion method. Also, column contents of CFC12, HNO3, CO2, CO, N2O are derived by the least squares method with assumptions on the relative vertical profiles. Errors in the measurement were evaluated by computer simulation.

We study the correspondence between problem descriptions and requirements specification documents derived from them. Based on the results of this investigation, a model that integrates the problem space and the requirements specification space is developed. This integration is based on a semantic network representation. We also propose a model of the requirements elicitation process that is consistent with our empirical studies of traceability in requirements documents. In this process, analysts derived requirements specifications from incomplete and ambiguous problem descriptions given by customers, identify missing information, completed it, and then decide the system boundaries that define which part of the problem descriptions to implement as the target system. The model can be used to complete problem descriptions given by customers and determine the system boundaries.

For the efficient circuit simulation, several direct/relaxation-based mixed mode simulation techniques have been studied. This paper proposes the combination of selective trace, which is well-known in the logic simulation, with dynamic network separation. In the selective trace method, the time points to be analyzed are selected for each subcircuit. Since the separation technique enables the analysis of each subcircuit independently, it is possible to skip solving the latent subcircuits, according to selective trace. Selecting the time points in accordance with activity of each subcircuit is analogous to multirate numerical integration technique used in the waveform relaxation algorithm.

A high-gain, low-noise amplifier for microelectrode probe, which integrated multimicroelectrode array for extracellular recording of neural activities and solid state circuits for the amplification of induced signals from the electrodes onto one substrate, was fabricated. In the amplifier, low-noise MOSFETs are used in the first stage, an interstage high-pass filter is incorporated to avoid saturation of the amplifier due to the polarization voltage of the electrode. In the second stage, an operational amplifier incorporating Bi-MOSFETs for the realization of high input impedance and large gain-bandwidth product is used. The gain of the fabricated amplifier is 56 dB for the frequency range between 2 Hz to 10 kHz, the noise voltage is 20µVpp; these satisfied design specifications.

The paper proposes and reports on pototyping a work bench system for novice Prolog programmers which consists of a visually-structured interactive tracer and a prototype-based programming support. The tracer actually is a simulated interpreter in Prolog. It is interpreted by a Prolog interpreter being embedded with facilities interfacing programs in Prolog and the objects programmed in C. It displays, by way of these objects, the past, current and future goals, highlights variable sharing and value substitution, and marks the current goals and backtrack choice points. It is at user's will to let the tracer show and hide subgoals as well as to let it backtrack when it failed, step back for redoing or terminate tracing. The programming support module first provides the programmer with structural prototype patterns and the roles of the constituent functions. We developed a support system for the 2 types of recursive definitions. After having selected the prototype, the user is requested to specify the data types and the names of variables to be put in the arguments, which propagate through the structure. The support module then offers a menu of primitive or user-registered constituent functions as may be useful in processing and/or obtaining user-specified types of data. Thirdly the system lets the user express his/her intention by sample input-output data instances in his/her task goals. It makes the values propagate through the structures thus motivating the user to design the constituent functions. At the goal recursion point, the user is allowed to creep into examining the definitions of the reduced versions of the instances, helping the user find the condition with which the recursion terminates. Finally the module assists the user to convert the structural descriptions into Prolog programs.