This letter proposes a robust biometric authenticated key agreement (BAKA) protocol for a secure token to provide strong security and minimize the computation cost of each participant. Compared with other related protocols, the proposed BAKA protocol not only is secure against well-known cryptographical attacks but also provides various functionality and performance requirements.

10G-EPON systems have attracted a great deal of attention as a way of exceeding to realize over 10 Gb/s for optical subscriber networking. Rapid burst-mode transmitting/receiving techniques are the key technologies enabling the burst-mode upstream transmission of 10G-EPON systems. In this paper, we have developed a OLT burst-mode 3R receiver incorporating a burst-mode AGC optical receiver and an 82.5 GS/s over-sampling burst-mode CDR and a ONU burst-mode transmitter with high launch power DFB-LD of 1.27 µm wavelength to fully compliant with IEEE802.3av 10G-EPON PR30 standards. The transmitting characteristics of a fast LD turn-on/off time of less than 6ns and a high launch power of more than +8.0 dBm, and the receiving characteristics of receiver sensitivity of -30.1 dBm and the upstream power budget of 38.1 dB are successfully achieved.

The purpose of this paper is to propose an efficient and effective design scheme to implement compact, high-performance wideband bandpass filters based on a novel compound three-line unit consisting of a stub-loaded short-circuited parallel-coupled three-line structure and two lead lines. Firstly, a simulative investigation is conducted on the transmission characteristics of the proposed coupling unit. The results show that the bandwidth of such structure can be predicted by a symmetric parallel-coupled short-circuited three-line unit, whereas the transmission zeros by a three-section stub composed of the loaded stub, one of the parallel-coupled three lines and the lead line. Accordingly, given specifications, a pseudo-elliptical filter can be designed in an novel three-coupled-line based two-step design scheme: 1. after the derivation of the new closed-form synthesis formulae, a Chebyshev ultra-wideband (UWB) filter is synthesized on a desired passband using symmetric three-line coupling units. 2. By designing the stubs and choosing the proper lengths of the lead lines, multiple transmission zeros are then introduced to improve the skirt and stopband characteristics, whereas the equiripple characteristics are kept in passband. As an example, a UWB bandpass filter covering the Japan's lower UWB band (BW: 3.1-4.8 GHz, FBW: 43%) is designed to describe the proposed design procedure. The measured filtering characteristics agree very well with the theoretical predictions, which validate the effectiveness of the proposed new coupling structure and corresponding filter design technique. In addition, the designed filters exhibit good characteristics, such as steep skirt selectivity, very wide stopbands, a compact size compared with the filter based on short-circuited three-line structure, etc.

In this paper, a microstrip lowpass filter using hairpin structure and Chip-Capacitor is proposed. Firstly, the LPF with one hairpin element is briefly designed and optimized with LC prototype structure using circuit simulator. With the capacitor loaded the proposed LPF illustrates the sharp attenuation performance near the cut-off frequency and the wideband rejection characteristics. Then, in order to improve the stopband attenuation the three-hairpin LPF is studied. By optimazing its design the attenuation is improved by 32 dB.

A new type of the wide-band BPF made up of an inter-digital resonator and parallel-coupled lines was proposed. The bandwidth of the inter-digital resonator becomes wider by increasing the number of fingers. The design of the parallel-coupled line was performed by optimazing the structural parameters so that the bandwidth is the same as that of the inter-digital resonator. The measured results of the combination of above elements for the BPF agreed well with the simulated ones such that the insertion loss is less than 0.67 dB and that the sharp skirt characteristics are realized by attenuation poles near the edges of the passband.

This paper deals with the influence of metal cover planes close to SMD filter structures. The low-pass structures are used for EMC purpose and work in a frequency range of 100 kHz to 4 GHz. It will be shown by both measurement and simulation that a close cover plane changes the filter behavior significantly in dependency of the filter component used. For low and high impedance filter structures different influences are obtained; a parameter study was carried out in order to derive design rules.

In this paper, a resonator based on composite right/left handed transmission line concept is discussed. This resonator excites --1st order resonance mode. We start with half-wave resonators consisting of two unit cells of a composite right/left handed transmission line. From the simulated field distributions, the center of these half-wave resonators can be short-circuited to obtain a quarter-wave resonator in the --1st mode. Susceptance slope parameters are calculated for the resonator. Then this resonator is applied for a 2-pole filter made by LTCC, which can be designed with standard filter design theory owing to the slope parameter. The dimension of the experimental filter implemented by LTCC is 2.5 mm by 1.35 mm by 0.52 mm. The insertion loss is 1.80 dB at the 2.4 GHz band. Good agreement between measured and computed results is obtained.

A low-voltage operational capability near 1 V along with low noise and distortion characteristics have been realized in a passive sigma-delta modulator. To achieve low-voltage operation, the dc voltage in signal paths in the switched-capacitor-filter section was set to be 0.2 V so that sufficient gate-to-source voltages were obtained for metal-oxide-semiconductor (MOS) switches in signal paths without using a gate-voltage boosting technique. In addition, the input switch that connects the input signal from the outside to the inside of an integrated circuit chip was replaced by a passive resistor to eliminate a floating switch, and gain coefficients in the feedback and input paths were modified so that the bias voltage of the digital-to-analog converter could be set to VDD and 0 V to easily activate MOS switches. As the signal swing becomes small under low-voltage operational circumstances, correlated double sampling was used to suppress the offset voltage and the 1/f noise that appeared at the input of a comparator. The modulator was fabricated using a standard CMOS 0.18-µm process, and the measured results show that the modulator realized 77 dB of dynamic range for 40 kHz of signal bandwidth with a 40 MHz sampling rate while dissipating 2 mW from a 1.1 V supply voltage.

Secure channels can be realized by an authenticated key exchange (AKE) protocol that generates authenticated session keys between the involving parties. In, Shin et al., proposed a new kind of AKE (RSA-AKE) protocol whose goal is to provide high efficiency and security against leakage of stored secrets as much as possible. Let us consider more powerful attacks where an adversary completely controls the communications and the stored secrets (the latter is denoted by "replacement" attacks). In this paper, we first show that the RSA-AKE protocol is no longer secure against such an adversary. The main contributions of this paper are as follows: (1) we propose an RSA-based leakage-resilient AKE (RSA-AKE2) protocol that is secure against active attacks as well as replacement attacks; (2) we prove that the RSA-AKE2 protocol is secure against replacement attacks based on the number theory results; (3) we show that it is provably secure in the random oracle model, by showing the reduction to the RSA one-wayness, under an extended model that covers active attacks and replacement attacks; (4) in terms of efficiency, the RSA-AKE2 protocol is comparable to in the sense that the client needs to compute only one modular multiplication with pre-computation; and (5) we also discuss about extensions of the RSA-AKE2 protocol for several security properties (i.e., synchronization of stored secrets, privacy of client and solution to server compromise-impersonation attacks).

The design of microstrip bandpass filters using stepped-impedance resonators (SIRs) is examined. The passband center frequency for the WCDMA-FDD (uplink band) Japanese cellular system is 1950 MHz with a 60-MHz bandwidth. The SIR physical characteristic can be designed using a SIR characteristic chart based on second harmonic suppression. In our filter design, passband design charts were obtained through the design procedure. Tchebycheff and maximally flat bandpass filters of any bandwidth and any number of steps can be designed using these passband design charts. In addition, sharp skirt characteristics in the passband can be realized by having two transmission zeros at both adjacent frequency bands by using open-ended quarter-wavelength stubs at input and output ports. A new even-mode harmonics suppression technique is proposed to enable a wide rejection band having a high suppression level. The unloaded quality factor of the resonator used in the proposed filters is greater than 240.

In this paper, an ultra low power analog front-end for EPCglobal Class 1 Generation 2 RFID tag is presented. The proposed RFID tag removes the need for high frequency clock and counters used in conventional tags, which are the most power hungry blocks. The proposed clock-free decoder employs an analog integrator with an adaptive current source that provides a uniform decoding margin regardless of the data rate and a link frequency extractor based on a relaxation oscillator that generates frequency used for backscattering. A dual supply voltage scheme is also employed to increase the power efficiency of the tag. In order to improve the tolerance of the proposed circuit to environmental variations, a self-calibration circuit is proposed. The proposed RFID analog front-end circuit is designed and simulated in 0.25 µm CMOS, which shows that the power consumption is reduced by an order magnitude compared to the conventional RFID tags, without losing immunity to environmental variations.

In this paper, we utilize low temperature co-fired ceramic technology (LTCC) to realize a modified short-circuited stub bandpass filter suitable for ultra-wideband (UWB) applications. By modifying the conventional short-circuited stub bandpass filter structure with stubs and connecting lines of lower characteristic impedances, the number of stubs has been reduced from 5 to 2 on a high dielectric constant substrate (∈ r = 40). A wireless local area network (WLAN) stopband in the frequency range of 5.15 to 5.825 GHz has been inserted into the filter characteristic using three short-circuited coupled lines. The filter is fabricated and measurement results show that it has an insertion loss less than 1.0 dB and return loss better than 10 dB in the pass bands. A bandwidth ratio of 109.49% has been achieved. Measurement results agree well with simulation results. The dimensions of the filter are 480.57 mm3.

This paper presents an autonomous navigation system for a mobile robot using randomly distributed passive RFID tags. In the case of randomly distributed RFID tags, it is difficult to provide the precise location of the robot especially in the area of sparse RFID tag distribution. This, combined with the wide turning radius of the robot, can cause the robot to enter a zigzag exploration path and miss the goal. In RFID-based navigation, the key is to reduce both the number of RFID tags and the localization error for practical use in a large space. To cope with these, we utilized the Read time, which measures the reading time of each RFID tag. With this, we could estimate accurately the localization and orientation without using any external sensors or increasing the RFID tags. The average estimation errors of 7.8 cm in localization and 11 degrees in orientation were achieved with 102 RFID tags in the area of 4.2 m by 6.2 m. Our proposed method is verified with the path trajectories produced during navigation compared with conventional approaches.

We demonstrated an automated passive-transmission-line routing tool for single-flux-quantum (SFQ) circuits. The tool is based on the A* algorithm, which is widely used in CMOS LSI design, and tuned for microstrip/strip lines formed in the SRL 4-Nb layer structure. In large-scale SFQ circuits with 10000-20000 Josephson junctions, such as microprocessors, 80-90% of the wires can be automatically routed in about ten minutes. We verified correct operation above 40 GHz for an automatically routed 44 switch circuit from on-chip high-speed tests. The resulting circuit size and operating frequency were comparable to those of a manually designed result. We believe that the tool is useful for large-scale SFQ circuit design using conventional fabrication processes.

This research paper points out that the gateway-oriented password-based authenticated key exchange protocol recently developed by Shim (S-GPAKE) was inefficiently and incorrectly designed to overcome an undetectable on-line password guessing attack. To resolve the computation efficiency and security problems, an optimized GPAKE protocol (O-GPAKE), which was not only secure against various security attacks, but also had considerably lower computational cost and provided mutual authentication unlike previous related protocols including the S-GPAKE protocol was proposed.

Output voltage regulation problem of DC-DC boost power converters is studied based on an averaged model with a practical inductor. This paper exploits the effect of inductor's parasitic resistance on the performance of an existing parallel-damped (PD) passivity-based controller (PBC) under load variations. As an attempt to apply the passivity-based framework to the converter with parasitic resistance we have combined a new proportional-integral (PI) controller with the PBC. Simulation results show that the combined (PBC and PI) dynamic output feedback controller successfully achieves the performance improvement under reference step changes and load variations.

A boosted bit line program scheme is proposed for low operating voltage in the multi-level-cell (MLC) NAND flash memory. Our BL to BL boosting scheme, which uses the BL coupling capacitance, is applied to achieve a higher channel potential than is possible with Vcc, so that the Vpass window margin is improved by up to 59% in 40 nm MLC NAND flash memory with 2.7 V Vcc. In the case of 1.8 V Vcc, the margin of the proposed scheme is 12% higher than one of the conventional schemes at 2.7 V Vcc.

This paper proposes a power saving mechanism with variable sleep period to reduce the power consumed by optical network units (ONUs) in passive optical network (PON) systems. In the PON systems based on time division multiplexing (TDM), sleep and periodic wake-up (SPW) control is an effective ONU power saving technique. However, the effectiveness of SPW control is fully realized only if the sleep period changes in accordance with the traffic conditions. This paper proposes an SPW control mechanism with variable sleep period. The proposed mechanism sets the sleep period according to traffic conditions, which greatly improves the power saving effect. In addition, the protocols needed between an optical line terminal (OLT) and ONUs are described on the assumption that the proposed mechanism is applied to 10 Gigabit (10G) class PON systems, i.e. IEEE 802.3av 10G-EPON and FSAN/ITU-T 10G-PON systems. The validity of the proposed mechanism is confirmed by numerical simulations.

A band-pass bilateral filter is an improved variant of a bilateral filter that does not have low-pass characteristics but has band-pass characteristics. Unfortunately, its computation time is relatively large since all pixels are subjected to Gaussian calculation. To solve this problem, we pay attention to a nonlinear filter called ε-filter and propose an advanced ε-filter labeled band-pass ε-filter. As ε-filter has low-pass characteristics due to spatial filtering, it does not enhance the image contrast. On the other hand, band-pass ε-filter does not have low-pass characteristics but has band-pass characteristics to enhance the image contrast around edges unlike ε-filter. The filter works not only as a noise reduction filter but also as an edge detection filter depending on the filter setting. Due to its simple design, the calculation cost is relatively small compared to the band-pass bilateral filter. To show the effectiveness of the proposed method, we report the results of some comparison experiments on the filter characteristics and computational cost.

We present our proposed designs of optical access architecture based on WDM technology toward new-generation networks for two types of topologies: Single-star (SS) and passive-double-star (PDS). We adopt the concept of WDM-direct which links multiple wavelengths to each optical network unit (ONU). Our proposed architecture based on WDM-direct can achieve more than 10 Gbps access per ONU. Moreover, our architecture can provide not only conventional bandwidth-shared services but also bandwidth-guaranteed services requiring more than 10 Gbps bandwidth by establishing end-to-end lightpaths directly to each ONU, and thus meet high requirements of QoS in new-generation networks. Firstly, we show our proposed designs of SS-type architecture, and experimentally demonstrate the system. We confirm that the optical line terminal (OLT) successfully switches between packet/lightpath data transmissions for each ONU. In addition, we measure and evaluate optical power loss in upstream/downstream transmissions between the OLT and ONUs. Secondly, we show our proposed designs of PDS-type architecture, and theoretically analyze and evaluate the bit-rate capacity of the system.