This paper proposes a block-permutation-based encryption (BPBE) scheme for the encryption-then-compression (ETC) system that enhances the color scrambling. A BPBE image can be obtained through four processes, positional scrambling, block rotation/flip, negative-positive transformation, and color component shuffling, after dividing the original image into multiple blocks. The proposed scheme scrambles the R, G, and B components independently in positional scrambling, block rotation/flip, and negative-positive transformation, by assigning different keys to each color component. The conventional scheme considers the compression efficiency using JPEG and JPEG 2000, which need a color conversion before the compression process by default. Therefore, the conventional scheme scrambles the color components identically in each process. In contrast, the proposed scheme takes into account the RGB-based compression, such as JPEG-LS, and thus can increase the extent of the scrambling. The resilience against jigsaw puzzle solver (JPS) can consequently be increased owing to the wider color distribution of the BPBE image. Additionally, the key space for resilience against brute-force attacks has also been expanded exponentially. Furthermore, the proposed scheme can maintain the JPEG-LS compression efficiency compared to the conventional scheme. We confirm the effectiveness of the proposed scheme by experiments and analyses.

Encryption-then-Compression (EtC) systems have been considered for the user-controllable privacy protection of social media like Twitter. The aim of this paper is to evaluate the security of block scrambling-based encryption schemes, which have been proposed to construct EtC systems. Even though this scheme has enough key spaces against brute-force attacks, each block in encrypted images has almost the same correlation as that of original images. Therefore, it is required to consider the security from different viewpoints from number theory-based encryption methods with provable security such as RSA and AES. In this paper, we evaluate the security of encrypted images including JPEG distortion by using automatic jigsaw puzzle solvers.

The aim of this paper is to apply automatic jigsaw puzzle solvers, which are methods of assembling jigsaw puzzles, to the field of information security. Encryption-then-Compression (EtC) systems have been considered for the user-controllable privacy protection of digital images in social network services. Block scrambling-based encryption schemes, which have been proposed to construct EtC systems, have enough key spaces for protecting brute-force attacks. However, each block in encrypted images has almost the same correlation as that of original images. Therefore, it is required to consider the security from different viewpoints from number theory-based encryption methods with provable security such as RSA and AES. In this paper, existing jigsaw puzzle solvers, which aim to assemble puzzles including only scrambled and rotated pieces, are first reviewed in terms of attacking strategies on encrypted images. Then, an extended jigsaw puzzle solver for block scrambling-based encryption scheme is proposed to solve encrypted images including inverted, negative-positive transformed and color component shuffled blocks in addition to scrambled and rotated ones. In the experiments, the jigsaw puzzle solvers are applied to encrypted images to consider the security conditions of the encryption schemes.

Among several optical devices in integrated optics, the fundamental characteristics of collinear optical switching devices have been studied about optical dielectric waveguides. Conventional waveguide-type acousto-optic (A-O) devices use collinear and longitudinal interactions with mode coupling based on the Bragg condition between optical waves and surface acoustic waves (SAW). Collinear A-O devices of the waveguide-type show sufficient performance for wavelength-selective switching with narrow bandwidths. However, in these collinear A-O devices, interaction time is several microseconds for 10 mm waveguide device length. In A-O devices of optical waveguides using transverse A-O interaction, where SAW propagates transversely to optical wave propagation direction, SAW propagation lengths needed for complete A-O interaction may become 10 µm and interaction time may be several nanoseconds. In this paper, fundamental characteristics of the transverse A-O interaction are studied as an electromagnetic boundary value problem. Refractive indices in optical waveguides induced by A-O effects with SAW are shown by sine functions. Wave field characteristics in periodic structures for transverse directions are analyzed by analytic method of Hill's equations for transverse spectral functions. Electromagnetic fields in regions with periodic structures are discussed by the Mathieu functions and the perturbation method. Dispersion characteristics of A-O eigen modes are studied for wavelengths of optical waves and SAW, with A-O coefficients.

In this letter, we prove that the Kurosawa-Desmedt (KD) scheme [10], which belongs to the hybrid framework, is KDM-CCA secure w.r.t. an ensemble proposed by Qin et al. in [12] under the decisional Diffie-Hellman assumption. Since our proof does not rely on the random oracle model, we partially answer the question presented by Davies and Stam in [7], where they hope to achieve the KDM-CCA security for hybrid encryption scheme in the standard model (i.e. not random oracle model). Moreover, our result may also make sense in practice since KD-scheme is (almost) the most efficient CCA secure scheme.

We present a multiband LTE SAW-less CMOS transmitter with source-follower-driven passive mixers, envelope-tracked RF-programmable gain amplifiers (RF-PGAs), and Marchand Baluns. A driver stage for passive mixers is realized by a source follower, which enables a quadrature modulator (QMOD) to achieve low noise performance at a 1.2 V supply and contributes to a small-area and low-power transmitter. An envelope-tracking technique is adopted to improve the linearity of RF-PGAs and obtain a better Evolved Universal Terrestrial Radio Access Adjacent Channel Leakage power Ratio (E-UTRA ACLR). The Marchand balun covers more frequency bands than a transformer and is more suitable for multiband operation. The proposed transmitter, which also includes digital-to-analog converters and a phase-locked loop, is implemented in a 65-nm CMOS process. The implemented transmitter achieves E-UTRA ACLR of less than -42 dBc and RX-band noise of less than -158 dBc/Hz in the frequency range of 700 MHz–2.6 GHz. These performances are good enough for multiband LTE and SAW-less operation.

With the aim to improve the effectiveness of SAWSDL service discovery, this paper proposes a novel discovery method for SAWSDL services, which is based on the matchmaking of so-called fine-grained data semantics that is defined via sets of atomic elements with built-in data types. The fine-grained data semantics can be obtained by a transformation algorithm that decomposes parameters at message level into a set of atomic elements, considering the characteristics of SAWSDL service structure and semantic annotations. Then, a matchmaking algorithm is proposed for the matching of fine-grained data semantics, which avoids the complex and expensive structural matching at the message level. The fine-grained data semantics is transparent to the specific data structure of message-level parameters, therefore, it can help to match successfully similar Web services with different data structures of parameters. Moreover, a comprehensive measure is proposed by considering together several important components of SAWSDL service descriptions at the same time. Finally, this method is evaluated on SAWSDL service discovery test collection SAWSDL-TC2 and compared with other SAWSDL matchmakers. The experimental results show that our method can improve the effectiveness of SAWSDL service discovery with low average query response time. The results imply that fine-grained parameters fit to represent the data semantics of SAWSDL services, especially when data structures of parameters are not important for semantics.

Sawtooth wave generator which has very steep down-slope and little amplitude and oscillation frequency error, is proposed. Because the down-slope is achieved by switching two triangular waves exclusively, the shape of the down-slope becomes very steep. The proposed method realizes not only the steep down-slope but also less amplitude error and less oscillation frequency error compared with conventional method. Spectre simulations are performed by using 0.18 µm CMOS process and transient simulation results show the proposed circuit has quite less amplitude and frequency error for 5 MHz oscillation compared with the conventional method.

Three-dimensional visualization using jigsaw-puzzle-like glyphs, or shapes, is proposed as a means of representing grammatical constraints in programming. The proposed visualization uses 3D glyphs such as convex, concave, and wireframe shapes. A semantic constraint, such as a type constraint in an assignment, is represented by an inclusive match between 3D glyphs. An application of the proposed visualization method to a subset of the Java programming language is demonstrated. An experimental evaluation showed that the 3D glyphs are easier to learn and enable users to more quickly understand their relationships than 2D glyphs and 1D symbol sequences.

Recent advancements in the ubiquitous sensor network field have brought considerable feasibility to the realization of a ubiquitous society. A ubiquitous sensor network will enable the cooperative gathering of environmental information or the detection of special events through a large number of spatially distributed sensor nodes. Thus far, radio frequency identification (RFID) as an application for realizing the ubiquitous environment has mainly been developed for public and industrial systems. To this end, the most existing applications have demanded low-end antennas. In recent years, interests of ubiquitous sensor network have been broadened to medical body area networks (BAN), wireless personal area networks (WPAN), along with ubiquitous smart worlds. This increasing attention toward in ubiquitous sensor network has great implications for antennas. The design of functional antennas has received much attention because they can provide various kinds of properties and operation modes. These high-end antennas have some functions besides radiation. Furthermore, smart sensor nodes equipped with cooperated high-end antennas would allow them to respond adaptively to environmental events. Therefore, some design approaches of functional antennas with sensing and reconfigurability as high-end solution for smart sensor node, as well as low-end antennas for mobile RFID (mRFID) and SAW transponder are presented in this paper.

An ultra low power CMOS SAW oscillator in the 300-MHz-band that operates on a sub-1 V supply voltage and at sub-1 mW power consumption has been developed. The SAW oscillator is fabricated in a 0.35-µm fully depleted SOI (FD-SOI) process with low voltage operation capability. The SAW oscillator is configured as a type of Colpitts oscillator but consists of 3 cascaded amplifiers instead of a single amplifier. Although the circuit configuration is quite similar to the conventional Colpitts oscillator, this proposed configuration generates an excessively high negative resistance that even exceeds the theoretical limit of the conventional one.

A new design concept for a common-mode signal suppression circuit for a balanced-type filter has been investigated. The degradation mechanism of the balance characteristics was studied. The degradation is caused by the common-mode signals combined with the differential-mode signals in the balanced terminals. The concept employed is the reduction of the common-mode signal using a common-mode signal suppression circuit, connected to the balanced terminals. A serial resonance circuit is formed, in which the common-mode signals are shorted to ground. The circuit was applied to the balanced-type Surface Acoustic Wave (SAW) filter. The improvement in balance characteristics, without increasing in the insertion loss, was confirmed by experiments for Global System Mobile (GSM) applications.

We have proposed and implemented a spread spectrum (SS) wireless switch using 2.4 GHz front-end AlN/Al2O3 surface acoustic wave (SAW) matched filter (MF). Since the SAW MF has radio frequency (RF) front-end operation, RF components are not needed in the received circuit. High impedance in the peripheral circuit using passive devices has been employed for low current consumption. The SS wireless switches have been designed with the power consumption of less than 100 µW by using the SAW MF. It is confirmed that implemented SS wireless switch has a long battery life of 10 years and communication range of 30 m.

We have proposed the packet SS-CDMA scheme for downlink of SS-CDMA flexible wireless cellular network. Transmission packet is framed with synchronization block with 11 chip Barker code and information block with orthogonal spreading code. The chip synchronization is carried out using short code surface acoustic wave (SAW) matched filter. The code de-spreading is carried out using in-line de-spreader. Multi-channel downlink of 63 channels can be designed using orthogonal m-sequence. Simulation results show more than 15 channels without degradation from theoretical value can be used under multi-path environment. The packet SS-CDMA modem has been implemented using a 2.4 GHz front-end SAW matched filter. Degradation of Eb/N0 of less than 0.5 dB is experimentally achieved with four-channel multiplex.

This paper describes a jitter suppression technique for a clock multiplier IC that uses a phase-locked loop (PLL). It is shown that the jitter cutoff frequency of the jitter transfer function can be greatly improved by adding a surface acoustic wave (SAW) filter whose center frequency equals the input frequency. The jitter transfer function is mainly determined by the characteristics of the SAW filter. Therefore, the clock multiplier IC can be set at a high loop gain to minimize the jitter generation without increasing the jitter cutoff frequency. The use of a clock multiplier IC that was fabricated with Si bipolar technology and a SAW filter with the center frequency of 155.52 MHz and a quality (Q) factor of 1500 results in a very low jitter generation of 3.5 mUI rms and an extremely low jitter cutoff frequency of about 50 kHz when the clock multiplier converts a clock frequency of 155.52 MHz into a 2.48832-GHz signal.

We have developed a half-duplex spread spectrum-direct sequence (SS-DS) 2. 4 GHz band transceiver (T/R) unit having a smaller size and lower power consumption. A highly efficient elastic SAW convolver with chirp interdigital transducers (IDTs) has been used in the correlation circuit of receiver unit. The code shift keying (CSK) modulation is used in the T/R unit. The size of T/R unit is 90 50 11 mm and the weight is 75 grams. The power consumption of T/R unit is 1. 4 watts. We found that the bit error rate (BER) was less than 10-6 over the range of 0-150 m outdoors and 0-80 m indoors without a digital error detection and correction method. In this case, the data rate was 102 kbps and the transmit RF power was 2. 5 mW/MHz. The electrical characteristics, anti-interference and anti-multipath fading were also evaluated.

A wireless communications system with a transmission rate of 10 Mbit/s using Japanese ISM band (2471-2497 MHz) is presented. This system employs a novel spread spectrum multiple access method named "CFO-SS (Carrier Frequency Offset-Spread Spectrum)" method. In the CFO-SS system, a single PN code is commonly assigned to all the multiple carriers, and the frequency offset between the carriers is determined by the information symbol rate, which is small as compared with the spread bandwidth of the signal. Bit error rate performance of the proposed CFO-SS system under multipath environments is investigated by computer simulation, and the performance of the CFO-SS method is confirmed for wireless LAN systems using the 2.4 GHz ISM band.

A 2.4 GHz band direct sequence (DS) spread spectrum (SS) radio frequency modem with a wide bandwidth of 26 MHz in half-duplex system has been newly developed using the small size (832 mm) and highly-efficient (-57 dBm) elastic type of surface acoustic wave (SAW) convolver. The size of SS modem is 905011 mm and the weight is 75 g. The power consumption of SS modem is 1.5 W and data rate is 206 kbps with 63 chips of PN code. Electrical characteristics measurements were made to evaluate the SS modem performance.

Recently, Yagisawa proposed a public key cryptosystem which is very similar to the modified Lu-Lee cryptosystem. The differences are the set of messages and the decryption. On the other hand, Brickell and Odlyzko showed that the modified Lu-Lee cryptosystem is completely broken in polynomial time. This paper shows that Yagisawa cryptosystem is completely broken in the same way.

Taking a 1.5-GHz SAW antenna duplexer for PDC, we have developed a new configuration for the transmitter final stage filter and a new weighting technique for the receiver top filter. These transmitter and receiver filters provide insertion losses as low as 0.8 and 1.6 dB, respectively. Combining the filters, we have developed a miniature antenna duplexer of which size is 1.40.60.2 cm3 , several-time smaller than that of a conventional dielectric-filter duplexer. It also ensures sufficient power-handing capabilities.