A new concept of changing inductance values has been proposed, where a part of meander inductor is short circuited to reduce effective line length. Microwave characteristics of the short-circuited meander inductors and the meander inductor without the short circuit have been designed and fabricated on resin circuit boards. The reduction of inductance values by 40% has been successfully realized for the microwave frequency range from 0.5 GHz to 5 GHz for both designed and measured results. Using the proposed structure, low pass filters having two different cut-off frequencies have been designed and tested. Measured cut-off frequency changed 3.0 GHz to 4.2 GHz.

The electromagnetic scattering of a plane wave by an inhomogeneous plane whose surface impedance changes locally on the plane is treated. A boundary-value problem is formulated to describe the scattering phenomenon, in which the boundary condition depends on the surface impedance of the plane. Application of the Fourier transform derives an integral equation, which is approximately solved by the method of least-squares. From the solution of the equation, the scattered field is obtained by the inverse Fourier transform. By the use of the incomplete Lipschitz-Hankel integral for the computation of the field, numerical examples are given and the scattering phenomenon is discussed.

We propose a new method to precisely detect pupil contours in face images. Pupil contour detection is necessary for various applications using face images. It is, however, difficult to detect pupils precisely because of their weak edges or lack of edges. The proposed method is based on minimizing the energy of pattern and edge. The basic idea of this method is that the energy, which consists of the pattern and the edge energy, has to be minimized. An efficient search method is also introduced to overcome the underlying problem of efficiency in energy minimization methods. "Guide patterns" are introduced for this purpose. Moreover, to detect pupils more precisely we use an ellipse model as pupil shape in this paper. Experimental results show the effectiveness of the proposed method.

There are two main types of digital watermark systems. In the first, users are given their own detection programs by which to verify the presence of watermark in data they have in their possession. In the second, users must request such verification from a detection center. The disadvantage of the first type is the possibility that a user might be able to analyze the detection program sufficiently to be able to obtain the secret data (secret key) used to embed the watermark. The disadvantage of the second is the possibility that a center might give dishonest results. In this paper, we propose a watermark detection scheme that can be used to overcome the disadvantages of both: it prevents users from obtaining secret key, and it prevents a center from reporting dishonest results. Our scheme is based on a previously proposed scheme which nearly achieved the same goals but, unfortunately, allowed users to receive watermark detection results for data specially created by them so as to reveal, through the results, secret information about how a center created its watermarks. To overcome this drawback, we have developed new scheme by which a center can prove its detection results to a user without revealing any other information. This scheme was developed by extending the work found in. Moreover we provide an option that prevents the center from encroaching on a user's privacy. The resulting watermark detection scheme is the first that, in addition to protecting secret keys of watermarks from user-tampering, is also able to prevent a center from reporting dishonest results. Although the proposed scheme is introduced first using the patch-work watermarking system, it is straightforward to extend it to a scheme that uses the correlation-based watermarking system, which yields a more robust watermark detection scheme.

Synchronous Gaussian code-division multiple access (CDMA) systems employing group-orthogonal signature waveforms are proposed and analyzed. All users in the system are divided into groups of users. The signature waveforms are constructed such that all the signature waveforms in one group are orthogonal to all the signature waveforms used in all other groups. This construction of signature waveforms ensures that there is no inter-group interference (i.e., among users in different groups), but at the expense of having intra-group interference (i.e., among users in the same group). However, by choosing a small size for each group, the intra-group interference can be effectively handled by a low-complexity, optimal (or suboptimal) multiuser detector. It is shown that a significant improvement in the system capacity can be achieved by the proposed technique over the conventional one that uses signature waveforms constructed from Welch-bound-equality (WBE) sequences. In particular, it is demonstrated that, while the conventional system's error performance is very sensitive to even small amount of overload, the proposed system with an appropriate design of signature waveforms can achieve a much higher overload (up to 300% as shown in the paper) with an excellent error performance.

This letter proposes a millimeter-wave band transformer to connect a standard waveguide to a very thin post-wall waveguide. The post-wall waveguide height is the same as a microstrip or coplanar line. A dielectric substrate with slits etched on both edges is inserted in the standard waveguide for matching. A 22 GHz transformer gives 3.6% bandwidth for a 0.5 mm-height post-wall waveguide. The effects of various mechanical misalignments upon the frequency characteristics of the reflection are also estimated by analysis and measurements.

We analytically investigate combinatorial effects of timer control and backoff algorithms on performance of bulk data transfer over two-state Markovian packet error channels. Numerical results for throughput, energy efficiency, and the probabilities of packet loss and loss of bulk data indicate that linear backoff algorithms outperform binary exponential ones as a whole when they are employed at the logical link sublayer with timer control.

In this paper, we propose OOK-CDMA system with optical hard-limiters (OHLs) using schemes of transmitting optical pulses with two-level intensities. The proposed system can be applied to both cases with single OHL and double OHLs. In the proposed system, a frame corresponding to a bit time is divided into two frames, where the low intensity pulses are transmitted in the weighted positions at the former frame, and the high ones are transmitted in the weighted positions at the latter frame. At the receiver side, in each weighted position of low intensity level, the ability of Multiple Access Interferences (MAIs) cancellation by OHL is equal to that of the conventional systems. However, in each weighted position of high intensity level, the OHL with the higher-level threshold value can easily eliminate MAIs with low intensity, while the MAIs are not eliminated in the conventional system. As a result, the ability of interference cancellation by OHL is significantly increased. When using single OHL in the proposed system, the optimum combinations of the values of low-level weights and low-level intensity ratio depend on the received laser power. This means that deploying dynamic control of the values of low-level weights and low-level intensity ratio is an imperative requirement in the proposed system with single OHL. On the other hand, when using double OHLs, the optimum combinations of the values of low-level weights and low-level intensity ratio are always constant. We analyze the performance of the proposed system and show its advantage in terms of bit error probability compared to the conventional system in both cases with single OHL and double OHLs. We also show that the proposed system with double OHLs is more effective and practical than the one with single OHL depending on the received laser power.

Group multicasting is a generalization of multicasting whereby every member of a group is allowed to multicast messages to other members that belongs to the same group. The group multicast routing problem (GMRP) is that of finding a set of multicast trees with bandwidth requirements, each rooted at a member of the group, for multicasting messages to other members of the group. An optimal solution to GMRP is a set of trees, one for each member of the group, that incurs the least overall cost. This problem is known to be NP-complete and hence heuristic algorithms are likely to be the only viable approach for computing near optimal solutions in practice. In this paper, we derive a lower bound on the cost of an optimal solution to GMRP by using Lagrangean Relaxation and Subgradient Optimization. This lower bound is used to evaluate the two existing heuristic algorithms in terms of their ability to find close-to-optimal solutions.

We present a new keystream generator (KSG) MUGI, which is a variant of PANAMA proposed at FSE '98. MUGI has a 128-bit secret key and a 128-bit initial vector as parameters and generates a 64-bit string per round. The design is particularly suited for efficient hardware implementations, but the software performance of MUGI is excellent as well. A speed optimized implementation in hardware achieves about 3 Gbps with 26 Kgates, which is several times faster than AES. On the other hand, the security of MUGI has been evaluated by analyzing the applicability of re-synchronization attacks, related-key attacks, and attacks that exploit the linear correlation of an output sequence. Our analysis confirms that MUGI is a secure KSG.

This paper presents a novel technique for reconstructing an outdoor sculpture from an uncalibrated image sequence acquired around it using a hand-held camera. The technique introduced here uses only the silhouettes of the sculpture for both motion estimation and model reconstruction, and no corner detection nor matching is necessary. This is very important as most sculptures are composed of smooth textureless surfaces, and hence their silhouettes are very often the only information available from their images. Besides, as opposed to previous works, the proposed technique does not require the camera motion to be perfectly circular (e.g., turntable sequence). It employs an image rectification step before the motion estimation step to obtain a rough estimate of the camera motion which is only approximately circular. A refinement process is then applied to obtain the true general motion of the camera. This allows the technique to handle large outdoor sculptures which cannot be rotated on a turntable, making it much more practical and flexible.

In mobile OFDM systems, sub-carriers orthogonality will be broken due to Doppler shift, and this results in inter-carrier interference (ICI). Many methods have been proposed to compensate for this, however, these methods won't be suitable for fast fading caused by high mobile speed. In this letter, we propose a novel sampling theorem based pilot symbol-aided technique which can not only estimate the channel fading envelope (CFE) accurately under high relative Doppler frequency (RDF) but also achieve lower BER than conventional methods. The validity of the proposed method is demonstrated by computer simulations.

Direct sequence code division multiple access (DS-CDMA) provides flexible data transmission in wide range of data rates by the use of orthogonal multicode multiplexing. In a multipath fading environment, the transmission performance of multicode DS-CDMA degrades as that of single code DS-CDMA does. Chip interleaving is known to improve the bit error rate (BER) performance of the single code transmission by altering the fading channel into severely time selective fading channel. However, this partially destroys orthogonality property among spreading codes and thus, significantly degrades the BER performance of multicode DS-CDMA. In this paper, we propose the joint use of chip interleaving and time-domain minimum mean square error combining (MMSEC) equalization to improve the multicode DS-CDMA transmission performance. It is confirmed by computer simulations that the joint use of chip interleaving and MMSEC equalization significantly improves the BER performance of multicode DS-CDMA and achieves better BER performance compared to the single code DS-CDMA using chip interleaving and maximal ratio combining (MRC).

A polarization switchable slot-coupled microstrip antenna using PIN diodes is proposed and studied. The microstrip feed line installed behind the ground plane is divided into two branches and each tip of the branches is connected to the ground plane through a PIN diode. One of the diodes is oriented from the tip to the ground plane and the other is oriented from the ground to the tip so that a slot in the ground can be selected to feed the patch by switching the dc bias between positive and negative. This selection contributes to switch the polarization between horizontal and vertical. In this paper, the authors investigate the polarization switching antenna theoretically and experimentally and confirmed sufficient differencce of antenna gain between horizontal and vertical polarization.

The side channel attack (SCA) is a serious attack on wearable devices that have scarce computational resources. Cryptographic algorithms on them should be efficient using small memory--we have to make efforts to optimize the trade-off between efficiency and memory. In this paper we present efficient SCA-resistant scalar multiplications based on window method. Moller proposed an SPA-resistant window method based on 2w-ary window method, which replaces w-consecutive zeros to 1 plus w-consecutive and it requires 2w points of table (or 2w-1 + 1 points if the signed 2w-ary is used). The most efficient window method with small memory is the width-w NAF, which requires 2w-2 points of table. In this paper we convert the width-w NAF to an SPA-resistant addition chain. Indeed we generate a scalar sequence with the fixed pattern, e.g. |00x|00x||00x|, where x is positive odd points < 2w. Thus the size of the table is 2w-1, which is optimal in the construction of the SPA-resistant chain based on width-w NAF. The table sizes of the proposed scheme are 6% to 50% smaller than those of Moller's scheme for w = 2,3,4,5, which are relevant choices in the sense of efficiency for 160-bit ECC.

This paper describes the design, fabrication, and measurement of a multiple U-shaped slot antenna for Hiper-LAN. The prototype consists of a U-shaped slot and two inverted U-shaped slot. To obtain sufficient bandwidth, a foam layer is inserted between the ground plane and substrate. A measured bandwidth of approximately 7.6% (VSWR 1.5) and gain of 2.9-5.3 dBi are obtained. The experimental far-field patterns are shown to be stable across the pass band, with the 3 dB beam width in azimuth and elevation at 50and 62, respectively.

The characteristics of HfO2 gate stacks, which consisted of the SiN layer deposited between the HfO2 and poly-Si gate electrode and the SiON interfacial layer were investigated. The SiN layer played important role to reduce the leakage current caused by the defect of the crystallized HfO2. The SiN layer was also effective to achieve the prevention of the interfacial reaction, the suppression of dopant penetration. Furthermore, that stack structure indicated excellent TDDB reliability fabricated by conventional high temperature processes.

The recent development of network technology has enabled us to access various information sources easily, and their integration has been studied intensively by the data engineering research community. Although technological advancement has made it possible to integrate existing heterogeneous information sources, we still have to deal with information sources of a new kind--dissemination-based information sources. They actively and autonomously deliver information from server sites to users. Integration of dissemination-based information sources is one of the popular research topics. We have been developing an information integration system in which we employ ECA rules to enable users to define new information delivery services integrating multiple existing dissemination-based information sources. However, it is not easy for users to directly specify ECA rules and to verify them. In this paper, we propose a scheme to specify new dissemination-based information delivery services using the framework of relational algebra. We discuss some important properties of the specification, and show how we can derive ECA rules to implement the services.

Discrete wavelet transform has been successfully used in many image processing applications. In this paper, we present an efficient VLSI architecture for 2-D 3-level lifting-based discrete wavelet transform using the (5, 3) filter. All three-level coefficients are computed interlacingly and periodically to achieve higher hardware utilization and better throughput. In comparison with other VLSI architectures, our architecture requires less size of storage and faster computation speed.

This letter presents a novel two-dimensional (2-D) defected ground array (DGA) for planar circuits, which has horizontal and vertical periodicities of defect structure. The defect unit cell of DGA is composed of a Sierpinski carpet structure to improve the effective inductance. Measurements show that the proposed DGA provides steeper cutoff characteristics, lower cutoff frequency, and higher slow-wave factors than the conventional periodic defected ground structure in the same occupied surface.