Practical image restoration filters usually include a parameter that controls regularizability, trade-off between fidelity of a restored image and smoothness of it, and so on. Many criteria for choosing such a parameter have been proposed. However, the relation between these criteria and the squared error of a restored image, which is usually used to evaluate the restoration performance, has not been theoretically substantiated. Sugiyama and Ogawa proposed the subspace information criterion (SIC) for model selection of supervised learning problems and showed that the SIC is an unbiased estimator of the expected squared error between the unknown model function and an estimated one. They also applied it to restoration of images. However, we need an unbiased estimator of the unknown original image to construct the criterion, so it can not be used for general situations. In this paper, we present a modified version of the SIC as a new criterion for choosing a parameter of image restoration filters. Some numerical examples are also shown to verify the efficacy of the proposed criterion.

In positioning systems NLOS (Non-Line of Sight) errors always cause remarkable positive bias and directly increase range measurement errors. In this paper, a new method is proposed to calibrate NLOS errors in positioning systems by using the relationship between mean excess delay and delay spread measured at a mobile station. The computer simulations showed that the proposed calibration technique effectively reduces the positioning error caused by urban NLOS environment.

M-convex functions have various desirable properties as convexity in discrete optimization. We can find a global minimum of an M-convex function by a greedy algorithm, i.e., so-called descent algorithms work for the minimization. In this paper, we apply a scaling technique to a greedy algorithm and propose an efficient algorithm for the minimization of an M-convex function. Computational results are also reported.

A uniform raised-salicide technology has been investigated using both uniform selective-epitaxial-growth (SEG) silicon and salicide films, to reduce a junction leakage current of shallow source/drain (S/D) regions for high-performance CMOS devices. The uniform SEG-Si film without pits is formed by using a wet process, which is a carbon-free oxide removal only using a dilute hydrofluoric acid (DHF) dipping, prior to the Si-SEG process. After a titanium-salicide formation using a conventional two-step salicide process, this uniform SEG-Si film achieves good S/D junction characteristics. The uniform titanium-salicide film without bowing into a silicon is formed by a smaller Ti/SEG-Si thickness ratio, which results in a low sheet resistance of 5 Ω/sq. without a narrow-line effect. Furthermore, the drive current is maximized by this raised-salicide film using a Ti/SEG-Si thickness ratio of 1.0.

In this paper, we propose a new approach to the adaptive MLSE receiver, which is based on the delay estimation of the paths in the fading channel. The path delays are estimated by using the known training sequence, and based on this estimation the proposed MLSE tracks not the T-spaced equivalent channel but the variations of each path in the frequency-selective channel directly. It will be shown through computer simulations that the proposed MLSE can improve the performance of the conventional MLSE receivers, when the number of paths is small.

We propose a subchannel power control scheme in the OFDM system, which transmits data with a variable power level for each subchannel based on the received SNR. The OFDM system, employing the D-QPSK modulation and the proposed subchannel power control with a grouping coefficient equal to 3, gives about 2.3 dB gain in Eb/N0 comparing with the conventional OFDM system, under the two-ray multipath channel with the mean value of the second-ray's attenuation coefficient equal to 0.25, for the required BER equal to 10-5.

Multicast is an efficient way to send messages to a group of members. It is becoming the basis for a number of applications, such as teleconferencing, news groups, and on-line games. Security is one of the main issues in realizing multicast communications. A working group within IETF dedicated to multicast security has been formed and RFCs and working drafts concerning multicast security are proposed. This letter analyzes the security of a scheme proposed in [1] for securely establishing a shared, secret key in a large, dynamic group. We show that it fails to provide forward and backward security.

In this paper, we propose and analytically evaluate the use of punctured convolutional codes for recovering packets lost in multicast transmission. An independent erasure channel is assumed for packets transmission over a star topology. The analysis provides a method for determining the recoverability and the post-reconstruction receiving rate for a given convolutional code. We theoretically evaluate the effectiveness of the proposed approach taking into account two different parameters: the number of transmissions per packet and the number of packets needed to be sent to guarantee the reception of data. Finally, we compare the proposed approach with the scheme when parity packets are generated based on Reed-Solomon codes.

A lithium-ion (Li-ion) battery protection IC with an average current of 0.99 µA (at a battery voltage of 3.6 V) and a standby current (after detecting over-discharge) less than 0.01 µA is presented. This low power performance is achieved via a power-on duty-cycle technique. The protection circuit samples the voltage of the battery periodically and powers down during the rest of time. This Li-ion battery protector provides over-charge, over-discharge, excess-current and short circuits protection. This protection IC was implemented in a 0.6-µm CMOS technology and the active area is 880 µm 780 µm.

In this letter, we propose high-speed binary to residue converters for moduli 2n, 2n 1 without using look-up table. For integration of residue arithmetic circuit using a signed-digit (SD) number representation with ordinary binary system, the proposed circuits carry out the efficient conversion. Using SD adders instead of ordinary adders that are used in conventional binary to residue converter, the high-speed conversion without the carry propagation can be achieved. Thus, the proposed converter is independent of the size of modulus and can speed up the binary to residue conversion. On the simulation, the conversion delay times are 1.78 ns for modulus 210-1 and 1.73 ns for modulus 210+1 under the condition of 0.6 µm CMOS technology, respectively. The active area of the proposed converter for moduli 210 1 is 335 µm325 µm.

A method for estimating propagation characteristics is described that uses the characteristics of pilot-data-inserted orthogonal frequency division multiplexing (OFDM) signal and is suitable for high-mobility OFDM transmission scheme. Several pilot data are inserted periodically along the frequency axis before the inverse fast Fourier transformation (IFFT) process in the transmitter. At the receiver, the received OFDM signal is correlated with a prepared distinctive OFDM signal in which several pilot data are inserted in the same positions as in the transmitted OFDM symbols and zeros are inserted in the other positions. The propagation characteristics can be estimated precisely and used to cancel any interference caused by delayed waves. Computer simulation shows that this method can estimate the propagation characteristics, which can then be used to cancel the interference caused by delayed waves before the FFT at the receiver under fast multipath fading conditions.

Precise interconnect analysis is strongly required for giga-scale integration the operation frequency of which is excess 10 GHz. In this study, detailed and accurate analyses of a coaxial interconnect and an actual rectangular interconnect have been performed by the direct evaluation of Maxwell's equations and the finite element method, respectively. It has been revealed that there are two propagation modes for LSI interconnects: skin depth limited propagation mode and interconnect induced slow wave mode. In a miniaturized interconnect, the propagation mode is the interconnect induced slow wave mode; therefore, we cannot obtain the light-speed propagation due to such an interconnect-induced effect. In order to overcome this speed limitation or to improve signal integrity, it is essential to introduce a short interconnect for a miniaturized structure, and a much larger interconnect than the skin depth. We propose a gas-isolated interconnect as a candidate for an ultimately low-k structure in order to increase the signal-propagation speed. By the introduction of such structures, the performance of miniaturized devices in the deep submicron region will be effectively enhanced.

For ubiquitous computing and communication, a mobile node needs to change upon movements its network- and link-layer points of attachment to the Internet. Conventionally, the network-layer protocol is unaware of the link-layer changes, so IP datagrams to and from a moving node could be lost. Considerable system performance degradation might therefore result. This paper presents a scheme to integrate the handoff procedures of the two layers in the context of Mobile IP with route optimization. Experiment results show that our scheme is promising and can reduce packet loss due to host migrations substantially.

A VLSI algorithm for division in GF(2m) with the canonical basis representation is proposed. It is based on the extended Binary GCD algorithm for GF(2m), and performs division through iteration of simple operations, such as shifts and bitwise exclusive-OR operations. A divider in GF(2m) based on the algorithm has a linear array structure with a bit-slice feature and carries out division in 2m clock cycles. The amount of hardware of the divider is proportional to m and the depth is a constant independent of m.

This paper addresses a classic question about whether transmit power control (TPC) can increase the spectrum efficiency of a TDMA system and an FDMA cellular system as in the case of a DS-CDMA cellular system. Two types of TPC schemes are considered; one is slow TPC that regulates the distance dependent path loss and shadowing loss, while the other is fast TPC that regulates multipath fading as well as path loss and shadowing loss. In addition to TPC, antenna diversity reception is considered. The allowable interference rise factor χ, which is defined as the interference plus background noise-to-background noise power ratio, is introduced. The simple expressions for the signal-to-interference plus background noise power ratio (SINR) at the diversity combiner output using maximal-ratio combining (MRC) are derived to obtain the reuse distance by computer simulations. The impact of joint use of TPC and antenna diversity reception on the spectrum efficiency is discussed. It is found that the joint use of fast TPC and antenna diversity is advantageous and larger spectrum efficiency can be achieved than with no TPC. On the other hand, the use of slow TPC is found advantageous only for small values of standard deviation of shadowing loss; however, the improvement in the spectrum efficiency is quite small.

The advances in services using the present Internet mean that there will be increasing demand for Video on Demand (VoD) on the Internet in the near future. However, because of the best-effort characteristics of the Internet, it is important to suppress the degradation of communication quality caused by packet dropping when Internet traffic is congested. This paper focuses on MPEG transmission over the Internet, and suitable control mechanisms are established for an acceptable Quality of Service (QoS) improvement through detailed evaluation. Packets are classified using a frame-based scheme. The server applies the proposed End-to-End control scheme and shuffles the order of packets to avoid burst dropping, and may omit selected packets belonging to certain frames prior to forwarding. At the intermediate routers, transferred packets are transmitted according to Round Robin (RR) or Weighted Round Robin (WRR) scheduling, and are dropped statistically using selective Random Early Detection (RED) corresponding to frame attributes when there is congestion. We evaluate the proposed performance of transmission method using both computer simulations and empirical measurements of picture quality. The results show that when the traffic volume cannot be estimated in the intermediate routers, the combined use of RR, shuffling and conditional RED is effective, and when the traffic volume can be estimated, the combination of WRR, rate control and RED is effective.

In this paper, a new family of interconnection networks which we call the Incrementally Extensible Twisted Cube (IETQ) is proposed. The topology of this network is a novel generalization of the twisted cube. It inherits all the merits but without the limitations owned by a twisted cube. First, this proposed IETQ is incrementally extensible and can be adapted for use in any number of nodes; therefore, this network is particularly well suited for the design of a distributed communication network with an arbitrary number of nodes. Second, the vertex connectivity of IETQ is n. Measured by this vertex connectivity, we demonstrate that this network is optimally fault-tolerant . And it is almost regular, because the difference between the maximum and minimum degree of any node in an IETQ is at most one. A shortestpath routing algorithm for IETQ is proposed to generate path for any given pair of vertices in the network. Third, comparing with most of the other competitors, the diameter of this IETQ network is only half in size. This low diameter helps to reduce the internode communication delay. Moreover, IETQ also possesses the property of a pancyclic network. This attractive property would enable us to map rings of any length into the proposed network.

Since the invention of the RSA scheme, a lot of public-key encryption and signature schemes based on the intractability of integer factoring have been proposed. Most employ integers of the form N = p q, such as the RSA scheme, but some employ integers of the form N = pr q. It has been reported that RSA decryption speed can be greatly improved by using N = pr q integers for large r. On the other hand, Boneh et al. proposed a novel integer factoring method for integers such as N = pr q for large r. This factoring algorithm, the so-called Lattice Factoring Method, is based on the LLL-algorithm. This paper proposes a new method for factoring integers of the form N = pr q for large r and gives a new characterization of r such that factoring integers N = pr q is easier. More precisely, the proposed method strongly depends on the size and smoothness of the exponent, r. The theoretical consideration of and implementation of our method presented in this paper show that if r satisfies a certain condition our method is faster than both Elliptic Curve Method and Lattice Factoring Method. In particular, the theoretical consideration in this paper mainly employs the techniques described in the excellent paper by Adleman, Pomerance and Rumely that addresses primality testing.

This paper presents the analysis of integrated voice and data cellular networks with channel borrowing. Our considered system gives higher priority to handoff calls over new calls from users' point of view and reflects each characteristics of voice and data traffic types. Data handoff calls can wait in a queue while they are in handoff areas if there are no channels available. Voice handoff calls can borrow at most l channels from data calls if there are no idle channels upon their arrivals. We mathematically model this system by applying queueing theory. Then, we analyze its performance to derive the forced termination probability of data handoff calls, the blocking probabilities of the new and handoff calls of voice and data, and the Laplace Stieltjes transform for the distribution of waiting time in a queue. In numerical results, the analytical results for the mean waiting time of data handoff calls are compared with the simulation results to validate our analytical approach. Our system is also compared with the system where channel borrowing cannot be allowed (nonborrowing system) with respect to the blocking probabilities of the new and handoff calls of voice and data, the forced termination probability of data handoff calls, the mean and the coefficient of variation of the waiting time of data handoff calls.

This paper considers combining receptions with multiple receive antennas for space time coded MPSK signals over correlated Rayleigh fading channels. For the system with dual-antenna at receiver, a new transform is proposed, which can convert the correlated fading signals into uncorrelated ones. With the results obtained by using the proposed transform, the equivalent selective combining (SC) reception and maximum likelihood (ML) reception are presented. Theoretical analysis shows that ML reception has better performance than SC reception in terms of bit error rate. For the system with triple antenna at receiver, the simulation results are presented by using Monte Carlo method. All the results show that compared to using a receive antenna, a considerable signal to noise ratio gain can be obtained by using multiple receive antennas when the correlation coefficients among the receive antennas is not too high.