Inter-domain communications on a chip require a synchronizer to resolve the timing problems between an input and a clock of a destination. This paper presents a parallel flop synchronizer and its interface circuit for transferring asynchronous data to the clock domain. The proposed scheme uses a bank of independent two-flops in parallel and supports a two-phase handshake protocol. Compared to the conventional two-flop synchronizer, performance analysis shows that the proposed scheme can reduce latency up to one and a half of clock cycles while retaining its safety to a tolerable level. All designs have been implemented in a 0.25 µm CMOS technology to verify performance analysis of the proposed synchronization.

In this paper, we propose four different strategies of node pair selection in multiple input multiple output (MIMO) interference channel where interference alignment (IA) is considered as a transceiver design method. In the first scheme, we consider the maximization of the sum rate by selecting node pairs in a brute force way. We also propose a sub-optimal sum rate maximization scheme with lower complexity than the first scheme. In the third scheme, we aim to minimize the number of links among pairs which incurs the outage in MIMO interference channel. In the fourth scheme, we suggest a max-min node pair selection scheme to enhance both the sum rate and the outage probability. Simulation results demonstrate that all our proposed node pair selection schemes can increase the sum rate but also while also reducing the outage probability compared to the scheme with random node pair selection.

A label is given to each vertex of three views of a solid object. The relations among three dimentional vertices are obtained from a labeled tree. A face extracting algorithm by the tree searching method is reported with an example.

In the integrated Wireless LAN (WLAN) and cellular networks, power efficiency is one of the most important aspects as in existing wireless networks. Especially, we note that in the idle state, a mobile device with dual interfaces needs to receive periodic beacons from the access point and downlink control information from the base station, resulting in significant power consumption. To save the power, we propose a power saving scheme with Hibernation mode to completely turn off the WLAN interface during the idle state, instead of entering Power Save (PS) mode and turn it on only when there is a need to receive data. However, if the WLAN interface is turned on even for a momentary traffic, it must repeat turning on and off continuously, dissipating power. Thus, we also develop a Mobile IPv6 (MIPv6)-based signaling to turn on the WLAN interface for long-lived traffic. It is shown via simulations that the proposed power saving scheme results in better power efficiency.

Modern video compression usually consists of ME/MC (Motion Estimation/Motion Compensation), transform, and quantization of the transform coefficients. Efficient bit allocation technique to distribute available bits to motion parameters and quantized coefficients is an important part of the whole system. A method that is very complex and/or needs buffering of many future frames is not suitable for real time application. We develop an efficient bit allocation technique that utilizes the estimated effect of allocated bits to motion parameter and quantization on the overall quality. We also propose an hierarchical block based ME/MC technique that requires less computations than classical BMA (Block Matching Algorithm) while offering better motion estimation.

In this paper, we propose a multi-cell structure backscatter based wireless-powered communication network (WPCN) where a number of backscatter cells are locally separated, each containing a subset of users around a carrier emitter. The multi-cell structure backscatter based WPCN can be implemented in two ways, namely time-division multiplexing (TDM) and frequency-division multiplexing (FDM). Here users harvest energy from the carrier signal transmitted by the carrier emitter, and then transmit their own information in a passive way via the reflection of the carrier signal using frequency-shift keying modulation. We characterize the energy-free condition and the signal-to-noise ratio (SNR) outage zone in a backscatter based WPCN. Also, a backscatter based harvest-then-transmit protocol is adopted to maximize the sum-throughput of all users by optimally allocating time for energy harvesting and information transmission. Numerical results demonstrate that the backscatter based WPCN ensures an increased long-range coverage and a diminished SNR outage zone compared to conventional radio based WPCNs. Also, comparing the two types of multi-cell structure backscatter based WPCN, TDM within each backscatter cell and FDM across backscatter cells versus FDM within each backscatter cell and TDM across backscatter cells, numerical results confirm that which one yields a better performance.

This letter proposes a novel dynamic channel assignment (DCA) scheme to improve the downlink system capacity in heterogeneous networks (HetNets) with fractional frequency reuse (FFR). In the proposed DCA scheme, the macro base station (MBS) finds small-cell base stations (SBSs) that give strong interference to macro user equipments (MUEs) and then dynamically assigns subchannels to the SBSs to serve their small-cell user equipments (SUEs) according to the cross-tier interference information to MUEs. Through simulation results, it is shown that the proposed DCA scheme outperforms other schemes in terms of the total system capacity.

In this paper, we investigate an inherent noise reduction characteristic of a modulated orthogonal sequence. The modulated orthogonal sequence generates length N2 sequences from N information symbols. Using the amplitudes of received sequences, we first estimate the smallest amplitude noise. Then the noise is reduced by the proposed scheme. The noise reduction scheme is shown to have an excellent performance in non-Gaussian noise environment.

Synthetic aperture radar interferometry have been established in the past two decades, and used extensively for many applications including topographic mapping of terrain and surface deformation. Vegetation analysis is also a growing area of its application. In this paper, we propose an polarimetric SAR interferometry technique for interferometric phase extraction of each local scatterer. The estimated position of local scattering centers has an important information for effective tree height estimation of forest. The proposed method formulated for local scattering center extraction is based on the ESPRIT algorithm which is known for high-resolution capability of closely located incident waves. The method shows high-resolution performance when local scattered waves are uncorrelated and have different polarization characteristics. Using the method, the number of dominant local scattering centers and interferometric phases in each image pixel can be estimated directly. Validity of the algorithm is demonstrated by using examples derived from SIR-C data.

A mutated adder architecture utilizing a mixture of carry propagation schemes is proposed to design a delay-area efficient adder which were not available in an ordinary design space. Further, we develop an optimization method based on integer linear programming to search the expanded design space of the mutated adder.

A novel self-alignment process using the surface tension of the liquid resin for assembly of electronic or optoelectronic devices in 3-D space has been proposed. The vertical alignment can be controlled by using of metal sphere, reducing the necessary precise process control such as solder volumes and external forces, and allowing large tolerances in liquid volume and misalignment. Lateral alignment could be also achieved by making the liquid resin constrained on the 3-dimensional pads on chip and substrate. This study focused on the principle of self-alignment and final alignment accuracy. In addition, the possibility of self-alignment process was verified by analytic numerical method and scaled-up experiment. An average alignment accuracy of less than 0.25 µm has been obtained. It is thought that this process is effective for assembly simply at low process temperature, low cost and without flux in future assembly techniques.

Super resolution (SR) reconstruction is the process of fusing a sequence of low-resolution images into one high-resolution image. Many researchers have introduced various SR reconstruction methods. However, these traditional methods are limited in the extent to which they allow recovery of high-frequency information. Moreover, due to the self-similarity of face images, most of the facial SR algorithms are machine learning based. In this paper, we introduce a facial SR algorithm that combines learning-based and regularized SR image reconstruction algorithms. Our conception involves two main ideas. First, we employ separated frequency components to reconstruct high-resolution images. In addition, we separate the region of the training face image. These approaches can help to recover high-frequency information. In our experiments, we demonstrate the effectiveness of these ideas.

In this letter, we introduce two different resource allocation and Tx power management schemes, called resource control and fixed power (RCFP) and fixed resource and power control (FRPC), in an LTE-Advanced femtocell network. We analyze and compare the two schemes in terms of the system throughput for downlink and energy consumption of home evolved NodeB (HeNB) Tx power according to the number of HeNBs and home user equipment (HUE)'s user traffic density (C). The simulation results show that the FRPC scheme has better performance in terms of system throughput for macro user equipments (MUEs) and energy consumption in low C.

In this paper, we propose a novel scheme to optimize the allocation of continuous queries in a sensor network with multiple sinks. The existing scheme compares the coverage areas of given queries and estimates the amount of sharing among them. It tries to allocate queries to the optimal sink that maximizes the amount of sharing and reduces the communication costs among sensor nodes and sinks. However, it inefficiently allocates continuous queries. The amount of sharing among continuous queries depends not only on their coverage area but also on their time-parameters like time-duration and time-interval. We define a new cost estimator with time-parameters for continuous queries and optimize their allocation in the sensor network. Simulation results show that our scheme performs the allocation of continuous queries efficiently and reduces the communication cost.

This letter proposes a vertical handoff scheme for integrated WLAN and UMTS that use the mobile Internet Protocol (IP) to reduce the packet loss caused by the ping-pong effect for high mobility users. The simulation results show that the proposed scheme efficiently increases the throughput of high mobility users.

We propose a new offline check system that allows refunds to be reused in payments. In this system, a shop issues a new check, called a refund check, for the change. The form of the refund check is much simpler than that of existing checks, and uses a more flexible and efficient denomination method. The new system also provides tracing mechanisms to counter criminal acts and considers the atomicity of transactions occurring in the system.

In order to exploit the benefits of soft handoff, finding good values of handoff control parameters is important. In cellular system specifications such as IS-95C and WCDMA, handoff decision algorithm includes signal strength averaging and drop timer in addition to hysteresis. This paper analyzes the effects of signal strength averaging and drop timer and their performance tradeoffs. Because averaging and drop timer are both based on time delay, one may expect that they have similar impact on soft handoff performance. The results show that the effects of averaging and drop timer are rather similar and closely connected in terms of reducing the signaling overhead. However, they have different impacts on resource usage and diversity gain of the system.

For analog applications, the Metal-Insulator-Metal (MIM) capacitance has to be measured at a much higher resolution than using the conventional methods, i.e. to a sub-femto level. A new robust mismatch measurement technique is proposed, which is more accurate and robust compared to the conventional Floating Gate Capacitance Measurement (FGCM) methods. A capacitance mismatching measurement methodology based on Vs is more stable than that based on Vf because the influence of pre-existing charge in the floating-gate can be cancelled in the slope of ΔVs/ΔVf based on Vs. The accuracy of this method is evaluated through silicon measurement in a 0.13 µm technology. It shows that, compared to the ideal value, the average of the new method are within 0.12% compared to 49.23% in conventional method while the standard deviation is within 0.15%.

This paper proposes a novel feature selection method for the fuzzy neural networks and presents an application example for 'personalized' facial expression recognition. The proposed method is shown to result in a superior performance than many existing approaches.

In future mobile networks, the ever-increasing loads imposed by mobile Internet traffic will force the network architecture to be changed from hierarchical to flat structure. Most of the existing mobility protocols are based on a centralized mobility anchor, which will process all control and data traffic. In the flat network architecture, however, the centralized mobility scheme has some limitations, such as unwanted traffic flowing into the core network, service degradation by a single point of failure, and increased operational costs, etc. This paper proposes mobility schemes for distributed mobility control in the flat network architecture. Based on the Proxy Mobile IPv6 (PMIP), which is a well-known mobility protocol, we propose the three mobility schemes: Signal-driven PMIP (S-PMIP), Data-driven Distributed PMIP (DD-PMIP), and Signal-driven Distributed PMIP (SD-PMIP). By numerical analysis, we show that the proposed distributed mobility schemes can give better performance than the existing centralized scheme in terms of the binding update and packet delivery costs, and that SD-PMIP provides the best performance among the proposed distributed schemes.