This paper investigates based on laboratory experiments the multiuser interference suppression effect of the coherent adaptive antenna array diversity (CAAAD) receiver employing an optical fiber feeder in the intermediate frequency (IF) stage, aiming at the practical use of adaptive antenna array beam forming techniques based on the W-CDMA air interface. We employed a configuration in which the optical fiber conversion, i.e., electrical-to-optical (E/O) conversion (vice versa (O/E)), is performed on a received signal amplified by an automatic gain control (AGC) amplifier in the IF stage, to abate the impact of the noise component generated by the E/O (O/E) converters. We first show by computer simulation the superiority of the optical fiber conversion in the IF stage to that in the radio frequency (RF) stage based on the achievable bit error rate (BER) performance. Furthermore, experimental results elucidate that the loss in the required transmit signal energy per bit-to-background noise power spectrum density ratio (Eb/N0) of the implemented CAAAD receiver at the average BER of 10-3 employing the optical fiber feeders in the IF stage compared to that with coaxial cables is within a mere 0.2 dB (six antennas, three users, two-path Rayleigh fading channel model, and the ratio of the target signal energy per bit-to-interference power spectrum density ratio (Eb/I0) of the desired user to that of the interfering users for fast transmission power control (TPC) is ΔEb/I0=-15 dB).

We consider the classification problem as a problem of approximation of a given training set. This approximation is constructed in a multiresolution framework, and organized in a tree-structure. It allows efficient training and query, both in constant time per training point. The proposed method is efficient for low-dimensional classification and regression estimation problems with large data sets.

In the paper, we propose a new method for chromatic dispersion measurement of WDM components in both transmission and reflection, employing photonic microwave technology. The dispersion can be determined by measuring the frequency spectrum range change of the microwave notch filter. The method features the advantages of low-cost and simplicity. Experimental results demonstrate that our setup is capable of measuring relative group delay with better than 1 ps time resolution and the measurement results show a good agreement with that measured by the conventional phase-shift technique.

A novel interference reduction method, transmit power and window control (TPWC), is proposed to enhance the system capacity in the downlink of code division multiple access (CDMA) cellular packet systems. TPWC measures the propagation conditions and calculates the required instantaneous transmit power between a base station (BS) and a mobile station (MS). Then, TPWC sends packets only during a transmit time-window, in which the packets can be sent with less power than a predetermined threshold. TPWC reduces the average transmit power at the cost of an extra transmission delay at the BS. Computer simulations show that TPWC enhances the system capacity by two-fold in a CDMA cellular packet system when each MS has a loading ratio of 0.5 and an average delay allowance of 5 ms for the unit packet length of 1 ms. Furthermore, this paper proposes a multi-link packet transmission (MLPT) scheme in order to reduce the delay caused by TPWC. When an MS is at the cell edge, packets are distributed by MLPT to multiple BSs, from which packets are sent to the MS; thus, the transmission delay can be reduced by utilizing the transmit windows of each BS.

We investigate the capacity limitations of a WDM ring fiber-radio backbone incorporating wavelength interleaving where each base station drives a sectorized antenna interface. We also investigate the issues related to the merging of such networks with standard WDM infrastructures. The investigations show that re-allocating the interleaved WDM channels to fit within a 100 GHz block enables the millimeter-wave (mm-wave) fiber-radio system with sectorized antenna interfaces to integrate easily with WDM systems. The performance of a variety of channel allocations for the merged fiber-radio network is examined and simulation studies of the transmission of multiple channels are carried out. The overall network capacity of the merged mm-wave fiber-radio network is improved with the proposed channel allocation schemes.

A Cyclotron Wave Converter, having decreased magnetic intensity is discussed. Two microwave cavities with uniform and quadruple (or six-pole) electric field in the gap of interaction are used to transform microwave power into the kinetic power of the electron beam fast cyclotron wave. As a result of it, magnetic flux density occurs in two (or three) times lower. The latter is very important to create a compact, powerful and efficient microwave/DC power converters operating at different frequencies including short centimetric and long millimetric wavebands.

We report on the first demonstration of single sideband (SSB) modulated time stretch system. In addition, we present an analytical model relating the system performance to the phase and amplitude mismatches in the SSB modulator. The results show that, fortuitously, the system is tolerant to such mismatches. In particular, using commercially available components,the dispersion induced power penalty can be kept below 2.5 dB over 4-20 GHz bandwidth for any stretch factor. The experiments demonstrate 120 Gsample/s real-time capture of a 20 GHz SSB-modulated microwave signal.

The fiber-optic sectorized remote antenna system by using the radio frequency (RF) optical transmission technique was promising for increasing the number of subscribers in the millimeter-wave broadband wireless access (MMW BWA) networks. To realize the cost-effectiveness of the fiber-optic sectorized remote antenna system covering four areas, we reached the conclusion that the best multiplexing schemes were the sub-carrier division multiplexing (SCM) of the intermediate frequency (IF) signals of 2 GHz for the down link, the coarse wavelength division multiplexing (CWDM) with the IF signals optical transmission for the up link and 1.3/1.55 µm-WDM for multiplexing the down link and the up link. In addition, the target specifications of this SCM-CWDM system were described, and the designs of the carrier to noise ratio (CNR) and the third order intermodulation distortion (IM3) were examined.

This paper presents a modified microwave radio-thermometer (MRTM) with material characteristic estimator and multiple temperature conversion tables to measure subcutaneous temperature of a living body. This estimator provides a temperature retrieval unit with material characteristics such as permittivity, conductivity, thickness and geometry of the living body. The temperature retrieval unit with multiple temperature conversion tables can select one of the tables and compute temperature value corresponding to measured radiation power. In the experiments, it was shown that the radio-thermometer could reduce measurement errors of about 0.82 to 7.68 for the cases of distilled water and mixed liquid # 5 with thickness of 29.5 cm and 9.5 cm at the temperature of 37.

An exact and an approximated reliabilities of a 2-dimensional consecutive k-out-of-n:F system are discussed. Although analysis to obtain exact reliability requires many calculation resources for a system with a large number of components, the proposed method obtains the reliability lower bound by using a combinatorial equation that does not depend on the system size. The method has an assumption on the maximum number of failed components in an operable system. The reliability is exact when the total number of failed components is less than the assumed maximum number. The accuracy of the method is confirmed by numerical examples.

This paper presents a review of volumetric erosion studies applied to electrical contacts. The numerical methods presented are generic and could equally be applied to a number of areas where surfaces have been eroded or damaged. Equally there is no scale limitation of the surfaces to which the numerical methods can be applied. The paper starts with an introduction of the issues associated with the measurement of contact erosion, and then presents a summary of various hardware system for making 3D measurements of surfaces such as electrical contacts. This is followed by a review of the generic form fitting methods and also volume calculation methods. The paper concludes with a review of results taken from a test system for contact studies and from contact samples taken from commercial relays.

Due to the rapid development of computer and information technology, 3D modeling and rendering capabilities are becoming increasingly important in many applications, including industrial design, architecture, CAD/CAM, video games, and medical imaging. Since 3D mesh models often have huge amounts of the data, it is time-consuming to retrieve from a storage device or to download from the network. Most 3D viewing applications need to obtain the entire file of a 3D model in order to display the model, even when the user is interested only in a low-resolution version of the model. Therefore, progressive coding that enables multiresolution transmission of 3D models is desired. In this paper, we propose the progressive coding scheme of 3D meshes with texture, in which we convert irregular meshes to semi-regular using texture coordinates, map them on planes, and apply 2D image coding algorithm to mesh compression. As our method uses the wavelet transform, the encoded bitstream has a progressive nature. We gain high compression rate with the same visual quality as original models.

We have thoroughly investigated the effect of on-chip decoupling capacitors on the simultaneous switching noise (SSN) and the radiated emission. Furthermore, we have successfully demonstrated an efficient design method for on-chip decoupling capacitors on an 8-bit microcontroller without increasing the die size, which results in more than 10 dB of suppressed radiated emission.

This paper proposes an enhanced method for multiple description coding (MDC) using whitening transform. The MDC using correlating transform is an error resilient coding technique that explicitly adds correlation between two descriptions to enable the estimation of one set from the other when one set is dropped in channel. This paper proposes a method to overcome practical problems that decoder must know statistics of original image in the conventional correlating transform method. The MDC using whitening transform does not need additional statistical information to reconstruct a image because the coefficients whitening transformed have uni-variance statistics. Our experimental results show that the proposed method achieves a good trade-off between the coding efficiency and the reconstruction quality. We obtain that PSNR of image reconstructed from two descriptions is about 0.93 dB higher at the 1.0BPP and PSNR from only one description is about 1.88 dB higher than conventional method at the same rate of 'Lena' image.

This paper proposes a new multispectral image data compression algorithm that can efficiently reduce spatial and spectral redundancies by applying classified prediction, a Karhunen-Loeve transform (KLT), and the three-dimensional set partitioning in hierarchical trees (3-D SPIHT) algorithm in the wavelet transform (WT) domain. The classification is performed in the WT domain to exploit the interband classified dependency, while the resulting class information is used for the interband prediction. The residual image data on the prediction errors between the original image data and the predicted image data is decorrelated by a KLT. Finally, the 3-D SPIHT algorithm is used to encode the transformed coefficients listed in a descending order spatially and spectrally as a result of the WT and KLT. Simulation results showed that the reconstructed images after using the proposed algorithm exhibited a better quality and higher compression ratio than those using conventional algorithms.

The interconnection problem of binary circuits becomes seriously as the exponential growth of the circuits complexity has been driven by a combination of down scaling of the device size and up scaling of the chip size. Motivated by the problem, there is much research of circuits based on multiple-valued logic. On the other hand, caused by the signal propagation delay, there exist hazards in binary logic circuits. To analyze hazards in binary logic circuits, many multiple-valued logics have been proposed, and studied on their mathematical properties. The paper will discuss on a multiple-valued logic which is suitable for treating static hazards in multiple-valued logic circuits. Then, the paper will show that the prime implicants expressions of r-valued logic functions realize static hazards free r-valued logic circuits.

Some electromechanical devices and systems produced using MEMS fabrication processes are detailed. Two precision measurement metrologies for inspecting electromechanical products are also described. As the trend of electromechanical devices has been towards smaller and smaller sizes possessing robust mechanisms and powerful functions, micro-electric-mechanical system (MEMS) devices are becoming more the choice for meeting such requirements. Three MEMS examples are discussed in detail in this paper: CMOS compatible sensors, RF/microwave components, and packaged and integrated passive devices. The design thinking of a new free-fall sensor, which is an accelerometer and possesses a surprisingly low frequency response and broad bandwidth, is mentioned. In addition, an AVID (dvanced ibrometer/nterferometer evice) system for measuring tiny displacement as well as a Morphinscope system that has the advantage of a confocal microscope combined with a photon tunneling microscope and both developed by NTU's MEMS/NEMS group, are discussed. The excellent sensing ability of the free-fall sensor and the accuracy resolution of the two measurement systems are proved by experimental verification.

The demand for wireless mobile communications has grown at a very high rate, recently. In order to solve the non-uniform traffic rates, the use of cell splits is unavoidable for balancing the traffic rate and maximizing total system capacity. For cell planning, a DS-CDMA cellular system can be comprise of different cell sizes because of different demands and population density of the service area. In this paper, we develop a general model to study the forward link capacity and outage probability of a DS-CDMA cellular system with mixed cell sizes. The analysis of outage probability is carried out using the log-normal approximation. When a macrocell is split into the three microcells, as an example, we calculate the multi-cross interferences between macrocells and microcells, and the forward link capacities for the microcells and the neighboring macrocells. The maximum allowable capacity plane for macrocell and microcell is also investigated. The numerical results and discussions with previous published results of reverse link are summarized.

In this paper, to enhance the power efficiency a new simple space-time coding scheme is devised with application to the OFDM based Wireless LAN system. The basic idea is from the receiver's point of view and is referred to as Virtual Constellation Mapping (VCM). We designed a new combination of the channel coding (Turbo Code) along with multiple transmit antennas (Two antennas) to achieve transmit diversity and space division multiplexing transmission. Computer simulation results showed that with the same transmission data rate, our proposed scheme can achieve better bit error rate (BER) compared with the conventional space-time trellis coded OFDM scheme in high Doppler fading channels.

The authors have been interested in a Scanning Laser Microscope (SLM) and applied it to studies of contact phenomena. In particular, a digital SLM is being currently used, and confirmed to be a successful tool for investigating the contact phenomena. In this paper, the theory and mechanism of a digital SLM are briefly explained, and some actual data obtained with the digital SLM are presented for demonstrating its usefulness for studies of contact phenomena.