There are methods used to test the optical purity of enantiomers; however, most of the simple methods are not precise and more complicated methods are better. As a result, these methods cannot be widely used for industrial purposes. The aim of this research is to design a sensor which can discriminate D-amino acids from L-amino acids. The designed sensor has chiral membranes and uses the technique of impedance change of these chiral membranes to discriminate the amino acids. We used a noise-FFT (Fast Fourier Transform) technique to determine the membrane impedance. When an enantiomer membrane resides in a chiral environment, (E*), diastereomeric interactions (E*-D) and (E*-L) are created, which may differ sufficiently in the arrangement of molecules of the membranes so as to permit the discrimination of optical substances due to the change in membrane characteristics. With increasing concentrations of the amino acids, the membrane resistance changes depended on the optical activity of the amino acids. The results suggest that the impedance changes of the chiral membrane with diastereomeric reaction can be used for the high-performance chemical sensor to measure the optical purity of different substances.

A simple but efficient method to improve readability of discrete pseudo time-frequency representations (TFRs) of nonstationary signals by the reassignment of the representations in discrete frequency dimension is presented. The method does not rely on the nonzero time derivative of the window function employed in the estimation of pseudo TFR. This property of the reassignment method is advantageous because the method can provide an improved readability in the situation when a known reassignment method is unefficient. The reassignment of the TFRs of corrupted signals is discussed. Numerical examples are included to illustrate the performance of the proposed method.

I describe a software reliability growth model that yields accurate parameter estimates even with a small amount of input data. The model is based on a proposed discrete analog of a Gompertz equation that has an exact solution. The difference equation tends to a differential equation on which the Gompertz curve model is defined, when the time interval tends to zero. The exact solution also tends to the exact solution of the differential equation when the time interval tends to zero. The discrete model conserves the characteristics of the Gompertz model because the difference equation has an exact solution. Therefore, the proposed model provides accurate parameter estimates, making it possible to predict in the early test phase when software can be released.

In the food, beverage and cosmetic industry and so on, odor sensing systems instead of human sensory test are demanded. We have developed odor sensing systems using QCM (quartz crystal microbalance) sensor array and pattern recognition method. Since the properties of the sensors depend on the gas sorption characteristics of the sensing films coated on them, the optimum films according to target odors should be selected. In this study, we tried to select sensing films appropriate for discrimination of slightly different apple flavors. The examples of typical apple flavors were prepared blending 9 compounds. The sensing films were extracted from various kinds of materials such as lipid, stationary phase material of GC (gas chromatography) and cellulose. The selection method under the condition of the small number of measurements was studied. We analyzed the data of steady-state sensor responses in terms of the Euclidean distance, and the films appropriate for apple flavor discrimination were successfully selected.

Layer-by-layer sequential adsorption process of polyelectrolytes had conventionally been used for the fabrication of the ultra-thin organic film formed by various polymers with different polarity of charge. In this study, hydrophobic Ruthenium complex monomer (tris (bilyridyl) ruthenium (II) hexafluorophosphate) was micelle-wrapped with an anionic surfactant, sodium dodecylbenzenesulfonate, and was assembled with PAH (poly (allylamine hydrochloride)) which has the opposite charge on ITO substrates. With this method, we succeed in fabricating ultra-thin organic films even when the adsorption material is not polymer but monomer. Moreover it was found that the bilayer thickness of the self-assembled (Ru micelle/PAH) was systematically changed by adjusting the solution pH of each bath. By using this process, EL device was fabricated by depositing the thin film of micelle-wrapping ruthenium complex monomer on ITO and formed Bi electrode on top of the film. Light emission was observed by applying voltage to this device.

We propose a novel Bragg grating filter synthesis method using a Fourier transform of the target scattering matrix. Multiple scattering processes are taken into account by iteration to improve the synthesis accuracy.

In static multiprocessor scheduling, heuristic algorithms have been widely used. Instead of gaining execution speed, most of them show non promising solutions since they search only a part of solution spaces. In this paper, we propose a scheduling algorithm using the genetic algorithm (GA) which is a well-known stochastic search algorithm. The proposed algorithm, named ordered-deme GA (OGA), is based on the multiple subpopulation GA, where a global population is divided into several subpopulations (demes) and each demes evolves independently. To find better schedules, the OGA orders demes from the highest to the lowest deme and migrates both the best and the worst individuals at the same time. In addition, the OGA adaptively assigns different mutation probabilities to each deme to improve search capability. We compare the OGA with well-known heuristic algorithms and other GAs for random task graphs and the task graphs from real numerical problems. The results indicate that the OGA finds mostly better schedules than others although being slower in terms of execution time.

This paper proposes a survivor-correction Viterbi algorithm (SCVA) and presents its application to an iterative sequence estimation in order to improve bit error rate performance of decision-feedback sequence estimation (DFSE) in the presence of intersymbol interference. The SCVA can mitigate erroneous survivor selections due to DFSE, because it modifies the add-compare-select operation to an add-correct-compare-select operation. Finally, it is confirmed by computer simulation that complexity of the proposed scheme is independent of delay of the main delayed ray and its performance is superior to that of DFSE at the same number of states.

Today's market share of Intelligent Network (IN) service is growing rapidly in wireless networks due to the rapid advances in wireless telecommunication and IN technology. To guarantee network independent IN services, mobility of IN service subscribers has to be taken into account. This paper proposes new designs of Global Service Logic for the IN service enhancement, which increase call completion rates in wired and wireless intelligent networks. In order to apply this logic to wireless service subscribers as well as wired service subscribers, we implement a Queue Manager applied to the call queuing service feature in the Service Control Point (SCP). In the case of wireless service subscribers, the Home Location Register (HLR) handles the service registration flags to notify the Queue Manager of the corresponding service subscribers' mobility. In addition, we present a dynamic queue management mechanism, which dynamically manages the queue size based on the parallel server queuing model as the wireless subscribers roam the service groups due to their mobility characteristics. In order to determine the queue size allocated by the dynamic queue manager, we simulate the relationship between the number of the subscriber's terminals and the drop rate by considering the service increment rate. Moreover, the appropriate waiting time in the queue as required is simulated according to the above relationship. We evaluate call completion rates of the proposed mechanism in the paper by comparing to that of the existing mechanism.

In this paper, a new frequency transformation for complex analog filter design which is suitable for integration is discussed. Arbitrary specified passband and stopband edges are easily transformed into those of the normalized LPF by solving simultaneous equations with four unknowns. Different from previous methods, the proposed transformation provides better performance in active realization of complex filters.

The transmission performance of WDM transmission systems is influenced by many effects according to the type of optical fiber employed in the system. Japanese high-speed transmission systems use dispersion-shifted fiber (DSF). It is well known that the transmission distance of WDM systems employing DSF is restricted by fiber four-wave mixing (FWM). Unequally spaced channel allocation (USCA) was proposed to mitigate the FWM effect. However, if no FWM light is allowed to fall on any optical channel, the number of channels is limited. This paper proposes a new method to extend the number of USCA channels to more than 16 under the optical bandwidth limitation. This method determines channel allocation by considering the distribution of the zero-dispersion wavelength of the optical fiber. The transmission performance of a WDM transmission system employing the proposed USCA methodology is clarified by numerical simulation to confirm that the optical bandwidth requirements can be reduced without degrading transmission performance. As a result, for 16 2.5 Gbit/s, if the fiber input power ranges from -3 dBm/ch to 3 dBm/ch, the achievable transmission distance is 700 km; the fluctuation in zero-dispersion wavelength is assumed to have the standard deviation of 5 nm. For 16 10 Gbit/s, if the fiber input power ranges from 0 dBm/ch to 3 dBm/ch, the achievable transmission distance is 400 km.

An optimum representative-frames (r-frames) selection method using step-wise function approximation has been developed to provide automatic indexing for a video-query-agent (VQA) system. It uses dynamic programming to simultaneously select the r-frames and corresponding segment boundaries. Experiments showed that the approximation error of the selected r-frames was less than that of two conventional methods. Retrieval experiments using a feature-based image-search engine showed that the proposed method is more robust and effective than the two conventional methods. The proposed method was implemented in a VQA system and processing time was evaluated. The results showed that the processing time for indexing was shorter than that of the conventional method.

We propose a rough classification system using Hierarchical Learning Vector Quantization (HLVQ) for large scale classification problems which involve many categories. HLVQ of proposed system divides categories hierarchically in the feature space, makes a tree and multiplies the nodes down the hierarchy. The feature space is divided by a few codebook vectors in each layer. The adjacent feature spaces overlap at the borders. HLVQ classification is both speedy and accurate due to the hierarchical architecture and the overlapping technique. In a classification experiment using ETL9B, the largest database of handwritten characters in Japan, (it contains a total of 607,200 samples from 3036 categories) the speed and accuracy of classification by HLVQ was found to be higher than that by Self-Organizing feature Map (SOM) and Learning Vector Quantization methods. We demonstrate that the classification rate of the proposed system which uses multi-codebook vectors for each category under HLVQ can achieve higher speed and accuracy than that of systems which use average vectors.

This paper conducts performance evaluation for a code division multiple access (CDMA) system when channel bands of multiple neighboring CDMA/DSSS are overlapped in frequency domain. It is assumed that all systems adopt direct-sequence spread-spectrum (DSSS) technique and are BPSK modulated by the different carrier frequencies. Automatic power control (APC) is also applied in the interfered system such that the receiver gets the same power from all users. Without loss generality, an additive white Gaussian noise (AWGN) channel is also assumed during analysis. In this paper, the analytic solution of the signal to noise ratio (SNR) is first derived in which both CDMA systems are modulated by different carrier frequencies. This analysis is good for general cases; and the result shows an excellent computational performance. In particular, the result is very close to Pursly's result, when the systems have the same code length with no carrier difference.

This paper investigates the turbo equalization techniques for wireless cellular systems. Simulation results over three GSM channel models are presented.

We propose a novel adaptive multiple-symbol differential detection (MSDD) scheme that has excellent performance over frequency selective fading (FSF) channels. The adaptive MSDD scheme consists of an adaptive noncoherent least mean square channel estimator that can accomplish channel estimation without any decision delay and the MSDD. The M-algorithm is introduced into this detection scheme to reduce the complication of computation due to increasing observed sequence length in the MSDD. Because of the application of the adaptive channel estimator and the M-algorithm, this adaptive MSDD make it possible that channel estimation is accomplished for every symbol along M surviving paths without any decision delay. And the SER performance of this adaptive MSDD is not affected by phase fluctuation introduced by a channel because the MSDD and the noncoherent channel estimator are applied. The adaptive MSDD scheme is applied to typical constellation of 16APSK, the (4,12) QAM and the star QAM. The excellent tracking performance of this adaptive MSDD scheme over FSF channels is confirmed by computer simulations.

This paper describes a CORDIC-based direct digital frequency synthesizer in comparison with a ROM-based architecture. To optimize the hardware design parameters, we perform numerical analysis of the quantization effects for ROM and CORDIC-based architectures. The hardware costs of them are estimated in FPGA, which shows that the CORDIC-based architecture becomes better than the ROM-based when the required accuracy is 9 bits or more.

We report a new type of electrooptic deflector using lens effect which is able to scan a space in two dimensions. The proposed device was developed from a quasi-velocity-matched electrooptic phase modulator with periodic domain inversion, therefore, it can operate efficiently at a microwave frequency. In the experiments, the demonstration of its operation and applications to ultrafast light control was done at 16.25 GHz.

1.5 µm-band LiNbO3 quasiphase matched (QPM) wavelength converters consisting of a periodical domain inverted structure and a proton exchanged waveguide, have been studied in detail both theoretically and experimentally. Optimum device fabrication conditions are investigated with respected to waveguide propagation loss, coupling loss to a single-mode fiber and wavelength conversion efficiency. A normalized conversion efficiency as high as 200 %/W (by a SHG measurement) and a fiber-to-fiber insertion loss of less than 3.5 dB (@1.55 µm) is obtained for a wavelength converter module with a device length of 40 mm. It is shown that a highly uniform periodical domain inverted structure and a uniform proton exchange waveguide are key to obtaining efficient wavelength conversion. The tolerance of the waveguide width fluctuation is found to be very critical and is less than 20 nm for a 40 mm-long device. Future optimization of LiNbO3 QPM wavelength converters and the possible device applications in future optical communication systems are also presented.

We studied theoretically and experimentally an InGaAs/InAlAs/InP polarization-insensitive multiple quantum well (MQW) electroabsorption (EA) modulator operating over a very wide wavelength range in 1.55 µm wavelength region. One of the simplest possible potential-tailored quantum well, "pre-biased" quantum well (PBQW) is used to achieve wide-wavelength polarization insensitivity. PBQW is basically a rectangular quantum well with a thin barrier inserted near one edge of well. This thin barrier effectively introduces "pre-bias" to a rectangular quantum well and the same amount of Stark shift is achieved for electron-heavy hole and electron-light hole transition energies. By incorporating tensile strain into PBQW, polarization-insensitive modulation is achieved over 60 nm wavelength range, from 1510 nm to 1570 nm. This MQW-EA modulator plays an important role in wavelength division multiplexing (WDM) transmission and switching systems.