bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphodiesterase 5 inhibitors lower both portal and pulmonary pressure in portopulmonary hypertension: a case report
Authors: Bremer Hinrich C , Kreisel Wolfgang , Roecker Kai , Dreher Michael , Koenig Daniel , Kurz-Schmieg Anna Katharina , Blum Hubert E , Roessle Martin , Deibert Peter
Published: July 2007

Background

Portopulmonary hypertension (PPHTN) is a severe complication in liver cirrhosis. PDE5 inhibitors lower pulmonary arterial pressure (PAP) in PPHTN. However, their effect on portal hypertension has not yet been investigated.

Case presentation

A 55 year old male patient presented with PPHTN and alcoholic liver cirrhosis. 10 mg of Tadalafil, a PDE5 inhibitor with a long half-life, was administered orally under continuous monitoring of pulmonary and portal hemodynamics. For maintenance therapy the patient received Sildenafil 20 mg bid.

Tadalafil lowered mean PAP from 45 to 39 mmHg within 60 minutes. Cardiac output (CO) increased from 6.8 to 7.9 l/min. Central venous pressure (CVP) remained stable at 3 mmHg. Systolic and diastolic blood pressure was lowered from 167/89 to 159/86 mmHg. Pulse rate increased from 75 to 87 per min. Wedged hepatic vein pressure (WHVP) decreased from 21 to 18 mm Hg, hepatovenous pressure gradient (HVPG) decreased from 10 to 7 mmHg. Hemodynamic monitoring after 6 months of Sildenafil therapy revealed a sustained lowering of mean PAP. HVPG remained constant at 10 mmHg. Cardiac and pulmonary performance had further improved.

Conclusion

This case report shows for the first time, that phosphodiesterase 5 inhibitors lower both portal and pulmonary pressure in portopulmonary hypertension.
Is Kate Winslet more American than Lucy Liu? The impact of construal processes on the implicit ascription of a national identity
Authors: Devos Thierry , Ma Debbie S.
Published: July 2007

In four studies, we investigated the role of person construal on the implicit ascription of a national identity. Participants completed Implicit Association Tests (Studies 1 and 3) or Go/No‐go Association Tasks (Studies 2 and 4) assessing the extent to which the concept American was linked to an Asian American celebrity (Lucy Liu) and to a White European celebrity (Kate Winslet). In contrast to explicit responses, the Asian American target was implicitly regarded as being less American than the White European target. This effect was more pronounced when targets were categorized based on their ethnic (rather than personal) identity (Studies 1 and 2) and when the exemplars draw attention to the ethnic identity of the Asian American target (Studies 3 and 4). These findings provide evidence for the flexibility of construal processes and the role of ethnicity in the implicit ascription of a national identity.
Skull size and shape ofDasymys(Rodentia, Muridae) from sub-Saharan Africa
Authors: Mullin Sarah K. , Taylor Peter J. , Pillay Neville
Published: July 2007

Three morphological datasets (traditional measurements, dorsal and ventral skull shape coordinates) were used to examine craniometric variation in the water ratDasymys, a genus found throughout sub-Saharan Africa. This study is the first to examine the entire genus as well as to statistically compare taxa within the genus to the nominate speciesD. incomtus. Morphological data confirmed that the five species recognised by Musser & Carleton (1993);D. incomtus, D. foxi, D. nudipes, D. montanusandD. rufulus, represent valid morphological species although two of the species do not encompass the geographic areas presently assigned to them.Dasymys rufulusoccupies a larger range andD. incomtusa much smaller range than previously suggested withD. rufulusappearing to be part of a species complex. Furthermore, we discerned six additional morphological species resulting from the elevation of four subspecies (D. i. capensis, D. i. griseifrons, D. i. mediusandD. i. longipilosus) and the recognition of two new species:D. shortridgei(restricted to the Okavango Delta) andD. robertsii(occurring in the Limpopo and Mpumalanga Provinces of South Africa).
Laser Cooling and Trapping of Neutral Atoms
Authors: Metcalf Harold J. , van der Straten Peter
Published: July 2007

This article presents a review of some of the principal techniques of laser cooling and trapping that have been developed during the past 20 years. Its approach is primarily experimental, but its quantitative descriptions are consistent in notation with most of the theoretical literature.
Crystallization of Amorphous SiO2 Microtubes Catalyzed by Lithium
Authors: Zhao L. , Li N. , Langner A. , Steinhart M. , Tan T. Y. , Pippel E. , Hofmeister H. , Tu K.‐N. , Gösele U.
Published: July 2007

Amorphous silica formed by thermally oxidizing silicon is commonly eligible for lithographic patterning or can be grown on patterned substrates. However, it is still a challenge to combine controlled microstructuring with controlled crystallization of SiO2. Here, it is shown that traces of volatile lithium species transported through the gas phase catalyze the crystallization of silica integrated into common silicon microstructures. The selected crystallization temperature determines which polymorph forms. As an example, the formation of quartz, tridymite, and cristobalite microtubes by thermally oxidizing macroporous silicon is investigated. Lithium‐induced crystallization may extend state‐of‐the‐art silicon technology and yield nano‐ and microstructures consisting of different silica polymorphs, which are, in contrast to many functional oxides, nontoxic.
Octahydroxypyridine[4]arene Self‐Assembles Spontaneously To Form Hexameric Capsules and Dimeric Aggregates
Authors: Evan‐Salem Tamar , Cohen Yoram
Published: July 2007

In recent years it has been observed that resorcin[4]arenes and pyrogallol[4]arenes form hydrogen‐bonded hexameric capsules in nonpolar solvents. In the present study we have used NMR spectroscopy, with an emphasis on diffusion NMR, to investigate the self‐assembly and the aggregation mode of solutions of octahydroxypyridine[4]arene (1 b) in chloroform. In spectroscopic studies, the hexameric capsule of C‐undecylresorcin[4]arene (2 b) was used as a reference compound and in some cases also as an internal reference. The current diffusion NMR spectroscopy study shows, in contrast to a previous report, that compound 1 b self‐assembles spontaneously into hexameric and dimeric aggregates in solutions in chloroform. The 1H NMR and diffusion NMR spectroscopic studies on a solution of 1 b in CHCl3 show the presence of new upfield‐shifted peaks, which diffuse with the same diffusion coefficient as the hexameric peaks in the spectrum. Therefore, these new upfield‐shifted peaks were attributed to encapsulated CHCl3 molecules. Interestingly, diffusion NMR measurements showed that the addition of trifluoroacetic acid (6.7 equiv), which had no effect on the hexameric capsules of 2 b, led to the disassembly of the hexamer and the dimer of 1 b into its monomers. Therefore, we conclude that compound 1 b self‐assembles spontaneously into hexameric capsules in nonpolar organic solvents, as do resorcin[4]arenes 2 b and 2 c and pyrogallol[4]arenes 3 a and 3 b.
Recent and Expected Roles of Plasma‐Polymerized Films for Biomedical Applications
Authors: Förch R. , Chifen A. N. , Bousquet A. , Khor H. L. , Jungblut M. , Chu L.‐Q. , Zhang Z. , Osey‐Mensah I. , Sinner E.‐K. , Knoll W.
Published: July 2007

This review aims to provide a summary of some of the challenges in correlating surface science and biology, with particular emphasis on areas where plasma polymerization has and will play an important role as a method to synthesize reproducible and well‐defined surfaces. Since the range of possible applications of plasma polymer films in biomaterial applications is immense, this paper will focus on processes to develop various surface morphologies and chemical structures for the immobilization of proteins and cells. Functional, plasma‐polymerized films are discussed as biosensitive interfaces that may ultimately be part of a multilayer system that aims at connecting inorganic/metallic transducers with biologically reactive surfaces. These topics will be reviewed with some experimental results taken from the authors' own work. Specific aspects such as adhesion improvement and solvent effects are also discussed.
Special Issue on Low‐Pressure Plasma‐Enhanced CVD
Authors: Gordillo‐Vázquez Francisco J.
Published: July 2007

Low‐pressure plasma‐enhanced CVD (PECVD) is the topic of this Special Issue of Chemical Vapor Deposition. In this brief introduction, Guest Editor Francisco Gordillo‐Vázquez outlines the potential of PECVD for new and emerging applications and introduces the papers in the issue that give a clear insight into low‐pressure PECVD research as it stands at the moment.
Novel use of the fluorescent dye 5‐(and‐6)‐chloromethyl SNARF‐1 acetate for the measurement of intracellular glutathione in leukemic cells and primary lymphocytes
Authors: Hamilton David , Loignon Martin , Alaoui‐Jamali Moulay A. , Batist Gerald
Published: July 2007

Glutathione (GSH) plays an important role in protecting cells against injury, particularly during oxidative stress. Alterations in GSH metabolism are becoming the focus of attention in many diseases such as cancer, neurodegeneration, and AIDS. As such, a rapid assessment of GSH levels in a clinical setting is of increasing importance. We tested the efficacy of the thiol‐labeling fluorescent dye CM‐SNARF in its ability to measure variations in GSH concentration using a visible‐light flow cytometer. GSH levels in I83, Jurkat, and primary lymphocytes were depleted with buthionine sulfoximine (BSO) or diamide, or increased with N‐acetylcysteine (NAC). Following each treatment, cells were divided and either labeled with CM‐SNARF followed by flow cytometry analysis, or assayed for GSH using a biochemical method. BSO treatment caused a maximal 87–90% decrease in GSH and 68–76% decrease in fluorescence units. Diamide depleted GSH 91–95%, corresponding to a fluorescence decrease of 85–88%. NAC treatment increased GSH levels 27% and fluorescence 12–19%. The overall correlation (R2) between mean GSH concentration and mean fluorescence was 0.80–0.88. CM‐SNARF can be used to semi‐quantitatively and rapidly determine intracellular variations in GSH concentration in the range of 10–150 nmoles GSH/mg protein. © 2007 International Society for Analytical Cytology
Period‐doubling phenomena and chaos generated in the GaAs ring‐oscillator
Authors: Akamatsu Norio
Published: July 2007

GaAs MESFET has the Schottky gate structure, in contrast to Si MOSFET. Consequently, the gate current increases rapidly when the gate voltage exceeds the Schottky voltage. In the direct‐coupled FET logic circuit (DCFL) using GaAs, when the input voltage is increased, a minimum is produced in the input‐output transfer characteristic in the low‐output voltage region. Because of this property, when a ring‐oscillator is constructed by cascading DCFL, a perioddoubling phenomenon is produced, generating a long‐period or irregular chaotic oscillation. This paper discusses these phenomena. the limiting set is determined by iteratively applying Poincaré mapping to the inputoutput characteristic. the stability is discussed using the Lyapunov exponent. It is shown as a conclusion that the number of invertor stages composing the GaAs ring oscillator should be as large a prime number as possible, as long as the oscillating condition is satisfied.
Abnormal signal detection and cancellation by using adaptive digital filter
Authors: Matsui Minoru , Hagiwara Masafumi , Nakagawa Masao , Hayashi Yasuhito
Published: July 2007

Recently, the detection of a noise component added in a transmission line and a signal component buried in a noise have become important problems. an adaptive predictor using an adaptive digital filter (ADF) is effective in cancelling the noise component in the input signal, especially when the statistical property of the noise is unknown. In addition, it can operate at high speed because of its simplicity. the conventional adaptive predictor using ADF can detect the existence of an abnormal signal. However, it cannot detect its accurate waveform because of an occurrence of echo caused by the abnormal signal. Therefore, the conventional system cannot cancel the abnormal signal.

In this paper, a novel system is proposed to cancel an abnormal signal in an input signal by using an adaptive predictor with a decision feedback. First, the cause of the occurrence of echo in the conventional predictor is shown. Next, the behavior of the new system is explained. Then a more accurate canceller of the abnormal signal with the two cascade‐connected ADFs is shown.
Uniform filter bank containing N‐path digital filter
Authors: Ikehara Masaaki , Takahashi Shinichi
Published: July 2007

This paper presents a construction method of a uniform filter bank using anN‐ path digital network. This filter bank is constructed by connecting anN‐path digital network to DFT polyphase filter banks. First, the input signal is divided into two parts by anN‐path digital network and its complement. These resulting output signals are separately band‐split and synthesized by DFT polyphase filter banks. Hence, its design method becomes very simple and both the required order and the number of multi plications can be reduced. Also, there quired structure is not so complicated.

Further, a design method of the low‐ pass digital filter using this digital filter bank is presented. the low‐pass filter with cutoff near π/2 which cannot be obtained easily in the usual multirate digital filter, can be realized by using these filter banks.
A method to reduce the circuit scale for systolic arrays and its application to reed‐solomon codecs
Authors: Iwamura Keiichi , Imai Hideki , Dohi Yasunori
Published: July 2007

The systolic array is a scheme for parallel processing and provides an architecture which is suited to a high‐speed operation. Consequently, the systolic array has been applied to the system for which the high‐speed processing is required, but not to the system for which the reduction of the circuit scale is required. This paper demonstrates that the principle of the systolic array can be applied as a means of reducing the circuit scale. By the proposed method, the circuit scale can be reduced in the system based on the systolic array, without an appreciable modification of the connection in the array and the control. This paper discusses the Reed‐Solomon (RS) coder‐decoder based on the systolic array as an example, and shows that the circuit scale can be reduced simply. By this system, the RS coder‐decoder can be realized in a simple way by the small circuit scale, corresponding to the processing speed of the system.
Ordering properties for multiple‐choice questionnaire items
Authors: Takeya Makoto
Published: July 2007

The multiple‐choice questionnaire is used frequently in psychological investigations of human behavior. Previously the author has proposed SS (semantic structure) analysis. The method is based on the order of the questionnaire items, and the structurization of the items is considered using the asymmetrical measure called ordering coefficient, which is a quantitative representation of the order of the items. The multiple‐choice questionnaire can roughly be divided into the following three kinds: (1) Type I data, which are evaluation measure data where the score is high when the evaluation is high; (2) Type II data, which are evaluation measure data where the score is the highest at the central value of the evaluation and lower at both sides; (3) Type III data, which are a nominal measure data where the score does not have a particular meaning. Semantic structure analysis which was reported previously, is concerned with Type I data. With that method as the background, this paper newly proposes the ordering coefficient, which can be applied also to Type II and Type III data. Then the effective category number is proposed as an index representing the statistical property of the answer distribution. It is shown that the sequence reference of the ordered structure based on the ordering coefficient is the second‐order moment around the central value in Type II data, and is the effective category number in Type III data. Finally, the usefulness of the structurization methods is investigated and possible applications are discussed.
Relationship between acceleration factor of weibull‐type lifetime distribution and proportional hazard model
Authors: Shiomi Hiroshi
Published: July 2007

Based on the knowledge concerning the life test for Weibull distribution, this paper considers the regression model for the reliability proposed by Cox et al., especially the proportional hazard model assuming Weibull distribution. Also discussed are the properties of the functiongterm representing the effect of factorxother than timet.

First, the relation between the regression expression for thegterm and the reaction rate model is presented. It is shown that thegterm corresponds to the failure rate acceleration factor in the accelerated life test, and is related directly to the lifetime acceleration factor as well as other acceleration factors for the reliability parameters.

An analogy is made between the expression that the reliability at the reference state to the power ofgis equal to the reliability in the accelerated state, and the weakest link model forglinks. Based on that analogy, it is shown that the reliability in the accelerated state is equivalent to the reliability of the series structure ofgindependent components with the reliability at the reference state. Thus,gcan be integrated as an acceleration factor representing a kind of scaling effect. It is shown also thatgcan be considered in the high‐reliability range as a reduction factor for the number of samples required to ensure reliability.
A study on finite wordlength effects in FIR digital echo cancellers using learning identification algorithm
Authors: Yasukawa Hiroshi , Ara Youjirou
Published: July 2007

Finite wordlength effects on the steady‐state characteristics of finite impulse response adaptive digital echo cancellers are considered. Focusing on an FIR‐type echo canceller based on the learning identification algorithm, the so‐called normalized least mean square algorithm was investigated. Both fixed point and floating point arithmetic systems are discussed. The equivalent noise models for both systems are given, and the output errors caused by quantization and rounding noises were analyzed to allow explicit representation of echo canceller parameters (particularly wordlength) when the input signal is white Gaussian.

Further, the relationship between echo cancellation and circuit parameters such as number of filter tap, loop‐gain coefficient, etc., the optimal parameter values to minimize output error are also discussed. Computer simulation results were compared with the analytical values and found to be in good agreement. The proposed method is valid for obtaining the performance of echo cancellers.
Evaluation of the smoothed group delay spectrum distance measure for speaker‐dependent speech recognition
Authors: Umezaki Taizo , Itakura Fumitada
Published: July 2007

This paper evaluates first the smoothed group delay spectrum (SGDS) distance measure through the isolated work speech recognition experiment by specified speakers. The experiment was performed for the following three cases, considering the speech recognition in the actual environment: 1) the case where the channels have difference characteristics; 2) the case where a white noise is added to the input speech; and 3) the case where the telephone speech is used as the input.

In all three cases, the recognition rate is improved drastically compared to the traditional LPC cepstrum distance measure. An improvement of the recognition rate by 16 percent was realized under the noise of segmental SN ratio 20 dB. Then the distance measure is evaluated for the case where the FFT cepstrum is converted into the group delay spectrum.

The proposed method gives a better recognition rate compared to the conventional FFT cepstrum distance measure, but the result is worse than the SGDA measure by approximately 3 percent since the higher‐order FFT cepstrum coefficient has a larger variance on the time axis.

Finally, the SGDS distance measure is evaluated by the isolated word speech recognition system with the monosyllable as the registered speech. The vowel recognition rate is improved, which improved the recognition rates for the syllable and the word by 2 percent or more on a relative scale.
Trapped‐energy piezoelectric resonators with elliptical ring electrodes
Authors: Nakamura Kiyoshi , Yasuike Ryoichi , Shimizu Hiroshi
Published: July 2007

This paper proposes and investigates the characteristics of trapped‐energy piezoelectric resonators with elliptical ring electrodes conforming to anisotropies in the piezoelectric substrate. In such piezoelectric resonators, the electrode area can be enlarged without changing its single resonance characteristics. Therefore, the resonator has a low equivalent resistance. Moreover, to check the suitability of the elliptical ring electrodes for the proposed application, some resonators were fabricated using ceramic and AT‐cut quartz plates.

It is shown that lower equivalent resistance is obtained in this case compared to the conventional circular electrode resonators. Also, through the experiment it is shown that by allowing a few anharmonic overtones to appear, an AT‐cut quartz 3rd‐overtone resonator with a low equivalent resistance of ten‐odd Ohms can be realized.
A complex digital filter with asymmetrical frequency response based on imaginary resistance
Authors: Takahashi Akira , Nagai Nobuo , Miki Nobuhiro
Published: July 2007

A new frequency transformation is introduced by incorporating imaginary resistances into transmission line filters. Asymmetrical complex bandpass responses are derived from real low‐pass prototypes while the magnitude ripples are unchanged. The transformation is applied to designs of IIR digital filters with different inclinations on the upper and the lower transition band. The overall design is completed without iteration. As for a low‐pass to bandpass transformation based on a real function, the inclinations of the transition bands depend to the passband allocation. Crystal et al. [1] considered a simple shifting transformation to derive complex digital filters and Belevitch [4] examined a similar method for lumped constant networks. The upper and the lower transition band of such a filter become tunable but they are restricted to be symmetrical. By contrast, the proposed method enables highly flexible specifications. A design example is shown.
Output roundoff error in block realization of state‐space digital filters
Authors: Oguro Yoshinari , Yoshikawa Toshinori
Published: July 2007

This paper presents the analysis of the roundoff error due to product quantization for the block state‐space digital filter implemented with a digital signal processor (DSP) or a special‐purpose LSI for filtering in one dimension (1‐D) and two dimension (2‐D). Here, it is assumed that a special‐purpose LSI for filtering has two wordlengths, that is: 1) the external wordlength for the input signals, the output signals, the filter coefficients, and the state variables; and 2) the internal word‐length for the arithmetic logic unit (ALU) in that LSI. It is assumed also that the internal wordlength is longer than the external one.

Two numerical examples are illustrated for a 2‐D second‐order filter and a 2‐D (3, 3)‐th‐order filter. The results act as a guide to determine the internal word‐length and the external wordlength of a special‐purpose LSI. Moreover, by setting the internal wordlength a few bits longer than the external wordlength, the roundoff error of block filtering can be reduced to from 20 through 60 percent compared with the nonblock filtering.
M/G/1system with set‐up time for server replacement
Authors: Nishigaya Takashi , Mukumoto Kaiji , Fukuda Akira
Published: July 2007

This paper proposes anM/G/1queueing model in which the server is replaced by another one with different service time distribution when the number of customers in the system exceeds a threshold value.

A random set‐up time is needed to introduce the second server. This server works until the system becomes empty. This kind of system will appear, for instance, when the server is changed to a faster one as the number of waiting customers becomes too great.

In data communication systems, the set‐up time may correspond to the time until the new carrier frequency for the faster transmission speed becomes stable, the time needed to assign a new link and/or the time necessary to inform a partner of a change in line speed.

The behavior of the customers who receive the first and second kinds of service is analyzed using the theory of finite Markov chain and the decomposition property of theM/G/1system with server vacations, respectively. Important performance measures, such as the distribution and average of the number of customers in the system and their average time in the system, are obtained. The influence of server characteristics, the conditions under which the server is replaced, and the distribution of set‐up time on the performance of the system are clarified.
Image processing by two‐dimensional recursive filters using the fornasini‐marchesini model
Authors: Hinamoto Takao , Muneyasu Mitsuji
Published: July 2007

This paper considers a simple two‐dimensional (2‐D) IIR filter based on the Fornasini‐Marchesini local state‐space (LSS) model. It is shown that if image processing is carried out using such filters from four directions, smoothing, edge detection or edge enhancement can be achieved without any distortion. The proposed technique allows one to flexibly perform the forementioned filtering by choosing three parameters. Moreover, filter analysis including stability is easy due to using a well‐known 2‐D LSS model. Finally, some examples are given to illustrate the utility of the proposed technique.
A multifeedback active circuit compensating effects of operational amplifier finite GB product and input capacitance
Authors: Okine Mitsuo , Fujii Nobuo
Published: July 2007

Multifeedback active circuits are simpler and have low element sensitivity for passive elements; and since they can easily be compensated to operate at higher frequencies, they are among the useful circuits for basic biquad section.

Various high‐frequency compensation techniques have been reported which compensate for the finite GB product of an operational amplifier by the passive circuit, but the circuit design should consider the effect of input capacitance.

This paper proposes a multifeedback active circuit in which high‐frequency operation can be obtained by compensating the effect of finite GB product and input capacitance of the operational amplifier. The proposed circuit is studied to obtain the pole sensitivity with respect to the GB product.

The spread of circuit element values and the influence of the secondary pole of the operational amplifier are discussed, and the compensation for the circuit is proposed. Finally, a fifth‐order lowpass filter with f0 = 100 kHz and passband ripple of 0.1 dB is designed, and its operation is confirmed through experiment.
An adaptive algorithm of a logarithmic‐type adaptive digital filter based on the LMS/Newton method
Authors: Kobayashi Masaki , Itoh Yoshio , Mikami Naoki , Kusaka Hiroji
Published: July 2007

The logarithmic adaptive digital filter (ADF) estimates the unknown system in which the transfer function is represented by a rational function of z. It consists of an ADF to estimate the logarithm of the denominator polynomial of the transfer function and a transversal ADF to estimate the numerator polynomial. Compared to the conventional transversal ADF, it is known that the number of taps can be reduced in this kind of ADF.

Studies have been made concerning the adaptive algorithm of the logarithmic ADF and the convergence condition. A problem is that the correlation matrix is a function of the input and the output signals of ADF. This increases the convergence time, compared to the transversal ADF, when the input signal is white.

This paper discusses the method of the improvement of the convergence speed and proposes the adaptive algorithm for the logarithmic ADF based on the LMS/Newton method. The successive computation of the inverse matrix of the correlation matrix (Jacobian) as well as the adaptive algorithm are derived. In contrast to the algorithm for the transversal ADF, it is shown that the square term of the estimation error is included in the update term of the tap vector.

Finally, the convergence condition for the proposed algorithm is derived. The convergence speed, the adaptive algorithm and the convergence condition are examined by a computer simulation.
Use of a laplace‐transform relaxation method for the analysis of nonlinear electric circuits
Authors: Ichikawa Satoshi , Tada Hideo
Published: July 2007

The relaxation method is one of the methods for solving an initial value problem for a set of differential equations and is suitable for analysis of large‐scale circuits such as those simulating VLSI circuits. In analysis of the relaxation method, time domain analysis is most common but complex frequency domain analysis by means of the Laplace transform also is applicable.

This paper presents the Laplace‐transform analysis. Semiconducting elements such as transistors of the VLSI circuits exhibit nonlinear characteristics. Thus, the differential equations to be used in the relaxation method must be nonlinear. In some cases, the properties of nonlinear elements are given not by analytic functions but by a series of discrete numerical values such as observed data. To express the nonlinearity of these elements, multidimensional interpolation formulas are used in this paper and practical computer algorithms for solving them are derived. The analysis of the conditions of convergence of the relaxation method shows that the proposed algorithm is applicable to circuits which operate in both stable and unstable domain, such as oscillators.
Identity‐based noninteractive common‐key generation and its application to cryptosystems
Authors: Tanaka Hatsukazu
Published: July 2007

At Crypto '84, Shamir originally proposed the concept of identity (ID)‐based cryptosystems and signature schemes. In this paper, a new realization scheme of a cryptosystem based on this concept is proposed for which the common‐key generation based on ID‐information requires neither a public directory nor interactive preparation for communication.

For the principal operations of common‐key generation it is necessary to compute powers of integers modulo the product of two large Sophie Germain (SG) primes. The basis for security, as in the RSA cryptosystem, depends on the computational difficulty of factoring this product into its constituent primes. In particular, as a realization of a cryptosystem of the new ID‐based type, we permit the generation of nonsymmetric common keys and generate two different common keys for each pair of users. One key is used for enciphering and the other is used for deciphering when they are applied to a common‐key cryptosystem. The result is a very secure realization of an ID‐based cryptosystem which prevents both the disclosure of the center's secrets and a conspiracy by nonparticipants to forge a secret key between users since the exponent is nonsymmetric in the step before executing the exponentiation and it is a proper value between two users.
Extraction of symmetry properties using correlation with rotated and reflected images
Authors: Masuda Takeshi , Yamamoto Kazuhiko , Yamada Hiromitsu
Published: July 2007

The symmetrical properties of an image or a figure are important in visual psychology and computer vision.

This paper proposes a new method to extract the properties of rotational symmetry and reflectional symmetry from planar two‐dimensional images. In the detection of the rotational symmetry, first, the original image for a quantized range of angles of rotation is rotated. The rotated results are convolved with the image using directional features. Then a set of affine transformations is applied to the parameter space to obtain the correlation results using each pixel as the center of rotation.

The periodicity of the correlation along the rotation angle for each point is evaluated. Finally, the local maximum correlation is determined that indicates the center and the number of folds of the rotational symmetry. In the detection of the reflectional symmetry, the image for the lines in the possible quantized directions is reflected. Then the correlation between the resulting images and the original image is calculated.

The transformation that maximizes the correlation directly indicates the direction of the axis of the reflectional symmetry and the translation amount of the glide symmetry. This method does not require any segmentation nor knowledge of the centroid position.

The method in this paper evaluates the transformation that matches the images even though the match is a partial one; thus, it can extract the symmetrical property that exists only partially.

Although a large amount of computation and storage capacity is required, the method is fundamental, versatile, and suited to the parallel computation.
A timing analyzer for multiple clock phase designs with level‐sensitive latch feedback loops
Authors: Imai Masanori , Ishikawa Hiromi , Kobara Junko
Published: July 2007

This paper proposes a method for the high‐speed timing analysis of the multiple clock phase synchronized circuit. In general, the static timing analysis can be executed by the computational complexity which is independent of the input pattern.

In the traditional method of handling the multiple clock phase synchronized circuit, however, the timing analysis of the circuit requires the number of periods, which depends on the circuit structure, such as the number of latch stages in the longest path in the circuit. In addition, independently of whether or not there exists a loop containing a latch, the same number of elements as that of the clock phases must be examined in a period.

A larger number of processings is always required when there exists a loop. By contrast, in the proposed method, each element is examining exactly once, if there does not exist a loop. Even if there exists a loop, the processing can be executed by the number which is independent of the number of phases. The number is several in the typical practical circuit. Thus, the speed is improved by the proposed method by restricting the timing analysis over multiple phases and multiple periods into a single period (the proposed timing analysis in a period, in the sense of this paper, is of a multiplexed nature since the verification extends over multiple phases and multiple periods).
Periodic sampling basis and associated biorthonormal basis of signal spaces composed of spline functions
Authors: Toraichi Kazuo , Iwaki Mamoru
Published: July 2007

This paper derives a Fourier‐like expansion formula in the signal space composed of spline functions, with the sampled value sequence of the signal as the expansion coefficients. Here, the domain is a finite closed interval and the boundary condition is periodic. The signal space composed of spline functions is one of the generalizations of the band‐limited signal space with the continuous differentiability as the parameter. Consequently, the Fourier‐like expansion formula derived in this paper is a generalization of Cahn's sampling theorem in the band‐limited signal space.
Uniform wiring structure embeddable in euclidean space
Authors: Aso Hirotomo
Published: July 2007

In a systolic array, uniform wiring is required for simplification of processor elements, synchronous and parallel data transmission through communications links, etc. As a method for designing a systolic array for a loop program given as a problem specification, there exists a method which is based on extracting wiring information from dependence relations among elemental computations in the loop program. In this paper, the uniformity of wiring structure is logically defined and a sufficient condition is given under with a given uniform wiring structure is embedded in a Euclidean space. In addition, its implementation method is given in the form of an embedding map. Examples satisfying this condition and a counterexample related to this condition are given. Furthermore, it is shown that there are cases that are embeddable in a Euclidean space even if they do not satisfy the given sufficient condition, which implies a natural expansion of the definition of embedding.
Application of K—M algorithm to vector quantization
Authors: Yuasa Tetsuya , Arimoto Suguru
Published: July 2007

This paper considers applying the algorithm proposed by Kalantari and McDonald (called the K—M algorithm) [1] for solving the nearest point problem to vector quantization. As a high‐performance vector quantization, the LBG algorithm in which a representative vector is defined as the center of gravity of a segment is well known. However, the method has a problem due to its inherent property that the optimal segmentation is not always attained, which implies a possibility that important information may be lost. By contrast, the proposed method is based on the K—M algorithm and restores the original signal within a specified quantization error ϵ. Consequently, the problem of information loss is avoided by defining ϵ appropriately. A simulation is executed for four‐dimensional quantization with regard to the memoryless Gaussian information source, and a satisfactory result is obtained from the viewpoint of the rate‐distortion theory.
A method for synthesizing animation to transmit sign language by intelligent communication
Authors: Xu Jun , Aoki Yoshinao , Zheng Zhong
Published: July 2007

The following intelligent communication system is considered for the transmission of the animation image information. The structural models are prepared both at the transmitter and the receiver. Only the information concerning the motion of the object is transmitted to provide the model with the motion parameters, and the animation image is synthesized. In such a system, the real‐time image synthesis based on the motion parameters is required.

This paper aims at the intelligent communication of the sign language image using a personal computer. A method of real‐time synthesis is discussed which is based on the parameter representation of the hand motion and the computer graphics (CG) of the animation image. When the animation image for the human body is to be generated in real‐time, using the three‐dimensional shape model, the real‐time system is difficult to realize at the present stage by a personal computer from the viewpoint of the computation time. An idea is to use the key‐frame figure interpolation (which is a two‐dimensional figure processing) instead of the three‐dimensional shape model to reduce the computation time in generating the animation. However, it is difficult in this method to derive the rotational image of a three‐dimensional object such as the human hand.

From such a viewpoint, the stick‐figure model for the upper limb is adopted in this study, aiming at the intelligent transmission of the sign language image. The state of connection of the three‐dimensional segments, which are obtained by the segmentation at the joints, is represented by a vector. The skeleton represented by the vector is shaped appropriately into a geometrical shape. Then, using the three‐dimensional vector representing the skeleton motion, the shapes of the figure, etc., are constructed and the result is projected on the two‐dimensional plane.
A method for two‐dimensional layout of semantic structure graphs
Authors: Matsui Tatsunori
Published: July 2007

A questionnaire containing multiple‐choice questions is a representative method to investigate human behavior. Previously, Takeya proposed the semantic structure analysis (SS analysis) as an analytical means for data obtained by the forementioned method. A structural graph of the SS analysis is called an SS graph, and it is conceived that the SS graph is of the hierarchical structure when items are laid out taking the ordinate for the measurement as the statistic such as mean evaluation values. However, no argument has been made with the layout of the abscissa.

With this in mind, an observation concerning the unsolved problem, i.e., a method for two‐dimensional layout of the semantic structure graph, is given in this paper. To solve this problem, a concept of a zone is introduced from a relationship between the ordering coefficient and the factor load by means of the centroid method. Then a measure to compose the abscissa by means of the zone determination values is proposed.

It is shown that not only can the relationship among the individual items be comprehended but also the meanings grasped as item groups together with the meanings among the item groups. Furthermore, by observing the linkage of the amount of information possessed by the individual items, especially of the effective category numbers and mean evaluation values, by means of a model and examples, the size of scattering of the evaluation values is explained explicitly by composing the abscissa by means of this effective category number. Thus, the relationship of items including the response pattern can be grasped.
An adaptive lattice filter using a cyclic enzyme system
Authors: Iiguni Youji
Published: July 2007

An adaptive lattice filter for filtering impulsive noise is designed using a cyclic enzyme system. The cyclic enzyme system has a memory mechanism and can maintain the previous output for some duration independently of the system input. The partial autocorrelation (PARCOR) coefficient computed through the system is then robust against impulsive noise that appears as large spikes of short duration. Furthermore, a set of PARCOR coefficients estimated by the new filter is always stable. The effectiveness is investigated analytically and through computer simulation.
A method for transforming multiple‐objective linear programming problems with trapezoidal Fuzzy coefficients
Authors: Okada Shinkoh , Nakahara Yozo , Ida Kenichi , Gen Mitsuo
Published: July 2007

Recently, many methods have been reported for transforming fuzzy multiple‐objective linear programming (MOLP) problems. However, the transformation into a crisp MOLP problem requires an extremely large number of constraints and decision variables which is the main disadvantage of these approaches.

This paper proposes that a maximizing MOLP problem with trapezoidal positive fuzzy coefficients can be transformed into a crisp MOLP problem without increasing the number of constraints by basing the two indices on the inequality relation between trapezoidal fuzzy numbers. The usefulness of the proposed method is demonstrated.
Algebraic geometric codes on certain plane curves
Authors: Miura Shinji
Published: July 2007

Necessary and sufficient conditions are given for projective plane curves to have cusps isomorphic to the origin of an affine plane curve xa + yb. Based on them, a family of curves Cab having only one such cusp as a singular point and a family of curves rCab having only two such cusps as singular points are formulated. Also, the structures of algebraic geometric codes generated on curves contained in these families are shown, where a and b are relatively prime. Then the genus is (a − 1)/(b − 1)/2 and the basis of linear space L(m · P) is given by rational functions xiyi only. Second, by giving concrete examples, it is shown that families of curves Cab and rCab contain many curves which attain Hasse‐Weil upper bound.
On a burst error correcting algorithm for binary expanded reed‐solomon codes
Authors: Kohnosu Toshiyuki , Hirasawa Shigeichi , Nishijima Toshihisa
Published: July 2007

The Reed‐Solomon (RS) code is widely applied to various fields including digital memory and communications systems. Since it has desirable properties from various viewpoints, intensive studies are made on its performance such as error correction. The code is not a complete code although it is a maximum‐distance separation (MDS) code, and there is a possibility that the code can correct more errors than the bounded distance decoding. From such a standpoint, this paper presents a method which can fully utilize its potential power for burst error correction when (t + 1) symbol errors are detected on the binary expanded RS code. The property that each of the sequences obtained by dividing the RS code with a certain parameter according to the basis is a codeword of BCH code, and an algorithm is proposed which estimates the symbol containing the head or tail of the solid burst error by superposing the received sequences. A decoding method is obtained which completely guarantees the error‐correcting power realizable by the bounded distance decoding on GF(2m) and realizes a larger error‐correcting power than the bounded distance decoding for the solid burst error represented on GF(2). The proposed method is also applied to the correction of the high‐density burst error, and the usefulness is demonstrated.
Deficient SOCS3 expression in CD4+CD25+FoxP3+ regulatory T cells and SOCS3‐mediated suppression of Treg function
Authors: Pillemer Brendan B. L. , Xu Hui , Oriss Timothy B. , Qi Zengbiao , Ray Anuradha
Published: July 2007

Naturally occurring CD4+CD25+FoxP3+ regulatory T cells (Treg) suppress T helper (Th) cell‐mediated immune responses. The cytokines IL‐2 and IL‐6 are known to influence Treg function. However, their relative effects on Th cells versus Treg are not well understood. Stimulation with IL‐2, and to a lesser extent, IL‐6, enhanced Treg proliferation, FoxP3 and CTLA4 maintenance, and suppressive function. In contrast, when IL‐2 or IL‐6 were added to Treg/Th cell cocultures, suppression was inhibited. The molecule SOCS3 negatively regulates responses to IL‐2 and IL‐6. Interestingly, unlike Th cells, Treg were found to be deficient in SOCS3 protein expression. The significance of this finding lies in the need for Treg to rapidly respond to these cytokines to prevent unwarranted immune responses to self‐antigens. Overexpression of SOCS3 in Treg decreased their proliferation, FoxP3 and CTLA‐4 expression and suppressive function. Thus, up‐regulation of SOCS3 expression may be a useful therapeutic approach in diseases where inhibition of Treg is desirable.
Synthesis of a Norsesquiterpene Spirolactone/Steroidal Hybrid by Using an Environmentally Friendly Domino Reaction as a Key Step
Authors: Chanu Angéline , Safir Imad , Basak Ramkrishna , Chiaroni Angèle , Arseniyadis Siméon
Published: July 2007

A new class of hybrid molecules is accessed by elaborating testosterone's AB ring into the norsesquiterpene spirolactone A′B′ ring. The cyclic ene‐acetal 6b, obtained by a PhI(OAc)2‐mediated domino process from vicinal unsaturated diol 5, is used for the synthesis of a norsesquiterpene spirolactone/testosterone hybrid. The route presented combines the advantages of domino reactions with the ease of functional group interchange on steroidal frameworks. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Nontraditional Electrode Materials in Environmental Analysis of Biologically Active Organic Compounds
Authors: Barek Jiří , Fischer Jan , Navrátil Tomáš , Pecková Karolina , Yosypchuk Bogdan , Zima Jiří
Published: July 2007

This review describes recent results regarding voltammetric and amperometric determination of submicromolar concentrations of various environmentally important biologically active organic substances using nontraditional types of electrodes either in batch analysis or in flow liquid systems (especially HPLC or FIA with electrochemical detection). Attention is paid to solid amalgam electrodes (environmentally friendly alternatives to mercury electrodes), to carbon paste electrodes with easily renewable surface, to boron doped diamond film electrodes with very low noise and broad potential window, and to inexpensive solid composite electrodes with high signal‐to‐noise ratio, compatibility with organic solvents and easy mechanical or electrochemical pretreatment. The review concentrates on our own results in the context of the general development in the filed.