bluuebunny/crossref_metadata_2025 huggingface dataset:
Hoch effiziente asymmetrische Katalyse durch doppelte Aktivierung von Nucleophil und Elektrophil
Authors: Ma Jun‐An , Cahard Dominique
Published: September 2004

Die Entwicklung neuer Hochleistungs‐Katalysatoren für asymmetrische Katalysereaktionen ist für die Organische Chemie von dauerhaftem Interesse. Eine aktuelle Methode bei der stereoselektiven Synthese ist die Verwendung einer Kombination von Lewis‐Säure und Lewis‐Base. Der Synergieeffekt durch die Aktivierung mithilfe von zwei oder mehr reaktiven Zentren führt zu hohen Reaktionsgeschwindigkeiten und zu einer hervorragenden Übertragung der stereochemischen Information. Obwohl durch die unerwünschte Reaktion der Lewis‐Säure mit der Lewis‐Base der Katalysator inaktiviert werden kann, wird das Konzept der doppelten Aktivierung mit großem Aufwand weiterentwickelt. Das Ziel ist die Herstellung biomimetischer Katalysesysteme auf der Grundlage enzymatischer Prozesse mit cokatalytischen Metallionen. Doppelt aktivierende Katalysatorsysteme erweitern die Zahl bereits bekannter Katalysatoren beträchtlich. Die effektivsten dieser Systeme werden in diesem Aufsatz erörtert und die Wirkungsmechanismen diskutiert.
Katalytische Carbonylierungen: kein Bedarf an Kohlenmonoxid
Authors: Morimoto Tsumoru , Kakiuchi Kiyomi
Published: September 2004

Erste bahnbrechende Erfolge in der metallorganischen Katalyse gelangen mit der Entdeckung der Roelen‐Reaktion 1938 (Hydroformylierung mit Kohlenmonoxid und Wasserstoff) und der Reppe‐Reaktion 1939 (Hydrocarboxylierung mit Kohlenmonoxid und Wasser). Seither haben Carbonylierungen mit Kohlenmonoxid einen festen Platz in der metallorganischen Chemie und der organischen Synthese. Allerdings ist die Verwendung von gasförmigem Kohlenmonoxid problematisch (toxisches Treibhausgas), sodass in neuerer Zeit Strategien zur Verwendung anderer Carbonylierungsreagentien entwickelt wurden. Dieser Kurzaufsatz beschreibt Carbonylierungen, die ohne direkten Einsatz von Kohlenmonoxid durchgeführt werden können.
Der Begriff “Dimensionalität” in der Analytischen Chemie – Grundlagen und Anwendungen
Authors: Danzer Klaus
Published: September 2004

Der Begriff Dimensionalität wird in der Analytischen Chemie mit unterschiedlicher Bedeutung verwendet. So sprechen Analytiker von zweidimensionalen Analysenmethoden, z. B. der 2D‐NMR‐Spektroskopie oder der 2D‐Dünnschichtchromatographie, von zweidimensionalen oder dreidimensionalen analytischen Informationen,1 von zweidimensionalen oder dreidimensionalen Bildern in der Oberflächenanalytik sowie von m‐dimensionalen Analysendaten,2 die beispielsweise als Resultat von Mehrkomponentenanalysen erhalten werden. Diese Beispiele belegen, dass der Begriff Dimensionalität gegenwärtig teilweise widersprüchlich verwendet wird. Diese verwirrende Situation trägt nicht zu einem einheitlichen Verständnis des Begriffs Dimensionalität in der Analytischen Chemie bei. Es ist deshalb das Anliegen dieses Dokuments, ein Konzept für die Verwendung des Begriffs Dimensionalität in der Analytischen Chemie vorzustellen.
Titelbild: Total Synthesis and Configurational Assignment of (−)‐Dictyostatin, a Microtubule‐Stabilizing Macrolide of Marine Sponge Origin / Total Synthesis of (−)‐Dictyostatin: Confirmation of Relative and Absolute Configurations (Angew. Chem. 35/2004)
Authors: Paterson Ian , Britton Robert , Delgado Oscar , Meyer Arndt , Poullennec Karine G. , Shin Youseung , Fournier Jean‐Hugues , Fukui Yoshikazu , Brückner Arndt M. , Curran Dennis P.
Published: September 2004

Aus dem Meeresschwamm Corallistidae stammt (−)‐Dictyostatin, ein Tubuli‐stabilisierender Naturstoff, der gegen multiresistente Tumore wirksam sein könnte. Paterson et al. und Curran et al. beschreiben in ihren Zuschriften auf S. 4729 ff. und S. 4734 ff. die Totalsynthese dieser schwierigen Zielverbindung. Da die relative und absolute Konfiguration des Makrolactons zweifelsfrei feststehen, können die Synthese größerer Mengen des Wirkstoffs und das gezielte Design von Analoga beginnen. (Das Photo des Schwamms wurde von der Harbor Branch Oceanographic Institution zur Verfügung gestellt.)
Cover Picture: Total Synthesis and Configurational Assignment of (−)‐Dictyostatin, a Microtubule‐Stabilizing Macrolide of Marine Sponge Origin / Total Synthesis of (−)‐Dictyostatin: Confirmation of Relative and Absolute Configurations (Angew. Chem. Int. Ed. 35/2004)
Authors: Paterson Ian , Britton Robert , Delgado Oscar , Meyer Arndt , Poullennec Karine G. , Shin Youseung , Fournier Jean‐Hugues , Fukui Yoshikazu , Brückner Arndt M. , Curran Dennis P.
Published: September 2004

Sponging off nature is a reliable way to find promising drug leads: (−)‐Dictyostatin, which was isolated from the marine sponge Corallistidae, is a novel microtubule‐stabilizing agent that could be useful against multidrug‐resistant tumors. In their Communications on pages 4629 ff. and 4634 ff., the groups of I. Paterson and D. P. Curran describe the total synthesis of this challenging target, thus establishing unequivocally the relative and absolute configuration of the macrolactone and opening the way to useful amounts of the drug and designed analogues. The Photo of the sponge was provided by Harbor Branch Oceanographic Institution.
Prognostic significance of serum osteoprotegerin levels in patients with bladder carcinoma
Authors: Mizutani Yoichi , Matsubara Hiroki , Yamamoto Kosuke , Nan Li Yong , Mikami Kazuya , Okihara Koji , Kawauchi Akihiro , Bonavida Benjamin , Miki Tsuneharu
Published: September 2004

BACKGROUND

Tumor necrosis factor–related apoptosis‐inducing ligand (TRAIL) plays an important role in the process of lymphocyte‐mediated cytotoxicity against malignant cells. Osteoprotegerin (OPG) is a soluble decoy receptor for TRAIL, and circulating OPG has been implicated in the protection of cells from TRAIL‐mediated apoptosis. Thus, OPG may protect tumor cells from lymphocyte‐mediated cytotoxicity and, as a result, contribute to tumor progression. In the current study, the authors investigated this hypothesis in patients with bladder carcinoma.

METHODS

Serum OPG levels for 185 patients with bladder carcinoma were determined using an enzyme‐linked immunosorbent assay. These levels then were assessed for potential correlations with various disease characteristics and outcome measures.

RESULTS

The mean serum OPG concentration in patients with bladder carcinoma was approximately 3 times greater than the mean concentration in healthy individuals, and among patients with bladder carcinoma, higher tumor stage and grade were found to be associated with increased serum OPG levels. Within the subpopulation of patients with superficial bladder carcinoma, after a follow‐up period of 5 years, those who had low serum OPG levels tended to have a longer postoperative tumor‐free interval compared with those who had high serum OPG levels. Furthermore, among patients with muscle‐invasive bladder carcinoma, the 5‐year disease‐specific survival rate was greater for those who had low serum OPG levels than for those who had high serum OPG levels.

CONCLUSIONS

To the authors' knowledge, the current study is the first to demonstrate that serum OPG concentration is correlated with both tumor stage and tumor grade and that elevated serum OPG levels are predictive of early recurrence in patients with bladder carcinoma. These findings suggest that serum OPG concentration may have utility as a prognostic parameter in this setting. Cancer 2004. © 2004 American Cancer Society.
Is routine triple endoscopy for head and neck carcinoma patients necessary in light of a negative chest computed tomography scan?
Authors: Guardiola Emmanuel , Pivot Xavier , Dassonville Olivier , Poissonnet Gilles , Marcy Pierre‐Yves , Otto Josiane , Poudenx Michel , Francois Eric , Bensadoun René‐Jean , Thyss Antoine , Demard François , Schneider Maurice
Published: September 2004

BACKGROUND

The objective of the current study was to analyze the results obtained by triple endoscopy during the initial evaluation of a primary carcinoma of the head and neck.

METHODS

A total of 487 patients with a squamous cell carcinoma of the head and neck was studied. None of the patients had evidence of metastasis or a second primary tumor on the thoracic computed tomography (CT) scan or chest X‐ray. All patients underwent a triple endoscopy including nasopharyngoscopy, laryngoscopy, pharyngoscopy, bronchoscopy, and esophagoscopy.

RESULTS

A synchronous primary invasive carcinoma of the lung and esophagus was diagnosed in 5 patients (1%) and 10 patients (2%), respectively. In addition, nine lesions were considered to be a regional extension of the primary tumor to the esophagus, and nine in situ carcinomas were observed. It is interesting to note that a significant correlation was found between the risk of a second synchronous esophageal carcinoma and the initial location of the primary head and neck carcinoma (P = 0.002, chi‐square test). Esophageal carcinoma was observed in 1.3% of the patients with an oropharyngeal tumor, 2% of the patients with a laryngeal tumor, none of the patients with a tumor of the oral cavity, and 9.2% of the patients with a hypopharyngeal tumor.

CONCLUSIONS

The role of bronchoscopy and esophagoscopy in the presence of a normal thoracic CT scan has been questioned because of the relatively low incidence of a second esophageal and/or lung primary tumor. Nonetheless, based on the same incidence criterion, it appears reasonable to schedule a routine esophagoscopy for those patients with a squamous cell carcinoma of the hypopharynx. Cancer 2004. © 2004 American Cancer Society.
Electronically steerable parasitic array radiator antenna
Authors: Ohira Takashi , Iigusa Kyouichi
Published: September 2004

The electronically steerable parasitic array radiator antenna consists of one feed radiating element and parasitic radiating elements placed in the near field of the active radiator. A beam is formed due to spatial electromagnetic field coupling among radiating elements. The radiation pattern is electronically controlled by means of the variable capacitance devices (varactors) loading the parasitic elements. Unlike a conventional phased array, only one transmitter and receiver are needed for system configuration. Therefore, adaptive beamforming of low dissipation power and low fabrication cost can be achieved. On the other hand, there is only one output port to observe the signal and the weights can be controlled indirectly via reactors instead of direct control. In addition, due to interelement mutual coupling and the parasitic element being directly connected to the reactive device, the linear adaptive array theory developed to date cannot be applied straightforward. In this paper, the configuration of this antenna, its operating principle and formulation, and its measurement method, control scheme, and applications to signal processing are presented. We describe a mathematical model to simulate the radio frequency behavior of the antenna, the equivalent weight vector used for formulation of the characteristics, the admittance matrix including varactors, the effective element length, the equivalent steering vector method, the method for effectively extending the variable range of the capacitance of the varactor, the reactance circuit to cancel nonlinear distortions, the method for calibration of varactors and radiation pattern by measurement of near field of the radiating element, the learning criteria used to control radiation patterns autonomously in adaptation to the electromagnetic environment, the reactance optimization algorithm, the concept of the reactance domain signal processing and the direction of arrival estimation based on such a process, and diversity reception and spatial correlation. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(10): 25–45, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20081
Improved transient and steady‐state performance of series resonant ZCS high‐frequency inverter‐coupled voltage multiplier converter with dual mode PFM control scheme
Authors: Chu Enhui , Gamage Laknath , Ishitobi Manabu , Hiraki Eiji , Nakaoka Mutsuo
Published: September 2004

A variety of switched‐mode high‐voltage DC power supplies using voltage‐fed‐type or current‐fed‐type high‐frequency transformer resonant inverters with MOS gate bipolar power transistors (IGBTs) have been recently developed for medical‐use X‐ray high power generators. In general, the high‐voltage high‐power X‐ray generator using voltage‐fed high‐frequency inverter with a high‐voltage transformer link has to meet some performances such as (i) short rising period in start transient of X‐ray tube voltage, (ii) no overshoot transient response in tube voltage, (iii) minimized voltage ripple in periodic steady‐state under extremely wide load variations and filament heater current fluctuation conditions of the X‐ray tube.

This paper presents two lossless inductor snubber‐assisted series resonant zero current soft switching high‐frequency inverters using a diode‐capacitor ladder‐type voltage multiplier called Cockcroft‐Walton circuit, which is effectively implemented for a high DC voltage X‐ray power generator. This DC high‐voltage generator which incorporates a pulse frequency modulated series resonant inverter using IGBT power module packages is based on the operation principle of zero current soft switching commutation scheme under discontinuous resonant current and continuous resonant current transition modes. This series capacitor compensated for transformer resonant power converter with a high‐frequency transformer‐linked voltage boost multiplier can efficiently work a novel selectively changed dual mode PFM control scheme in order to improve the start transient and steady‐state response characteristics and can completely achieve stable zero current soft switching commutation tube filament current dependent on wide load parameter setting values with the aid of two lossless inductor snubbers. It is proved on the basis of simulation and experimental results in which a simple and low cost control implementation based on selectively changed dual‐mode PFM for high‐voltage X‐ray DC‐DC power converter with a voltage multiplier strategy has some specified voltage pattern tracking voltage response performances under rapid rising time and no overshoot in start transient tube voltage as well as the minimized steady‐state voltage ripple in tube voltage. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(4): 60–72, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10345
Determination of direct and quadrature axis inductances of synchronous reluctance motors with allowance for cross saturation
Authors: Yamamoto Shu , Ara Takahiro
Published: September 2004

The d‐axis inductance of reluctance motor is affected by not only the d‐axis current but also the q‐axis current, because of cross magnetic saturation between the direct and quadrature axes. This situation is similar for the q‐axis inductance. The authors propose a method to determine the d‐axis inductance related to the d‐ and q‐axis currents and the q‐axis inductance related to the d‐ and q‐axis currents from a standstill test. This method involves the following four steps. First a rectangular‐wave voltage, alternated between plus and minus, is applied to the two armature winding terminals after breaking the rotor in the d‐axis position. Secondly, the voltage and current between the terminals are measured. Thirdly, the d‐axis inductance related with d‐axis current is calculated from the voltage and current. Finally, the process above is repeated when a DC current flows from the remaining armature terminal to neutral point terminal and the d‐inductance related to the d‐ and q‐axis currents is derived. A similar treatment applies when determining the q‐axis inductance related to the d‐ and q‐axis currents in the q‐axis rotor position. The method is implemented on a 1.1 kW–178 V–6.3 A‐4P–2200 min−1 flux barrier type reluctance motor. Results of load performance on a vector controlled reluctance motor measured by on‐load tests and calculated from the d‐ and q‐axis inductances obtained by the proposed method clearly demonstrate the validity of the proposed method. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(4): 52–59, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10377
Network centric approach to protection, control, and monitoring for power system
Authors: Sekiguchi Katsuhiko , Shirota Yoshihiro , Shimoo Manabu , Sugiura Hideaki , Kagami Toshiro , Nakamura Tadashi
Published: September 2004

Due to the explosion in use of the Internet, it is expected that a variety of services will be provided through the communication network in the near future. Protection and control systems using the latest communication and information technology also allow for innovative solution to a wide range of power system problems. This paper describes a network‐centric approach to protection, control, and monitoring systems. When the proposed “Network” devices, server, and browser can communicate with each other, they can share information which can enhance the overall protection and control of the power systems. The paper includes: overview of network devices, key technologies, protection and control applications, issues, and conclusion. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(4): 31–41, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20006
Combined carbon‐dioxide‐capturing high‐performance power generation system using a solid oxide fuel cell operating on pressurized fuel/air
Authors: Inui Yoshitaka , Ishida Taichi , Matsumae Tomohiro
Published: September 2004

The authors recently proposed a high‐performance combined carbon‐dioxide‐capturing power generation system using a solid oxide fuel cell (SOFC) and a closed‐cycle MHD generator, in which pure oxygen is used as the oxidant. This combined system makes the best use of the advantages of combustion with pure oxygen but fails to prevent the efficiency deterioration caused by high power demand for oxygen production. In the present study, the authors modified this previous system and proposed an improved combined carbon‐dioxide‐capturing power generation system using SOFC/MHD characterized by a higher overall thermal efficiency. In this system, pure oxygen is supplied only to the combustor to reduce the power required for the oxygen production, and pressurized air is used as the oxidant gas in the SOFC. The power saving amounts to about 5% of the thermal input, resulting in a very high total thermal efficiency of 67.53% (HHV) or 74.94% (LHV), which is considered to be the highest possible value of the overall thermal efficiency of carbon‐dioxide‐capturing systems. Advantages of the proposed system suggest that it is advisable to continue further research in this direction. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(4): 21–30, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20010
High‐resolution image reconstruction with displacement errors: A framelet approach
Authors: Chan Raymond H. , Riemenschneider Sherman D. , Shen Lixin , Shen Zuowei
Published: September 2004

High‐resolution image reconstruction arises in many applications, such as remote sensing, surveillance, and medical imaging. The Bose and Boo (1998) model can be viewed as the passage of the high‐resolution image through a blurring kernel built from the tensor product of a univariate low‐pass filter of the form [½ + ϵ, 1, …, 1, ½ − ϵ], where ϵ is the displacement error. When the numberLof low‐resolution sensors is even, tight‐frame symmetric framlet filters were constructed (Chan et al.,2004b) from this low‐pass filter using Ron and Shen's (1997) unitary extension principle. The framelet filters do not depend on ϵ, and hence the resulting algorithm reduces to that of the case where ϵ = 0. Furthermore, the framelet method works for symmetric boundary conditions. This greatly simplifies the algorithm. However, both the design of the tight framelets and extension to symmetric boundary are only for evenLand cannot, be applied to the case whenLis odd. In this article, we design tight framelets and derive a tight‐framelet algorithm with symmetric boundary conditions that work for both odd and evenL. An analysis of the convergence of the algorithms is also given. The details of the implementations of the algorithm are also given. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 14, 91–104, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20012
Single‐frame image super‐resolution using learned wavelet coefficients
Authors: Jiji C. V. , Joshi M. V. , Chaudhuri Subhasis
Published: September 2004

We propose a single‐frame, learning‐based super‐resolution restoration technique by using the wavelet domain to define a constraint on the solution. Wavelet coefficients at finer scales of the unknown high‐resolution image are learned from a set of high‐resolution training images and the learned image in the wavelet domain is used for further regularization while super‐resolving the picture. We use an appropriate smoothness prior with discontinuity preservation in addition to the wavelet‐based constraint to estimate the super‐resolved image. The smoothness term ensures the spatial correlation among the pixels, whereas the learning term chooses the best edges from the training set. Because this amounts to extrapolating the high‐frequency components, the proposed method does not suffer from oversmoothing effects. The results demonstrate the effectiveness of the proposed approach. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 14, 105–112, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20013
Target image enhancement using representative line in MR cholangiography images
Authors: Kobashi Syoji , Kondo Katsuya , Hata Yutaka
Published: September 2004

MR cholangiography (MRC) is a commonly used imaging method for diagnosing the pancreatic duct. This article proposes a novel method for enhancing medical images called target image enhancement using representative line (TIER), and its application to MRC images. Our method first finds the representative line (RL) of the pancreatic duct using a fuzzy if‐then rule. TIER presumes the approximate region of the pancreatic duct using the obtained RL, and then emphasizes the intensity in the approximate region. Therefore, our method does not require any segmentation procedures, which often may be hard work. We evaluated the ability to find the RL and to estimate the approximate region of the pancreatic duct by applying the proposed method to computer‐simulated data and MRI phantom data. We also show the image‐enhanced images for normal and abnormal patients. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 14, 122–130, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20015
The use of super‐resolution techniques to reduce slice thickness in functional MRI
Authors: Peeters Ronald R. , Kornprobst Pierre , Nikolova Mila , Sunaert Stefan , Vieville Thierry , Malandain Grégoire , Deriche Rachid , Faugeras Olivier , Ng Michael , Van Hecke Paul
Published: September 2004

The problem of increasing the slice resolution of functional MRI (fMRI) images without a loss in signal‐to‐noise ratio is considered. In standard fMRI experiments, increasing the slice resolution by a certain factor decreases the signal‐to‐noise ratio of the images with the same factor. For this purpose an adapted EPI MRI acquisition protocol is proposed, allowing one to acquire slice‐shifted images from which one can generate interpolated super‐resolution images, with an increased resolution in the slice direction. To solve the problem of correctness and robustness of the created super‐resolution images from these slice‐shifted datasets, the use of discontinuity preserving regularization methods is proposed. Tests on real morphological, synthetic functional, and real functional MR datasets have been performed, by comparing the obtained super‐resolution datasets with high‐resolution reference datasets. In the morphological experiments the image spatial resolution of the different types of images are compared. In the synthetic and real fMRI experiments, on the other hand, the quality of the different datasets is studied as function of their resulting activation maps. From the results obtained in this study, we conclude that the proposed super‐resolution techniques can both improve the signal‐to‐noise ratio and augment the detectability of small activated areas in fMRI image sets acquired with thicker slices. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 14, 131–138, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20016
Pseudo‐random properties of self‐complementary symmetric graphs
Authors: Kisielewicz Andrzej , Peisert Wojciech
Published: September 2004

There are some results in the literature showing that Paley graphs behave in many ways like random graphs G(n, 1/2). In this paper, we extend these results to the other family of self‐complementary symmetric graphs. © 2004 Wiley Periodicals, Inc. J Graph Theory 47: 310–316, 2004
Antioxidant activity of Potentilla fruticosa
Authors: Miliauskas Giedrius , van Beek Teris A , Venskutonis Petras R , Linssen Jozef P H , de Waard Pieter , Sudhölter Ernst JR
Published: September 2004

The molecular structures of the radical scavenging compounds present in extracts of Potentilla fruticosa blossoms were elucidated and the antioxidant activities of various extracts were determined. The activities of the different fractions were monitored by off‐line and on‐line RP‐HPLC DPPH• and ABTS•+ scavenging methods. Twelve compounds were isolated and identified, namely ellagic acid, catechin, quercetin‐3‐β‐glucopyranoside, quercetin‐3‐β‐galactopyranoside, quercetin‐3‐β‐rutinoside, quercetin‐3‐β‐glucuronopyranoside, quercetin‐3‐α‐arabinofuranoside, kaempferol‐3‐β‐rutinoside, kaempferol‐3‐O‐β‐(6″‐O‐(E)‐p‐coumaroyl)glucopyranoside, rhamnetin‐3‐β‐glucopyranoside and rhamnetin‐3‐β‐galactopyranoside. The radical scavenging activity of each isolated compound was measured using DPPH• and ABTS•+ assays and compared with the activity of rosmarinic acid. Catechin and ellagic acid were found to be the most active radical scavengers. The antioxidant properties of plant fractions were assessed in model systems by measuring superoxide anion and hydrogen peroxide scavenging, β‐carotene bleaching, hexanal production in edible oil, peroxide formation, and the increase in UV absorbance in the course of oxidation. Copyright © 2004 Society of Chemical Industry
Comparison of matrix‐free acceleration techniques in compressible Navier–Stokes calculations
Authors: Marques N. P. C. , Pereira J. C. F.
Published: September 2004

Six different preconditioning methods to accelerate the convergence rate of Krylov‐subspace iterative methods are described, implemented and compared in the context of matrix‐free techniques. The acceleration techniques comprehend Krylov‐subspace iterative methods; invariant subspace‐based methods and matrix approximations: Jacobi, LU‐SGS, Deflated GMRES; Augmented GMRES; polynomial preconditioner and FGMRES/Krylov.

The relative behaviour of the methods is explained in terms of the spectral properties of the resulting iterative matrix. The employed code uses a Newton–Krylov approach to iteratively solve the Euler or Navier–Stokes equations, for a supersonic ramp or a viscous compressible double‐throat flow. The linear system approximate solver is the GMRES method, in either the restarted or FGMRES variants. The results show the better performance of the methods that approximate the iterative matrix, such as Jacobi, LU‐SGS and FGMRES/Krylov. Copyright © 2004 John Wiley & Sons, Ltd.
Central‐upwind schemes on triangular grids for hyperbolic systems of conservation laws
Authors: Kurganov Alexander , Petrova Guergana
Published: September 2004

We present a family of central‐upwind schemes on general triangular grids for solving two‐dimensional systems of conservation laws. The new schemes enjoy the main advantages of the Godunov‐type central schemes—simplicity, universality, and robustness and can be applied to problems with complicated geometries. The “triangular” central‐upwind schemes are based on the use of the directional local speeds of propagation and are a generalization of the central‐upwind schemes on rectangular grids, recently introduced in Kurganov et al. [SIAM J Sci Comput 23 (2001), 707–740]. We test a second‐order version of the proposed scheme on various examples. The main purpose of the numerical experiments is to demonstrate the potential of our method. The more universal “triangular” central‐upwind schemes provide the same high accuracy and resolution as the original, “rectangular” ones, and at the same time, they can be used to solve hyperbolic systems of conservation laws on complicated domains, where the implementation of triangular or mixed grids is advantageous. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
Operational performance of grid‐connected PV systems on buildings in Germany
Authors: Jahn Ulrike , Nasse Wolfgang
Published: September 2004

This paper presents operational performance results of grid‐connected PV systems in Germany, as collected and elaborated for the Photovoltaic Power Systems Programme (PVPS) of the International Energy Agency (IEA). Performance ratios obtained from 235 PV installations in Germany and from 133 PV plants in other countries are compared and discussed. For Germany, a significant rise in PV system performance and reliability was observed for new PV installations due to higher component efficiencies (e.g., inverter) and increased availabilities.

There is a lack of long‐term experience in performance and reliability of PV systems, owing to the absence of monitoring programmes. As an outcome of IEA PVPS collaborative work, Task 2 provides reliable and worldwide monitoring performance data and results (www.task2.org). Technical and operational data is available for system planning and comparison, for teaching and training purposes as well as for future developments of financing schemes (e.g., feed‐in‐tariffs) in order to stimulate the PV market. Copyright © 2004 John Wiley & Sons, Ltd.
Photovoltaics in an architectural context
Authors: Kaan Henk , Reijenga Tjerk
Published: September 2004

In well‐populated areas, such as western Europe, PV is often integrated into the building envelope. Despite the fact that there are many examples showing that PV can be an aesthetically neutral or visually attractive element in architecture, many BIPV systems display few architectural qualities. But if well applied, PV can increase a building's character and value. Within Task 7 of the IEA PVPS programme a team of experts with an architectural background studied which key requirements needed to be complied with (design criteria for good‐quality PV projects) in order to produce successful PV integration. These criteria are discussed in the article.

PV is not automatically considered an indispensable material in architectural terms. This is why, no matter how well it is integrated, PV remains an ‘added’ element. Architects can take this as their starting point and can use one of the design approaches that are presented in the article. These criteria for incorporating PV in the building design and the design criteria for good‐quality PV projects are important to architects and architectural critics in determining why a BIPV project, be it their own design or that of a colleague, is or is not aesthetically pleasing. This offers learning opportunities and reasons for follow‐up or improvement options. Architects who apply PV in a well‐thought‐out way can make their clients very happy, and thereby contribute to a greater acceptance of PV technology. Copyright © 2004 John Wiley & Sons, Ltd.
Electrotechnical requirements for PV on buildings
Authors: van Zolingen Ronald J. C.
Published: September 2004

World‐wide the number of grid‐connected PV systems is growing fast, especially in the built environment. In order to assure the quality and energy output of these systems, a number of electrotechnical requirements need to be fulfilled, at both component and system levels. In addition requirements with respect to electrical safety need to be met. Part of these requirements are covered by international standards, especially with respect to the PV modules. A number of standards is still under development. In the area of systems and utility interfacing local codes are still in use. These local codes differ significantly from country to country. Copyright © 2004 John Wiley & Sons, Ltd.
Progress in markets for grid‐connected PV systems in the built environment
Authors: Haas Reinhard
Published: September 2004

In the last decade of the 20th century a wide variety of promotion strategies increased the market penetration of small grid‐connected PV systems world‐wide. The objective of this paper is to assess the impact of these promotion strategies on the market for and on the economic performance of small grid‐connected PV systems. The most important conclusions of this analysis are:

Pure cost‐effectiveness is not crucial for private customers. Affordability is rather what counts.

Non‐monetary issues play an important role for a substantial increase in market deployment.

Comprehensive accompanied information and education activities are also important along with financial incentives.

There are still considerable barriers in the market: on the one hand transparent and competitive markets exist in only a few countries; on the other hand non‐monetary transaction costs still represent a major barrier.

Progress with respect to cost reduction has been achieved, but mainly for non‐module components. Copyright © 2004 John Wiley & Sons, Ltd.
Field experience with large‐scale implementation of domestic PV systems and with large PV systems on buildings in Japan
Authors: Otani Kenji , Kato Kazuhiko , Takashima Takumi , Yamaguchi Tetsuo , Sakuta Koichi
Published: September 2004

Under the auspices of the New Sunshine Program and continuous R&D programs by the New Energy Development and Industrial Technology Organization (NEDO), the authors have been implementing a measurement and evaluation program for photovoltaic (PV) systems since the fiscal year 1997. In this program, a total of 100 residential PV systems, equipped with special data acquisition systems, have been set up over seven years. The purpose of this study was to clarify the operating performance of the grid‐connected PV systems on the rooftops of residential houses in Japan and to develop a simulation methodology in order to estimate the electricity generation and costs in the actual housing environment. The validity of the simulation methodology was assessed by using the actually monitored data from some hundreds residential PV systems. Simulation results were also used to optimize the PV system design as well as to diagnose their operating conditions. The mean value of the final annual yield was around 1000 h; 975 h in 2000, 982 h in 2001 and 975 h in 2002, and the mean value of the performance ratio was over 70%; 73·3% in 2000, 71·8% in 2001 and 72·5% in 2001. Copyright © 2004 John Wiley & Sons, Ltd.
Examples of successful architectural integration of PV: Japan
Authors: Ohno Jiro
Published: September 2004

By the end of 2002 more than 1300 MWp of photovoltaic power was installed in industrialized countries worldwide. Of this, approximately 640 MWp, or 48%, is installed in Japan, mainly on buildings. This makes Japan the most prominent country in the field of building‐integrated photovoltaics (BIPV). The interest in integration of PV among Japanese architects has increased accordingly, which has resulted in many sophisticated and innovative designs. This short communication introduces four examples of successful architectural integration from different fields.

The Japanese government aims at an installed PV capacity of 4820 MWp in 2010. In parallel, the Japanese PV industry needs to develop into a strong sector which is able to operate without direct market support. The role of architects in this process should not only be to increase the volume of building integrated PV, but also to make comprehensive, integral designs, which include sunlight shading, thermal insulation, energy saving, passive use of solar energy, and obviously also photovoltaics. Furthermore, architects could make an important contribution to establishing a new, sustainable urban environment in which BIPV is used on a large scale as a distributed source of energy. This fits well within the new international effort in the framework of the International Energy Agency (IEA), Photovoltaic Power Systems (PVPS), Task 10. Copyright © 2004 John Wiley & Sons, Ltd.
A support system for software function discovery using histories of function executions
Authors: Morisaki Shuuji , Shiraishi Yumi , Yamato Masatake , Monden Akito , Matsumoto Ken‐ichi , Torii Koji
Published: September 2004

The majority of current application software packages have an extremely large number of functions because of the many different users envisioned for the software. This means that it is not easy for users to find useful functions. In this paper, the authors propose a system that supports the discovery of useful functions for users by allowing for shared referencing of function execution histories among users with similar uses for the software. The proposed system gathers a wide range of function execution histories over a long period of time, efficiently processes them, and then displays in a format that is easy to understand candidate functions that are unknown and useful to the user. The results of evaluation experiments using Microsoft Word 2000 and PowerPoint 2000 showed that an average of 63.7 functions were displayed as useful candidate functions to a total of nine subjects, with an average of 16.1 of them being unknown functions. In addition, the percentage of functions that users said were actually useful among the unknown functions discovered was 39.2% on average for Word and 46.3% on average for PowerPoint. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(12): 93–106, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10024
Application of genetic algorithm to flight schedule planning
Authors: Adachi Nobue , Sato Makihiko , Kobayashi Shigenobu
Published: September 2004

The authors developed a system that automatically creates regular aircraft flight schedules and minimizes the total number of aircraft required. Since the target problems are real‐world problems having constraints that are intertwined in a complex manner, the authors used a genetic algorithm to achieve the optimization. In this paper, the authors describe the problem setup and genetic algorithm configuration and verify the algorithm's effectiveness through experiments using real data. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(12): 83–92, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10036
Spoken dialogue processing method using inductive learning with genetic algorithm
Authors: Kimura Yasutomo , Araki Kenji , Momouchi Yoshio , Tochinai Koji
Published: September 2004

This paper describes a spoken dialogue processing, which includes the learning using spoken dialogue examples. Most of the spoken dialogue systems up to the present are task‐oriented, where the processing is based on the prespecified generation rules and database. It is then difficult to handle various topics, such as miscellaneous talks in daily dialogue. In the proposed method, the dialogue between the system and the user is processed as the spoken dialogue example, and the rule is acquired based on the pair of system response and user utterance, through inductive learning using the genetic algorithm. In other words, it is not necessary to prepare the training data beforehand, but the response is composed using the rules acquired from the actual dialogue examples. With this approach, the learning can be executed based on the dynamic data, and the deviation depending on the data is reduced. It is intended in this paper to examine the usefulness of the proposed method. Miscellaneous talks are considered. ELIZA‐type system, which is extended to the spoken dialogue, and the proposed method are compared through a comparison experiment and an experiment with multiple examinees. As a result, it is verified that the total ratio of the correct and almost correct responses is improved from 66.3% to 76.1%, and the effective responses can be constructed using the rules acquired from actual dialogue examples. This improvement of 9.8 points indicates that the proposed method is effective in handling miscellaneous talks. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(12): 67–82, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10204
Air transportation planning using neural networks as an example of the transportation squadron in the Japan Air Self‐Defense Force
Authors: Kurokawa Takakazu , Takeshita Ken
Published: September 2004

The task of a squadron at the Japan Air Self‐Defense Force (JASDF) is to transport personnel and materials, and the efficient operation of the squadron is a crucial issue in an emergency. However, transportation is planned manually at present, and it is difficult to quickly formulate an efficient plan. In this context, air transportation planning is considered a transport problem, and an air transportation planning method using a mutually coupled neural network composed of binary neurons, while considering the hardware implementation, is proposed. In the proposed neural network, air transportation planning is partitioned into three subproblems, which are successively solved by three neuron blocks. By this provision, the scale of the problem is reduced and the solution is derived efficiently. Several practical problems with various numbers of aircraft and transportation demands are considered, and simulations are performed using the neural network with various parameters. An examination of the results reveals that the proposed neural network is able to determine whether the air transportation planning can be performed with high speed and high accuracy. In other words, the proposed method is an efficient solution method with many advantages. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(12): 46–56, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10419
Generating derangements by interchanging at most four elements
Authors: Mikawa Kenji , Semba Ichiro
Published: September 2004

For the set S = {1,2,…,n}, a permutation π:S → S such that π(i)≠i is called a complete permutation, and the string π(1)π(2)…π(n) is called a derangement. In this paper, the authors consider the generation of a list that contains one instance of every derangement. Sequential generation, which sequentially generates a string by interchanging characters in the string, can generate the list more efficiently when fewer characters are interchanged. If 𝒫(S) denotes the list of derangements and deg(𝒫(S)) denotes the maximum value of the numbers of characters that are interchanged, no list of derangements such that deg(𝒫(S)) = O(1) is known as of today. In this paper, the authors notice that a derangement can be decomposed into mutually disjoint cycles to show that there exists no list of derangements such that deg(𝒫(S)) = 2. Also, in the second half of this paper, they consider an algorithm for generating a list for which deg(𝒫(S)) = 4 for |S|≥4. According to this algorithm, the average number of characters that are interchanged is roughly 2.980. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(12): 25–31, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10531
On the statistical properties of least‐square estimators of layered neural networks
Authors: Kitahara Masashi , Hayasaka Taichi , Toda Naohiro , Usui Shiro
Published: September 2004

There are still some statistical properties which have not been clarified in the regression model based on the three‐layered neural network. This paper presents an analysis of these problems, in terms of the probability distribution of the parameter estimators. It is first shown numerically that the least‐square estimator for the condition in which the probability distribution for the parameter estimator has not been clearly described follows a distribution which is different from the probability distribution derived in the past for various conditions. Based on the result, a theoretical analysis is presented for the simplified regression model, and it is shown that the least‐square parameter estimator follows the double‐exponential distribution. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(12): 1–9, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10580
Leaf trenching by Indian red admiral caterpillars for feeding and shelter construction
Authors: Ide Jun‐Ya
Published: September 2004

Many folivorous insects sever leaf veins, trench across leaf blades, or girdle petioles prior to feeding on leaves. The purpose of these behaviours is generally thought to be sabotage of the anti‐herbivore chemical defences of host plants. For insects that construct leaf shelters, these behaviours may make leaves easier to roll or fold. Larvae of the Indian red admiral butterfly, Vanessa indica (Herbst), cut trenches at the base of host plant leaves and construct leaf‐fold shelters. I attempted to determine which of the above functions the trenching behaviour of V. indica larvae serves. If the function of trenching is to facilitate leaf‐folding, then larvae should cut trenches before folding leaves. When the larvae used larger leaves, they tended to trench them prior to folding them. This suggests that the function of trenching behaviour is to make leaves easier to fold. However, larvae sometimes cut trenches after folding the leaves, suggesting that this behaviour has additional functions. When the larvae were about to moult or pupate, they did not cut trenches, suggesting that trenching behaviour may also be involved in feeding.
Harnack type estimates for nonlinear elliptic systems and applications
Authors: Busca Jérôme , Sirakov Boyan
Published: September 2004

In this paper we obtain a generalised maximum principle of Alexandrov–Bakelman–Pucci type for viscosity solutions of fully nonlinear cooperative elliptic systems. We also establish a Harnack estimate for such systems and give some applications. In particular, a Harnack type estimate for solutions of higher order equations is given.

Dans cet article nous obtenons un principe de maximum généralisé de type Alexandrov–Bakelman–Pucci pour les solutions de viscosité de systèmes elliptiques coopératifs complètement non-linéaires. Nous établissons une inégalité de Harnack pour ce type de systèmes et présentons quelques applications. En particulier, nous obtenons une inégalité de type Harnack pour les solutions d’équations polyharmoniques.
Multiplicity of positive solutions for an indefinite superlinear elliptic problem on RN
Authors: Du Yihong
Published: September 2004

We consider the elliptic problem

−Δu−λu=a(x)u^p

, with

p>1

and

a(x)

sign-changing. Under suitable conditions on

p

and

a(x)

, we extend the multiplicity, existence and nonexistence results known to hold for this equation on a bounded domain (with standard homogeneous boundary conditions) to the case that the bounded domain is replaced by the entire space

R^N

. More precisely, we show that there exists

Λ>0

such that this equation on

R^N

has no positive solution for

λ>Λ

, at least two positive solutions for

λ\in (0,Λ)

, and at least one positive solution for

λ\in (−∞,0]∪\{Λ\}

.

On considère le problème elliptique

−Δu−λu=a(x)u^p

, où

p>1

et

a(x)

change le signe. Sous des conditions adéquates sur

p

et

a(x)

, nous étendons les résultats connus sur la multiplicité, l’existence et la non-existence de cette équation sur un domaine borné (avec des conditions aux limites homogènes naturelles) où le domaine borné est remplacé par l’espace tout entier. Plus précisement, nous montrons qu’il existe

Λ>0

tel que cette équation dans

R^N

n’a aucune solution positive pour

λ>Λ

, au moins deux solutions positives pour

λ\in (0,Λ)

, et au moins une solution positive pour

λ\in (−∞,0]∪\{Λ\}

.