bluuebunny/crossref_metadata_2025 huggingface dataset:
A method of maintaining the estimation error at a desired level for acoustic echo canceler systems
Authors: Fujii Kensaku , Ohga Juro
Published: August 2002

The estimation error remaining after the coefficients of an adaptive filter have converged are formulated as a function of the power ratio of the noise to the reference signal and the step gain by the normalized least mean‐square (LMS) algorithm. Usually, when applied to an acoustic echo canceler having large fluctuations in the power ratio, updating the coefficients stops when the power ratio exceeds some specified large value. Naturally, however, this stop operation slows the convergence of the coefficients. In this paper, we propose a method that designs a block implementation of the normalized LMS algorithm and can always update the coefficients by adjusting the block length and the step gain. This control method maintains the estimation error at a specific level by matching the power fluctuations of the reference signal, adjusting the block length, and adjusting the step gain to the noise power fluctuations. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 84(7): 41–52, 2001
Modeling of texture images by use of structuring elements of morphological filters
Authors: Komori Takumi , Taguchi Akira
Published: August 2002

We propose a new model of texture images using morphological filters. This method is based on a linear predictive model [autoregressive (AR) model], which is a representative texture image model. This method embeds the frequency characteristics of the texture image in the AR model. In this paper, we will demonstrate a new model that represents the spatial features of a texture image. Morphological filters can remove the spatial features and are used for pattern spectra. In this paper, we consider embedding the spatial features in the structuring elements of morphological filters and propose an Opening Model (OM) to model the convex up features and a Closing Model (CM) to model the convex down features. We examine the reliability of the proposed model and present improvements to the low‐reliability model. Furthermore, our recognition tests clearly show excellent recognition when OM and CM are used together. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 84(7): 53–62, 2001
An error‐control method for narrow‐band subliminal channels: How to embed more bits in a carrier
Authors: Kobara Kazukuni , Imai Hideki
Published: August 2002

Narrow‐band subliminal channels, discovered by Simmons, yield the possibility of transmitting covert messages by embedding them in cryptographic digital data, such as (EC)DSA signatures. Embedded messages are used for transmitting important information, or are used as watermarks or imprints of the cryptographic digital data. Anyone can use or abuse these channels very easily since cryptographic digital data which are not subliminal‐free are widely used on the Internet. For example, DSA signatures are not subliminal‐free and they are widely used in various applications, such as PGP and SSH2.

A narrow‐band subliminal channel can be considered as a noisy channel when a transmitter generates only a limited number of carriers (a carrier denotes a bunch of data where a covert message is embedded). We propose a way to control the bit‐error property over a narrow‐band subliminal channel, and then evaluate it. In addition, we propose how to reduce the computational cost of generating n carriers as well as a public‐key based narrow‐band subliminal channel. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 84(8): 1–10, 2001
Scalable audio coding based on hierarchical transform coding modules
Authors: Jin Akio , Moriya Takehiro , Iwakami Naoki , Miki Satoshi
Published: August 2002

We propose a method that hierarchically quantizes wideband Modified Discrete Cosine Transform (MDCT) coefficients by developing a module that has a transform coding method primarily for audio as the basic structural unit and freely using this module multiple times at the desired frequencies. The major feature of this method is to implement a simple structure having a high degree of freedom in scalable coding to hierarchically quantize MDCT coefficients over a wide band of frequencies by sharing the proposed module and using it multiple times. This paper presents examples using combinations of the module operating at a sampling frequency of 48 kHz and a bit rate of at least 8 kbit/s. In this example, a bit rate of at least 8 kbit/s and a reconstructed frequency band of at least 4 kHz can be selected as the objective. Subjective evaluation tests are performed to verify the effectiveness of the proposed method. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 84(8): 34–45, 2001
The relationship between the presentation position of a figure and characters on a 3D display and cognitive time
Authors: Shigeta Kazuhiro , Nakayama Minoru , Shimizu Yasutaka
Published: August 2002

When figures and characters are simultaneously presented in a stereoscopically viewed 3D display, we must check the positions of characters in front of or behind the figure for suitable presentation. We have investigated the relationship between the presentation position of a figure and characters, and the cognitive times for the case where characters are inserted into the figure and for the case where the title is attached with the figure. A rectangular parallelepiped was presented by attaching names to the vertices and its response time was measured by confirming the name of the rearmost vertex. It was shown that in 3D presentation of figures, if characters are presented at a depth that is the same as the part corresponding to the characters in the figure, the response time is shortened and cognition is easier than in the presentation of characters on the depth of the display screen. Next, we presented a 3D geometrical shape and title. To decide whether the contents of the two were in good agreement or not, we measured their response times. We also checked the best position of the title on the figure by subjective evaluation experiments. We found that the best position of the title on the figure has good agreement with the mean depth position of the whole figure. If the title is presented at this position, then the response time is shortened and cognition is easier. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 84(12): 10–20, 2001
3D measurement based on intensity‐phase analysis of intensity modulated moiré
Authors: Lu Cunwei , Yamaguchi Akashi , Inokuchi Seiji
Published: August 2002

In the conventional moiré topography, equicontour patterns can be obtained from one image. Since the problem of determination of the number of fringes remains, unique depth distance cannot be measured and hence automatic measurement is difficult. In the present research, the intensity‐modulated projection light and a transmission coefficient‐modulated observation grating are used to generate an intensity‐modulated moiré in which the intensity of the fringes is related to the depth information of a body. Next, by means of an intensity analysis of the moiré pattern, the order of the fringes is determined and the moiré pattern is divided into several depth regions. Finally, in each depth region the phase analysis is carried out to compute the depth value. Based on this research, a simple apparatus is used for resolving the problem described above and automation of moiré three‐dimensional measurement is realized. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 85(1): 71–80, 2002
Torus window in a torus‐doubling generating circuit
Authors: Miyoshi Tetsuya , Nitanai Takashi , Mikami Noriaki , Inaba Naohiko
Published: August 2002

An extremely significant transition phenomenon from a periodic phase to a chaotic phase is known as torus doubling. In this research, we perform computer simulations to study what kind of periodic behavior exists in the chaotic phase transitioned into due to torus doubling in an electrical circuit that generates torus doubling. The result was the generation of an n‐fold torus that is believed to be deeply related to the period of a relatively large window that appears in the chaotic phase in logistic maps such as a 6‐fold, 5‐fold, or 3‐fold torus in the chaotic phase. In this paper, we call the torus generated in the gap of this chaotic phase the torus window. We also analyze a coupled model consisting of a logistic map and a sine‐circle map as the model to explain the mechanism for generating the torus window. We perform computer simulations to show that the 6‐, 5‐, and 3‐fold torus windows are generated in this model. © 2002 Scripta Technica, Electron Comm Jpn Pt 3, 85(5): 56–62, 2002
An error correction approach based on maximum likelihood estimation combined with hidden Markov models
Authors: Yonezaki Tadashi , Yoshida Koji , Yagi Toshio , Shikano Kiyohiro
Published: August 2002

This paper proposes an error‐correction algorithm for channel error using the hidden Markov model (HMM). The proposed method uses two probabilities calculated by the information source model (HMM) and the channel model, under the constraint of the received code sequence, and estimates the transmitted code sequence by maximum likelihood. Consequently, the robustness to error can be improved without adding error‐correcting code by applying the proposed method to the preprocessing of the existing code system. Using the code sequence obtained by quantizing the LSP parameters, the reduction of cepstrum distortion in error correction by the proposed method is examined. It is found that the distortion can be reduced by approximately 39% by the proposed method (16‐state HMM) for a code sequence with 3% random errors. © 2002 Scripta Technica, Electron Comm Jpn Pt 3, 85(5): 63–71, 2002
Radiation characteristics as a function of the gas flow rate emitted from argon torch plasma arc discharge
Authors: Iwao Toru , Miyazaki Hirokazu , Inaba Tsuginori
Published: August 2002

When a reduction of the waste and dissolution of the iron are carried out by means of an arc plasma, the radiant power of the arc should be suppressed. In those cases the radiant power from the plasmas has to be precisely controlled.

Therefore, we tried to measure the radian power from the torch plasma using a power meter. The radiant power was measured to be about 620 to 950 W for an external plasma length of 2 cm at a current of 100 A, with gas flow rates of 4 to 20 l/min (Normal), and increases in proportion to the 0.25 to 0.37 power of the gas flow rate and with the increment of external plasma length and the plasma current.

The total radiant efficiency is 32 to 40% in the condition mentioned above in the sphere model. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 139(3): 1–8, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10006
A genetic algorithm for the optimal sequential partitioning problem
Authors: Araki Hajime , Kaji Taichi , Yamamoto Masahito , Suzuki Keiji , Ohuchi Azuma
Published: August 2002

The optimal sequential problem is defined as the problem of finding the minimum cost partition of the nodes of a directed acyclic graph into subsets of a given size, subject to the constraint that the precedence relationships among the elements are satisfied. A heuristic algorithm based on tabu search has been proposed for this problem [2]. However, there is a tendency for the solutions obtained by tabu search to become trapped in bad local optima in parallel graphs with random edge costs.

In this paper we present a genetic algorithm for the optimal sequential partitioning problem. We develop an effective two‐point partial order crossover satisfying sequential conditions, which preserve better blocks that have a larger sum of edge costs. In this crossover we introduce the roulette selection method to escape local optima. We also assess the effectiveness of the algorithm. The results show that this proposed algorithm outperforms any other algorithm using tabu search in terms of solution quality. © 2001 Scripta Technica, Electr Eng Jpn, 135(4): 43–51, 2001
Optimum design approach for low‐speed, high‐torque permanent magnet motors
Authors: Mizutani Ryoji , Matsui Nobuyuki
Published: August 2002

This paper presents an optimum design approach for low‐speed, high‐torque permanent magnet motors. The approach is divided into two steps: the first consists of the rough estimation of torque by linear analysis, and the second the optimization of the motor configuration by nonlinear FEM analysis. Under restricted dimensional specifications and electrical requirements, a 16‐pole, 18‐coil permanent magnet motor with a rating of 600 Nm and 300 rpm was designed and constructed. © 2001 Scripta Technica, Electr Eng Jpn, 135(4): 52–63, 2001
Optimal operation of power systems constrained by transient stability
Authors: Chen Luonan , Ono Asako , Tada Yasuyuki , Okamoto Hiroshi , Tanabe Ryuya
Published: August 2002

Optimal power flow (OPF) with transient stability constraints is a nonlinear optimization problem in functional space that is not easy to deal with precisely even for small‐scale power systems. Instead of directly tackling this tricky problem, in this paper, OPF with transient stability constraints (OTS) is equivalently converted into an optimization problem in Euclidean space via a constraint transcription, which can be solved by any standard nonlinear programming techniques adopted by OPF. The transformed OTS problem has the same variables as those of OPF in form, and is tractable even for large‐scale power systems with a large number of transient stability constraints. © 2001 Scripta Technica, Electr Eng Jpn, 137(1): 17–27, 2001
Configurations and characteristics of active canceling and compensating circuits for reducing common‐mode voltage generated by voltage‐source PWM inverters
Authors: Ogasawara Satoshi , Zhang Song , Akagi Hirofumi
Published: August 2002

This paper deals with active circuits for cancellation and compensation of common‐mode voltage caused by a PWM inverter. A nonnegligible amount of leakage or ground current flows through stray capacitors between stator windings and the motor frame due to a large step change in the common‐mode voltage at every switching operation of the PWM inverter. First, it is shown experimentally that the active common‐noise canceler (ACC), which has been proposed by the authors, is effective in reducing not only conducted EMI but also motor shaft voltage and bearing current. Next, a new ACC characterized by an isolated power supply is developed to enlarge the applicable voltage range in which it is possible to integrate the ACC with a PWM inverter. Furthermore, the authors propose another type of ACC, the purpose of which is not to achieve complete cancellation but to restrain only a slope in a change of the common‐mode voltage applied to the motor. As a result, the core size of the common‐mode transformer used in the active compensating circuit becomes considerably smaller. Some experimental results show good effects of the proposed active circuits on both ground current and conducted EMI. © 2001 Scripta Technica, Electr Eng Jpn, 137(1): 57–65, 2001
Long‐term conversion efficiency characteristics of thin film solar cells
Authors: Machida Sadayuki , Tani Tatsuo
Published: August 2002

For the optimum design of a photovoltaic power generation system, it is necessary to accurately estimate their annual power output. However, the output of a thin film solar cell (in this paper, layered tandem a‐Si and CdS/CdTe) varies with the spectral distribution of solar radiation as well as with the Staebler–Wronski effect. Changes in the spectral distribution of solar radiation are caused by variations in air mass movement and water vapor content of the atmosphere. The output of thin film solar cells is seriously affected because of their narrow spectral response band. The Staebler–Wronski effect is a phenomenon where the photoconductivity degrades by light irradiation and recovers by heating. Since several factors can affect the output in such a way, it is difficult to accurately estimate the power output of thin film solar cells for an entire year.

In this paper, we will show a method for calculating the power output from the spectral distribution of solar radiation. We will also attempt to clarify the degradation and recovery due to the Staebler–Wronski effect by making a comparison between the conversion efficiency calculated by this method and the conversion efficiency obtained from measured data. The results revealed that the initial degradation of conversion efficiency of layered tandem a‐Si and CdS/CdTe solar cells are 22 and 15% (including the degradation due to dirt 6 to 7%), and the recovery are 5 and 10%. © 2001 Scripta Technica, Electr Eng Jpn, 137(4): 1–9, 2001
Understanding the costs of an environmentally ‘friendly’ common agricultural policy for the European Union11
Authors: Barnes Pamela M. , Barnes Ian G.
Published: August 2002

Part of the bedrock of the European Union's (EU's) Environmental Policy is the principle that those who pollute the environment should pay for the cost of remedying the damage they cause (the polluter pays principle) (Article 174 para. 2 TEC ex Article 130r TEC). In addition environmental objectives must be integrated into all the sectoral policies of the European Union (Article 6 TEC ex Article 3c TEC). The Common Agricultural Policy's (CAP's) role at the centre of the EU's sectoral policies would appear to make it an ideal focus for implementing Article 6 of the Treaty establishing the European Community (TEC). If integration of environmental protection can be achieved in this central area of the EU's activities then a major source of environmental degradation could be overcome. However, if these requirements are applied to European agriculture the sector will face a budgetary and financial crisis of even greater magnitude than at the present time.

Recent reforms of the CAP have been designed with the objective of achieving an agricultural sector that is moving towards sustainability. As this article argues the political, social and economic significance of the agriculture sector is such that national governments of the EU have repeatedly shied away from adopting the measures, which could significantly reduce the pollution from the sector. The proposals for reform made by the Agricultural Commissioner, Franz Fischler, were amended by the meeting of the European Council that took place in Berlin on 24/25 March 1999. These amendments substantially weakened the ambitions of the strategy for development of the EU, the ‘Agenda 2000’ adopted in 1997, for a number of reasons (CEC, 1997). This article examines the reasons for the disappointments with the amended reforms and speculates on the possible future path that may be taken to improve matters. Copyright © 2001 John Wiley & Sons, Ltd and ERP Environment.
When more observations are better than less: a connectionist account of the acquisition of causal strength
Authors: Van Overwalle Frank , Van Rooy Dirk
Published: August 2002

The statistical law of large numbers prescribes that estimates are more reliable and accurate when based on a larger sample of observations. This effect of sample size was investigated on causal attributions. Subjects received fixed levels of consensus and distinctiveness covariation, and attributions were measured after a varying number of trials. Whereas prominent statistical models of causality (e.g. Cheng & Novick, 1990; Försterling, 1992) predict no effect of sample size, adaptive connectionist models (McClelland & Rumelhart, 1988) predict that subjects will incrementally adjust causal ratings in the direction of the true covariation the more observations are made. In three experiments, sample size effects were found consistent with the connectionist prediction. Possible extensions of statistical models were considered and simulated, but none of them accommodated the data as well as connectionist models. Copyright © 2001 John Wiley & Sons, Ltd.
Compensatory biases after ingroup threat: ‘yeah, but we have a good personality’
Authors: Cadinu Maria Rosaria , Cerchioni Marcella
Published: August 2002

It was hypothesized that participants who strongly identify with the ingroup and receive unfavorable feedback about their group in one domain would compensate on alternative dimensions. A group of emergency medical service volunteers received negative, positive or no feedback on their volunteer organization and were asked to rate the ingroup and an outgroup on dimensions alternative to the feedback. As predicted, high identifiers showed an increase in ingroup favoritism after negative feedback (i.e. compensation) and a decrease after positive feedback (i.e. modesty effect). In contrast, low identifiers distanced themselves from the ingroup after negative feedback and accentuated self‐ingroup similarity after positive feedback. Results are discussed in relation to a schema‐maintenance model through compensation (Seta & Seta, 1993) and social identity theory. Copyright © 2001 John Wiley & Sons, Ltd.
Construction of Salmonella typhimurium YG7108 strains, each coexpressing a form of human cytochrome P450 with NADPH–cytochrome P450 reductase
Authors: Fujita Ken‐ichi , Nakayama Kazuo , Yamazaki Yoshiyuki , Tsuruma Kazuhiro , Yamada Masami , Nohmi Takehiko , Kamataki Tetsuya
Published: August 2002

A series of Salmonella typhimurium (S. typhimurium) YG7108 strains, each coexpressing a form of human cytochrome P450 (CYP) (CYP1A1, CYP1A2, CYP1B1, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4, or CYP3A5) together with human NADPH–cytochrome P450 reductase (OR), was established. The parental S. typhimurium YG7108, derived from TA1535, lacks two O6‐methylguanine‐DNA methyltransferase genes, ada and ogt, and is highly sensitive to the mutagenicity of alkylating agents. The expression levels of CYP holo‐protein in the genetically engineered S. typhimurium YG7108 cells, determined by carbon monoxide (CO) difference spectra, ranged from 62 nmol/L culture for CYP2C19 to 169 nmol/L culture for CYP3A4. The expression level of the OR varied, depending on the form of CYP coexpressed, and ranged from 214 to 1029 units/L culture. Each form of CYP expressed in the S. typhimurium YG7108 cells catalyzed the oxidation of a representative substrate at an efficient rate. The rates appeared comparable to the reported activities of CYP expressed in human liver microsomes or CYP in other heterologous systems, indicating that the OR was sufficiently expressed to support the catalytic activity of CYP. These S. typhimurium strains may be useful not only for predicting the metabolic activation of promutagens catalyzed by human CYP but also for identifying the CYP form involved. Environ. Mol. Mutagen. 38:329–338, 2001. © 2001 Wiley‐Liss, Inc.
Pentachlorophenol potentiates benzo[a]pyrene DNA adduct formation in adult but not infant B6C3F1 male mice†
Authors: Bordelon Nancy R. , Donnelly Kirby C. , George S. Elizabeth
Published: August 2002

The objective of this study is to determine whether pentachlorophenol (PCP) alters benzo[a]pyrene (B[a]P)‐induced DNA adduct formation in infant and adult B6C3F1 male mice. Mice were exposed intraperitoneally to 55 μg B[a]P/g body weight (BW) alone and in combination with several doses of PCP in DMSO. The 32P‐postlabeling assay was used to analyze for (±) anti‐7,8‐diol‐9,10‐epoxide‐B[a]P‐N2deoxyguanosine (BPDE‐N2G) adducts formed in liver and lung DNA. Hepatic DNA also was analyzed for 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG) base damage in mice exposed to PCP. 8‐OHdG was not detected at any dose of PCP in infant or adult mice. PCP exhibited an antagonistic effect on BPDE‐N2G accumulation in infant mice exposed to B[a]P in combination with 50 μg PCP/g BW at both 12 and 24 hr. Comparatively, BPDE‐N2G adducts were increased in adult mice exposed to binary mixtures at 24 hr in both hepatic and lung DNA (P < 0.05). Multiple comparison analysis between infant and adult mice revealed that adduct levels in infants exposed to B[a]P alone or in combination with PCP were not different from those observed in adult mice exposed to B[a]P. However, a significant increase in adducts was observed in adult mice exposed to a combination of B[a]P and PCP compared to that in all other treatment groups (P < 0.05). These results suggest that PCP alters the metabolism of B[a]P in both infant and adult mice through different mechanisms, and that infants are not susceptible to the potentiating effects of PCP observed in adult mice. Environ. Mol. Mutagen. 37:164–172, 2001 Published 2001 Wiley‐Liss, Inc.
Comparison of hprt and lacI mutant frequency with DNA adduct formation in N‐hydroxy‐2‐acetylaminofluorene–treated Big Blue® rats†
Authors: Chen Tao , Mittelstaedt Roberta A. , Aidoo Anane , Hamilton L. Patrice , Beland Frederick A. , Casciano Daniel A. , Heflich Robert H.
Published: August 2002

N‐Hydroxy‐2‐acetylaminofluorene (N‐OH‐AAF) is the proximate carcinogenic metabolite of the powerful rat liver carcinogen 2‐acetylaminofluorene. In this study, transgenic Big Blue® rats were used to examine the relationship between in vivo mutagenicity and DNA adduct formation by N‐OH‐AAF in the target liver compared with that in nontarget tissues. Male rats were given one, two, or four doses of 25 mg N‐OH‐AAF/kg body weight by i.p. injection at 4‐day intervals, and groups of treated and control rats were euthanized up to 10 weeks after beginning the dosing. Mutant frequencies were measured in the spleen lymphocyte hprt gene, and lacI mutant frequencies were determined in the liver and spleen lymphocytes. At 6 weeks after beginning the dosing, the hprt mutant frequency in spleen lymphocytes from the four‐dose group was 16.5 × 10−6 compared with 3.2 × 10−6 in control animals. Also at 6 weeks, rats given one, two, or four doses of N‐OH‐AAF had lacI mutant frequencies in the liver of 97.6, 155.6, and 406.8 × 10−6, respectively, compared with a control frequency of 25.7 × 10−6; rats given four doses had lacI mutant frequencies in spleen lymphocytes of 55.8 × 10−6 compared with a control frequency of 20.4 × 10−6. Additional rats were evaluated for DNA adduct formation in the liver, spleen lymphocytes, and bone marrow by 32P‐postlabeling. Adduct analysis was conducted 1 day after one, two, and four treatments with N‐OH‐AAF, 5 days after one treatment, and 9 days after two treatments. N‐(Deoxyguanosin‐8‐yl)‐2‐aminofluorene was the major DNA adduct identified in all the tissues examined. Adduct concentrations increased with total dose to maximum values in samples taken 1 day after two doses, and remained essentially the same after four doses. In samples taken after four doses, adduct levels were 103, 28, and 7 fmol/μg of DNA in liver, spleen lymphocytes, and bone marrow, respectively. The results indicate that the extent of both DNA adduct formation and mutant induction correlates with the organ specificity for N‐OH‐AAF carcinogenesis in the rat. Environ. Mol. Mutagen. 37:195–202, 2001. Published 2001 Wiley‐Liss, Inc.
Spontaneous microdeletions and microinsertions in a transgenic mouse mutation detection system: analysis of age, tissue, and sequence specificity
Authors: Halangoda Asanga , Still Jonathan G. , Hill Kathleen A. , Sommer Steve S.
Published: August 2002

A total of 3497 independent spontaneous mutations were examined using the Big Blue® transgenic mouse mutation detection system. Base substitutions predominate, although 16% of somatic and germline mutations are microdeletions, microinsertions, or deletions combined with insertions. The pattern of microdeletions and microinsertions is similar in both the lacI transgene and the human p53 gene. Single‐base deletions (D1) and insertions (I1) are evenly distributed in the lacI transgene, whereas microdeletions from 2 to 50 bp are clustered at two regions (bp 129–228 and 529–628). The pattern of microdeletions and microinsertions is similar between young (≤3 months) and old (25 months) mice. Brain tissue has a paucity of deletions combined with insertions when compared with that of thymus and nine other tissues (P = 0.01). A 16‐bp deletion at lacI base position 272 is a tissue‐specific hotspot preferentially occurring in brain. Approximately 68 and 93% of D1 and I1, respectively, occur at mononucleotide repeats. The frequencies of D1 and I1 in mononucleotide repeats increase in an exponential manner with the length of the repeat. The lacI transgene shows similarity to the human p53 gene in the pattern of microdeletions and microinsertions and the size distribution of microdeletions. Environ. Mol. Mutagen. 37:311–323, 2001 © 2001 Wiley‐Liss, Inc.
Estimation of rate ratio and relative difference in matched‐pairs under inverse sampling
Authors: Lui Kung‐Jong
Published: August 2002

To increase the efficiency of a study and to eliminate the effects of some nuisance confounders, we may consider employing a matched‐pair design. Under the commonly assumed quadrinomial sampling, in which the total number of matched‐pairs is fixed, we note that the maximum likelihood estimator (MLE) of rate ratio (RR) has an infinitely large bias and no finite variance, and so does the MLE of relative difference (RD). To avoid this theoretical concern, this paper suggests use of an inverse sampling and notes that the MLEs of these parameters, which are actually of the same forms as those under the quadrinomial sampling, are also the uniformly minimum variance estimators (UMVUEs) under the proposed samplings. This paper further derives the exact variances of these MLEs and the corresponding UMVUEs of these variances. Finally, this paper includes a discussion on interval estimation of the RR and RD using these results as well. Copyright © 2001 John Wiley & Sons, Ltd.
Oceanic influence on the precipitation of the south‐east of Venezuela
Authors: Guenni Lelys , Sansó Bruno , Betancourt Lisbeth
Published: August 2002

The Caroní catchment located in the south‐east of Venezuela accounts for 70 per cent of the total hydropower energy of the country. On a year to year basis, it has been shown that low frequency large scale ocean‐atmosphere phenomena are highly coupled to the hydroclimatology of the region, El Niño‐Southern Oscillation (ENSO) being a major forcing mechanism of climatic and hydrological anomalies. Regional differences in amplitude and timing are due to complex orographic interactions, land surface‐atmosphere feedback mechanisms and the evolution of dominant synoptic meteorological conditions. A detailed analysis of the relationship between rainfall and several large scale ocean‐atmospheric variables was carried out to determine the potential use of large scale climatic information as predictors of the rainfall anomalies over the region. The problem was tackled in two ways: (a) first a seasonal dynamic rainfall model was fitted to monthly rainfall for different locations. In this case rainfall is assumed as a normal variate w which has been transformed to account for its departure from normality and truncated to account for the positive probability mass of zero values, which corresponds to negative values of the normal variable. The time series of the model parameters and the macroclimatic variables are inspected for their potential relationship with local rainfall via the stochastic model. (b) Second, dynamic linear regression models between the macroclimatic variables as predictors and the rainfall anomalies as predictant were fitted to evaluate and quantify the significance of these dependencies. Consistent patterns are observed with the Tropical Atlantic and Pacific ocean temperature anomalies, in which a significant negative relationship has been present since 1976, indicating an overall decrease (increase) in rainfall when the Pacific and the Tropical Atlantic are warmer (colder) than normal. In all cases the results suggest that the relationships between rainfall anomalies and the macroclimatic variables are not constant with time. Copyright © 2002 John Wiley & Sons, Ltd.
Numerical study of Ashiyahama residential building damage in the Kobe Earthquake
Authors: Takabatake Hideo , Nonaka Taijiro
Published: August 2002

Studies are made on the structural damage at the Ashiyahama residential high‐rise steel building complex due to the Hyogo‐ken Nanbu Earthquake (Kobe Earthquake), which occurred on 17 January 1995. The axial breakage of very thick‐plated steel columns of the mega‐structure is unprecedented and has been attracting the special attention of structural engineers. The cause of the damage is first investigated from numerical computation with recourse to an explicit method of dynamic analysis based on a continuous medium. The numerical result is compared with that obtained from a conventional multi‐mass lumped stiffness model combined with an equivalent lateral‐force procedure. By comparing both the numerical results, the latter conventional method is shown to be inadequate for achieving earthquake‐resistant capability. The destructive power of the ground motion is found to have exceeded the horizontal earthquake‐resistant capacity that is prescribed in the structural design criteria. Great axial stresses are produced in columns by combined action of bending moment and axial force due to overturning moment. The fracture of heavy steel columns is caused from only the horizontal component of seismic ground motion. Actual locations of significant damage are closely related to the occurrence of plastic hinges in the analysis. It is emphasized as a warning to avoid yielding concentration in particular storeys. Lastly, recommendations to enhance earthquake‐resistant design are proposed from a practical point of view. Copyright © 2001 John Wiley & Sons, Ltd.
Non‐stationary seismic response of tanks with soil interaction by wavelets
Authors: Chatterjee Pranesh , Basu Biswajit
Published: August 2002

A wavelet‐based random vibration theory has been developed for the non‐stationary seismic response of liquid storage tanks including soil interaction. The ground motion process has been characterized via estimates of statistical functionals of wavelet coefficients obtained from a single time history of ground accelerations. The tank–liquid–soil system has been modelled as a two‐degree‐of‐freedom (2‐DOF) system. The wavelet domain equations have been formulated and the wavelet coefficients of the required response state are obtained by solving two linear simultaneous algebraic equations. The explicit expression for the instantaneous power spectral density function (PSDF) in terms of the functionals of the input wavelet coefficients has been obtained. The moments of this PSDF are used to estimate the expected pseudo‐spectral acceleration (PSA) response of the tank. Parametric variations are carried out to study the effects of tank height, foundation natural frequency, shear wave velocity of soil and ratio of the mass of tank (including liquid) to the mass of foundation on the PSA responses of tanks. Copyright © 2001 John Wiley & Sons, Ltd.
Initiation of a multiple peat slide on Cuilcagh Mountain, Northern Ireland
Authors: Dykes A. P. , Kirk K. J.
Published: August 2002

In October 1998 a multiple peat slide occurred on the northern slopes of Cuilcagh Mountain, Co. Fermanagh, in response to a high‐magnitude rainfall event. Few peat slides have been recorded in Ireland, and a detailed field survey and investigation of the failure was undertaken within four weeks of the event. The morphological evidence indicated a distinct sequence of events which appeared to begin with the failure of a small segment of slope above a degraded transverse drainage ditch which was cut less than ten years previously. This segment of slope was no more than 42 m wide and 25 m long, with 0·7 m of peat overlying up to 0·5 m of a pale coloured clay, the latter containing small pipes and resting on the surface of a darker coloured loamy material. The failure surface was located at or near the base of the pale clay layer. Finite element software was used to model hydrological conditions within the upper segment of slope and to calculate factors of safety for different slope configurations including the presence or absence of a drain or a subsurface pipe. Using the peak shear strength of the pale clay, as determined in the laboratory, both the drain and subsurface pipes were required to obtain a factor of safety of 1·0 or less. Allowing for the uncertainties associated with the hydrological modelling of the pipes, it is suggested that the cutting of the drain and the hydrological impacts of its subsequent degradation are ultimately responsible for the failure. Copyright © 2001 John Wiley & Sons, Ltd.
Modelling the response of sprinklers in compartment fires
Authors: Gupta A. K.
Published: August 2002

Alpert's expressions are used extensively to calculate the maximum temperature and velocity in the ceiling‐jet at any distance, r, from the fire axis. These expressions are valid for unconfined ceilings insofar as the environment outside the ceiling‐jet is uniform in temperature and is atmospheric ambient. In compartments the outward flow of hot gases is checked by the presence of bounding walls and so a layer of hot gases is formed in the upper portion of the compartment. The environment outside the ceiling‐jet is no longer ambient atmospheric. Expressions due to Alpert becomes unsuitable, unless the effects of the accumulated hot layer are included in these expressions.

The effect of the upper layer temperature has been taken by assuming that since the ceiling‐jet is completely submerged in the upper hot gas layer, the entrained gases are drawn from this layer only instead of the ambient atmospheric air at T∞. Thus T∞ has been replaced by TL in the Alpert's empirical expression for ceiling‐jet temperatures. The proposed equation is then used to calculate the response time of sprinklers fitted in compartments of varying sizes. Calculations have been done for identical conditions to those employed by Evans and compared. Comparison has also been made with Cooper's LAVENT model predictions. The study shows that the present model is capable of predicting the maximum, as well as average, temperatures in the ceiling‐jets submerged in the hot gas layer. Copyright © 2001 John Wiley & Sons, Ltd.
Composition of a new essential oil type of Lippia alba (Mill.) N.E. Brown from Uruguay
Authors: Lorenzo Daniel , Paz Daniel , Davies Philip , Vila Roser , Cañigueral Salvador , Dellacassa Eduardo
Published: August 2002

The essential oil of aerial parts of Lippia alba (Mill.) N. E. Brown cultivated in a small‐scale experimental area was analysed by GC and GC–MS (quadrupole). Twenty‐seven components were identified, corresponding to 93% of the total oil. The enantiomeric distribution of α‐pinene, sabinene, limonene and linalool was studied by multidimensional GC–GC. The major component was linalool (55%) with an enantiomeric purity of 99% for (+)‐linalool. Comparison with previous results suggested the presence of a new linalool‐rich chemotype for L. alba. Copyright © 2001 John Wiley & Sons, Ltd.
Volatile constituents from the leaves of four Libanothamus species from the Venezuelan Andes
Authors: Usubillaga A. , Aparicio R. , Romero M. , Rojas L. B. , Khouri N.
Published: August 2002

The essential oil from the leaves of Libanothamus humbertii Cuatr., Libanothamus lucidus (Aristeg) Cuatr., Libanothamus nerifolia (B. ex H) Ernst, and Libanothamus occultus (Blake) Cuatr, collected in the Andes near Merida, were obtained by hydrodistillation. The oil yield varied between 0.05% and 0.13% and monoterpene hydrocarbons constituted 83.6–90% of the oils. Limonene (19.4%) is the most abundant component in L. humbertii, α‐thujene (30.2%) in L. lucidus, sabinene (25.6%) in L. nerifolia and α‐pinene (31.3%) in L. occultus. Copyright © 2001 John Wiley & Sons, Ltd.
A Lagrangian boundary element approach to transient three‐dimensional free surface flow in thin cavities
Authors: Zhang Jie , Khayat Roger E.
Published: August 2002

The lubrication theory is extended for transient free‐surface flow of a viscous fluid inside a three‐dimensional thin cavity. The problem is closely related to the filling stage during the injection molding process. The pressure, which in this case is governed by the Laplace's equation, is determined using the boundary element method. A fully Lagrangian approach is implemented for the tracking of the evolving free surface. The domain of computation is the projection of the physical domain onto the (x, y) plane. This approach is valid for simple and complex cavities as illustrated for the cases of a flat plate and a curved plate. It is found that the flow behavior is strongly influenced by the shape of the initial fluid domain, the shape of the cavity, and inlet flow pressure. Copyright © 2001 John Wiley & Sons, Ltd.
Numerical simulation of high‐Reynolds number flow around circular cylinders by a three‐step FEM–BEM model
Authors: Young D. L. , Huang J. L. , Eldho T. I.
Published: August 2002

An innovative computational model, developed to simulate high‐Reynolds number flow past circular cylinders in two‐dimensional incompressible viscous flows in external flow fields is described in this paper. The model, based on transient Navier–Stokes equations, can solve the infinite boundary value problems by extracting the boundary effects on a specified finite computational domain, using the projection method. The pressure is assumed to be zero at infinite boundary and the external flow field is simulated using a direct boundary element method (BEM) by solving a pressure Poisson equation. A three‐step finite element method (FEM) is used to solve the momentum equations of the flow. The present model is applied to simulate high‐Reynolds number flow past a single circular cylinder and flow past two cylinders in which one acts as a control cylinder. The simulation results are compared with experimental data and other numerical models and are found to be feasible and satisfactory. Copyright © 2001 John Wiley & Sons, Ltd.
Numerical simulation of flow in a circular duct fitted with air‐jet vortex generators
Authors: Küpper Christoph , Henry Frank S.
Published: August 2002

Most of the fundamental studies of the use of air‐jet vortex generators (AJVGs) have concentrated on their potential ability to inhibit boundary layer separation on aerofoils. However, AJVGs may be of use in controlling or enhancing certain features of internal duct flows. For example, they may be of use in controlling the boundary layer at the entrance to engine air intakes, or as a means of increasing mixing and heat transfer. The objective of this paper is to analyse the flow field in the proximity of an air‐jet vortex generator array in a duct by using two local numerical models, i.e. a simple flat plate model and a more geometrically faithful sector model. The sector model mirrors the circular nature of the duct's cross‐section and the centre line conditions on the upper boundary. The flow was assumed fully turbulent and was solved using the finite volume, Navier–Stokes Code CFX 4 (CFDS, AEA Technology, Harwell) on a non‐orthogonal, body‐fitted, grid using the k–ε turbulence model and standard wall functions. Streamwise, vertical and cross‐stream velocity profiles, circulation and peak vorticity decay, peak vorticity paths in cross‐stream and streamwise direction, cross‐stream vorticity profiles and cross‐stream wall shear stress distributions were predicted. Negligible difference in results was observed between the flat plate and the sector model, since the produced vortices were small relative to the duct diameter and close to the surface. The flow field was most enhanced, i.e. maximum thinning of the boundary layer, with a configuration of 30° pitch and 75° skew angle. No significant difference in results could be observed between co‐ and counter‐rotating vortex arrays. Copyright © 2002 John Wiley & Sons, Ltd.
A finite volume–multigrid method for flow simulation on stratified porous media on curvilinear co‐ordinate systems
Authors: Calvo Pablo , Lisbona Francisco
Published: August 2002

This paper presents a numerical study of infiltration processes on stratified porous media. The study is carried out to examine the performance of a finite volume method on problems with discontinuous solutions due to the transmission conditions in the interfaces. To discretize the problem, a curvilinear co‐ordinate system is used. This permits matching the interface with the boundary of the control volumes that interchange fluxes between layers. The use of the multigrid algorithm for the resulting systems of equations allows problems involving a large number of nodes with low computational cost to be solved. Finally, some numerical experiments, which show the capillary barrier behaviour depending on the material used for the different layers and the geometric design of the interface, are presented. Copyright © 2001 John Wiley & Sons, Ltd.
Substitution between revenue futures and price futures contracts: A note
Authors: Hennessy David A.
Published: August 2002

In recent years, commercial interest has been expressed in agricultural revenue insurance instruments.
Participating parties may look to futures markets to offset assumed positions. In this note, conditions are
identified such that revenue futures contracts are perfect substitutes for price futures contracts. If these
conditions approximate reality, then it would seem questionable whether sufficient interest would exist to
sustain markets in both futures contracts. © 2002 Wiley Periodicals, Inc. Jrl Fut Mark 22:387–391,
2002
Mean Reversion and Basis Dynamics
Authors: Theobald Michael , Yallup Peter
Published: August 2002

An analytical relationship between basis change autocorrelations and thin trading effects together with
partial adjustment factors is developed. Less than full price adjustments are demonstrated to lead to negative
autocorrelations in basis innovation series in addition to those induced by thin trading effects. Numerical and
empirical analyses explore the interrelationships between these effects and provide evidence for the presence of
both effects in intradaily cash and futures data. © 2001 John Wiley & Sons, Inc. Jrl Fut Mark 21:
797–818, 2001
Hedging in Futures and Options Markets with Basis Risk
Authors: Mahul Olivier
Published: August 2002

This paper analyzes the hedging decisions for firms facing price and basis risk. Two conditions assumed in
most models on optimal hedging are relaxed. Hence, (i) the spot price is not necessarily linear in
both the settlement price and the basis risk and (ii) futures contracts and options on futures at
different strike prices are available. The design of the first‐best hedging instrument is first derived
and then it is used to examine the optimal hedging strategy in futures and options markets. The role of options
as useful hedging tools is highlighted from the shape of the first‐best solution. © 2002 John Wiley
& Sons, Inc. Jrl Fut Mark 22:59–72, 2002
Genome‐wide search for loss of heterozygosity in Burkitt lymphoma cell lines
Authors: Sobol Hagay , Benziane Athmane , Kerangueven Fabienne , Yin Luo , Noguchi Tetsuro , Pauly Suzanne , Eisinger François , Longy Michel , Romeo Giovanni , Lenoir Gilbert , Birnbaum Daniel
Published: August 2002

The molecular biological characteristics of Burkitt lymphoma (BL), in addition to the presence of the Epstein‐Barr virus (EBV) in some forms, relies on well‐characterized alterations, such as MYC translocations and TP53 inactivations. To ascertain the number and location of other genome alterations, we used 191 polymorphic markers in a genome‐wide search for loss of heterozygosity (LOH) in 31 Burkitt lymphoma cell lines and their normal counterparts. We were able to distinguish two types of altered allelic patterns: a bona fide LOH profile, indicative of deletion (LOH), and a profile indicative of increased dosage (ID). The former type was most frequent at chromosome arm 17p, most likely indicating TP53 gene inactivation. Increased dosage at 1q was found almost exclusively in non‐EBV cell lines (P < 0.00004) and correlated well with karyotypic abnormalities affecting region 1q21‐25. Our results suggest that a gene important for BL pathogenesis is located in region 1q21‐25 and that the activation of this gene mimics the effects of EBV. © 2002 Wiley‐Liss, Inc.