bluuebunny/crossref_metadata_2025 huggingface dataset:
A digital secure image communication scheme based on the chaotic Chebyshev map
Authors: Liao Xiaofeng , Li Xueming , Pen Jun , Chen Guanrong
Published: June 2004

In this paper, a simple image secure communication scheme based on the chaotic Chebyshev map and chaos synchronization is proposed. The scheme relies on the excellent correlation property of chaotic sequences, which is very desirable for secure image communication. The results obtained by computer simulation indicate that the transmitted source image can be correctly and reliably recovered using the proposed scheme, even through a noisy channel. Notably, the scheme possesses relatively high security and can be easily implemented. Moreover, the quality of the recovered image is satisfactory, quantified by such common criteria as the bit‐error rate performance. Copyright © 2004 John Wiley & Sons, Ltd.
An active scheduling paradigm for open adaptive network environments
Authors: Hussain S.A.
Published: June 2004

Active and programmable networks change the functionality of routers and switches by using agents and active packets. This paper presents a new packet scheduling scheme calledActive Schedulingto control and maintain QoS parameters in virtual private networks (VPNs) within the confines of adaptive and programmable networks. InActive Schedulingan agent on the router monitors the accumulated queuing delay for each service. In order to control and to keep the end‐to‐end delay within the bounds, the weights for services are adjusted dynamically by agents on the routers spanning the VPN. If there is an increase or decrease in queuing delay of a service, an agent on a downstream router informs the upstream routers to adjust the weights of their queues. This keeps the end‐to‐end delay of services within the specified bounds and offers better QoS compared to VPNs using static WFQ. The paper describes the algorithm for Active Scheduling, and presents simulation results and these are compared with WFQ. Copyright © 2004 John Wiley & Sons, Ltd.
Presenilin 1 is essential for cardiac morphogenesis
Authors: Nakajima Mitsunari , Moriizumi Eiko , Koseki Haruhiko , Shirasawa Takuji
Published: June 2004

Presenilin 1 (PS1) is the gene responsible for the development of early‐onset familial Alzheimer's disease. PS1‐deficient mice have been reported to show defects in neurogenesis, somitogenesis and angiogenesis. Here, we report cardiac anomaly in PS1‐deficient mice: the mutant hearts exhibited ventricular septal defect, double outlet right ventricle, and stenosis in the pulmonary artery. Immunohistochemistry using anti‐PS1 antibody revealed the prominent expression of PS1 in mesenchymal cells at the septal area of the wild‐type heart. These results suggest that PS1 may play an essential role in heart development. Developmental Dynamics 230:795–799, 2004. © 2004 Wiley‐Liss, Inc.
Critical role for retinol in the generation/differentiation of angioblasts required for embryonic blood vessel formation
Authors: LaRue Amanda C. , Argraves W. Scott , Zile Maija H. , Drake Christopher J.
Published: June 2004

Numerous studies demonstrate that vitamin A (retinol) deficiency causes abnormal cardiovascular morphogenesis. We evaluated the impact of retinol deficiency on the regulation of the numbers of endothelial cells and angioblasts (endothelial progenitors) produced during embryonic quail development. At the one‐somite stage, there were no discernible differences in the mean number of endothelial cells or angioblasts in normal and retinol‐deficient embryos. However, retinol‐deficient embryos at the three‐somite stage had an increase in the mean number of endothelial cells but no difference in the mean number of angioblasts. By contrast, retinol‐deficient embryos at the five‐somite stage have 61% of the normal number of endothelial cells and 12% of the normal number of angioblasts. Similarly, retinol‐deficient embryos at the 10‐somite stage had 71% and 60% of normal numbers of endothelial cells in capillary‐like networks and the sinuses venosus, respectively. Furthermore, we show that retinol deficiency did not elicit a global reduction in mesodermal cell numbers but was specific to cells of the endothelial lineage. Taken together, our findings suggest that vascular abnormalities observed under conditions of retinol deficiency are due to reduction in the number of angioblasts and consequently an insufficiency in the number of endothelial cells required to build complex vascular networks. Developmental Dynamics 230:666–674, 2004. © 2004 Wiley‐Liss, Inc.
Performance improvement of PRML system using AR channel model in perpendicular magnetic recording
Authors: Okamoto Yoshihiro , Masunari Noriyuki , Yamamoto Hirofumi , Osawa Hisashi , Saito Hidetoshi , Muraoka Hiroaki , Nakamura Yoshihisa
Published: June 2004

We studied an improvement in the error rate performance of the PRML system in perpendicular magnetic recording. We improved the decoder performance by adopting an AR channel model in the estimation calculation of the input sequence in Viterbi decoding. We determined the required signal‐to‐noise ratio at the readout point and the line recording density needed to achieve a bit error rate of 10−4 from computer simulations and recording and playback tests using a spinstand, and compared them to a conventional PRML system. The results clearly showed improved performance in the PRML system by using a Viterbi decoder employing the AR channel model. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(7): 18–27, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10170
Acoustic models of the elderly for large‐vocabulary continuous speech recognition
Authors: Baba Akira , Yoshizawa Shinichi , Yamada Miichi , Lee Akinobu , Shikano Kiyohiro
Published: June 2004

Widespread use of large‐vocabulary continuous speech recognition systems has recently occurred, encouraging the application of speech recognition techniques to various problems. One of the factors that adversely affect the performance of speech recognition systems is a mismatch between the acoustic properties of the speech of the system user and the acoustic model. The speech of young or middle‐aged adults is generally used in constructing the acoustic model. Thus, a mismatch occurs between the model and the acoustic properties of the speech of the elderly, which may degrade the recognition rate. In this study, a large‐scale elderly speech database (200 sentences ×301 subjects) is used to train the acoustic model, and the resulting elderly acoustic model is evaluated by using a large‐vocabulary continuous speech recognition system. In the experiments, the word recognition rate was improved by 3 to 5% compared to the recognition results of an acoustic model trained by young or middle‐aged adult speech, namely, by the JNAS speech database (150 sentences ×260 subjects, average 28.6 years). It is also verified experimentally that the recognition rate is further improved in speaker adaptation to elderly speech by making use of an acoustic model trained by elderly speech. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(7): 49–57, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20101
TelMeA: Effects of avatar‐like agents on asynchronous community systems and implementation in a web‐based system
Authors: Takahashi Toru , Takeda Hideaki
Published: June 2004

The effects of using an animation agent (avatar‐like agent) as an interface of an asynchronous community system, TelMeA, a system with such an agent implemented by the authors, and the results of test‐running this system are discussed in this paper. Psychological test results show that the agent not only has the effect of speaking simply for a speaker, but also differentiating between multiple speakers. Thus, use of this agent allows easy understanding of the state of human relations etc. within a community from conversation content and an increased awareness of the conversation context. In addition, the agent can represent nonlanguage expressions such as expressions, gestures, approaching, finger pointing, and the like by movements on a screen or animation. TelMeA is a system supporting asynchronous conversations by multiple persons through exchanges of scripts describing multimodal behavior of the above‐mentioned expressions via agents displayed on a web page. It was found from the results of test‐running TelMeA for 9 days that 17% of nonlanguage expressions were observed in total utterances and that the functioning of TelMeA was evaluated highly by its users. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(7): 58–69, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20102
Calculation of the correlation coefficient in the DCT domain
Authors: Inazumi Yasuhiro , Warashina Takuji , Yoshida Toshiyuki
Published: June 2004

A method is studied for deriving the coefficient of correlation ρ between pixels from the DCT coefficient. The simplest way is to derive the pixel values by applying the fast inverse DCT to the DCT coefficients of interest and then to calculate ρ according to the definition in the image domain. When only the value of ρ is needed, the decoding operation by application of the inverse DCT is redundant. In this paper, a method of direct calculation of ρ in the DCT domain is proposed. First, the definition of ρ in the image domain is expressed in terms of the DCT coefficients. By using the orthogonality of DCT, the total amount of calculation is reduced so that ρ can be calculated with only 50% as much calculation as in the case with the fast inverse DCT. Next, for data such as picture images with high correlation, the energy of the DCT coefficients is concentrated in the lower frequencies. This property is used in reducing the amount of calculation to about 30% by neglecting the DCT coefficients at higher frequencies. The proposed method is applied to a number of picture images to verify its validity. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(12): 49–59, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10153
Accuracy of relative distance measurement with ultra wideband system
Authors: Shimizu Yuichiro , Sanada Yukitoshi
Published: June 2004

Due to recent research and relaxed regulations, ultra wideband (UWB) wireless systems have come into practical use. UWB uses a wide bandwidth of several gigahertz and ultra‐short period pulses. Therefore, the position resolution is superior. If pulse locking exists between the transmitter and the receiver, the pulse locking point is shifted if the distance between the transmitter and the received is varied. This shift is corrected by DLL. By measuring this correction, relative position detection is possible. This paper studies the characteristics obtained when using a delay‐lock loop (DLL) for pulse locking, which is important for relative position detection. In particular, it focuses on an environment in which local timing jitter exists. The template waveform on the receiving side and the existence or nonexistence of the loop filter and data modulation are also studied in order to improve the characteristics of the entire system. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(12): 26–36, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ ecjc.20075
Impact of successive interference canceler on the performance of ubiquitous antenna‐based SDMA system
Authors: Okamura Shutai , Okada Minoru , Tsukamoto Katsutoshi , Komaki Shozo , Yamamoto Heiichi
Published: June 2004

In this paper, in order to improve the packet error rate of a ubiquitous antenna‐based SDMA (Space Division Multiple Access) system, the application of a successive interference canceler (SIC) is proposed. In a ubiquitous antenna‐based SDMA system, radio base stations (RBS) distributed throughout the service area are connected by radio‐on‐fiber links to the central control station (CCS). By performing all signal processing functions such as wireless modulation and demodulation at the CCS, simultaneous reception of several signals transmitted in the same frequency range is made possible and hence the frequency utilization efficiency can be enhanced. When an SIC is applied to the ubiquitous antenna system, the magnitude relationship of the power received by the user is different for each RBS as the RBSs are distributed at several locations. Hence, strength comparison of the received power is not easy. In the SIC proposed in this paper, the SINR (Signal to Interference plus Noise Ratio) after MMSE is estimated, and then the interference is eliminated according to size. A computer simulation is performed assuming a QPSK‐OFDM (Quadrature Phase Shift Keyed–Orthogonal Frequency Division Multiplex) signal with a coding rate of 1/2 in accordance with the IEEE 802.11a specification. It is made clear that by the use of the proposed scheme the required transmitted power satisfying the requirement of an average BER of 10−4can be reduced by about 7.2 dB, and that with a packet transmission success rate of 0.9 it can be reduced by 8 dB. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(12): 10–25, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20076
Low‐powered and accelerative synchronization in the coupled system of nonlinear hardware oscillators
Authors: Maeda Yoshinobu , Sakaguchi Shinya , Makino Hideo , Doi Shinji
Published: June 2004

In a diffusively coupled system using a mathematical model of heart muscle, an acceleration phenomenon has been reported in which the oscillation period after coupling becomes smaller than the intrinsic period prior to coupling. In the present research, an acceleration phenomenon is observed in a coupled system of an electronic circuit model. Also, by using an electronic circuit simulator, the conditions causing acceleration in a coupled system are studied. The power consumption of a coupled system is numerically derived. It is found that the power consumption can decrease when the acceleration phenomenon takes place. Heart muscle cells not only accelerate the oscillation (or increase the number of oscillations) by mutual coupling but also reduce the power (or energy) consumption at the same time. It is suggested that efficient information transmission may be carried out with less energy overall. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(12): 1–9, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20081
Development of instruction tracer for performance evaluation
Authors: Morimoto Hiroyuki , Komiyama Syoichiro , Mouri Koichi , Yoshizawa Yasufumi
Published: June 2004

Applications such as network server programs and distributed multimedia applications, in which system calls and input/output processing are frequently used, are highly dependent on the operating system. In evaluating the performance of such applications, the execution data for the application and the operating system must be acquired consistently. Conventionally, the performance of a program has mostly been examined through the occurrences of particular events, by means of the performance monitoring function provided by the CPU. The most frequent is the measurement of time based on the cumulative number of clocks in the CPU. In the present computer environment, these values vary depending on the measurement timing. In addition, in these methods, the information concerning the time of occurrence is not preserved when multiple events occur, and there is no means of analyzing the dependency among the events. It is thus difficult for the user to locate the reason for the variation of the value. In order to solve these problems, this paper considers memory access as the measure for performance evaluation. The “SURU” kernel level instruction tracer, the set of “SURU tools” that analyze the output data from TSURU, and the “SURU library” used to construct TSURU tools, are proposed. TSURU can acquire dynamic information such as the execution instruction sequence, the refer address, and the interrupt. Using the TSURU tools to analyze the data acquired by TSURU, the operation of the program under consideration can be traced, and the execution time and the page fault generation rate can be determined. Based on this result, the factors responsible for performance degradation can be analyzed, and the performance improvement obtainable by solving the problem can be estimated. With the TSURU library, the user can easily construct TSURU tools. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(12): 73–83, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20131
Human motion tracking using nonsynchronous multiple observations
Authors: Mori Hiroki , Utsumi Akira , Ohya Jun , Yachida Masahiko , Nakatsu Ryohei
Published: June 2004

This paper proposes a method of tracking a human object by using nonsynchronous multiple‐viewpoint images. The proposed method tracks human forms efficiently by using a Kalman filter to integrate observed information which is obtained nonsynchronously from multiple viewpoints. The experimental system is composed of multiple observation nodes, which operate nonsynchronously to process the multiviewpoint images, a tracking node, which tracks the human figure, and the discovering node, which finds the human figure. The image features are matched to the tracking model in the observation node based on the prediction of the observed value which is sent from the tracking node. The image features matched to the model are sent to the tracking node, and the tracking model is updated. The image features which are not matched are sent to the discovering node to find a new human figure. With the proposed approach, it is possible to construct a large‐scale tracking system while reducing the deterioration of processing efficiency and the redundancy among observations that occur in synchronous systems. The effectiveness of the proposed method is demonstrated by an experiment using real images. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(12): 84–93, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20132
Distinct expression patterns of polycomb oncoproteins and their binding partners during the germinal center reaction
Authors: van Galen Joost C. , Dukers Danny F. , Giroth Cindy , Sewalt Richard G. A. B. , Otte Arie P. , Meijer Chris J. L. M. , Raaphorst Frank M.
Published: June 2004

Polycomb group (PcG) genes encode two chromatin‐binding protein complexes, the PRC1 and the PRC2 PcG complexes, which are essential for the maintenance of cell identity and play a role in oncogenesis. PcG complexes were recently identified as novel regulators of hematopoiesis, and appear to be expressed in a non‐overlapping pattern in resting and mature follicular B cells. Using highly specific antisera in combination with immunohistochemistry and triple immunofluorescence, we investigated the expression pattern of nine human PcG genes in germinal center (GC) B cells and highly purified germinal center B cell subpopulations. PcG proteins were detected in characteristic binding patterns that were not necessarily related to mutually exclusive expression of the two PcG complexes. We conclude that the two PcG complexes are expressed throughout GC development, and that the fine composition of each complex is determined by the differentiation status of the cell. In addition, a subset of dividing cells with a centrocyte CD marker profile was identified that co‐expresses core components of the PRC1 and PRC2 complex. We propose that these cells reflect a transitional stage between resting and dividing follicular B lymphocytes, and that they possibly represent the healthy precursors of nodal large B cell lymphomas.
Mini‐review: The role of peptidoglycan recognition in innate immunity
Authors: Girardin Stephen E. , Philpott Dana J.
Published: June 2004

The importance of peptidoglycan detection in the host innate immune response has long been underestimated. However, the recent identification of proteins involved in the sensing of peptidoglycan in both mammals and Drosophila has revealed that the detection of this microbial motif is key to the defense response. In Drosophila, the peptidoglycan‐recognition proteins (PGRP) are the initial sensors of infecting bacteria that then trigger a cascade ultimately leading to the expression of antimicrobial peptides. In mammals, PGRP also exist and although they bind peptidoglycan, the role of these proteins in innate immune responses remains to be clearly defined. In contrast, the Nod proteins (Nod1 and Nod2), which are also involved in peptidoglycan sensing, appear to play a key role in innate immunity against bacteria by triggering host defense responses through the activation of the transcription factor, NF‐κB. Interstingly, mutations in Nod2 are related to increased susceptibility to Crohn's disease, thereby implicating defective bacterial sensing in the development at this chronic disease. In this review, we will focus on the recent findings concerning mammalian and Drosophila proteins involved in peptidoglycan recognition and the putative role of these proteins in the innate immune defense response.

See an article in this issue http://dx.doi.org/10.1002/eji.200425229
NOD2 mediates anti‐inflammatory signals induced by TLR2 ligands: implications for Crohn's disease
Authors: Netea Mihai G. , Kullberg Bart Jan , de Jong Dirk J. , Franke Barbara , Sprong Tom , Naber Ton H. J. , Drenth Joost P.H. , Van der Meer Jos W.M.
Published: June 2004

Mutations of the NOD2 gene have been associated with an increased susceptibility to Crohn's disease, but the pathogenetic mechanisms mediated by NOD2 remain elusive. In the present study, we demonstrate that the 3020insC frameshift‐mutation in the NOD2 gene associated with Crohn's disease results in defective release of IL‐10 from blood mononuclear cells after stimulation with the Toll‐like receptor (TLR)2 ligands, peptidoglycan and Pam3Cys‐KKKK, but not with bacterial LPS, a TLR4 ligand. The potential pathophysiological significance of this finding in patients with Crohn's disease and who are homozygous for this NOD2 mutation was substantiated by the finding of decreased anti‐inflammatory cytokine release when cells from these patients were stimulated with different species of Bacteroides, an enteric microorganism implicated in the pathogenesis of Crohn's disease. In conclusion, defective NOD2 function results in a pro‐inflammatory cytokine bias after stimulation of mononuclear cells with TLR2 stimuli, and this could contribute to the overwhelming inflammation seen in Crohn's disease.

See Mini‐review in this issue http://dx.doi.org/10.1002/eji.200425095
Formation of the complex linear dunes in the central Taklimakan Sand Sea, China
Authors: Wang Xunming , Dong Zhibao , Zhang Jiawu , Qu Jianjun
Published: June 2004

The formation of the complex linear dunes in the central Taklimakan Sand Sea is discussed based on analyses of wind regimes, sand grain size distributions on the topography of the dunes, and a combination of geomorphic and geophysical investigations into the morphology of the dunes. Complex linear dune formation is shown to have ﬁve stages. Analysis clearly shows that under the control of wind regime, sand supply and other factors, the simple linear dunes move sideways while they evolve. This is the main cause for the formation of complex linear dunes in the central Taklimakan Sand Sea. We have not collected enough evidence to show whether the complexity of the complex linear dunes is left over from previous wind regimes or whether the previous wind regimes had different dominant wind directions compared to those of modern winds. The evolutionary processes of complex linear dunes in the region partly support the theory of ‘barchan evolution’ but do not support the ‘roll‐vortex’ and ‘bimodal wind regime’ hypotheses. After the complex linear dunes were developed, the local wind regime and the other controls such as sand supply suggest it is possible for them to maintain their linear shape. The evolutionary process discussed is limited to the region indicated in this paper, and may not be applicable to the whole Taklimakan Sand Sea. There are different evolutionary processes in different duneﬁelds because of variations in the factors that control complex linear dune formation. Copyright © 2004 John Wiley & Sons, Ltd.
Origin of honeycombs and related weathering forms in Oligocene Macigno Sandstone, Tuscan coast near Livorno, Italy
Authors: McBride Earle F. , Picard M. Dane
Published: June 2004

Two types of cavernous‐weathering features are exposed in the Oligocene Macigno Sandstone along 5 km of the Tuscan coast south of Livorno, Italy. Honeycomb cells (type 1 features) are typical closely spaced, more or less circular pits of centimetre scale that have been eroded 2 to 6 cm below the general surface of bedding planes or joints. ‘Aberrant honeycomb’ cells (type 2 features) are highly elongate, polygonal, or irregular ﬂat depressions of decimetre scale surrounded by walls rarely higher than 2 cm, some of which pass into long, free‐standing walls or tendrils. Thus, not all type 2 ‘honeycomb’ cells are fully enclosed.

We measured the geometry of 551 honeycomb cells and examined various rock properties (microscopic texture and fabric, mineralogy, porosity, permeability, and chemical composition) to isolate factors that control the size, shape, distribution, and pattern of the honeycombs. Our goal was to narrow potential origins of the features and to understand their formation.

The ubiquitous occurrence of sea salt in the honeycombs and scanning electron microscope evidence of physical weathering of silicates, especially micas, favours an origin for the honeycombs chieﬂy by salt weathering. Honeycombs do not form in siltstone, iron‐oxide‐impregnated sandstone, calcite‐cemented concretions, or in case‐hardened joints. Thus, salt weathering of type 1 and 2 honeycombs is not effective in very low permeability rocks.

We propose for type 1 honeycombs that seawater is drawn into micropores of the sandstone and evolves into self‐organized diffusion cells (Turing patterns). Selective evaporation at the stationary nodes of diffusion cells, which form at the same site over time, leads to the precipitation of salt, then grains spall off, and pits are formed. The deepest pits (>40 mm) formed where Turing patterns consistently formed at the same sites. Although the walls are more porous and weathered than the host sandstone, they become selectively case hardened by an unidentiﬁed component of low abundance. Initial honeycomb cell shape and gravity locally inﬂuenced type 1 honeycomb shapes.

We suggest that type 2 honeycombs develop where diffusion‐controlled Turing patterns lead to case‐hardening along linear trends; gravity and rock fabric are important locally in inﬂuencing the orientation of the walls. Only type 2 cells are forming today, suggesting recent environmental changes.

Gravity is not a fundamental control on honeycomb shape; in places it is a contributing factor. Pre‐existing depressions (quarry tool marks) have strongly inﬂuenced honeycomb shape locally. Copyright © 2004 John Wiley & Sons, Ltd.
Earthquake‐related geomorphic environment and pond sediment information
Authors: Kashiwaya Kenji , Tsuya Yoshikazu , Okimura Takashi
Published: June 2004

Shaking during the 1995 Kobe earthquake caused surface material to be more mobile in catchment areas in the Rokko Mountains, Kobe, where there are some active fault lines. As a result, there were many landslides associated with the earthquake. The sedimentation rate in a pond in the mountains increased several fold, then exponentially decreased with seasonality over several years. Six years after the earthquake there were no marked surface movements related to the earthquake, even though the sedimentation rates had increased slightly. A new steady state for the structure of the earthquake‐modiﬁed surface had evidently been reached. Copyright © 2004 John Wiley & Sons, Ltd.
Extracting the Expected Path of Monetary Policy From Futures Rates
Authors: Sack Brian
Published: June 2004

Federal funds and eurodollar futures contracts are among the most useful instruments for deriving expectations of the future path of monetary policy. However, reading policy expectations from those instruments is complicated by the presence of risk premia. This paper demonstrates how to extract the expected policy path under the assumption that risk premia are constant over time, and under a simple model that allows risk premia to vary. In the latter case, the risk premia are identified under the assumption that policy expectations level out after a long enough horizon. The results provide evidence that the risk premia on these futures contracts vary over time. The impact of this variation is fairly limited for futures contracts with short horizons, but it increases as the horizon of the contracts lengthens. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:733–754, 2004
Molecular characterization of epstein‐barr virus and oncoprotein expression in nasopharyngeal carcinoma in Korea
Authors: Jeon Yoon Kyung , Lee Bo Young , Kim Ji Eun , Lee Seung Sook , Kim Chul Woo
Published: June 2004

Background.

We evaluated the characteristics of nasopharyngeal carcinoma in Korea, including its clinical, pathologic, and molecular features, especially emphasizing on the EBV strains involved, latent membrane protein 1 (LMP1) expression, and the alterations of matrix metalloproteinase 9 (MMP9) and E‐cadherin expression.

Methods.

The presence of EBV was evaluated by EBER in situ hybridization, and the expression of LMP1, MMP9, and E‐cadherin by immunohistochemistry. The characterization of EBV type and LMP1 variant was performed by PCR.

Results.

EBER was detected in 55 of 57 cases (96%) of nonkeratinizing carcinoma (NKC) and undifferentiated carcinoma, but in only four of nine cases (44%) of squamous cell carcinoma (SCC). EBER positivity was much higher in the group with nodal metastases (p = .003). The predominant strain of EBV infection was type A (81%) and a 30‐bp deletion LMP1 variant (77%). All EBER‐positive SCCs were infected with EBV type A. LMP1 expression was detected in 36 of 59 (61%) patients with latent EBV infection and MMP9 in 41 of these 59 (69%). LMP1 positivity was much higher among the patients aged 50 years and younger. MMP9 expression was associated with LMP1 expression (p = .008), and nodal and distant metastasis (p = .019, p = .045). Loss of E‐cadherin expression was correlated with MMP9 and nodal metastasis. The survival rate was much lower in patients with a higher TNM classification, stage, and a histology of SCC. EBER positivity was associated with a better prognosis in the Kaplan‐Meier test, but had no prognostic value by Cox regression analysis. Loss of E‐cadherin expression and nodal metastasis were also correlated with local recurrence and distant metastasis.

Conclusion.

EBV type and LMP1 variant had no significant influence on the clinicopathologic properties of tumor. However, there was a tendency toward a better survival in the EBV type B group. Histology and clinical staging were the two most important prognostic factors. © 2004 Wiley Periodicals, Inc. Head Neck 26: 573–583, 2004
Nucleosomes activate NF‐κB in endothelial cells for induction of the proangiogenic cytokine IL‐8
Authors: Tanner Jerome E.
Published: June 2004

Solid tumors often exhibit regions undergoing apoptosis and necrosis, also referred to as “aponecrosis”, juxtaposed to sites of active angiogenesis. We explored whether nucleosomes resulting from aponecrosis induced the angiogenic factor IL‐8 in vascular endothelial cells. Results indicate that nucleosomes induced IL‐8. Nucleosomes increased IL‐6 and IL‐8 mRNA but not IL‐10, TNF‐α, VEGF or FGF‐2 mRNA. Induction of IL‐8 by nucleosomes in endothelial cells appeared to be the result of NF‐κB/RelA transcription factor activation. The increased expression of IL‐8 in vascular endothelial cells following nucleosome stimulation suggests that aponecrosis could play an important role in the promotion of tumor angiogenesis. © 2004 Wiley‐Liss, Inc.
Semi‐objective classification for daily synoptic systems: application to the eastern Mediterranean climate change
Authors: Alpert P. , Osetinsky I. , Ziv B. , Shafir H.
Published: June 2004

Semi‐objective classification of daily 1200 UTC synoptic systems was carried out by a discriminant‐like analysis of the National Center for Environmental Prediction–National Center for Atmospheric Research reanalysis data over the eastern Mediterranean (EM) for 1948–2000. An example for a climate change application is given by the analysis of trends in the annual frequencies of the synoptic systems. The frequencies of the mostly dry Red Sea trough (RST) systems nearly doubled since the 1960s from 50 to about 100 days per year. This explains a dominant decreasing trend of rainfall in most of the EM, along with an increase in the southern part of the EM region, when the RST is deep enough to bring tropical moisture over this area. Also, the increasing tendency towards heavier daily rainfall in spite of the general decrease in the totals may be explained by the increase in the active and stormy types of RST situations. The annual frequency of the Cyprus lows was noticed to drop slightly in 1983–98 to 26, compared with about 30 during 1967–82. The high positive correlation between the recent increase in the North Atlantic oscillation index and the pressure over most of the EM countries is linked to these tendencies in the synoptic systems. Copyright © 2004 Royal Meteorological Society
A new seasons definition based on classified daily synoptic systems: an example for the eastern Mediterranean
Authors: Alpert P. , Osetinsky I. , Ziv B. , Shafir H.
Published: June 2004

A new definition for seasons based on a synoptic classification is introduced. It uses the automatically classified daily synoptic systems. For the eastern Mediterranean (EM), the temporal distribution of the synoptic systems over 53 years enables a proper definition of the timing and duration of the cold rainy, warm dry and of the transition seasons. Comparisons with the astronomical, meteorological and the temperature‐based seasons definitions following Trenberth is performed. According to the synoptic definition proposed here and applied to the EM, the winter and summer seasons each last about 4 months (3 months and 23 days). The EM ‘synoptic summer’ and ‘synoptic winter’ defined here begin at about the earliest starting date, i.e. the meteorological start, and they end at about the latest ending date, i.e. the astronomical end. Copyright © 2004 Royal Meteorological Society
Effect of non-lasing vibro-rotational levels on the dynamics of the
Q-switched CO2 laser
Authors: Ma Tao , Gao Jin-Yue , Jiang Yun , Kang Zhi-Hui , Xu Xiao-Feng , Sherstov I V
Published: June 2004

A fast chopper is used to set up a mechanical Q-switched
CO2 laser and pulse trains of repetitively Q-switched
generation are recorded. We put special emphasis on the effect of
the non-laser vibro-rotational levels on describing the dynamic
processes of this laser. The calculated pulse waveforms based on
the vibro-rotational model are in good agreement with the
experiment.
Raman spectroscopic evaluation of molecular orientation in polysulfone
Authors: Shilton S J , Prokhorov K A , Gordeyev S A , Nikolaeva G Yu , Dunkin I R , Smith W E , Pashinin P P
Published: June 2004

In this paper, we present for the first time a Raman spectroscopic method for the determination of molecular orientation in uniaxially oriented polysulfone (PSU).
Optical filtering properties of inhomogeneous isotropic slab waveguides
Authors: Rostami A , Matloub S
Published: June 2004

Inhomogeneous optical slab or channel wave-guides are
basic alternative for realization of the passive and active
devices and systems in the full-optical engineering domain.
Usually, the exact treatment for obtaining the reflected and
transmitted light is very hard and the numerical methods are used.
In this paper, we will investigate the optical filtering
properties of the exactly solvable large set of the inhomogeneous
index of refraction profiles. We show that tuning of the
inhomogeneous media length easily can control the bandwidth of our
proposed filter.
Recombination-stimulated growth and relaxation of dislocation loops as a
mechanism of multi-pulse laser damage of semiconductors
Authors: Emel'yanov V I , Rogacheva A V
Published: June 2004

A new model of recombination-stimulated nucleation and
growth of dislocation loops in semiconductors with intense laser
generation of electron-hole pairs is developed. The model is shown
to describe experimental results on multipulse laser damage of
silicon surface
Multimode model of superradiant scattering from BEC of dilute gas
Authors: Avetisyan Yu A , Trifonov E D
Published: June 2004

The semiclassical theory for multimode model of light
scattering from Bose-Einstein condensate of dilute gas is
presented. It permits to obtain the spacial dependence of
scattering field inside the condensate and the inhomogeneous
distribution of atomic density in recoil clouds.
Continuum approach to the numerical simulation of material failure in concrete
Authors: Oliver J. , Huespe A. E. , Samaniego E. , Chaves E. W. V.
Published: June 2004

Some new aspects of the continuum strong discontinuity approach (CSDA) to model material failure in geomaterials are addressed. A new global algorithm, for tracking multiple crack lines/surfaces in 2D/3D cases is proposed. It is based on solving a simple heat conduction‐like problem accompanying the standard mechanical algorithm. A viscous perturbation method on the crack surface is also proposed to remedy the instabilities caused by mutual interactions of multiple developing cracks. A simple procedure to compute the critical time step that ensures algorithmic uniqueness is then provided. Numerical simulations of two‐ and three‐dimensional problems displaying a multi‐crack pattern are finally presented. Copyright © 2004 John Wiley & Sons, Ltd.
Three‐dimensional liquid transport in concrete cracks
Authors: Carmeliet J. , Delerue J.‐F. , Vandersteen K. , Roels S.
Published: June 2004

Cracks in concrete are measured in 3D by microfocus X‐ray computer tomography. The tomographic images are thresholded matching a characteristic of the measured crack attenuation profile. A methodology is proposed to convert the 3D measured voxel data into a network of parallel plates. The methodology is based on the determination of the aperture map and skeleton of the void space, and the segmentation of the void space in crack segments. The segmentation and network approach allows to study crack aperture and connectivity distributions of the crack. Static invasion percolation and moving front technique are used to analyse liquid flow in cracks. One‐dimensional simulations of transport in a crack with variable crack width exemplify the retardation effect of narrow passages. In 2D, the narrow passages can be by‐passed resulting in preferential flow patterns, where coarse crack zones remain unfilled. Mesh sensitivity in the network approach is studied showing a limited influence of the mesh size on the filling patterns, caused by a change of connectivity when refining the mesh. Comparison of 3D and 2D simulations indicates that flow in 2D crack sections can strongly underestimate possible fluid penetration depths. Finally the network model is validated analysing water uptake in a fractured brick sample. Copyright © 2004 John Wiley & Sons, Ltd.
Gradient enhanced thermo‐mechanical damage model for concrete at high temperatures including transient thermal creep
Authors: Pearce Chris J. , Nielsen Claus V. , Bićanić N.
Published: June 2004

A thermo‐mechanical model for concrete under transient high temperatures is presented. Particular emphasis is placed on the transient thermal creep model, which can be seen as an extension of Thelandersson's formulation, and the gradient‐enhanced damage model that has been extended here to include temperature dependency. Degradation of the material stiffness due to exposure to elevated temperatures is included via a simple thermal damage model. The model's performance is illustrated on several benchmark problems under both transient and steady state heating conditions. Copyright © 2004 John Wiley & Sons, Ltd.
A new triangular element to model inter‐laminar shear stress continuous plate theory
Authors: Chakrabarti A. , Sheikh A. H.
Published: June 2004

An efficient triangular element based on an inter‐laminar shear stress continuous plate theory is developed and applied to the analysis of composite and sandwich plates under different situations to study the performance of the element. The plate theory represents parabolic through thickness variation of transverse shear stresses where the continuity condition of these stresses are satisfied at the layer interfaces. It also satisfies transverse shear stress free condition at the top and bottom surfaces of the plate. The most attractive feature of the plate theory is that the basic unknowns are same as those used in first‐order shear deformation theory. The only problem lies with this elegant plate theory is found in its finite element implementation, as it requires C1 continuity of transverse displacement at the element interfaces. This is a well‐known problem of thin plate elements, which is also found in some other refined plate theories. Although there are some elements based on these refined plate theories but the number of such elements is very few and they possess certain drawbacks in general. Keeping these aspects in view, an attempt has been made in this study to develop a six‐noded triangular element having equal degrees of freedom at each node. Copyright © 2004 John Wiley & Sons, Ltd.
Adaptive strategies and error control for computing material forces in fracture mechanics
Authors: Heintz Per , Larsson Fredrik , Hansbo Peter , Runesson Kenneth
Published: June 2004

The concept of material forces pertains to a variation of the inverse motion map while the placement field is kept fixed. From the weak formulation of the self‐equilibrating Eshelby (material) stress tensor it turns out that the classical J‐integral formulations in fracture mechanics are just special cases due to the choice of particular weight functions. In this contribution, we discuss a posteriori error control of the material forces as part of an adaptive strategy to reduce the discretization error to an acceptable level. The data of the dual problem involves the quite non‐conventional tangent stiffness of the (material) Eshelby stress tensor with respect to a variation of the (physical) strain field. The suggested strategy is applied to the common fracture mechanics problem of a single‐edged crack, whereby different strategies for computing the J‐integral are compared. We also consider the case in which the crack edges are not parallel, i.e. a notch. Copyright © 2004 John Wiley & Sons, Ltd.
Object‐oriented hierarchical mesh refinement with CHARMS
Authors: Krysl Petr , Trivedi Abhishek , Zhu Baozhi
Published: June 2004

A new approach to the construction of adaptive approximations on finite element meshes and also in more general settings, including approximations on subdivision surfaces, had been recently proposed by Krysl, Grinspun, and Schröder. This paper outlines how the general refinement algorithms may be specialized to some common finite element discretizations in two and three dimensions, discusses the design of nested meshes, and delves into the algorithmic, design, and implementation issues in an object oriented software framework (http://hogwarts.ucsd.edu/∼pkrysl/CHARMS). Copyright © 2004 John Wiley & Sons, Ltd.
Evaluating the LCD algorithm for solving linear systems of equations arising from implicit SUPG formulation of compressible flows
Authors: Catabriga Lucia , Coutinho Alvaro L. G. A. , Franca Leopoldo P.
Published: June 2004

In this work we evaluate the performance of the left conjugate direction method recently introduced by Yuan, Golub, Plemmons and Cecílio for the solution of non‐symmetric systems of linear equations arising from the implicit semi‐discrete SUPG finite element formulation of advective–diffusive and inviscid compressible flows. We extend the original algorithm to accommodate restarts and typical element‐by‐element preconditioners. We also show how to select the first left conjugate vector to start LCD. Several problems are solved, accessing performance parameters such as number of iterations, memory requirements and CPU times, and results are compared with other algorithms, such as GMRES, TFQMR and Bi‐CGSTAB. Copyright © 2004 John Wiley & Sons, Ltd.
Stochastic inverse heat conduction using a spectral approach
Authors: Narayanan Velamur Asokan Badri , Zabaras Nicholas
Published: June 2004

An adjoint‐based functional optimization technique in conjunction with the spectral stochastic finite element method is proposed for the solution of an inverse heat conduction problem in the presence of uncertainties in material data, process conditions and measurement noise. The ill‐posed stochastic inverse problem is restated as a conditionally well‐posed L2 optimization problem. The gradient of the objective function is obtained in a distributional sense by defining an appropriate stochastic adjoint field. The L2 optimization problem is solved using a conjugate‐gradient approach. Accuracy and effectiveness of the proposed approach is appraised with the solution of several stochastic inverse heat conduction problems. Copyright © 2004 John Wiley & Sons, Ltd.
Solution of a multidimensional inverse radiation problem by means of mode reduction
Authors: Park H. M. , Sung M. C.
Published: June 2004

The Karhunen–Loève Galerkin procedure is employed to solve an inverse radiation problem of determining the time‐varying strength of a heat source, which mimics flames in a furnace, from temperature measurements in three‐dimensional participating media where radiation and conduction occur simultaneously. The inverse radiation problem is solved through the minimization of a performance function, which is expressed by the sum of square residuals between calculated and observed temperature, using a conjugate gradient method. Through the Karhunen–Loève Galerkin procedure, one can represent the system dynamics with a minimum degree of freedom, and consequently the amount of computation required in the solution of the inverse problem is reduced drastically when the present technique is adopted. Copyright © 2004 John Wiley & Sons, Ltd.
Block preconditioners for symmetric indefinite linear systems
Authors: Toh Kim‐Chuan , Phoon Kok‐Kwang , Chan Swee‐Huat
Published: June 2004

This paper presents a systematic theoretical and numerical evaluation of three common block preconditioners in a Krylov subspace method for solving symmetric indefinite linear systems. The focus is on large‐scale real world problems where block approximations are a practical necessity. The main illustration is the performance of the block diagonal, constrained, and lower triangular preconditioners over a range of block approximations for the symmetric indefinite system arising from large‐scale finite element discretization of Biot's consolidation equations. This system of equations is of fundamental importance to geomechanics. Numerical studies show that simple diagonal approximations to the (1,1) block K and inexpensive approximations to the Schur complement matrix S may not always produce the most spectacular time savings when K is explicitly available, but is able to deliver reasonably good results on a consistent basis. In addition, the block diagonal preconditioner with a negative (2,2) block appears to be reasonably competitive when compared to the more complicated ones. These observation are expected to remain valid for coefficient matrices whereby the (1,1) block is sparse, diagonally significant (a notion weaker than diagonal dominance), moderately well‐conditioned, and has a much larger block size than the (2,2) block. Copyright © 2004 John Wiley & Sons, Ltd.