bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell-Type-Dependent Effect of Transforming Growth Factor β, a Major Cytokine in Breast Milk, on Human Immunodeficiency Virus Type 1 Infection of Mammary Epithelial MCF-7 Cells or Macrophages
Authors: Moriuchi Masako , Moriuchi Hiroyuki
Published: November 2004

Breastfeeding plays a substantial role in mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1). Mammary epithelial cells, as well as macrophages and lymphocytes, are thought to serve as sources of the virus in breast milk. Soluble factors in breast milk exert various biological functions, including immune tolerance or immune modulation, and may influence milk-borne infection with HIV-1. In this study we show that transforming growth factor β (TGF-β), a major cytokine in breast milk, inhibited HIV-1 infection of mammary epithelial MCF-7 cells but enhanced that of macrophages. TGF-β downregulated the HIV-1 long terminal repeat (LTR) promoter in MCF-7 cells but upregulated it in macrophages. Stimulation with TGF-β suppressed NF-κB binding to the HIV-1 LTR in MCF-7 cells, at least in part by downregulating induced IκB kinase expression. Cell type-dependent effects of TGF-β on HIV-1 expression may play a role in milk-borne infection with HIV-1.
Identification of a Mouse Cytomegalovirus Gene Selectively Targeting CD86 Expression on Antigen-Presenting Cells
Authors: Loewendorf Andrea , Krüger Corinna , Borst Eva Maria , Wagner Markus , Just Ursula , Messerle Martin
Published: November 2004

We and others have shown that infection of dendritic cells with murine cytomegalovirus (MCMV) leads to severe functional impairment of these antigen-presenting cells (D. M. Andrews, C. E. Andoniou, F. Granucci, P. Ricciardi-Castagnoli, and M. A. Degli-Esposti, Nat. Immunol.
2:
1077-1084, 2001; S. Mathys, T. Schroeder, J. Ellwart, U. H. Koszinowski, M. Messerle, and U. Just, J. Infect. Dis.
187:
988-999, 2003). Phenotypically, reduced surface expression of costimulatory molecules and major histocompatibility complex molecules was detected. In order to identify the molecular basis for the observed effects, we generated MCMV mutants with large deletions of nonessential genes. The study was facilitated by the finding that a monocyte-macrophage cell line displayed similar phenotypic alterations after MCMV infection. By analyzing the expression of cell surface molecules on infected cells, we identified a mutant virus which is no longer able to downmodulate the expression of the costimulatory molecule CD86. Additional mutants with smaller deletions allowed us to pin down the responsible gene to a certain genomic region. RNA analysis led to the identification of the spliced gene m147.5, encoding a protein with 145 amino acids. Experiments with an m147.5 mutant revealed that the protein affects CD86 expression only, suggesting that additional MCMV genes are responsible for downmodulation of the other surface molecules. Identification of viral gene products interfering with functionally important proteins of antigen-presenting cells will provide the basis to dissect the complex interaction of CMV with these important cells and to evaluate the biological importance of these viral genes in vivo.
Bracoviruses Contain a Large Multigene Family Coding for Protein Tyrosine Phosphatases
Authors: Provost Bertille , Varricchio Paola , Arana Eloisa , Espagne Eric , Falabella Patrizia , Huguet Elisabeth , La Scaleia Raffaella , Cattolico Laurence , Poirié Marylène , Malva Carla , Olszewski Julie A. , Pennacchio Francesco , Drezen Jean-Michel
Published: November 2004

The relationship between parasitic wasps and bracoviruses constitutes one of the few known mutualisms between viruses and eukaryotes. The virions produced in the wasp ovaries are injected into host lepidopteran larvae, where virus genes are expressed, allowing successful development of the parasite by inducing host immune suppression and developmental arrest. Bracovirus-bearing wasps have a common phylogenetic origin, and contemporary bracoviruses are hypothesized to have been inherited by chromosomal transmission from a virus that originally integrated into the genome of the common ancestor wasp living 73.7 ± 10 million years ago. However, so far no conserved genes have been described among different braconid wasp subfamilies. Here we show that a gene family is present in bracoviruses of different braconid wasp subfamilies (
Cotesia congregata
, Microgastrinae, and
Toxoneuron nigriceps
, Cardiochilinae) which likely corresponds to an ancient component of the bracovirus genome that might have been present in the ancestral virus. The genes encode proteins belonging to the protein tyrosine phosphatase family, known to play a key role in the control of signal transduction pathways. Bracovirus protein tyrosine phosphatase genes were shown to be expressed in different tissues of parasitized hosts, and two protein tyrosine phosphatases were produced with recombinant baculoviruses and tested for their biochemical activity. One protein tyrosine phosphatase is a functional phosphatase. These results strengthen the hypothesis that protein tyrosine phosphatases are involved in virally induced alterations of host physiology during parasitism.
Separate Sequences in a Murine Retroviral Envelope Protein Mediate Neuropathogenesis by Complementary Mechanisms with Differing Requirements for Tumor Necrosis Factor Alpha
Authors: Peterson Karin E. , Hughes Scott , Dimcheff Derek E. , Wehrly Kathy , Chesebro Bruce
Published: November 2004

The innate immune response, through the induction of proinflammatory cytokines and antiviral factors, plays an important role in protecting the host from pathogens. Several components of the innate response, including tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein 1, interferon-inducible protein 10, and RANTES, are upregulated in the brain following neurovirulent retrovirus infection in humans and in animal models. However, it remains unclear whether this immune response is protective, pathogenic, or both. In the present study, by using TNF-α
−/−
mice we analyzed the contribution of TNF-α to neurological disease induced by four neurovirulent murine retroviruses, with three of these viruses encoding portions of the same neurovirulent envelope protein. Surprisingly, only one retrovirus (EC) required TNF-α for disease induction, and this virus induced less TNF-α expression in the brain than did the other retroviruses. Analysis of glial fibrillary acidic protein and F4/80 in EC-infected TNF-α
−/−
mice showed normal activation of astrocytes but not of microglia. Thus, TNF-α-mediated microglial activation may be important in the pathogenic process initiated by EC infection. In contrast, TNF-α was not required for pathogenesis of the closely related BE virus and the BE virus induced disease in TNF-α
−/−
mice by a different mechanism that did not require microglial activation. These results provide new insights into the multifactorial mechanisms involved in retrovirus-induced neurodegeneration and may also have analogies to other types of neurodegeneration.
Inhibition of Tumor Necrosis Factor (TNF) Signal Transduction by the Adenovirus Group C RID Complex Involves Downregulation of Surface Levels of TNF Receptor 1
Authors: Fessler Shawn P. , Chin Y. Rebecca , Horwitz Marshall S.
Published: November 2004

Adenoviruses employ multiple genes to inhibit the host antiviral responses. There is increasing evidence that these immunoregulatory genes may function either during lytic or latent infection. Adenovirus early transcription region 3 (E3) encodes at least seven proteins, five of which block the acquired or innate immune response. Previous findings from this laboratory demonstrated that the E3 proteins 10.4K and 14.5K, which form a complex in the plasma membrane, inhibit tumor necrosis factor (TNF)-induced activation of NF-κB and the synthesis of chemokines. To determine the mechanism of inhibition of these pathways by the adenovirus E3 10.4K/14.5K proteins, we have examined the effects of this viral complex on the inhibition of AP-1 and NF-κB activation by TNF and found a reduction in assembly of the TNF receptor 1 (TNFR1) signaling complex at the plasma membrane accompanied by downregulation of surface levels of TNFR1.
Gender Differences in Human Immunodeficiency Virus Type 1-Specific CD8 Responses in the Reproductive Tract and Colon following Nasal Peptide Priming and Modified Vaccinia Virus Ankara Boosting
Authors: Peacock James W. , Nordone Sushila K. , Jackson Shawn S. , Liao Hua-Xin , Letvin Norman L. , Yafal Alicia Gomez , Gritz Linda , Mazzara Gail P. , Haynes Barton F. , Staats Herman F.
Published: November 2004

Induction of mucosal anti-human immunodeficiency virus type 1 (HIV-1) T-cell responses in males and females will be important for the development of a successful HIV-1 vaccine. An HIV-1 envelope peptide, DNA plasmid, and recombinant modified vaccinia virus Ankara (rMVA) expressing the H-2Dd-restricted cytotoxic T lymphocyte P18 epitope were used as immunogens to test for their ability to prime and boost anti-HIV-1 T-cell responses at mucosal and systemic sites in BALB/c mice. We found of all prime-boost combinations tested, an HIV-1 Env peptide subunit mucosal prime followed by systemic (intradermal) boosting with rMVA yielded the maximal induction of gamma interferon (IFN-γ) spot-forming cells in the female genital tract and colon. However, this mucosal prime-systemic rMVA boost regimen was minimally immunogenic for the induction of genital, colon, or lung anti-HIV-1 T-cell responses in male mice. We determined that a mucosal Env subunit immunization could optimally prime an rMVA boost in female but not male mice, as determined by the magnitude of antigen-specific IFN-γ responses in the reproductive tracts, colon, and lung. Defective mucosal priming in male mice could not be overcome by multiple mucosal immunizations. However, rMVA priming followed by an rMVA boost was the optimal prime-boost strategy for male mice as determined by the magnitude of antigen-specific IFN-γ responses in the reproductive tract and lung. Thus, prime-boost immunization strategies able to induce mucosal antigen-specific IFN-γ responses were identified for male and female mice. Understanding the cellular and molecular basis of gender-determined immune responses will be important for optimizing induction of anti-HIV-1 mucosal immune responses in both males and females.
Human Cytomegalovirus-Specific CD4
+
-T-Cell Cytokine Response Induces Fractalkine in Endothelial Cells
Authors: Bolovan-Fritts Cynthia A. , Trout Rodney N. , Spector Stephen A.
Published: November 2004

Cytomegalovirus (CMV) infection has been linked to inflammation-related disease processes in the human host, including vascular diseases and chronic transplant rejection. The mechanisms through which CMV affects the pathogenesis of these diseases are for the most part unknown. To study the contributing role of the host immune response to CMV in these chronic inflammatory processes, we examined endothelial cell interactions with peripheral blood mononuclear cells (PBMC). Endothelial cultures were monitored for levels of fractalkine induction as a marker for initiating the host inflammatory response. Our results demonstrate that in the presence of CMV antigen PBMC from normal healthy CMV-seropositive donors produce soluble factors that induce fractalkine in endothelial cells. This was not observed in parallel assays with PBMC from seronegative donors. Examination of subset populations within the PBMC further revealed that CMV antigen-stimulated CD4
+
T cells were the source of the factors, gamma interferon and tumor necrosis factor alpha, driving fractalkine induction. Direct contact between CD4
+
cells and the endothelial monolayers is required for this fractalkine induction, where the endothelial cells appear to provide antigen presentation functions. These findings indicate that CMV may represent one member of a class of persistent pathogens where the antigen-specific T-cell response can result in the induction of fractalkine, leading to chronic inflammation and endothelial cell injury.
Comprehensive Cross-Clade Neutralization Analysis of a Panel of Anti-Human Immunodeficiency Virus Type 1 Monoclonal Antibodies
Authors: Binley James M. , Wrin Terri , Korber Bette , Zwick Michael B. , Wang Meng , Chappey Colombe , Stiegler Gabriela , Kunert Renate , Zolla-Pazner Susan , Katinger Hermann , Petropoulos Christos J. , Burton Dennis R.
Published: November 2004

Broadly neutralizing monoclonal antibodies (MAbs) are potentially important tools in human immunodeficiency virus type 1 (HIV-1) vaccine design. A few rare MAbs have been intensively studied, but we still have a limited appreciation of their neutralization breadth. Using a pseudovirus assay, we evaluated MAbs from clade B-infected donors and a clade B HIV+plasma against 93 viruses from diverse backgrounds. Anti-gp120 MAbs exhibited greater activity against clade B than non-B viruses, whereas anti-gp41 MAbs exhibited broad interclade activity. Unexpectedly, MAb 4E10 (directed against the C terminus of the gp41 ectodomain) neutralized all 90 viruses with moderate potency. MAb 2F5 (directed against an epitope adjacent to that of 4E10) neutralized 67% of isolates, but none from clade C. Anti-gp120 MAb b12 (directed against an epitope overlapping the CD4 binding site) neutralized 50% of viruses, including some from almost every clade. 2G12 (directed against a high-mannose epitope on gp120) neutralized 41% of the viruses, but none from clades C or E. MAbs to the gp120 V3 loop, including 447-52D, neutralized a subset of clade B viruses (up to 45%) but infrequently neutralized other clades (≤7%). MAbs b6 (directed against the CD4 binding site) and X5 (directed against a CD4-induced epitope of gp120) neutralized only sensitive primary clade B viruses. The HIV+plasma neutralized 70% of the viruses, including some from all major clades. Further analysis revealed five neutralizing immunotypes that were somewhat associated with clades. As well as the significance for vaccine design, our data have implications for passive-immunization studies in countries where clade C viruses are common, given that only MAbs b12 and 4E10 were effective against viruses from this clade.
Biological Significance of the Second Receptor Binding Site of Newcastle Disease Virus Hemagglutinin-Neuraminidase Protein
Authors: Bousse Tatiana L. , Taylor Garry , Krishnamurthy Sateesh , Portner Allen , Samal Siba K. , Takimoto Toru
Published: November 2004

The paramyxovirus hemagglutinin-neuraminidase (HN) is a multifunctional protein responsible for attachment to receptors containing sialic acid, neuraminidase (NA) activity, and the promotion of membrane fusion, which is induced by the fusion protein. Analysis of the three-dimensional structure of Newcastle disease virus (NDV) HN protein revealed the presence of a large pocket, which mediates both receptor binding and NA activities. Recently, a second sialic acid binding site on HN was revealed by cocrystallization of the HN with a thiosialoside Neu5Ac-2-
S
-α(2,6)Gal1OMe, suggesting that NDV HN contains an additional sialic acid binding site. To evaluate the role of the second binding site on the life cycle of NDV, we rescued mutant viruses whose HNs were mutated at Arg516, a key residue that is involved in the second binding site. Loss of the second binding site on mutant HNs was confirmed by the hemagglutination inhibition test, which uses an inhibitor designed to block the NA active site. Characterization of the biological activities of HN showed that the mutation at Arg516 had no effect on NA activity. However, the fusion promotion activity of HN was substantially reduced by the mutation. Furthermore, the mutations at Arg516 slowed the growth rate of virus in tissue culture cells. These results suggest that the second binding site facilitates virus infection and growth by enhancing the fusion promotion activity of the HN.
Reevaluation of the Virulence of Prototypic Strain 15 of Pneumonia Virus of Mice
Authors: Krempl Christine D. , Collins Peter L.
Published: November 2004

Prototypic strain 15 of pneumonia virus of mice (PVM) has been described as being nonpathogenic in mice, in contrast to the mouse-passaged, highly virulent strain J3666. Previous sequence analysis also indicated that strain 15 encodes an attachment G protein that is truncated at the amino terminus, which for the amino terminally anchored protein deletes the cytoplasmic tail. However, we found that PVM strain 15 obtained from the American Type Culture Collection was highly virulent in mice and was essentially indistinguishable on that basis from strain J3666. Sequence analysis showed that this preparation of virus encodes a G protein with an intact cytoplasmic tail: the truncated predicted protein in the previous sequence appeared to be due to a single nucleotide insertion that disrupted the upstream end of the open reading frame and shifted the translational start site to the next downstream AUG. Taken together, the two studies indicate that strain 15 is an inherently virulent strain but that a nonpathogenic variant that was generated during passage in vitro and encodes a truncated G protein exists. Interestingly, the majority sequence of strain J3666 was found to encode a G protein with an extended cytoplasmic tail, suggesting that there is the potential for considerable plasticity in the cytoplasmic tail of the G protein of PVM.
Raf-Induced Vascular Endothelial Growth Factor Augments Kaposi's Sarcoma-Associated Herpesvirus Infection
Authors: Hamden Khalief E. , Ford Patrick W. , Whitman Audy G. , Dyson Ossie F. , Cheng Shi-Yuan , McCubrey James A. , Akula Shaw M.
Published: November 2004

Recombinant green fluorescent protein encoding Kaposi's sarcoma-associated herpesvirus (rKSHV.152) infection of β-estradiol stimulated human foreskin fibroblasts (HFF) or HFF/ΔB-Raf
[FF]
:ER (expressing a weaker form of B-Raf) could be enhanced to levels comparable to that of HFF/ΔB-Raf
[DD]
:ER cells by pretreating cells with soluble vascular endothelial growth factor (VEGF). Conversely, VEGF expression and infection efficiency typically observed in β-estradiol stimulated HFF/ΔB-Raf
[DD]
:ER cells could be lowered significantly by treating with VEGF small interfering RNA. In addition, we observed enhancement of the KSHV infection in HFF cells transfected with human VEGF
121
. These results confirm the ability of Raf-induced VEGF to augment KSHV infection of cells.
RNA Degradation Induced by the Herpes Simplex Virus vhs Protein Proceeds 5′ to 3′ In Vitro
Authors: Perez-Parada Jorge , Saffran Holly A. , Smiley James R.
Published: November 2004

The herpes simplex virus virion host shutoff protein (vhs) is an mRNA-specific RNase that contributes to shutoff of host protein synthesis. We show here that vhs-induced mRNA decay proceeds 5′ to 3′ in an in vitro assay system derived from rabbit reticulocyte lysate.
FLAT BACKTRACKING PROLOG FOR DATABASES: A FORMAL SEMANTICS, THE COMPUTATIONAL COMPLEXITY AND THE EXPRESSIBILITY
Authors: MUSIKAEV ILMIR KH. , TAITSLIN MIKHAIL A.
Published: November 2004

In this paper we propose a description of the class PTIME in terms of the computer language PROLOG. We also give a similar description for the classes PSPACE and EXPTIME.
WHAT IS THE LOGIC OF PARALLEL PROCESSING?
Authors: HINTIKKA JAAKKO , SANDU GABRIEL
Published: November 2004

We can associate with each consistent formula F of first-order logic a computing device as its representation. This computing device is one which will calculate the Skolem functions of F (for a denumerable domain). When two such devices are operating in parallel, the resulting architecture does not necessarily represent any ordinary first-order formula, but it will represent a formula in independence-friendly (IF) logic, which hence can be considered as a true logic of parallel processing. In order to preserve representability by a digital automaton (Turing machine), a nonstandard (constructivistic) interpretation of the logic in question has to be adopted. It is obtained by restricting the Skolem functions available to verify a formula F to recursive ones, as in the Gödel’s Dialectica interpretation.
ON HELPING AND INTERACTIVE PROOF SYSTEMS
Authors: ARVIND V. , KÖBLER J. , SCHULER R.
Published: November 2004

We investigate the complexity of honest provers in interactive proof systems. This corresponds precisely to the complexity of oracles helping the computation of robust probabilistic oracle machines. We obtain upper bounds for languages in FewEXP and for sparse sets in NP. Further, interactive protocols with provers that are reducible to sets of low information content are considered. Specifically, if the verifier communicates only with provers in P/poly, then the accepted language is low for [Formula: see text]. In the case that the provers are polynomial-time reducible to log*-sparse sets or to sets in strong-P/log then the protocol can be simulated by the verifier even without the help of provers. As a consequence we obtain new collapse results under the assumption that intractable sets reduce to sets with low information content.
A NEW TYPE OF PUSHDOWN AUTOMATA ON INFINITE TREES
Authors: PENG WUXU , IYER S. PURUSHOTHAMAN
Published: November 2004

In this paper we consider pushdown automata on infinite trees with empty stack as the accepting condition (ω-EPDTA). We provide the following regarding ω-EPDTA: (a) its relationship to other Pushdown automata on infinite trees, (b) a Kleene-Closure theorem and (c) a single exponential time algorithm for checking emptiness. We demonstrate the usefulness of ω-EPDTA through two example applications: defining the temporal uniform inevitability property and specifying a context-free process with unbounded state space, both of which cannot be defined and/or specified by the classical finite state automata on infinite trees. We also discuss the relevance of the results presented here to model-checking.
ELEMENTAL ANALYSIS OF ANCIENT CHINESE INK STICKS BY PIXE
Authors: KOHNO M. , YOSHIDA K. , MORITANI K. , NAITO M. , ENAMI K. , MAEDA H.
Published: November 2004

Four ancient Chinese ink sticks were analyzed by PIXE. One sample is estimated to belong to the Ming Dynasty period(1368–1644). Three others including a red one belong to the Ching Dynasty period(1646–1912). Trace elements such as Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Br, Sr, Pb were detected from black Chinese ink sticks. From red one, Si, S, Cl, Ca. Cr, Fe, Cu, Sr, Mo, Ba, Hg, Pb were detected. These trace elements show the materials or making processes of those sticks and every specimen has its own characteristics. At the same time, some pieces of Japanese paper and those stained with Chinese ink had been analyzed. These results show that the characteristics of ink upon paper can be determined by PIXE.
VERTICAL BEAM IN-AIR PIXE SYSTEM AT CYRIC
Authors: IWASAKI S. , ISHII K. , YOSHIZAKI K. , FUKUDA H. , MUROZONO K. , INOUE J. , KITAMURA M. , YOKOTA H. , IWATA Y. , ORIHARA H.
Published: November 2004

Newly installed vertical-beam in-air PIXE system at CYRIC (Cyclotron and Radioisotope Center, Tohoku University) and some results of experiments performed for a year were described. Three different types of samples: thick metal plate samples, living root-tips of a plant and solutions have been measured successfully in the system.
QUANTITATIVE ANALYSIS OF POWDER SAMPLE (SOIL AND CITY ASH)
Authors: FUTATSUGAWA S. , HATAKEYAMA S. , SAITOU Y. , SERA K.
Published: November 2004

Quantitative analysis of powder sample, soil, ash and so on, which consists of rich heavy metal elements that are not decomposed easily with acid or alkali was attempted. Usually, powder sample was ground with an agate mortar, mixed with binding material cellulose and pelletized for quantitative PIXE analysis. However, the resulting pellet target is thick. Accordingly, when heavy elements are included in sample, it gives effect on PIXE spectrum. Namely, matrix effect arises on it. So firstly, a fixed quantity of molybdenum was added into sample and mixed as standard material in order to determine the concentration of the most typical element, iron included in sample. Then the mixed powder were pelletized and analyzed to determine the concentration of iron. Next, original powder sample was pushed on a backing film to make thin target, and the thin target was analyzed as internal standard of determined iron by ordinary PIXE analysis method. In the result, concentrations of major elements of powder sample were determined quantitatively.
FOX-ARTIN ARC AND CONSTRUCTING KLEINIAN GROUPS ACTING ON S3 WITH LIMIT SET A WILD CANTOR SET
Authors: GUSEVSKII NIKOLAY , KLIMENKO HELEN
Published: November 2004

We construct purely loxodromic, geometrically finite, free Kleinian groups acting on S3 whose limit sets are wild Cantor sets. Our construction is closely related to the construction of the wild Fox–Artin arc.
MICRODIFFERENTIAL EQUATIONS WITH ISOTROPIC INTERSECTIONS
Authors: UCHIKOSHI KEISUKE
Published: November 2004

For some weakly hyperbolic microdifferential equations we show that the propagation of the singularity is decided by the symplectic structure of their characteristic varieties.
VARIATIONAL PROBLEMS OF CERTAIN FUNCTIONALS
Authors: DUC DUONG MINH
Published: November 2004

We get the existence and regularity of minimizers of certain functionals, which may be degenerate and have non-polynomial growth. Applying these results we can find exponentially harmonic maps in every homotopy class of maps from a connected Riemannian C4-manifold into [Formula: see text], where [Formula: see text] is a compact Riemannian C4-manifold.
ON THE CALABI ENERGY OF EXTREMAL KÄHLER METRICS
Authors: HWANG ANDREW D.
Published: November 2004

Fix a positive (1, 1)-class on a compact Kählerian manifold. Given a Kähler form representing this class, define its Calabi energy to be the L2-norm of its scalar curvature. This note proves that a critical metric for the Calabi energy, if any, is a global minimum among representatives of the chosen class, and that the critical value is determined a priori by the Kähler class. This answers affirmatively two questions of Calabi ([2, p. 99]).
A MULTILEVEL FUSION APPROACH TO OBJECT IDENTIFICATION IN OUTDOOR ROAD SCENES
Authors: MURINO VITTORIO , REGAZZONI CARLO S. , FORESTI GIAN LUCA , VERNAZZA GIANNI
Published: November 2004

The task of object identification is fundamental to the operations of an autonomous vehicle. It can be accomplished by using techniques based on a Multisensor Fusion framework, which allows the integration of data coming from different sensors. In this paper, an approach to the synergic interpretation of data provided by thermal and visual sensors is proposed. Such integration is justified by the necessity for solving the ambiguities that may arise from separate data interpretations.

The architecture of a distributed Knowledge-Based system is described. It performs an Intelligent Data Fusion process by integrating, in an opportunistic way, data acquired with a thermal and a video (b/w) camera. Data integration is performed at various architecture levels in order to increase the robustness of the whole recognition process. A priori models allow the system to obtain interesting data from both sensors; to transform such data into intermediate symbolic objects; and, finally, to recognize environmental situations on which to perform further processing. Some results are reported for different environmental conditions (i.e. a road scene by day and by night, with and without the presence of obstacles).
A NEW STRUCTURAL TECHNIQUE FOR RECOGNIZING PRINTED ARABIC TEXT
Authors: AL-SADOUN HUMOUD B. , AMIN ADNAN
Published: November 2004

This paper proposes a new structural technique for Arabic text recognition. The technique can be divided into five major steps: (1) preprocessing and binarization; (2) thinning; (3) binary tree construction; (4) segmentation; and (5) recognition. The advantage of this technique is that its execution does not depend on either the font or size of character. Thus, this same technique might be utilized for the recognition of machine or hand printed text.

The relevant algorithm is implemented on a microcomputer. Experiments were conducted to verify the accuracy and the speed of this algorithm using about 20,000 subwords each with an average length of 3 characters. The subwords used were written using different fonts. The recognition rate obtained in the experiments indicated an accuracy of 93.38 % with a speed of 2.7 characters per second.
A DESIGN METHODOLOGY FOR VERY LARGE ARRAY PROCESSORS—PART 1: GIPOP PROCESSOR ARRAY
Authors: VENKATESWARAN N. , PATTABIRAMAN S. , DEVANATHAN R. , KUMARAN B. , AHMED ASHRAF , NARAYANAN SANKARA
Published: November 2004

Very Large Array Processors (VLAP) will be the need of the future for solving computationally intense Very Large Problems (VLP) common in pattern recognition, image processing and other related areas of digital signal processing. Design methodology of such VLAPs for massively parallel dedicated/general purpose applications is highly complex. Two companion papers (Part 1 and Part 2) on VLAP are presented in this issue. In Part 1, we propose a VLAP called Reconfigurable GIPOP Processor Array (RGPA). The RGPA is made up of high performance processing elements called the Generalized Inner Product Outer Product (GIPOP) processor. Unlike the traditional special/general purpose processors, ours has a totally different and new architecture and organization involving higher level functional units to match with the complex computational structures of numeric algorithms and suitable for massively parallel processing. We also present a strategy for mapping VLPs on VLAPs. In Part 2, we propose a novel VLSI design methodology for implementing cost effective and very high performance processors meant for special purpose applications and in particular, for VLAPs.
A FAST PATTERN-MATCHING ALGORITHM ON MODULAR MESH-CONNECTED COMPUTERS WITH MULTIPLE BUSES
Authors: CHUNG KUO-LIANG
Published: November 2004

Given a pattern of length m and a text of length n, commonly m≪n, this paper presents a randomized parallel algorithm for pattern matching in O(n1/10) (=O(n1/10+(n−m)1/10)) time on a newly proposed n3/5×n2/5 modular meshconnected computers with multiple buses. Furthermore, the time bound of our parallel algorithm can be reduced to O(n1/11) if fewer processors are used.
TIME-OPTIMAL DIGITAL GEOMETRY ALGORITHMS ON MESHES WITH MULTIPLE BROADCASTING
Authors: BOKKA V. , GURLA H. , OLARIU S. , SCHWING J.L. , STOJMENOVIĆ I.
Published: November 2004

The main contribution of this work is to show that a number of digital geometry problems can be solved elegantly on meshes with multiple broadcasting by using a time-optimal solution to the leftmost one problem as a basic subroutine. Consider a binary image pretiled onto a mesh with multiple broadcasting of size [Formula: see text] one pixel per processor. Our first contribution is to prove an Ω(n1/6) time lower bound for the problem of deciding whether the image contains at least one black pixel. We then obtain time lower bounds for many other digital geometry problems by reducing this fundamental problem to all the other problems of interest. Specifically, the problems that we address are: detecting whether an image contains at least one black pixel, computing the convex hull of the image, computing the diameter of an image, deciding whether a set of digital points is a digital line, computing the minimum distance between two images, deciding whether two images are linearly separable, computing the perimeter, area and width of a given image. Our second contribution is to show that the time lower bounds obtained are tight by exhibiting simple O(n1/6) time algorithms for these problems. As previously mentioned, an interesting feature of these algorithms is that they use, directly or indirectly, an algorithm for the leftmost one problem recently developed by one of the authors.
TWO METHODOLOGIES TO IMPLEMENT 3D THINNING ALGORITHMS ON DISTRIBUTED MEMORY MACHINES
Authors: MARION-POTY VIRGINIE
Published: November 2004

Our goal is to implement skeletonization algorithms on distribution memory mechines. This implementation is not trivial, because we cannot apply locally thinning operators based on 26-neighborhood, sequentially or simultaneously on all the points of the image. After summarizing the problem, we describe two methodologies to implement these algorithms on MIMD machines, one based on the decomposition of the thinning operator into sub-operators, and the other based on the decomposition of the study domain (image) into sub-domains.
BASIC PUZZLE LANGUAGES
Authors: SUBRAMANIAN K.G. , SIROMONEY R. , DARE V.R. , SAOUDI A.
Published: November 2004

The emptiness problem for non-overlapping Basic puzzle grammars is shown to be decidable. An alternate proof of the decidability of the non-overlapping feature for basic puzzle grammars is given. Hierarchy among the various classes of puzzle languages is also established.
COOPERATING SYSTEMS OF THREE-WAY, TWO-DIMENSIONAL FINITE AUTOMATA
Authors: WANG YUE , INOUE KATSUSHI , TAKANAMI ITSUO
Published: November 2004

This paper introduces a cooperating system of three-way, two-dimensional finite automata (CS-TR2-FA) which is a restricted version of a cooperating system of four- way, two-dimensional finite automata (CS-2-FA), and mainly investigates several fundamental properties of this system as a two-dimensional language acceptor whose input tapes are restricted to square ones. We show that

(1) CS-TR2-FA’s are equivalent in accepting power to three-way, two-dimensional simple multihead finite automata,

(2) CS-2-FA’s are more powerful than CS-TR2-FA’s,

(3) £[CS-TR2-DFA(k)S] ⊊ £[CS-TR2-NFA(k)S],

(4) ⋃1≤k<∞ £[CS-TR2-DFA(k)S] ⊊ ⋃1≤k<∞ £[CS-TR2-NFA(k)S], and

(5) £[CS-TR2-DFA(k)S] (£[CS-TR2-NFA(k)S]) ⊊ £[CS-TR2-DFA(k+1)S] (£[CS-TR2-NFA(k+1)S]),

where £[CS-TR2-DFA(k)S] (£[CS-TR2-NFA(k)S]) denotes the class of sets of square input tapes accepted by CS-TR2-FA’s which consist of k deterministic (non-deterministic) finite automata.
HIDDEN MARKOV MODELS IN TEXT RECOGNITION
Authors: ANIGBOGU J.C. , BELAÏD A.
Published: November 2004

A multi-level multifont character recognition is presented. The system proceeds by first delimiting the context of the characters. As a way of enhancing system performance, typographical information is extracted and used for font identification before actual character recognition is performed. This has the advantage of sure character identification as well as text reproduction in its original form. The font identification is based on decision trees where the characters are automatically arranged differently in confusion classes according to the physical characteristics of fonts.

The character recognizers are built around the first and second order hidden Markov models (HMM) as well as Euclidean distance measures. The HMMs use the Viterbi and the Extended Viterbi algorithms to which enhancements were made. Also present is a majority-vote system that polls the other systems for “advice” before deciding on the identity of a character. Among other things, this last system is shown to give better results than each of the other systems applied individually.

The system finally uses combinations of stochastic and dictionary verification methods for word recognition and error-correction.
SPECIFIC SAFETY ASPECTS OF ELECTRIC ROAD VEHICLE TRACTION SYSTEMS
Authors: VAN DEN BOSSCHE P.
Published: November 2004

Due to their beneficial effect on environment in urban traffic, electric vehicles are an important factor for the improvement of traffic and more particularly for a healthier living environment. Electric vehicles however represent a completely different technology compared with internal combustion engines. This means that new safety hazards, mainly related to the characteristics of high-power electric equipment, may be present.

The electric vehicle system will be designed to operate safely in all conditions; a number of specific problems will be treated, concentrating on aspects of vehicle behaviour which are typical for electric vehicles. At this moment the standards and official regulations concerning electric road vehicles are not very clearly defined. The existing documents and standards are far from harmonised, and they cover a vehicle in full technological evolution. Another aspect is the psychological awareness of these "new" risks: the presence of high voltages or of battery chemicals may be used as an argument against electric vehicles; the fact that internal-combustion-engined vehicles present large risks too is often overlooked, since people get accustomed to the danger.
ON RELIABILITY ANALYSIS OF CHORDAL RINGS
Authors: NAYAK AMIYA , SANTORO NICOLA
Published: November 2004

A common technique to improve the reliability of loop (or ring) networks is by introducing link redundancy; that is, by providing several alternative paths for communication between pairs of nodes. With alternate paths between nodes, the network can now sustain several node and link failures by bypassing the faulty components. However, faults occurring at strategic locations in a ring can prevent the computation by disrupting I/O operations, blocking the flow of information, or even segmenting the structure into pieces which can no longer be suitable for any practical purpose.

An extensive characterization of fault-tolerance in ring topologies is given in this paper. This characterization augments the results known in the literature to date. The characterization has revealed several properties which describe the problem of constructing subrings and linear arrays in the presence of node failures in the original ring for a specified link configuration. Also in this paper, bounds are established on the degree of fault tolerance achievable in a redundant loop network, with a given degree of redundancy, when performing a computation that requires a minimal number of operational nodes. Also the bounds on the size of the problems guaranteed to be solved in the presence of a given number of faults in the network are derived.
AN EXTENDED FUZZY CLUSTERING ALGORITHM AND ITS APPLICATION
Authors: KIM SU HWAN , KIM SEON WOOK , RHEE TAE WON
Published: November 2004

For data analyses, it is very important to combine data with similar attribute values into a categorically homogeneous subset, called a cluster, and this technique is called clustering. Generally crisp clustering algorithms are weak in noise, because each datum should be assigned to exactly one cluster. In order to solve the problem, a fuzzy c-means, a fuzzy maximum likelihood estimation, and an optimal fuzzy clustering algorithms in the fuzzy set theory have been proposed. They, however, require a lot of processing time because of exhaustive iteration with an amount of data and their memberships. Especially large memory space results in the degradation of performance in real-time processing applications, because it takes too much time to swap between the main memory and the secondary memory. To overcome these limitations, an extended fuzzy clustering algorithm based on an unsupervised optimal fuzzy clustering algorithm is proposed in this paper. This algorithm assigns a weight factor to each distinct datum considering its occurrence rate. Also, the proposed extended fuzzy clustering algorithm considers the degree of importances of each attribute, which determines the characteristics of the data. The worst case is that the whole data has an uniformly normal distribution, which means the importance of all attributes are the same. The proposed extended fuzzy clustering algorithm has better performance than the unsupervised optimal fuzzy clustering algorithm in terms of memory space and execution time in most cases. For simulation the proposed algorithm is applied to color image segmentation. Also automatic target detection and multipeak detection are considered as applications. These schemes can be applied to any other fuzzy clustering algorithms.
SLIDING MODE DESIGN OF CONTROL AND MODULATOR ELECTRONICS FOR POWER CONVERTERS
Authors: SILVA J. FERNANDO
Published: November 2004

This paper presents state-of-the-art application of Sliding Mode Control theory, to improve the performance and to integrate the modulator and control electronics design of power converters. This approach eliminates conventional PWM modulators and loop linear PI regulators, reducing the converter complexity, weight and volume, which increases its power density figure. Sliding Mode Control techniques are used to obtain, from the controllability canonical system model, the control law, a linear combination of state variable errors and its derivatives, whose implementation is a simple circuit, that directly generates the drive pulses for the semiconductors. The commutation strategy implements a power converter with better performances than conventional PWM controlled ones, faster response and robustness concerning circuit parameter variations and operating conditions. This non linear control approach provides zero steady-state error and, by the subtle use of limiters, short circuit ouput current limitation. Using a simple 3 level clock, it is also shown how to obtain a sliding mode controller with constant switching frequency and zero steady-state error.
AN AREA EFFICIENT CURRENT LIMITER FOR AUTOMOTIVE IC: ANALYSIS AND DESIGN
Authors: CALÍ G. , PALMISANO G. , PALUMBO G. , AIELLO N.
Published: November 2004

A current limiter is proposed which uses a compensation circuit providing accurate stability without requiring a large compensation capacitor. Thanks to the use of an enhanced Miller effect, an equivalent 4 nF compensation capacitor was achieved while using only a 100 pF capacitor and a low-area single-stage amplifier.
DESIGN OF A SERIES RESONANT CONVERTER WITH MULTIPLE OUTPUT LOAD
Authors: SCHLENK MANFRED
Published: November 2004

During the last few years, a variety of circuit topologies have been developed for resonant converters. Regarding the European mains voltages push-pull converter topologies should primarily be used because of the lower blocking voltages of the switches in this type of converter. To ensure low dynamic losses of the primary switching devices at high operating voltages, ZVS-control should be adopted.

This paper discusses the choice of component values for such a converter as well as the influence of the output load circuit on the behavior of the converter. Further the design of a so-called "resonant transformer" will be presented.
THE CONNECTION OF CONVERTERS INSTEAD OF SEMICONDUCTOR POWER DEVICES — A HIGH PERFORMANCE SOLUTION FOR THE MVA RANGE OF POWER COMVERTERS
Authors: MATAKAS LOURENCO , BURLACU CATALIN , MASADA EISUKE
Published: November 2004

Recently, there is an increased demand for high power, high performance converters for power system applications, motor drives, etc. The low switching frequency of the existing semiconductor power devices poses a severe limitation that can be overcome by the use of interconnected smaller power converters (multiconverter) with appropriate control. This paper gives an overview of the state of the art of multiconverters, followed by a comparison based on analytically calculated values of the spectra, RMS and peak values of their ripple currents, and the peak values of the transformer's flux. Special attention has been given to show that the transformerless parallel connection of converters is feasible and offers features such as simplicity, gracefully degrading operating, high reliability, easy expandability and easy maintenance.
MODELING AND SIMULATION OF CONVERTER SYSTEMS PART I: METHODS, MODELS AND TECHNIQUES
Authors: SZCZESNY ROMUALD , RONKOWSKI MIECZYSLAW
Published: November 2004

In this paper a critical analysis of the methods, models and techniques applied in modeling and simulation programs of converter systems is presented. The three principal components of the converter system, i.e. converter, electrical machine and control are considered. Different approaches to modeling of power semiconductor elements are described. A general switch model and the approach, based on the Petri net, to development of switch macromodel is presented. Electrical machine modeling based on its multiport dynamic network representation are considered, and chosen as adequate for simulations of converter/machine interactions. A basic structure and features of a general-purpose simulation program are considered. Pertinent features for its five basic stages, i.e. input/pre-processing, description of component models, equation formulation, numerical solution and output/post-processing is developed. Theoretical considerations presented in this paper, should enable, depending on a given problem to be solved, both the correct development of a special program or a rational choice of a general purpose simulation program. The practical implementation of the described methods, models and techniques into a general purpose simulation program, particularly into a TCAD package, is the topic of a companion paper.
SINGLE-LOOP CURRENT-MODE CONTROL OF A PWM BOOST DC-TO-DC CONVERTER WITH A NON-SYMMETRIC PHASE CONTROLLER
Authors: KAZIMIERCZUK MARIAN K. , GEISE ROBERT S.
Published: November 2004

An extensive small-signal analysis of a single-loop current-mode control strategy for a pulse-width-modulated (PWM) boost DC-to-DC power converter operating in continuous conduction mode (CCM) is proposed using a new non-symmetric phase controller. To model the boost power stage, a linear circuit model is used which includes all parasitic components such as the equivalent series resistance (ESR) of the filter capacitor, the ESR of the inductor, the transistor ON-resistance, and the diode forward resistance and offset voltage. A boost power stage design example gives component design equations and will serve to illustrate the closed-loop converter design. A design procedure for the new non-symmetric phase controller is presented. Open-loop and closed-loop circuit models and transfer functions are derived for the boost PWM converter and illustrated by Bode plots. An approach is presented for simplifying closed-loop transfer functions, using Euler's identity, into a format which is conducive to modeling in any high level programming language on a personal computer. Bode plots are obtained using a data analysis software package Axum 3.0 which combines a programming language, spread-sheet, and publication quality technical graphics. The proposed control scheme directly controls the inductor current and indirectly controls the load current and output voltage. The closed-loop transfer functions of the proposed control scheme do not contain a righthalf plane (RHP) zero, in contrast to the closed-loop transfer functions of a single-loop voltage-mode control scheme. The absence of the RHP zero provides better stability by making it easier to obtain large or specified gain and phase margins.
ADVANCED POWER ELECTRONICS FOR REDUCING MAINS POLLUTION — ACTIVE POWER FILTERS AND OPTIMIZED UTILITY INTERFACES
Authors: HÄFNER J. , AREDES M. , HEUMANN K.
Published: November 2004

Rapid advances in turn-off semiconductor elements offer new opportunities for reactive power compensation and reduction of harmonics in energy supply systems. Non-linear consumers and also solid state power electronic equipment like diode rectifiers and thyristor converters disturb the utility voltage waveform by injecting harmonic currents into the utility grid. Their need of reactive power results in higher line currents and thereby in an increase of the rated power of the supply system. Active power filters can be used to compensate the harmonic currents, to balance unbalanced systems and to provide reactive power to the load with small storage elements. Optimized utility interfaces are controlled to ensure sinusoidal input currents of the load with unity power factor. Both, the investigated active power filter as well as the optimized utility interface are based on a four-quadrant switch-mode voltage source inverter.