bluuebunny/crossref_metadata_2025 huggingface dataset:
DYNAMICS OF SUPER-GAUSSIAN SOLITONS IN BIREFRINGENT OPTICAL FIBERS
Authors: BISWAS ANJAN
Published: May 2003

The variational principle is employed to obtain the parameter dynamics of a super-Gaussian chirped soliton that propagates through birefringent optical fibers and is governed by the dispersion-managed vector nonlinear Schrödinger's equation. The waveform deviates from that of a classical soliton. The periodically changing strong chirp of such a soliton reduces the effective nonlinearity that is necessary for balancing the local dispersion. This study is extended to obtain the adiabatic evolution of the parameters of such a soliton in presence of perturbation terms.
NONLINEAR ABSORPTION AND OPTICAL LIMITING IN SOLUTIONS OF SOME RARE EARTH SUBSTITUTED PHTHALOCYANINES
Authors: UNNIKRISHNAN K. P. , THOMAS JAYAN , PAUL BINOY , KURIAN ACHAMMA , GOPINATH PRAMOD , NAMPOORI V. P. N. , VALLABHAN C. P. G.
Published: May 2003

Effective nonlinear absorption coefficient, β eff , of solutions of some rare earth substituted phthalocyanines (viz: Sm(Pc)2, Eu(Pc)2 and LaPc) was measured using open aperture Z-scan technique under nanosecond pulse excitation at 532 nm. The effect of nonlinear absorption on optical limiting in these samples was also investigated. Both nonlinear absorption and optical limiting phenomena in these samples are attributed to sequential two-photon absorption (STPA) process.
COUPLED BRIGHT SOLITONS IN A DOUBLE MODE OPTICAL FIBER
Authors: NUSANTARA T. , SOEWONO E.
Published: May 2003

A double-mode solution in an optical fiber is described, in the common approximation, by a coupled set of NLS equation, CNLS. This set is completely integrable only if the coefficients (dispersion, nonlinear and cross-phase) satisfy specific relations. Using a generalization of Hirota's formalism, we will show that coupled-soliton solutions can be found in the nonintegrable case. These coupled soliton solutions of CNLS correspond to "bound states" in the fiber. This boundedness is of a different character than the soliton collision described by the 2-soliton solution of a single NLS equation. Nevertheless, we show that there is remarkable agreement with the 2-soliton solution during interaction. We introduce the notion of "secondary modulation" to help the understanding of the phenomena.
LASING PROPERTIES OF A NEW TWO-PHOTON-ABSORBING MATERIAL TRANS-4-[p- (N-HYDROXYETHYL-N-ETHYLAMINO)STYRYL]- N-METHYLPYRIDINIUM p-TOLUENE SULFONATE
Authors: WANG CHUN , REN YAN , SHAO ZONGSHU , ZHAO XIAN , ZHOU GUANGYONG , WANG DONG , FANG QI , JIANG MINHUA
Published: May 2003

A new dye trans-4-[p-(N-hydroxyethyl-N-ethylamino)styryl]-N-methylpyridinium p-toluene sulfonate (HEASPS) has been synthesized. The two-photon absorption (TPA), TPA-induced frequency up-conversion emission, and two-photon pumped (TPP) frequency up-converted lasing properties of this new dye were experimentally studied. This new dye has a TPA cross-section of σ2 = 4.7 × 10-48 cm4 · s/photon at 1064 nm, but exhibits a high lasing efficiency. The net conversion efficiency from the absorbed 1064 nm pump pulse energy to the 625 nm up-converted lasing energy is 3.6% at the pump energy level of 4 mJ.
THIRD-ORDER NONLINEAR OPTICAL RESPONSE OF A NEW LINEAR POLYMER WITH 4-AMINOAZOBENZENE
Authors: KUTSENKO A. S. , MALOLETOV S. M. , BURIN O. M. , VOLKOV V. I. , BORSHCH A. A. , BRODYN M. S.
Published: May 2003

Nonlinear refraction in a new polymer material based on diglycidylether of bisphenol-A and containing 4-aminoazobenzene covalently attached to the polymer chains have been studied. The material was shown to exhibit fast nonlinear response (relaxation time about 20 ns, χ(3)= 5 × 10- 8 esu) together with slow one (relaxation time of the order of tens of hours). This makes it possible to record fast and long life (quasi stationary) phase holograms. An analysis of possible mechanisms for the refractive index nonlinear behavior in the new structure is presented. In particular, a role of electronic, thermal, orientation, and isomerization processes is discussed. It was for the first time shown that the rotational and inversion mechanisms of the cis → trans isomerization of the azo-compounds have determinative effect upon kinetics of the nonlinear refractive index relaxation. For the rotational mechanism the relaxation time was found to be 10-4 s meanwhile for the inversion mechanism it was 105 s.
SOLITONS IN MULTIPLE-CORE COUPLERS
Authors: BISWAS ANJAN
Published: May 2003

The propagation of solitons through multiple-core nonlinear fiber couplers for non-Kerr law nonlinearity is studied in this paper. The parameter dynamics of such solitons has been obtained. In particular, we have considered the ring geometry for the arrangement of fiber arrays.
CHANGE OF PARTIAL POLARIZATION OF A BEAM UNDER PHASE CONJUGATION
Authors: GOUN A. A. , ZEL'DOVICH B. YA.
Published: May 2003

Possible change of the polarization state in the process of propagation is considered theoretically. We were able to suggest a mechanism that allows for a very unusual behavior of the Stokes parameters of the beam. Specially arranged phase conjugation procedure yields the decrease of only one (e.g. ∣ζ3∣∝∣(∣Ex∣2 - ∣Ey∣2)∣) Stokes component, while the degrees of 45%- and circular polarization, ζ1 and ζ2, are not changing at all.
OPTICAL LIMITING PROPERTIES OF OPTICALLY ACTIVE METAL-FREE AND METAL PHTHALOCYANINES SUBSTITUTED WITH CHIRAL BINAPHTHYL CROWN ETHER UNITS
Authors: LIU HONGWEI , CHEN CHUANFU , XI FU , WANG PENG , ZHANG SHUANG , WU PEIJI , YE CHENG
Published: May 2003

The optical limiting properties of five optically active phthalocynines substituted with chiral binaphthyl crown ether units, (R)- and (S)- BNCE - H 2 Pc , (R)- and (S)-BNCE-CuPc, (S)-BNCE-PbPc, were investigated in solution at 532 nm with 10 ns pulses. The experimental results indicated that the (S)- and (R)-optical isomer exhibit similar optical limiting behavior and the central metal ions, Cu or Pb in the optically active metal phthalocyanine have not significantly enhanced the optical limiting behavior compared with that of the optically active metal-free phthalocyanine. In addition, the nonlinear absorption of the optically active metal-free and metal phthalocyanines was determined by the standard open aperture Z-scan technique.
ANALYSIS OF OPTICALLY INDUCED REFRACTIVE INDEX CHANGE OF DYE-DOPED NEMATIC LIQUID CRYSTALS
Authors: SHISHIDO A. , SHIH M.-Y. , KHOO I. C.
Published: May 2003

We present a detailed quantitative experimental and theoretical study of laser induced refractive index changes in nematic liquid crystals doped with methyl-red, disperse red and azobenzene liquid crystal. These refractive index changes, originating from molecular reorientations and order parameter modification, are measured by means of intensity and polarization grating methods. The reorientation of the director axis is calculated from polarization dependence of the probe beam diffraction efficiency. The contribution of each effect to the total diffraction efficiency is quantitatively evaluated. In general, we found that the reorientational direction of the NLC molecules depends on the dopants as well as the nature of the pump beam polarization state. In methyl-red doped samples, the laser induced reorientation mechanism dominates, whereas order parameter modification plays a major role in the others.
PHOTOSTABILITY STUDIES ON HIGH DIPOLE NONLINEAR OPTICAL ADDUCTS OF TCNQ IN POLYMER OPTICAL WAVEGUIDES
Authors: REN YITAO , CROSS GRAHAM H.
Published: May 2003

The photostabilities of nonlinear optical organic dyes doped as guests into Poly(methyl mathacrylate), (PMMA), waveguide films have been investigated using measurements of planner waveguide transmission over time. Direct photodecomposition of the dyes is observed when the doped films are exposed to wavelengths lying within the main absorption bands. The dyes exhibit a rapid photochemical degradation that is enhanced when the experiments are repeated in an air environment at the irradiation between 450 nm and 515 nm. Excitation of the zeroth-order transverse magnetic mode (TM0) by prism couplers produced complete degradation within 30 minutes. The dye photostabilities are compared to that of a commonly studied laser dye, 4-dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran, DCM, which exhibits a photo-oxidation mechanism. The experiments in air lead to comparable degradation after 3 to 4 hours but the dye proves to be exceptionally photostable in vacuum. Further interesting results are reported on the formation of crystallites in the films when irradiated at 632.8 nm where linear absorption in the films is low. Microscopic examination of the waveguide films at the input coupling position confirms the formation of crystallites for all the films studied. Cross coupling to higher order modes from the light scattering of crystallites is revealed by scanning m-line images of the waveguides. This is associated with a marked refractive index decrease in the films. An air and humidity environment is found to favor the crystallite formation in the dye-doped waveguides.
PHYSIOLOGICAL CONSIDERATIONS IN FUNCTIONAL 3-D LUMBAR DIAGNOSIS: NON-PHYSIOLOGICAL TESTS
Authors: Steinberg E. L. , Nissan M. , Bar-Ilan K. , Menahem A. , Arbel R. , Luger E.
Published: May 2003

Lumbar spine function may be clinically assessed by subjective physician findings or by a more sophisticated mean such as 3-D dynamometric system. This system was developed to differentiate objectively between physiologic and non-physiological behavior of LBP patients. The same system is used, concurrently, to categorize the physiologic tests according to functional limitation. The four major parameters used for assessing spinal disability are: range of motion, maximal isometric torque, maximal velocity and maximal torque in the secondary axis. Six other independent parameters were used in order to assess non-cooperative or non-physiologic behavior. For the study, 108 non-symptomatic subjects and 595 LBP patients were tested. All patients had a physical examination before being tested on the dynamometric device (the IsoStation B-200). One hundred and ten patients were classified as non-physiological and 91 were classified in the gray zone.

The results support the use of 3-D dynamometry to objectively classify the patient's performance reliability. The measured parameters are objective and reliable indicators of the patient's physical condition and credibility that should influence both the patient's assessment and treatment.
DEVELOPMENT OF A SEATED DEVICE FOR MEASURING DIURNAL VARIABILITY IN SPINAL COMPRESSION
Authors: Haiduven Donna , Baptiste Andrea , Luther Stephen , Lloyd John D. , Wilkinson Stuart , Bidot Pascual
Published: May 2003

Research on external spinal compression has consisted mainly of laboratory-based evaluations of specific exercise interventions on spinal compression in athletes and industrial employees. The purpose of this pilot study was to test the reliability of a seated stadiometry device for measuring external spinal compression in a sample of nurses and non-nurses. This research will be used to study nurses in future studies. Twenty-three subjects were marked externally at the C7 spinal process. Two investigators collected measures of seated spinal length. Six measurements were taken within a five-minute period on the morning of day one, repeated four hours later, and one week later. Comparisons were made using ANOVA between (1) three sets of repeated measures; (2) inhalation and exhalation; (3) morning and afternoon sessions; and (4) weeks one to two. A statistically significant differece was found in mean measures of displacement (-2.29 mm to -4.07 mm) between morning and afternoon but not between inhalation and exhalation or in successive weeks. Inter-rater reliability between two investigators was excellent. The stadiometer proved highly reliable. It will be used to investigate the relationship between spinal compression and back pain in nurses in the workplace.
GROWTH AFTER RUBBING BY TUMOR CUT SURFACE: COMPARATIVE STUDY BETWEEN THREADWIRE SAW-CUT AND BLUNTLY-CUT TUMORS
Authors: Abdel-Wanis Mohamed El-Sayed , Tsuchiya Hiroyuki , Kawahara Norio , Tomita Katsuro
Published: May 2003

Spondylectomy for extripation of spinal tumors would be performed through piecemeal excision or by total en bloc spondylectomy with cutting at the neural arch by the threadwire saw (T-saw) that is sometimes inevitably intralesional. The purpose of this study was to compare the potential for tumor growth after rubbing of the cut surface of tumors cut by either T-saw or blunt instrument against the subcutaneous tissues of nude mice. Tumors were prepared by subcutaneous injection of human HT 1080 fibrosarcoma cells in nude mice. The animals were sacrificed, and tumors were harvested en bloc and cut with either a T-saw or artery forceps. A 3-cm wound was created on the backs of other (plain) nude mice. The tumor's cut surface was rubbed for 10 seconds against the subcutaneous tissue of one of these nude mice. The wounds were then sutured. Tumor blocks were inoculated into other nude mice. Nude mice were followed for occurrence of tumor growth. Tumor growth occurred in all nude mice after block inoculation. The incidence of tumor growth after rubbing with the tumor surfaces cut with T-saw and artery forceps were 16.7% and 58.3% respectively (P = 0.035). Onset of tumor growth after tumor rubbing and inoculation of tumor blocks were 30.1 ± 25 and 12.2 ± 5 days respectively (P = 0.015). Rubbing of T-saw-cut tumor surface has less possibility of causing tumor growth than rubbing of surface of bluntly-cut tumors.
VALIDATION OF MRI-BASED MEASUREMENTS OF SUPRASPINATUS MORPHOLOGY
Authors: Nakajima Tomotaka , Hughes Richard E. , An Kai-Nan
Published: May 2003

The goal of this study was to visualize the supraspinatus tendon three-dimensionally using fast spin-echo (FSE) MRI and validate the accuracy of measuring the dimensions of the supraspinatus tendon based on 3D reconstructed images. Nine cadaver shoulders (51–84 y/o, mean 70.0 y/o) were imaged at conventional T2-weighted spin-echo (CSE), gradient echo (GRE), and 3D T2-weighted FSE sequences. Each "object" of the supraspinatus muscle, tendon and scapula was three-dimensionally reconstructed using ANALYZE™ image data processing software. The FSE images revealed significantly higher contrast of the tendon and contrast-to-noise ratios of the fat-to-tendon and fat-to-muscle. The length of the anterior, middle, and posterior portions of the tendon were measured in two ways: (1) from the three-dimensional reconstructed images, and (2) directly from the cadaver specimen using calipers. No statistically significant differences were found between the ANALYZE™ and caliper measurements using a paired t-test for the anterior (p = 0.55), middle (p = 0.57) and posterior (p = 0.44) portions of the supraspinatus. The 3D FSE sequence exhibits higher spatial resolution, spends shorter acquisition time, and constructs a voxel data set. These advantages can prevent blurring artifacts when imaging the supraspinatus tendon of a human body. Tendon length measurements derived from three-dimensional reconstructions using ANALYZE™ were found to be good estimates of actual tendon length. Therefore, the combination of FSE sequence and 3D image data processing provides a method for noninvasive quantitative analysis of supraspinatus tendon morphology. The results lay the groundwork for future quantitative studies of cuff pathology.
CLINICAL PREDICTORS FOR OUTCOME OF TREATMENT OF LUMBAR HERNIATED NUCLEUS PALPOSUS
Authors: Buranapanitkit B. , Tautakul K. , Lim A. , Geater A. , Chomchan U.
Published: May 2003

Herniated nucleus palposus is a common and important cause of low back pain. Despite over 90% of the patients responding to conservative treatment, some patients still need operation. This study aimed to analyze the clinical predictors for the outcome of conservative treatment in herniated nucleus palposus. Two hundred and fifty-one patients who were diagnosed as lumbar herniated nucleus palposus and admitted to Prince of Songkla University during the period of 1995–2000 were included in the study. Patients who had absolute indications for surgery or had previous back surgery were excluded. Data were collected on demographic characteristics (age, sex, occupation, level of study, marital status), patient symptoms (including duration, characteristic and severity of pain) and result of physical examination (including result of straight leg raising test (SLRT), cross SLRT, motor power, sensory deficit and reflex). The mean age of the patients was 38 years and the mean duration of pain was 4.1 months. Eighty percent of the patients had positive SLRT and abnormal neurological function was found in 73%. One hundred and eighty-six patients underwent surgery owing to failure of conservative treatment. From multivariate logistic analysis, five independent factors affecting failure of conservative treatment of herniated nucleus palposus were pain intensity, duration of symptoms, positive cross SLRT, grade of muscle power and number of dermatome deficit. When constructing the parameters into a scoring system, we found that if the patient had a score less than 45, 80% of them respond to conservative treatment, in contrast to those who scored more than 65, the probability of conservative failure was 80%. This study implies that clinical predictors can be used for determining probability of conservative failure in herniated nucleus palposus.
INGROWTH OF NEURAL ELEMENTS INTO THE ANNULUS FIBROSUS OF OVINE INTERVERTEBRAL DISC IN AN ACUTE AND SUBACUTE EXPERIMENTAL DISC INJURY
Authors: Lappalainen A. K. , Kääpä E. , Grönblad M.
Published: May 2003

Ingrowth of nerves and blood vessels is regarded as a part of disc degeneration. Schwann cells, which guide the development and regeneration of nerves both in the central and peripheral nervous system, have recently been located in degenerated human discs.

The purpose of this study was to investigate by immunohistochemical methods, whether or not there was nerve, Schwann cell and blood vessel ingrowth in experimentally induced acute (3 weeks) and subacute (3 months) annular tears; and to study the detailed topography of such nerve ingrowth when present. Ingrowth of nerves and Schwann cells has so far not been studied in experimentally induced acute annular tears.

A stab incision with a scalpel blade was made in two adjacent lumbar discs in adult sheep (n = 9). The L2–L3 discs were injured superficially, whereas in L3–L4 discs the incision reached the nucleus pulposus (full-thickness injury). The animals were sacrificed three weeks (acute injury, n = 3) or three months (subacute injury, n = 6) post-operatively. Discs were immunoassayed for general neuronal markers (protein gene product 9.5, PGP 9.5 and synaptophysin, SYN), Schwann cell marker (glial fibrillary acidic protein, GFAP) and endothelial marker (CD 31).

Nerves visualized with all antibodies employed were situated inside the injured area and mainly near amd around blood vessels although free nerve endings could be seen also. PGP 9.5-immunopositive nerves were evident in every sample. Immunoreactivity to SYN and GFAP was not observed in control discs. Such immunoreactivity appeared already at 3 weeks (acute injury) in a few samples, and was present in all samples at 3 months (subacute injury). For the superficial injury, nerves did not penetrate deeper than in control discs until at 3 months. With more extensive annular injury, mean values for both nerve and Schwann cell penetration were higher. Blood capillaries were visible deeper in the inner annulus than neural tissues immunopositive to PGP 9.5, GFAP or SYN.

The results suggest an ingrowth of nerves and Schwann cells with time, following an injury of the annulus fibrosus. A trend for deeper penetration already in the acute stage, but only for deep lesions reaching all the way to the nucleus pulposus, may be suggested. Such ingrowth, also previously reported in degenerated human discs, may relate to mechanisms of low back pain, originating in the intervertebral disc.
PYOGENIC SACROILIITIS REPORT OF 11 CASES AND REVIEW OF LITERATURE
Authors: Chao E. K. , Chen L. H. , Ueng S. W. N. , Yeh W. L. , Chen W. J. , Chang Y. H. , Lee M. S.
Published: May 2003

The general principle of treatment of pyogenic sacroiliitis is antibiotic therapy over a six-week duration with or without surgery. Surgery is believed to be reserved for drainage of local abscess, obtaining specimens for pathologic diagnosis, and for cases with poor medical responses. From 1987 to 1999, there were 11 cases (6 women and 5 men) with confirmed diagnosis of pyogenic sacroiliitis treated at the authors' institute. The average age was 42 years. The onset of disease was acute in 8, subacute in 2, and chronic in 1 case. The most common causative pathogen was staphylococcus aureus. Among the 11 cases, only 2 cases were treated by surgery and the remaining 9 cases were treated medically. All the 11 patients recovered well without major complication. To re-examine whether an abscess formation warrants surgical drainage, 193 cases collected from the literature were analyzed with specific attention to the reported surgical indication. The results indicated that an abscess need not be drained surgically and the surgically treated patients were neither more toxic nor with more favorable outcomes than the medically treated patients. In conclusion, the authors suggest that pyogenic sacroiliitis can primarily be treated conservatively with antibiotics and image-guided drainage. It is thought that surgery should be reserved for cases with poor medical response or for advanced sacroiliac destruction.
SHOULDER MUSCULOSKELETAL DISORDERS IN INDUSTRIAL AND OFFICE WORK
Authors: Fagarasanu Mircea , Kumar Shrawan
Published: May 2003

Although several studies addressed the work-related shoulder pathology, there is still a lack of knowledge regarding the causal relationship between different factors in industrial/office activities and shoulder musculoskeletal disorders. The goal of this review is to evaluate in a realistic manner the role of the factors implicated in the shoulder disorders development in high-risk activities. This article reviews the actual state of information regarding the etiological relationship between physical and psychosocial stress and occupational musculoskeletal problems in shoulder area, emphasizing the relationship between ergonomic interventions on musculoskeletal system. Secondly, a comprehensive presentation of the pathophysiology and etiology of shoulder muscle problems is provided. Critical factors such as arm elevation, lack of rest, overloading of several muscles and mental stress during performed tasks are discussed in relation to shoulder musculoskeletal disorders development. Finally, using the available data, the authors present a thorough recommendation of mandatory redesign interventions with suggestions for future research in this area.
HOW TO GENERATE MARKOVIAN COCYCLES ON BOSON FOCK SPACE
Authors: LIEBSCHER VOLKMAR
Published: May 2003

We show a simple way to generate a Markovian cocycle on H ⊗ Γ (L2(ℝ+, K)) from a semigroup of bounded operators on (H ⊗ L2(ℝ+, K)) ⊕ H ⊕ (H ⊗ L2(ℝ-, K) ⊗ L2(ℝ+, K))⊕ (H ⊗ L2(ℝ-, K)).
PROJECTIVE SPACE OF A C*-MODULE
Authors: ANDRUCHOW ESTEBAN , CORACH GUSTAVO , STOJANOFF DEMETRIO
Published: May 2003

Let X be a right Hilbert C*-module over A. We study the geometry and the topology of the projective space [Formula: see text] of X, consisting of the orthocomplemented submodules of X which are generated by a single element. We also study the geometry of the p-sphere Sp(X) and the natural fibration [Formula: see text], where Sp(X) = {x ∈ X:  = p}, for p ∈ A a projection. The projective space and the p-sphere are shown to be homogeneous differentiable spaces of the unitary group of the algebra ℒA(X) of adjointable operators of X. The homotopy theory of these spaces is examined.
UNITS FOR THE TIME-ORDERED FOCK MODULE
Authors: LIEBSCHER VOLKMAR , SKEIDE MICHAEL
Published: May 2003

We give an explicit formula for all continuous units for the product system associated with an arbitrary time-ordered Fock module over a two-sided Hilbert ℬ-module. Like in the case of the symmetric Fock space, the units may be considered as exponential vectors to indicator function possibly renormalized by a semigroup. However, since this semigroup takes values in ℬ, the renormalization must be done more carefully. It turns out that the generators of the CP-semigroups on ℬ associated with our units are precisely the Christensen–Evans generators. Finally, we present an example which shows that the situation changes considerably, when we drop the continuity condition.
A CHARACTERISATION OF WIGNER–YANASE SKEW INFORMATION AMONG STATISTICALLY MONOTONE METRICS
Authors: GIBILISCO PAOLO , ISOLA TOMMASO
Published: May 2003

Let [Formula: see text] be the space of n × n complex matrices endowed with the Hilbert–Schmidt scalar product, let Sn be the unit sphere of Mn and let Dn⊂ Mn be the space of strictly positive density matrices. We show that the scalar product over Dn introduced by Gibilisco and Isola3 (that is the scalar product induced by the map [Formula: see text]) coincides with the Wigner–Yanase monotone metric.
ADAPTIVE FAULT-TOLERANT ROUTING IN STAR NETWORKS
Authors: DAY KHALED , AL-AYYOUB ABDEL-ELAH
Published: May 2003

We take advantage of the hierarchical structure of the star graph network to obtain an efficient method for constructing node-disjoint paths between arbitrary pairs of nodes in the network. A distributed fault-tolerant routing algorithm for the star network based on this construction method is then presented and evaluated. The proposed algorithm adapts the routing decisions in response to node failures. Node failure and repair conditions may arise dynamically (at any time) provided that the total number of faulty nodes at any given time is less than the node-connectivity n - 1 of the n-star. When a message is blocked due to faulty components, the source of the message is warned and requested to switch to a different node-disjoint path. The methods used to identify the paths, to propagate failure information back to source nodes, and to switch from a routing path to another incur little communication and computation overhead. We show that if the node failures occur 'reasonably' apart in time, then all messages will be routed on paths of length δ + ε where δ is the minimum distance between the source and the destination and ε is 0, 2, or 4. In the unlikely case where more failures occur in a 'short period', the algorithm still delivers all messages but via possibly longer paths.
JDM: BUILDING DISTRIBUTED SYNCHRONIZATION SUPPORT INTO JAVA
Authors: CAO JIANNONG , CHEUNG NICK K. C. , CHAN ALVIN
Published: May 2003

The monitor concept has been widely used in a concurrent programming environment for implicitly ensuring mutual exclusion and explicitly achieving process synchronization. It has also been extended to support high-level distributed programming. In this paper, we present JDM, a distributed monitor construct in Java for programming large-scale distributed systems. The distributed monitor construct is based on a well-know tree-based distributed mutual exclusion algorithm proposed by K. Raymond. To increase scalability of the construct, a two-level system architecture is developed, where the node level controls the access to the system-wide shared resources using Raymond's algorithm and the process level synchronizes local processes based on the local monitor concept. An object-oriented design of the system architecture is presented. Implementation and results of performance evaluation are reported and factors that influence the performance of the construct are discussed.
AUTOMATIC PARALLELISATION AND EXECUTION OF APPLICATIONS ON CLUSTERS
Authors: MCAVANEY CHRISTOPHER , GOSCINSKI ANDRZEJ
Published: May 2003

Parallel execution is a very efficient means of processing vast amounts of data in a small amount of time. Creating parallel applications has never been easy, and requires much knowledge of the task and the execution environment used to execute parallel processes. The process of creating parallel applications can be made easier through using a compiler that automatically parallelises a supplied application. Executing the parallel application is also simplified when a well designed execution environment is used. Such an execution environment provides very powerful operations to the programmer transparently. Combining both a parallelising compiler and execution environment and providing a fully automated parallelisation and execution tool is the aim of this research. The advantage of using such a fully automated tool is that the user does not need to provide any additional input to gain the benefits of parallel execution. This report shows the tool and how it transparently supports the programmer creating parallel applications and supports their execution.
TRIPWIRE: A SYNCHRONISATION PRIMITIVE FOR VIRTUAL MEMORY MAPPED COMMUNICATION
Authors: RIDDOCH DAVID , POPE STEVE , ROBERTS DEREK , MAPP GLENFORD , CLARKE DAVID , INGRAM DAVID , MANSLEY KIERAN , HOPPER ANDY
Published: May 2003

Existing user-level network interfaces deliver high bandwidth, low latency performance to applications, but are typically unable to support diverse styles of communication and are unsuitable for use in multiprogrammed environments. Often this is because the network abstraction is presented at too high a level, and support for synchronisation is inflexible.

In this paper we present a new primitive for in-band synchronisation: the Tripwire. Tripwires provide a flexible, efficient and scalable means for synchronisation that is orthogonal to data transfer. We describe the implementation of a non-coherent distributed shared memory network interface, with Tripwires for synchronisation. This interface provides a low-level communications model with gigabit class bandwidth and very low overhead and latency. We show how it supports a variety of communication styles, including remote procedure call, message passing and streaming.
BUCKLING ANALYSIS OF CONCRETE-FILLED FRP TUBES
Authors: YUAN WENQING , MIRMIRAN AMIR
Published: May 2003

Fiber reinforced polymer (FRP) tubes can be filled with concrete to serve as structural columns or piles. The tube provides confinement and strength for the core, whereas the concrete core enhances the overall stability of the system. This paper reports on an analytical and experimental study of the static buckling of thin-walled FRP tubes filled with concrete and bent in single curvature. A comprehensive parametric study on over 11 500 columns shows that concrete-filled FRP tubes are much more susceptible to buckling than concrete columns with internal steel reinforcement. A number of modifications are suggested for the existing stability design equations of critical length and moment magnification of concrete columns to make them applicable to concrete-filled FRP tubes.
VIDEO CONTENT REPRESENTATION FOR SHOT RETRIEVAL AND SCENE EXTRACTION
Authors: LIN TONG , ZHANG HONG-JIANG , SHI QING-YUN
Published: May 2003

In this paper, we present a novel scheme on video content representation by exploring the spatio-temporal information. A pseudo-object-based shot representation containing more semantics is proposed to measure shot similarity and force competition approach is proposed to group shots into scene based on content coherences between shots. Two content descriptors, color objects: Dominant Color Histograms (DCH) and Spatial Structure Histograms (SSH), are introduced. To represent temporal content variations, a shot can be segmented into several subshots that are of coherent content, and shot similarity measure is formulated as subshot similarity measure that serves to shot retrieval. With this shot representation, scene structure can be extracted by analyzing the splitting and merging force competitions at each shot boundary. Experimental results on real-world sports video prove that our proposed approach for video shot retrievals achieve the best performance on the average recall (AR) and average normalized modified retrieval rank (ANMRR), and Experiment on MPEG-7 test videos achieves promising results by the proposed scene extraction algorithm.
DECISION MAKING, HABITUAL DOMAINS AND INFORMATION TECHNOLOGY
Authors: YU P. L. , CHIANG C. I.
Published: May 2003

In this paper, we discuss how information technology (IT) affects and influences people to make decisions. We first introduce human behavior mechanism and habitual domains — the software that drive the behaviors. Then we discuss the impacts of IT on decision elements and environment, and then IT's impacts on a variety of decision problems including routine problems, mixed routine problems, fuzzy problems and challenging problems. IT is useful in solving routine problems but not as obvious in solving fuzzy and challenging problems. To solve fuzzy and challenging problems, an effective concept and model of competence set analysis is introduced. Finally, we describe three types of competence set analysis and show how IT can help in these three types of problems.
AN EFFECTIVE ALGORITHM FOR COMPUTING EQUILIBRIUM OUTCOME OF A CLASS OF SIGNALING GAMES
Authors: YU GANG , SHENG ZHAOHAN , XIAO TIAOJUN
Published: May 2003

In this paper, we study the class of signaling games in which a unique perfect Bayesian Nash equilibrium outcome satisfying the Intuitive Criterion exists. We first describe the models of signaling games and lay out the definition of equilibrium and some basic assumptions. We then prove three basic theorems leading to the proof of the main theorem that gives sufficient conditions under which a signaling game has a unique outcome. The proof of the main theorem also leads to a method for computing the equilibrium outcome. We formally present the algorithm and illustrate its application through a numerical example. Finally, we apply our algorithm to enterprise management decision-making.
DYNAMIC MCDM: THE CASE OF URBAN INFRASTRUCTURE DECISION MAKING
Authors: VO HUY V. , CHAE BONGSUG , OLSON DAVID L.
Published: May 2003

Many societal decisions involve complexity and conflicting objectives. Preferences in such environments can be expected to change as situations evolve. In this paper, we propose a procedure that incorporates Multiple Criteria Decision Making (MCDM) into system dynamics modeling to handle dynamic multiple criteria situations, which we name dynamic MCDM. A case of urban infrastructure is presented to illustrate the procedure. Dynamic MCDM can handle different lags in economic, social, economic and technical effects of large scale systems. Thus, it may help decision makers avoid selecting alternatives apparently effective in the short term, but detrimental in the long term.
REALIZING FACE-TO-FACE INTERACTION BY VIEW-BASED TRACKING
Authors: LI SHIGANG , REN FUJI
Published: May 2003

In this paper, we propose a method of realizing face-to-face interaction by view-based tracking between a human and a mobile robot. Although individuals can be recognized easily by observing frontal faces, it is difficult to do it from profiles of face. To cope with this problem, our mobile robot first finds face-like areas based upon the skin color distribution which is made from real image samples. Second, a facial pattern in the image is found and its direction relative to the robot is estimated in terms of the memorized views. Finally, the mobile robot moves to the front of the face according to the face direction while tracking the face by using visual feedback based upon active vision approach.
User-interface design and China
Authors: Marcus Aaron
Published: May 2003

If user-interface design seeks to encompass human-experience design, then computer-based communication and interaction designers need to keep Asian, specifically Chinese, users in mind. China, with approximately one-fifth of the world's population, an economy that is growing quickly, and a manufacturing system that exports a significant percentage of the goods imported into the world's countries, needs to be considered in revising concepts of user-interface and user-experience design.
Literature-based discovery on the World Wide Web
Authors: Gordon Michael , Lindsay Robert K. , Fan Weiguo
Published: May 2003

Previous research has shown that researchers can generate medical hypotheses by using computers to analyze several, seemingly unrelated, medical literatures. In this work we suggest broader application for the ideas of literature-based discovery. Specifically, we suggest that literature-based discovery can be fruitful in areas other than medicine; that in addition to finding "cures" for "problems," literature-based discovery offers the possibility of finding new problems for existing technologies; that the analysis of a single literature may be sufficient for literature-based discovery; and that literature-based discovery can support individuals seeking to draw together ideas from various areas of inquiry, even if such connections have been previously made by others.We describe literature-based discovery experiments conducted on the World Wide Web that support these ideas.
The platform for privacy preference as a social protocol
Authors: Hochheiser Harry
Published: May 2003

As a "social protocol" aimed at providing a technological means to address concerns over Internet privacy, the Platform for Privacy Preferences (P3P) has been controversial since its announcement in 1997. In the U.S., critics have decried P3P as an industry attempt to avoid meaningful privacy legislation, while developers have portrayed the proposal as a tool for helping users make informed decisions about the impact of their Web surfing choices. This dispute touches upon the privacy model underlying P3P, the U.S. political context regarding privacy, and the technical components of the protocol. This article presents an examination of these factors, with an eye towards distilling lessons for developers of future social protocols.
Affinity-based management of main memory database clusters
Authors: Ji Minwen
Published: May 2003

We study management strategies for main memory database clusters that are interposed between Internet applications and back-end databases as content caches. The task of management is to allocate data across individual cache databases and to route queries to the appropriate databases for execution. The goal is to maximize effective cache capacity and to minimize synchronization cost. We propose an affinity-based management system for main memory database cLUsters (
ALBUM
). ALBUM executes each query in two stages in order to take advantage of the
query affinity
that is observed in a wide range of applications. We evaluate the data/query distribution strategy in ALBUM with a set of trace-based simulations. The results show that ALBUM reduces cache miss ratio by a factor of 1.7 to 9 over alternative strategies. We have implemented a prototype of ALBUM, and compare its performance to that of an existing infrastructure: a fully replicated database with large buffer cache. The results show that ALBUM outperforms the existing infrastructure with the same number of server machines by a factor of 2 to 7, and that ALBUM with only 1/3 to 1/2 of the server machines achieves the same throughput as the existing infrastructure.
Supporting structured credentials and sensitive policies through interoperable strategies for automated trust negotiation
Authors: Yu Ting , Winslett Marianne , Seamons Kent E.
Published: May 2003

Business and military partners, companies and their customers, and other closely cooperating parties may have a compelling need to conduct sensitive interactions on line, such as accessing each other's local services and other local resources. Automated trust negotiation is an approach to establishing trust between parties so that such interactions can take place, through the use of access control policies that specify what combinations of digital credentials a stranger must disclose to gain access to a local resource. A party can use many different strategies to negotiate trust, offering tradeoffs between the length of the negotiation, the amount of extraneous information disclosed, and the computational effort expended. To preserve parties' autonomy, each party should ideally be able to choose its negotiation strategy independently, while still being guaranteed that negotiations will succeed whenever possible---that the two parties' strategies will interoperate. In this paper we provide the formal underpinnings for that goal, by formalizing the concepts of negotiation protocols, strategies, and interoperation. We show how to model the information flow of a negotiation for use in analyzing strategy interoperation. We also present two large sets of strategies whose members all interoperate with one another, and show that these sets contain many practical strategies. We develop the theory for black-box propositional credentials as well as credentials with internal structure, and for access control policies whose contents are (respectively are not) sensitive. We also discuss how these results fit into TrustBuilder, our prototype system for trust negotiation.
On the relationship between strand spaces and multi-agent systems
Authors: Halpern Joseph Y. , Pucella Riccardo
Published: May 2003

Strand spacesare a popular framework for the analysis of security protocols. Strand spaces have some similarities to a formalism used successfully to model protocols for distributed systems, namelymulti-agent systems. We explore the exact relationship between these two frameworks here. It turns out that a key difference is the handling of agents, which are unspecified in strand spaces and explicit in multi-agent systems. We provide a family of translations from strand spaces to multi-agent systems parameterized by the choice of agents in the strand space. We also show that not every multi-agent system of interest can be expressed as a strand space. This reveals a lack of expressiveness in the strand-space framework that can be characterized by our translation. To highlight this lack of expressiveness, we show one simple way in which strand spaces can be extended to model more systems.
Delegation logic
Authors: Li Ninghui , Grosof Benjamin N. , Feigenbaum Joan
Published: May 2003

We address the problem of authorization in large-scale, open, distributed systems. Authorization decisions are needed in electronic commerce, mobile-code execution, remote resource sharing, privacy protection, and many other applications. We adopt the trust-management approach, in which "authorization" is viewed as a "
proof-of-compliance
" problem: Does a set of credentials prove that a request complies with a policy?We develop a logic-based language, called
Delegation Logic
(DL), to represent policies, credentials, and requests in distributed authorization. In this paper, we describe D1LP, the monotonic version of DL. D1LP extends the logic-programming (LP) language Datalog with expressive delegation constructs that feature delegation depth and a wide variety of complex principals (including, but not limited to, k-out-of-n thresholds). Our approach to defining and implementing D1LP is based on tractably compiling D1LP programs into ordinary logic programs (OLPs). This compilation approach enables D1LP to be implemented modularly on top of existing technologies for OLP, for example, Prolog.As a trust-management language, D1LP provides a concept of proof-of-compliance that is founded on well-understood principles of logic programming and knowledge representation. D1LP also provides a logical framework for studying delegation.
BDD-based logic synthesis for LUT-based FPGAs
Authors: Vemuri Navin , Kalla Priyank , Tessier Russell
Published: May 2003

Contemporary FPGA synthesis is a multiphase process that involves technology-independent logic optimization followed by FPGA-specific mapping to a target FPGA technology. Conventional technology-independent transformations target standard cells and are unable to optimize circuits with constraints and goals specific to FPGA architectures. This article describes an
FPGA-specific
logic synthesis approach, which unites multilevel logic transformation, decomposition, and optimization techniques into a single synthesis framework. This system performs network transformation, decomposition, and optimization at an early stage to generate a network that can be
directly
mapped onto FPGAs. Our techniques are built upon a BDD-based logic decomposition system. With this system, both AND-OR decompositions
and
AND-XOR decompositions can be identified, resulting in large area savings for synthesized XOR-intensive circuits. To induce good decompositions, a
maximum fanout free cone
(MFFC) -based partial clustering and collapsing technique is used. This step is followed by an area-minimizing variable partitioning heuristic that decomposes collapsed nodes into LUT-feasible subfunctions. As a postprocessing step, a performance-driven resynthesis phase is performed to alleviate increased delay caused by excessive logic sharing. We compare the quality of results obtained using our techniques with those of academic (BoolMap, SIS) and industry (Altera Quartus) FPGA synthesis tools. Experimental results indicate that the circuits generated by our techniques are not only smaller, but are also significantly faster than those synthesized by conventional FPGA synthesis tools. Furthermore, the computation times required by our techniques are significantly smaller than those of previous techniques.
Reduction design for generic universal switch blocks
Authors: Fan Hongbing , Liu Jiping , Wu Yu-Liang , Wong C. K.
Published: May 2003

A
k
-side switch block with
W
terminals per side is said to be a universal switch block ((
k
,
W
)-USB) if every set of the nets satisfying the routing constraint (i.e., the number of nets on each side is at most
W
) is simultaneously routable through the switch block. The (4,
W
)-USB was originated by designing better switch modules for 2-D FPGAs, such as Xilinx XC4000-type FPGAs, whereas the generic USBs can be applied in multidimensional or some nonconventional 2-D FPGA architectures. The problem we study in this article is to design (
k
,
W
)-USBs with the minimum number of switches for any given pair of (
k
,
W
). We provide graph models for routing requirements and switch blocks and develop a series of decomposition theorems for routing requirements with the help of a new graph model. The powerful decomposition theory leads to the automatic generation of routing requirements and a detailed routing algorithm, as well as the reduction design method of building large USBs by smaller ones. As a result, we derive a class of well-structured and highly scalable optimum (
k
,
W
)-USBs for
k
≤ 6, or even
W
s, and near-optimum (
k
,
W
)-USBs for
k
≥ 7 and odd
W
s. We also give routing experiments to justify the routing improvement upon the entire chip using the USBs. The results demonstrate the usefulness of USBs.
Run-time performance optimization of an FPGA-based deduction engine for SAT solvers
Authors: Dandalis Andreas , Prasanna Viktor K.
Published: May 2003

FPGAs are a promising technology for accelerating SAT solvers. Besides their high density, fine granularity, and massive parallelism, FPGAs provide the opportunity for run-time customization of the hardware based on the given SAT instance. In this article, a parallel deduction engine is proposed for backtrack search algorithms. The performance of the deduction engine is critical to the overall performance of the algorithm because, for any moderate SAT instance, millions of implications are derived. We propose a novel approach in which
p
, the amount of parallelization of the engine, is fine-tuned during problem solving in order to optimize performance. Not only the hardware is initially customized based on the input instance, but it is also dynamically modified in terms of
p
based on the knowledge gained during solving the SAT instance. Compared with conventional deduction engines that correspond to
p
= 1, we demonstrate speedups in the range of 2.87 to 5.44 for several SAT instances.