Simultaneous Joint Research Articles

Joint inversion of marine magnetotelluric and gravity data incorporating seismic constraints: Preliminary results of sub-basalt imaging off the Faroe Shelf

Breakup of the North Atlantic during the early tertiary was accompanied by widespread and massive magmatism, resulting in the coverage of large areas of the North Atlantic with flood basalts. These flood basalts hamper seismic investigations of underlying sequences and thus the understanding of the rifting, subsidence and evolution of the margin which, in turn, increases the risk for hydrocarbon exploration. In this paper we present a methodology for the simultaneous joint inversion of diverse geophysical datasets, i.e. free air gravity and magnetotelluric soundings (MT) using seismic a priori constraints. The attraction of the joint inversion approach is that different geophysical measurements are sensitive to different properties of the sub-surface, so through joint inversion we significantly reduce the null space and produce a single model that fits all datasets within a predefined tolerance. Using sensitivity analysis of synthetic data, we show how each data set contains complementary important information of the supra and sub-basalt structure. While separate inversions of individual datasets fail to image through the basalt layer, our joint inversion approach leads to a much improved sub-basalt structure. Application of the joint inversion algorithm to satellite gravity data and MT data acquired on the FLARE10 seismic line south west of Faroe islands supports the existence of a 1 km to 2 km thick low velocity region that might be indicative of the existence of a sedimentary basin underneath the basalt layer. Though in this paper we demonstrate the use of joint inversion on a sub-basalt target, we believe it has wider applicability to other areas where conventional seismic imaging fails.

Calibration of Mechanistic–Empirical Pavement Design Guide Permanent Deformation Models

The performance models in the Mechanistic–Empirical Pavement Design Guide (MEPDG), developed under NCHRP 1-37A and 1-40D, are calibrated with sections throughout the United States. Hence, it is necessary to calibrate these models for specific states and regional conditions because of the differences in materials, environmental conditions, and construction practices. In general, a pavement design based on the nationally calibrated MEPDG will result in either an overestimate or underestimate of the pavement layer thicknesses because of systematic errors arising from local differences. This deficiency calls for local calibration of the performance models in the MEPDG so that they can be used to design pavements at a regional level. The calibration procedure described in this paper concentrates on finding two bias correction factors for the asphalt concrete (AC) permanent deformation performance model after values derived from expert knowledge have been assumed for the subgrade permanent deformation calibration factors. Pavement data from the Texas Specific Pavement Study (SPS)-1 and SPS-3 experiments of the Long-Term Pavement Performance database were used to run the MEPDG and calibrate the guide to Texas conditions. The regional calibration factors were obtained by minimizing the sum of squared errors between the observed and predicted surface permanent deformation. In this case, a simultaneous joint optimization routine was applied because it was theoretically sound. Finally, an average of the regional calibration coefficients for AC and subgrade permanent deformation was computed to obtain the set of state-default calibration coefficients for Texas.

Simultaneous Joint Control of a Hydraulic Manipulator for Joystick and VR Interface

Simultaneous Joint Control of a Hydraulic Manipulator for Joystick and VR Interface

Near-surface P-velocity modelling by integrated seismic, EM, and gravity data: examples from the Middle East

Onshore seismic data from the Middle East and around the world are adversely affected by near-surface velocity anomalies. Shallow-section velocity characterization represents a key issue for land data processing in both time and depth domains. In the Middle East, near-surface complexity can be attributed to sand dunes, wadies, sabkha environment, shallow high-velocity layers (carbonate outcrops), karsting, and fractured layers. The correct estimate of the near-surface velocity field is fundamental to obtain reliable seismic images. Conventional workflows for near-surface model building often involve interpreting and inverting refracted arrival information. These methods may fail to appropriately reconstruct the shallow velocity complexities in the presence of large velocity inversions, rapid lateral velocity changes, and noisy refracted arrival data. The combination of additional geophysical measurements (i.e., non-seismic), not influenced by the problems affecting seismic propagation, are needed to address the shallow velocity modelling problem. This paper describes three different approaches recently applied in distinctly different environments around the Middle East to solve near-surface modelling problems. The first example from the United Arab Emirates (UAE) demonstrates the integration of seismic and time-domain electromagnetics (TDEM) for sand dune statics application. The second example from Saudi Arabia also addresses sand dune statics, but this time by simultaneous joint inversion (JI) of seismic and gravity measurements. The final example applies the simultaneous JI technique for the near-surface velocity component of a depth migration model.

Simultaneous Joint Arthrodesis and Bone Lengthening by the Ilizarov Method (A Case Report)

Large osteoarticular defects of the extremities are challenge cases in orthopaedic surgery. Although there are several conventional treatment options for this kind of skeletal defects, the rate of success is low. We report the case of a 48-year-old patient in whom a large osteoarticular defect including the whole distal tibia, distal fibula and talar dome of the right leg, due to a gunshot injury, was treated with tibial lengthening and tibiotalar fusion by the Ilizarov method. Selected treatment was not just a simultaneous arthrodesis and limb lengthening procedure. Whole distal tibia and ankle region was simultaneously reconstructed using tibiotalar fusion and proximal tibial lengthening. The Ilizarov method is the most important alternative for the orthopaedic surgeon in the reconstruction of large osteoarticular defects of the skeleton. Key words: Osteoarticular defect, bone transport, tibiotalar fusion, the Ilizarov method, ankle Ilizarov Metodu ile Es Zamanli Artroez ve Kemik Uzatilmasi Ekstremitelerin buyuk osteoartikuler defektleri ortopedik cerrahinin oldukca guc olgularindandir. Iskelet sisteminin bu tur defektleri icin cesitli geleneksel tedavi yontemleri olsa da, basari orani dusuktur. Atesli silah yaralanmasina bagli tum distal tibia, distal fibula ve talus kubbesini iceren buyuk bir osteoartikuler defekte sahip olan 48 yasindaki hastanin Ilizarov yontemiyle tibial uzatma ve tibiotalar fuzyon ile tedavisini rapor ediyoruz. Secilen tedavi yontemi sadece es zamanli yapilmis bir artrodez ve ekstremite uzatma islemi degildi. Butun sag distal tibia ve ayak bilegi bolgesi tibiotalar fuzyon ve proksimal tibial uzatma yapilarak rekonstrukte edildi. Ilizarov yontemi iskelet sisteminin buyuk osteoartikuler defektlerinin rekonstruksiyonunda ortopedik cerrah icin en onemli alternatiftir. Anahtar kelimeler: Osteoartikuler defekt, kemik transportu, tibiotalar fuzyon, ayak bilegi

Geophysical modeling via simultaneous joint inversion of seismic, gravity, and electromagnetic data: Application to prestack depth imaging

Geophysical modeling of multiple geophysical parameters can take place reliably through the simultaneous joint inversion of the different geophysical domains. The desired objective is the derivation of a model expressing different geophysical properties of the Earth but, at the same time, showing consistency among the parameters. This concept, generally referred to as data integration, is widespread in geophysics but the way of achieving it is not obvious. Several authors have proposed different approaches where data, interpretation, and experience all contributed to the task. The result is that no general workflows could be defined that left ample margins for uncertainties and personal judgment.

Simultaneous Estimation of Torque and Angle of Human Elbow Joint by Using Ultrasound Echo

We propose a new method for joint angle and torque estimation by using ultrasound. The ultrasound is emitted from the surface of skin. The estimation is carried out based on the feature value extracted from the reflected wave from inside of living body. The feature value changes as the movement of the muscle relating to the joint. We conducted an examination of simultaneous joint torque and angle estimation in dynamic motion of human elbow joint. Neural network and Multiple linear regression was employed as the estimator. Correlation coefficients and Mean absolute error between estimated data and measured data were calculated. The results show that the estimation was successful, though the error increased with time course.

The Use of External Skeletal Fixation to Facilitate the Surgical Release of Wrist Flexion and Thumb Web Space Contractures

To evaluate the use of external fixation as a splint to keep the hand in the desired position after simultaneous joint and soft-tissue release in a single stage for treatment of first web space and wrist contractures. Six first web space adduction and 7 wrist flexion contractures were released surgically. All patients had prior unsuccessful surgery. After surgical release of the contracture and capsulotomy, external fixator pins were inserted into the first and second metacarpals to maintain thumb abduction and into the radius and second metacarpal to maintain wrist extension, followed by skin grafting. External fixation was followed by splinting. Results were based on persistence of contracture release, rate of complications, and functional outcome. Before surgery, the thumbs were contracted at an average of 0 degrees of adduction with no range of motion, and wrists were contracted between 85 degrees to 100 degrees of flexion. The duration of contracture and number of prior surgeries did not influence the amount of release obtained during the surgery. After 7 months to 7 years of follow-up of first web space contractures, the thumb was in an average of 55 degrees of palmar abduction. Patients were able to oppose and fully adduct. At long-term follow-up examinations of the wrist contractures, patients had the wrist in the neutral position (0 degrees) in the resting state, with active extension ranging between 5 degrees and 15 degrees and flexion ranging between 35 degrees and 45 degrees . In 1 patient the wrist was at 45 degrees of flexion in the resting state with an arc of motion of 20 degrees . In 1 patient the wrist contracted back to the preoperative position, requiring another surgery. All patients experienced increased activity and improvement in grasping objects at 6-month follow-up evaluations. Complications included 3 pin site infections, 1 severe discomfort after 6 weeks, and 1 median nerve compression. All were treated successfully. External fixation can be used to maintain position in cases of first web space and wrist flexion contractures after surgical release, especially in patients for whom standard methods have failed. It is safe, efficacious, and well tolerated. Therapeutic IV.

Southern Quebec (Canada) summer-season heat spells over the 1941–2000 period: an assessment of observed changes

Summer-season (May–September) daily maximum temperature (Tmax) and daily minimum temperature (Tmin) observations and three types of heat spells obtained from these temperature observations at seven weather stations located in southern Quebec (Canada) for the 60-year period from 1941 to 2000 are studied to assess temporal changes in their characteristics (i.e. frequency of occurrence, seasonal hot days and extremal durations of heat spells). Type-A and Type-B heat spells are obtained respectively from Tmax and Tmin observations and Type-C heat spells from simultaneous joint observations of Tmax and Tmin using suitable thresholds and spells of duration ≥1-day and ≥3-day. The results of this investigation show that the majority of the selected percentiles (i.e. 5P, 10P, 25P, 50P, 75P, 80P, 90P, 92P, 95P, and 98P) of Tmax observations show a negative time-trend with statistically significant decreases (at 10% level) in some of the higher percentiles and in the maximal values at four out of seven stations. Almost all of the selected percentiles (same as for the Tmax) and the maximal and minimal values of Tmin observations show a positive trend, with statistically significant increases for all seven stations. Examination of frequencies of occurrence of heat spells, seasonal hot days and annual extremes of heat spell durations indicate that many of these characteristics of heat spells have undergone statistically significant changes over time at some of the stations for Type-A and Type-B heat spells as compared to Type-C heat spells. The Type-C heat spells are generally small in number and are found to be relatively temporally stable. More severe Type-C heat spells, i.e. the ones having Tmax and Tmin values simultaneously above very high thresholds and with duration ≥3-day have been rarely observed in southern Quebec.

P17.67 Patients' Outcome After Simultaneous Bilateral Total Hip and Knee Joint Replacements

P17.67 Patients' Outcome After Simultaneous Bilateral Total Hip and Knee Joint Replacements

Edge-preserving joint motion-disparity estimation in stereo image sequences

An energy-based joint motion and disparity estimation algorithm with an anisotropic diffusion operator is proposed to yield correct and dense displacement vectors. We propose two energy models; the joint estimation model and the simultaneous joint estimation model. In the joint estimation model, we compute the initial disparity in the current frame with the joint estimation constraint, using the left and right motions and the disparity in the previous frame; therefore, the model is prevented from being trapped in the local minima. Then, we regularize this disparity by using our proposed energy model. In the simultaneous joint estimation model, we propose an energy functional that consists of fidelity and smoothing terms for the left and right motions and the joint data terms. We estimate the left and right motions simultaneously in order to increase correctness. We use the Euler–Lagrange equation with variational methods and solve the equation with the finite difference method (FDM) to minimize the energy model. Experimental results show that the proposed algorithm provides accurate motion-disparity maps that reflect the constraints of motion and disparity, and preserve the discontinuities of the object boundaries well.

Blind Separation of Nonstationary Sources

We propose a blind separation technique for nonstationary sources that exploits both auto-terms and cross-terms of the time-frequency distributions. The technique is based on the simultaneous joint diagonalization and off-diagonalization of spatial time-frequency distributions. Computer simulations demonstrate the superiority of the approach in comparison with other time-frequency based methods.

A novel device for active shoulder rehabilitation with glenohumeral traction or compression

The equipment available for rehabilitation of patients with joint conditions still lacks a device that, in common with usual physiotherapeutic measures (manipulation, proprioceptive neuromuscular facilitation, Bobath therapy), is based on traction and/or compression or oscillating forms. The novel "Shoulder Rotator" is such a simple device for the variable treatment of shoulder disorders in all three spatial dimensions. After individual instruction, the patient performs rotating glenohumeral exercises with simultaneous glenohumeral joint traction, compression, or oscillations against static or dynamic resistance. The "Shoulder Rotator" is similar to the established continuous passive motion device for the shoulder and is mounted on a mobile chair. The electronic device control is computerised and permits a wide variety of treatment options, individual regimes, and documentation. The oscillating, compression/distraction mode of operation provides an analgesic effect. The isolated compression mode along the rotatory axis enables conditioning of joint proprioception. The distraction mode along the rotatory axis facilitates muscular relaxation. Resistive rotatory exercises strengthen the rotatory glenohumeral muscles and help centre the humeral head in the glenoid. In addition to the advantage of adding documentation of treatment progress as required for evidence-based medicine, this novel device may bring about a cost-effective, genuine quality improvement in shoulder rehabilitation.

Locations of mid‐oceanic earthquakes constrained by seafloor bathymetry

Earthquakes associated with the creation of new oceanic crust are difficult to locate precisely because they normally occur far away from seismic stations. We assume that epicenters of these events can be constrained by seafloor topography and use the Harvard centroid moment tensor (CMT) focal mechanism of an interplate earthquake to relate the event to either a transform fault (a parallel in a coordinate system defined by the pole of rotation between two plates) or a mid‐oceanic ridge (a meridian). Using arrival times from the International Seismological Center (ISC) Bulletin, we have relocated about 1500 globally distributed events for the time period 1976–1998. The ISC locations can be as much as 70 km away from appropriate topographic features. Our new locations support that large interplate earthquakes occur on or very close to the primary bathymetric features. For earthquakes with unknown mechanism or magnitude below the CMT threshold or predate the CMT catalog, we use a simultaneous Joint Hypocenter Determination procedure with respect to the already relocated Master Events (JHDME). We invert for earthquakes first for the Romanche Fracture Zone (RFZ) and then for a region extending from 30°N to 30°S. Seismicity agrees well with the main active ridge or transform. However, a small number of events might be related to the secondary bathymetry features. The improved locations for mid‐oceanic earthquakes based on bathymetry could help improve our understanding of the oceanic crustal and deep Earth structure, seismic slip and budget constraint along plate boundaries, and dynamics of plate tectonics.

Joint imaging riometer—Incoherent scatter radar obser vations: A four-dimensional perspective on energetic particle input to the auroral mesosphere

The application of the cosmic noise absorption technique using riometers has markedly improved in recent years with the introduction of systems with multiple narrow beams (‘imaging’ riometers). One such instrument, using 49 beams, has been operating at Kilpisjärvi, Finland, since September 1994. The beam pattern encompasses the location of the EISCAT incoherent scatter radar facility, offering prospects for studies using simultaneous joint observations. The radar can monitor the height and time variation of electron density in the D-region while the imaging riometer data provide the horizontal distribution of energetic charged particle precipitation. The latter is essential in order to correctly identify whether variations in the radar measurements are truly temporal, or actually spatially-confined structures moving through the radar beam. We present examples of such joint observations, and discuss the advantages of this approach compared with the capabilities of the two individual techniques alone.

Aid to families with dependent children (AFDC) and non-marital births in the USA: an examination of causality

Utilizing a sample of 2964 unmarried women over the period 1979-88 from the US National Longitudinal Survey of Youth, a test was performed to determine the causal direction of relationship between receipt of aid to families with dependent children (AFDC) and the decision to have a non-marital birth. The existence of ‘causality’ is defined as the lack of a simultaneous relationship or joint dependency between these variables. One of the most interesting findings was a failure to reject the hypothesis that these choices are jointly determined. Both were found to depend upon variables that are demographic, economic, personal, and family-related. The profiles derived from the specification and estimation of a simultaneous equation system with discrete endogenous variables depict a woman whose fertility and economic decisions were predominantly based on economic deprivation, demographic situation and family instability.

Modulation/microwave integrated digital wireless developments

Simultaneous study and joint optimization of digital modulation techniques and of microwave components, presented in this paper, lead to spectrally efficient, high capacity, fast transmission, and throughput rate wireless systems. The choice of a particular modulation/demodulation (modem) technique has a major impact on the overall microwave system design, transceiver architecture and on the choice of all intermediate frequency (IF) as well as radio frequency (RF) component specifications. The performances of the most frequently used digital modulation techniques, including /spl pi//4-DQPSK, conventional BPSK, DQPSK, GMSK, GFSK, 4FSK, and FQPSK systems are compared. Study of crosscorrelated quadrature modulated GMSK systems used in GSM, PCS-1900, and other standards indicate that the subject technologies applied to GMSK improve the performance of these systems. We demonstrate that with the patented family of digitally modulated Feher's FQPSK systems, the power efficiency of conventional QPSK systems, which require linear microwave amplifiers, can be increased by about 300%, and the spectral efficiency of standardized nonlinearly amplified microwave integrated circuit GMSK systems can be increased by 60-200%. Similar advantages are obtained with our new FBPSK over BPSK modulated systems. >

Multivariate Estimation of Conditional Performance Measures in Regenerative Simulation

SYNOPTIC ABSTRACTA “conditional” performance measure for a stochastic system is, by definition, the mean of a sequence of stationary observations conditioned on the occurrence of a particular event or system state. (For example, the mean waiting times of customers in each priority class in a priority queueing system are “conditional” performance measures.) Conditional performance measures are useful since they give more detailed information about the system.Methods for computing approximate large-sample simultaneous confidence intervals and joint confidence regions for conditional performance measures are presented and evaluated in this paper. Empirical studies on two systems for which theoretical values are available show that this methodology permits reliable simultaneous confidence intervals to be computed from samples of moderate size; however, valid joint confidence regions require larger sample sizes.

Cinematographical Methods to Assess Associated Movements in Children

This pilot study was conducted to test the usefulness of angle-angle diagrams and phase plane plots obtained through high-speed cinematographical methods for making graded assessments of associated movements in children. Kinematic data at the shoulder, elbow, and ankle joints of normal and motorically awkward children (5-7 years old) were obtained from digitized films of normal and heel walking trials on a motor driven treadmill. A computer program was developed to smooth, calculate, differentiate, and plot data. Angle-angle diagrams depicting simultaneous joint angular displacements of (a) shoulder versus ankle and (b) elbow versus ankle revealed graded differences in decoupling of joint motion, limb excursions, and joint range-of-motion changes between the 5-year-old, 7-year-old awkward, and 7-year-old normal subject. Phase planes of the shoulder, elbow, and ankle joint were obtained by plotting joint angular displacement against joint angular velocity. Differences in size, shape, and looping behavior showed the quantity of change and whether the changes were gradual or sudden. This noninvasive methodology and eventual standardization of angle-angle diagrams and phase planes could prove to be useful in providing more precise diagnoses of associated movements and other subtle movement disorders.

Articulated Figure Positioning by Multiple Constraints

A problem that arises in positioning an articulated figure is the solution of 3D joint positions (kinematics) when goal positions, rather than joint angles, are given. If more than one such goal is o be achived, tge problem is often solved interactively by positioning or solving one component of the linkage, then adjusting another, then redoing the first, and so on. This iterative process us skiw abd tedious. We present a method that automatically solves multiple simultaneous joint position goals. The user interface offers a six-degree-of-freedom input device to specify joint angles and goal positions interactively. Examplesare used to demonstrate the power and efficiency of this method for keypositon animation.