Boundary Reconstruction Research Articles

Experimental Validation for Microwave Based Real-time Monitoring for Microwave Ablation Treatment.

Microwave ablation (MWA) is one of the most promising treatment tool to achieve a minimal invasion for human body. For safety and effective ablation for cancerous tissue, the accurate and real-time imaging for a temporal evolution of the ablation zone is highly demanded. This paper assumes the microwave based MWA monitoring, and introduces the novel boundary reconstruction algorithm, which has been demonstrated to achieve a real-time, accurate and noise-robust characteristic. This paper also newly introduces the S11 based complex permittivity estimator, which is necessary for estimating the ablation boundary. The both finite difference time domain (FDTD) based 3-D numerical test and the experimental investigation demonstrate that the proposed method provides accurate and high-speed 3-D imaging for the ablation zone.

Interface structure and planar defects in the heterostructure of pyrochlore-type (Ca,Ti)2(Nb,Ti)2O7 film on SrTiO3 (0 0 1) substrate

Pyrochlore-type (Ca,Ti)2(Nb,Ti)2O7 thin film has been successfully prepared on (0 0 1)-oriented SrTiO3 substrate. The atomic-scale microstructure properties of the heterostructure have been investigated by advanced electron microscopy techniques. It is found that the (Ca,Ti)2(Nb,Ti)2O7 thin film is polycrystalline and an intermediate layer of perovskite-type Ca(Nb,Ti)O3 with a few unit cell thicknesses forms at the (Ca,Ti)2(Nb,Ti)2O7/SrTiO3 interface. In the (Ca,Ti)2(Nb,Ti)2O7 thin film, planar defects including {1 1 1}-type stacking faults, reflection twin and glide-reflection twin appear. The stacking faults have a projected displacement vector of (a/8)〈112〉. Cation segregation and boundary reconstruction occur at the twin boundaries and the stacking faults, which cause the change of the local stoichiometry and are believed to affect the electrical properties of the film.

Detailed Structure and Plate Reconstructions of the Central Indian Ocean Between 83.0 and 42.5 Ma (Chrons 34 and 20)

AbstractThe Central Indian Ocean, namely the Central Indian, Crozet, and Madagascar basins, formed by rifting and subsequent drifting of India (now Capricorn), Antarctica, and Africa (now Somalia). We gathered a comprehensive set of sea surface magnetic anomaly profiles over these basins and revisited location and identification of magnetic isochrons between C34ny (83.0 Ma) and C20ny (42.536 Ma) using the objective analytic signal technique. We present high‐resolution magnetic isochrons for 29 periods based on ~1,400 magnetic anomaly picks. From the conjugate sets of picks, we derive two‐plate finite rotation parameters for both the Capricorn‐Antarctica and Capricorn‐Somalia motions. These finite rotations are compared to three‐plate reconstructions of the plate boundaries between the Capricorn, Antarctica, and Somalia plates, constrained by the closure of the Indian Ocean Triple junction. In general, the three‐plate reconstructions slightly overrotate the reconstructed isochrons with respect to the Capricorn‐Antarctica and Capricorn‐Somalia two‐plate reconstructions. Conversely, the two‐plate reconstructions for Somalia‐Antarctica slightly underrotate the isochrons compared to the Capricorn‐Antarctica‐Somalia three‐plate reconstructions. We suspect that the discrepancies between the two‐plate and three‐plate methods result from the recent seafloor deformation in the Capricorn‐India diffuse plate boundary and/or from the contrasted nature and geometry of magnetic isochrons at different spreading rates (i.e., magnetic structure of the three spreading centers). Three‐plate reconstructions better constrain the closure of the triple junction but spread any misfit among all three plate boundaries. When enough quality data are available, two‐plate reconstructions may lead to more realistic plate motion estimates from which additional geological problems can be identified and solved.

First implementation of plasma shape GAP control method in EAST

Preliminary implementation of plasma GAP shape control in EAST is presented. Compared with ISOFLUX method, GAP control could work together with not only real-time equilibrium reconstruction but also real-time boundary reconstruction. Based on the plasma response matrix, the GAP controller is designed and the PID parameter has been optimized for EAST plasma shape control. P-EFIT provides real-time gap calculation and GAP controller is integrated into EAST PCS. Successful plasma shape with GAP control scheme is achieved in EAST 2018 summer campaign. Experimental results prove that GAP control algorithm and controller could achieve similar control ability as ISOFLUX and provide an option for shape control with optical-based boundary reconstruction in EAST and future device CFETR.

Plasma boundary reconstruction in JET by magnetic measurements

The reconstruction of the plasma boundary is a critical issue in the monitoring and control of fusion devices. The problem can be solved by the solution of force balance magneto-hydro-dynamic equations but, unfortunately, the computing burden can be not compatible with the needs of the on-line control. Advanced electromagnetic modelling of the plasma, based on surface equivalent currents recently proposed, can be a compromise between accuracy and promptness especially when a fully 3D treatment is necessary or foreseen. A procedure able to take advantage of the magnetic measurements to provide a plasma boundary reconstruction is here presented. The paper includes the illustration of a first assessment carried out on the JET by using the data of a standard axisymmetric shot, with the aim to check the coherence between the experimental evidence and the numerical procedure.

How to optimize the therapeutic effect of free autogenous fibula graft and wrist arthroplasty for giant cell tumors of distal radius?

The purpose of this study is to retrospectively analyze the clinical efficacy of free fibula autograft and wrist arthroplasty in the treatment of giant cell tumors (GCT) of distal radius. We retrospectively reviewed 26 patients with GCT of distal radius who underwent free autogenous fibula graft and wrist arthroplasty for repairing residual defect after en-block resection. The length of the fibula graft was 8.2 cm (6-10 cm). Postoperative follow-up regularly for an mean of 66.9 months. Bone healing was assessed by radiographs, pain was assessed by Visual Analog Scale (VAS) score and limb function was evaluated by Musculoskeletal Tumor Society (MSTS) score and disabilites of the arm, shoulder and hand (DASH) score. The range of motion (ROM) of wrist and grip strength were also evaluated. There were four males and 22 females with an mean age of 36.7 years (19-60 years); the mean length of lesions was 4.8 cm (2.3-6.6 cm); 21 primary cases and five recurrent cases; eight cases of Campanacci Grade II, 18 cases of Grade III. We had no postoperative lung metastasis and only one case had a local recurrence, three cases (11%) with subluxation of lower ulnoradial joints and five cases (19%) showed narrowing of wrist joint space. The mean postoperative VAS pain score was 0.7 ± 0.7 and grip strength retained 71% of the normal hand, MSTS score was 27.7 ± 1.1 and DASH score was 9.0 ± 3.7. The ROM of the involved wrist only slightly restricted and no donor complications. Postoperative wrist joint function was significantly improved. Strict surgical resection boundary and solid reconstruction of wrist joint capsule are the key to achieving excellent oncological prognosis and function of distal radius GCT.

Tenure Conflicts Resolution Of Colol Custom Community In Ruteng Recreation Park, Nusa Tenggara Timur

AbstractDetermination of the Ruteng Recreation Nature Park had caused conflicts over tenure for Colol custom community have been in and around the area since before the establishment. Conflict was due for access to agricultural land use and timber had closed by the management. The conflict resolution involves three elements, namely the government, customs and religion which are called the three pillars. This study aims to understand the stages of the tenure conflict, relevant stakeholders and the conflict resolution. The study was conducted Colol village in April to May 2016. Acquisition of data using observation, in-depth interviews with a purposive and snowball and secondary data. Analysis of data using conflict tree analysis, stakeholders and mapping conflicts. The results showed that the cause of the conflict is the difference in value systems that implicates disagreement land status and boundaries as well as the uncertainty of access due to rights issues and access. Conflict resolution is required is to build trust between the parties, improve communication to reduce the differences in perception, increased involvement of indigenous peoples in the management of Ruteng Recreation Park, reconstruction of recreation park boundaries involving the parties, especially the major stakeholders and optimizing the coordination and communication between the parties.Colol Custom Community determine their traditional territory option to pull out of the Ruteng Recreation Park.Â

A Robust Inclusion Boundary Reconstructor for Electrical Impedance Tomography With Geometric Constraints

As a nondestructive, nonradioactive, and high temporal resolution technique, electrical impedance tomography (EIT) has potential applications in industrial and biomedical imaging. A novel geometrically constrained boundary reconstructor (GCBR) is presented for EIT. It can directly calculate the boundary of the target inclusions embedded into a homogeneous background conductivity and is robust to noise. The proposed GCBR depends on a specially designed energy function, which consists of the residual term and the geometric constraints’ term. The residual term drives the estimated inclusion boundary to the targets. The geometric constraints’ term regularizes the estimations and automatically excludes the meaningless boundary guesses from the candidate solution. A set of numerical tests are conducted to discuss the key factors influencing the boundary reconstruction performance. A set of experimental tests are conducted to evaluate the performance of the proposed GCBR. The position, size, and shape of the target inclusions are well reconstructed from the real data. The mean position error and mean Hausdorff distances between the target and reconstructed boundaries are 0.39% and 2.2% of the maximal observation diameter, respectively. The mean area errors and the mean area of the symmetric difference between the target and reconstructed inclusion regions are 0.32% and 2.54% of the total observation area, respectively.

Numerical simulations of shock/obstacle interactions using an improved ghost-cell immersed boundary method

An improved ghost-cell immersed boundary method coupled with a high-order finite difference scheme is currently proposed to numerically simulate the reflected shock/boundary layer interaction in a wavy-wall tube. The main improvement of current algorithm involves the particular treatment of the solid boundary reconstruction procedure by using both ghost points in solid domain and forcing points in fluid domain together. Owing to this kind of improvement operation, the amount of points used to recover the solid boundary increases greatly and will inevitably promote the accuracy of solid boundary reconstruction, which will play a significant role in the current high-order accurate numerical simulation. A typical validation case of 2-dimensional shock/circular cylinder interaction is conducted and demonstrate that the current improved numerical method can be used to capture the flow details such as shock bifurcation and small vortex very well and improve the numerical precision greatly. The improved method is then applied to numerically investigate the effects of boundary layer on the propagation of the shock in a wavy-wall tube. It is observed that, at low Mach number, the existence of boundary layer has little effect on the shock propagation. As the Mach number increases to 1.9, some certain complicated flow features will occur due to the enhanced boundary layer effects. In the early stage, the flow structures are nearly the same as those without the boundary layers. In the transition stage, a high-speed shear band behind the leading shock is observed and finally evolves into a worm-like structure, whose instability is illustrated by qualitative assessment on its flow features. In the developing stage, a remarkable shock bifurcation phenomenon is present and the worm-like structures will start shedding regularly, which will induce a series of scattering-like waves and asymmetrical flow fields. These characteristics demonstrate that the bifurcated shock waves located in upper and lower walls of the wavy-wall shock tube act as a primary trigger to gradually destabilize the shocked flow.

Reconstruction of the red-white boundary with pink composite

The composition of smile architecture includes pink gingiva and white tooth structure which gives an esthetic appearance. As age advances, gingival recession is seen which contributes to dentinal hypersensitivity and unsightly smile esthetics. Due to this, increasing number of patients are seeking dentists for the absence of pink-colored gingiva. Pink composites are gingival-colored composites that help to create a life-like tooth easily by reconstructing the red-white boundary with superior esthetics. This material provides long-lasting, high esthetic restorations with low abrasive values and high compressive and transverse strength. This shares a case report on how pink composites help in reconstructing the red-white boundary.

Application and numerical error analysis of multiscale method for air flow, heat and pollutant transfer through different scale urban areas

There is an increasing concern on the effect of the outdoor environment on the indoor air quality (IAQ) through ventilation. In urban areas, the physical phenomenon that the air pollutants pass over the neighborhood scale–street scale–indoor scale, and affect the health of the residents belongs to multiscale problems. The adopted multiscale method models the problem in nesting grid system approach by solving from top (entire domain with relative coarse grids) to down (subsequent sub-domains with finer grid). In this paper, a 3-D multiscale model with Richardson number (Ri) equal to 0.85 was firstly established to investigate the above multiscale phenomenon, then evaluated by comparing with the full-scale intensive simulation, since our previous study showed that when Ri ≤ 0.85 the standard k-ɛ turbulence model can better predict the flow and temperature fields. The numerical error analysis of the multiscale method was conducted by considering the effects of two aspects (boundary condition interpolation schemes and sub-domain partitioning) on the regularity of error production and transfer. Results show that the applied multiscale method can save 83.8% computing time. Furthermore, it can be concluded that among the three interpolation schemes for the boundary reconstruction the linear and spline interpolation methods are appropriate while the nearest method should not be applied because of its 1st-order accuracy. If insensitive interfaces are chosen as the partitioning interfaces of the lower-scale domain the computational accuracy of the multiscale method can be greatly improved.

Tailoring the mechanical anisotropy of sintered NdFeB magnets by Pr[sbnd]Cu grain boundary reconstruction

Pr83Cu17 (wt%) grain boundary reconstruction was applied to prepare sintered NdFeB magnets. The effects of addition amount and annealing on the bending strength were investigated. The results show that Pr83Cu17 can not only effectively enhance the bending strength, but also change the mechanical anisotropy in two directions parallel and perpendicular to c-axis. The bending strength perpendicular to c-axis reaches 404 MPa in 10 wt% addition magnet, higher than 348 MPa along parallel direction. This change is attributed to the preferred distribution of boundary phases, i.e., ductile (Nd,Pr)FeCu phase along perpendicular direction to c-axis and (Nd,Pr)-Fe phase along parallel direction. Moreover, the Cu migration during 480 °C annealing is found to be related to this boundary phase distribution.

An improved error bound on the boundary inversion for a sideways heat equation

We consider a new a-priori constraint for a sideways heat equation. This new constraint is used as a source condition for regularization resulting in a new computational method. An error estimate on this new regularization technique is obtained, showing an improvement over the existing methods by the traditional a-priori constraint at the boundary reconstruction.

Optical plasma boundary reconstruction based on least squares for EAST Tokamak

Reconstructing the shape and position of plasma is an important issue in Tokamaks. Equilibrium and fitting (EFIT) code is generally used for plasma boundary reconstruction in some Tokamaks. However, this magnetic method still has some inevitable disadvantages. In this paper, we present an optical plasma boundary reconstruction algorithm. This method uses EFIT reconstruction results as the standard to create the optimally optical reconstruction. Traditional edge detection methods cannot extract a clear plasma boundary for reconstruction. Based on global contrast, we propose an edge detection algorithm to extract the plasma boundary in the image plane. Illumination in this method is robust. The extracted boundary and the boundary reconstructed by EFIT are fitted by same-order polynomials and the transformation matrix exists. To acquire this matrix without camera calibration, the extracted plasma boundary is transformed from the image plane to the Tokamak poloidal plane by a mathematical model, which is optimally resolved by using least squares to minimize the error between the optically reconstructed result and the EFIT result. Once the transform matrix is acquired, we can optically reconstruct the plasma boundary with only an arbitrary image captured. The error between the method and EFIT is presented and the experimental results of different polynomial orders are discussed.

Blue Ocean Strategy: A Review of Literature

The market dynamics are changing abruptly due to the integration of technology and another macroeconomic factor into business. The organization which is considered as a market leader may also be investing enormous funds to stay competitive. The intent was not so convincing, because investing continuously to stay competitive is not a valid solution. The concept Blue Ocean Strategy was derived in 2005 and adds value by redefining the business boundaries. It highlights the importance of reconstruction of market boundaries which make competition irrelevant. The theory sounds exciting and selects a research topic to understand its possible way of integration in the current business process. The study of literature brings an understanding of how the different framework and tools can be applied in current business, to come out from competition and sail in an uncontested market. The review brings out an understanding of two exciting concepts of Blue Ocean Strategy, i.e., how to study factors of competition, and value innovation which is the cornerstone of Blue Ocean Strategy.

Atomic-scale 3D reconstruction of antiphase boundaries in GaP on (001) silicon by STEM

In order to overcome the limitations of silicon-based electronics, the integration of optically active III–V compounds is a promising approach. Nonetheless, their integration is far from trivial and control as well as understanding of corresponding growth kinetics, and in particular the occurrence and termination of antiphase defects, is of great relevance. In this work, we focus on the three-dimensional reconstruction of such boundaries in gallium phosphide from single scanning transmission electron microscopy images. In the high angle annular dark-field imaging mode, the appearance of these antiphase boundaries is strongly determined by the chemical composition of each atomic column and reflects the ratio of transmitted anti- to mainphase. Therefore it is possible to translate measured intensities to the depth location of these boundaries by utilizing simulation data. The necessary spatial resolution for these column-by-column mappings is achieved via electron optical aberration correction within the microscope. Hence, the complete 3D orientation of these defects can be measured at atomic resolution and correlated to growth parameters. Finally, we present a method to reconstruct large areas from well sampled images and retrieve information about complex embedded nanoscale structures at the atomic scale.

Crystallographic Reconstruction of Parent Austenite Twin Boundaries in a Lath Martensitic Steel

The study of post-transformation microstructures and their properties can be greatly enhanced by studying their dependence on the grain boundary content of parent microstructures. Recent work has extended the crystallographic reconstruction of parent austenite in steels to include the reconstruction of special boundaries, such as annealing twins. These reconstructions present unique challenges, as twinned austenite grains share a subset of possible daughter variant orientations. This gives rise to regions of ambiguity in a reconstruction. A technique for the reconstruction of twin boundaries is presented here that is capable of reconstructing 60° <1 1 1> twins, even in the case where twin regions are comprised entirely of variants that are common between the twin and the parent. This technique is demonstrated in the reconstruction of lath martensitic steels. The reconstruction method utilizes a delayed decision-making approach, where a chosen orientation relationship is used to define all possible groupings of daughter grains into possible parents before divisive decisions are made. These overlapping, inclusive groupings (called clusters) are compared to each other individually using their calculated parent austenite orientations and the topographical nature of the overlapping region. These comparisons are used to uncover possible locations of twin boundaries present in the parent austenite. This technique can be applied to future studies on the dependence of post-transformation microstructures on the special grain boundary content of parent microstructures.

Reconstruction of the Plasma Boundary of EAST Tokamak Using Visible Imaging Diagnostics

In order to reconstruct the plasma boundary directly and independently, a new method based on visible imaging diagnostics is developed for experimental advanced superconducting tokamak (EAST); its effectiveness has been verified by conducting offline experiments based on EAST's historical data. The offline boundary reconstruction results, including X-points, are compared to offline equilibrium fitting code (offline EFIT), which is a commonly used reconstruction method. With an average error of 1.5 cm, the total processing time for one frame is less than 2 ms by current software and hardware. When the camera sensor is not saturated, the algorithm is robust for different image intensities of the plasma discharge. The results of the boundary reconstruction by visible imaging diagnostics also show potential for real-time plasma control in a tokamak.

Robust sparse linear regression for tokamak plasma boundary estimation using variational Bayes

Precise control of the shape of plasma in a tokamak requires reliable reconstruction of the plasma boundary. The problem of boundary estimation can be reduced to a simple linear regression with a potentially infinite amount of regressors. This regression problem poses some difficulties for classical methods. The selection of regressors significantly influences the reconstructed boundary. Also, the underlying model may not be valid during certain phases of the plasma discharge. Formal model structure estimation technique based on the automatic relevance principle yields a version of sparse least squares estimator. In this contribution, we extend the previous method by relaxing the assumption of Gaussian noise and using Student’s t-distribution instead. Such a model is less sensitive to potential outliers in the measurement. We show on simulations and real data that the proposed modification improves estimation of the plasma boundary in some stages of a plasma discharge. Performance of the resulting algorithm is evaluated with respect to a more detailed and computationally costly model which is considered to be the “ground truth” The results are also compared to those of Lasso and Tikhonov regularization techniques.

An augmented Lagrangian trust region method for inclusion boundary reconstruction using ultrasound/electrical dual-modality tomography

The ultrasound/electrical dual-modality tomography utilizes the complementarity of ultrasound reflection tomography (URT) and electrical impedance tomography (EIT) to improve the speed and accuracy of image reconstruction. Due to its advantages of no-invasive, no-radiation and low-cost, ultrasound/electrical dual-modality tomography has attracted much attention in the field of dual-modality imaging and has many potential applications in industrial and biomedical imaging. However, the data fusion of URT and EIT is difficult due to their different theoretical foundations and measurement principles. The most commonly used data fusion strategy in ultrasound/electrical dual-modality tomography is incorporating the structured information extracted from the URT into the EIT image reconstruction process through a pixel-based constraint. Due to the inherent non-linearity and ill-posedness of EIT, the reconstructed images from the strategy suffer from the low resolution, especially at the boundary of the observed inclusions. To improve this condition, an augmented Lagrangian trust region method is proposed to directly reconstruct the shapes of the inclusions from the ultrasound/electrical dual-modality measurements. In the proposed method, the shape of the target inclusion is parameterized by a radial shape model whose coefficients are used as the shape parameters. Then, the dual-modality shape inversion problem is formulated by an energy minimization problem in which the energy function derived from EIT is constrained by an ultrasound measurements model through an equality constraint equation. Finally, the optimal shape parameters associated with the optimal inclusion shape guesses are determined by minimizing the constrained cost function using the augmented Lagrangian trust region method. To evaluate the proposed method, numerical tests are carried out. Compared with single modality EIT, the proposed dual-modality inclusion boundary reconstruction method has a higher accuracy and is more robust to the measurement noise.