Boundary Misalignment Research Articles

Flexural–torsional modeling and equilibria of three-dimensional axially moving beams

The equilibrium equations for the coupled flexural–flexural–torsional–extensional mechanics of an axially moving beam with initial tension are studied. The form of the governing equations is discussed, and numerical solutions are presented for two types of boundary misalignment that both result in out-of-plane flexural–torsional equilibria. Solutions to the governing equations are obtained while retaining all non-linear terms. With all non-linear terms, the governing equations cannot be expressed in first-order form and appear to be missing boundary conditions, thus complicating the numerical solution. The results are compared to an existing reduced model, thereby confirming previously employed simplifying assumptions. Finally, an alternative form of the equations of motion is derived that are simpler and consists of only polynomial non-linearities. The new equations are shown to capture the behavior studied with only a small reduction in accuracy compared to other models.

Energy Efficiency Analysis through Misalignment on New Design of Hexagonal Coil Array in Wireless Power Transfer

The global transportation revolution accelerates the growth of the Electric Vehicle (EV) market. Wireless Power Transfer Technology (WPT) is part of an alternative solution to replace charging by cable. In its implementation the driver's parking behavior affects Power Transfer Efficiency (PTE) due to frequently misalignment. A new coil array design proposed to optimize PTE and reduce the size of receiver coil. Receiver and transmitter circuits designed to simulate parking conditions and parking lots in small scale settings to get PTE data. Experimental results show that PTE increased by 10% in the center of the coil design and 82% during misalignment on a radius array against single loop coil. In the area of Misalignment tangential boundary, efficiency increased by 5-10% compared to circular coil arrays. The proposed novel coil series achieves a higher overall PTE than a single coil design and an increase in PTE in the tangential boundary misalignment when compared to circular coil arrays.

A Robust Regularizer for Multiphase CT.

Joint image reconstruction for multiphase CT can potentially improve image quality and reduce dose by leveraging the shared information among the phases. Multiphase CT scans are acquired sequentially. Inter-scan patient breathing causes small organ shifts and organ boundary misalignment among different phases. Existing multi-channel regularizers such as the joint total variation (TV) can introduce artifacts at misaligned organ boundaries. We propose a multi-channel regularizer using the infimal convolution (inf-conv) between a joint TV and a separable TV. It is robust against organ misalignment; it can work like a joint TV or a separable TV depending on a parameter setting. The effects of the parameter in the inf-conv regularizer are analyzed in detail. The properties of the inf-conv regularizer are then investigated numerically in a multi-channel image denoising setting. For algorithm implementation, the inf-conv regularizer is nonsmooth; inverse problems with the inf-conv regularizer can be solved using a number of primal-dual algorithms from nonsmooth convex minimization. Our numerical studies using synthesized 2-phase patient data and phantom data demonstrate that the inf-conv regularizer can largely maintain the advantages of the joint TV over the separable TV and reduce image artifacts of the joint TV due to organ misalignment.

Enhanced thermoelectric performance in single-crystal-like semiconducting flexible GaAs films

With the advancement of nano-technology and push toward flexible electronics, the opportunity to generate electricity using solid-state devices has ushered tremendous research interest in improving the thermoelectric (TE) properties of flexible semiconducting materials. The majority of research done so far was focused on finding suitable doping schemes for all-organic flexible substrates or mixing organic and inorganic components to obtain flexible substrates with an optimized thermoelectric performance. Unfortunately, their performance is limited by their low power factor (PF) values and often suffers from degradation issues due to the organic component that limits them to low temperature applications. Here, through coupled microstructural and thermoelectric analysis, we show how to overcome these limitations by introducing a new inorganic GaAs flexible substrate with enhanced TE performance. We show that these flexible thin films are single-crystal-like biaxially textured with low angle grain boundary misalignment; and charge transport is dominated by multi- valley electron conduction. This results in a PF ∼1300 µW/mK2, the highest value for non-toxic inorganic flexible thin films and an estimated 3-fold enhancement in the figure of merit compared with bulk GaAs. We present the temperature-dependent experimental PF, mobility, and carrier concentration data coupled with the theoretical models to elucidate the charge transport characteristics of this new class of films. Moreover, these unique charge transport characteristics are material growth dependent, and thus, such novel thermoelectric properties are expected in different material systems.

The emergence of health technology organizations among institutional healthcare and economic actors

Few studies have considered the creation of health technology organizations where the entrepreneurs seize opportunities, create their entrepreneurial organization and provide it with legitimacy, and examined the triggers, constraints and pressures involved in this process. To study the emergence of such firms, we performed semistructured interviews with 20 entrepreneurs and strategic partners involved in the development and commercialization of health technologies. For each stage of the firm emergence process, we identified triggers and enablers, as well as barriers and constraints encountered by entrepreneurs, and pressures originating from institutional actors. We found that each stage of startup emergence had triggers where the entrepreneur faced a conflicting situation in the form of boundary misalignment, competing technologies, poor performances, and resource asymmetry. Each topic is examined in the light of neo-institutional theory and finally replaced within a larger process in which the entrepreneur addresses market and healthcare system needs and interacts with other actors. In each stage, we identified a predominant institutional process taking place, whether it was decoupling, organizational field influence or legitimation seeking. The present study aimed at understanding the process by which an opportunity is seized, an organization is created and an institution as big as a healthcare system is approached. The results may help entrepreneurs and decisionmakers understand the strategies engaged following pressures from the healthcare organization. Likewise, it could increase investors’ awareness of the emergence process of health tech businesses and stimulate mutual understanding between entrepreneurs, and economic and healthcare actors.

Are China's provincial boundaries misaligned?

Using geographic information systems and digital elevation data, we investigate the hypothesis that the imperial Chinese state manipulated provincial borders to weaken the autonomy of Chinese regions. We find that China's present-day provincial borders, whose origin can be traced back to the thirteenth century, are highly misaligned with respect to physiographic features along China's North-South political fault line. Elsewhere, in regions that historically did not pose a fundamental threat to central authority, the degrees of misalignment are considerably lower. We interpret these findings as evidence of strategic manipulation of provincial boundaries. Our findings cast light on the spatial distribution of boundary misalignment and help identify the areas where the socioeconomic ramifications of misalignment—such as recurring cross-border pollution and inter-community disputes—are likely to be present.

View synthesis with 3D object segmentation-based asynchronous blending and boundary misalignment rectification

Numerous depth image-based rendering algorithms have been proposed to synthesize the virtual view for the free viewpoint television. However, inaccuracies in the depth map cause visual artifacts in...

Misalignment of watershed and jurisdictional boundaries: the importance of scale

The misalignment of the boundaries of watersheds and jurisdictions is cited often as a barrier to effective water governance, but the validity of the assertion depends on watershed scale and the decisions or processes involved. The paper probes these decision processes and their alignment with scales of natural watersheds and with governance processes. Two examples from the USA provide context and data to inform the discussion, one from the humid eastern part and one from the drier western part. Ultimately, the spatial and governance scales determine the complexity of decisions. The major issue is the level and nature of negotiations and how stakeholders communicate and work with each other to resolve issues in a form of pragmatic federalism, where the concept merges into decentralization to the subwatershed level. At smaller scales, negotiations can be worked out in person-to-person venues but at larger scales institutions have their own trajectories and inertia. Ultimately, watershed boundaries can be effective for joint planning and assessment, but decisions follow governance patterns. Basin boundaries do provide venues for coordination mechanisms to mediate conflicts.

경계 잡음 제거를 위한 2단계 경계 탐색 기반의 깊이지도 전처리 알고리즘

DIBR(Depth Image Based Rendering)을 이용한 영상 합성 시에 발생하는 경계 잡음은 원래 전경 영역에 속하던 화소가 배경으로 흩어져 나와 생성된 잡음이며, 이는 주로 참조 영상과 깊이지도 간 경계 불일치나 참조 영상에서의 블러링 때문에 발생된다. 영상 합성 과정에서 발생된 홀 영역은 일반적으로 주위 화소를 이용하여 채워지게 되므로, 홀에 인접한 경계 잡음은 합성 영상의 화질을 저하시키는 주요 원인으로 작용한다. 이 문제를 해결하기 위해 본 논문은 깊이지도의 전처리를 이용한 새로운 경계 잡음 제거 알고리즘을 제안한다. 기존의 전처리 기법들은 경계 불일치에 따른 경계 잡음의 제거를 위해 참조 영상과 깊이지도의 경계가 일치되도록 깊이지도를 수정한다. 그러나 대부분의 기존 기법들이 신호 기울기 기반의 단순 경계 탐색 알고리즘에 기반을 두고 있어 블러링이 존재하는 경계에서는 탐색 성능의 저하가 나타난다. 제안 알고리즘은 이의 해결을 위해 2단계 경계 탐색을 이용함으로써 이행 영역과 배경 영역 간 경계를 보다 효과적으로 탐색할 수 있는 구조를 제안하였다. 실험 결과를 통해 제안 알고리즘이 기존 알고리즘에 비해 우수한 경계 잡음 제거 성능을 가짐을 보인다. The boundary noise in image syntheses using DIBR consists of noisy pixels that are separated from foreground objects into background region. It is generated mainly by edge misalignment between the reference image and depth map or blurred edge in the reference image. Since hole areas are generally filled with neighboring pixels, boundary noise adjacent to the hole is the main cause of quality degradation in synthesized images. To solve this problem, a new boundary noise removal algorithm using a preprocessing of the depth map is proposed in this paper. The most common way to eliminate boundary noise caused by boundary misalignment is to modify depth map so that the boundary of the depth map can be matched to that of the reference image. Most conventional methods, however, show poor performances of boundary detection especially in blurred edge, because they are based on a simple boundary search algorithm which exploits signal gradient. In the proposed method, a two-step hierarchical approach for boundary detection is adopted which enables effective boundary detection between the transition and background regions. Experimental results show that the proposed method outperforms conventional ones subjectively and objectively.

The Effects of Syllable Boundary Ambiguity on Spoken Word Recognition in Korean Continuous Speech

The purpose of this study was to examine the syllable-word boundary misalignment cost on word segmentation in Korean continuous speech. Previous studies have demonstrated the important role of syllabification in speech segmentation. The current study investigated whether the resyllabification process affects word recognition in Korean continuous speech. In Experiment I, under the misalignment condition, participants were presented with stimuli in which a word-final consonant became the onset of the next syllable. (e.g., /k/ in belsak ingan becomes the onset of the first syllable of ingan `human`). In the alignment condition, they heard stimuli in which a word-final vowel was also the final segment of the syllable (e.g., /eo/ in heulmeo ingan is the end of both the syllable and word). The results showed that word recognition was faster and more accurate in the alignment condition. Experiment II aimed to confirm that the results of Experiment I were attributable to the resyllabification process, by comparing only the target words from each condition. The results of Experiment II supported the findings of Experiment I. Therefore, based on the current study, we confirmed that Korean, a syllable-timed language, has a misalignment cost of resyllabification.

A Geostatistical Approach to Large‐Scale Disease Mapping with Temporal Misalignment

Temporal boundary misalignment occurs when area boundaries shift across time (e.g., census tract boundaries change at each census year), complicating the modeling of temporal trends across space. Large area-level datasets with temporal boundary misalignment are becoming increasingly common in practice. The few existing approaches for temporally misaligned data do not account for correlation in spatial random effects over time. To overcome issues associated with temporal misalignment, we construct a geostatistical model for aggregate count data by assuming that an underlying continuous risk surface induces spatial correlation between areas. We implement the model within the framework of a generalized linear mixed model using radial basis splines. Using this approach, boundary misalignment becomes a nonissue. Additionally, this disease-mapping framework facilitates fast, easy model fitting by using a penalized quasilikelihood approximation to maximum likelihood estimation. We anticipate that the method will also be useful for large disease-mapping datasets for which fully Bayesian approaches are infeasible. We apply our method to assess socioeconomic trends in breast cancer incidence in Los Angeles between the periods 1988-1992 and 1998-2002.

Mutual‐information‐based image to patient re‐registration using intraoperative ultrasound in image‐guided neurosurgery

An image-based re-registration scheme has been developed and evaluated that uses fiducial registration as a starting point to maximize the normalized mutual information (nMI) between intraoperative ultrasound (iUS) and preoperative magnetic resonance images (pMR). We show that this scheme significantly (p<0.001) reduces tumor boundary misalignment between iUS pre-durotomy and pMR from an average of 2.5 mm to 1.0 mm in six resection surgeries. The corrected tumor alignment before dural opening provides a more accurate reference for assessing subsequent intraoperative tumor displacement, which is important for brain shift compensation as surgery progresses. In addition, we report the translational and rotational capture ranges necessary for successful convergence of the nMI registration technique (5.9 mm and 5.2 deg, respectively). The proposed scheme is automatic, sufficiently robust, and computationally efficient (<2 min), and holds promise for routine clinical use in the operating room during image-guided neurosurgical procedures.

Flexural-torsional buckling of misaligned axially moving beams: II. Vibration and stability analysis

This paper addresses the stability and vibration characteristics of three-dimensional steady motions (equilibrium configurations) of translating beams undergoing boundary misalignment. System modeling and equilibrium solutions for bending in two planes, torsion, and extension were presented in Part I of the present work. Stability is determined by linearizing the equations of motion about a steady motion and calculating the eigenvalues using a finite difference discretization. For the case of no misalignment, the calculated eigenvalues are compared to known values. When the beam is misaligned, the system initially enters a planar configuration and the results indicate that the planar equilibria lose stability after the first bifurcation point. Eigenvalue behavior of the planar equilibria after the first bifurcation point is shown to be strongly influenced by translation speed. Eigenvalue behavior about non-planar equilibria and vibration modes about selected equilibria are also presented.

Role of intergranular silver in modulating the aperiodicity in disordered Josephson junction arrays: impact on relaxation of intergranular critical state

Relaxation of the intergranular critical state has been observed at a very low applied magnetic field (10–50 Oe) over a temperature regime of 20–77 K in bulk polycrystalline YBa 2Cu 3O 7− x (YBCO) and Bi 1.75Pb 0.35Sr 2Ca 2Cu 3O 10+ x (BPSCCO) samples. In such a disordered Josephson junction network, the relaxation is slower than the intragranular relaxation and, hence, it yields higher flux pinning energy U 0 than the corresponding intragranular values. Silver addition seems to have given rise to much uniformity in the grain boundary characteristics which results in sharp drop in the flux pinning energy since it depends on the variation of the junction coupling energy E J across the network. While U 0≈0.5 and 0.55 eV for the parent BPSCCO and YBCO samples, respectively, in silver added (10–15 wt.%) samples the corresponding values are ∼0.15 and ∼0.27 eV. The distribution functions m( U) for the flux pinning energy and n( θ) for the grain boundary misalignment angle θ have been evaluated from the experimentally observed patterns of magnetic relaxation and variation of the grain boundary critical fields with temperature. The distribution functions become narrower in the case of silver added samples reflecting a reduction in the degree of disorder. The variation of the effective vortex mass m * with the variation in the degree of disorder is observed. Considering the width of the superconducting transition ΔT c as the measure of the degree of disorder (inhomogeneity), it has been shown that the transport critical current density J c follows a relationship J c∼exp(− ΔT c) while the pinning energy U∼ ΔT c. These relations may help in devising a suitable strategy for achieving the desired effect: high J c yet slower decay rate, i.e., large U.

Flux pinning and critical currents in a disordered grain boundary model

Abstract The pinning potential and critical currents of a S-S′-S junction with a slab geometry, in the presence of penetration depth fluctuations in S′, are evaluated in the London limit. This junction serves as a model for flux pinning grain boundaries. Disorder induced pinning is found to extend into the S domains over a distance comparable to the penetration depth. For “realistic” parameters, the calculated critical currents have a weak dependence on the grain boundary misalignment angle and high values. Comparison with relevant data is discussed.