Local Deviations Research Articles

Image Enhancement Method in Underground Coal Mines Based on an Improved Particle Swarm Optimization Algorithm

Due to the poor lighting conditions and the presence of a large amount of suspended dust in coal mines, obtained video has problems with uneven lighting and low differentiation of facial features. In order to address these problems, an improved image enhancement method is proposed. Firstly, the characteristics of underground coal mine images are analyzed, and median filtering is selected for noise removal. Then, the gamma function and fractional order operator are introduced, and an image enhancement algorithm based on particle swarm optimization is proposed. Finally, several experiments are conducted, and the results show that the proposed improved algorithm outperforms classical image enhancement algorithms, such as MSR, CLAHE and HF. Compared with the original image, the evaluation metrics of the enhanced Yale face images, including average local standard deviation, average gradient, information entropy and contrast, are improved by 113.1%, 63.8%, 22.8% and 24.1%, respectively. Moreover, the proposed algorithm achieves a superior enhancement effect in the simulated coal mine environment.

Persistent discrepancies in orbital morphology after surgical treatment of unicoronal craniosynostosis: a critical image-based analysis.

Unicoronal craniosynostosis (UCS) is characterized by complex orbital deformity and is typically treated by asymmetrical fronto-orbital remodeling (FOR) during the 1st year of life. The aim of this study was to elucidate to what extent orbital morphology is corrected by surgical treatment. The extent to which orbital morphology was corrected by surgical treatment was tested by analysis of differences in volume and shape between synostotic, nonsynostotic, and control orbits at two time points. In total, 147 orbits were analyzed from patient CT images obtained preoperatively (mean age 9.3 months), at follow-up (mean age 3.0 years), and in matched controls. Semiautomatic segmentation software was used to determine orbital volume. For analysis of orbital shape and asymmetry, geometrical models, signed distance maps, principal modes of variation, and three objective parameters (mean absolute distance, Hausdorff distance, and dice similarity coefficient) were generated by statistical shape modeling. Orbital volumes on both the synostotic and nonsynostotic sides were significantly smaller at follow-up than volumes in controls and significantly smaller both preoperatively and at follow-up than orbital volumes on the nonsynostotic side. Significant differences in shape were identified globally and locally, both preoperatively and at 3 years of age. Compared with controls, deviations were mostly found on the synostotic side at both time points. Asymmetry between synostotic and nonsynostotic sides was significantly decreased at follow-up, but not compared with the inherent asymmetry of controls. On a group level, the preoperative synostotic orbit was mainly expanded in the anterosuperior and anteroinferior regions and smallest on the temporal side. At follow-up, the mean synostotic orbit was still larger superiorly but also expanded in the anteroinferior temporal region. Overall, the morphology of nonsynostotic orbits was more similar to that of controls than to synostotic orbits. However, the individual variation in orbital shape was greatest for nonsynostotic orbits at follow-up. In this study, the authors presented what is, to their knowledge, the first objective automatic 3D bony evaluation of orbital shape in UCS, defining in greater detail than has been done previously how synostotic orbits differ from nonsynostotic and control orbits, and how orbital shape changes from 9.3 months of age preoperatively to 3 years of age at the postoperative follow-up. Despite surgical treatment, both local and global deviations in shape persist. These findings may have implications for future directions in the development of surgical treatment. Future studies connecting orbital morphology to ophthalmic disorders, aesthetics, and genetics could provide further insight to enable better outcomes in UCS.

The deviations of CD4 + T cells during peripheral blood and peritoneal fluid of endometriosis: a systematic review and meta-analysis.

To assess whether endometriosis (EMs) was related to systematic and/or local deviations of cluster of differentiation (CD)4 + T cells. Until November 2022, we enrolled a total of 1363 EMs and 1564 healthy women from 32 studies who met the inclusion criteria. After systematically retrieving the literature, we identified 1086 citations and 32 case-control studies were enrolled. Cumulative results suggested that there were insignificant deviations of CD4 + T cells during peripheral blood (PB) between EMs and healthy women (RR: -0.83, I2 = 99%, p = 0.65), also no statistically significant difference was found between mild and severe EMs (RR: 3.19, I2 = 94%, p = 0.19). We also found insignificant deviations of CD4 + /CD8 + during PB between EMs and healthy women (RR: 0.09, I2 = 99%, p = 0.39), and between mild and severe EMs (RR: -0.16, I2 = 99%, p = 0.29). The results might suggest that there was no significant correlation between EMs and systematic deviations of CD4 + T cells. When it came to local deviation during peritoneal fluid (PF), the polled results suggested that the frequency of CD4 + T cells during EMs was significantly lower than healthy women (RR: -5.38, I2 = 93%, p = 0.01), and the ratio of CD4 + /CD8 + during EMs was significantly lower than healthy women (RR: -0.13, I2 = 0%, p < 0.0001). However, there were insignificant deviations of CD4 + during PF between mild and severe EMs (RR: 1.65, I2 = 53%, p = 0.15), also there was an insignificant difference of CD4 + /CD8 + between mild and severe EMs (RR: -0.09, I2 = 14%, p = 0.19). EMs might be closely related to local deviations of CD4 + T cells. There was no obvious correlation between EMs and systematic deviations of CD4 + T cells, EMs might be closely related to local deviations of CD4 + T cells. Further study on the functional deviations and subpopulation distribution of CD4 + T cells is urgently needed.

Multimodal registration of ultrasound and MR images using weighted self-similarity structure vector

ProposeMultimodal registration of 2D Ultrasound (US) and 3D Magnetic Resonance (MR) for fusion navigation can improve the intraoperative detection accuracy of lesion. However, multimodal registration remains a challenge because of the poor US image quality. In the study, a weighted self-similarity structure vector (WSSV) is proposed to registrate multimodal images. MethodThe self-similarity structure vector utilizes the normalized distance of symmetrically located patches in the neighborhood to describe the local structure information. The texture weights are extracted using the local standard deviation to reduce the speckle interference in the US images. The multimodal similarity metric is constructed by combining a self-similarity structure vector with a texture weight map. ResultsExperiments were performed on US and MR images of the liver from 88 groups of data including 8 patients and 80 simulated samples. The average target registration error was reduced from 14.91 ± 3.86 mm to 4.95 ± 2.23 mm using the WSSV-based method. ConclusionsThe experimental results show that the WSSV-based registration method could robustly align the US and MR images of the liver. With further acceleration, the registration framework can be potentially applied in time-sensitive clinical settings, such as US-MR image registration in image-guided surgery.

Comparison of spatial interpolation techniques for innovative air quality monitoring systems

Different integration methods were tested to integrate data from a dynamic road network (ROM) in which pollution measurement sensors were mounted over delivery vans. Two methods were purposely developed, the isoelliptical expansion - ISOE - method accounting for the wind convective transport of pollutants and the modified isoelliptical expansion - MISOE - method in which, furthermore, local specific deviation of the pollution are estimated from historical sequences of pollution levels. The results obtained by these methods were compared with the well-known inverse distance weighted - IDW - method, which is only based on the distance from the interpolation sources. The comparison of the errors between the estimated values and the available measures reveals that the MISOE model provides more accurate estimated values with a low associated error. The ISOE model is more complicate than the IDW but provides better estimations in windy days. The maps of the local adjusting coefficients estimated month by months are able to identify critical areas to address in local environmental policy decisions.

Quantifying and analysing rock trait distributions of rocky fault scarps using deep learning

AbstractWe apply a deep learning model to segment and identify rock characteristics based on a Structure‐from‐Motion orthomap and digital elevation model of a rocky fault scarp in the Volcanic Tablelands, Eastern California, USA. By post‐processing the deep learning results, we build a semantic rock map and analyse the rock trait distributions. The resulting semantic map contains nearly 230 000 rocks with effective diameters ranging from 2 to 250 cm. Rock trait distributions provide a new perspective on rocky fault scarp development and extend past research on scarp geometry including slope, height and length. Heatmaps indicate rock size spatial distributions on the fault scarp and surrounding topographic flats. Median grain size changes perpendicular to the fault scarp trace, with the largest rocks on the downslope proximal to the scarp footwall. Correlation analyses illustrate the relationship between rock trait statistics and fault scarp geomorphology. Local fault scarp height correlates with median grain size ( = 0.6), the mean grain size of the largest rocks ( = 0.8) and the ratio of the number of small to large rocks ( = 0.4). The positive correlation ( = 0.8) between local fault scarp height and standard deviation of grain size suggests that rocks on a higher fault scarp are less well sorted. The correlation analysis between fault scarp height and rock orientation statistics supports a particle transportation model in which locally higher fault scarps have relatively more rocks with long axes parallel to fault scarp trace because rocks have a larger distance to roll and orient the long axes. Our work demonstrates a data‐driven approach to geomorphology based on rock trait distributions, promising a greater understanding of fault scarp formation and tectonic activity, as well as many other applications for which granulometry is an indicator of process.

Effects of municipal boundaries measured by combining urban scaling and spatial interaction.

Urban scaling, the superlinear increase of socio-economic measures with increasing population, is a well-researched phenomenon. This article is focused on socio-economic performance scaling, which could possibly be driven by increasing returns of the size and density of interaction networks. If this is indeed the case, we should also find that spatial barriers to interaction affect scaling and cause local performance deviations. Possible barring effects of municipal boundaries are important from the perspective of urban and regional governance. We test the hypothesis of barring effects by correlating municipal boundaries with the structure of commuter networks within a large densely urbanized region, the Randstad in The Netherlands. The measured impacts of these boundaries are correlated with local employment-scaling deviations. Applying spatially weighted modelling techniques, we find that municipal borders have significant effects on inter-municipal commuting and indicate these effects on the map. The results show particularly significant correlations along dividing lines between large urban agglomerations and rural communities. The southern part of the Randstad is more fragmented by such dividing lines than the northern part, which could partly explain the diverging economic development between the two parts.

Immune homeostasis modulation by hydrogel-guided delivery systems: a tool for accelerated bone regeneration.

Immune homeostasis is delicately mediated by the dynamic balance between effector immune cells and regulatory immune cells. Local deviations from immune homeostasis in the microenvironment of bone fractures, caused by an increased ratio of effector to regulatory cues, can lead to excessive inflammatory conditions and hinder bone regeneration. Therefore, achieving effective and localized immunomodulation of bone fractures is crucial for successful bone regeneration. Recent research has focused on developing localized and specific immunomodulatory strategies using local hydrogel-based delivery systems. In this review, we aim to emphasize the significant role of immune homeostasis in bone regeneration, explore local hydrogel-based delivery systems, discuss emerging trends in immunomodulation for enhancing bone regeneration, and address the limitations of current delivery strategies along with the challenges of clinical translation.

A new preoperative localization of pulmonary nodules guided by mixed reality: a pilot study of an animal model.

With the popularity of high-resolution computed tomography (HRCT), more and more pulmonary nodules are being discovered. Video-assisted thoracoscopic surgery (VATS) has become the first choice for surgical treatment of pulmonary nodules. The use of accurate preoperative localization is crucial for successful resection in VATS. At present, there are many kinds of preoperative localization methods, but there are certain disadvantages. This study aimed to evaluate the feasibility and safety of mixed reality (MR)-guided pulmonary nodules localization, which is a new method that can benefit patients to a greater extent. By constructing an animal model of pulmonary nodules localization, 28 cases of pulmonary nodules were located by MR-guided localization. We recorded the localization accuracy, localization time, insertion attempts, and incidence of complications related to localization under MR-guidance. All 28 nodules were successfully located: the deviation of MR-guided localization was 5.71±2.59 mm, localization time was 8.07±1.44 min, and insertion attempts was 1. A pneumothorax and localizer dislodgement occurred in 1 case, respectively. Since preoperative localization is critical for VATS resection of pulmonary nodules, we investigated a new localization method. As indicated by our study, MR-guided localization of pulmonary nodules is feasible and safe, which is worthy of further research and promotion. We have also registered corresponding clinical trials to further investigate and help to improve our understanding of this technique.

Interactive complex ontology matching with local and global similarity deviations

&lt;abstract&gt;&lt;p&gt;Ontology serves as a central technique in the semantic web to elucidate domain knowledge. The challenge of dealing with the heterogeneity introduced by diverse domain ontologies necessitates ontology matching, a process designed to identify semantically interconnected entities within these ontologies. This task is inherently complex due to the broad, diverse entities and the rich semantics inherent in vocabularies. To tackle this challenge, we bring forth a new interactive ontology matching method with local and global similarity deviations (IOM-LGSD) for ontology matching, which consists of three novel components. First, a local and global similarity deviation (LGSD) metrics are presented to measure the consistency of similarity measures (SMs) and single out the less consistent SMs for user validation. Second, we present a genetic algorithm (GA) based SM selector to evolve the SM subsets. Lastly, a problem-specific induced ordered weighting aggregating (IOWA) operator based SM aggregator is proposed to assess the quality of selected SMs. The experiment evaluates IOM-LGSD with the ontology alignment evaluation initiative (OAEI) Benchmark and three real-world sensor ontologies. The evaluation underscores the effectiveness of IOM-LGSD in efficiently identifying high-quality ontology alignments, which consistently outperforms comparative methods in terms of effectiveness and efficiency.&lt;/p&gt;&lt;/abstract&gt;

Bottom-Up Clustering and Merging Strategy for Irregular Curvature Aero-Blade Surface Extraction

Surface extraction plays a significant role in blade reconstruction and measurement, improving manufacturing quality and reducing costs. Boundary extraction and region growth are the most common solutions. However, these methods treat points as complete objects and extract surfaces aggressively. Since the model and geometric constraints of the surfaces are usually blurring, these methods will lead to low accuracy results and dramatically impact the effectiveness of existing methods in practice. This paper presents a novel bottom-up irregular curvature surface extracting method called SuCMIS segmenting blade surface points from an unstructured scanning point cloud. SuCMIS applies adaptive multiple clustering methods based on the local flatness and normal deviation minimum, which improves the robustness to noise and unpredicted systematic errors. Then the curvature-based cluster merging process runs to reconstruct the blade surface. Differ to existing model-based method, SuCMIS converts surface extraction into a bottom-up process with multiply surfaces clustering and merging. It does not rely on evaluating the accuracy of the model and geometric constraints, which overcomes the natural defects of existing methods significantly. Experiments demonstrate SuCMIS’s efficiency and robustness. Compared to baseline methods, SuCMIS improves extracting accuracy with acceptable execution time, especially for complicated and large point clouds, such as blade surfaces.

Noncovalent bonding assessment by pair distribution function.

Noncovalent interactions are essential in the formation and properties of a diverse range of materials. However, reliably identifying noncovalent interactions remains challenging using conventional methods such as X-ray diffraction, especially in nanocrystalline, poorly crystalline or amorphous materials which lack long-range lattice periodicity. Here, we demonstrate the accurate determination of deviations in the local structure and tilting of aromatic rings during the temperature-induced first order structural transition in the 1 : 1 adduct of 4,4'-bipyridinium squarate (BIPY:SQA) from the low temperature form HAZFAP01 to high temperature HAZFAP07 by X-ray pair distribution function. This work demonstrates how pair distribution function analyses can improve our understanding of local structural deviations resulting from noncovalent bonds and guide the development of novel functional materials.

Image detail enhancement of two-dimensional animation scene based on dual domain decomposition

In order to improve the performance of traditional image detail enhancement methods in distortion, real-time and detail information error, a new two-dimensional animation scene image detail enhancement method based on dual domain decomposition is proposed in this paper. Firstly, the two-dimensional animation scene image is divided into basic image domain and image detail domain by double domain decomposition. Then, the basic image domain is reconstructed and the image detail domain is denoised. Finally, the image detail enhancement is realised by fusing the results of information reconstruction and denoising. The simulation results show that the enhancement process of this method takes at least 11 minutes, and the maximum local standard deviation can reach 0.975, which is closer to 1.000, indicating that this method has the advantages of low distortion, high real-time performance and small detail information error.

Trueness of full-arch dental models obtained by digital and conventional impression techniques: an in vivo study

The aim of this study was to compare the trueness of complete- and partial-arch impressions obtained using conventional impression materials and intraoral scanners in vivo. Full-arch impressions were taken using polyether and polyvinylsiloxane. Gypsum casts were digitized using a laboratory scanner (IM, AF). Casts obtained from polyether impressions were also scanned using an industrial blue light scanner to construct 3D reference models. Intraoral scanning was performed using CEREC Omnicam (CO) and Trios 3 (TR). Surface matching software (Atos Professional) enabled to determine the mean deviations (mean distances) from the reference casts. Statistically significant discrepancies were calculated using the Wilcoxon signed-rank test. The mean distance for trueness ranged from 0.005 mm (TR) to 0.023 mm (IM) for the full arch, from 0.001 mm (CO) to 0.068 mm (IM) for the anterior segment, and from 0.019 mm (AF) to 0.042 mm (IM) for the posterior segment. Comparing the anterior vs. the posterior segment, significantly less deviations were observed for anterior with CO (p < 0.001) and TR (p < 0.001). Full-arch comparisons revealed significant differences between AF vs. IM (p = 0.014), IM vs. CO (p = 0.002), and IM vs. TR (p = 0.001). Full-arch trueness was comparable when using Affinis and the two intraoral scanners CEREC Omnicam and Trios 3. The digital impression devices yielded higher local deviations within the complete arch. Digital impressions of the complete arch are a suitable and reliable alternative to conventional impressions. However, they should be used with caution in the posterior region.Trial registration: Registration number at the German Clinical Trial Register (04.02.2022): DRKS00027988 (https://trialsearch.who.int/).

Triplets with a Twist: Ultrafast Intersystem Crossing in a Series of Electron Acceptor Materials Driven by Conformational Disorder.

Control over the populations of singlet and triplet excitons is key to organic semiconductor technologies. In different contexts, triplets can represent an energy loss pathway that must be managed (i.e., solar cells, light-emitting diodes, and lasers) or provide avenues to improve energy conversion (i.e., photon upconversion and multiplication systems). A key consideration in the interplay of singlet and triplet exciton populations in these systems is the rate of intersystem crossing (ISC). In this work, we design, measure, and model a series of new electron acceptor molecules and analyze them using a combination of ultrafast transient absorption and ultrafast broadband photoluminescence spectroscopies. We demonstrate that intramolecular triplet formation occurs within several hundred picoseconds in solution and is accelerated considerably in the solid state. Importantly, ISC occurs with sufficient rapidity to compete with charge formation in modern organic solar cells, implicating triplets in intrinsic exciton loss channels in addition to charge recombination. Density functional theory calculations reveal that ISC occurs in triplet excited states characterized by local deviations from orbital π-symmetry associated with rotationally flexible thiophene rings. In disordered films, structural distortions, therefore, result in significant increases in spin-orbit coupling, enabling rapid ISC. We demonstrate the generality of this proposal in an oligothiophene model system where ISC is symmetry-forbidden and show that conformational disorder introduced by the formation of a solvent glass accelerates ISC, outweighing the lower temperature and increased viscosity. This proposal sheds light on the factors responsible for facile ISC and provides a simple framework for molecular control over spin states.

Nearby galaxies in the LOFAR Two-metre Sky Survey

Context. Magnetic fields, which regulate stellar feedback and star formation in galaxies, are key to understanding galaxy evolution. Aims. We probe the origin of magnetic fields in late-type galaxies, measuring magnetic field strengths and exploring whether magnetic fields are only passive constituents of the interstellar medium or whether, being part of the local energy equilibrium, they are active constituents. Methods. We measure equipartition magnetic field strengths in 39 galaxies from the second data release of the LOFAR Two-metre Sky Survey (LoTSS-DR2) at 144 MHz with 6 arcsec angular resolution (0.1–0.7 kpc). For a subset of nine galaxies, we obtain atomic and molecular mass surface densities using H I and CO(2-1) data from the THINGS and HERACLES surveys, respectively. These data are at 13 arcsec angular resolution, which corresponds to 0.3–1.2 kpc at the distances of our galaxies. We measure kinetic energy densities using H I and CO velocity dispersions. Results. We find a mean magnetic field strength of 3.6–12.5 μG with a mean of 7.9 ± 2.0 μG across the full sample. The magnetic field strength has the tightest and steepest relation with the total gas surface density, with B ∝ ΣH I+H20.309 ± 0.006. The relations with the star-formation rate surface density and molecular gas surface density have significantly flatter slopes. After accounting for the influence of cosmic-ray transport, we find an even steeper relation of B ∝ ΣH I+H20.393 ± 0.009. Conclusions. These results suggest that the magnetic field is regulated by a B–ρ relation, which has its origin in the saturation of the small-scale dynamo. This is borne out by an agreement of kinetic and magnetic energy densities, although local deviations do exist, in particular in areas of high kinetic energy densities where the magnetic field is sub-dominant.

Odjeci Hrvatskoga proljeća u Virovitici 1971. i 1972.

Based on a historiographic and communication analysis of newspaper articles from Virovitički list and archival material of the Virovitica Municipal Assembly and District Committee of the League of Communists of Croatia in Virovitica, this paper investigates the echo of the national, cultural and political movement at the beginning of the 1970s. The authors interpret the political and social conditions in Virovitica during this period and analyze the echoes of the Croatian Spring in Virovitica’s politics, society, economy and culture. The tendencies that characterized the Croatian Spring in Virovitica did not differ from those in other areas. The central theme of the paper is the direct product of the reverberations of the Croatian Spring, which corresponded to the renewed functioning of the literary and cultural organization Matica hrvatska in 1971. The sanctions and penalties imposed against all supporters of the Croatian Spring are analyzed. The orders that come from the highest levels of government were readily accepted, both by the political authorities in Virovitica and by those who approved and edited the articles that appeared in the local newspaper. There was no question of the liberalization of local media, given that it “lasted” as long as the diversion of the local government, that is, the changes and deviations that occurred were caused by the actions of the authorities, republican and local, rather than emerging spontaneously. The methodology of the work and its coordination would be honed to perfection, and to an impartial observer it may have appeared that everything was in absolute harmony, but in fact it was a written and monotonous synchronization that occurred in conjunction with fear. The suppressed problems that reigned in Virovitica at the time, such as the impossibility of employment, the migration of its labour force abroad and even the defeatist policy compelled staff to leave municipal administration or refuse to even apply for job announcements all characterized Virovitica, and the political problems that occurred were less of a concern to the population than economic concerns. The paper presents a case study of the echoes of the largest Croatian national movement in the latter half of the 20th century in a small urban environment with the features of generic news reporting and unquestioning submission to the prevailing political ideology of that time and the consequences thereof.

Stabilizing Differential Interfacial Curvatures by Mismatched Molecular Geometries: Toward Polymers with Percolating 1 nm Channels of Gyroid Minimal Surfaces

Soft materials with self-assembled networks possess saddle-shaped interfaces with distributed negative Gaussian curvatures. The ability to stabilize such a geometry is critically important for various applications but can be challenging due to the possibly "deficient" packing of the building blocks. This nontrivial challenge has been manifested, for example, by the limited availability of cross-linkable bicontinuous cubic (Q) liquid crystals (LCs), which can be utilized to fabricate compelling polymers with networked nanochannels uniformly sized at ∼1 nm. Here, we devise a facile approach to stabilizing cross-linkable Q mesophases by leveraging the synergistic self-assembly from pairs of scalably synthesized polymerizable amphiphiles. Hybridization of the molecular geometries by mixing significantly increases the propensity of the local deviations in the interfacial curvature specifically required for Q assemblies. "Normal" (type 1) double gyroid LCs possessing 1 nm ionic channels conforming to minimal surfaces can be formulated by simultaneous hydration of the amphiphile mixtures, as opposed to the formation of hexagonal or lamellar mesophases exhibited by the single-amphiphile systems, respectively. Fixation of the bicontinuous network in polymers via radical polymerization has been efficaciously facilitated by the presence of the bifunctional polymerizable groups in one of the employed amphiphiles. High-fidelity lock-in of the ordered continuous 1 nm channels has been unambiguously confirmed by the observation of single-crystal-like diffraction patterns from synchrotron small-angle X-ray scattering and large-area periodicities by transmission electron microscopy. The produced polymeric materials exhibit the required mechanical integrity as well as chemical robustness in a variety of organic solvents that benefit their practical applications for selective transport of ions and molecules.

Determination of complex refractive index using maximum deviation angle through prism

Light-absorbing materials are widely used, and their optical properties are an important factor. Snell's law does not hold in materials that partially absorb light. Hence, the optical path in refraction is calculated from Maxwell's law. We used the optical path to obtain the deviation angle when a light passes through a prism made of light-absorbing material. The deviation angle has a local maximum. The deviation angle near the maximum is sensitive to the real and imaginary parts of the refractive index. The local maximum deviation angle and its incident angle are used to determine the complex index of refraction. This measurement has the same advantages as measuring the minimum deviation angle of a transparent prism. The detection is easy. Then, it is necessary to determine the complex refractive index from the measured maximum deviation angle and its incident angle. These two angles are plotted parametrically by varying the real part of the refractive index under a fixed imaginary part. The similar curves are drawn under the fixed real parts. Each curve has a fixed value for the real or imaginary part of the refractive index. Drawings of these many curves are made prior to measurement. Then we select the four curves that are closest to the measured local maximum deviation angle and its incident angle. Four fixed values attached to each of the four curves determine the complex index of refraction. The method in this paper can easily determine the complex refractive index and can be used for material identification.

Simultaneous Inference on the Korean Won-US Dollar Forward Premium Anomaly

The forward premium anomaly, which refers to the empirical failure of the uncovered interest parity (UIP), has been primarily examined by the forward premium regression of [Fama, E. (1984). Forward and spot exchange rates. Journal of Monetary Economics, 14(3), 319–338. https://doi.org/10.1016/0304-3932(84)90046-1]. Some studies apply the rolling-window regression to capture the time-varying coefficient on the forward premium, with difficulty in statistically testing the deviation of the coefficient from the UIP over time. We follow [Baillie, R., & Kim, K. (2015). Was it risk? Or was it fundamentals? Explaining excess currency returns with kernel smoothed regressions. Journal of Empirical Finance, 34, 99–111] to apply the simultaneous inference procedure to the Korean Won-US Dollar spot and forward exchange rates by estimating the time-varying coefficient from the kernel-smoothed local-linear regression and constructing the uniform confidence band to test the local deviation. We find that, while the UIP is not rejected from the baseline regression, the simultaneous inference shows that the deviation from the UIP is mainly observed during the early 2000s and 2010s. Time-variation of the forward premium coefficient tends to be significantly affected by economic uncertainties such as the interest rate, inflation, and stock return volatilities in Korea and US.