Alignment System Research Articles

Integrated manufacturing of direct 3D-printed clear aligners

The inception of the laboratory work for a removable tooth moving appliance construction by sectioning the teeth from the malocclusion model to align them with wax and achieve minor dental correction has evolved into a state of digital planning and appliance manufacturing for a wide spectrum of malocclusion. The disruptive technology of directly printing clear aligners has drawn the clinician and researcher's interest in the orthodontic fraternity contemporarily. This workflow enables to the development of an in-house aligner system with complete control over desired aligner thickness, extent, and attachments; also technically resource-efficient with greater accuracy by excluding all the intermediate steps involved in the thermoforming method of manufacturing. This promising exploratory subject demands to be well-received with further research-based improvements. This article intends to summarize the digital orthodontic workflow and the literature evidence.

Improvements of the NIM-2 Joule Balance Since 2020

The joule balance, which relates the mechanical energy and the electrical energy, was proposed by National Institute of Metrology (NIM) to measure the Planck constant and realize the kilogram with the Planck constant based on the new definition of the kilogram. In 2019, the NIM-2 joule balance participated in the first key comparison of kilogram realizations (CCM.M-K8.2019) with a combined relative standard uncertainty of 4.5×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-8</sup> . After the first key comparison, a series of improvements on the mechanical, electrical, and the alignment systems have been carried out. To improve the accuracy of the electrical measurement, the periodical calibration of the digital voltmeter (DVM) with the Programmable Josephson Voltage System (PJVS) was also realized. The calibration period of the DVM was reduced from 5 days to 3.5 hours. With these improvements, the corresponding uncertainties were decreased significantly.

Multimedia Imaging System of Data Collection and Antenna Alignment for Unmanned Aerial Vehicles Based Internet of Things

Because network of sensors gives a more accurate representation of remotely sensed environments, a network of wirelessly connected sensors is essential. Data packets must be routed to the base station hop by hop, which causes conventional network data collecting to use a lot of power. Unmanned aerial vehicles (UAV) were employed for hovering over the detected environment and gather data to solve this issue. The paper also aims to provide an automatic alignment for UAV antennas for tracking by utilising computer vision technologies. A directional antenna with high gain is used by a ground station that can operate by a pan-tilt to point towards the low-gain omnidirectional antenna carried by the UAV. To center the UAV's antenna's image in the frame, the antenna is equipped with a camera, and a computer detects the video and controls the pan-tilt. The antennas are aligned if there are no more than a few pixels between the UAV image center and the image center. The proposed imaging system exhibits fast data collection, thus attaining a high packet delivery rate and the minimum use of energy. With the suggested antenna auto-alignment approach, the antennas can be accurately aligned with an angle error of under one. UAVs must take the smoothest and shortest pathways possible to accommodate their motion and time constraints. As a result, the Traveling Sales Problem (TSP) is utilized to determine the shortest route, and Bezier curves are then employed to turn paths into a flyable path.

Method for active spatial alignment and stabilization of laser beams in multi-beam systems

We propose a new method for the development of multi-beam systems for the spatial alignment and stability of beams based on the error separation technique. This method avoids alignment errors caused by coupling effect of piezoelectric devices, inaccurate correction calculations, and detection mode of the angular deviation. According to the results by external detectors, the error value of spatial alignment and the root mean square (RMS) of deviations under control during 1 h can be equivalent to approximately 0.87 and 1.06 nm at the sample plane under an oil immersion lens (focal length f=2 mm). The RMS of deviations is less than one-third of those currently reported for multi-beam systems; therefore, higher alignment and stability accuracy can be achieved with our proposed method.

High-accuracy laser spatial alignment and stabilization system with error separation technology

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Management Control Systems – Strategic Alignment Relations: A Study at Itaipu Binacional

Several papers have connected management controls to strategic commitment, innovation, and corporate governance, among other organizational outcomes. There are few studies that relate the levers of control framework proposed by Simons (1995) to strategic alignment. This paper aims to evaluate the relationships between Simons' strategic levers of control with the vertical strategic alignment at Itaipu Binacional. Data collected through a survey of 341 respondents and analysed through structural equation modelling by the Partial Least Squares (PLS) method revealed that the levers of control are associated, exerting a positive influence, with the strategic alignment, with diagnostic, beliefs, and interactive systems showing significant statistical associations.

Clear Aligner Therapy: Up to date review article.

The advantages of Clear Aligners Therapy (CAT) include the braces being virtually invisible, comfortable to wear, and removable for eating and brushing; that way, CAT can be used to treat a wide range of orthodontic issues. In 1999, the company Align Technology introduced the frst commercial clear aligner system called Invisalign. The Invisalign system was initially only available to orthodontists, but later became available to general dentists as well. The system quickly gained popularity among patients who were looking for a more discreet and comfortable alternative to traditional braces. In 2000, Align Technology received FDA clearance for the Invisalign system, which further increased its popularity. The biomechanics of clear aligners involve the use of custom-made tooth aligners that are specifcally shaped to guide teeth into desired positions. These aligners are typically made from flexible materials such as polyurethane or ethylene vinyl acetate and are adjusted to apply the necessary forces for tooth movement. Attachment devices, such as power ridges or buttons, are often used to enhance or assist in specifc tooth movements and for retention of the aligner. The use of attachments allows for the exertion of desired force on the teeth, which is crucial for the success of Clear Aligner Therapy. CAT should be used if patients are concerned about the esthetic appearances of their teeth-for example, actors and other individuals that rely on their appearances in public in a professional context-and if the misalignment is not severe, so that clear aligners can still work. One should not use CAT in cases of severe crowding or spacing issues that require extractions. If the patient has complex jaw discrepancies or skeletal issues or if teeth need to be moved extensively in multiple directions, CAT is likely not going to be strong enough. In conclusion, Clear Aligner Therapy is a safe, effective, and convenient orthodontic treatment option that offers patients a virtually invisible way to achieve a straighter, more beautiful smile. With continued advancements in technology and a growing body of research supporting its effectiveness, the future of Clear Aligner Therapy looks bright.

In Vivo Assessment of Shear Wave Propagation in Pennate Muscles Using an Automatic Ultrasound Probe Alignment System.

Goal: Skeletal muscle mechanics can be assessed in vivo using shear wave elastography. However, the impact of pennation angle on shear wave velocity (SWV) remains unclear. This study aims to quantify the effect by automatically aligning the ultrasound probe with muscle fiber orientation. Methods: We propose an automatic ultrasound probe alignment system and compare it to manual and no alignment. SWV of the gastrocnemius medialis muscle of ten volunteers was measured during rest and isometric contractions. Results: The SWV was different between the conditions (p = 0.008). The highest SWV was obtained during the automatic alignment and differences between the conditions were most pronounced during high-level contractions. The automatic system yielded more accurate alignment compared to a manual operator (p = 0.05). Conclusions: The present study indicates that pennation angle affects SWV, hence muscle fiber orientation must be considered to reliably interpret SWV. Using automatic alignment systems allows for more accurate alignment, improving the methodology of ultrasound elastography in skeletal muscles.

Development and algorithm research of optical alignment system for a high precision flip chip bonder

The predecessor of China Optics was China Optics and Applied Optics Digest, which was founded in 1985. At that time, it was the only retrieval journal in the field of optics in China. At the end of 2008, China Optics and Applied Optics Digest was renamed

HARDWARE ACCELERATION OF DNA READ ALIGNMENT PROGRAMS: CHALLENGES AND OPPORTUNITIES

The alignment or mapping of Deoxyribonucleic Acid (DNA) reads produced by the new massively parallel sequencing machines is a fundamental initial step in the DNA analysis process. DNA alignment consists of ordering millions of short nucleotide sequences called reads, using a previously sequenced genome as a reference, to reconstruct the genetic code of a species. Even with the efforts made in the development of new multi-stage alignment programs, based on sophisticated algorithms and new filtering heuristics, the execution times remain limiting for the development of various applications such as epigenetics and genomic medicine. This paper presents an overview of recent developments in the acceleration of DNA alignment programs, with special emphasis on those based on hardware, in particular Graphics Processing Units (GPUs), Field Programmable Gate Arrays (FPGAs), and Processing-in-Memory (PIM) devices. Unlike most of the works found in the literature, which review only the proposals that gradually emerged in some specific acceleration technology, this work analyzes the contemporary state of the subject in a more comprehensive way, covering from the conception of the problem, the modern sequencing technologies and the analysis of the structure of the new alignment programs, to the most innovative software and hardware acceleration techniques. The foregoing allows to clearly define, at the end of the paper, the trends, challenges and opportunities that still prevail in the field. We hope that this work will serve as a guide for the development of new and more sophisticated DNA alignment systems.

A Rapid Self-Alignment Strategy for a Launch Vehicle on an Offshore Launching Platform

To reduce the impact of offshore launching platform motion and swaying on the self-alignment accuracy of a launch vehicle, a rapid self-alignment strategy, which involves an optimal combination of anti-swaying coarse alignment (ASCA), backtracking navigation, and reverse Kalman filtering is proposed. During the entire alignment process, the data provided by the strapdown inertial navigation system (SINS) are stored and then applied to forward and backtrack self-alignment. This work elaborates the basic principles of coarse alignment and then analyzes the influence of ASCA time on alignment accuracy. An error model was built for the reverse fine alignment system. The coarse alignment was carried out based on the above work, then the state of the alignment system was retraced using the reverse inertial navigation solution and reverse Kalman filtering with the proposed strategy. A cycle-index control function was designed to approximate strict backtracking navigation. Finally, the attitude error was compensated for after the completion of the first and the last forward navigation. To demonstrate the effectiveness of the proposed strategy, numerical simulations were carried out in a scenario of launch vehicle motion and swaying. The proposed strategy can maximize the utilization of SINS data and hence improve the alignment accuracy and further reduce the alignment time. The results show that the fully autonomous alignment technology of the SINS can replace the complex optical aiming system and realize the determination of the initial attitude of a launch vehicle before launch.

EVALUATION OF THE NEW CONSTRUCTIVE-TECHNOLOGICAL SOLUTION OF THE FENCE STRUCTURE IN THE NON-REMOVABLE FORMWORK

The known constructive and technological solutions of enclosing constructions of buildings in fixed formwork with the use of qualitative, quantitative and general analysis are analyzed. Selected quantitative indicators, such as wall thickness, weight of 1 m2 of wall, heat transfer resistance, area of premises, cost, durability, tendency to shrinkage. Qualitative indicators were used: resistance to the sun, mold, fertilization and destruction, features of delivery of building materials. The method of multicriteria analysis is used to evaluate new structural and technological solutions of fencing structures and determine the most effective technologies. Categories of various constructive-technological decisions in a fixed timbering on the basis of economic consideration of modeling are considered. Such modern constructive-technological decisions of enclosing constructions in a fixed timbering are selected for comparison, as: expanded polystyrene blocks; blocks with wall alignment system; polystyrene concrete blocks; concrete blocks; blocks of cement-chip material; large panels made of expanded polystyrene; three-layer reinforced expanded polystyrene panels; cement particle boards; concrete slabs; frame-monolithic formwork with cement-chipboard cladding; frame-monolithic formwork with cladding of glass-magnesium plates and technology according to the patent UA 149402. The new design and technological solution, which has been developed and patented, is a combination of modern materials that are of great interest and demand to consumers, such as light steel thin-walled structures and expanded polystyrene concrete. The evaluation of technological solutions by quantitative criteria on a ten-point scale, where the minimum and maximum values are assigned points 1 and 10, respectively. Graphical modeling of the summary variants, which are equalized, is performed, and the corresponding diagrams are constructed.

An automatic alignment method for discharge arm of mobile crushing station based on binocular vision and fuzzy control

The mobile crushing station is one of the main equipment of the semi-continuous open-pit mining system. The discharge arm and the receiving equipment are manually aligned, which has the problems of long alignment time and low alignment accuracy, which affects the working efficiency of the mining system. According to the development and application of space rendezvous and docking technology at home and abroad, the advantages and disadvantages of different measurement methods are compared and analysed, and the method of applying binocular measurement technology to system positioning in the automatic alignment system of the discharge arm is determined. There are three movements in the mechanical part of the designed discharge arm alignment control system, including the rotary motion of the visual measurement mechanism and the horizontal rotation and telescopic motion of the discharge arm. According to the kinematic analysis and binocular vision measurement theory, the deviation model of the alignment control of the discharge arm is established. A binocular vision measurement and localization method based on the combination of stereo calibration and template matching is proposed, which achieves surprising measurement accuracy. An automatic alignment method of the discharge arm of the mobile crushing station is proposed based on the binocular vision and fuzzy control method. Its validity is verified by simulation and experiment. The strategy of motion decomposition is applied to the alignment system to avoid unnecessary motion of the discharge arm. The research results all show that the alignment method can achieve the angle deviation within ±0.5 degrees, the distance deviation within ±15 mm, and the test alignment time is about 5 minutes, which is better than other alignment control models; the alignment accuracy and the alignment time are improved by more than 50%. The method can control the discharge arm to complete the alignment task quickly and smoothly, which lays a foundation for the further automatic research of the discharge arm.

The Development and Challenges of Face Alignment: A survey

Finding the face key-points location or which is also called Face alignment has gotten a lot of interest in the last twenty years because of its wide range of applications in the major of automatic face analysis. Nonetheless, this task has proven an extremely challenging task in an unconstrained environment because of multiple confusing factors, such as occlusions, position, illumination, and expression. However, this task is still an open problem, even though researchers still developing a great many techniques to face the challenges of this problem, in this survey, a critical review of the current literature in the face alignment field had already been presented focusing on those methods tackling the total of this topic's challenges and difficulties under uncontrollable circumstances. Especially, the existing face alignment techniques have been categorized existing referring to more than the type of categorizing. Then represent a survey of the recent related works in face alignment and lastly, we discuss the general steps of the face alignment system.

Semantic alignment of ontologies meaningful categories with the generalization of descriptive structures

The presented work addresses the issue of semantic alignment of ontology components with a generalized structured corpus. The field of research refers to the sphere of determining the features of trust in artificial intelligence. An alignment method is proposed at the level of semantic components of the general alignment system. The method is a component of a broader alignment system and compares entities at the level of meaningful correspondence. Moreover, only the alignment entities’ descriptive content is considered within the proposed technique. Descriptive contents can be represented by variously named id and semantic relations. The method defines a fundamental ontol- ogy and a specific alignment structure. Semantic correspondence in the form of information scope is formed from the alignment structure. In this way, an entity is formed on the side of the alignment structure, which would correspond in the best meaningful way to the entity from the ontology in terms of meaningful descriptiveness. Meaningful descriptiveness is the filling of information scope. Information scopes are formed as a final form of generalization and can consist of entities, a set of entities, and their partial union. In turn, entities are a generalization of properties that are located at a lower level of the hierarchy and, in turn, are a combination of descriptors. Descriptors are a fundamental element of generalization that represent principal content. Descriptors can define atomic content within a knowledge base and represent only a particular aspect of the content. Thus, the element of meaningfulness is not self-sufficient and can manifest as separate meaningfulness in the form of a property, as a minimal representation of the meaningfulness of an alignment. Descriptors can also supplement the content at the level of information frameworks, entities, and properties. The essence of the alignment in the form of information scope cannot be represented as a descriptor or their combination. It happens because the descriptive descriptor does not represent the content in the completed form of the correspondence unit. The minimum structure of representation of information scope is in the form of properties. This form of organization of establishing the correspondence of the semantic level of alignment allows you to structure and formalize the information content for areas with a complex form of semantic mapping. The hierarchical representation of the generalization not only allows simplifying the formalization of semantic alignment but also enables the formation of information entities with the possibility of discretization of content at the level of descriptors. In turn, descriptors can expand meaningfulness at an arbitrary level of the generalization hierarchy. This provides quantization of informational content and flexibility of the alignment system with discretization at the level of descriptors. The proposed method is used to formalize the semantic alignment of ontology entities and areas of structured representation of information.

The vacuum chamber for the APPLE-X undulators at the European XFEL

Thanks to the installation of four APPLE X helical undulators, the SASE3 soft X-ray beamline at European XFEL will provide to the experimental stations the polarization control of the X-rays. The helical undulators are located downstream with respect to the already existing planar undulators. The design of the magnetic active parts and of the helical undulator support structure requires a new design of the vacuum chamber and its alignment system. This contribution describes the mechanical design, production process, UHV qualification process and alignment of the vacuum chamber.

A Customizable and Low-Cost Ultraviolet Exposure System for Photolithography.

For microfluidic device fabrication in the research, industry, and commercial areas, the curing and transfer of patterns on photoresist relies on ultraviolet (UV) light. Often, this step is performed by commercial mask aligner or UV lamp exposure systems; however, these machines are often expensive, large, and inaccessible. To find an alternative solution, we present an inexpensive, customizable, and lightweight UV exposure system that is user-friendly and readily available for a homemade cleanroom. We fabricated a portable UV exposure system that costs under $200. The wafer holder's adjustable height enabled for the selection of the appropriate curing distance, demonstrating our system's ability to be easily tailored for different applications. The high light uniformity across a 4" diameter wafer holder (light intensity error ~2.9%) was achieved by adding a light diffusing film to the apparatus. These values are comparable to the light uniformity across a 5" diameter wafer holder from a commercial mask aligner (ABM 3000HR Mask Aligner), that has a light intensity error of ~4.0%. We demonstrated the ability to perform photolithography with high quality by fabricating microfluidic devices and generating uniform microdroplets. We achieved comparable quality to the wafer patterns, microfluidic devices, and droplets made from the ABM 3000HR Mask Aligner.

The Principle and State-of-art Applications for CT Detector

Contemporarily, significant progress has been made in the development and application of image fusion technology in the field of diagnostic imaging. Image fusion is a fully automated image alignment and interpretation system that not only allows images with different characteristics to be displayed, interpreted, compared, and analyzed on the same platform, but also provides a fast and seamless pathway to clinical diagnosis and treatment. The purpose of this study was to explore the imaging theory, clinical advantages and limitations of CT. At the beginning of the study, the definition and development history of CT will be explained. Subsequently, in addition to imaging theory and key parameters, one can also understand the individual advantages and clinical application of CT. Afterwards, the limitations of CT will be mentioned, and the new technology of PET/CT will be introduced. As the most advanced medical imaging technology, PET/CT has improved the way of single PET and CT scanning, making them more widely used, making it the best combination of medical imaging and diagnostic technology. Overall, these results shed light on guiding further exploration of CT.

Predesign of a projector alignment system for structured light illumination systems

Structured light illumination systems can measure a target’s two-dimensional height profile. Recent advancements in computational power and algorithms have enabled the predesign of optical systems where all experimental variables are determined prior to use in the laboratory. We present a predesign process to align the projector of a custom-structured light illumination system. The predesign method uses the native optical design file to simulate the residual aberrations and can perform a trade space analysis to tailor the alignment variables to desired preferences. The presented method can predict the experimental focus position to 1.6 μm root mean square over a broad range of physical settings.

Linearized projector alignment system for structured light illumination systems using the quad target method

Structured light illumination (SLI) systems can measure a target’s two-dimensional height profile. High-quality imaging in SLI systems is typically dependent upon well-focused optical systems that can be difficult to achieve due to the nonlinear nature of defocus. We present the quad target method (QTM), a simple and fast alignment technique that linearizes defocus for SLI projectors. This linear response provides a clear zero crossing along the optical axis to minimize any focus ambiguity and maximize projector focus quality. QTM creates the linearization by sampling the field at two locations along the optical axis using a quad target, which is a diffuse target with two different heights in opposing quadrants. To maximize feedback speed, QTM can estimate the current focus position using only a single image by measuring the contrast of projected sinusoidal fringes on the quad target. QTM was tested using a commercial SLI system and compared with a published phase shifting reconstruction technique. The nonlinear defocus behavior was efficiently linearized as evidenced by focus estimation accuracies over a broad range of QTM variables.