Standard Artifacts Research Articles

Development of primary reference facilities and measurement comparison of standard artifacts for the bidirectional transmittance distribution function

To determine the bidirectional transmittance distribution function (BTDF) of diffusely transmitting materials, two new primary facilities have been developed at the Physikalisch-Technische Bundesanstalt (PTB) and Aalto University (Aalto). A detailed description of both facilities and the different approaches used are presented in this paper. The performance of both facilities is compared by determining the BTDF of two different diffuser types in both in-plane and out-of-plane bidirectional geometries at four different wavelengths in the visible spectral range. Due to delayed completion of PTB’s primary facility, the measured BTDF values are compared between Aalto’s primary facility and another PTB setup, whose measurement scales are successfully transferred to PTB’s primary facility by an internal comparison. A thorough analysis of the measurement uncertainty is presented, leading to a combined k = 1 standard uncertainty of 0.8%–1.2% for PTB’s primary facility and 1.3%–1.7% for Aalto’s primary facility. The BTDF results obtained agree well within their expanded k = 2 uncertainty. This indirect bilateral comparison shows that Aalto’s and PTB’s new facilities are suited as primary reference setups for the determination of the BTDF. These studies also reveal action points to improved measurement capabilities and for a reduction of the measurement uncertainty, depending on the type of diffuser under test.

Atom Probe Analysis of Nanoparticles Through Pick and Coat Sample Preparation.

The ability to analyze nanoparticles in the atom probe has often been limited by the complexity of the sample preparation. In this work, we present a method to lift–out single nanoparticles in the scanning electron microscope. First, nanoparticles are dispersed on a lacey carbon grid, then positioned on a sharp substrate tip and coated on all sides with a metallic matrix by physical vapor deposition. Compositional and structural insights are provided for spherical gold nanoparticles and a segregation of silver and copper in silver copper oxide nanorods is shown in 3D atom maps. Using the standard atom probe reconstruction algorithm, data quality is limited by typical standard reconstruction artifacts for heterogeneous specimens (trajectory aberrations) and the choice of suitable coatings for the particles. This approach can be applied to various unsupported free-standing nanoparticles, enables preselection of particles via correlative techniques, and reliably produces well-defined structured samples. The only prerequisite is that the nanoparticles must be large enough to be manipulated, which was done for sizes down to ~50 nm.

Evaluation of the Visibility and Artifacts of 11 Common Fiducial Markers for Image Guided Stereotactic Body Radiation Therapy in the Abdomen

PurposeThe purpose of this study was to quantitatively evaluate the visibility and artifacts of commercially available fiducial markers to optimize their selection for image guided stereotactic body radiation therapy. Methods and MaterialsFrom 6 different vendors, we selected 11 fiducials commonly used in image guided radiation therapy. The fiducials varied in material composition (e.g., gold, platinum, carbon), shape (e.g., cylindrical, notched/linear, coiled, ball-like, step), and size measured in terms of diameter (0.28-1.0 mm) and length (3.0-20.0 mm). Each fiducial was centered in 4-mm bolus within a 13-cm-thick water-equivalent phantom. Fiducials were imaged with the use of a simulation computed tomography (CT) scanner, a CT-on-rails system, and an onboard cone beam CT system. Acquisition parameters were set according to clinical protocols. Visibility was assessed in terms of contrast (Δ Hounsfield unit [HU]) and the Michelson visibility metric. Artifacts were quantified in terms of relative standard deviation and relative streak artifacts level (rSAL). Twelve radiation oncologists ranked each fiducial in terms of clinical usefulness. ResultsContrast and artifacts increased with fiducial size. For CT imaging, maximum contrast (2722 HU) and artifacts (rSAL = 2.69) occurred for the largest-diameter (0.75 mm) platinum fiducial. Minimum contrast (551 HU) and reduced artifacts (rSAL = 0.65) were observed for the smallest-diameter (0.28 mm) gold fiducial. Carbon produced the least severe artifacts (rSAL = 0.29). The survey indicated that physicians preferred gold fiducials with a 0.35- to 0.43-mm diameter, 5- to 10-mm length, and coiled or cylindrical shape that balanced contrast and artifacts. ConclusionsWe evaluated 11 different fiducials in terms of visibility and artifacts. The results of this study may assist radiation oncologists who seek to maximize contrast, minimize artifacts, or balance contrast versus artifacts by fiducial selection.

Clinical equivalence assessment of T2 synthesized pediatric brain magnetic resonance imaging

Background and purposeAutomated synthetic magnetic resonance imaging (MRI) provides qualitative, weighted image contrasts as well as quantitative information from one scan and is well-suited for various applications such as analysis of white matter disorders. However, the synthesized contrasts have been poorly evaluated in pediatric applications. The purpose of this study was to compare the image quality of synthetic T2 to conventional turbo spin-echo (TSE) T2 in pediatric brain MRI. Materials and methodsThis was a mono-center prospective study. Synthetic and conventional MRI acquisitions at 1.5 Tesla were performed for each patient during the same session using a prototype accelerated T2 mapping sequence package (TAsynthetic=3:07min, TAconventional=2:33min). Image sets were blindly and randomly analyzed by pediatric neuroradiologists. Global image quality, morphologic legibility of standard structures and artifacts were assessed using a 4-point Likert scale. Inter-observer kappa agreements were calculated. The capability of the synthesized contrasts and conventional TSE T2 to discern normal and pathologic cases was evaluated. ResultsSixty patients were included. The overall diagnostic quality of the synthesized contrasts was non-inferior to conventional imaging scale (P=0.06). There was no significant difference in the legibility of normal and pathological anatomic structures of synthetized and conventional TSE T2 (all P>0.05) as well as for artifacts except for phase encoding (P=0.008). Inter-observer agreement was good to almost perfect (kappa between 0.66 and 1). ConclusionsT2 synthesized contrasts, which also provides quantitative T2 information that could be useful, could be suggested as an equivalent technique in pediatric neuro-imaging, compared to conventional TSE T2.

A hammer is a hammer is a hammer

Cognitive Science Hammers are designed to strike other objects, such as a nail or a rivet. A hammer's use is independent of cultural norms or social agreements, in contrast to money, whose value and function as a medium of exchange very much relies on a common understanding, which can change when the consensus changes. Noyes et al. show that young children begin to grasp the difference between what the authors refer to as institutional (socially dependent) objects and standard artifacts, such as hammers and chairs, between the ages of 4 and 9 years. Cognition 10.1016/j.cognition.2017.09.008 (2017).

The emerging causal understanding of institutional objects

Institutional objects, such as money, drivers’ licenses, and borders, have functions because of their social roles rather than their immediate physical properties. These objects are causally different than standard artifacts (e.g. hammers, chairs, and cars), sharing more commonality with other social roles. Thus, they inform psychological theories of human-made objects as well as children’s emerging understanding of social reality. We examined whether children (N=180, ages 4–9) differentiate institutional objects from standard artifacts. Specifically, we examine whether children understand that mutual intentions (i.e., the intentions of a social collective) underlie the functional affordances of institutional objects in ways that they do not for standard artifacts. We find that young children assimilate institutional objects into their intuitive theories of standard artifacts; children begin to differentiate between the domains in the elementary school years.

Gold Fingers: 3D Targets for Evaluating Capacitive Readers

With capacitive fingerprint readers being increasingly used for access control as well as for smartphone unlock and payments, there is a growing interest among metrology agencies (e.g., the National Institute of Standards and Technology) to develop standard artifacts (targets) and procedures for repeatable evaluation of capacitive readers. We present our design and fabrication procedures to create conductive 3D targets (gold fingers) for capacitive readers. Wearable 3D targets with known feature markings (e.g., fingerprint ridge flow and ridge spacing) are first fabricated using a high-resolution 3D printer. A sputter coating process is subsequently used to deposit a thin layer (~300 nm) of conductive materials (titanium and gold) on 3D printed targets. The wearable gold finger targets are used to evaluate a PIV -certified single-finger capacitive reader as well as small-area capacitive readers embedded in smartphones and access control terminals. In additional, we show that a simple procedure to create 3D printed spoofs with conductive carbon coating is able to successfully spoof a PIV -certified single-finger capacitive reader as well as a capacitive reader embedded in an access control terminal.

Potential Stable Low-Permeation Rate Standard Based on Micro-machined Silicon.

Silicon wafers with micro-machined holes were evaluated for use as low-permeation-rate standard artifacts. Accuracy, stability, and reliability were assessed. Two independent experimental techniques for evaluating permeation were used: chilled mirror hygrometer and mass loss. The wafers exhibited a well-defined linear relationship between hole area and resultant water partial pressure for both techniques, although the mass loss curve exhibited a constant vertical offset from the hygrometer curve, attributed to water loss through the O-ring seal. In contrast to polymer permeation standards, Si wafers provided long-term reproducible permeation rates. However, they were also highly fragile, with most of them cracking during the course of the investigation.

E-Portfolios in Music and other Performing Arts Education: History through a Critique of Literature

The introduction and use of various forms of technology have been noted by historians of music as significant influences on ways in which music has developed. For example, George N. Heller notes that education in general and music in particular have felt impact of sound recording, film, television, videotape, computers, laser disk technology and a host of other innovations, while published materials and conferences on music regularly include research into applications and implications of types of electronic technology, as Peter R. Webster indicates. (1) This reflects technologizing of both in general and of music production and dissemination specifically. (2) In contrast to general computer-based technology, specific types of computer-based technology have strong relevance to learning and teaching of music and other performing arts, owing to their ability to store and present sound and filmed events, to represent multiple identities of performance educators (as creators, designers, performers, producers, researchers, teachers, technologists) through multimedia, and to provide sites of music creation, manipulation, and dissemination. As Renee Crawford puts it, the importance of technology in music has meant its necessary inclusion in teaching and (3) In discussion that follows, we focus on one such technological innovation, introduction and utilization of student e-portfolios in music and other performing arts education. We show history of their use, ways in which they have been and are currently implemented, and their influence on learning and teaching in these discipline areas. Since their introduction into university learning and teaching in early 1990s, e-portfolios have become standard artifacts through which students collate, archive, reflect on, and present outcomes of their studies. (4) For teaching staff they have numerous uses, including a means for assessment, an influence on curriculum design, a component of course content delivery, and an institutional capstone object in form of a final, summative object through which a student collates work completed in a degree program and thus demonstrates both knowledge gained and skills developed. The scope of their use extends from single task assignments to representation of student progression throughout degree programs. They have entered management systems of universities. (5) In some universities, e-portfolios have been mandated for both students and staff, and their use is widespread; in others, their use remains voluntary and piecemeal. (6) Research on e-portfolios is strongly represented from writers in Britain and United States but with regular contributions from researchers in Australia, Canada, Europe, and Scandinavia, all locations where educational technology is well established and economically supported and where its use is an expectation of systems. (7) Alongside generic research publications for and music and performing arts education, dedicated journals, professional associations, conferences, and websites have also examined e-portfolios. (8) In that timeframe, publication on issues surrounding use of e-portfolios has increased. Specifically in performing arts, a small amount of research in late 1990s by L. Castiglione, P. Moss, and Susan McGreevy-Nichols has been followed by widening exposure through discussions of their applications, roles, and significance. (9) At first, writers on e-portfolios discussed their usefulness alongside, or as replacements for, paper-based portfolios, which had been standard means of collating and demonstrating outcomes of student learning. As technology required for e-portfolio construction developed, especially with introduction of Web 2.0 and associated applications, a second stage of research tended to explain how e-portfolios were being used by students and components that were included. …

'Common...and Global:' Choosing Standard Artifacts and Processes for ERP Systems

Implementation of enterprise resource planning (ERP) systems has led to the motto, “Common ... and Global.” As a result, employing standard ERP systems has led to firms adopting common artifacts (e.g., vendor numbering systems) and processes (e.g., sales management) for global implementation. Although there are a number of important reasons for adoption of standards in an ERP system, unfortunately, adoption of a standard may have differential costs for divisions. What is optimal for one division or corporate is not optimal for each of the divisions.As a result, there is concern about how standard artifacts and processes are chosen for ERP systems. Is it possible to find standard artifacts and processes that are optimal for the corporation and each of the divisions? What choice process for ERP standards are rational? How can choice processes for selection of ERP standards be manipulated? This paper addresses these issues using analytic methods and information gathered from a number of ERP implementations.

Combining UML-MARTE and Preemptive Time Petri Nets: An Industrial Case Study

We present an approach for integration of formal methods within an industrial SW process, illustrating results obtained in a real scenario subject to Military Standard 498 (MIL-STD-498). On the one hand, the formal nucleus of preemptive Time Petri Nets (pTPNs) is used to support design and verification activities of the development process; on the other hand, the Unified Modeling Language (UML) profile for Modeling and Analysis of Real-Time and Embedded (MARTE) systems is adopted to manage the documentation process prescribed by MIL-STD-498. The two cores are integrated by providing guidance for translation of UML-MARTE specifications into equivalent pTPN models, with specific reference to concurrency control and synchronization mechanisms. This permits to attain a smooth transition from the standard artifacts of MIL-STD-498 to pTPN models and analyses, facilitating deployment of the formal core of pTPNs with a limited impact on the industrial practice. The experience proves practical feasibility and effectiveness of the approach, comprising a step towards industrial applicability of formal methods and practices.

The Virtual Close and Continuous Monitoring at Cisco

ABSTRACT This case analyzes the implementation of a virtual close and continuous monitoring capability at Cisco. Cisco was among the first firms to implement such a system capability. This case traces the development of that virtual close capability and monitoring system through technology changes, accounting process changes, changes in accounting policies, implementation of standard accounting artifacts, and reorganization of the accounting and finance functions, and examines some of the resulting payoffs. The case also examines some of the limitations of the system. In addition, the case examines how expectations of these capabilities may have resulted in a class action suit against Cisco. The case is appropriate for accounting information system and business courses that examine issues related to enterprise resource planning systems. The case also can be used to address issues such as reengineering the finance function and potential control needs in a virtual close environment.

Embedding domain-specific modelling languages in Maude specifications

We propose a formal approach for the definition and analysis of domain-specific modelling languages (dsml). The approach uses standard model-driven engineering artifacts for defining a language's syntax (using metamodels) and its operational semantics (using model transformations). We give formal meanings to these artifacts by translating them to the Maude language: metamodels and models are mapped to equational specifications, and model transformations are mapped to rewrite rules between such specifications, which are also expressible in Maude due to Maude's reflective capabilities. These mappings provide us, on the one hand, with abstract definitions of the mde concepts used for defining dsml, which naturally capture their intended meanings; and, on the other hand, with equivalent executable definitions, which can be directly used by Maude for formal verification. We also study a notion of operational semantics-preserving model transformations, which are model transformations between two dsml that ensure that each execution of a transformed instance is matched by an execution of the original instance. We propose a semi-decision procedure, implemented in Maude, for checking the semantics-preserving property. We also show how the procedure can be adapted for tracing finite executions of the transformed instance back to matching executions of the original one. The approach is illustrated on xspem, a language for describing the execution of activities constrained by time, precedence, and resource availability.

An imaging approach for a contactless monitoring of the conservation state of metallic works of art

An easy-to-use and cheap diagnostic tool based on digital photography and 2D-FFT imaging processing is described that can be used to monitor the corrosion process occurring over time on the surface of metallic works of art in indoor and outdoor environments and to assess the stability of the materials employed for restoration. The proposed solution has the advantage of not requiring standard lighting and artifacts manipulation, that are not easily achievable in real applications. The imaging algorithm is capable of highlighting the changes in the surface uniformity due to the corrosion process and can be used to put in evidence the beginning of dangerous localized corrosion phenomena onto the metallic surface. Although this technique does not allow a quantitative measurement of the corrosion rate, it has proved to be an effective approach to assess the stability of protective coatings. The proposed processing has been tested in laboratory to asses the stability of SiO2—like protective coatings deposited by PECVD on a set of silver reference alloys submitted to a tarnishing test in the presence of H2S vapors.

Slender Tactile Sensor for Contour and Roughness Measurements Within Deep and Narrow Holes

A tactile cantilever sensor is described which was designed for quality assurance of high-aspect ratio microcomponents, e.g., spray holes of diesel injector nozzles. It was constructed as an extremely slender silicon cantilever of 1.5-5 mm in length, 30-200 mum in width, and 25-50 mum in height comprising a silicon probing tip at its free end. Close to its clamping, a piezoresistive strain gauge was integrated for signal read-out. The novel sensor was designed to be operated at high scanning speeds offering a millimeter scanning range at a micrometer lateral resolution and a ten nanometers vertical resolution. Cross sensitivity versus temperature and ambient light referred to vertical tip deflection was below 10 nm during a tactile measurement, which was performed under typical tactile probing conditions, i.e., temperature and light intensity variations of 1 K and 0.1 mW/cm 2, respectively. In form and roughness measurements with calibrated standard artifacts as well as with narrow spray holes of advanced diesel injector nozzles, we demonstrated the potential of slender cantilever sensors for high-aspect-ratio micrometrology.

Progress on implementation of a reference measurement system based on a critical-dimension atomic force microscope

The National Institute of Standards and Technology (NIST) and SEMATECH are working to address traceability issues in semiconductor dimensional metrology. In semiconductor manufacturing, many of the measurements made in the fab are not traceable to the SI unit of length. This is because a greater emphasis is often placed on precision and tool matching than on accuracy. Furthermore, the fast pace of development in the industry makes it difficult to introduce suitable traceable standard artifacts in a timely manner. To address this issue, NIST and SEMATECH implemented a critical-dimension atomic-force-microscope-based reference measurement system (RMS). The system is calibrated for height, pitch, and width, and has traceability to the SI definition of length in all three axes. Because the RMS is expected to function at a higher level of performance than inline tools, the level of characterization and handling of uncertain sources is on a level usually seen in instruments at national measurement institutes. In this work, we discuss recent progress in reducing the uncertainty of the instrument as well as details of a newly implemented performance monitoring system. We also present an example of how the RMS concept can be used in a semiconductor manufacturing environment.

Accuracy of Nanoscale Pitch Standards Fabricated by Laser-Focused Atomic Deposition.

The pitch accuracy of a grating formed by laser-focused atomic deposition is evaluated from the point of view of fabricating nanoscale pitch standard artifacts. The average pitch obtained by the process, nominally half the laser wavelength, is simply traceable with small uncertainty to an atomic frequency and hence can be known with very high accuracy. An error budget is presented for a Cr on sapphire sample, showing that a combined standard uncertainty of 0.0049 nm, or a relative uncertainty of 2.3 × 10−5, is readily obtained, provided the substrate temperature does not change. Precision measurements of the diffraction of the 351.1 nm argon ion laser line from such an artifact are also presented. These yield an average pitch of (212.7777 ± 0.0069) nm, which agrees well with the expected value, as corrected for thermal contraction, of (212.7705 ± 0.0049) nm.

Analysis of 3-D surface waviness on standard artifacts by retroreflective metrology

Retroreflective metrology has been used to measure the 3-D surface waviness on standard artifacts. An optical configuration was constructed for the measurement, in which the grating image is produced by projection. The three-step algorithm of phase-shifting technology was applied to analyze the image. Two standard artifacts with 8.0- and 16.0-µm peak-to-peak wave amplitudes were tested. The experiments show that retroreflective metrology can successfully recover the contour and amplitude of the surface waviness on the standard artifacts. © 2000 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(00)02101-2]

Commercial helium permeation leak standards: Their properties and reliability

Standard leaks or leak artifacts are used extensively in industrial and research environments, typically for the calibration of helium leak detectors. The most commonly used leak is the helium permeation type, which uses a glass, quartz, or polymer barrier to restrict the flow of helium via diffusion. Physical leaks, on the other hand, use a physically restrictive element to limit the flow. This article will discuss the properties and reliability of helium permeation standard leaks, based on eight years of accumulated calibration data. Physical helium leaks will not be discussed since relatively few have been calibrated at the National Institute of Standards and Technology.

Continuous noninvasive real-time monitoring of stroke volume and cardiac output by thoracic electrical bioimpedance.

Thoracic electrical bioimpedance (TEB) is a noninvasive method for the estimation of left ventricular stroke volume (SV). Objections to TEB in the past have included systematic overestimation of SV and cardiac output in normals, poor correlation in absolute terms with standard cardiac output reference techniques, motion and ventilation artifacts which distorted recorded waveforms except when patients remained in apnea during measurements, and lack of a computer to yield rapid heat-to-beat quantitation of SV and cardiac output. The present study entails real-time, beat-to-beat cardiac output determinations using TEB and assessing its agreement via a digital computer against a reference standard, thermodilution. A correlation coefficient of 0.88 is reported with 85% of data points falling within 20% confidence limits on either side of the line of identity.