Test Assembly Research Articles

Computer Adaptive Multistage Testing: Practical Issues, Challenges and Principles

The purpose of many test in the educational and psychological measurement is to measure test takers’ latent trait scores from responses given to a set of items. Over the years, this has been done by traditional methods (paper and pencil tests). However, compared to other test administration models (e.g., adaptive testing), traditional methods are extensively criticized in terms of producing low measurement accuracy and long test length. Adaptive testing has been proposed to overcome these problems. There are two popular adaptive testing approaches. These are computerized adaptive testing (CAT) and computer adaptive multistage testing (ca-MST). The former is a well-known approach that has been predominantly used in this field. We believe that researchers and practitioners are fairly familiar with many aspects of CAT because it has more than a hundred years of history. However, the same thing is not true for the latter one. Since ca-MST is relatively new, many researchers are not familiar with features of it. The purpose of this study is to closely examine the characteristics of ca-MST, including its working principle, the adaptation procedure called the routing method, test assembly, and scoring, and provide an overview to researchers, with the aim of drawing researchers’ attention to ca-MST and encouraging them to contribute to the research in this area. The books, software and future work for ca-MST are also discussed.

Mechanical behaviour of pre-stressed spruce timber–timber 2.5-mm-step grooved connections under shearing tests

A smart shear connection system was tested in order to be used in manufactured elements of a lattice of wooden slats and a cross offset. This type of floor element can present advantages both in terms of weight and suitable insulating filler (Adalberth et al. 2001; Kawasaki and Kawai 2006; Kermani and Hairstans 2006; Dodoo et al. 2014). This connection is made to provide a substitute for a glue connection. The shear connection proposed is made by double-sided grooving timber interfaces to form a cross section. A specifically designed test assembly was constructed to measure and guarantee homogeneous contact pressure in interface test specimens. Shear test results are presented and compared in terms of capacity and stiffness with glue connections. The principal conclusions are as follows: the allowable shearing resistance of the grooved timber–timber joints can approximately reach the resistance of glued connections. The stiffness of the joints is improved by increasing the pre-stress applied for holding contact in the assembly. The grooved timber-to-timber joints exhibit non-linear behaviour which dominates the behaviour of the whole system. Therefore, the behaviour of a unit connection must be determined to obtain the mean load-carrying capacity and stiffness of a system with grooved connections.

Using Optimal Test Assembly Methods for Shortening Patient-Reported Outcome Measures: Development and Validation of the Cochin Hand Function Scale-6: A Scleroderma Patient-Centered Intervention Network Cohort Study.

To develop and validate a short form of the Cochin Hand Function Scale (CHFS), which measures hand disability, for use in systemic sclerosis, using objective criteria and reproducible techniques. Responses on the 18-item CHFS were obtained from English-speaking patients enrolled in the Scleroderma Patient-Centered Intervention Network Cohort. CHFS unidimensionality was verified using confirmatory factor analysis, and an item response theory model was fit to CHFS items. Optimal test assembly (OTA) methods identified a maximally precise short form for each possible form length between 1 and 17 items. The final short form selected was the form with the least number of items that maintained statistically equivalent convergent validity, compared to the full-length CHFS, with the Health Assessment Questionnaire (HAQ) disability index (DI) and the physical function domain of the 29-item Patient-Reported Outcomes Measurement Information System (PROMIS-29). There were 601 patients included. A 6-item short form of the CHFS (CHFS-6) was selected. The CHFS-6 had a Cronbach's alpha of 0.93. Correlations of the CHFS-6 summed score with HAQ DI (r = 0.79) and PROMIS-29 physical function (r = -0.54) were statistically equivalent to the CHFS (r = 0.81 and r = -0.56). The correlation with the full CHFS was high (r = 0.98). The OTA procedure generated a valid short form of the CHFS with minimal loss of information compared to the full-length form. The OTA method used was based on objective, prespecified criteria, but should be further studied for viability as a general procedure for shortening patient-reported outcome measures in health research.

Microstructural Indicators for Assessment of Effect of Prolonged and Intermittent Storage on Reliability of Lead-free Electronics

Electronic systems may be subjected to prolonged and intermittent periods of storage prior to deployment or usage. Prior studies have shown that the lead-free solder interconnects show measurable degradation in the mechanical properties even after the brief exposures to high temperature. In this paper, a method has been developed for determining the equivalent storage time to produce identical damage at a different temperature. Electronics subjected to accelerated tests often have a well-defined thermal profile for a specified period of time. Quantification of the thermal profile in field-deployed electronics may be often difficult because of the variance in the environment conditions and usage profile. There is a need for tools and techniques to quantify the damage in deployed systems in the absence of macroindicators of damage without the knowledge of prior stress history. The approach for mapping damage in the lead-free second-level interconnects between different thermal conditions is new. High-reliability applications, such as avionics and missile systems, may be often exposed to long periods of storage prior to deployment. The effect of storage at different temperature conditions can be mapped using the presented approach. A framework has been developed to investigate the system state and estimate the remaining useful life of the solder ball subjected to a variety of isothermal aging conditions, including 60 °C, 75 °C, and 125 °C for periods of time between 1 and 4 weeks. Data on damage precursors, including the rate of change in the normalized phase growth and the normalized IMC thickness, has been collected and analyzed to derive physics-based damage mapping relationships for aging. Mathematical relationships have been derived for the damage mapping to various thermal storage environments to facilitate determining an appropriate time–temperature combination to reach a particular level of damage state. Activation energy for the leading indicators of failure is also computed. Specific damage proxies examined include the phase-growth indicator and the intermetallic thickness. The viability of the approach has been demonstrated for the lead-free test assemblies subjected to multiple thermal aging at 60 °C, 75 °C, and 125 °C. Damage mapping relationships are derived from the data based on the two separate leading indicators.

Evaluation of the effect of temperature on mechanical properties and wear resistance of polyurethane elastomers

Polyurethane has excellent wear resistance and is an effective protective coating and liner against erosion caused by the impact of solid particles. However, the wear resistance of polyurethane is a function of working temperature due to the influence of heat on its mechanical properties. In this study, an erosion test assembly was designed and developed to evaluate the wear resistance of polyurethane elastomers at controlled temperatures. A cold gas dynamic spray system was used to conduct the erosion tests. The temperature of the exposed front surface of the target material was controlled by adjusting the gas temperature of the cold spray system, and the temperature on the unexposed surface of the samples was kept constant at a desired set-point by the use of a temperature controller, a thermocouple, and cartridge heaters. The transient temperature distribution within the samples was determined by the development of a three-dimensional finite element model. The velocity of the impacting particles was determined by a model based on the principles of supersonic fluid flow through a converging–diverging nozzle. Four polyurethane elastomers with Shore A hardness values of 55–85 were tested. The stress–strain behavior of the polyurethane elastomers was characterized at room and elevated temperatures by conducting tensile tests and cyclic loadings. The obtained results showed the substantial effect of testing temperature on erosion resistance of PU elastomers. Comparison of stress–strain behavior of the studied polyurethanes with their erosion resistance at controlled temperatures revealed that the residual strain as a result of plastic deformation and final elongation at break were the key parameters affecting the wear resistance of polyurethane elastomers. Evaluation of the surface morphology of the worn samples confirmed the importance of the residual strain on the erosion resistance of polyurethane elastomers.

Comment on Three-Element Item Selection Procedures for Multiple Forms Assembly: An Item Matching Approach.

A recent article in this journal addressed the choice between specialized heuristics and mixed-integer programming (MIP) solvers for automated test assembly. This reaction is to comment on the mischaracterization of the general nature of MIP solvers in this article, highlight the quite inefficient modeling of the test-assembly problems used in its empirical examples, and counter these examples by presenting the MIP solutions for a set of 35 real-world multiple-form assembly problems.

A Modified Hill-Climbing Algorithm for Knowledge Test Assembly Based on Classified Criteria

This paper presents our experience with the development of an automated knowledge test assembler. Items are selected from an item bank on the basis of precisely formulated formal criteria. The focus of our research was on the classification of criteria for item selection and on an algorithm that assembles a test using these criteria. The criteria are expressed through parameters of a heuristic function used to evaluate a test’s quality; they were derived from teaching experience and we consider them to be highly intuitive to teachers. Item selection is performed by searching a state space using modified hill-climbing. The proposed quality function is used to guide the search for the optimal test. The test assembler is implemented inside an in-house software system, developed for preparing and scoring of knowledge tests. We have shown a statistically significant improvement in the mean reliability of the tests assembled by our test assembler, compared to the tests assembled by a widely available state-of-the-art tool. The performance indicators of the test assembler were also measured and analyzed. The experiments’ results encourage both practical use of the assembler and further research.

A multistage adaptive test of fluid intelligence

Multistage adaptive testing has recently emerged as an alternative to the computerized adaptive test. The current study details a new multistage test to assess fluid intelligence. An item pool of progressive matrices with constructed response format was developed, and divided into six subtests. The subtests were applied to a sample of 724 college students and their psychometric properties were studied (i.e., reliability, dimensionality and validity evidence). The item pool was calibrated under the graded response model, and two multistage structures were developed, based on the automatic test assembly principles. Finally, the test information provided by each structure was compared in order to select the most appropriate one. The item pool showed adequate psychometric properties. From the two compared multistage structures, the simplest structure (i.e., routing test and two modules in the next stages) were more informative across the latent trait continuum and were therefore kept. Taken together, the results of the two studies support the application of the FIMT (Fluid Intelligence Multistage Test), a multistage test to assess fluid intelligence accurately and innovatively.

Fabrication and Testing of the 20 kA Binary Current Leads for the NHMFL Series-Connected Hybrid Magnet

A pair of binary vapor-cooled/high-temperature-superconducting current leads were fabricated at the National High Magnetic Field Laboratory (NHMFL) and tested at the High Field Magnet Laboratory (HFML) at the Radboud University Nijmegen. The leads supply current to the NHMFL series-connected hybrid magnet. Details of the fabrication are discussed, including that of the resistive and high-temperature-superconducting parts and the integration of the two sections. A test assembly was made, including the pair of current leads, a jumper made from NbTi cable-in-conduit, instrumentation, and mounting hardware. The test facility includes a liquid nitrogen supply vessel and a closed-loop supercritical helium supply system, to replicate the cooling used in the magnet assembly. Results from the testing of the leads to the full operating current, and under simulated loss-of-cooling conditions are presented.

Systematic Layout Planning and Balancing of Engine Production Processes for After Test and After Paint Assembly Lines

This paper is aimed at reducing the costs, maintaining the quality and designing the plant layout that is flexible to meet the customer demand. A number of stations in the after test assembly and after paint assembly are selected for capturing the production process requirements. Then, failure mode and effects analysis of after test assembly is carried out. Layout designs for the after test assembly and after paint assembly are developed using systematic layout planning and are validated using Spaghetti diagrams. With the improved layout, considerable reduction in the distance moved by the operator has resulted in 20 percent cost saving at 80 percent Takt time.

Experimental high gradient testing of a 17.1 GHz photonic band-gap accelerator structure

We report the design, fabrication, and high gradient testing of a 17.1 GHz photonic band-gap (PBG) accelerator structure. Photonic band-gap (PBG) structures are promising candidates for electron accelerators capable of high-gradient operation because they have the inherent damping of high order modes required to avoid beam breakup instabilities. The 17.1 GHz PBG structure tested was a single cell structure composed of a triangular array of round copper rods of radius 1.45 mm spaced by 8.05 mm. The test assembly consisted of the test PBG cell located between conventional (pillbox) input and output cells, with input power of up to 4 MW from a klystron supplied via a ${\mathrm{TM}}_{01}$ mode launcher. Breakdown at high gradient was observed by diagnostics including reflected power, downstream and upstream current monitors and visible light emission. The testing procedure was first benchmarked with a conventional disc-loaded waveguide structure, which reached a gradient of $87\text{ }\text{ }\mathrm{MV}/\mathrm{m}$ at a breakdown probability of $1.19\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}1}$ per pulse per meter. The PBG structure was tested with 100 ns pulses at gradient levels of less than $90\text{ }\text{ }\mathrm{MV}/\mathrm{m}$ in order to limit the surface temperature rise to 120 K. The PBG structure reached up to $89\text{ }\text{ }\mathrm{MV}/\mathrm{m}$ at a breakdown probability of $1.09\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}1}$ per pulse per meter. These test results show that a PBG structure can simultaneously operate at high gradients and low breakdown probability, while also providing wakefield damping.

High energy X-ray diffraction study of the relationship between the macroscopic mechanical properties and microstructure of irradiated HT-9 steel

Samples harvested from an HT-9 fuel test assembly (ACO-3) irradiated for six years in the Fast Flux Test Facility (FFTF) reaching 2–147 dpa at 382–504 °C were deformed in-situ while collecting high-energy X-ray diffraction data to monitor microstructure evolution. With the initiation of plastic deformation, all samples exhibited a clear load transfer from the ferrite matrix to carbide particulate. This behavior was confirmed by modeling of the control material. The evolution of dislocation density in the material as a result of deformation was characterized through full pattern line profile analysis. The dislocation densities increased substantially after deformation, the level of dislocation evolution observed was highly dependent upon the irradiation temperature of the sample. Differences in both the yield and hardening behavior between samples irradiated at higher and lower temperatures suggest the existence of a transition in tensile behavior at an irradiation temperature near 420 °C dividing regions of distinct damage effects.

An alternative method for measuring air-handling unit static pressure following ASHRAE Standard 37: Scenario 1—horizontal ducts with elbows (RP-1581)

ASHRAE Standard 37 (ASHRAE 2005) describes the air-side testing setup for the indoor side (i.e., air-handling unit) of a residential air-conditioning or heat pump system for energy performance testing. Furthermore, ASHRAE Standard 37 requires a straight downstream duct that forms a vertical test section of a specified length based on the air-handling unit outlet geometry for measuring the outlet static pressure. A potential problem is that adding this duct to the unit may result in an overall test apparatus height that exceeds psychrometric test room dimensions. One possible solution investigated in this project is to create a horizontal test section by the addition of an elbow placed after the unit. The air-handling unit outlet static pressure can then be measured in this horizontal test section, which has the same length requirements as that specified by ASHRAE Standard 37 for the vertical section. This horizontal duct orientation with an elbow is referred to as Scenario 1, while a second approach based on installing a passive resistive device at the air-handling unit outlet is referred to as Scenario 2, which is the subject of a second article. Experimental tests were performed on 2-, 3-, and 5-ton units, with a variety of elbow types and orientations located at the unit exit. Experiments were also performed on the same three units with vertical test sections as described in ASHRAE Standard 37 (i.e., baseline data). Comparisons of these test results showed that ASHRAE Standard 37 can be modified to reduce testing height restrictions by using a horizontal test section providing a right-angled elbow with double-thickness turning vanes and installed at the air-handling unit outlet in a specific orientation relative to the rotating blower. Specifically, this research found that the test section height downstream of the air-handling unit outlet could be reduced by 51% to 64% for the three different units, namely 2, 3, and 5 tons. Furthermore, with regard to the height of either the vertical baseline or horizontal Scenario 1 test assembly located in a psychrometric test room, this study showed that air-handling unit tests could be successfully performed in a 9-ft-high (2.7-m) room that would otherwise require a 12-ft-high (3.7-m) room following ASHRAE Standard 37 requirements.

An Automated Test Assembly Design for a Large-Scale Chinese Proficiency Test.

An Automated Test Assembly Design for a Large-Scale Chinese Proficiency Test.

Concept and implementation of an agent-based control architecture for a cyber-physical assembly system

Today’s production companies are challenged with: the assembly of different product variants with lot size of one on a single assembly line and the increase of product variants. The implementation of reconfigurable assembly systems with a modular design is a solution, which allows a flexible adaptation to different product variants. However, handling different assembly modules via specific communication protocols is limited by the current centralized control concepts. Therefore, this paper presents a concept for an agent-based control architecture. This concept uses coherent information starting from the planning process of the assembly system until the system is put into operation allowing a decentralized control. The decentralized agents in each station act as mediators between the modules and the assembly memory database enabling the product autonomous control throughout the assembly system. Moreover, the agent manages the data transfer for the modules with different specific syntaxes via respective communication protocols since a standardized communication protocol does not exist in industry. The concept is verified in a test assembly line for the production of small electronic components.

Automated top-down heuristic assembly of a classification multistage test

This paper discusses automated top-down heuristic assembly of multistage testing (MST). MST has gained increasing popularity in recent years. Automated test assembly (ATA) is one of the most important components for developing MST tests. In this study, we developed a top-down, heuristic design to assemble a classification MST test. Heuristic ATA methods have great application potential due to simplicity and feasibility. Top-down assembly is also a useful strategy for assembling short MST tests or migrating existing linear tests to MST. The full detail of the proposed assembly method is given in this paper. A simulation study was conducted to evaluate the assembly results under conditions crossed by the following five factors: 1) information target source; 2) assembly order among stages; 3) level of item overlap control; 4) number of stages; 5) stage length assignment. This paper could be used to guide practitioners and researchers on implementing this method in practice.

La diversidad funcional en la ecología de comunidades

Córdova-Tapia, F., Zambrano, L. 2015. Functional diversity in community ecology. Ecosistemas 24(3): 78-87. Doi.: 10.7818/ECOS.2015.24-3.10 With the aim of providing an overview of the concept of functional diversity and its application in the study of community ecology, this study examines the concepts of functional trait, functional niche and functional redundancy, and analyzes the classification of species into functional groups, the relationship between taxonomic diversity and functional diversity, and the usefulness of functional diversity to test assembly rules. Increasingly, empirical evidence on the study of the functional diversity there has the potential to clarify many of the patterns that have been observed in the communities and link them with the processes involved. However, one major challenge is to identify the functional traits that best describe the function of organisms in ecosystems are. Functional diversity has four separate components: functional richness, functional evenness, functional divergence and functional specialization. The relationship between functional richness and species richness is the key to understanding the effect of the number of species on ecosystem processes. Notwithstanding this importance, the relationship is still not clear in natural systems. In this sense, fish communities are an excellent model for analyzing communities in natural systems that incorporate multiple trophic levels. One of the most important applications of functional diversity in ecological communities is theory test assembly rules at different spatial and temporal scales.

Germinação de sementes de quinoa com diferentes períodos de armazenamento

This work aimed to evaluate the effect of different storage periods and the number of days to the germination of quinoa seeds. The seeds were obtained from plants cultivated under field conditions in the agricultural year of 2012/2013, in the municipality of Marechal Cândido Rondon, PR. The survey was conducted in the Seeds Technology Laboratory, at the State University of West Parana - UNIOESTE. The treatments consisted of the association between six storage periods (36, 85, 119, 146, 177 and 270 days) and eight days of germinated seeds counting, kept at 25 °C without photoperiod in four replicates of 100 seeds each. Germinating boxes (Gerbox) were used, containing germination paper on which the seeds were disposed. The quinoa seeds germination decreases with storage time increase, which also slows the germination. The count of the number of germinated seeds has to be performed on the eighth day after the assembly of the Standard Germination Test in quinoa. Normal 0 21 false false false PT-BR X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabela normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-fareast-language:EN-US;}

Approaching Roll-to-Roll Fluidic Self-Assembly: Relevant Parameters, Machine Design, and Applications

This paper presents the implementation of an automated roll-to-roll fluidic self-assembly system based on the surface tension driven self-assembly with applications in the field of macroelectronics. The reported system incorporates automated agitation, web motion, component dispensing, and recycling. The process enables the assembly and electrical connection of semiconductor dies/chips in a continuous and parallel fashion over wide area substrates. At present, the method achieves an assembly rate of 15000 chips per hour and an assembly yield exceeding 99%, testing assembly of standard square-shaped dies, 300-1000 μm size. Scaling the system to any desired throughput is possible due to the parallel manner of selfassembly. The identification and the modeling of the relationship between process parameters and forces have been studied and experimentally verified by testing the effect of the web angle, agitation on assembly, and detachment rates. As an application, we demonstrate the realization of a solid-state lighting module. This particular application requires the assembly of a conductive multilayer sandwich structure, which is achieved by combining the introduced assembly process with a novel lamination step.

An Evaluation of Different Statistical Targets for Assembling Parallel Forms in Item Response Theory.

Assembly of parallel forms is an important step in the test development process. Therefore, choosing a suitable theoretical framework to generate well-defined test specifications is critical. The performance of different statistical targets of test specifications using the test characteristic curve (TCC) and the test information function (TIF) was investigated. Test length, the number of test forms, and content specifications are considered as well. The TCC target results in forms that are parallel in difficulty, but not necessarily in terms of precision. Vice versa, test forms created using a TIF target are parallel in terms of precision, but not necessarily in terms of difficulty. As sometimes the focus is either on TIF or TCC, differences in either difficulty or precision can arise. Differences in difficulty can be mitigated by equating, but differences in precision cannot. In a series of simulations using a real item bank, the two-parameter logistic model, and mixed integer linear programming for automated test assembly, these differences were found to be quite substantial. When both TIF and TCC are combined into one target with manipulation to relative importance, these differences can be made to disappear.