Determining targets for multi-stage adaptive tests using integer programming

This paper considers a multi-stage adaptive test (MST) where the testlets at each stage are determined prior to the administration. The assembly of a MST requires target information and target response functions for the MST design. The targets are chosen to create tests with accurate scoring and high utilization of items in an operational pool. Forcing all MSTs to have information and response function plots to be within an interval about the targets will yield parallel MSTs, in the sense that standardized paper-and-pencil tests are considered parallel. The objective of this paper is to present a method to determine targets for the MST design based on an item pool and an assumed distribution of examinee ability. The approach is applied to a Skills Readiness Inventory test designed to identify logical reasoning deficiencies of examinees. This method can be applied to obtain item response theory targets for a linear test as this is a special case of a MST.     

Multivariate rank statistics for testing randomness concerning some marginal distributions

In the present paper there is proposed a rank statistic for multivariate testing of randomness conceriing some marginal distributions. The asymptotic distribution of this statistic under hypothesis and “near” alternatives is treated.     

Analysis of Fissure-Filled Emeralds and Rubies by Diffuse Reflectance Fourier Transform Infrared Spectroscopy

ABSTRACT

Although diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) is mainly used for powdered solid samples, it was found to be highly effective for the analysis of certain gemstones. Small amounts of oils and resins used to fill cracks and fissures in substandard (included) emeralds and rubies could be detected. Because of their very low levels, these organic adulterants can be difficult to detect by measurement of the infrared transmittance spectrum. Rubies have a significantly larger “window-of-detection” for organic clarifying agents than do emeralds. In some cases the spectral information was sufficient to identify the oil or polymer resin. Emeralds that were treated over 20 years ago are still easily identified. The position of the emerald or ruby in the sample holder can affect the intensity of C-H and O-H stretching frequencies as well as those brands characteristic to the gemstones.     

食品塑料包装材料中化学物质的残留和分析

综述了近几年食品塑料材料中残留的化学物质和分析进展，内容包括聚乙烯、聚苯乙烯，聚氯乙烯、聚碳酸酯、三聚氰胺树脂及成型品。     

Testing nonlinear operators

We study testing of nonlinear operators; we want to test whether an implementation operator conforms to a specification operator. The problem is difficult, since there can be infinitely many possible inputs but we can only test finitely many of them. An implementation operator may perform well on the tested inputs but may be faulty on the untested inputs. In general, finite testing is inherently inconclusive. Consequently, we modify the problem in three different directions and obtain positive results: (1) We consider an infinite sequence of tests and prove that testing is decidable in the limit; (2) We relax the error criterion and show that finite testing is conclusive, however, the cost could be formidable; and (3) We tolerate faults on a negligible subset of inputs and develop a probabilistic testing algorithm with a significantly reduced cost. Our results indicate that test sets are universal; they only depend on the structure of the input set. In fact, they are provided by an net of the input set.This work was done while consulting at AT&T Bell Laboratories, and is partially supported by the National Science Foundation grant IRI-89-07215 and the Air Force Office of Scientific Research 91-0347.     

Conformity assessment and metrology: update on the state of affairs

A couple of years ago, ISO CASCO launched a major project of transforming all the existing ISO Guides on conformity assessment to a comprehensive series of ISO standards 17000 being now in various stages of development. As the concept of traceability underpinning all measurements has been a basic mission of metrology, a number of these standards have a direct bearing on metrology. The series is logically based on a definition standard, ISO 17000, giving, among others, a guidance which activities fall under conformity assessment. The fact that calibration does not, might have important consequences which must yet be assessed. A controversial discussion on some issues has been in progress concerning ISO 17011 on accreditation bodies which touches both on national metrology institutes (NMIs) with an accreditation function and on calibration labs at large. ISO 17040 on peer review could be used with an advantage to support mutual recognition arrangements among a limited number of bodies of a specialized expertise (e.g., CIPM MRA among NMIs under the Metre Convention). ISO 17025 has been the most important standard for the metrology community and has undergone a major overhaul taking on board the uncovered requirements from ISO 9001:2000. In general, the paper will give an update on the developments outlined above and discuss the consequences and further steps from the viewpoint of metrology.     

Up-to-date status of food irradiation

The last decade has witnessed significant advancement of the acceptance of food irradiation processing. At present 37 countries have approved one or more food items for human consumption and 25 countries have commercialized this process. More developing countries are showing keen interest to introduce irradiation processing in order to reduce post-harvest food losses, to increase export potentials and to ensure safety of food to their people. Although progress towards acceptance of food irradiation by the industry is slow, actual market trials have shown that once consumers have understood this technology, they are willing to buy irradiated foods.This paper deals with the latest developments in the field of food irradiation with particular reference to legislation, consumer acceptance, commercialization and potential application in developing countries. This paper also deals with the role played by the International Organizations, aimed at facilitating the acceptance of food irradiation.     

Introducing the concept of uncertainty of measurement in testing in association with the application of the standard ISO/IEC 17025

ISO/IEC 17025 requests laboratories to estimate the overall uncertainty associated with a test result. In many cases this means a new requirement to laboratories. It is essential to understand the importance of the knowledge of the uncertainty of measurements as well as the principle that not always the smallest possible uncertainty is needed, but fitness for purpose has to be achieved. The paper suggests a policy on the implementation of the concept of uncertainty and guidance on how to proceed, taking into account the present state of the art of understanding the problem.     

Fused deposition modeling-based additive manufacturing (3D printing): techniques for polymer material systems

While the developments of additive manufacturing (AM) techniques have been remarkable thus far, they are still significantly limited by the range of printable, functional material systems that meet the requirements of a broad range of industries; including the health care, manufacturing, packaging, aerospace, and automotive industries. Furthermore, with the rising demand for sustainable developments, this review broadly gives the reader a good overview of existing AM techniques; with more focus on the extrusion-based technologies (fused deposition modeling and direct ink writing) due to their scalability, cost efficiency and wider range of material processability. It then goes on to identify the innovative materials and recent research activities that may support the sustainable development of extrusion-based techniques for functional and multifunctional (4D printing) part and product fabrication.     

某机载惯导设备原位测试仪设计

针对某机载惯导设备在外场的测试需求,设计了以PC-104为显示、控制和数据处理核心,并扩展程控数字表、多通道矩阵板,构建了原位测试仪的硬件电路。根据系统的功能要求和硬件电路特性,利用LabWindows/CVI虚拟仪器平台编制了人机接口界面和测试程序,控制硬件电路对某惯导设备的静态电阻和在线电压进行测试,并接收、分析、处理惯导原位工作时输出的实时串行数据,完成对惯导设备的静态测试和动态性能监测,实现对某机载惯导设备原位测试过程的自动化和测试结果管理的智能化,提高了测试效率和测试精度。该仪器通过改变或控制测试仪器的类别,可实现对多路信号多种性能指标的测试。应用结果表明,该测试仪具有性能稳定、操作简便、应用领域广、通用性强等特点。