Optimization of a Polarization Nephelometer

The effect of parameters of a polarization nephelometer on its accuracy characteristic is analyzed. Errors in approximation of the actual scattering volume and actual optical beam by the elementary scattering volume and elementary beam are considered. A five-wave monochromatic source of radiation with the high spectral intensity of 0.15÷0.6 W is described. The design of polarization units is demonstrated.

The language of accurate and inaccurate eyewitnesses

Experimental psychologists have – for decades – espoused the unreliability of eyewitness identifications, but the advent of new statistical techniques such as confidence-accuracy characteristic analysis has revealed that eyewitness identifications are much more reliable than previously thought. When an eyewitness identifies the suspect with high confidence from an initial and properly-administered lineup, for example, that suspect is highly likely to be the person who originally committed the crime. The way confidence is collected in the laboratory – using a numeric rating scale – differs from the way confidence is collected in the real world – often by asking eyewitnesses to express their confidence in their own words. What is the best method for collecting an eyewitness’s level of confidence? To answer this question, we applied a novel machine-learning methodology to investigate the natural language of accurate and inaccurate eyewitnesses. This method revealed that verbal confidence statements provide much diagnostic information about the accuracy of identifications. Moreover, verbal confidence statements provide unique diagnostic information that is not otherwise captured by traditional indicators of identification accuracy such as numeric confidence ratings. However, the diagnostic value of a verbal confidence statement depends in part on the face recognition ability of the eyewitness: the natural language of strong face recognizers is more diagnostic than the natural language of weak face recognizers. These results are theoretically interesting, but from an applied perspective, this machine-learning methodology may prove useful to those in the criminal justice system that must evaluate eyewitnesses’ verbal confidence statements.

Confidence Can Be Used to Discriminate Between Accurate and Inaccurate Lie Decisions

There is a long-standing belief that confidence is not useful at discriminating between accurate and inaccurate deception decisions. Historically, this position made sense because people showed little ability to discriminate lie-tellers from truth-tellers. But, it is now widely accepted that, under certain conditions, people can discriminate between lie-tellers and truth-tellers. Nevertheless, belief that confidence does not discriminate between accurate and inaccurate responses persists. This belief is somewhat paradoxical because, to the extent that people can discriminate between lie-tellers and truth-tellers, signal detection theory naturally predicts a positive relationship between confidence and accuracy. In line with our signal-detection-based predictions, we show that, among decisions about whether someone is lying, those made with high confidence are more accurate than those made with low confidence. This important relationship has gone unnoticed in past work because of a reliance on inappropriate measures. Past research examining the confidence–accuracy relationship in deception research relied on correlating average confidence with proportion of correctly identified lies. These correlations provide information on whether more confident judges tend to be more accurate but remain silent on the arguably more important question of whether higher confidence decisions are more accurate than lower confidence decisions. We show that confidence–accuracy characteristic analyses are uniquely suited to measuring the confidence–accuracy relationship in deception research.

An Improved AMCL Algorithm Based on Laser Scanning Match in a Complex and Unstructured Environment

Adaptive Monte Carlo localization (AMCL) algorithm has a limited pose accuracy because of the nonconvexity of the laser sensor model, the complex and unstructured features of the working environment, the randomness of particle sampling, and the final pose selection problem. In this paper, an improved AMCL algorithm is proposed, aiming to build a laser radar-based robot localization system in a complex and unstructured environment, with a LIDAR point cloud scan-matching process after the particle score calculating process. The weighted mean pose of AMCL particle swarm is used as the initial pose of the scan matching process. The LIDAR point cloud is matched with the probability grid map from coarse to fine using the Gaussian-Newton method, which results in more accurate poses. Moreover, the scan-matching pose is added into the particle swarm as a high-weight particle. So the particle swarm after resampling will be more concentrated in the correct position. The particle filter and the scan-matching process form a closed loop, thus enhancing the localization accuracy of mobile robots. The experiment results demonstrate that the proposed improved AMCL algorithm is superior to the traditional AMCL algorithm in the complex and unstructured environment, by exploiting the high-accuracy characteristic of scan matching while inheriting the stability of AMCL.

US line-ups outperform UK line-ups

In the USA and the UK, many thousands of police suspects are identified by eyewitnesses every year. Unfortunately, many of those suspects are innocent, which becomes evident when they are exonerated by DNA testing, often after having been imprisoned for years. It is, therefore, imperative to use identification procedures that best enable eyewitnesses to discriminate innocent from guilty suspects. Although police investigators in both countries often administer line-up procedures, the details of how line-ups are presented are quite different and an important direct comparison has yet to be conducted. We investigated whether these two line-up procedures differ in terms of (i) discriminability (using receiver operating characteristic analysis) and (ii) reliability (using confidence–accuracy characteristic analysis). A total of 2249 participants watched a video of a crime and were later tested using either a six-person simultaneous photo line-up procedure (USA) or a nine-person sequential video line-up procedure (UK). US line-up procedure yielded significantly higher discriminability and significantly higher reliability. The results do not pinpoint the reason for the observed difference between the two procedures, but they do suggest that there is much room for improvement with the UK line-up.

Standardization of assay for cytokeratin-related tumor marker CYFRA21.1 in urine samples

The determination of tumor markers in urine samples has been proposed as an effective diagnostic tool in bladder cancer. The aim of the present investigation was to validate in urine samples the assay of the CYFRA21.1 cytokeratin-related marker, the serum concentrations of which showed promising diagnostic utility in patients with bladder cancer. First-voided urine samples were collected from patients with different malignancies. CYFRA21.1 was assayed with a commercially available enzyme immunoassay (Boehringer Mannheim). Different centrifugation patterns, the use of different buffers and nonionic detergents, and pH variations were evaluated. We demonstrated that: (a) cells and cell debris contain a large amount of CYFRA21.1 and must be eliminated by centrifugation; (b) storage at -20 degrees C causes amorphous precipitate, which may aspecifically bind CYFRA21.1; (c) the latter behavior may be prevented by diluting fresh urine samples with phosphate buffer with nonionic detergent added; (d) pH variations within the range 4.9-8.2 do not significantly affect CYFRA21.1 assay results. Provided that samples are diluted with buffer containing nonionic detergent, the CYFRA21.1 assay showed good precision and accuracy characteristic in urine samples. We therefore propose a standard protocol for the collection of urine samples for CYFRA21.1 assay. In a preliminary clinical evaluation, CYFRA21.1 concentrations in 16 patients with primary bladder cancer were higher than in healthy subjects. In the urine collected in the follow-up of patients treated for bladder cancer, CYFRA21.1 tended to be higher in relapsed patients than in those without evidence of disease. These preliminary data induced us to extend the clinical trial to establish the actual role of this assay in routine use.

The GLONASS System – An Overview

The principal characteristics of the GLONASS system, its current status and deployment outlook are considered. Comparison of the main characteristics of the GPS/GLONASS systems from the user's viewpoint is made. Proposals focused on the operations to be carried out to improve navigation determination accuracy for the users, provided with the combined equipment, are given. The data presented, received simultaneously on the user&s GLONASS equipment and a GP–500 GPS system, indicate that navigational determination accuracies of both systems are approximately equal. The key characteristics of 6–channel user facilities for civil aircraft and helicopters are presented. This equipment has been developed in the Institute of Space Device Engineering (ISDE) in accordance with a standard draft ARING on the combined system. The principal directions of the accuracy characteristic of the GLONASS system updating are considered. It is suggested to use the quantum–optical measurements on the Etalon satellite, launched into GLONASS satellite orbit, so that ephemeris information can be improved. The questions concerning supplying the system integrity and differential corrections information are discussed. It is proposed to combine the global system of integrity signal generation and transmission with differential corrections for regional systems. The version of the information frame developed in ISDE and intended for transmission of this information to users via geostationary satellites by means of signals similar to GPS/GLONASS, and without additional complication of user equipment, is presented here.