自适应用户界面研究综述

自适应方式是人机交互领域的一项重要研究内容,也是解决目前系统、软件功能过剩问题的有效解决途径。本文介绍了目前应用在自适应用户界面的主要方式、自适应算法,以及自适应的属性,并讨论了自适应用户界面面临的问题和未来发展。     

Resurfacing of the humeral head: An analysis of the bone stock and osseous integration under the implant

Cementless‐surface‐replacement‐arthroplasty (CSRA) of the shoulder aims for functional joint restoration with minimal bone loss. Good clinical results have been reported, but due to the radiopaque metal shell no data is available on the structure, osseous integration, and bone stock under the implant. 14 hemi‐CSRAs (4 manufacturers) with two geometries (crown [n = 7]/ stem [n = 7] fixation) were retrieved from patients undergoing revision due to glenoidal erosion. Histological sections cutting through the implant centre and bone were analysed. Quantitative histomorphometry evaluated the bone‐implant‐contact and compared the bone‐area to native humeral retrievals (n = 7). The bone‐implant‐interface was further assessed by scanning‐electron‐microscopy (SEM) and energy‐dispersive‐x‐ray (EDX). Qualitative histology revealed a reduced and inhomogeneous bone stock. Obvious signs of stress shielding were observed with bone predominantly visible at the stem and implant rim. Quantitative histomorphometry confirmed the significantly reduced bone‐area (9.2 ± 3.9% [crown 9.9 ± 4.3%, stem 8.6 ± 3.6%]) compared to native humeri (21.2 ± 9.1%; p < 0.05). Bone‐implant‐contact was 20.5 ± 5.8% (crown 21.8 ± 6.2%, stem 19.2 ± 5.6%) which was confirmed by SEM and EDX. Altogether, CRSA shows satisfactory bone ingrowth at the interface suggesting sufficient primary stability to allow osseous integration. However, clear signs of stress shielding with an inhomogeneous and reduced bone stock were observed. The impact on the long‐term‐results is unclear requiring further investigation. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1382–1390, 2015.     

The Kv channel blocker 4-aminopyridine enhances Ag+ uptake: a scanning electrochemical microscopy study of single living cells

We report that silver ion (Ag⁺) uptake is enhanced by 4-aminopyridine (4-AP), a well known voltage-sensitive potassium ion channel (K_v) blocker. Both bacterial (Escherichia coli) and mammalian (3T3 fibroblast) cells were used as model systems. Ag⁺ uptake was monitored with a scanning electrochemical microscope with an amperometric Ag⁺ ion-selective electrode (Ag⁺-ISE) and the respiration rates of E. coli cells were measured by oxygen reduction at an ultramicroelectrode. The results showed that not only the amount but also the rate of silver uptake by the cells increased significantly when 4-AP was added to the solution. For fibroblasts, the Ag⁺ uptake rate was 4.8 × 10⁷ ions per cell per sec without 4-AP compared with 1.0 × 10⁸ ions per cell per sec with 0.2 mM 4-AP. For E. coli cells, the uptake rate was 1.5 × 10⁴ ions per cell per sec without 4-AP vs. 3.5 × 10⁴ ions per cell per sec with 0.5 mM 4-AP and 5.9 × 10⁴ ions per cell per sec with 1 mM 4-AP. Thus, 4-AP might be useful where silver is used as antimicrobial agent to speed its uptake.     

A clinical screening protocol for the RSVP Keyboard brain–computer interface

Purpose: To propose a screening protocol that identifies requisite sensory, motor, cognitive and communication skills for people with locked-in syndrome (PLIS) to use the RSVP Keyboard? brain–computer interface (BCI). Method: A multidisciplinary clinical team of seven individuals representing five disciplines identified requisite skills for the BCI RSVP Keyboard?. They chose questions and subtests from existing standardized instruments for auditory comprehension, reading and spelling, modified them to accommodate nonverbal response modalities, and developed novel tasks to screen visual perception, sustained visual attention and working memory. Questions were included about sensory skills, positioning, pain interference and medications. The result is a compilation of questions, adapted subtests and original tasks designed for this new BCI system. It was administered to 12 PLIS and 6 healthy controls. Results: Administration required 1?h or less. Yes/no choices and eye gaze were adequate response modes for PLIS. Healthy controls and 9 PLIS were 100% accurate on all tasks; 3 PLIS missed single items. Conclusions: The RSVP BCI screening protocol is a brief, repeatable technique for patients with different levels of LIS to identify the presence/absence of skills for BCI use. Widespread adoption of screening methods should be a clinical goal and will help standardize BCI implementation for research and intervention.

• Implications for Rehabilitation

• People with locked-in syndrome must have certain sensory, motor, cognitive and communication skills to successfully use a brain–computer interface (BCI) for communication.

• A screening profile would be useful in identifying potentially suitable candidates for BCI.

     

Application of BCI systems in neurorehabilitation: a scoping review

Purpose: To review various types of electroencephalographic activities of the brain and present an overview of brain–computer interface (BCI) systems’ history and their applications in rehabilitation. Methods: A scoping review of published English literature on BCI application in the field of rehabilitation was undertaken. IEEE Xplore, ScienceDirect, Google Scholar and Scopus databases were searched since inception up to August 2012. All experimental studies published in English and discussed complete cycle of the BCI process was included in the review. Results and discussion: In total, 90 articles met the inclusion criteria and were reviewed. Various approaches that improve the accuracy and performance of BCI systems were discussed. Based on BCI’s clinical application, reviewed articles were categorized into three groups: motion rehabilitation, speech rehabilitation and virtual reality control (VRC). Almost half of the reviewed papers (48%) concentrated on VRC. Speech rehabilitation and motion rehabilitation made up 33% and 19% of the reviewed papers, respectively. Among different types of electroencephalography signals, P300, steady state visual evoked potentials and motor imagery signals were the most common. Conclusions: This review discussed various applications of BCI in rehabilitation and showed how BCI can be used to improve the quality of life for people with neurological disabilities. It will develop and promote new models of communication and finally, will create an accurate, reliable, online communication between human brain and computer and reduces the negative effects of external stimuli on BCI performance.

• Implications for Rehabilitation

• The field of brain–computer interfaces (BCI) is rapidly advancing and it is expected to fulfill a critical role in rehabilitation of neurological disorders and in movement restoration in the forthcoming years.

• In the near future, BCI has notable potential to become a major tool used by people with disabilities to control locomotion and communicate with surrounding environment and, consequently, improve the quality of life for many affected persons.

• Electrical field recording at the scalp (i.e. electroencephalography) is the most likely method to be of practical value for clinical use as it is simple and non-invasive. However, some aspects need future improvements, such as the ability to separate close imagery signal (motion of extremities and phalanges that are close together).

     

Usability flaws of medication-related alerting functions: A systematic qualitative review

IntroductionMedication-related alerting functions may include usability flaws that limit their optimal use. A first step on the way to preventing usability flaws is to understand the characteristics of these usability flaws. This systematic qualitative review aims to analyze the type of usability flaws found in medication-related alerting functions.MethodPapers were searched via PubMed, Scopus and Ergonomics Abstracts databases, along with references lists. Paper selection, data extraction and data analysis was performed by two to three Human Factors experts. Meaningful semantic units representing instances of usability flaws were the main data extracted. They were analyzed through qualitative methods: categorization following general usability heuristics and through an inductive process for the flaws specific to medication-related alerting functions.Main resultsFrom the 6380 papers initially identified, 26 met all eligibility criteria. The analysis of the papers identified a total of 168 instances of usability flaws that could be classified into 13 categories of usability flaws representing either violations of general usability principles (i.e. they could be found in any system, e.g. guidance and workload issues) or infractions specific to medication-related alerting functions. The latter refer to issues of low signal-to-noise ratio, incomplete content of alerts, transparency, presentation mode and timing, missing alert features, tasks and control distribution.Main conclusionThe list of 168 instances of usability flaws of medication-related alerting functions provides a source of knowledge for checking the usability of medication-related alerting functions during their design and evaluation process and ultimately constructs evidence-based usability design principles for these functions.     

Molecular Dynamic Investigations on the Adhesion Behaviors of Asphalt Mastic–Aggregate Interface

The asphalt mastic–aggregate interface plays an essential role in determining the service performance of asphalt mixtures. The objective of this paper was to investigate the adhesion behaviors and mechanism between asphalt mastic and aggregate based on molecular dynamic (MD) simulations. First, the asphalt mastic model considering the actual mass ratio of filler to asphalt (F/A) condition was established and validated in terms of thermodynamic properties. Second, the molecular arrangement characteristics of polar components on the aggregate substrate were analyzed by radial distribution function (RDF), relative concentration (RC), and mean square displacement (MSD). Third, the interfacial adhesion ability between asphalt and aggregate was quantitively evaluated based on the work of adhesion. Finally, the coupling effect of moisture and temperature on interfacial adhesion behaviors was investigated to explore the adhesion failure characteristics of the asphalt–aggregate interface. The results demonstrate that the thermodynamic properties could be employed to validate the reliability of the asphalt mastic model. The self-aggregation degree of polar components in base asphalt could be significantly increased with the addition of silica particles, exhibiting a change of configuration from “parallel arrangement” into “stack distribution” due to the high polarity of silica particles. The polar components in asphalt mastic exhibit a more uniform distribution state and lower mobility capability than base asphalt owing to the adsorption effect of silica particles. Silica particles with amounts of residual charges could significantly increase the electrostatic energy of the asphalt mastic–aggregate interface, contributing to an improvement of the adhesion between asphalt mastic and aggregate. The increase of temperature enhances the work of adhesion of the asphalt mastic–aggregate interface, which is opposite to that of the base asphalt–aggregate interface. The asphalt mastic exhibits a greater sensitivity to interfacial moisture damage than base asphalt. The findings would provide insights into a better understanding on the micro adhesion mechanism of the asphalt mastic–aggregate interface.     

Interface Behavior and Interface Tensile Strength of a Hardened Concrete Mixture with a Coarse Aggregate for Additive Manufacturing

3D concrete printing technology (3DCP) is a relatively new technology that was first established in the 1990s. The main weakness of the technology is the interface strength between the extruded layers, which are deposited at different time intervals. Consequently, the interface strength is assumed to vary in relation to the time of concrete casting. The proposed experimental study investigated the behavior of a hardened concrete mixture containing coarse aggregates that were up to 8 mm in size, which is rather unusual for 3DCP technology. The resulting direct tensile strength at the layer interface was investigated for various time intervals of deposition from the initial mixing of concrete components. To better understand the material behavior at the layer interface area, computed tomography (CT) scanning was conducted, where the volumetric and area analysis enabled validation of the pore size and count distribution in accordance with the layer deposition process. The analyzed CT data related the macroscopic anisotropy and the resulting crack pattern to the temporal and spatial variability that is inherent to the additive manufacturing process at construction scales while providing additional insights into the porosity formation during the extrusion of the cementitious composite. The observed results contribute to previous investigations in this field by demonstrating the causal relationships, namely, how the interface strength development is determined by time, deposition process, and pore size distribution. Moreover, in regard to the printability of the proposed coarse aggregate mixture, the specific time interval is presented and its interplay with interface roughness and porosity is discussed.