Real-time gait cycle parameter recognition using a wearable accelerometry system.

This paper presents the development of a wearable accelerometry system for real-time gait cycle parameter recognition. Using a tri-axial accelerometer, the wearable motion detector is a single waist-mounted device to measure trunk accelerations during walking. Several gait cycle parameters, including cadence, step regularity, stride regularity and step symmetry can be estimated in real-time by using autocorrelation procedure. For validation purposes, five Parkinson's disease (PD) patients and five young healthy adults were recruited in an experiment. The gait cycle parameters among the two subject groups of different mobility can be quantified and distinguished by the system. Practical considerations and limitations for implementing the autocorrelation procedure in such a real-time system are also discussed. This study can be extended to the future attempts in real-time detection of disabling gaits, such as festinating or freezing of gait in PD patients. Ambulatory rehabilitation, gait assessment and personal telecare for people with gait disorders are also possible applications.

Content of nutritional elements in sudangrass and ryegrass determined by ICP-AES.

The sudangrass (Sorghum sudanense) and ryegrass (Lolium multi florum L.) rotation is a new type of cropping system, which has developed rapidly in recent years in the south of China. The contents of nutritional elements for forage grass in the sudangrass and ryegrass rotation system were determined by ICP-AES. The results showed that there were abundant and essential nutritional elements for animals in sudangrass and ryegrass. The contents of P, K, Ca, Mg, S, Fe, B, Cu, Zn and Mn for sudangrass were 0.20% -0.29%, 1.94%-2.57%, 0.62%-0.97%, 0.39%-0.69%, 0.12%-0.18%, 108.35-180.12, 3.04-5.96, 6.17-10.02, 20.37-31.36 and 46.80-101.29 mg x kg(-1), respectively. The contents of P, K, Ca, Mg, S, Fe, B, Cu, Zn, Mn for ryegrass were 0.39%-0.70%, 3.77%-5.07%, 0.61%-0.84%, 0.28% -0.47%, 0.32%-0.41%, 291.65- 632.20, 2.13-3.23, 13.29-15.19, 30.73-42.98 and 92.08-156.04 mg x kg(-1), respectively, and there were differences between various periods in nutritional elements in the two forage grasses. The application of ICP-AES could reflect fast and efficiently the content of nutritional elements for forage grass as animals feed.

Usability evaluation of an instructional application based on Google Glass for mobile phone disassembly tasks.

This study aims at comparing a Google Glass-based instructional application with a printed manual in mobile phone disassembly tasks. Thirty participants (15 males and 15 females) were recruited to perform tasks via three types of instructional methods (Google Glass-based augmented reality, Google Glass-based video, and a printed manual). The objective measures of performance (task completion time, error counts), and the subjective measures (NASA-Task Load Index, system usability scale) were considered. Additionally, visual fatigue was assessed by critical flicker fusion frequency and near point accommodation. According to the findings, although the printed manual method produced better results regarding mental workload and system usability, the augmented reality method improved error reduction and efficiency. Furthermore, the participants indicated that the displayed animations were helpful in locating the exact work-pieces. The augmented reality method is believed to be a potential alternative to printed manuals in mobile disassembly tasks.

Evaluation of the Indonesian National Standard for elementary school furniture based on children's anthropometry.

In Indonesia, National Standardization Agency of Indonesia issued the Indonesian National Standard SNI 12-1015-1989 and SNI 12-1016-1989 to define the type of furniture dimensions that should be used by children in the elementary school level. This study aims to examine whether the current national standards for elementary school furniture dimensions issued by National Standardization Agency of Indonesia match the up-to-date Indonesian children's anthropometry. Two types of school furniture, small type (Type I, for grade 1-3) and large type (Type II, for grade 4-6), were evaluated in terms of seat height, seat depth, seat width and backrest height of a chair as well as the height and underneath height of a desk. 1146 students aged between 6 and 12 years old participated in the study. Seven anthropometric measurements were taken including stature, sitting shoulder height, sitting elbow height, popliteal height, buttock-popliteal length, knee height and hip breadth. Based on the standard school furniture dimensions and students' body dimensions, numbers of matches and mismatches between them were computed. Results indicated a substantial degree of mismatch between children's anthropometry and the standard dimensions of school furniture. The standard seat height was not appropriate for students among different grades with the mismatch percentage ranging from 63.4% to 96.7% for Type I and 72.7% to 99.0% for Type II. For desk height, the standard dimensions were not appropriate for students among different grades with the mismatch percentage ranging from 32.3% to 88.9% for Type I and 67.7% to 99.0% for Type II. Apparently, the current standards are out of date and need to be updated. Four different sizes of school furniture were hence proposed to accommodate the variation in students' anthropometry from Grade 1 to Grade 6. The proposed standard dimensions (PrS) of school furniture cover a slightly broader range of age and present a higher cumulative fit than the current standard dimensions (CrS). In addition, a better strategy for sizing can be also developed to fit chairs and desks to a larger number of students.

Ingress and egress motion strategies of elderly and young passengers for the rear seat of minivans with sliding doors.

This study investigates the motion strategies performed by elderly and young passengers while entering and exiting the rear seat of minivans with sliding doors. A minivan mock-up was constructed with four adjustable parameters to represent nine different conditions of vehicle geometry. Ten elderly male participants (66.8 ± 3.8 years old) and ten young male participants (31.5 ± 6.6 years old) were recruited. Each of them entered and exited the minivan mock-up for five times under each condition, and the motion data were acquired by the optical motion capture system. Based on the criteria derived from previous studies, all motions were automatically categorized into seven ingress motion strategies and seven egress motion strategies. Further, the differences among motion strategies are discussed in terms of vehicle factors and passenger factors, which provide clues for future studies.

The effect of arm posture on the scan-derived measurements.

Among various three-dimensional (3D) scanning anthropometric surveys, the inconsistent arm postures for scanning may lead to incompatible measurement results. Therefore, this study aims to investigate the effect of arm posture on the scan-derived measurements. The two arm postures in concern are the one with palms facing inward and the one with palms facing backward. The experimental results reveal that the two postures do not differ from each other in obtaining the scan-derived measurements for most body dimensions except for those related to the upper torso. Besides, the scan-derived measurements can be more precise between the two postures than the manual measurements. Further, it was found that being scanned with palms facing backward can contribute to the smaller difference between the scan-derived measurements and the manual measurements and the better image quality. Overall, the arm posture with palms facing backward is considered as the preferred posture for 3D whole body scanning.