Hard Floor Research Articles

Kinematic Analysis of VibroBot: A Soft, Hopping Robot with Stiffness- and Shape-Changing Abilities

Bouncing locomotion is used frequently in the animal kingdom for high speed movement over land. Animals also change their stiffness and shape to improve their locomotion ability. Both bouncing movement and stiffness- and shape-changing capabilities have been recently explored in robotics. In this paper a novel soft locomotion robot, VibroBot, is presented, capable of moving using a bouncing gait by inducing whole-body oscillations through rotation of an internal out-of-balance mass. VibroBot is capable of changing both its stiffness and shape to tackle challenging terrain and to overcome obstacles. When the robot is stiff, it is capable of high-frequency oscillatory locomotion suited to movement on hard surfaces, while in a compliant state it uses a lower-frequency higher-amplitude hopping gait suitable for travelling over soft or loose ground. Forward speeds of 8.5 cm/s (0.34 body lengths per second) on hard floor in VibroBot’s stiff state and 5 cm/s (0.2 body lengths per second) on sand in its compliant state were recorded. VibroBot can also selectively change its shape to climb obstacles with heights up to 3 cm (20% of the robot’s height in its stiff state), far greater than its hopping apex height (1 cm). Both simple bouncing gaits and stiffness- and shape-changing abilities show great promise for improving the locomotion abilities of soft robots.

Long-Lasting Changes in Muscle Twitch Force During Simulated Work While Standing or Walking

The aim of this study was to evaluate the long-lasting effects of prolonged standing work on a hard floor or floor mat and slow-pace walking on muscle twitch force (MTF) elicited by electrical stimulation. Prolonged standing work may alter lower-leg muscle function, which can be quantified by changes in the MTF amplitude and duration related to muscle fatigue. Ergonomic interventions have been proposed to mitigate fatigue and discomfort; however, their influences remain controversial. Ten men and eight women simulated standing work in 320-min experiments with three conditions: standing on a hard floor or an antifatigue mat and walking on a treadmill, each including three seated rest breaks. MTF in the gastrocnemius-soleus muscles was evaluated through changes in signal amplitude and duration. The significant decrease of MTF amplitude and an increase of duration after standing work on a hard floor and on a mat persisted beyond 1 hr postwork. During walking, significant MTF metrics changes appeared 30 min postwork. MTF amplitude decrease was not significant after the first 110 min in any of the conditions; however, MTF duration was significantly higher than baseline in the standing conditions. Similar long-lasting weakening of MTF was induced by standing on a hard floor and on an antifatigue mat. However, walking partially attenuated this phenomenon. Mostly static standing is likely to contribute to alterations of MTF in lower-leg muscles and potentially to musculoskeletal disorders regardless of the flooring characteristics. Occupational activities including slow-pace walking may reduce such deterioration in muscle function.

Housing and Social Environments of African (Loxodonta africana) and Asian (Elephas maximus) Elephants in North American Zoos.

We evaluated 255 African (Loxodonta africana) and Asian (Elephas maximus) elephants living in 68 North American zoos over one year to quantify housing and social variables. All parameters were quantified for the both the day and the night and comparisons were made across these time periods as well as by species and sex. To assess housing, we evaluated not only total exhibit size, but also individual animals’ experiences based on the time they spent in the unique environments into which the exhibits were subdivided. Variables developed to assess housing included measurements of area as a function of time (Total Space Experience), environment type (Indoor, Outdoor, In/Out Choice) and time spent on hard and soft flooring. Over the year, Total Space Experience values ranged from 1,273 square feet to 169,692 square feet, with Day values significantly greater than Night values (p<0.001). Elephants spent an average of 55.1% of their time outdoors, 28.9% indoors, and 16% in areas with a choice between being in or out. Time spent on hard flooring substrate ranged from 0% to 66.7%, with Night values significantly greater than Day (p<0.001). Social factors included number of animals functionally housed together (Social Experience) and social group characteristics such as time spent with juveniles and in mixed-sex groups. Overall Social Experience scores ranged from 1 to 11.2 and were significantly greater during the Day than at Night (p<0.001). There were few significant social or housing differences between African (N = 138) and Asian (N = 117) species or between males (N = 54) and females (N = 201). The most notable exception was Total Space Experience, with African and male elephants having larger Total Space Experience than Asian and female elephants, respectively (P-value<0.05). The housing and social variables evaluated herein have been used in a series of subsequent epidemiological analyses relating to various elephant welfare outcomes.

Correlation Between Running-reach Height And Agility K-test In Volleyball Players

Measurement of vertical jumping evaluates anaerobic power and has been a good predictor of performance in volleyball (Sawyer, at al., 2002). Vertical jump performance has been shown to be related to other performance factors such as speed, agility, and power (Barnes, at al., 2007). The correlation between a new Agility K-test (Cabell, at al., 2014) needed to be tested with an established vertical test. PURPOSE: To assess the relationship between running jump reach test and the Agility K-test. METHODS: Young male competitive volleyball players (n = 273, age 16.63 ± 1.51 years, height 185.53 ± 8.09 cm, mass 72.72 ± 8.41 kg) volunteered in the study. The subject stood about 5 meters from the base of the Vertec apparatus, and took 3 steps before leaping off both feet as high as possible, using the arms and legs to assist in projecting the body upwards. The subject attempted to take off at a point so that at the peak of the jump he was directly under the Vertec apparatus with his arm fully extended. The Agility K-test consisted of the subjects running at an indoor gym on hard wooden flooring between cones positioned in a “K” pattern at maximum speed. A contact switch for time measurement was placed on the top of each cone which subjects touched with the right or left hand. Pearson correlation coefficient test was used to correlate two dependent variables at alpha = .05. RESULTS: The young athletes achieved a time of 15.93 ± 0.48 s in the Agility K-test, and difference = reach - height = 126.67 ± 10.24 cm. A significant Pearson correlation coefficient for the difference and time was -.22 (p < .001). CONCLUSION: The results indicated a negative significant correlation between Agility K-test and running jump reach test with young-aged volleyball players. Other physiological factors relating to this correlation might include muscular strength, flexibility, and speed of the athletes. The nature of anaerobic power and agility is based on fast and explosive movements and varies in the studied age of the athletes.

The Influence of Pillow Material and Shape on Cervical Curvature Stability.

Objectives: This study intends to provide basic materials for selecting an appropriate type of pillow that will maintain the cervical spine to be in a neutral position during sleeping time. Methods/Statistical analysis: Twenty-eight male and female adults agreed to participate in this study. 30 minutes to measure the amount of change in the coordinates. Towel were spread on a hard and flat floor and the pillows were horizontally placed parallel to the x-axis of the three-dimensional motion analyzer with one of their corners positioned at the origin of coordinates. The participants lied on their pillow with their head located right in the middle of their pillow and for those who lied on a Memory foam Pillow (MP) or a functional pillow, they located their neck on the neck-supporting part of their pillow. The participants were put to the test for 30 minutes for each type of pillow and during the experiment, they were prohibited from talking or moving. One way repeated ANOVA is used to compare the change in the coordinate in time of the three pillows. Findings: The descriptive statistics that show the location of the pillows and the participants’ heads. Except for Lt 2 and Lt 3, all the markers showed a significant difference (p<.05). The descriptive statistics shows the height of the pillows and the participants’ heads. All the markers showed a significant difference (p<.05). The average amount of change in the location of the pillows is shown. The markers on the left side of the pillows showed no significant difference in the average amount of change in their location. Among the markers on the right side of the pillows, the markers showed a significant difference between Feather Pillow (FP) group and MP group and between MP group and The Functional Pillow (TFP) group. Among the markers attached on the participants’ face, there was a significant difference between FP group and MP group and between FP group and TFP group. The average amount of change in the location of the pillows is shown. Among the markers on the left side of the pillows, there was a significant difference in the average amount of change in the height of the pillows between FP group and MP group and between FP group and TFP group. Among the markers on the right side of the pillows, there was a significant difference in the average amount of change in the height of the pillows between FP group and MP group and between FP group and TFP group. Among the markers attached on the participants’ face, there was a significant difference between FP group and MP group, between MP group and TFP group and between FP group and TFP group. Application/Improvements: This study revealed that the material and type of pillow were related to SC and found out that using TFP, compared to the other two types of pillows, the height of the participants’ heads less significantly changed with the passage of time. Therefore, TFP can be recommended as an appropriate type of pillow with a proper level of SC for cervical spine .

Dynamic Mechanisms with Martingale Utilities

We study the dynamic mechanism design problem of a seller who repeatedly sells independent items to a buyer with private values. In this setting, the seller could potentially extract the entire buyer surplus by running efficient auctions and charging an upfront participation fee at the beginning of the horizon. In some markets, such as internet advertising, participation fees are not practical since buyers expect to inspect items before purchasing them. This motivates us to study the design of dynamic mechanisms under successively more stringent requirements that capture the implicit business constraints of these markets. We first consider a periodic individual rationality constraint, which limits the mechanism to charge at most the buyer's value in each period. While this prevents large upfront participation fees, the seller can still design mechanisms that spread a participation fee across the first few auctions. These mechanisms have the unappealing feature that they provide close-to-zero buyer utility in the first auctions in exchange for higher utility in future auctions. To address this problem, we introduce a martingale utility constraint, which imposes the requirement that from the perspective of the buyer, the next item's expected utility is equal to the present one's. Our main result is providing a dynamic auction satisfying martingale utility and periodic individual rationality whose profit loss with respect to first-best (full extraction of buyer surplus) is optimal up to polylogarithmic factors. The proposed mechanism is a dynamic two-tier auction with a hard floor and a soft floor that allocates the item whenever the buyer's bid is above the hard floor and charges the minimum of the bid and the soft floor.

就学前障がい児通所施設における運用実態からみた施設のあり方に関する研究

1. Background and Objective In recent years in Japan, the survival rate of newborns has been improving due to the advance in medical technology. At the same time, the number of children who are forced to live with some kind of disability has been increasing. This has led to the development of support facilities for disabled children. However, the design criterion for this type of facility determined by law only requires minimum placement of rooms and size. There have been many problems as this criterion does not correspond with actual operation of facilities. Also, the facilities were designed without understanding the characteristics of disabled children (e.g. hypersensitivity to sensory stimulus etc., ), which has been causing facility staff in many places to conduct improvements in the building. For the future, in order to improve such circumstance in developing a support facility for disabled children, it is necessary to consider a design criterion that reflects the actual operation. Therefore, this study aims at examining and suggesting considerations in designing a support facility for disabled children. 2. Method We extract problems at the time of operation from research of repair points and questionnaire survey in facilities for disabled children of Japan. In addition, in order to grasp the actual activity situation, a behavior observation was conducted, and the activity of staff, children and parents during the day were plotted at 5 minutes intervals on 2D diagram. in a facility located Kanto. From this, Characteristic situations in the facility from a viewpoint on activities and usage of furniture were extracted. With the method mentioned above, the considerations in designing a support facility for disabled children were examined. 3. Results As a result of surveys, we clarified following some points. 1) In the nursery room, blinder is put on doors and shelves to make the environment where disability children can concentrate on activities. 2) In the nursery room and hallway, In consideration for the safety of disability children, special keys are attached to doors so that children cannot go in and out without permission. 3) In the rooms such as the the nursery room and playroom, cushioning material was placed on the sash of doors/windows, corners of shelves, and pillars etc., for children's safety. 4) In welfare-oriented class (Wa), In order to make switching activities easy, the guidance training room is divided into 3 space with shelves and the children move between space for different activities. In addition, the characteristics such as inability to concentrate on activities because of surrounding objects are taken into account, thus the furniture or toys are prepared/removed for each activity to keep the guidance training room clear of things. 5) In medical-care-oriented class (Ka), since many children in this class cannot sit independently, most activities are done laying down on the floor. The parents also engage in most activities in a sitting position. Due to the hard floor, activities take place on a floor mattress. In addition, the supportive chairs cannot be stack for storage as they are custom made for each child's physical structure and level of disability. Since there is not enough space in the storage room, they are kept in the part of training room. 4. Conclusions In order to provide safety for children and create an environment to be able to concentrate, the factors mentioned in Table 5 should be taken into consideration when designing the facility. In view of this, along with considering the design criterion based on the actual operation, a designer must make an effort to communicate with facility managers and seek an understanding of disabled children.

ABSOLUTE VARIABILITY AND RELATIVE RELIABILITY OF THE TIMED STANDING BALANCE TEST IN CHILDREN WITH DOWN SYNDROME

Background: Reliability of an instrument or clinical test should be known in the field of rehabilitation medicine. But the reliability of most of clinical test to be used among pediatric population with disabilities is yet to be known. One among them is the timed standing balance test. Aim: To determine the minimal detectable change at 95% confidence (MDC 95 )for the static and dynamic standing balance test in children with Down syndrome (DS). Methods: A sample of nine (09) children with DS, aged between 8 and 17 years were recruited randomly from the recognized special school. Children with DS who were able to understand and obey simple commands were selected and noted their anthropometric measurements. Standing balance was assessed using timed unipedal stance on a hard floor for static and on foam with uniform density for dynamic balance. Standing balance was assessed thrice with an interval of minimum two (02) days in four conditions, Eyes Open Static (EOS), Eyes Closed Static (ECS), Eyes Open Dynamic (EOD) and Eyes Closed Dynamic (ECD) to estimate test retest reliability, Intraclass correlation coefficient (ICC). Then standard error of measure (SEM) and minimal detectable change (MDC 95 ) was calculated. Results: Test retest reliability in four conditions, EOS, ECS, EOD and ECD are ICC = 0.93, 0.91, 0.92 and 0.91 respectively while 1.27 s, 1.63 s, 0.58 s and 0.61 s are the MDC 95 required in four conditions. Conclusion: Absolute variability and relative reliability of the timed standing balance test in children with DS have been established.

A new metric for evaluating mid- and high-frequency impact noise

Impact isolation within multi-family dwellings is currently evaluated using the single number laboratory metric Impact Insulation Class (IIC) and associated field test metrics. There is wide acceptance that IIC does not adequately quantify low frequency impact noise such as thudding from footfalls which is prevalent in lightweight joist-framed construction. However, it is often assumed that mid- and high-frequency impact sources, such as heel clicks, dragging furniture, and dropping objects, are adequately characterized by IIC. Previous research by the authors have indicated that IIC does not adequately distinguish or rank-order between the acoustical performances of resilient matting located in the upper room of a floor ceiling assembly [LoVerde and Dong, J. Acoust. Soc. Am. 120, 3206 (2006); LoVerde and Dong, Proceedings of ICVS14 (2007)]. Many condominiums have regulations that require a minimum impact sound rating when replacing or installing hard surface finish flooring, and may require field testing to show compliance with the regulations. As expected, a field IIC metric like AIIC, NISR, or ISR is not a suitable descriptor for acoustical performance. A modified metric is defined that more accurately rank-orders the mid- and high-frequency impact noise performance of assemblies and is better suited for these performance requirements.

Spring jumpers vs power jumpers: ankle joint behavior in elite wushu athletes and implications for performance and injury risk

Wushu, better known as kungfu, is the modern athletic form of Chinese martial arts, and consists of performing a routine of martial arts movements as well as acrobatic jumps. Since those acrobatic jumps are performed on a hard floor, vertical jump height plays a major role in elite performance. Wushu coaches often mention two different types of athletes: spring jumpers and power jumpers. From this empirical point of view, spring jumpers seem to jump more easily. As in many sports, wushu jumps are performed with a run up followed by a stance phase with eccentric and concentric phases, often referred to as a ‘stretch-shortening cycle’ (SSC). Vertical jump height, in this case, is the result of three main components acting during the concentric phase: muscle fiber shortening, coordination between joints and recoil of elastic energy stored during the eccentric phase. Whereas the squat jump exercise (SJ) is used to evaluate the first component, the drop jump (DJ) can be used as a standard exercise to analyze the whole SSC. The overall ability of an athlete to benefit from a previous eccentric phase can be evaluated by pre-stretch augmentation (PSA), defined as the ratio of DJ and SJ performances (Kubo et al. 2007). Ankle behavior can be characterized by the evolution of joint torque, obtained with inverse dynamics, with respect to joint angle during the different phases of the support phase, with the slope being considered as overall joint stiffness. The aim of this study was to characterize spring and power jumpers in elite wushu athletes in terms of PSA, ankle laxity, and overall ankle stiffness during the concentric phase. The influence of the chosen jumping strategies on performance and injury risk will be also discussed.

Influence of Soft or Hard Floors before and after First Calving on Dairy Heifer Locomotion, Claw and Leg Health.

Simple SummaryIn this study the effect of different flooring systems on locomotion, claw conformation, loading, claw- and leg disorders was assessed in heifers from one year before to one year after calving. After calving, heifers kept on alleys covered with rubber flooring were found to develop less lameness, fewer claw disorders of the sole horn and fewer leg lesions than those kept on concrete alleys. Recruitment heifers reared on soft deep straw bedding had fewer sole horn lesions and more overgrown claws before calving, but were more prone to severe sole horn lesions after calving, than those reared in cubicles with hard concrete floors.Claw health, an important dairy cow welfare parameter, may be affected by early-life foot/leg stresses. To investigate this, groups of pregnant heifers were allocated to deep straw bedding (Soft) or cubicles (Hard), both with scraped concrete feeding alleys. After the grazing season, they were re-housed in cubicle systems, half on slatted concrete (Hard) and half on slatted rubber (Soft) alleys. Claw measurements, contact area and pressure distribution claw/flooring, claw disorders and leg lesions were recorded at the start and end of each housing season. Locomotion and leg lesions were also scored monthly after calving. Prevalence of sole haemorrhages was higher among pregnant heifers in cubicles than in deep straw. After calving, first-calvers on Hard floors had higher odds for lameness (OR = 3.6; p < 0.01), sole haemorrhages/ulcers (OR = 2.2; p < 0.05), white-line haemorrhages (OR = 2.8; p < 0.01) and leg lesions (OR = 2.6; p < 0.02) than those on Soft floors. Lowest prevalence and severity of sole and white-line haemorrhages (non-significant) in first-calvers was found in those on Soft floors and reared on Hard floors and the highest prevalence and severity on those on Hard floors reared on Soft floors. Soft flooring after calving is of most importance for healthy feet and legs.

Alterações radiográficas do aparato podotroclear de equinos da Polícia Militar de Minas Gerais sem sinais clínicos de doença do osso navicular

Os objetivos deste experimento foram identificar e associar alterações radiográficas do aparato podotoclear de equinos do Regimento de Cavalaria Alferes Tiradentes da Policia Militar do estado de Minas Gerais sem histórico e sinais clínicos de doença do osso navicular. Foi avaliado um total de 33 equinos, de ambos os sexos, com idade entre 10 e 20 anos. Os dígitos torácicos foram radiografados de forma padronizada nas projeções lateromedial (LM), dorsoproximal palmarodistal 65º (DPPD) e palmaroproximal palmarodistal (SK). A radiopacidade medular aumentada em projeção SK foi a principal alteração radiográfica detectada. Essa alteração foi associada a maior número de invaginações sinovais, a maior espessura de cortical em relação à medular em exposição SK e a maior relação corticomedular em exposição LM (P&lt;0,05). Esses achados indicam uma predisposição da população equina para desenvolver a síndrome do osso navicular, possivelmente associada ao trauma repetitivo promovido pelo constante trabalho em piso duro.

A decision support tool for communicating the environmental performance of products and organisations from the ceramic sector

This paper presents a tool designed to facilitate the communication of environmental information in the ceramic sector, both for companies and products. Specifically, the communication tool allows the environmental product declaration to be obtained for ceramic tiles in accordance with ISO 14025 and the environmental declaration of the organisation in accordance with the European Community Eco-Management and Audit Scheme (EMAS Register). Moreover, this tool makes it possible to verify compliance with the ecological criteria established by the European Eco-label programme for hard floor coverings (ceramic tiles) and, when they are not met, propose some best available techniques (BAT) to facilitate compliance with them. To do so, the tool is divided into four parts: (1) input data, where the user provides information related to the consumption of raw materials and resources, emissions into air, water and soil, solid waste, etc.; (2) database, including environmental indicators for different impact categories for the characteristics of the materials, processes and emissions of the ceramic sector; (3) reference documents, such as product category rules or different European regulations to guide the correct implementation of the environmental communication instruments included in the tool; and (4) output data in terms of the environmental declaration for the product and for the organisation, and verification of compliance with the European eco-label criteria and the proposal of BAT in the case of non-fulfilment, together with their environmental and economic consequences. The application of the tool is tested by a case study of ceramic tiles produced in an average Spanish organisation.

INCIDENCIA DEL DETERIORO PROGRESIVO DEL ARBOLADO URBANO EN EL VALLE DE ABURRÁ, COLOMBIA

&lt;span&gt;El arbolado urbano de los municipios del Valle de Aburrá, Colombia, está evidenciando deterioro y muerte por estrés hídrico y térmico, contaminación atmosférica, urbanización y ataques de plagas y enfermedades. Se realizó un muestreo de 11 710 individuos de 25 especies de árboles y palmas en el área metropolitana del Valle de Aburrá, con el propósito de registrar síntomas de deterioro progresivo (DP) como marchitez de ramas y secamiento descendente. Se estimó un modelo logit multifactorial que relaciona la incidencia del DP con características dasométricas de los individuos, el sitio de siembra y el número de afectaciones. Se encontraron 720 individuos con DP (incidencia de 6.1%). Los modelos logit tuvieron un ajuste satisfactorio a los datos y evidenciaron que existe una relación estadísticamente significativa entre la incidencia del deterioro de árboles y el diámetro del árbol, su ubicación (municipio), especie, sitio de siembra (zona verde, piso duro, alcorque) y presencia de otras afectaciones.&lt;/span&gt;

A life-cycle cost analysis for flooring materials for healthcare facilities

Objective: In this study, hard, resilient and soft flooring materials are compared using a building service life of 50 years, an established life span for healthcare facilities. The purpose of this study is to evaluate the life-cycle cost of flooring products and inform decision-makers about the long-term cost of ownership along with other key factors, such as safety, durability, and aesthetics.Methods: The protocol for executing an life-cycle cost analysis (LCCA) is defined by the National Institute of Standards and Technology (NIST), including defining the problem, identifying feasible alternatives, and establishing common assumptions and parameters, as well as acquiring financial information. Product information for the flooring materials that met inclusion criteria based on characteristics of the products consistent with use in healthcare facilities was acquired including maintenance, installation, warranty, and cost data. LCCA calculations recognize the time value of money and use discounting to project future value.Results: The results generated from the LCCA using present value to project future costs provide a useful tool for projecting costs over time for the purpose of planning operational and maintenance costs associated with the long-term investment of ownership. The findings suggest that soft flooring is more cost effective for initial purchase and installation, equipment assets, and maintenance over time of facilities.Conclusions: Cost is an important factor when considering flooring materials for healthcare facilities. Other factors to be considered are safety, durability and aesthetics, cleanliness, acoustics and sustainability to realize the overall return on investment. This study developed a tool for projecting costs of ownership for facility materials, in this case, flooring. The selection of flooring material has a significant impact on the cost of ownership over the life of the facility.

Between Sessions Reliability of the Agility K-test Among Young Athletes

PURPOSE: To assess the reliability of the Agility K-test. METHODS: Young recreational athletes (n = 119, age 14.00 ± 2.74 years, height 162.49 ± 11.89 cm, mass 50.84 ± 11.39 kg) volunteered in the study. The Agility K-test consisted of the subjects running at the indoor gym on hard wooden floor between cones positioned in a “K” pattern at maximum speed. The subjects started and ended running at the intersection of the “K” pattern. A contact switch for time measurement was placed on the top of each cone which subjects touched with the right or left hand. The subjects performed three repetitions with a 10-minute rest in between repetitions of the Agility K-test once a week over a period of two weeks, then two repetitions with a 10-minute rest the week after. The time of test execution was measured in seconds. The reliability was measured with the intraclass correlation coefficient. RESULTS: The young athletes achieved a time of 12.69 ± 1.13 s in the Agility K-test. The intraclass correlation coefficient of the K-test ranged from 0.83 to 0.99 across eight trials. CONCLUSION: The results indicated that the Agility K-test is a highly reliable test for use with young-aged subjects of recreational athletes.

The case for stepped-wedge studies: a trial of falls prevention

To do no harm is a fundamental tenet of clinical practice. Falls are harmful, especially for elderly people, because they can result in loss of confidence and permanent restriction of mobility. This is particularly the case in hospital settings, where hard flooring, sharp-edged furniture, and moveable bed furniture all increase the potential for serious injury. Patients are, by being in hospital, in a state of vulnerability. Disorientation, delirium, and weakness can increase the risk of falls. Fall rates in hospital rehabilitation units after individualised patient and staff education programmes: a pragmatic, stepped-wedge, cluster-randomised controlled trialIndividualised patient education programmes combined with training and feedback to staff added to usual care reduces the rates of falls and injurious falls in older patients in rehabilitation hospital-units. Full-Text PDF

Image-Based Navigation for the SnowEater Robot Using a Low-Resolution USB Camera

This paper reports on a navigation method for the snow-removal robot called SnowEater. The robot is designed to work autonomously within small areas (around 30 m2 or less) following line segment paths. The line segment paths are laid out so as much snow as possible can be cleared from an area. Navigation is accomplished by using an onboard low-resolution USB camera and a small marker located in the area to be cleared. Low-resolution cameras allow only limited localization and present significant errors. However, these errors can be overcome by using an efficient navigation algorithm to exploit the merits of these cameras. For stable robust autonomous snow removal using this limited information, the most reliable data are selected and the travel paths are controlled. The navigation paths are a set of radially arranged line segments emanating from a marker placed in the environment area to be cleared, in a place where it is not covered by snow. With this method, by using a low-resolution camera (640 × 480 pixels) and a small marker (100 × 100 mm), the robot covered the testing area following line segments. For a reference angle of 4.5° between line paths, the average results are: 4° for motion on hard floor and 4.8° for motion on compacted snow. The main contribution of this study is the design of a path-following control algorithm capable of absorbing the errors generated by a low-cost camera.

Should we change chest compression providers every 2 min when performing one-handed chest compressions?

Because the one-handed chest compression (OHCC) technique uses one hand, unlike the two-handed chest compression (THCC) technique, compression depth might be reduced more rapidly in OHCC than THCC. The present study was conducted to determine whether compression depth was affected within 2 min after the start of OHCC in a simulated in-hospital paediatric arrest model. Forty medical doctors performed continuous OHCC on a child manikin lying on a hard floor using a CPRmeter for 2 min. The hand used to perform the OHCC technique was randomised to the right or left hand. The mean compression depth (MCD) and the mean compression rate (MCR) were calculated at 30 s intervals using the Q-CPR review software. MCD values decreased significantly with time (0-30 s: 44.3 ± 4.1 mm, 30-60 s: 42.4 ± 4.9 mm, 60-90 s: 40.5 ± 5.8 mm, and 90-120 s: 38.7 ± 5.7 mm; P < 0.001). The MCR also tended to decrease with time (0-30 s: 119.3 ± 12.5/min, 30-60 s: 119.0 ± 13.1/min, 60-90 s: 117.9 ± 14.5/min, 90-120 s: 117.8 ± 14.9/min), and the differences were statistically significant between 30-60 s and 60-90 s (P = 0.037) and between 30-60 s and 90-120 s (P = 0.043). Compression depth was decreased significantly from 30 s onwards after starting the OHCC technique using a simulated paediatric arrest model. The results of the present study suggest that future strategies should be established to prevent a decrease in compression depth within 1 min during OHCC.

The effects of balance training and ankle training on the gait of elderly people who have fallen.

[Purpose] The aim of this study was to examine the effects of balance training and muscle training around the ankle joints on the gait of elderly people who have experienced a fall. [Subjects] Twenty-six elderly people with a risk of falling and a Berg Balance Scale score of 37 to 50 points who had experienced a fall in the last year were randomly and equally assigned to either a balance training group or an ankle training group. The balance training group received training on a hard floor, training while maintaining balance on a cushion ball in a standing position, and training while maintaining balance on an unstable platform in a standing position; the ankle training group received training to strengthen the muscles around the ankle joints and conducted stretch exercise for the muscles around the ankle joints. [Results] There were significant changes in gait velocity, step length, and stride length in the balance training group after the intervention; there were significant changes in gait velocity, cadence, step time, cycle time, step length, and stride length in the ankle training group after the intervention. In a between-group comparison, the gait velocity of the balance training group showed a significant improvement compared with the ankle training group. [Conclusion] Both balance training and ankle joint training are effective in enhancing the gait ability of elderly people with a risk of falling; in particular, balance training is effective in improving the gait velocity of elderly people who have experienced a fall compared with ankle joint training.