Vision based interface system for hands free control of an intelligent wheelchair

<p>Abstract</p> <p>Background</p> <p>Due to the shift of the age structure in today's populations, the necessities for developing the devices or technologies to support them have been increasing. Traditionally, the wheelchair, including powered and manual ones, is the most popular and important rehabilitation/assistive device for the disabled and the elderly. However, it is still highly restricted especially for severely disabled. As a solution to this, the Intelligent Wheelchairs (IWs) have received considerable attention as mobility aids. The purpose of this work is to develop the IW interface for providing more convenient and efficient interface to the people the disability in their limbs.</p> <p>Methods</p> <p>This paper proposes an intelligent wheelchair (IW) control system for the people with various disabilities. To facilitate a wide variety of user abilities, the proposed system involves the use of face-inclination and mouth-shape information, where the direction of an IW is determined by the inclination of the user's face, while proceeding and stopping are determined by the shapes of the user's mouth. Our system is composed of electric powered wheelchair, data acquisition board, ultrasonic/infra-red sensors, a PC camera, and vision system. Then the vision system to analyze user's gestures is performed by three stages: detector, recognizer, and converter. In the detector, the facial region of the intended user is first obtained using Adaboost, thereafter the mouth region is detected based on edge information. The extracted features are sent to the recognizer, which recognizes the face inclination and mouth shape using statistical analysis and <it>K</it>-means clustering, respectively. These recognition results are then delivered to the converter to control the wheelchair.</p> <p>Result & conclusion</p> <p>The advantages of the proposed system include 1) accurate recognition of user's intention with minimal user motion and 2) robustness to a cluttered background and the time-varying illumination. To prove these advantages, the proposed system was tested with 34 users in indoor and outdoor environments and the results were compared with those of other systems, then the results showed that the proposed system has superior performance to other systems in terms of speed and accuracy. Therefore, it is proved that proposed system provided a friendly and convenient interface to the severely disabled people.</p

Effective workload management in child welfare: Understanding the relationship between caseload and workload

A common assumption in public social service organizations is that workload may be positively associated with caseload. However, few empirical studies have examined what specific characteristics of caseload affect caseworkers' workloads in the child welfare system. This study attempts to address this gap by identifying specific individual and regional factors that influence both subjective and objective dimensions of workloads. Survey data were collected from 1,244 caseworkers at one public child welfare agency in a Midwestern state in the United States. The data indicated that both perceptions of unmanageable workloads and self‐reported overtime work were significantly higher when caseworkers had a greater number of cases than the state caseload standard for the investigations units and worked with at least two different types of cases simultaneously (e.g., working with both investigation and ongoing service cases). Additionally, sufficient staffing numbers to meet caseload demands at the regional level significantly decreased the odds ratio of having to do overtime work. The major findings suggest that the objective and subjective dimensions of workload vary by individual‐ and regional‐level variables. Practice implications are discussed for effective and efficient workload management in the public child welfare system

Intention to Use Long-Term Care Facilities: Differences between Korean Pre-elderly and Korean Baby-boomers

With the rapidly increasing number of older adults, dealing with long-term care (LTC) needs becomes an emerging issue in South Korea. This study aims to examine factors affecting the intention to use longtermcare facilities with two groups of young-old adults: (1) Korean pre-elderly (KPE) and (2) Korean babyboomers (KBB). Guided by Andersen's behavioral model of health service use and prior research, predisposing characters, enabling resources, need factors, availabilities of informal care and self-care activities were used as predictors. In the final analyses, 803 KPE and 966 KBB were included. The results of logistic regression analyses showed different findings in two groups. Age, education, spouse's physicalhealth, and self-care activities for relationship with family and friends are significantly associated with intention to use LTC facilities among KPE. However, income, physical health of respondents, and relationship satisfaction with children are significantly related to intention of use LTC facilities in the group of KBB. This study suggests different LTC needs between KPE and KBB. Health care professionals and policy makers need to consider such differences to provide quality LTC care for them

Role of Binder on Yield Strength of polycaprolactone/dimethylsulfone composites for bio-applications

Polycaprolactone (PCL) and dimethylsulfone (DMSO2) composites can tailor the properties of scaffold materials, allowing their use in bone tissue engineering. With an increase in DMSO2 content, the modulus of the material increases but not the yield strength. In order to increase yield strength, a binder was added. However, the optimization of the content and the mixing process of the binder were not optimized in the previous studies. In this study, gamma-methacryloxypropyltrimethoxysilane (A-174) was used as a binder to increase the strength of a composite. Four different mixing processes were employed based on the binder mixing sequence. The binders with content of 0, 0.4, 0.5, 0.7, and 1.5 phr were employed. The yield strengths of composites were investigated in terms of the binder mixing sequence and binder content. When the binder and DMSO2 particle fillers were premixed in the PCL matrix consisting of a DMSO2 filler and an A-174 binder system, the filler surface was coated smoothly and uniformly, and less agglomeration occurred. The yield strength of the composites with the appropriate mixing sequence was 36.71 % higher than that of the specimen without a binder, which was attributed to the improved adhesion between the matrix and fillers. Upon increasing the binder content, elongation and tearing of the matrix surface were observed in the cross-sections after yield tests; however, the weakening of mechanical anchoring was caused by excessive binder content, and filler debonding was observed on the surface. Because of the use of the A-174 silane binder at a concentration of 0.5 phr and the premixing of the binder and filler, the highest performance in terms of strength improvement of a PCL-20 wt % DMSO2 composite was achieved