OBJECTIVES: The aim of this study was to estimate musculo-skeletal symtoms of municipal sanitation workers and to evaluate working conditions of municipal sanitation workers to search for the factors related to musculo-skeletal symptoms. METHODS: We conducted a descriptive cross-sectional survey. The study subjects were comprised of 543 municipal sanitation workers in some divisions of Seoul and the Gyeonggi province. Musculo-skeletal analysis was done by using the modified criteria of NIOSH musuclo-skeletal symptoms, RULA and, REBA. Statistical analysis was done by using the chi-square test, multiple logistic regression analysis. RESULTS: 72.2% of the subjects complained musculo-skeletal symptoms (39.6% on the upperlimbs, 30.0% on the lumbar region, 27.4% on the legs). For the musculo-skeletal symptoms criteria (1~3), street cleaners complained of more musculo-skeletal symptoms than the solid waste collectors, after classifying the jobs of sanitation workers. On logistic regression analysis of the musculo-skeletal "symptoms criteria1" positive groups, age was related to the criteria positive (prevalence odds ratio=1.018, 95% CI: 0.993-1.046). The worktime was significantly related to 'criteria positive 1 and, 2' (prevalence odds ratio=2.165 (95% CI: 1.156-4.131), 2.187 times (95% CI: 1.071-4.651)). The RULA score, the subtotal A score of RULA, the REBA score and , the total A REBA score of the upperlimbs of solid waste collectors were higher than those of the street cleaners. CONCLUSIONS: In spite of the lower ergonomic evaluation score of the street cleaner, the street cleaners complained of more musculo-skeletal symptoms than did the solid waste collectors due to more frequent repetitive motions, a longer work time (over 10 hours) etc. It is suggested that the sanitation workers need to use the proper methods to avoid musculo-skeletal disease.
Cross-Sectional Studies ; Human Engineering ; Humans ; Logistic Models ; Lumbosacral Region ; National Institute for Occupational Safety and Health (U.S.) ; Sanitation ; Solid Waste ; Task Performance and Analysis ; Upper Extremity

Recently, traditional impression has been rapidly replaced by digital impression using intraoral scanning. There are more than 7 types of intraoral scanners available in the dental market. It is difficult to make effective strategic choices due to a lack of standards and guidelines for optimal intraoral scanning devices. So far, little has been reported about evaluating the ergonomic aspect of these scanners. This literature review compares current intraoral scanning systems based on different types of handles and suggests the most comfortable, user-friendly intraoral scanners from an ergonomic standpoint.
Human Engineering

In order to study event-related desynchronization (ERD) related to voluntary movement, we designed two experiments. In the first experiment, untrained subjects were required to imagine the action of typing with left or right index finger for about 1 second before real action, whereas they were required to type instantly after instruction in the second experiment. By analyzing spontaneous EEG signals between the instruction and the action, we predicted which finger was used. The prediction accuracy in the first experiment fell from 85% to 71% with the progress of experiment, the average accuracy being 78%, whereas the prediction result was almost random guess in the second experiment. The results demonstrate that (1) ERD patterns are significantly affected by the effective duration of motion imagination, (2) unconscious reduction of this duration can decrease the prediction accuracy. Therefore, when designing subsequent BCI experiments, we should devote our attention to the question of how to keep the effective duration of motion imagination.
Brain ; physiology ; Cortical Synchronization ; Electroencephalography ; Humans ; Man-Machine Systems ; Task Performance and Analysis ; User-Computer Interface

Studying some clinical feature of 85 patients with erythematosus systemic lupus showed that the early and frequent symptoms were essential persistent fever (95.29%), tired and weight loss (91.76%), alopecia (84.7%), menstruation disorder (52.56%). The symptoms were evaluated according to the diagnostic standards of arthropathy association of America including underformity arthritis (92.84%), facial rash (82.35%), renal lesion (71.75%), and discoid rash in the body (38.82%), oral mucosal ulceration (22.35%), multimembraine inflammatory (21.17%) and psychotic disorder (7.05%).
Human Engineering ; Workplace

Using human electroencephalogram (EEG) to control external devices in order to achieve a variety of functions has been focus of the field of brain-computer interface (BCI) research. P300 is experiments which stimulate the eye to produce EEG by using letters flashing, and then identify the corresponding letters. In this paper, some improvements based on the P300 experiments were made??. Firstly, the matrix of flashing letters were modified into words which represent a certain sense. Secondly, the BCI2000 procedures were added with the corresponding source code. Thirdly, the smart car systems were designed using the radiofrequency signal. Finally it was realized that the evoked potentials were used to control the state of the smart car.
Adult ; Automobiles ; Brain ; physiology ; Brain-Computer Interfaces ; Electroencephalography ; instrumentation ; methods ; Event-Related Potentials, P300 ; Evoked Potentials, Visual ; Female ; Humans ; Male ; Man-Machine Systems ; Task Performance and Analysis

BACKGROUND: In 2004, Sharon Keene introduced a video microscope to the hair transplant field and discussed about the benefits such as ergonomics, quality assurance, and easy teaching. In 2009, our clinic set up digital video microscope systems. CCD-chip-loaded hand-held digital video microscope was connected to a 19-inch high definition (HD) LCD monitor. We compared the transection rates and graft-cutting time of two graft-dissecting methods to decide which one is more efficient. METHODS: Two technicians performed follicular unit graft dissection via two different methods of video microscopic and a combination of video microscope for slivering and loupe magnification for graft-cutting. All the procedures were recorded on high-definition digital video camera and cross-checked on the video clips. RESULTS: The transection rate of digital video microscope use was 2.2% while the combination method with 1.6%. For comparison of graft-producing time, the combination method could produce about equal amount of grafts in 186% faster the time. CONCLUSIONS: The work efficiency was greater with the combination method. The total graft productivity was nearly 2 times larger while the transection rates of two methods showed very close results.
Efficiency ; Hair ; Human Engineering ; Transplants

BACKGROUND: Prolonged standing has been hypothesized as a vital contributor to discomfort and muscle fatigue in the workplace. The objective of this study was to develop a decision support system that could provide systematic analysis and solutions to minimize the discomfort and muscle fatigue associated with prolonged standing. METHODS: The integration of object-oriented programming and a Model Oriented Simultaneous Engineering System were used to design the architecture of the decision support system. RESULTS: Validation of the decision support system was carried out in two manufacturing companies. The validation process showed that the decision support system produced reliable results. CONCLUSION: The decision support system is a reliable advisory tool for providing analysis and solutions to problems related to the discomfort and muscle fatigue associated with prolonged standing. Further testing of the decision support system is suggested before it is used commercially.
Fatigue ; Human Engineering ; Muscle Fatigue

Effective and sustainable prevention of work-related musculoskeletal disorders (WR-MSDs) remains a challenge for preventers and policy makers. Coordination of stakeholders involved in the prevention of WR-MSDs is a key factor that requires greater reflection on common knowledge and shared representation of workers' activities among stakeholders. Information on workers' strategies and operational leeway should be the core of common representations, because it places workers at the center of the "work situation system" considered by the intervention models. Participatory ergonomics permitting debates among stakeholders about workers' activity and strategies to cope with the work constraints in practice could help them to share representations of the "work situation system" and cooperate. Sharing representation therefore represents a useful tool for prevention, and preventers should provide sufficient space and time for dialogue and discussion of workers' activities among stakeholders during the conception, implementation, and management of integrated prevention programs.
Administrative Personnel ; Fertilization ; Human Engineering ; Humans

BACKGROUND: This study aimed to investigate the relation between key strike forces and musculoskeletal symptoms (MSS). Moreover, this study presents a key strike force measurement method to be used in a workplace setting. The correlation between key strike force characteristics and MSS was previously studied, but the measurement methods used either a single-key switch or force platforms applied under the keyboard. Most of the studies were conducted in a laboratory setting. The uniqueness of measurement methods in the current study is their ability to measure forces applied to a specific key in a workplace setting and to provide more information about specific key strike forces during typing. METHODS: Twenty-four healthy computer workers were recruited for the study. The demographic questionnaire, and self-reported questionnaires for psychosocial status (General Nordic Questionnaire for Psychological and Social Factors at Work) and for detecting MSS were filled up, which later helped in dividing the participants into two groups (12 participants with pain and 12 without pain). Participants typed a predetermined text that utilized the instrumented keys multiple times. The dynamic forces applied to the keys were recorded and collected, using four thin and flexible force sensors attached to the preselected keys according to their location. RESULTS: The results demonstrated that participants with high levels of MSS, specifically in the back and neck, in the last year exerted significantly higher key strike forces than those with lower levels of symptoms (p < 0.005). CONCLUSION: The key strike force exerted while typing on a keyboard may be a risk factor for MSS, and should therefore be considered in ergonomic evaluations and interventional programs.
Human Engineering ; Methods ; Neck ; Risk Factors ; Strikes, Employee*

BACKGROUND: A unique framework for performance optimization of generation companies (GENCOs) based on health, safety, environment, and ergonomics (HSEE) indicators is presented. METHODS: To rank this sector of industry, the combination of data envelopment analysis (DEA), principal component analysis (PCA), and Taguchi are used for all branches of GENCOs. These methods are applied in an integrated manner to measure the performance of GENCO. The preferred model between DEA, PCA, and Taguchi is selected based on sensitivity analysis and maximum correlation between rankings. To achieve the stated objectives, noise is introduced into input data. RESULTS: The results show that Taguchi outperforms other methods. Moreover, a comprehensive experiment is carried out to identify the most influential factor for ranking GENCOs. CONCLUSION: The approach developed in this study could be used for continuous assessment and improvement of GENCO's performance in supplying energy with respect to HSEE factors. The results of such studies would help managers to have better understanding of weak and strong points in terms of HSEE factors.
Human Engineering* ; Noise ; Passive Cutaneous Anaphylaxis ; Principal Component Analysis