• 한국지능시스템학회논문지
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• 제17권6호
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• pp.843-848
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• 2007

본 논문은 휴머노이드 로봇이 넘어질 경우, 충격에 의한 손상을 최소화하기 위한 자세의 자동 생성 방법을 제안한다. 유전알고리즘(GA)를 사용하여 로봇이 선방 또는 후방으로 넘어질 때 충격량등을 최소화 할 수 있는 관절각들의 궤적을 구하였다. 또한, 다양한 적합도 함수를 정의하여 서로 다른 넘어짐 자세를 생성할 수 있도록 하였다. 제안된 기법의 검증을 위하여 Sony QRIO 로봇에 대해서 ODE 기반 물리적 특성의 시뮬레이션이 가능한 Webots를 이용하여 실험을 수행하였다.

• 한국전문물리치료학회지
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• 제8권3호
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• pp.107-117
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• 2001

Falls are the most serious health problems in elderly population. They are a major cause of premature death, physical injury, immobility, psychosocial dysfunction, and nursing home placement. To reduce the alarming rate of falls and related excessive mortality and morbidity, efforts must be made to detect persons at risk of falling and to prevent or reduce the frequency of falls. To facilitate such approaches, it is essential to find the cause of falling (and under what conditions) of the elderly and the factors that are associated with risk of falling. This study was aimed at designing interventions that minimize risk of falling by ameliorating contributing factors while maintaining or improving patient's mobility.

• 한국전산유체공학회지
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• 제19권2호
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• pp.30-39
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• 2014

We report in this paper the analysis of the motion of a needle and a spring in a viscous fluid under the influence of gravitational force. Lateral shift as well as vertical motion of a needle falling in a viscous fluid has been observed from a simple experiment. We also observed the combined rotation and translation of a falling spring. The trajectory and velocity of the falling needle and the spring were obtained by using an image processing technique. We also conducted numerical simulation for both problems. For the falling-needle problem, we employed a theory; but it turns out that significant correction is required for the solutions to match the numerical and experimental data. For the falling spring problem various theoretical formula were tested for their justification, but none of the existing theories can successfully predict the numerical and experimental results.

• 대한의용생체공학회:의공학회지
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• 제24권3호
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• pp.233-239
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• 2003

측방 낙상에 관계된 상해는 노인들에 있어서 가장 치명적이고 빈번한 의료 문제를 야기한다. 측방 낙상에 의해 발생하는 심각한 결과 중 하나인, 고관절 골절은 넘어진 사람 중 약 1%에서만 발생하지만 고관절 골절은 신체장애, 사망 및 이에 관련된 의료비용의 상승 등을 초래한다. 본 연구에서는 측방 낙상시 고관절 골절에 큰 영향을 미치는 충돌 단계에서의 위험요소를 하중각도로 가정하여 이 요소에 대한 영향과 직립시와 비교하여 상대적인 위험도를 비교하고자 하였다. 실험 조건은 이전 연구자의 자료를 토대로 모사골반을 구성하였고, 이렇게 구성된 모사골반을 진자형 충격 시험기에 고정시키고 충격각도(0$^{\circ}$, 15$^{\circ}$, 30$^{\circ}$)를 변화시켜가며 대퇴골의 동적 거동을 조사하였다. 본 실험을 통하여 하중각도의 변화가 대퇴골 근위부에서의 변형에 영향을 주며, 다른 부위에 비해 대퇴골 경부에 상대적으로 큰 변형이 생겨 골절 가능성이 높다는 것을 확인하였다. 또한 낮은 충격속도에서도 직립 상태에 비해 큰 변형을 보였으며, 변형 분포의 차이도 나타내었다. 따라서 변형 크기의 차이뿐만 아니라 이러한 변형 분포의 차이도 고관절 골절 기전에 영향을 줄 것으로 사료된다.

• 혜화의학회지
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• 제21권2호
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• pp.113-120
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• 2013

The object of this study was to investigate the relation between variables that is related to the general characteristics, fear of falling and falls efficacy. Data were collected from a convenience sample of 105 elders. Fear of falling and falls efficacy are measured structured questionnaires each. This study analyzed by SAS program. There was a significant difference of fear of falling according to education level(p=.003), body mass index(p=.016). There was a significant difference of falls efficacy according to gender(p<.001), education level(p=.047), body mass index(p=.019), number of chronic disease(p=.021). Fear of falling and age(r=0.23, p=.018) had significant positive correlations in the elders. Falls efficacy and number of chronic disease(r=-0.26, p=.010) had significant negative correlations in the elders. Fear of falling and falls efficacy are mutually contradictious concept. Also, both are important for the health of elderly. This result can be used for the elderly care and development of the program for the improvement of the falling efficacy.

• 가정∙방문간호학회지
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• 제25권1호
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• pp.96-104
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• 2018

Purpose: This study compared factors related to fear of falling among women in the early phase of old age based on hand grip strength. Methods: Researchers obtained data of 1,071 women who had participated in the 4th Korean Longitudinal Study of Aging. Data were analyzed using multiple regression analysis. Results: In both groups, fear of falling was positively correlated with falling experience within two years, osteoarthritis-related leg pain, depression, and instrumental daily life abilities; however, self-rated health was negatively correlated. In the low hand grip strength group, self-rated health, osteoarthritis-related leg pain, and hand grip strength accounted for 21.3% of the variance regarding fear of falling. In the normal hand grip strength group, age, self-rated health, fall experience within two years, osteoarthritis-related leg pain, and depression significantly accounted for 16.6% of the variance regarding fear of falling. Conclusion: In applying interventions to prevent falling in women in the early phase of old age, health care workers must verify if women have low hand grip strength and determine whether to focus on fitness improvement through exercise interventions or consider psychological interventions for depression.

• International Journal of Internet, Broadcasting and Communication
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• 제12권2호
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• pp.120-126
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• 2020

Studies are being conducted regarding falling recognition using sensors on smartphonesto recognize falling in human daily life. These studies use a number of sensors, mostly acceleration sensors, gyro sensors, motion sensors, etc. Falling recognition system processes the values of sensor data by using a falling recognition algorithm and classifies behavior based on thresholds. If the threshold is ambiguous, the accuracy will be reduced. To solve this problem, Deep learning was introduced in the behavioral recognition system. Deep learning is a kind of machine learning technique that computers process and categorize input data rather than processing it by man-made algorithms. Thus, in this paper, we propose a falling recognition application system using deep learning based on smartphones. The proposed system is powered by apps on smartphones. It also consists of three layers and uses DataBase as a Service (DBaaS) to handle big data and address data heterogeneity. The proposed system uses deep learning to recognize the user's behavior, it can expect higher accuracy compared to the system in the general rule base.

• 대한기계학회논문집B
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• 제33권7호
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• pp.495-505
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• 2009

A two-dimensional circular cylinder freely falling in a channel has been simulated by using immersed boundary - lattice Boltzmann method (IB-LBM) in order to analyze the characteristics of motion originated by the interaction between the fluid flow and the cylinder. The wide range of the solid/fluid density ratio has been considered to identify the effect of the solid/fluid density ratio on the motion characteristics such as the falling time, the transverse force and the trajectory in the streamwise and transverse directions. In addition, the effect of the gap between the cylinder and the wall on the motion of a two-dimensional freely falling circular cylinder has been revealed by taking into account a various range of the gap size. As the cylinder is close to the wall at the initial dropping position, vortex shedding in the wake occurs early since the shear flow formed in the spacing between the cylinder and the wall drives flow instabilities from the initial stage of freely falling. In order to consider the characteristics of transverse motion of the cylinder in the initial stage of freely falling, quantitative information about the cylinder motion variables such as the transverse force, trajectory and settling time has been investigate.

• 설비공학논문집
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• 제18권11호
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• pp.867-873
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• 2006

Vertical falling liquid film is extensively used in heat and mass transfer processes of many applications, such as evaporative coolers, cooling towers, and absorption chillers. In such cases, it is required that the falling film spreads widely in the surface forming thin liquid film to enlarge contact surface. An addition of surface active agent to a falling liquid film or hydrophilic surface treatment affects the fluid physical properties of the film. Surfactant addition not only decreases contact angle between the liquid and solid surface but also changes the surface from hydrophobicity to hydrophilicity. In this study, the effects of contact angle on falling film characteristics over a vertical surface have been investigated experimentally. The contact angle is varied either by an addition of surfactant to the liquid or by hydrophilic surface treatment. It is found that the wetted area is increased and film thickness is decreased by the hydrophilic treatment as compared with those of other surfaces. With this hydrophilic treatment, the falling liquid film spreads out widely in the surface. As surfactant concentration is increased, wetted area is also increased and the film thickness is substantially decreased.

• 한국과학교육학회지
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• 제10권2호
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• pp.49-54
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• 1990

The purpose of this paper is to promote the physics study of high school students with computer. A computer simulation for falling motion is used to provide the students a chance to study by themselves viewing the concrete motion pictures of computer. By this simulation program, the students can observe various movements of a falling body with calculated distance according to falling time.