• Geomechanics and Engineering
• /
• 제18권4호
• /
• pp.449-457
• /
• 2019

Physical model tests were first performed to investigate the failure pattern of multiple pillar-roof support system. It was observed in the physical model tests, pillars were design with the same mechanical parameters in model #1, cracking occurred simultaneously in panel pillars and the roof above barrier pillars. When pillars 2 to 5 lost bearing capacity, collapse of the roof supported by those pillars occurred. Physical model #2 was design with a relatively weaker pillar (pillar 3) among six pillars. It was found that the whole pillar-roof system was divided into two independent systems by a roof crack, and two pillars collapse and roof subsidence events occurred during the loading process, the first failure event was induced by the pillars failure, and the second was caused by the roof crack. Then, for a multiple pillar-roof support system, three types of failure patterns were analysed based on the condition of pillar and roof. It can be concluded that any failure of a bearing component would cause a subsidence event. However, the barrier pillar could bear the transferred load during the stress redistribution process, mitigating the propagation of collapse or cutting the roof to insulate the collapse area. Importantly, some effective methods were suggested to decrease the risk of catastrophic collapse, and the deep-hole-blasting was employed to improve the stability of the pillar and roof support system in a room and pillar mine.

• 한국전문물리치료학회지
• /
• 제28권2호
• /
• pp.123-131
• /
• 2021

Background: Only 2% of falls in older adults result in serious injuries (i.e., hip fracture). Therefore, it is important to differentiate injurious versus non-injurious falls, which is critical to develop effective interventions for injury prevention. Objects: The purpose of this study was to a. extract the best features of surface electromyography (sEMG) for classification of injurious falls, and b. find a best model provided by data mining techniques using the extracted features. Methods: Twenty young adults self-initiated falls and landed sideways. Falling trials were consisted of three initial fall directions (forward, sideways, or backward) and three knee positions at the time of hip impact (the impacting-side knee contacted the other knee ("knee together") or the mat ("knee on mat"), or neither the other knee nor the mat was contacted by the impacting-side knee ("free knee"). Falls involved "backward initial fall direction" or "free knee" were defined as "injurious falls" as suggested from previous studies. Nine features were extracted from sEMG signals of four hip muscles during a fall, including integral of absolute value (IAV), Wilson amplitude (WAMP), zero crossing (ZC), number of turns (NT), mean of amplitude (MA), root mean square (RMS), average amplitude change (AAC), difference absolute standard deviation value (DASDV). The decision tree and support vector machine (SVM) were used to classify the injurious falls. Results: For the initial fall direction, accuracy of the best model (SVM with a DASDV) was 48%. For the knee position, accuracy of the best model (SVM with an AAC) was 49%. Furthermore, there was no model that has sensitivity and specificity of 80% or greater. Conclusion: Our results suggest that the classification model built upon the sEMG features of the four hip muscles are not effective to classify injurious falls. Future studies should consider other data mining techniques with different muscles.

• The Journal of Korean Physical Therapy
• /
• 제9권1호
• /
• pp.81-87
• /
• 1997

Although most of Korean PT professors and clinical lecturers has been thought the importance of the PT student's clinical practice, there has got a lot of training problems in clinical field. As the result, of our survey study pointed out trouble of the (1) training duration (2) training credits (3) training evaluation (4) training workbook (5) training fee (6) training hospital numbers and (7) training quality etc, in Korean today's situation. So we suggest the Internship-training system for above half a year after student has got a PT licence, as a desired training model.

• The Journal of Korean Physical Therapy
• /
• 제36권1호
• /
• pp.45-51
• /
• 2024

Purpose: Since core competence-based training is in demand, this study aimed to develop a suitable talent model and major competencies for the Department of Physical Therapy at U University and use it to propose appropriate educational subjects. Methods: This case study was conducted at U university in Gyeongju-si, Gyeongsangbuk-do. To study curricula based on major competence, related documents were analyzed, expert opinions were obtained, and a consumer survey was conducted. Results: U University assigns major competencies for each department, develops subjects accordingly, maps them, and constructs a competency matrix. The four major competencies of physical therapy were defined as musculoskeletal system, nervous system, cardiorespiratory system and sports injury, and physical management abilities. In order to realize these major competencies, U University added subjects to its curriculum. Conclusion: The results of internal and external environmental analysis should be more actively considered to enable changes in subjects at the departmental level. In addition, the setting of major competencies should be subjected to more detailed, specific reviews to maintain the basic principles of major curricula.

• 한국실내디자인학회:학술대회논문집
• /
• 한국실내디자인학회 2001년도 춘계학술발표대회 논문집
• /
• pp.106-111
• /
• 2001

Model house play an important role in the sale of apartments. However, model house can create social and environmental problems. Virtual reality's (VR) use for the creation of model house has been studied as a possible counter measure to these problems. Existing models don't satisfy consumers' queries. A virtual model house can give the experience of seeing a real home through simulation. Also, a virtual model house can allow a home buyer to change the furniture on display or the color of the walls to reflect the consumer's taste in the construction. The internal present condition system using absorption style virtual reality and open style virtual reality are the indispensable tools that are going to take the place of the current model home. A virtual model house is more profitable than a physical model house because of reduced costs and time savings. In addition, a virtual model house can offer new kinds of information that a physical model home can not. This study's purpose is to discuss the desired direction of the virtual model house in this crucial and dynamic period of development.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
• /
• pp.143-150
• /
• 2000

A physical lumped parameter model is proposed for the time domain analysis of dam-reservoir system. The exact solution of transmitting boundary is derived for a semi-infinite 2-D reservoir of constant depth. The characteristics of the solution are examined in both frequency and the domains. Mass and damping coefficient are obtained from asymptotic behavior of the frequency domain solution. Further refinement to the lumped model is made by approximating the kernel function of the convolution integral in the exact solution. Finally a new physical lumped parameter model is proposed that consists of two masses, a spring and two dampers for each mode. It is demonstrated that new lumped parameter model of transmitting boundary can give excellent results.

• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 2003년도 추계학술발표논문집
• /
• pp.291-305
• /
• 2003

In this work we developed the closed-loop model of a paper machine during grade change with the intention to provide a reliable dynamic model to be used in the model-based grade change control scheme. During the grade change, chemical and physical characteristics of paper process change with time. It is very difficult to represent these characteristics on-line by using physical process models. In this work, the wet circulation part and the drying section were considered as a single process and closed-loop identification technique was used to develop the grade change model. Comparison of the results of numerical simulations with plant operation data demonstrates the effectiveness of the model identified.

• 한국농공학회지
• /
• 제32권3호
• /
• pp.67-78
• /
• 1990

A decision support system, Daily Irrigation Network Operation Simulation model (DINOPS) was developed that can adequately describe the physical behavior of an irrigation system. The model is to depict the physical features of complex water allocation schemes of the irrigation system and to simulate the response of the system to different irrigation schemes. The model was validated on the Banweol irrigation district by comparing the simulated canal discharges and paddy water levels with the field data. The operation of the DINOPS model was demonstrated on the irrigation district where several irrigation management practices were evaluated with computing irrigation efficiencies and rainfall effectiveness respectively. The model sensitivity with respect to heights of bund and block diversion rates were analyzed and discussed.

• Geomechanics and Engineering
• /
• 제6권4호
• /
• pp.341-358
• /
• 2014

Uplift response of rectangular anchor plates has been investigated in physical model tests and numerical simulation using Plaxis. The behavior of rectangular plates during uplift test was studied by experimental data and finite element analyses in cohesionless soil. Validation of the analysis model was also carried out with 200 mm and 300 mm diameter of rectangular plates in sand. Agreement between the uplift responses from the physical model tests and finite element modeling using PLAXIS 2D, based on 200 mm and 300 mm computed maximum displacements were excellent for rectangular anchor plates. Numerical analysis using rectangular anchor plates was conducted based on hardening soil model (HSM). The research has showed that the finite element results gives higher than the experimental findings in dense and loose packing of cohesionless soil.

• Geomechanics and Engineering
• /
• 제6권4호
• /
• pp.321-340
• /
• 2014

Uplift response of symmetrical circular anchor plates has been evaluated in physical model tests and numerical simulation using Plaxis. The behavior of circular anchor plates during uplift test was studied by experimental data and finite element analyses in loose sand. Validation of the analysis model was also carried out with 50 mm, 75 mm and 100 mm diameter of circular plates in loose sand. Agreement between the uplift responses from the physical model tests and finite element modeling using PLAXIS 2D, based on 100 mm computed maximum displacements was excellent for circular anchor plates. Numerical analysis using circular anchor plates was conducted based on hardening soil model (HSM). The research has showed that the finite element results gives higher than the experimental findings in the loose sand.