Background: Loss of sagittal balance can lead to excessive thoracolumbar (TL) kyphosis, which is a postural impairment characterized by an increase in kyphotic curvature in these two regions of the spine. Excessive TL kyphosis has been shown to adversely affects quality of life and activities of daily living (ADL). Objectives: This study aimed to investigate immediate spinal motion and resultant postural changes after the application of single thoracic extension mobilization. This was compared to the application of two extension mobilizations, one of which was applied to the lumbar region in the second group of patients with excessive TL kyphosis. Design: Quasi-experimental study. Methods: A total of 53 participants (71.6 years, 20 male/33 female) were recruited. All participants had greater than 40° of TL kyphosis, as measured with a single gravity-dependent inclinometer positioned over the T1 spinous process. One group received thoracic extension mobilization only, whereas the other group received both thoracic and lumbar extension mobilization. Results: Both groups demonstrated an improvement (decrease) in the thoracolumbar kyphosis angle. The group that received thoracic mobilization alone demonstrated a 6.46° change (P<0.0001), while the group that received both mobilizations demonstrated a change of 11.96° (P<0.0001). Combined mobilization applied to both the thoracic and lumbar regions resulted in a significantly greater change (reduction) in TL kyphosis (5.50°, P<0.0001). Conclusion: The results demonstrate that the addition of a second mobilization to the lumbar region results in greater active TL extension and reduced TL kyphosis. Clinicians treating patients with excessive kyphotic curvature should be mindful of the contribution of the lumbar region to loss of sagittal balance. The addition of this simple manual mobilization to the lumbar region appears to yield better short-term improvements in patients with overly kyphotic spinal posture.

Fault detection in electromechanical systems plays a significant role in product quality and manufacturing efficiency during the transition to smart manufacturing. Because collecting a sufficient number of datasets under faulty conditions of the system is challenging in practical industrial sites, unsupervised fault detection methods are mainly used. Although fault datasets accumulate during machine operation, it is not straightforward to utilize the information it contains for fault detection after the deep learning model has been trained in an unsupervised manner. However, the information in fault datasets is expected to significantly contribute to fault detection. In this regard, this study aims to validate the effectiveness of the transition from unsupervised to supervised learning as fault datasets gradually accumulate through continuous machine operation. We also focus on experimentally analyzing how changes in the learning paradigm of the deep learning model and the output representation affect fault detection performance. The results demonstrate that, with a small number of fault datasets, a supervised model with continuous outputs as a regression problem showed better fault detection performance than the original model with one-hot encoded outputs (as a classification problem).

The purpose of this study is to measure and analyze the number of chest compressions, chest compressions, depth of chest compressions, ventilation, duration of interruption, and accuracy in college students when eyewitness cardiac arrest occurs. The results of the experiment are as follows.(1) The result of the difference in the number of chest compressions was that A was a 20-year-old woman with an average of 114 chest compressions. E was a 22-year-old man with 96 chest compressions, and J was a 24-year-old woman with 109 chest compressions. (2) The result of the difference in chest compressibility depth was that A was a woman in her 20s with an average chest compression depth of 5.0 to 5.2 cm, E was a man in his 20s with an average chest compression depth of 5.0 to 5.4 cm, and J was a woman in her 20s with an average chest compression depth of 5.1 to 5.5 cm. (3) Ventilation was performed for A, E, and J. (4) CPR discontinuation time (second) was performed for a 20-year-old woman for 0 seconds, E was for a 22-year-old man for 5 seconds, and J was a 24-year-old woman for 5 seconds or less. (5) CPR accuracy was found to be 95.2% for a 20-year-old woman, E was found to be a 22-year-old man for 79.6% for a 22-year-old man, and J was found to be 86% for a 24-year-old woman on average. In order to properly cope with an emergency situation in which cardiac arrest occurs, it is confirmed that CPR practice should be sufficiently performed in advance to improve the accuracy of cardiac pressure, and CPR should be performed when cardiac arrest patients occur by maintaining skills through steady retraining.

Our study experimentally evaluates the structural characteristics of a Cone-Shaped Friction Isolator (CFI) as part of research on sliding bearings. With its relatively simple configuration and effective restoring mechanism, the CFI has significant practical implications for structural engineering. We designed the shape and components of the CFI, and its operation and restoring mechanisms were theoretically reviewed. A prototype of the CFI was developed, and structural characteristic experiments were conducted, focusing on design parameters such as the cone’s inclination angle, the friction coefficient of the contact surface, the magnitude of the vertical load applied to the isolator, and the horizontal loading frequency. The experimental results provide valuable insights into the structural characteristics of devices in terms of critical shear force and restoring shear force.

Most reinforced concrete (RC) school buildings constructed in the 1980s have seismic vulnerabilities due to low transverse reinforcement ratios in columns and beam-column joints. In addition, the building structures designed for only gravity loads have the weak-columnstrong- beam (WCSB) system, resulting in low lateral resistance capacity. This study aims to investigate the lateral resistance capacities of a two-story, full-scale school building specimen through cyclic loading tests. Based on the experimental responses, load-displacement hysteresis behavior and story drift-strain relationship were mainly investigated by comparing the responses to code-defined story drift limits. The test specimen experienced stress concentration at the bottom of the first story columns and shear failure at the beam-column joints with strength degradation and bond failure observed at the life safety level specified in the code-defined drift limits for RC moment frames with seismic details. This indicates that the seismically vulnerable school building test specimen does not meet the minimum performance requirements under a 1,400-year return period earthquake, suggesting that seismic retrofitting is necessary.

This paper aims to quantify the retrofit effect of the Bolt Prefabricated Concrete-Filled Tube reinforcement method on non-seismic school reinforced concrete building through static cyclic loading experiments. To achieve the objective, two-story specimens including a non-retrofitted frame(NRF) and a Bolt Prefabricated Concrete-Filled Tube Reinforcement Frame(BCRF) were tested under static cyclic loading, and the lateral resistant capacities were compared in terms of maximum strength, initial stiffness, effective stiffness, and total energy dissipation. In addition, the load-displacement curves were compared to the story drift limit specified in Seismic Performance Evaluation and Retrofit Manual for School Facilities to investigate if the retrofitted frame was satisfied in target performance(life safety). Experimental results showed that BCRF successfully met the target performance, with a 200% increase in maximum strength and a 300% increase in energy dissipation capacity. Additionally, both initial stiffness and effective stiffness improved by more than 30% compared to NRF. Furthermore, BCRF exhibited an effect that delayed the occurrence of bond failure.

국내 도심지에 적용하고 있는 중앙버스정류장의 포장은 주로 아스팔트 포장으로 시공되어 있으나 중차량인 버스의 하 중으로 인해 포장 파손 사례가 증가하여 시민들의 안전에 악영향을 미치고 있으며 유지보수 비용이 매년 증가하고 있다. 서울시에서는 이러한 문제를 해결하기 위해 국내 최초로 중앙버스정류장 신설 구간에 현장타설 방식으로 연속철근 콘크 리트 포장(CRCP)을 시공하였다. 본 연구에서는 이러한 구간의 연속철근 콘크리트 포장에 대한 이동차량 하중에 의한 동 적 거동 특성을 분석하고자 포장 슬래브에 콘크리트 변형률계를 설치하고 덤프트럭을 통과시키며 동적 하중 재하 실험 을 수행하였다. 실험에서는 이동차량의 속도를 다양하게 변화시켜 차량 속도에 따른 포장 슬래브의 동적 거동을 비교 분 석하였으며 이동차량이 CRCP의 여러 위치에서 정지하도록 하여 정지 위치에 따른 거동도 분석하였다. 실험 결과, 차량 이 CRCP를 통행할 경우 차량 속도 및 정지 위치에 따른 포장 슬래브의 동적 변형률은 매우 유사한 것으로 분석되었다.

In this study, the initial operation characteristics of a multi-type cooling system with three indoor units using an inverter compressor were investigated experimentally using a calorimeter. The operating characteristics of the cooling system were confirmed under the full load condition of simultaneous operation of three rooms and the partial load condition of individual operation of two or one room under the standard cooling conditions. The capacities of A, B and C are 50, 20, and 30% of the total capacity, respectively. The 3 room combination has 100% capacity, the 2 room combination has 50, 70 and 80% capacity, and the 1 room has 20, 30, and 50% capacity. The compressor condensing and evaporating pressures, the electronic expansion valve openings of indoor units A, B, and C, and the compressor operating frequencies were measured for 10 minutes after the cooling system was started. During the initial operation, the changes in the operating time and opening of the electronic expansion valve varied depending on the indoor unit combination and the operating load, and the relationship between the compressor pressure and the operating frequency was found.

For experimental studies on the production of MR fluid for MR dampers, MR fluid with a viscosity of 506 cP and a density of 2.6 g/cc was produced. In order for MR fluid to have suitable performance for MR dampers, it is important to select surfactants, magnetic particles, base oil, and characteristic additives to obtain high damping force and maintain physical and chemical properties. In order to investigate the redispersibility of MR fluid, viscosity, density, saturation magnetic flux density, dispersibility, and temperature effects were evaluated. A particle size distribution meter and a vibrating magnetometer were used, and a yield stress and redispersion device were developed to obtain the yield stress of the MR fluid. The recovery rate of MR fluid was approximately 97% at 0.2% succinic acid coating and 8% anti-settling agent. And when current is applied, the viscosity increases by more than 90% due to magnetic properties.