• PNF and Movement
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• 제20권3호
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• pp.431-441
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• 2022

Purpose: The purpose of this study was to compare the changes in the contact area, maximum pressure, maximum mean pressure, and maximum force of functional insoles and general insoles when walking. Methods: Foot pressure was measured by the ignition of functional insoles and general insoles on Company N shoes. The foot pressure was measured using a precision pressure distribution meter (Pedar - X mobile system, Novel, Germany). Each insole sensor contained 99 independent cells and was inserted between the foot and the shoe. A wireless Bluetooth-type program was used to measure the pressure detected by the measuring insoles. In order to eliminate adaptation and fatigue caused by wearing the guide during the experiment, sufficient rest was taken between each experiment, and the wearing order was randomly selected. Results: Functional insole significantly increased the forefoot and midfoot (medial, lateral) (p<0.05), while total foot, forefoot, and rearfoot peak pressure significantly decreased (p < 0.05) compared to the general insole. Conclusion: In the functional insole, a high contact area was measured inside, even in the middle of the foot, leading to a proper change in foot pressure. It was confirmed that the contact area was reduced and dispersion occurred well. In addition, it was found that the maximum pressure in the front and back of the entire foot was reduced, so the weight pressure dispersion in the functional insole was evenly distributed, and the maximum average pressure change was similar.

• PNF and Movement
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• 제20권3호
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• pp.451-459
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• 2022

Purpose: Temporomandibular disorder (TMD) is a common musculoskeletal problem that causes pain in and disability of masticatory muscles, the temporo-mandibular joint (TMJ), and related structures. The purpose of this study was to compare pressure pain thresholds (PPTs) of masticatory muscles, cervical ranges of motion (ROM), and pelvic mobility during gait of subjects with or without TMD. Methods: In this study, pain thresholds and changes in the mobility of the cervical vertebrae and pelvis were measured in 25 patients with TMD and 25 healthy controls. Using a pressure algometer, the pressure pain thresholds (PPTs) of the masseter and temporalis muscles were measured in both groups. A gyroscope sensor with a mobile application was used to determine cervical ROM in the frontal and sagittal planes. A 3D-motion analysis system was used to evaluate pelvic mobility in the sagittal, frontal, and transverse planes during gait. Results: The TMD group showed significantly decreased PPTs of masseter and temporalis muscles compared with the control group (p < 0.05). Cervical ROM in flexion, extension, and lateral bending were significantly decreased in the TMD group compared with the control group (p < 0.05). In addition, antero-posterior pelvic tilt was significantly decreased in the TMD group (p < 0.05). Conclusion: The results of the current study suggest that there are close anatomical and functional relationships between TMD and muscle chains related to the cervical spine and pelvis. Therefore, more comprehensive body posture assessments, especially of painful areas, should be undertaken when studying TMD patients.

• 대한정형도수물리치료학회지
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• 제29권2호
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• pp.77-91
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• 2023

Background: Congenital muscular torticollis results in reduced head mobility, such as cervical rotation, due to the abnormal size and contraction of the sternocleidomastoid muscle. Korea Pediatric integrative manual therapy and stretching are recommended to improve head rotation upper cervical spine mobility. Therefore, in this study, the effect of the new PIMT was investigated. Methods: The patient is a 3.5 month-old diagnosed with congenital muscular torticollis (CMT). Due to the limitation of head rotation and cervical spine rotation and flexion mobility, the child visited a rehabilitation center and after diagnosis, Pediatric integrative manual therapy (PIMT) treatment was performed five times a week for a total of 15 weeks. The child's head rotation and flexion limitation and plagiocephaly were evaluated. Results: In conclusion, this study shows that compared to other treatments, PIMT approach is a more effective treatment for improving head rotation and cervical limitation for range of motion in CMT infants. Conclusion: PIMT approach was effective in improving cervical rotation and Head lateral flexion mobility and plagiocephaly in CMT patients.

• Geomechanics and Engineering
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• 제30권6호
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• pp.539-549
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• 2022

Accidental anchor drop can cause disturbances to seabed materials and pose significant threats to the safety and serviceability of submarine structures such as pipelines. In this study, a series of anchor drop tests was carried out to investigate the penetration mechanism of a Hall anchor in sand and clay. A special anchor drop apparatus was designed to model the inflight drop of a Hall anchor. Results indicate that Coriolis acceleration was the primary cause of large horizontal offsets in sand, and earth gravity had negligible impact on the lateral movement of dropped anchors. The indued final horizontal offset was shown to increase with the elevated drop height of an anchor, and the existence of water can slow down the landing velocity of an anchor. It is also observed that water conditions had a significant effect on the influence zone caused by anchors. The vertical influence depth was over 5 m, and the influence radius was more than 3 m if the anchor had a drop height of 25 m in dry sand. In comparison, the vertical influence depth and radius reduced to less than 3 m and 2 m, respectively, when the anchor was released from 10 m height and fell into the seabed with a water depth of 15 m. It is also found that the dynamically penetrating anchors could significantly influence the earth pressure in clay. There is a non-linear increase in the measured penetration depth with kinematic energy, and the resulted maximum earth pressure increased dramatically with an increase in kinematic energy. Results from centrifuge model tests in this study provide useful insights into the penetration mechanism of a dropped anchor, which provides valuable data for design and planning of future submarine structures.

• 한국군사과학기술학회지
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• 제26권1호
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• pp.102-112
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• 2023

This research mainly focuses on the transport and dispersion of chemical agent plume according to the Lagrangian Puff Model and Lagrangian Particle Model of NBC_RAMS(Nuclear, Biological, Chemical Reporting And Modeling S/W System). NBC_RAMS was developed with the purposes of estimating the fate of Chemical, Biological, and Radioactive(CBR) agent plumes and evaluating damages in the Republic of Korea. First, it calculates the local weather pattern, i.e. wind speed, wind direction, and temperature, by considering the effects of land uses and topography. The plume behaviors are calculated by adopting the Lagrangian Puff Model(LPFM) or Lagrangian Particle Model(LPTM). In this research, we assumed a virtual chemical agent exposure event in a stable atmospheric condition during the summer season. The plume behaviors were estimated by both LPFM and LPTM on the used area(urbanized and dry area) and the agricultural land. The higher heat flux in the used area led to stronger winds and further downward movement moving of the chemical agent than the farmland. The lateral dispersion of the chemical plume was emphasized in the Lagrangian Puff Model because it adopted Gaussian distribution.

• 한국지반공학회논문집
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• 제22권10호
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• pp.121-129
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• 2006

쇄석기둥 공법은 성토제방, 교량교대기초, 오일탱크와 같은 침하에 민감한 구조물의 지지력 증대 및 압밀 촉진에 효과적인 지반 개량 공법이다. 쇄석기둥 공법은 지반의 지지력 증대, 침하감소, 측방유동 방지 및 액상화 방지 등의 효과를 기대할 수 있다. 최근 들어서는 쇄석기둥의 외벽을 토목섬유로 보강(감쌈) 구속력을 증가시켜 줌으로써 쇄석기둥 지반의 하중지지력을 개선시키는 공법에 대한 관심이 증가하고 있으나, 지오그리드 보강 쇄석기둥 공법에 대한 연구는 체계화되어 있지 않는 실정이다. 본 연구에서는 실내모형실험을 통해 지오그리드로 보강 쇄석기둥의 하중지지력 특성 및 파괴형태를 고찰하였으며, 실험결과를 통해 지오그리드로 보강하지 않은 쇄석기둥공법에 비해 지오그리드보강 쇄석기둥공법의 지지력 개선효과가 크게 나타남을 알 수 있다.

• 대한치과교정학회지
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• 제53권2호
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• pp.125-136
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• 2023

Before progress was recently made in the application of temporary anchorage devices (TADs) in bio-mechanical design, orthodontists were rarely able to intrude molars to reduce upper posterior dental height (UPDH). However, TADs are now widely used to intrude molars to flatten the occlusal plane or induce counterclockwise rotation of the mandible. Previous studies involving clinical or animal histological evaluation on changes in periodontal conditions after molar intrusion have been reported, however, studies involving human histology are scarce. This case was a Class I malocclusion with a high mandibular plane angle. Upper molar intrusion with TADs was performed to reduce UPDH, which led to counterclockwise rotation of the mandible. After 5 months of upper molar intrusion, shortened clinical crowns were noticed, which caused difficulties in oral hygiene and hindered orthodontic tooth movement. The mid-treatment cone-beam computed tomography revealed redundant bone physically interfering with buccal attachment and osseous resective surgeries were followed. During the surgeries, bilateral mini screws were removed and bulging alveolar bone and gingiva were harvested for biopsy. Histological examination revealed bacterial colonies at the bottom of the sulcus. Infiltration of chronic inflammatory cells underneath the non-keratinized sulcular epithelium was noted, with abundant capillaries being filled with red blood cells. Proximal alveolar bone facing the bottom of the gingival sulcus exhibited active bone remodeling and woven bone formation with plump osteocytes in the lacunae. On the other hand, buccal alveolar bone exhibited lamination, indicating slow bone turnover in the lateral region.

• 대한토목학회논문집
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• 제29권1B호
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• pp.73-81
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• 2009

본 연구에서는 개수로 흐름에서 오염물질 이동 현상에 대한 이차흐름의 영향을 분석하였다. 운동량 방정식과 스칼라 수송 방정식에서의 난류 폐합을 위해 레이놀즈응력 모형 및 GGDH 모형을 사용하였다. 개발된 모형을 이용하여 조 세립상의 횡방향 연속구조를 갖는 개수로 흐름에서의 오염물질 이동에 대한 이차흐름의 영향을 분석하였다. 그 결과, 이차흐름의 영향으로 인해 최대 농도 값의 발생 위치가 이동하는 것으로 나타났으며, 농도 분포 역시 정규 분포에서 거리에 따라 점차 왜곡 되는 것으로 확인되었다. 또한, 이차흐름의 영향으로 자유수면 근처에서는 매끄러운 하상에 비해 거친 하상에서의 오염물질 농도가 더 크게 발생되었으며, 스칼라-흐름률을 계산한 결과, 오염물질의 수직방향 확산은 매끄러운 하상에 비해 거친 하상에서 더 빨리 진행되는 것으로 확인되었다. 한편, 농도 분포 변화에 대한 이차흐름 및 스칼라-흐름률의 영향을 살펴보기 위하여 스칼라 수송률 분석을 수행하였다.

• Journal of Positioning, Navigation, and Timing
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• 제12권4호
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• pp.437-445
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• 2023

A space system refers to a network of sensors, ground systems, and space-craft operating in space. The security of space systems relies on information systems and networks that support the design, launch, and operation of space missions. Characteristics of space operations, including command and control (C2) between space-craft (including satellites) and ground communication, also depend on wireless frequency and communication channels. Attackers can potentially engage in malicious activities such as destruction, disruption, and degradation of systems, networks, communication channels, and space operations. These malicious cyber activities include sensor spoofing, system damage, denial of service attacks, jamming of unauthorized commands, and injection of malicious code. Such activities ultimately lead to a decrease in the lifespan and functionality of space systems, and may result in damage to space-craft and, lead to loss of control. The Cybersecurity Adversarial Tactics, Techniques, and Common Knowledge (ATT&CK) matrix, proposed by Massachusetts Institute of Technology Research and Engineering (MITRE), consists of the following stages: Reconnaissance, Resource Development, Initial Access, Execution, Persistence, Privilege Escalation, Defense Evasion, Credential Access, Discovery, Lateral Movement, Collection, Command & Control, Exfiltration, and Impact. This paper identifies cybersecurity activities in space systems and satellite navigation systems through the National Institute of Standards and Technology (NIST)'s standard documents, former U.S. President Trump's executive orders, and presents risk management activities. This paper also explores cybersecurity's tactics attack techniques within the context of space systems (space-craft) by referencing the Sparta ATT&CK Matrix. In this paper, security threats in space systems analyzed, focusing on the cybersecurity attack tactics, techniques, and countermeasures of space-craft presented by Space Attack Research and Tactic Analysis (SPARTA). Through this study, cybersecurity attack tactics, techniques, and countermeasures existing in space-craft are identified, and an understanding of the direction of application in the design and implementation of safe small satellites is provided.

• Geomechanics and Engineering
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• 제35권6호
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• pp.617-626
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• 2023

In this study, three-dimensional numerical parametric study was conducted to explore deformation mechanisms of grouped piled-raft-foundation due to lateral load in clays. Effects of load intensity, loading angle, soil stiffness, pile diameter, pile spacing and pile length on foundation deformations were explored. It is found that the smallest and largest movements of pile foundation are induced when the loading angles are 0° and 30°~60°, respectively. By increasing loading angle from 0° to 30°~60°, the resultant horizontal movements and settlements increase by up to 20.0% and 57.1%, respectively. Since connection beams can substantially increase integrity of four piled raft foundation, resultant horizontal movements, settlements and bending moments induced in the piled raft foundation decrease by up to 54.0%, 8.8% and 46.3%, respectively. By increasing soil stiffness five times, resultant horizontal movements and settlements of pile foundation decrease by up to 61.7% and 13.0%, respectively. It is indicated that effects of connection beam and soil stiffness on settlements of pile foundation are relatively small. When pile diameter is less than 1.4 m, deformations of piled raft foundation decrease substantially as a reduction in the pile diameter. Two dimensional groups are proposed to develop calculation charts of horizontal movements and settlements of pile foundation. The proposed calculation charts can directly estimate movements of piled raft foundation under arbitrary loading, ground and pile conditions.