• 센서학회지
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• 제32권5호
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• pp.320-327
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• 2023

In this study, an FPGA-based sealer inspection system was developed to inspect the sealer applied to install vehicle glass on a car body. The sealer is a liquid or paste-like material that promotes adhesion such as sealing and waterproofing for mounting and assembling vehicle parts to a car body. The system installed in the existing vehicle design parts line does not detect the sealer in the glass rotation section and takes a long time to process. This study developed a line laser camera sensor and an FPGA vision signal processing module to solve this problem. The line laser camera sensor was developed such that the resolution and speed of the camera for data acquisition could be modified according to the irradiation angle of the laser. Furthermore, it was developed considering the mountability of the entire system to prevent interference with the sealer ejection machine. In addition, a vision signal processing module was developed using the Zynq-7020 FPGA chip to improve the processing speed of the algorithm that converted the profile to the sealer shape image acquired from a 2D camera and calculated the width and height of the sealer using the converted profile. The performance of the developed sealer application inspection system was verified by establishing an experimental environment identical to that of an actual automobile production line. The experimental results confirmed the performance of the sealer application inspection at a level that satisfied the requirements of automotive field standards.

• 항공우주시스템공학회지
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• 제18권3호
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• pp.17-26
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• 2024

항공기 엔진은 비행 중 고온, 고압과 터빈 축의 회전으로 인한 응력이 발생한다. 이러한 하중으로 인해 구조 내/외부에 미세한 균열이 발생할 수 있다. 이는 구조적 결함으로 이어져 부품의 수명에 악영향을 줄 수 있다. 이러한 현상을 사전에 방지하고자 균열에 대한 유한요소해석이 진행된다. 하지만 이 과정은 반복적인 균열 모델링이 이루어져 많은 시간과 노력을 수반한다. 그러므로 본 논문에서는 유한요소모델 기반의 균열 모델링 기법을 개발하였다. 균열 모델링에는 점 간의 연결에 제한을 가지고 공간을 삼각 분할하는 Constrained Delaunay Triangulation(CDT)을 사용하였다. 반타원 균열을 가지는 평판과 원통형 용기에 대한 응력확대계수 비교를 통해 기법을 검증하였으며, 균열 해석에 유용함을 보였다.

• Computers and Concrete
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• 제33권5호
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• pp.535-544
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• 2024

In the rapidly advancing landscape of computer vision (CV) technology, there is a burgeoning interest in its integration with the construction industry. Camera calibration is the process of deriving intrinsic and extrinsic parameters that affect when the coordinates of the 3D real world are projected onto the 2D plane, where the intrinsic parameters are internal factors of the camera, and extrinsic parameters are external factors such as the position and rotation of the camera. Camera pose estimation or extrinsic calibration, which estimates extrinsic parameters, is essential information for CV application at construction since it can be used for indoor navigation of construction robots and field monitoring by restoring depth information. Traditionally, camera pose estimation methods for cameras relied on target objects such as markers or patterns. However, these methods, which are marker- or pattern-based, are often time-consuming due to the requirement of installing a target object for estimation. As a solution to this challenge, this study introduces a novel framework that facilitates camera pose estimation using standardized materials found commonly in construction sites, such as concrete forms. The proposed framework obtains 3D real-world coordinates by referring to construction materials with certain specifications, extracts the 2D coordinates of the corresponding image plane through keypoint detection, and derives the camera's coordinate through the perspective-n-point (PnP) method which derives the extrinsic parameters by matching 3D and 2D coordinate pairs. This framework presents a substantial advancement as it streamlines the extrinsic calibration process, thereby potentially enhancing the efficiency of CV technology application and data collection at construction sites. This approach holds promise for expediting and optimizing various construction-related tasks by automating and simplifying the calibration procedure.

• 로봇학회논문지
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• 제19권2호
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• pp.159-168
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• 2024

Lower limb amputees are increasing due to various reasons. It is difficult for lower limb amputees to walk without an assistive device such as a prosthetic leg. In this paper, an electronically controlled knee-type prosthetic leg with a 4-bar linkage structure for lower limb amputees was developed. The knee-type prosthetic leg has a 4-bar linkage structure and assists walking by using an integrated drive module. The torque is 90 Nm, the rotation speed is up to 120 deg, and it weight 1.9 kg, so it is lighter than a commercial prosthetic leg, so it can be used for a long time because there is less fatigue when walking. An integrated control board was developed by applying various sensors and microprocessor. The motor drive and encoder are built into the integrated drive module. The integrated control board and integrated drive module communicate using CAN. When a lower limb amputee wears a knee-type prosthetic leg and walks, it shows a shape similar to the swing phase graph of a normal people, and it is possible to walk naturally while walking.

• 대한정형도수물리치료학회지
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• 제30권1호
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• pp.29-42
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• 2024

Background: This study aimed to determine the effects of training on breathing re-education on pain and dysfunction levels, posture, quality of life (QoL), and pulmonary function in patients. Methods: This study included 34 patients with chronic neck pain and upper thoracic breathing pattern were included. The participants were assigned to either the routine physical therapy program (RPTP) (CG; n=17) or RPTP and breathing pattern re-education training (EG; n=17). The CG and EG groups performed RPTP for 40 minutes, and only the EG groups performed breathing re-education training for 10 minutes. Exercises were performed thrice weekly for both groups. Level of pain and dysfunction, posture, QoL and pulmonary function status were assessed before and after the intervention. Results: After four weeks of intervention, numeric pain rating scale (NPRS), Korean version of neck disability index, cranio-vertebral angle, cranial rotation angle, and 12-item short form health survey-physical and mental component summaries had significant differences before and after intervention in both groups (p<.01). However, only NPRS, forced vital capacity, forced expiratory volume in 1s, and maximum voluntary ventilation showed significant interactions between the two groups and measurement time (p<.01). Conclusion: Breathing re-education training and RPTP may be optimal for patients with chronic neck pain and may be more effective in improving neck pain and pulmonary function.

• Hip & pelvis
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• 제35권4호
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• pp.268-276
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• 2023

Purpose: Resection remains the most reliable treatment for established heterotopic ossification, despite questions regarding its effectiveness due to the potential for complications. This study evaluated the clinical outcomes and complications of neurogenic heterotopic ossification (NHO) resection in stroke patients' ankylosed hips. Materials and Methods: We retrospectively analyzed nine hip NHO resections performed on seven patients from 2010 to 2018. The pre- and postoperative range of motion of the operated hip were compared. Analysis of postoperative complications, including infection, recurrence, iatrogenic fracture, and neurovascular injury was performed. Results: The mean operative time was 132.78±21.08 minutes, with a mean hemoglobin drop of 3.06±0.82 g/dL within the first postoperative week. The mean duration of postoperative follow-up was 52.08±28.72 months for all patients. Postoperative range of motion showed improvement from preoperative. Flexion and external rotation (mean, 58.89±30.60° and 16.67±18.03°, respectively) showed the greatest gain of motion of the operated hip joint. Postoperative infections resolved in two cases through surgical debridement, and one case required conversion to total hip arthroplasty due to instability. There were no recurrences, iatrogenic fractures, or neurovascular injuries. Conclusion: Resection is a beneficial intervention for restoring the functional range of motion of the hip in order to improve the quality of life for patients with NHO and neurological disorders. We recommend performance of a minimal resection to achieve a targeted functional arc of motion in order to minimize the risk of postoperative complications.

• Korean Journal of Radiology
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• 제21권12호
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• pp.1374-1382
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• 2020

Objective: To determine whether ultrasonography at initial presentation can help assess the clinical severity of congenital muscular torticollis (CMT) in infants without a sternocleidomastoid muscle (SCM) mass. Materials and Methods: This retrospective study included 71 infants aged less than 12 months (4.1 ± 2.3 months) with non-mass CMT. The clinical severity was divided into three grades (groups 1-3) based on the degree of lateral head bending or cervical rotation. The difference (SCM-D) and ratio (SCM-R) between the maximal thickness of the affected and non-affected SCMs were obtained using transverse and longitudinal ultrasonography. The sonographic echotexture and echogenicity of the involved SCM were reviewed. Results: A significant difference was observed in the SCM-D (0.42 ± 0.30 mm in group 1; 0.74 ± 0.50 mm in group 2; 1.14 ± 0.85 mm in group 3; p = 0.002) and SCM-R (1.069 ± 0.067 in group 1; 1.129 ± 0.087 in group 2; 1.204 ± 0.150 in group 3; p = 0.001) among the groups when measured along the longitudinal but not along the transverse ultrasonography plane. The areas under the curves of the SCM-R and SCM-D measured by longitudinal ultrasonography were 0.731 (p < 0.001) and 0.731 (p < 0.001) for group 1 versus groups 2-3. The proportions of heterogeneous echotexture or hyperechogenicity in the involved SCM did not differ significantly among the three clinical groups (all p > 0.05). Conclusion: Ultrasonography can aid in assessing the clinical severity of CMT in infants without an SCM mass at the time of initial diagnosis. The SCM-R and SCM-D helped grade the clinical severity when obtained by longitudinal scan.

• 대한물리의학회지
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• 제19권1호
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• pp.95-105
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• 2024

PURPOSE: This study aimed to utilize the International Classification of Functioning, Disability, and Health (ICF) tool to identify a problem list and explore intervention effects using proprioceptive neuromuscular facilitation (PNF) for improving the crosswalk performance of patients who have undergone a bilateral hip arthroplasty. METHODS: The subject of this study was a 43-year-old male who had undergone a bilateral hip arthroplasty. To address the subject's functional status, a clinical decision-making process was carried out in the order of examination, evaluation, diagnosis, prognosis, intervention, and outcome. Patient information during the examination was collected using the ICF core set. The evaluation involved listing the items of each problem using the ICF assessment sheet and identifying the interaction between activity limitations and the impairment level. The diagnosis explicitly described the causal relationships derived from the evaluation using ICF terminology. The prognosis presented activity goals, body function, and structured goals in terms of the activity and participation levels that needed to be achieved for an individual's functional status. The intervention approached problems through the four components of the PNF philosophy, namely basic principles and procedures, techniques, and patterns, in an indirect-direct-task sequence. Results were compared before and after the intervention using the ICF evaluation display. RESULTS: The results of the study showed that the primary activity limitation, which was the walking time across the crosswalk, showed improvement, and the trunk's counter rotation and the weight-bearing capacity of both the lower limbs, which were impairment level indicators, were enhanced. CONCLUSION: This study suggests that PNF intervention strategies will serve as a positive approach for improving crosswalk walking in patients with bilateral hip arthroplasty.

• Steel and Composite Structures
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• 제52권4호
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• pp.405-418
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• 2024

To study the influence of different reduced beam section (RBS) on the mechanical performance of modular boltedwelded hybrid connection joints (MHCJs), this article uses ABAQUS to establish and verify the finite element model (FEM) of the test specimens on the basis of quasi-static test research. Based on, 14 joint models featuring different RBS are devised to evaluate their influence on seismic behavior, such as joint failure mode, bending moment (M)-rotation angle (θ) curve, ductility, and energy consumption. The results indicate that when the flange and web are individually weakened, they alleviate to some extent the concentrated stress of the core module (CM) and column end steel skeleton in the joint core area, but both increase the stress on the flange connecting plate (FCP). At the same time, the impact of both on seismic performance such as bearing capacity, stiffness, and energy consumption is relatively small. When simultaneously weakening the flange and web of the steel beam, forming plastic hinges at the weakened position of the beam end, significantly alleviated the stress concentration of the CM and the damage at the FCP, improving the overall deformation and energy consumption capacity of joints. But as the weakening size of the web increases, the overall bearing capacity of the joint shows a decreasing trend.

• 핵의학기술
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• 제25권2호
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• pp.15-24
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• 2021

SPECT/CT는 보급 초기에 뛰어난 보정방법과 융합영상을 기반으로 한 정성적 기능이 주목받았고, 최근 동반진단치료(Theranostics)등의 도입으로 그 정량적 기능에 대한 관심과 활용이 증가되는 추세이다. PET/CT와 달리 SPECT/CT의 절대 정량화는 조준기의 종류, 검출기 회전과 같은 조건들이 영상획득과 재구성 방법 등에 까다로운 요소로 작용하고 있다. 따라서 본 연구에서는 SPECT/CT 촬영조건 중 투영상수와 투영상당 획득시간에 따른 총 획득시간(검사시간)의 증·감이 방사능농도 추정치에 미치는 영향을 알아보고자 한다. 부피 9,293 ml의 원통형 팬텀에 멸균수를 가득 채운 후 99mTcO4- 91.76 MBq를 희석하여 총 획득시간 600 sec(10 sec/frame × 120 frames, matrix size 128 × 128)의 조건으로 기준영상을 촬영하였고, 체적감도와 교정인자를 확인하였다. 기준영상을 중심으로 총 획득시간을 60(-90%), 150(-75%), 300(-50%), 450(-25%), 900(+50%), 1200(+100%) sec/frame으로 증·감시켜 비교영상을 획득하였고, 각 영상별 세부조건은 투영상당 획득시간(sec/frame)을 1.0, 2.5, 5.0, 7.5, 15.0, 20.0 sec/frame(투영상수 120frames 고정)로, 투영상수를 12, 30, 60, 90, 180, 240 frames(투영상당 획득시간 10 sec/frame 고정)로 설정하였다. 획득된 각 영상에서 관심체적을 통하여 측정한 계수를 바탕으로 정성적 평가로서 CNR(Contrast to Noise Ratio)의 변동률(%)을 확인하였고, 방사능농도 추정치의 변동률(%)을 통해서는 정량적 평가를 시행하였다. 이때 방사능농도 추정치(cps/ml)와 실제 방사능농도(Bq/ml)의 관계는 회복계수(RC_Recovery Coefficients)를 지표로 비교·분석하였다. 투영상수 변화에 따른 결과[CNR 변동률(%), 방사능농도 추정치 변동률(%), RC]는 총 획득시간 증감률(%) -90%에서 [-89.5%, +3.90%, 1.04], -75%에서 [-77.9%, +2.71%, 1.03], -50%에서 [-55.6%, +1.85%, 1.02], -25%에서 [-33.6%, +1.37%, 1.01], +50%에서 [+33.7%, +0.71%, 1.01], +100%에서 [+93.2%, +0.32%, 1.00]이었으며, 투영상당 획득시간 변화에 따른 결과는 총 획득시간 증감률(%)-90%에서 [-89.3%, -3.55%, 0.96], -75%에서 [-73.4%, -0.17%, 1.00], -50%에서 [-49.6%, -0.34%, 1.00], -25%에서 [-24.9%, 0.03%, 1.00], +50%에서 [+49.3%, -0.04%, 1.00], +100%에서 [+99.0%, +0.11%, 1.00]이었다. SPECT/CT에서 총 획득시간의 증·감에 따라 획득된 총 계수와 그에 따른 영상품질(CNR)은 비례하여 변화하는 양상을 보였지만, 절대 정량화를 통한 정량적 평가에서는 모든 실험조건에서 5% 미만(-3.55에서 +3.90%)의 변화를 보여 큰 영향을 받지 않고 정량적 정확성(RC 0.96에서 1.04)을 유지하였다. 검사시간의 증가보다는 단축을 우선하여 고려하였을 때 총 획득시간 감소는 정성적 기능에 있어서 기존에도 배제할 수 없었던 사항이지만 정량적 기능은 큰 손실 없이 적용 가능하여 임상적으로 실효성이 있다고 판단된다. 다만 총 획득시간의 증·감 시 동일한 검사시간이라면 투영상수의 변경보다는 투영상당 획득시간의 변경이 정성적, 정량적으로 조건변화에 따른 변동 폭이 적은 것으로 나타났다.