• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.52-63
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• 2008

The side collision reconstruction algorithm is developed using three dimensional car crash analysis. Medium size passenger car is modeled for finite element analysis. Total 24 side collision configurations, four different speed and six different angle, are set up for making side collision database. Deformation index and degree index are built up for each collision case. Deformation index is a kind of deformation estimate averaging displacement of side door of crashed car from finite element analysis result. Angle index is constructed measuring deformed angle of crashing car. There are two kinds of angle index, one is measured at driver's side and the other is measured at passenger's side. Also a collision analysis information in side of cars is used for giving a basis for scientific and practical reason in a reconstruction of the car accident. The analysis program, LS-DYNA3D is utilized for finite element analysis program for a collision analysis. Those database are used for side collision reconstruction. Side collision reconstruction algorithm is developed, and applied to find the collision conditions before the accident occurs. Three example collision cases are tried to check the effectiveness of the algorithm. Deformation index and angle index is extracted for the case from the analysis result. Deformation index is compared to the established database, and estimated collision speed and angle are introduced by interpolation function. Angle index is used to select a specific collision condition from the several available conditions. The collision condition found by reconstruction algorithm shows good match with original condition within 10% error for speed and angle. As a result, the calculation from the reconstruction of the situation is reproducing the situation well. The performance in this study can be used in many ways for practical field using deformation index and degree index. Other different collision situations may be set up for extending the scope of this study in the future.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.934-937
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• 2003

In this paper, authors use a stereo vision system based on the visual model of human and establish inexpensive method that recognizes moving distance using characteristic points around the robot. With the stereovision. the changes of the coordinate values of the characteristic points that are fixed around the robot are measured. Self-displacement and self-localization recognition system is proposed from coordination reconstruction with those changes. To evaluate the proposed system, several characteristic points that is made with a LED around the robot and two cheap USB PC cameras are used. The mobile robot measures the coordinate value of each characteristic point at its initial position. After moving, the robot measures the coordinate values of the characteristic points those are set at the initial position. The mobile robot compares the changes of these several coordinate values and converts transformation matrix from these coordinate changes. As a matrix of the amount and the direction of moving displacement of the mobile robot, the obtained transformation matrix represents self-displacement and self-localization by the environment.

• Journal of Conservation Science
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• v.32 no.4
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• pp.561-570
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• 2016

This research was a technical case study for the authentic restoration of the seven-storied Simgoksa stone pagoda after disassembly and reconstruction using three-dimensional image analysis. During disassembly and reconstruction, the pagoda's properties were analyzed in terms of the overall modification and displacement of the pagoda. Distortion was minimized by ensuring structural stability during the reconstruction process. Also, the original site of the pagoda was examined in order to utilize it fully during rebuilding. Before reconstruction of the pagoda, moss and lichen on the stone surfaces were removed by scientific surface cleaning. The foundation of the pagoda was reinforced with rammed earth than was similar to the original foundation using a mixture of soil and quicklime. The results are expected to provide valuable data for the reconstruction of other stone pagodas.

• Hip & pelvis
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• v.35 no.3
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• pp.183-192
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• 2023

Purpose: This study aims to determine which intertrochanteric (IT) hip fracture and patient characteristics predict the necessity for adjunct reduction aides prior to prep and drape aiming for a more efficient surgery. Materials and Methods: Institutional fracture registries from two academic medical centers from 2017-2022 were analyzed. Data on patient demographics, comorbidities, fracture patterns identified on radiographs including displacement of the lesser trochanter (LT), thin lateral wall (LW), reverse obliquity (RO), subtrochanteric extension (STE), and number of fracture parts were collected, and the need for additional aides following traction on fracture table were collected. Fractures were classified using the AO/OTA classification. Regression analyses identified significant risk factors for needing extra reduction aides. Results: Of the 166 patients included, the average age was 80.84±12.7 years and BMI was 24.37±5.3 kg/m². Univariate regression revealed increased irreducibility risk associated with RO (odds ratio [OR] 27.917, P≤0.001), LW (OR 24.882, P<0.001), and STE (OR 5.255, P=0.005). Multivariate analysis significantly correlated RO (OR 120.74, P<0.001) and thin LW (OR 131.14, P<0.001) with increased risk. However, STE (P=0.36) and LT displacement (P=0.77) weren't significant. Fracture types 2.2, 3.2, and 3.3 displayed elevated risk (P<0.001), while no other factors increased risk. Conclusion: Elderly patients with IT fractures with RO and/or thin LW are at higher risk of irreducibility, necessitating adjunct reduction aides. Other parameters showed no significant association, suggesting most fracture patterns can be achieved with traction manipulation alone.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.23.1-23.8
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• 2015

Background: The purpose of this study was to investigate the functional effects of temporalis myofascial flap after condylectomy, with or without disc removal, in elderly patients with anterior disc displacement (ADD) without reduction and an erosive condylar surface of the temporomandibular joint (TMJ). Methods: A total of 15 joints from 11 elderly patients (71-78 years old) were included. The patients had pain, mandibular dysfunction symptoms, and unilateral or bilateral ADD as well as an erosive condylar surface of the TMJ. All patients underwent temporalis myofascial flap reconstruction after condylectomy, with or without disc removal. If the maximal mouth opening (MMO) remained <35 mm after condylectomy, coronoidotomy was also performed. Self-assessed pain and mandibular function, including MMO and protrusive and lateral movements, were evaluated. Results: No patient experienced serious complications. Most measurements improved significantly after surgery compared to preoperatively. Most patients achieved nearly-normal mouth opening at 4 weeks after surgery. Although most patients felt discomfort during active postoperative physiotherapy, no patient reported serious pain during the follow-up period. Conclusion: Although nonsurgical therapy is often the first treatment choice for ADD without reduction of the TMJ, surgical intervention involving condylectomy and temporalis myofascial flap reconstruction may be a reasonable first option for elderly patients with an erosive condylar surface of the TMJ.

• Journal of Korean Orthopaedic Sports Medicine
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• v.6 no.2
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• pp.92-98
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• 2007

Purpose: We evaluated the clinical results of arthroscopic ACL reconstruction using quadrupled hamstring tendon with tibial remnant-preserving technique. Materials and Methods: Thirty-five cases were evaluated from Feb, 2003 to May, 2006. The average interval from injury to surgery was $2.6{\pm}1.6$ months. The cause of injury was mostly sports-related trauma. The average follow-up period was 17 months. Tibial remnant was preserved as much as possible and caution was taken not to damage the remnant during ACL reconstruction. Postoperative rehabilitation was the same as the usual rehabilitation method after ACL reconstruction, except for delaying motion for 2 weeks with an extension locking brace. Clinical evaluation was performed using ROM; Lachman test; pivot-shift test; anterior displacement measurement using KT-2000 arthrometer; Lysholm score and proprioception measured by single limb standing test. Results: There was no limitation of knee motion without contracture. The Lachman test and pivot-shift test were both negative. The side-to-side difference of anterior displacement measured using KT-2000 arthrometer was improved from 6.7 mm to 2.2 mm. The average Lysholm score improved from 81 to 96. The single limb standing test for proprioceptive evaluation showed no significant difference from a normal leg. Conclusion: ACL reconstruction with tibial remnant-preserving technique can preserve mechanoreceptors with prorioception and expect good functional recovery.

• Journal of the Korean Arthroscopy Society
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• v.12 no.2
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• pp.139-146
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• 2008

Purpose: The purpose of this study is to introduce the double bundle posterior cruciate ligament(PCL) reconstruction using Achilles allograft by the tibial inlay method and evaluate the clinical results of 11 cases who had PCL reconstruction using this method and were followed for more than 2 years after surgery. Materials and Methods: Our series consists of 11 cases of PCL reconstruction due to chronic posterior instability of knee and acute PCL rupture. The clinical results were assessed using the IKDC(International Knee Documentation Committee) scoring system, posterior stress radiographs and the maximum posterior displacement using a KT-1000TM arthrometer. Results: The average preoperative posterior displacement in 90 degree flexion stress radiograph was measured 13.4 mm and in 10 degree flexion the average posterior displacement using the KT-1000TM arthrometer was measured 11.4 mm. Postoperatively the 13.4 mm reduced to 4.4 mm and the 11.4 mm reduced to 3.9 mm. According to IKDC scoring system, 9 cases(81.8%) were satisfied. One case showed limitation of flexion with mild stiffness in the knee and another one case was not improved the posterior instability sufficiently and no complication of allograft was noticed. Conclusion: The double bundle PCL reconstruction using Achilles allograft by the tibial inlay method is a useful method for acute PCL rupture and chronic posterior instability of the knee including failed PCL reconstruction, because it will also make the posterior stability in the extension and 90 degree flexion position, and avoid the grafted tendon abrasion by acute turn of tibial tunnel.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.2 s.179
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• pp.164-171
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• 2006

Anterior cruciate ligament(ACL) injury of the knee is common and a serious ACL injury leads to ligament reconstruction surgery. Gait analysis is used to identify the result of surgery. The purpose of this study is to numerically evaluate and classify knee condition of patients through the chaos analysis. Experiments were carried out for 13 subjects (8 healthy subjects, 5 ACL deficient patients) walking on a treadmill. Sagittal kinematic data of the right lower extremity were collected by using a 3D motion analysis system. The recorded gait patterns were digitized and then coordinated by KWON3D. The largest Lyapunov exponent from the measured knee angular displacement time series was calculated to quantify local stability. It was found that the Lyapunov exponent becomes larger as the knee condition becomes worse. This study suggested a method of the severity of injury and the level of recovery. The proposed method discerns difference between healthy subjects and patients.

• Archives of Plastic Surgery
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• v.42 no.4
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• pp.424-430
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• 2015

Background Reconstruction of combined orbital floor and medial wall fractures with a comminuted inferomedial strut (IMS) is challenging and requires careful practice. We present our surgical strategy and postoperative outcomes. Methods We divided 74 patients who underwent the reconstruction of the orbital floor and medial wall concomitantly into a comminuted IMS group (41 patients) and non-comminuted IMS group (33 patients). In the comminuted IMS group, we first reconstructed the floor stably and then the medial wall by using separate implant pieces. In the non-comminuted IMS group, we reconstructed the floor and the medial wall with a single large implant. Results In the follow-up of 6 to 65 months, most patients with diplopia improved in the first-week except one, who eventually improved at 1 year. All patients with an EOM limitation improved during the first month of follow-up. Enophthalmos (displacement, 2 mm) was observed in two patients. The orbit volume measured on the CT scans was statistically significantly restored in both groups. No complications related to the surgery were observed. Conclusions We recommend the reconstruction of orbit walls in the comminuted IMS group by using the following surgical strategy: usage of multiple pieces of rigid implants instead of one large implant, sequential repair first of the floor and then of the medial wall, and a focus on the reconstruction of key areas. Our strategy of step-by-step reconstruction has the benefits of easy repair, less surgical trauma, and minimal stress to the surgeon.

• Archives of Plastic Surgery
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• v.37 no.6
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• pp.763-768
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• 2010

Purpose: Reconstruction of soft tissue defect using tissue expander can provide better flap which is more similar to surrounding tissue in color, skin texture and hair compared to other methods. Many pediatric patients need reconstruction of soft tissue defect because of giant congenital nevi, congenital or acquired malformations and burn scars. Reconstruction using tissue expander is adequate to minimize dysmorphism in these patients. We intended to assess outcomes of using tissue expander in pediatric patients by retrospective study. Methods: Total cases were 168 of pediatric patients who received soft tissue reconstruction using tissue expander by the same surgeon from February, 1982 to May, 2009. All patients who received soft tissue reconstruction were under 10 years old. Mean age was 4.3 years old, the youngest 13 months, the oldest 8 years. Eightynine cases were male and 79 cases were female. Most common cause was giant hairy nevi (67 cases, 39.9%), secondary cause was burn scar/scar contracture (61 cases, 36.3%). Trunk (38 cases, 22.6%) was most common anatomical location. Results: Soft tissue defects were successfully covered using tissue expander in 149 cases (88.7%) without major complications. There was infection on 8 cases (4.7%) and we treated by adequate antibiotics in these cases. There were tissue expander folding or valve displacement on 5 cases (3%). Conclusion: Usage of tissue expander is useful on pediatric patients because tissue expansion is rapid on children and there are less secondary contractures on operation site than full thickness skin graft. Because of psychological stress due to tissue expander, operation should be performed before school age.