• 한국시뮬레이션학회논문지
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• 제31권4호
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• pp.1-10
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• 2022

본 논문에서는 유도무기 성능분석을 위한 모듈화 기반 시뮬레이션 환경 개발에 관한 내용을 기술한다. 시뮬레이션 환경의 재사용성을 위하여 유도무기의 시뮬레이션 구성 요소들을 MATLAB Simulink를 기반으로 모듈화하였다. 그리고 시뮬레이션 인터페이스 및 모듈 관리를 위하여 Excel 및 MATLAB GUI 기반의 모듈 관리체계를 구현하였다. 또한 동일하지 않은 인터페이스로 설계된 모듈들을 통합하는 방안과 유도비행 시나리오 설계를 위해 유도/조종 단계를 구성하는 방안을 제시하였다. 최종적으로, 구현한 시뮬레이션 환경의 성능검증을 위하여 기존 시뮬레이션 결과와 비교하였다.

• 한국군사과학기술학회지
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• 제26권1호
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• pp.64-71
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• 2023

In the recent defence industries, it is required to develop the small and low cost embedded systems for guided missiles. According to the characteristics of guided missiles, the mission is conducted with multiple phases, which include a squib activation phase. By considering the unexpected squib activation, the squib system should be disabled after the launch of a guided missile. Therefore, the squib system needs to include the functions of the safe ignition and status check. This paper presents the squib ignition and status check circuits design for the compact embedded systems in guided missiles. Validation results show that for the functions of the squib ignition and status check, the presented circuits design performs well. The designed circuits also were implemented with various electronic devices and validated by the ground and flight tests.

• Smart Structures and Systems
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• 제33권1호
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• pp.41-53
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• 2024

Grouting sleeves are an essential connecting component of prefabricated components, and the quality of grouting has a significant influence on structural integrity and seismic performance. The embedded grouting sleeve (EGS)'s grouting defects are highly undetectable and random, and no effective monitoring method exists. This paper proposes an ultrasonic guided wave method and provides a set of guidelines for selecting the optimal frequency and suitable period for the EGS. The optimal frequency was determined by considering the group velocity, wave structure, and wave attenuation of the selected mode. Guided waves are prone to multi-modality, modal conversion, energy leakage, and dispersion in the EGS, which is a multi-layer structure. Therefore, a time-reversal (TR)-based multi-mode focusing and dispersion automatic compensation technology is introduced to eliminate the multi-mode phase difference in the EGS. First, the influence of defects on guided waves is analyzed according to the TR coefficient. Second, two major types of damage indicators, namely, the time domain and the wavelet packet energy, are constructed according to the influence method. The constructed wavelet packet energy indicator is more sensitive to the changes of defecting than the conventional time-domain similarity indicator. Both numerical and experimental results show that the proposed method is feasible and beneficial for the detection and quantitative estimation of the grouting defects of the EGS.

• Clinical Endoscopy
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• 제56권2호
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• pp.143-154
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• 2023

Advanced malignant hilar biliary obstruction (MHBO) with inaccessible papilla poses a significant challenge to endoscopists, as drainage of multiple liver segments may be warranted. Transpapillary drainage may not be feasible in patients with surgically altered anatomy, duodenal stenosis, prior duodenal self-expanding metal stent, and after initial transpapillary drainage, but require re-intervention for draining separated liver segments. Endoscopic ultrasound-guided biliary drainage (EUS-BD) and percutaneous trans-hepatic biliary drainage are the feasible options in this scenario. The major advantages of EUS-BD over percutaneous trans-hepatic biliary drainage include a reduction in patient discomfort and internal drainage away from the tumor, thus reducing the possibility of tissue or tumor ingrowth. With innovations, EUS-BD is helpful not only for bilateral communicating MHBO but also for non-communicating systems with bridging hilar stents or isolated right intra-hepatic duct drainage by hepatico-duodenostomy. EUS-guided multi-stent drainage with specially designed cannulas and guidewires has become a reality. A combined approach with endoscopic retrograde cholangiopancreatography for re-intervention, interventional radiology, and intraductal tumor ablative therapies has been reported. Stent migration and bile leakage can be minimized with proper stent selection and technique, and stent blocks can be managed with EUS-guided interventions in a majority of cases. Future comparative studies are required to establish the role of EUS-guided interventions in MHBO as rescue or primary therapy.

• Journal of Yeungnam Medical Science
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• 제41권3호
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• pp.179-187
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• 2024

Myofascial pain syndrome (MPS) is a common musculoskeletal disorder characterized by muscle pain, tenderness, and trigger points. Ultrasonography has emerged as a key tool for diagnosing and treating MPS owing to its ability to provide precise, minimally invasive guidance. This review discusses the use of ultrasonography in various approaches to evaluate and manage MPS. Studies have shown that shear-wave sonoelastography can effectively assess muscle elasticity and offer insights into trapezius stiffness in patients with MPS. Ultrasound-guided interfascial hydrodissection, especially with visual feedback, has demonstrated effectiveness in treating trapezius MPS. Similarly, ultrasound-guided rhomboid interfascial plane blocks and perimysium dissection for posterior shoulder MPS have significantly reduced pain and improved quality of life. The combination of extracorporeal shockwave therapy with ultrasound-guided lidocaine injections has been particularly successful in reducing pain and stiffness in trapezius MPS. Research regarding various guided injections, including dry needling, interfascial plane blocks, and fascial hydrodissection, emphasizes the importance of ultrasonography for accuracy and safety. Additionally, ultrasound-guided delivery of local anesthetics and steroids to the quadratus lumborum muscle has shown lasting pain relief over a 6-month period. Overall, these findings highlight the pivotal role of ultrasonography in the assessment and treatment of MPS.

• 한국임상수의학회지
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• 제21권2호
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• pp.181-183
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• 2004

Hepatic mass was aspirated under the guidance with ultrasound in 9-year old female maltese with signs of anorexia, hematochezia, vomiting, depression, and abdominal distension. Radiographic and abdominal ultrasonographic examinations were performed, which revealed enlarged tubular shaped uterine mass and solitary, small round hyperechoic hepatic mass dorsal to gall bladder as an incidental finding. Ultrasound-guided fine needle aspiration was completed, but histologic confirmation should be made for definitive diagnosis by tissue core or wedge biopsy.

• 산업기술연구
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• 제24권B호
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• pp.143-148
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• 2004

We present a fast algorithm for CDMA (code division multiple access) multiuser detection using the gradient guided search. The fast algorithm calculates the maximum likelihood (ML) metric so efficiently that it needs only O(K) additions in the presence of K users once some initialization is completed. The computational advantages of the fast algorithm over the conventional method are more noticeable as more iterations are required to obtain a suboptimal solution as in the initialization with matched filters.

• Clinical Endoscopy
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• 제55권6호
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• pp.819-823
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• 2022

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제30권1호
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• pp.17-24
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• 2004

The purpose of this study was to evaluate the stability and efficacy of biologic membrane made of freeze-dried cartilage as a barrier to facilitate guided bone regeneration in experimental non-healing bone defects in the rat mandible. Nine adult Sprague-Dawley rats (400-500g) were used in experiment. 5.0mm in diameter were created on the mandibular angle area by means of slow-speed trephine drill. In microscopic examination, dynamic immature bone forming at 2 weeks and its calcification at 4 weeks were observed. The membrane made of lyophilized cartilage taken from human costal cartilage seems to be very effective for guided bone regeneration as a biologic membrane and the scaffold for attachment of cells or local drug delivery system of growth factor, which may meet the ideal requirement of a barrier membrane and graft materials.

• 비파괴검사학회지
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• 제26권6호
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• pp.411-416
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• 2006

The critical subject of transverse crack detection in a rail head is treated in this paper. Conventional bulk wave ultrasonic techniques oftenfail because of shelling and other surface imperfections that shield the defects that lie below the shelling. A guided wave inspection technique is introduced here that can send ultrasonic energy along the rail under the shelling with a capability of finding the deleterious transverse crack defects. Dispersion curves are generated via a semi analytical finite element technique along with a hybrid guided wave finite element technique to explore the most suitable modes and frequencies for finding these defects. Sensor design and experimental feasibility experiments are also reported.