• 한국항공우주학회지
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• 제42권3호
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• pp.229-236
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• 2014

본 논문에서는 유도형 활공 탄약의 유도 법칙 및 제어기에 대해서 연구하였다. 기존의 유도형 탄약은 활공 없이 목표물을 타격하기 위한 유도 단계만 있지만, 유도형 활공 탄약은 사거리 증가를 위한 날개를 장착하고 활공하기 때문에 활공 유도 단계가 추가 되어야 한다. 본 논문에서는 벡터필드를 이용하여 탄약의 진입각을 만족시키기 위한 경로점까지 유도하였고, 종말 유도에서는 목표물 타격을 위해 비례항법유도 기법을 적용하였다. 또한 각 활공 영역별로 운동 모델을 선형화하고 각각에 맞는 제어기를 설계한 후, 선형 보간법을 이용하여 제어기의 이득 값을 계산한 뒤 제어에 사용하였다.

• Journal of Periodontal and Implant Science
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• 제32권3호
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• pp.475-488
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• 2002

The purpose of this study is to evaluate histologically the resorption and tissue response of various resorbable collagen membranes used for guided tissue regeneration and guided bone regeneration, using a subcutaneous model on the dorsal surface of the rat. In this study, 10 Sprague-Dawley male rats (mean BW 150gm) were used and the commercially available materials included acellular dermal matrix allograft, porcine collagen membrane, freeze-dried bovine dura mater. Animals were sacrificed at 2,6 and 8 weeks after implantation of various resorbable collagen membranes. Specimens were prepared with Hematoxylin-Eosin stain for light microscopic evaluation. The results of this study were as follows: 1. Resorption : Inner portion of porcine collagen membrane was resorbed a lot at 6 weeks, but its function was being kept for infiltration of another tissues were not observed. Freeze-dried bovine dura mater and acellular dermal allograft were rarely resorbed and kept their structure of outer portion for 8 weeks. 2. Inflammatory reactions : Inflammatory reaction was so mild and foreign body reaction didn't happen in all of resorbable collagen membranes, which showed their biocompatibility. 3. In all of resorbable collagen membranes, multinuclcated giant cells by foreign body reactions were not observed. Barrier membranes have to maintain their function for 4-6 weeks in guided tissue regeneration and at least 8 weeks in guided bone regeneration. According to present study, we can find all of the resorbable collagen membranes kept their function and structure for 8 weeks and were rarely resorbed. Foreign body reaction didn't happen and inflammatory reaction was so mild histologically. Therefore, all of collagen membranes used in this experiment were considered proper resorbable membranes for guided tissue regeneration and guided bone regeneration.

• 대한후두음성언어의학회지
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• 제8권2호
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• pp.204-209
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• 1997

In the treatment of spasmodic dysphonia, laryngeal injection of botulinum toxin has been reported to be successful. The treatment of adductor type spasmodic dysphonia with botulinum toxin type A injection using EMG was conducted in 24 patients and it's effect was compared with results from flexible nasopharyngoscopy guided injection(29 patients) and telelaryngoscopy guided injection(31 patients). Sixty two point five percent(62.5%) of patients using EMG and 75.8% of patients using flexible nasopharyngoscope and 90.0% of patients using telelaryngoscope reported that the patient's symptom was improved. The functional status of the patient's disorder was classified into low grades. The mean pre-injection grade for patients using EMG, flexible nasopharyngoscope and telelaryngoscope was 1.7, 1.6 and 2.1 respectively. And it was lowered to 1.0, 0.7 and 1.1 respectively after the injection. Results were similar(p＜0.05). As a self assessment method, patients were asked to rate their voice on a scale of 100. In this study, the mean pre-injection score was 66.3, 44.0 and 40.0 respectively. And it was improved to 74.8, 77.7 and 69.8 respectively after the injection. Among 23 patients who undergone above 3method, 17 patients(73.9%) told that EMG-guided botulinum injection was preferable method in its convenience and effectiveness. In conclusion, EMG guided botulinum toxin injection is an another effective method for the treatment of adductor type spasmodic dysphonia similar to telelaryngoscopy-guided injection and flexible nasopharyngoscopy guided injection.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제21권3호
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• pp.247-256
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• 2015

걸프전 이후 항공력은 전쟁 승리의 핵심 역할을 수행하였다. 하지만 레이저 유도폭탄, 전자광학 장비 같은 첨단무기들은 기상 조건이 맞지 않으면 그 효과가 크게 떨어진다. 따라서 레이저 유도폭탄이 할당된 항공기는 기상 악화 시 무장교체가 이루어져야 한다. 하지만 현재까지 무장교체 시기에 대한 객관적인 기준은 없다. 따라서 본 논문에서는 구름 영상을 처리하여 레이저 유도폭탄의 명중률을 예측하는 알고리즘을 제안한다. 알고리즘의 정확도를 검증하기 위해 레이저 유도폭탄에 영향을 미칠 수 있는 기상 상황을 모의 비행장비에 적용하고 모의 무장투하를 실시하여 데이터를 수집 및 분석하였다. 모의 비행장비에 적용한 기상 조건과 유사한 구름 영상을 제작하여 알고리즘에 적용한 결과 대부분의 기상 조건에서 레이저 유도폭탄의 명중률을 정확하게 예측할 수 있음을 확인하였다.

• The Korean Journal of Pain
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• 제33권3호
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• pp.258-266
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• 2020

Background: The genicular nerve block (GNB) is demonstrated from several reports to alleviate pain and improve knee functionality in patients with chronic knee osteoarthritis (OA). Ultrasound (US)-guided GNB has been the most used imaging method. This study aimed to compare the effectiveness of US-guided versus blind GNB in the treatment of knee OA. Methods: This prospective, randomized clinical trial included patients with knee OA based on American College of Rheumatology diagnostic criteria. The patients were evaluated for clinical and dynamometer parameters at the baseline, 4 weeks after treatment, and 12 weeks after treatment. The patients underwent blind injection or US-guided injection. Results: When compared with the baseline, both groups showed significant improvement in pain, physical function, and quality of life parameters. Significant differences were observed between the groups for clinical parameters (30-second chair stand test, 6-minute walk test) in favor of the US-guided group. On the other hand, blind injection was more significantly effective on some parameters of the Nottingham Health Profile. There wasn't any significant improvement in isokinetic muscle strength for either group. Conclusions: This study demonstrated that both US-guided and blind GNB, in the treatment of knee OA, were effective in reducing symptoms and improving physical function. GNB wasn't an effective treatment for isokinetic muscle function. US-guided injections may yield more effective clinical results than blind injections.

• 방송공학회논문지
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• 제23권2호
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• pp.283-292
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• 2018

LDR (low dynamic range) 영상에 비해서 밝기 범위가 크게 늘어난 HDR (high dynamic range) 영상을 촬영할 수 있는 장비와 디스플레이할 수 있는 기기들이 개발되고 있고 영상의 밝기 범위를 효율적으로 변환하는 방법에 대한 연구가 활발히 진행되고 있다. 본 논문에서는 LDR 영상을 HDR 영상으로 효율적으로 변환하기 위해서 guided filter를 사용한 reverse tone mapping 기법을 제안한다. Guided filter를 사용하여 한 장의 LDR 영상으로부터 BEF(brightness enhancement function)을 구한 후에 LDR 영상에서 밝기가 포화된 부분을 효율적으로 복원하여 HDR 영상을 생성하는 기법을 제안한다. 또한 영상이 지나치게 밝거나 어두운 경우 영상 촬영시의 노출 값을 추정하여 보정한 후에 밝기 범위를 변환하는 방법을 이용하여 생성되는 HDR 영상의 화질을 극대화하는 방법을 연구하고 모의 실험 결과로부터 제안하는 기법은 기존의 방법에 비해서 우수한 화질의 HDR 영상을 생성하는 것을 입증한다.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.749-765
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• 2010

There are on-going efforts to utilize guided waves for structural damage detection. Active sensing devices such as lead zirconate titanate (PZT) have been widely used for guided wave generation and sensing. In addition, there has been increasing interest in adopting wireless sensing to structural health monitoring (SHM) applications. One of major challenges in wireless SHM is to secure power necessary to operate the wireless sensors. However, because active sensing devices demand relatively high electric power compared to conventional passive sensors such as accelerometers and strain gauges, existing battery technologies may not be suitable for long-term operation of the active sensing devices. To tackle this problem, a new wireless power transmission paradigm has been developed in this study. The proposed technique wirelessly transmits power necessary for PZT-based guided wave generation using laser and optoelectronic devices. First, a desired waveform is generated and the intensity of the laser source is modulated accordingly using an electro-optic modulator (EOM). Next, the modulated laser is wirelessly transmitted to a photodiode connected to a PZT. Then, the photodiode converts the transmitted light into an electric signal and excites the PZT to generate guided waves on the structure where the PZT is attached to. Finally, the corresponding response from the sensing PZT is measured. The feasibility of the proposed method for wireless guided wave generation has been experimentally demonstrated.

• 한국시뮬레이션학회논문지
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• 제28권1호
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• pp.49-56
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• 2019

전산해석과 풍동시험을 이용하여 유도형 활공탄약의 공력특성을 연구하였다. 전산해석으로는 반실험적 기법인 Missile DATCOM과 전산유체역학 해석프로그램인 FLUENT를 사용하였다. 유도형 활공탄약에 대해 양력 및 항력, 피칭모멘트 등을 계산하여 기본적인 공력특성을 확인하였으며 기존의 탄약과는 전혀 다른 공력특성을 갖는 것을 확인했다. 전산해석을 통해 얻은 결과는 풍동시험을 통해 얻은 결과와 대체적으로 유사했다. 반실험적 기법으로 얻은 결과 중 피칭모멘트 값은 풍동시험결과와 약간 차이가 났지만, 전체적으로 전산해석의 결과는 시험결과와 유사한 경향과 값을 나타냈다. 본 연구를 통해 유도형 활공탄약의 공력특성을 확인하였으며, 유도형 활공탄약 초기설계 시 공력특성 분석을 위해 반실험적기법 및 전산유체역학적 해석 기법을 적용할 수 있음을 확인하였다.

• Smart Structures and Systems
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• 제29권2호
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• pp.301-309
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• 2022

Protective coatings are most widely used anticorrosive structures for steel structures. The corrosion under the coating damages the host material, but this damage is completely hidden. Therefore, a field-applicable under-coating-corrosion visualization method has been desired for a long time. Laser ultrasonic technology has been studied in various fields as an in situ nondestructive inspection method. In this study, a comparative analysis was carried out between a guided-wave ultrasonic propagation imager (UPI) and pulse-echo UPI, which have the potential to be used in the field of under-coating-corrosion management. Both guided-wave UPI and pulse-echo UPI were able to successfully visualize the corrosion. Regarding the field application, the guided-wave UPI performing Q-switch laser scanning and piezoelectric sensing by magnetic attachment exhibited advantages owing to the larger distance and incident angle in the laser measurement than those of the pulse-echo UPI. Regarding the corrosion visualization methods, the combination of adjacent wave subtraction and variable time window amplitude mapping (VTWAM) provided acceptable results for the guided-wave UPI, while VTWAM was sufficient for the pule-echo UPI. In addition, the capability of multiple sensing in a single channel of the guided-wave UPI could improve the field applicability as well as the relatively smaller size of the system. Thus, we propose a guided-wave UPI as a tool for under-coating-corrosion management.

• Clinical Endoscopy
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• 제56권1호
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• pp.100-106
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• 2023

Background/Aims: Endoscopic ultrasound (EUS) has become an essential diagnostic and therapeutic tool. EUS was introduced in 2013 in Indonesia and is considered relatively new. This study aimed to describe the current role of interventional EUS at our hospital as a part of the Indonesian tertiary health center experience. Methods: This retrospective study included all patients who underwent interventional EUS (n=94) at our center between January 2015 and December 2020. Patient characteristics, technical success, clinical success, and adverse events associated with each type of interventional EUS procedure were evaluated. Results: Altogether, 94 interventional EUS procedures were performed at our center between 2015 and 2020 including 75 cases of EUS-guided biliary drainage (EUS-BD), 14 cases of EUS-guided pancreatic fluid drainage, and 5 cases of EUS-guided celiac plexus neurolysis. The technical and clinical success rates of EUS-BD were 98.6% and 52%, respectively. The technical success rate was 100% for both EUS-guided pancreatic fluid drainage and EUS-guided celiac plexus neurolysis. The adverse event rates were 10.6% and 7.1% for EUS-BD and EUS-guided pancreatic fluid drainage, respectively. Conclusions: EUS is an effective and safe tool for the treatment of gastrointestinal and biliary diseases. It has a low rate of adverse events, even in developing countries.