• Journal of Multimedia Information System
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• 제8권1호
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• pp.23-30
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• 2021

Palmprint has become a popular biometric modality; however, palmprint recognition has not been conducted in video media. Video palmprint recognition (VPR) has some advantages that are absent in image palmprint recognition. In VPR, the registration and recognition can be automatically implemented without users' manual manipulation. A good-quality image can be selected from the video frames or generated from the fusion of multiple video frames. VPR in contactless mode overcomes several problems caused by contact mode; however, contactless mode, especially mobile mode, encounters with several revere challenges. Double-line-single-point (DLSP) assisted placement technique can overcome the challenges as well as effectively reduce the localization error and computation complexity. This paper modifies DLSP technique to reduce the invalid area in the frames. In addition, the valid frames, in which users place their hands correctly, are selected according to finger gap judgement, and then some key frames, which have good quality, are selected from the valid frames as the gallery samples that are matched with the query samples for authentication decision. The VPR algorithm is conducted on the system designed and developed on mobile device.

• 대한전자공학회논문지
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• 제26권7호
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• pp.140-145
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• 1989

이 논문에서는 ASIC 칩의 설계도면에서 발생하는 임의의 모양을 갖는 영역에서의 효과적인 회로배치 방법인 SOAP (self-organization assisted placement) 를 제안한다. 자율조직이란 Kohonen[1]이 제안한 신경회로망의 학습방법으로 가까이 위치하고 있는 신경소자들이 물리적으로 유사한 외부입력에 민감하도록 소자에 연결된 시냅스 (synapse)의 가중치들을 조절하는 것이다. SOAP에서는 회로 블럭을 신경소자에 회로 블럭의 위치 (x, y좌표)를 해당 신경소자에 연결된 2개의 학습입력으로부터의 시냅스의 가중치 쌍으로 대응시킴으로써 임의의 영역에서의 좋은 회로 배치 결과를 얻을 수 있었다. 이 방법은 또한 입체 표면에서의 회로 배치에도 확장될 수 있다.

• Journal of Korean Neurosurgical Society
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• 제56권1호
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• pp.16-20
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• 2014

Objective : Two-dimensional fluoroscopy-based computerized navigation for the placement of pedicle screws offers the advantage of using stored patient-specific imaging data in providing real-time guidance during screw placement. The study aimed to describe the accuracy and reliability of a fluoroscopy-based navigation system for pedicle screw insertion. Methods : A total of 477 pedicle screws were inserted in the lower back of 96 consecutive patients between October 2007 and June 2012 using fluoroscopy-based computer-assisted surgery. The accuracy of screw placement was evaluated using a sophisticated computed tomography protocol. Results : Of the 477 pedicle screws, 461 (96.7%) were judged to be inserted correctly. Frank screw misplacement [16 screws (3.3%)] was observed in 15 patients. Of these, 8 were classified as minimally misplaced (${\leq}2mm$); 3, as moderately misplaced (2.1-4 mm); and 5, as severely misplaced (>4 mm). No complications, including nerve root injury, cerebrospinal fluid leakage, or internal organ injury, were observed in any of the patients. Conclusion : The accuracy of pedicle screw placement using a fluoroscopy-based computer navigation system was observed to be superior to that obtained with conventional techniques.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제24권3호
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• pp.273-278
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• 2021

Purpose: Percutaneous endoscopic gastrostomy (PEG) is a safe method to feed patients with feeding difficulty. This study aimed to compare the outcomes of conventional PEG and laparoscopic-assisted PEG (L-PEG) placement in high-risk pediatric patients. Methods: In our tertiary pediatric department, 90 PEG insertions were performed between 2014 and 2019. Children with severe thoracoabdominal deformity (TAD), previous abdominal surgery, ventriculoperitoneal (VP) shunt, and abdominal tumors were considered as high-risk patients. Age, sex, diagnosis, operative time, complications, and mortality were compared among patients who underwent conventional PEG placement (first group) and those who underwent L-PEG placement (second group). Results: We analyzed the outcomes of conventional PEG placement (first group, n=15; patients with severe TAD [n=7], abdominal tumor [n=6], and VP shunts [n=2]) and L-PEG placement (second group, n=10; patients with VP shunts [n=5], previous abdominal surgery [n=4], and severe TAD [n=1]). Regarding minor complications, 1 (6.6%) patient in the first group underwent unplanned PEG removal and 1 (10%) patient in the second group had peristomal granuloma. We observed three major complications: colon perforation (6.6%) in a patient with VP shunt, gastrocolic fistula (6.6%) in a patient with Fallot-tetralogy and severe TAD, and pneumoperitoneum (6.6%) caused by early tube dislodgement in an autistic patient with severe TAD. All the three complications occurred in the first group (20%). No major complications occurred in the second group. Conclusion: In high-risk patients, L-PEG may be safer than conventional PEG. Thus, L-PEG is recommended for high-risk patients.

• Journal of Korean Neurosurgical Society
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• 제48권1호
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• pp.53-58
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• 2010

Objective : The purpose of this study was to review the safety and durability of aneurysms treated with stent-assisted coiling of ruptured anterior communicating artery aneurysms with small parent vessels (< 2.0 mm). Methods : Retrospective review of all ruptured aneurysm treated with stent assisted endovascular coiling between March 2005 and March 2009 at our institution was conducted. We report 11 cases of the Neuroform stent placement into cerebral vessels measuring less than 2.0 mm in diameter (range, 1.3-1.9 mm) in anterior cerebral artery. Clinical follow-up ranged from 3 to 12 months and imaging follow-up was performed with cerebral angiography at 6 months and 12 months after discharge. Results : Complete occlusion was achieved in 10 patients, and a remnant neck was evident in one. No stent displacement or no dislodgement occurred during stent placement. There was no evidence of thromboembolic complication, arterial dissection and spasm during procedure. We performed follow-up angiography in all patients at 6 months and/or 12 months from the first procedure. The follow-up angiographic data showed successfully results except one in-stent stenosis case. All patients improved clinical performances except one patient with severe vasospasm who showed poor clinical condition initially. Conclusion : We have safely and successfully treated 11 vessels smaller than 2.0 mm in diameter with self-expanding stents with good short and intermediate term results. More clinical data with longer follow-ups are needed to establish the role of stent-assisted coiling in ruptured aneurysms with small parent vessels.

• Clinical Endoscopy
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• 제56권6호
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• pp.716-725
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• 2023

Endoscopic retrograde cholangiopancreatography (ERCP) in patients with surgically altered anatomy is technically challenging. For example, scope insertion, selective cannulation, and intended procedures, such as stone extraction or stent placement, can be difficult. Single-balloon enteroscopy (SBE)-assisted ERCP has been used to effectively and safely address these technical issues in clinical practice. However, the small working channel limits its therapeutic potential. To address this shortcoming, a short-type SBE (short SBE) with a working length of 152 cm and a channel of 3.2 mm diameter has recently been introduced. Short SBE facilitates the use of larger accessories to complete certain procedures, such as stone extraction or self-expandable metallic stent placement. Despite the development in the SBE endoscope, various steps have to be overcome to successfully perform such procedure. To improve success, the challenging factors of each procedure must be identified. At the same time, endoscopists need to be mindful of adverse events, such as perforation, which can arise due to adhesions specific to the surgically altered anatomy. This review discussed technical tips regarding SBE-assisted ERCP in patients with surgically altered anatomy to increase success and reduce the risk of adverse events associated with ERCP.

• Journal of Korean Neurosurgical Society
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• 제60권6호
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• pp.644-653
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• 2017

Objective : Paraclinoid aneurysms are a group of aneurysms arising at the distal internal carotid artery. Due to a high incidence of small, wide-necked aneurysms in this zone, it is often challenging to achieve complete occlusion when solely using detachable coils, thus stent placement is often required. In the present study, we aimed to investigate the effect of stent placement in endovascular treatment of paraclinoid aneurysms. Methods : Data of 98 paraclinoid aneurysms treated by endovascular approach in our center from August 2005 to June 2016 were retrospectively reviewed. They were divided into two groups : simple coiling and stent-assisted coiling. Differences in the recurrence and progressive occlusion between the two groups were mainly analyzed. The recurrence was defined as more than one grade worsening according to Raymond-Roy Classification or major recanalization that is large enough to permit retreatment in the follow-up study compared to the immediate post-operative results. Results : Complete occlusion was achieved immediately after endovascular treatment in eight out of 37 patients (21.6%) in the stent-assisted group and 18 out of 61 (29.5%) in the simple coiling group. In the follow-up imaging studies, the recurrence rate was lower in the stent-assisted group (one out of 37, 2.7%) compared to the simple coiling group (13 out of 61, 21.3%) (p=0.011). Multivariate logistic regression model showed lower recurrence rate in the stent-assisted group than the simple coiling group (odds ratio [OR] 0.051, 95% confidence interval [CI] 0.005-0.527). Furthermore there was also a significant difference in the rate of progressive occlusion between the stent-assisted group (16 out of 29 patients, 55.2%) and the simple coiling group (10 out of 43 patients, 23.3%) (p=0.006). The stent-assisted group also exhibited a higher rate of progressive occlusion than the simple coiling group in the multivariate logistic regression model (OR 3.208, 95% CI 1.106-9.302). Conclusion : Use of stents results in good prognosis not only by reducing the recurrence rate but also by increasing the rate of progressive occlusion in wide-necked paraclinoid aneurysms. Stent-assisted coil embolization can be an important treatment strategy for paraclinoid aneurysms when considering the superiority of long term outcome.

• Journal of Chest Surgery
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• 제54권4호
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• pp.266-278
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• 2021

Lobectomy is the standard treatment for early non-small cell lung cancer. Various surgical techniques for lobectomy have been developed, and minimally invasive thoracic surgery, such as video-assisted thoracic surgery or robot-assisted thoracic surgery, has been considered as an alternative to conventional open thoracotomy. The recently robotic lobectomy technique has developed since the first case series was published in 2002. Several studies have reported that robotic lobectomy has comparable oncologic and perioperative outcomes to those of video-assisted thoracic surgery lobectomy and open lobectomy. However, robotic lobectomy remains a challenge for surgeons because of the steep learning curve, reduced tactile sensation, difficulty in port placement, and challenges in cooperation between the surgeon and assistant. Many studies have reported on robotic lobectomy, but few have presented surgical techniques for robotic lobectomy. In this article, the surgical techniques and optimal performance of robotic lobectomy are described in detail for all 5 types of lobectomy for surgeons beginning with robotic lobectomy.

• Journal of Korean Dental Science
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• 제14권1호
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• pp.32-39
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• 2021

'Crossed occlusion' is the condition in which occlusal intercuspation is lost when several teeth on upper and lower jaw remain. This report describes a clinical case in which a patient had two upper-left posterior teeth and two lower-right posterior teeth; typically known as left-right crossed occlusion. Considering the patient's general condition and financial situation, the treatment plan included placement of two implants on each jaw against the remaining teeth using surgical guide. To find out the ideal position of implants, digital diagnostic wax-up was preceded by superimposing the cast and cone beam computed tomography image, which was aided with radiographic stents. The consequent surveyed implant bridge provided stable vertical stop for fabrication of the implant assisted removable partial dentures. The patient was satisfied with the functionality and esthetics of definitive prosthesis.

• 대한치과보철학회지
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• 제62권2호
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• pp.146-156
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• 2024

임플란트 보조 국소의치의 치료는 오래전부터 여러 형태로 시도되어 왔으며, 이 중 임플란트 서베이드 크라운 국소의치의 경우 점차 예지성을 얻고 있으며, 특히 경제적, 해부학적으로 불리한 부분 무치악 환자에게 한 가지 치료 방법이 될 수 있다. 이때 임플란트의 식립 위치는 치료 목적에 따라 전방 식립과 후방 식립으로 분류될 수 있는데, 이는 환자의 치조제, 잔존치 예후, 대합치 등 여러 상황을 고려하여 결정되어야 한다. 본 증례에서는 하악 Kennedy 1급 부분 무치악 환자에게 두 개의 임플란트 서베이드 크라운을 활용한 하악 임플란트 보조 국소의치를 통해 수복하였다. 본 환자에게 후방 식립이 어렵다는 점과 잔존치의 예후를 고려하여 임플란트를 잔존치에 근접한 부위에 두 개를 식립하는 것이 계획되었으며, 가이드 수술을 통해 계획한 위치, 각도, 깊이에 식립되었다. 고정성 보철물 제작 과정은 상악 무치악 치아 배열 과정과 병행하여 예지성을 높였고, 국소의치를 제작 시에는 임플란트가 최후방 지대치로서 과도한 하중이 가하지 않도록 기능 운동을 허용하는 형태로 디자인되고, 이차 인상 과정을 거쳐 제작되었다. 각 치료 과정을 계획한대로 진행하여 환자와 술자 모두 심미적, 기능적으로 만족스러운 결과를 얻었기에 이를 보고하는 바이다.