• 한국통신학회논문지
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• 제39B권1호
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• pp.17-28
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• 2014

스마트폰 사용자의 증가는 이동 통신사업자에게 커피숍, 지하철과 같은 공공장소에 와이파이 핫스팟을 제공함으로써 폭증하는 3/4G 트래픽을 분산시키는 노력을 하게 하였다. 전통적인 무선랜에서의 인증은 서비스 제공자측면에서 설계되었기 때문에, 서비스 이용자는 서비스 제공자에게 자신이 고객임을 증명하는 방식으로 이루어진다. 802.11 표준에서는 802.1X를 이용한 상호인증이 지원되지만, 서비스 이용자는 자신이 접속하려는 무선 AP가 정말 서비스제공자가 설치한 것인지 확인하는 것은 어렵다. 공격자는 사용자들의 개인 정보를 얻어내기 위하여 서비스 제공자가 설치한 AP와 동일한 SSID를 가진 위장 AP를 설치할 수 있다. 이 논문에서는 스마트폰 사용자 입장에서 정상적인 무선 AP를 인증하는 기법에 대해 소개한다. 그리고 이 논문의 제안이 이미 제공된 와이파이 핫스팟에서 보안 플러그인 형태로 잘 동작할 수 있음을 보이고, 이를 실험을 통해 증명한다.

• Journal of Korean Neurosurgical Society
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• 제51권3호
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• pp.135-140
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• 2012

Objective : To evaluate radiographic results of anterior fusion methods in two-level cervical disc disease : tricortical autograft and plate fixation (ACDF-AP), cage and plate fixation (ACDF-CP), stand-alone cage (ACDF-CA), and corpectomy and plate fixation (ACCF). Methods: The numbers of patients were 70 with a minimum 6 month follow-up (ACDF-AP : 12, ACDF-CP : 27, ACDF-CA : 15, and ACCF : 16). Dynamic simple X-ray and computed tomography were evaluated preoperatively, postoperatively, 6 month, and at the final follow-up. The fusion and subsidence rates at the final were determined, and global cervical lordosis (GCL), cervical range of motion, fused segment angle (FSA), and fused segment height (FSH) were analyzed. Results: Nonunion was observed in 4 (25%) patients with ACDF-CA, 1 (8%) patient with ACDF-AP, 1 (4%) patient with ACDF-CP. The number of loss of FSH (%) more than 3 mm were 2 patients (16%) in ACDF-AP, 3 patients (11%) in ACDF-CP, 5 patients (33%) in ACDF-CA, and 3 patients (20%) in ACCF. The GCL was decreased with ACDF-CA and increased with others. The FSA was increased with ACDF-AP, ACDF-CP, and ACCF, but ACDF-CA was decreased. At the final follow-up, the FSH was slightly decreased in ACDF-CP, ACDF-AP, and ACCF, but ACDF-CA was more decreased. Graft related complication were minimal. Screw loosening, plate fracture, cage subsidence and migration were not identified. Conclusion: ACDF-CP demonstrated a higher fusion rate and less minimal FSH loss than the other fusions in two-level cervical disc disease. The ACDF-AP and ACCF methods had a better outcome than the ACDF-CA with respect to GCL, FSA, and FSH.

• 한국운동역학회지
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• 제27권2호
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• pp.133-140
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• 2017

Objective: The purpose of this study was to determine the relationship between center of pressure (CoP) and local stability of the lower joints, which was calculated based on approximate entropy (ApEn) during walking in elderly women. Method: Eighteen elderly women were recruited (age: $66.4{\pm}1.2yrs$; mass: $55.4{\pm}8.3kg$; height: $1.56{\pm}0.04m$) for this study. Before collecting data, reflective marker triads composed of 3 non-collinear spheres were attached to the lateral surface of the thigh and shank near the mid-segment to measure motion of the thigh and shank segments. To measure foot motion, reflective markers were placed on the shoe at the heel, head of the fifth metatarsal, and lateral malleolus, and were also placed on the right anterior-superior iliac spine, left anterior-superior iliac spine, and sacrum to observe pelvic motion. During treadmill walking, kinematic data were recorded using 6 infrared cameras (Oqus 300, Qualisys, Sweden) with a 100 Hz sampling frequency and kinetic data were collected from a treadmill (Instrumented Treadmill, Bertec, USA) for 20 strides. From kinematic data, 3D angles of the lower extremity's joint were calculated using Cardan technique and then ApEn were computed for their angles to evaluate local stability. Range of CoP was determined from the kinetic data. Pearson product-moment and Spearman rank correlation coefficient were applied to find relationship between CoP and ApEn. The level of significance was determined at p<.05. Results: There was a negative linear correlation between CoP and ApEn of hip joint adduction-abduction motion (p<.05), but ApEn of other joint motion did not affect the CoP. Conclusion: It was conjectured that ApEn, local stability index, for adduction/abduction of the hip joint during walking could be useful as a fall predictor.

• 한국추진공학회지
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• 제21권4호
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• pp.21-27
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• 2017

본 논문에서는 HTPB/AP/Al계 추진제의 성능 개선을 위한 연소속도와 압력지수를 제어하기 위하여 연소특성에 관한 AP입자 사이즈 비율과 연소촉매로 사용된 Butacene 함량의 영향을 조사하였다. 23%의 $28{\mu}m$ Al과 3%의 Butacene을 포함하는 추진제 조성에서 연소속도와 압력지수는 $9{\mu}m$ AP 입자의 함량이 증가함에 따라 증가하였다. 그리고 Butacene을 함유하는 추진제는 비교적 낮은 압력지수 특성을 보임으로써 Butacene의 함량이 증가함에 따라 연소속도도 증가하였다. 그러나 Butacene의 함량에 의한 압력지수의 변화는 크게 나타나지 않았다.

• 한국정보통신학회논문지
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• 제25권1호
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• pp.36-43
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• 2021

본 논문에서는 제조 공장 내 AGV (Automated Guided Vehicle) 주행 중 객체 인식을 위한 YOLO v3 알고리즘의 정확도에 대해 살펴보았다. 실험을 위해 2D LiDAR 및 스테레오 카메라가 장착된 AGV를 준비하였다. AGV 주행 중 2D LiDAR를 활용한 SLAM 기법으로 지도 정보를 획득하였고 스테레오 카메라를 활용한 객체 인식이 이루어졌다. 그리고 YOLO v3 알고리즘 기반의 학습 정도에 따른 재현율, AP, mAP 등을 측정하였다. 실험 결과, 4000장의 train data 와 500장의 test data 로 훈련된 YOLO v3 알고리즘에 AGV에 장착된 스테레오 카메라의 시점과 높이에서 획득한 1200장의 이미지를 추가로 학습할 경우 mAP가 약 10% 향상되었다. 정밀도(precision) 와 재현율 역시 각각 6.8%와 16.4% 향상되었다.

• 대한본초학회지
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• 제37권4호
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• pp.1-8
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• 2022

Objectives : Dioscorea batas Decaisne (DB) has been known to be good for the digestive system on Eastern Asia. However, the protective effect of DB on acute pancreatitis (AP) has not been studied. In this study, we tried to investigate the protective effect of DB water extract on caerulein-induced AP. Methods : To measure the protective effect of DB on AP, Mice were injected with cholecystokinin analogue caerulein (50 ㎍/kg) hourly for 6 times. DB water extract (200 or 400 mg/kg) or saline (control group) was administered orally 1 h before the first injection of caerulein. The mice were sacrificed at 6 h after the last injection of caerulein. The pancreas tissues and serum samples were immediately taken for further analysis. Results : Administration of DB water extract showed the inhibitory effect on the increase of pancreas weight/body weight ratio, pancreatic histological damage. And the rise of serum lipase level was significantly reduced in DB water extract treatment group during AP in mice. However administration of DB water extract did not show significant reduction in serum amylase level. Also, mRNA levels of pro-inflammatory cytokines Interleukin (IL)-6 and Tumor necrosis factor (TNF)-𝛼 but not IL-1𝛽 were inhibited by administration of DB water extract. Conclusions : Taken together, we found that administration of DB water extract ameliorates the severity of caerulein-induced AP, which suggests the potential to be an effective treatment on AP.

• 한방재활의학과학회지
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• 제18권4호
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• pp.161-169
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• 2008

Objectives : This study was carried out to investigate the relationship of pelvic alignment between AP view of the pelvis in standing and supine position. Methods : Sixteen healthy peoples who get $51.59{\pm}4.14$ as average in SF-36 were evaluated by X-ray findings. After measuring innomiate measurement, off centering measurement, sacral ala measurement, illium shadow measurement, the area of obturator foramen, those were analyzed statistically. Results : It was not all to be corresponded to distort pelvic alignment of AP view of the pelvis in standing and in supine. Sometimes it was the opposite result. Conclusions : These results suggest that the diagnosis of pelvic alignment to go through on each position is brought about disagreement with each other.

• Restorative Dentistry and Endodontics
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• 제47권4호
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• pp.37.1-37.9
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• 2022

Objectives: This study aimed to evaluate the prevalence of apical periodontitis (AP) in the mesiobuccal roots of root canal-treated maxillary molars. Materials and Methods: One thousand cone-beam computed tomography images of the teeth were examined by 2 dental specialists in oral radiology and endodontics. The internal anatomy of the roots, Vertucci's classification, quality of root canal treatment, and presence of missed canals were evaluated; additionally, the correlation between these variables and AP was ascertained. Results: A total of 1,000 roots (692 first molars and 308 second molars) encompassing 1,549 canals were assessed, and the quality of the root canal filling in the majority (56.9%) of the canals was satisfactory. AP was observed in 54.4% of the teeth. A mesiolingual canal in the mesiobuccal root (MB2 canal) was observed in 54.9% of the images, and the majority (83.5%) of these canals were not filled. Significant associations were observed between the presence of an MB2 canal and the quality of the root canal filling and the presence of AP. Conclusions: AP was detected in more than half of the images. The MB2 canals were frequently missed or poorly filled.

• Journal of Yeungnam Medical Science
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• 제7권1호
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• pp.113-119
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• 1990

본 교실에서 18MeV 선형가속기를 이용한 방사선절제술에 대한 선량 측정 및 분석결과는 다음과 같았다. 1. 인체모형 팬텀을 이용한 실제 치료시 위치의 오차는 AP-LAT면과 AP-VERT면에서 0.4mm였고, AP-VERT $45^{\circ}$경사면에서는 1.0mm였다. 2. $2{\times}2mm$조사면에 대한 80% 등선량곡선의 면적비가 80%였다. 3. 선형가속기의 gantry회전과 couch회전에 대한 중심축의 정확도를 실시하여 직경 1.5mm의 성적을 얻었다. 4. 본 연구에서 얻은 측정치는 지금까지 보고된 가장 작은 오차의 보고에 근접함으로 본원의 방사선절제술이 입상이용에 적절함을 시사하였다.

• 분석과학
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• 제31권4호
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• pp.161-170
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• 2018

메스암페타민(methamphetamine, MA)과 암페타민(amphetamine, AP)은 전세계적으로 널리 퍼진합성 흥분제로 보건 및 사회 문제, 경제적 비용 발생 등의 다양한 문제를 일으킨다. 또한 이러한 마약은 중독 및 남용 가능성이 매우 높기 때문에 확산 방지를 위한 방안의 하나로 복용자의 생체시료에서 이들 마약을 검출하기 위한 분석법 개발이 필요하다. 따라서 본 연구에서는 액체크로마토그래피-질량분석법(liquid chromatography-tandem mass spectrometry, LC-MS/MS)를 이용하여 소변에서 MA와 4-하이드록시메스암페타민(4-hydroxymethamphetamine, 4HMA), AP, 4-하이드록시암페타민(4-hydroxyamphetamine, 4HA)을 동시에 분석할 수 있는 분석법을 개발하였고 유효성 평가를 수행하였다. 전처리 시간 단축을 위해 50000 g에서 3 min 동안 초고속원심분리 후 시료 희석 주입법을 이용하여 LC-MS/MS에 주입하였다. 분리관은 역상 C18 컬럼을 사용하였고, 정량분석을 위해 MRM (multiple reaction monitoring) 모드를 적용하였다. 가중계수 $1/x^2$에서 정량 범위는 MA는 10-2500 ng/mL, AP는 1.0-800 ng/mL, 4HA와 4HMA는 2.0-200 ng/mL로 설정하였고, 검량선의 직선성은 결정계수($r^2$)를 구하여 평가하였다. 초고속원심분리법의 효율성을 확인하기 위해 전처리 과정으로 시린지 필터(membrane-filtration)를 적용한 결과와 비교하였고, 그 결과 분석물질에 따라 6-15 % 성능이 우수한 것으로 나타났다. 일내(intra-day)와 일간(inter-day) 정밀도는 6.6 % 미만이었고, 정확도는 -14.9-11.3 % 였다. 최저정량한계(LLOQ)는 2.0 ng/mL (4HA 및 4HMA), 1.0 ng/mL (AP), 10 ng/mL (MA)로 확인되었다. 선택성, 검출한계, 희석무결성, 기질효과, 효율성, 안정성을 평가한 결과 만족스러운 측정값을 얻었다. 또한 개발된 분석법을 마약 복용자의 소변에 적용하여 분석법의 유용성을 확인하였다.