• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권3호
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• pp.117-122
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• 2014

Objectives: The purpose of this study was to evaluate the sinus bone graft resorption over 3 years after two-stage implant placement. Materials and Methods: The subjects for this study included 30 patients whose maxillary posterior ridges were too atrophic for implants. Bone-added osteotome sinus floor elevation was used in 15 maxillary sinuses, while the bone graft by lateral approach technique was used in 25 maxillary sinuses. The height from the top of the fixture to the sinus floor was estimated immediately after implant placement and the follow-up period was over 3 years. The surgery was classified with two groups: sinus bone grafting with and without autogenous bone. All implants were placed simultaneously. Results: The mean vertical bone loss was $3.15{\pm}2.95mm$. The survival rate of implants was 94.7%. Conclusion: The amount of bone resorption was not significantly associated with the surgical methods, the type of bone graft materials used, or sinus perforation during surgery.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.4967-4986
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• 2015

Multi-hop relaying communications have great potentials in improving transmission performance by deploying relay nodes. The benefit is critically dependent on the accuracy of the channel state information (CSI) of all the transmitting links. However, the CSI has to be estimated. In this paper, we investigate the channel estimation problem in one-way multi-hop MIMO amplify-and-forward (AF) relay system, where both the two-hop and three-hop communication link exist. Traditional point-to-point MIMO channel estimation methods will result in error propagation in estimating relay links, and separately tackling the channel estimation issue of each link will lose the gain as part of channel matrices involved in multiple communication links. In order to exploit all the available gains, we develop a novel channel estimation model by structuring different communication links using the PARAFAC and PARATUCK2 tensor analysis. Furthermore, a two-stage fitting algorithm is derived to estimate all the channel matrices involved in the communication process. In particular, essential uniqueness is further discussed. Simulation results demonstrate the advantage and effectiveness of the proposed channel estimator.

• Archives of Plastic Surgery
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• 제39권3호
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• pp.244-248
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• 2012

Many types of upper lip reconstruction have been introduced to treat defects after a tumor excision or trauma. The authors treated two cases of upper lip defects. A 35-year-old woman presented with a squamous cell carcinoma of the left upper lip that had invaded the corner of the mouth. After resecting the tumor, the defect was $3.7{\times}3.5cm$ in size. A 52-year-old woman presented with a dog bite of the right upper lip. The defect measured $4.0{\times}2.2cm$ in size. The two cases were reconstructed by combined rotation and advancement of a cheek flap. This technique produced a good functional outcome that allowed for oral competence and created an opening of adequate size. A combination of rotation and an advancement flap can be used to treat upper lip defects in a single-stage procedure. This approach produces a good functional and cosmetic outcome.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.895-904
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• 2021

This study aims to investigate the impact of innovation on firm efficiency. Panel data of fourteen finance companies and nine technology companies from 2011 to 2019 on the Vietnam Stock Exchange Market is derived from audited financial statements, annual reports, and other crucial reports that are provided by Vietstock; macroeconomic variables are collected from the World Bank Database. A two-stage approach is used. First, use of the Data Envelopment Analysis methodology to measure firm efficiency. Second, use of the Pooled ordinary least squares, the Fixed effects model, and the Random effects model to investigate the impact of innovation on firm efficiency. Furthermore, the Generalized Method of Moments and the Tobit model are used to validate the impact of innovation on firm efficiency, and the t-test is used to confirm the difference in efficiency with and without the impact of innovation between two industries. The results show that there is a significant impact of innovation on efficiency, and innovation plays a more important in increasing the efficiency of the finance industry than the technology industry. Moreover, the relation between age and efficiency is like the U-shaped, and between size and efficiency is like the inverted U-shaped, whereas efficiency is not associated with inflation.

• 한국전자파학회논문지
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• 제12권1호
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• pp.1-10
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• 2001

본 논문에서는 비동기 DS-CDMA 시스템의 성능 개선 기법으로서 다단 간섭제거기 (Multistage PIC)와 부분 다단 간섭제거기(Partial Multistage PIC)를 채용할 때 칩 동기 에러와 위상 에러가 위상 에러가 다중 접속간섭(MAI : Multiple Access Interference) 제거능력에 미치는 영향의 정도를 이론적으로 분석하고 이를 검증하기 위한 컴퓨터 시뮬레이션을 수행하였다. 성능 분석 결과로부터 동기가 완전한 경우에는 다단 간섭제거기와 부분 다단 간섭제거기 모두 큰 폭의 성능 개선을 이룰 수 있었는데 단(stage) 수를 증가시킬수록 다단 간섭제거기와 부분 다단간섭제거기의 성능 개선은 비슷하였다. 또한, 칩 동기 에러와 위상 에러기를 고려 할 경우, 1단(no cancellation)에서의 성능 열화가 각 단의 상관기 출력(decision statistic)에 영향을 줌으로써 다단 간섭제거기와 부분 다단 간섭제거기의 성능 개선을 감소시켰다. 그렇지만, 불완전 동기에도 불구하고 단(stage) 수를 증가시키면 두 간섭제거기 모두 강한 간섭제기능력을 보였다. 실제 시스템에서는 완벽한 칩 동기와 위상 동기 획득이 불가능하기 때문에 칩 동기 에러와 위상 에러에 대해서도 큰 폭의 성능 개선을 이룰 수 있고 구현상의 복잡도도 줄일 수 있는 간섭제거기가 필요하게 된다. 따라서 기존의 다단 간섭제거기와 거의 동일한 성능 개선을 달성하면서 구조가 간단하고 계산량이 적은 부분 다단 간섭제거기의 활용도가 높아질 것이 예상된다.

• 대한지리학회지
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• 제38권5호
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• pp.667-685
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• 2003

미국 캔자스주 정부와 연방정부가 필요로 하는 상세한 지표피복 수치지도제작을 위해, Landsat Thematic Mapper 자료를 이용하여 캔자스주 전체를 대상으로 43가지로 분류된 식생군단(vegetation alliance) 수준의 자연식 생지도를 제작하였다. 지도제작 방법으로는 봄, 여름, 가을의 계절별 위성자료를 이용하여 두 단계 분류절차를 거치는 이른바 '하이브리드(hybrid)' 방식을 채택하였다. 이 접근 방법은 첫 단계로 unsupervised classification을 이용, 자연녹지를 농경지로부터 분리해 낸 다음. 두 번째 단계에서 supervised classification, 현장확인조사. 그리고 분류 후 다양한 보강자료를 이용하여 최종적으로 자연식생을 구분ㆍ분류해 내는 것이다. 정확도 평가는 세 가지 분류 수준에서 실행되었는데, 이는 앤더슨 분류단계 I(Anderson level I), 식생군계(vegetation formation), 그리고 식생군단 수준을 포함한다. 확인결과 전반적인 정확도는 51.7%에서 89.4%에 이르는 것으로 조사되었다.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.229-232
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• 2005

In this paper, an image-based "approach-align -grasp" visual servo control design is proposed for the problem of object grasping, which is based on the binocular stand-alone system. The basic idea consists of considering a vision system as a specific sensor dedicated a task and included in a control servo loop, and we perform automatic grasping follows the classical approach of splitting the task into preparation and execution stages. During the execution stage, once the image-based control modeling is established, the control task can be performed automatically. The proposed visual servoing control scheme ensures the convergence of the image-features to desired trajectories by using the Jacobian matrix, which is proved by the Lyapunov stability theory. And we also stress the importance of projective invariant object/gripper alignment. The alignment between two solids in 3-D projective space can be represented with view-invariant, more precisely; it can be easily mapped into an image set-point without any knowledge about the camera parameters. The main feature of this method is that the accuracy associated with the task to be performed is not affected by discrepancies between the Euclidean setups at preparation and at task execution stages. Then according to the projective alignment, the set point can be computed. The robot gripper will move to the desired position with the image-based control law. In this paper we adopt a constant Jacobian online. Such method describe herein integrate vision system, robotics and automatic control to achieve its goal, it overcomes disadvantages of discrepancies between the different Euclidean setups and proposes control law in binocular-stand vision case. The experimental simulation shows that such image-based approach is effective in performing the precise alignment between the robot end-effector and the object.

• 한국강구조학회 논문집
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• 제23권3호
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• pp.327-335
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• 2011

본 연구의 목적은 강구조 비가새 골조의 열화특성에 영향을 미치는 구조적 인자들을 해석적인 방법으로 평가하고 설계 초기 단계에서 열화 현상을 근사적으로 평가할 수 있는 방안을 제안하는데 있다. 해석적 연구를 위해 arc length method를 적용한 2차원 2차 수정 소성힌지 해석법을 적용하였으며, 단층 단스팬 골조와 다층 단스팬, 다층 다스팬 골조에 대해 해석을 수행하였다. 해석의 주요 변수로는 축력비와 기둥 보의 강성변화를 적용하였다. 연구 결과 무차원 열화강성은 부재의 강성과 축력비에 모두 영향을 받는 것으로 나타났으나, 축력비가 열화강성에 주는 영향이 더욱 큰 것으로 나타났다. 이를 바탕으로 축력비를 변수로 한 열화 강성 평가식을 제안하였다.

• Smart Structures and Systems
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• 제20권2호
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• pp.175-180
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• 2017

The load-carrying capacity and structural behavior of concrete-filled steel tube (CFST) structures is highly influenced by the grouting compactness in the steel tube. Due to the invisibility of the grout in the steel tube, monitoring of the grouting progress in such a structure is still a challenge. This paper develops an active sensing approach with combined piezoceramic-based smart aggregates (SA) and piezoceramic patches to monitor the grouting compactness of CFST bridge structure. A small-scale steel specimen was designed and fabricated to simulate CFST bridge structure in this research. Before casting, four SAs and two piezoceramic patches were installed in the pre-determined locations of the specimen. In the active sensing approach, selected SAs were utilized as actuators to generate designed stress waves, which were detected by other SAs or piezoceramic patch sensors. Since concrete functions as a wave conduit, the stress wave response can be only detected when the wave path between the actuator and the sensor is filled with concrete. For the sake of monitoring the grouting progress, the steel tube specimen was grouted in four stages, and each stage held three days for cement drying. Experimental results show that the received sensor signals in time domain clearly indicate the change of the signal amplitude before and after the wave path is filled with concrete. Further, a wavelet packet-based energy index matrix (WPEIM) was developed to compute signal energy of the received signals. The computed signal energies of the sensors shown in the WPEIM demonstrate the feasibility of the proposed method in the monitoring of the grouting progress.

• 대한치과의사협회지
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• 제53권2호
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• pp.120-131
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• 2015

Objective: The purpose of this study is to compare the surgical treatment with conservative treatment and to evaluate the effectiveness of drug-holiday in bisphosphonate related osteonecrosis of the jaw (BRONJ) patients who were diagnosed as stage 2. Patients and Method: From January 2012 to October 2014, seventy-two patients who visit to Pusan National University of Dental Hospital were diagnosed as stage 2 of BRONJ. All the patients had taken computed tomography(CT) and panoramic radiography. The surgical treatment including sequestrectomy of necrotic bone and curettage of soft tissue around the sequestrum were performed to fifty patients. Twenty-two patients underwent conservative treatment such as antibiotics medications, mouth rinsing and follow up checking for every two weeks. Prognosis of treatment was classified into 3 groups - response, unresponse, and worsens - according to clinical, radiographic symptoms. P-value less than 0.05 were regarded as significant. Results: In surgery group, forty-five patients (90%) were healed without recurrence or any complication and five patients (10%) showed the wound dehiscence or infection. In conservative treatment group, fifteen patients (68.2%) were healed without any complication, four patients (18.2%) did not show improvement and three(4.2%) patients$^{\circ}{\emptyset}$ symptoms increased. P-value among groups was 0.014. Evaluation of preoperative drug-holiday in surgery group did not show the effectiveness(p=0.478). Conclusion: Statistically, the prognosis of patients with stage 2 BRONJ treated with surgery was significantly better than conservative treatment. There was no statistical difference for the preoperative drug-holiday.