• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2022년도 추계학술발표대회
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• pp.785-787
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• 2022

인공지능 로봇 산업의 발달로 우리의 일상생활 속 다양한 곳에서 활용되고 있다. 그러나 로봇의 고비용, 높은 진입 장벽의 문제로 상용화하기에 쉽지 않은 것은 사실이다. 따라서 본 논문에서는 기존 바리스타 로봇의 고비용, 높은 진입 장벽의 한계점을 해결하기 위해 저렴한 오픈소스 로봇인 elephant robotics사의 my cobot 280 pi와 Python을 통한 영상처리 기술을 접목하여 가성비 바리스타 로봇을 제작하고자 한다.

• Structural Engineering and Mechanics
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• 제89권6호
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• pp.549-556
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• 2024

A serial pendulum dynamic vibration absorber (DVA) was designed to suppress the vibration of two degrees of freedom (Two-DOF) structure model. The optimal DVA parameters are selected using a genetic algorithm (GA) by minimizing the fitness function formulated from the system's frequency response function (FRF). Two fitness function criteria, using one and two target frequency ranges, were utilized to calculate the optimal DVA parameters. The optimized serial pendulum DVA parameters were used to reduce structural vibration under free and forced excitation conditions. The simulation study found that the serial pendulum DVA can effectively reduce the vibration response for a small excitation amplitude. However, the DVA performance decreases for a large excitation amplitude due to the nonlinearity of pendulum motion, and the percentage of vibration response attenuation is smaller than that obtained using a small excitation amplitude.

• 대한조선학회논문집
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• 제46권5호
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• pp.527-535
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• 2009

This paper describes the control system to suppress the load pendulation using tagline for the floating crane. Dynamic equation of motion of the floating crane and the load is derived using Newton's 2nd law and free body model. The floating crane and the load are assumed that they move in center plane. Each rigid body has 3 DOF (surge, heave, pitch), because it moves in two directions and rotates. Then, this system, which is composed of two rigid bodies, has 6 DOF. The gravitational force, the hydrostatic force, the hydrodynamic force and the tension of the wire rope are considered as external forces, which affect to the floating crane. To suppress the pendulation of the load, the tagline, which connects between the load and the float crane, is applied to the system. The tagline is composed of the spring and the wire rope. Proportional and Derivative control is used as a linear control algorithm. The results of the numerical analysis of the 3,600 ton floating crane show that the tagline system is effective to suppress the load pendulation.

• 한국컴퓨터정보학회논문지
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• 제10권6호
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• pp.345-354
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• 2005

이동매니퓰레이터는 -이동로봇과 작업로봇이 직렬로 결합된 형태 - 작업 공간 밖에 존재하는 작업에 대하여 높은 성능으로 작업을 수행할 수 있으므로 고정 베이스 구조의 매니이퓰레이터에 비하여 다양한 작업 환경에서 유용하다. 임의의 위치에 있는 물체를 인식하기 위하여 이동매니퓰레이터에 부착된 2자유도의 능동카메라에 의해 입력되는 영상과 능동카메라의 기구학적 관계에 기초를 두는 직각좌표계를 이용하여 물체의 위치와 이동로봇의 위치를 구하는 방법을 제시한다. 동차행렬을 이용하여 이미지정보와 물체의 위치를 해석하므로 이동매니퓰레이터의 최적경로를 생성한다. 최종적으로, 물체의 인식을 통하여 작업로봇을 제어할 수 있는 조인트변수의 값을 계산한다. 제안된 방법은 제작된 이동매니퓰레이터로 시뮬레이션과 실험을 통하여 확인되어지고 논의된다.

• 전자공학회논문지C
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• 제36C권6호
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• pp.52-62
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• 1999

본 논문에서는 가상 환경에서 움직이는 인체 Avatar의 움직임을 인간의 가장 자연스러운 동작의 하나인 손 제스처를 이용하여 실시간으로 제어하는 인식 시스템의 구현에 관하여 상술한다. 동적 손 제스처는 컴퓨터와 제스처를 사용하는 사람과의 상호 연결 수단이다.가상공간 상에서의 자연스러운 움직임을 표현하기 위해 32개의 자유도(DOF)를 가진 인체 아바타를 구성하였으며, 정지, 전후좌우로 한 걸음 이동, 걷기, 달리기, 좌우로 회전, 뒤로 돌기, 물건 잡기의 동작 모드를 정의하여 가상공간 상의 인체 아바타는 미리 설정된 손 제스처에 따라 실시간에 따라 실시간으로 3차원공간상에서 움직일 수 있다. 실시간의 인체 아바타 이동에는 역 기구학과 기구학을 혼용하여 적용하였으며, 사이버 터치를 착용한 사용자의 손 제스처 인식에는 인공 신경망 이론과 퍼지 이론을 도입하여 실시간 인식이 가능하였다.

• Structural Engineering and Mechanics
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• 제15권1호
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• pp.83-114
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• 2003

A new simple 3-node triangular flat-shell element with standard nodal DOF (6 DOF per node) is proposed for the linear and geometrically nonlinear analysis of very thin to thick plate and shell structures. The formulation of element GT9 (Long and Xu 1994), a generalized conforming membrane element with rigid rotational freedoms, is employed as the membrane component of the new shell element. Both one-point reduced integration scheme and a corresponding stabilization matrix are adopted for avoiding membrane locking and hourglass phenomenon. The bending component of the new element comes from a new generalized conforming Kirchhoff-Mindlin plate element TSL-T9, which is derived in this paper based on semiLoof constrains and rational shear interpolation. Thus the convergence can be guaranteed and no shear locking will happen. Furthermore, a simple hybrid procedure is suggested to improve the stress solutions, and the Updated Lagrangian formulae are also established for the geometrically nonlinear problems. Numerical results with solutions, which are solved by some other recent element models and the models in the commercial finite element software ABAQUS, are presented. They show that the proposed element, denoted as GMST18, exhibits excellent and better performance for the analysis of thin-think plates and shells in both linear and geometrically nonlinear problems.

• 반도체디스플레이기술학회지
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• 제14권3호
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• pp.1-5
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• 2015

In photolithography process, resolution enhancement techniques such as optical proximity correction (OPC) and phase shift mask (PSM) have been applied to improve resolution. Especially, sub-resolution assist feature (SRAF) is one of the most important OPC to enhance image quality including depth of focus (DOF). However, imaging performance of the mask could be varied with the diffraction order amplitude changed by inserting SRAF. Therefore, in this study, we investigated the imaging properties and process margin of attenuated PSM with SRAF. Reflectivities of attenuated PSMs at 13.5 nm were 3, 6, 9% and simulation was performed by $PROLITH^{TM}$. As a result, aerial image properties and DOF as well as diffraction efficiency were improved by increasing the reflectivity of attenuated PSM. Additionally, printed critical dimension variations depending on SRAF width and space error were also reduced for attenuated PSM with high reflectivity. However, SRAF could be printed when reflectivity of attenuated PSM is high enough. In conclusion, optimization of reflectivity of attenuated PSM and SRAF to prevent side-lobe from being printed is needed to be considered.

• 플랜트 저널
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• 제17권3호
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• pp.42-46
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• 2021

드릴 스트링의 진동 문제는 수년간 드릴링 성능 저하의 주요 원인 중 하나로 인식되어 왔으며, 굴착 작업 시 발생하는 과도한 진동은 드릴링의 효율성, 파이프 피로, 비트의 수명 단축으로 인하여 고장을 초래할 수 있다. 이러한 진동의 원인은 드릴 스트링이 굴착 작업 중 궤적에 따라 파이프의 굽힘과 wellbore와의 접촉으로 인해 마찰이 발생하고 이러한 진동은 일반적으로 축 방향, 굴곡 및 비틀림 변형을 일으킨다. 본 연구에서는 Khulief와 Al-Naser가 제시한 모델을 바탕으로 드릴 스트링에 6자유도(DOF)의 구성요소를 갖는 모델을 적용하여 curved beam의 수치해석 값과 Analytical값을 비교하여 검증하고 드릴 스트링에 hookload와 WOB 경계조건을 주어 각 element 마다 동적 거동을 분석하였다. 실제 궤적을 적용하여 드릴 파이프의 굽힘이나 중력으로 인하여 Wellbore와 접촉되는 부분에 마찰을 적용하였고, 또한 마찰 작용 시 일정한 축 방향 속도를 유지하기 위한 PI제어 값을 설계하여 drillstring 전체의 각속도 변화와 실제 드릴 굴착 작업 중 발생하는 stick slip현상을 관찰하였다.

• Journal of Gastric Cancer
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• 제21권1호
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• pp.38-48
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• 2021

Purpose: As the number of gastric cancer survivors is increasing and their quality of life after surgery is being emphasized, single-port surgery is emerging as an alternative to conventional gastrectomy. A novel multi-degree-of-freedom (DOF) articulating device, the ArtiSential® device (LivsMed, Seongnam, Korea), was designed to allow more intuitive and meticulous control for surgeons facing ergonomic difficulties with conventional tools. In this study, we evaluated the feasibility of this new device during single-port laparoscopic distal gastrectomy (SP-LDG) for early gastric cancer (EGC) patients. Materials and Methods: Consecutive patients diagnosed with EGC who underwent SP-LDG with ArtiSential® (LivsMed) graspers between April 2018 and August 2020 were enrolled in the study. The clinical outcomes were compared with those of a control group, in which prebent graspers (Olympus Medical Systems Corp) were used for the same procedures. Results: Seventeen patients were enrolled in the ArtiSential® group. There was no significant difference in operative time (205.4±6.0 vs. 218.1±9.9 minutes, P= 0.270) or the quality of surgery, in terms of the number of retrieved lymph nodes (49.5±3.5 vs. 45.9±4.0, P=0.473), length of hospital stay (15.4±2.0 vs. 12.4±1.3 days, P=0.588), and postoperative complications (40.0% vs. 41.2%, P=0.595), between the ArtiSential® group and the control group. Conclusions: The new multi-DOF articulating grasper is feasible and can be used as an alternative for prebent graspers during SP-LDG.

• 대한간호학회지
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• 제51권6호
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• pp.732-745
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• 2021

Purpose: This study aimed to assess combined effects of early oral feeding after Cesarean section (C/S) under regional anesthesia on bowel function, gastrointestinal complications and surgical recovery. Methods: A systematic literature search was conducted using KISS, RISS, PubMed, CINAHL, EMBASE, CENTRAL and Google Scholar to identify randomized clinical trials comparing early oral feeding (EOF) with delayed oral feeding (DOF) after C/S. Outcome variables were bowel function and gastrointestinal complications and surgical recovery. Effect size was calculated using weighted mean differences (WMDs) and relative risks (RRs), with 95% confidence intervals (CIs). Results: Seven studies involving 1,911 patients from 568 studies, 7 studies were included in meta-analysis. EOF was significantly associated with shorter time to recover bowel movement compared with DOF (WMD, - 2.50; CI, - 3.50~- 1.50). EOF was not associated with nausea (RR, 1.15; CI, 0.87~1.53) and vomiting (RR, 0.96; CI, 0.65~1.42), but lower incidence of abdominal distension (RR, 0.70; CI, 0.50~0.98). EOF was significantly associated with shorter time to discontinuation of intravenous fluids (WMD, - 8.88; 95% CI, - 16.65~- 1.11) and removal of urinary catheter (WMD, - 15.23; CI, - 25.62~- 4.85). Conclusion: This meta-analysis provides evidence that EOF after C/S under regional anesthesia not only accelerates return of bowel function and surgical recovery but also reduces gastrointestinal complications. These results suggest that EOF should be offered to women who have undergone C/S to improve the recovery experience and reduce overall medical costs.