• 음성과학
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• 제8권1호
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• pp.93-111
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• 2001

This study investigates the contribution of vocalic information following the release of an initial stop to the identification of the three-way stop contrast (aspirated, lax, and tense) in Korean. Recent studies showed that there is a strong interaction between consonant types and tone. The findings raise questions concerning Korean listeners' use of tonal (or vocalic F0) variation in differentiation initial tense, lax, and aspirated stops. The above issues are addressed in the present study using a cross-splicing methodology. The overall results show that low vocalic F0 provided the most salient information for lax stops; tense and aspirated stop identification depended on a combination of VOT, F0, and H1-H2 characteristics. The perceptual dominance of F0 over VOT for lax stops is consistent with the size of the F0 difference in utterance-initial position, as well as their prominent role in Korean intonational phonology.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제14권1호
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• pp.17-25
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• 2014

This paper presents the formulation of an impedance controller for regulating the contact force with the environment. To achieve an accurate force tracking control, uncertainties in both robot dynamics and the environment require to be addressed. As part of the framework of the proposed force tracking formulation, a neural network is introduced at the desired trajectory to compensate for all uncertainties in an on-line manner. Compensation at the input trajectory leads to a remarkable structural advantage in that no modifications of the internal force controllers are required. Minimizing the objective function of the training signal for a neural network satisfies the desired force tracking performance. A neural network actually compensates for uncertainties at the input trajectory level in an on-line fashion. Simulation results confirm the position and force tracking abilities of a robot manipulator.

• International Journal of Control, Automation, and Systems
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• 제6권1호
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• pp.76-85
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• 2008

Motivated by the fact that in many industrial robots the joint velocity is estimated from position measurements, the trajectory tracking of robot manipulators with output feedback is addressed in this paper. The fact that robot actuators have limited power is also taken into account. Let us notice that few solutions for the torque-bounded output feedback tracking control problem have been proposed. In this paper we contribute to this subject by presenting a theoretical reexamination of a known controller, by using the theory of singularly perturbed systems. Motivated by this analysis, a redesign of that controller is introduced. As another contribution, we present an experimental evaluation in a two degrees-of-freedom revolute-joint direct-drive robot, confirming the practical feasibility of the proposed approach.

• Journal of Korean Neurosurgical Society
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• 제39권4호
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• pp.296-299
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• 2006

A 35-year-old woman, previously treated for systemic metastases from retroperitoneal yolk sac tumor, presented with progressive painful paraparesis. Preoperative images showed severe cord compression by the metastatic infiltration of the lumbar vertebrae and epidural mass as well as a huge retroperitoneal mass. While performing unremarkable surgery in prone position, the patient abruptly fell into hypoxic insults and circulatory arrest. Intraoperative pulmonary tumor embolism was deemed a cause of death. When planning operative procedure for this dangerous malignancy, scrupulous manipulation is mandated and the possibility of fatal pulmonary tumor embolism should also be addressed and fully discussed preoperatively.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.24-24
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• 2019

This study investigates variations in the Western Pacific Subtropical High (WPSH) and its impact on South Korean precipitation in late summer during the period between 1958 and 2017. Composite analysis reveals that precipitation occurrence is directly linked to the displacement of the WPSH western ridge, a single, large-scale feature of the atmosphere in the Pacific Ocean. When WPSH ridging is located northwest (NW) of its climatological mean position, excessive precipitation is expected in late summer due to enhanced moisture transport. On the other hand, a precipitation deficit is frequently observed when the western ridge is located in the southeast (SE). Different phases of the WPSH are associated with lagged patterns of Pacific and Atlantic atmospheric and oceanic variability, introducing the potential to predict variability in the WPSH western ridge and its climate over northern East Asia by one month. Based on the identified SST patterns, a simple statistical model is developed and improvement in the ability to predict is confirmed through a cross-validation framework. Finally, the potential for further improvements in WPSH-based predictions is addressed.

• Clinical and Experimental Pediatrics
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• 제65권1호
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• pp.10-20
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• 2022

The prevalence of developmental disabilities is increasing worldwide over time. Developmental issues in infancy or early childhood may cause learning difficulties or behavioral problem in school age, further adversely affecting adolescent quality of life, which finally lead to low socioeconomic status in family, increase in medical expenses, and other relevant issues in various ways. Early childhood has brain plasticity, which means there is a high chance of recovering from developmental issues by early detection and timely intervention. Pediatricians are placed an ideal position to meet with young children till 6 years of age, of which age range is the time applicable to early intervention. Determining child's developmental status can be made by 2 pathways such as developmental surveillance and developmental screening tests. For better results, pediatricians should update their knowledge about developmental issues, risk factors, and screening techniques through varying educational program or other relevant educating materials. This paper will update reports on the prevalence of developmental disabilities and review the recent results of the Korean developmental screening test and discuss relevant issues. Finally, it will be addressed the pediatrician's role in early detecting developmental issues and timely intervention.

• 한국정밀공학회지
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• 제14권7호
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• pp.73-81
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• 1997

An new class of robust position/force hybrid control law is proposed for uncertain robot manipulators. The uncertainty is nonlinear and (plssibly fast) time-varying. Therefore, the uncertain factors such as imper- fect modeling, friction, payload change, and external disturbance are all addressed. Based on the possible bound of the uncertainty, the controller is constructed and the stability study based on Lyapunov function is presented. To show that the proposed control laws are indeed applicable, the theoretical result is applied to a SCARA-type robot manipulator and simulation result is presented.

• 대한예방한의학회지
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• 제19권3호
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• pp.77-90
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• 2015

Objective : The purpose of this study is to discuss the role and ways to improve the position and rights of Korean Medicine Doctors (KMDs) working at long-term care hospitals (LTCHs) through survey analysis. Method : (1) The legal and institutional position of KMDs is studied using current law and related papers. (2) The online survey was conducted through KMD community websites, targeted at KMDs working at LTCHs. Results : (1) Whereas there is perceived added benefit for the eight specializations for a specialist of Western medicine at LTCHs, in the case of a specialist of Korean Medicine, their value is not institutionally recognized at all. (2) A Western inpatient's medical fee is more than a Korean inpatient's medical fee, and the individual fee for the same medical treatment is also higher in Western hospitalization. So, Korean medical hospitalization actually cannot be made. Because of that, Korean Medicine Doctors find it difficult to be primary care physicians. (3) Musculoskeletal diseases and the aftereffects of cerebrovascular diseases were the most common chief complaints addressed in Korean medical consultations. Conclusion : This study shows that KMDs working at LTCHs have suffered many kinds of inequality. That is because of the limited medical scope of the current medical system and real constraints from the gap in Korean-Western medical fees by the National Health Insurance Corporation. Therefore, it is necessary to eliminate these variations along with revising the statute with continuous research.

• 항공우주시스템공학회지
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• 제14권2호
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• pp.1-11
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• 2020

Detecting obstacles and generating a suitable path to avoid obstacles in real time is a prime mission requirement for UAVs. In areas, close to buildings and people, detecting obstacles in the path and estimating its own position (egomotion) in GPS degraded/denied environments are usually addressed with vision-based Simultaneous Localization and Mapping (SLAM) techniques. This presents possibilities and challenges for the feasible path generation with constraints of vehicle dynamics in the configuration space. In this paper, a near real-time feasible path is shown to be generated in the ORB-SLAM framework using a chain-based path planning approach in a force field with dynamic constraints on path length and minimum turn radius. The chain-based path plan approach generates a set of nodes which moves in a force field that permits modifications of path rapidly in real time as the reward function changes. This is different from the usual approach of generating potentials in the entire search space around UAV, instead a set of connected waypoints in a simulated chain. The popular ORB-SLAM, suited for real time approach is used for building the map of the environment and UAV position and the UAV path is then generated continuously in the shortest time to navigate to the goal position. The principal contribution are (a) Chain-based path planning approach with built in obstacle avoidance in conjunction with ORB-SLAM for the first time, (b) Generation of path with minimum overheads and (c) Implementation in near real time.

• 한국항공우주학회지
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• 제37권10호
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• pp.1002-1009
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• 2009

본 논문에서는 저가의 스트랩다운 센서 및 탐색기 기반의 정밀한 유도필터 설계를 다룬다. 고려된 스트랩다운 센서는 3축의 가속도계와 자이로로 구성된 IMU, 3 축 자기장계 및 압력고도계이다. 유도탄의 위치, 속도, 자세 및 압력고도계의 바이어스 오차가 유도필터의 상태변수로 고려된다. 상태방정식 및 측정방정식의 비선형성이 크기 때문에 UKF(Unscented Kalman Filter)를 도입한다. 제안된 유도필터는 표적 위치오차가 없을 경우 항법필터로 동작한다. 표적오차가 존재하는 경우에도 유도탄-표적간 상대 정보를 정확히 추정함으로서 정밀한 유도성능을 보장한다. 특수한 교전상황에서는 유도필터의 가관측성 문제가 발생함이 확인되었다.