사족 보행 로봇의 관절고착고장을 위한내고장성 걸음새의 안정여유도에 관한 연구

양정민 대한전자공학회 2006 電子工學會論文誌-SC (System and control) Vol.43 No.5

Improvement in gait stability of fault-tolerant gaits for quadruped robots is addressed in this paper. The previously developed fault-tolerant gait gives a quadruped robot the ability to continue its walk against the occurrence of a leg failure. But it has a drawback of having marginal gait stability, which may lead to tumbling when the robot body's center of gravity is perturbed. To overcome such a drawback, a novel fault-tolerant gait is presented in this paper that generates positive stability margin against a locked joint failure, in which a joint of a leg is locked in a known place. Positive stability margin is obtained by adjusting foot positions of supporting legs between leg swing sequences. The advantages of the proposed fault-tolerant gait are discussed by comparing with the previous gait in terms of gait stability, stride length and gait velocity. 본 논문은 사족 보행 로봇에 대한 내고장성 걸음새의 안정여유도를 개선하는 방법을 논한다. 기존에 제안되었던 내고장성 걸음새는 사족 보행 로봇이 다리 고장이 발생한 후에도 보행을 계속할 수 있게 하였다. 하지만 내고장성 걸음새가 임계 안정여유도를 가지므로 몸체 무게중심의 위치가 순간적으로 바뀔 때에는 걸음새가 불안정해질 수 있다는 약점을 지니고 있다. 본 논문에서는 이러한 약점을 극복하기 위해서 양(陽)의 안정여유도를 가지는 내고장성 걸음새를 관절고착고장에 대해서 제안한다. 관절고착고장은 로봇 다리의 관절 하나가 한 지점에 고착되어 더 이상 움직일 수 없는 상태를 말한다. 양의 안정여유도는 걸음새 동작 과정에서 한 다리가 이동하기 전에 지지 다리들의 위치를 조정함으로써 얻어질 수 있다. 제안된 걸음새의 우수성을 입증하기 위해서 안정여유도, 보폭 등의 매개 변수들을 중심으로 기존 걸음새와 성능 비교를 수행한다.

비동기 순차 머신의 비-기본모드에서 발생하는고장 극복을 위한 교정 제어

양정민,곽성우 한국전기전자학회 2020 전기전자학회논문지 Vol.24 No.3

Fault tolerant corrective control for asynchronous sequential machines (ASMs) with transient faults is discussed inthis paper. The considered ASM is vulnerable to a kind of faults whose manifestation may arise during transienttransitions of the ASM, leading to transient faults occurring in non-fundamental mode. To overcome adverse effectscaused by these faults, we present a novel corrective control scheme that can detect and tolerate transient faults innon-fundamental mode. The existence condition and design algorithm for an appropriate fault tolerant controller isaddressed in the framework of corrective control theory. The applicability of the proposed control methodology isdemonstrated in the FPGA experiment. 본 논문은 과도 고장을 가지는 비동기 순차 머신에 대한 내고장성 교정 제어를 다룬다. 본 논문에서 다루는 고장은 머신이과도 상태 천이를 거칠 때 발현할 수 있으므로 비-기본 모드(non-fundamental mode)에서 원하지 않는 상태 천이를 일으킨다. 본 논문에서는 비동기 순차 머신의 비-기본 모드에서 발생하는 과도 고장을 탐지하고 극복할 수 있는 새로운 내고장성제어 시스템을 제안한다. 교정 제어 이론의 틀 안에서 내고장성 제어기의 존재 조건과 설계 과정을 제시한다. 또한 제안된제어 시스템의 효용성을 검증하기 위해 FPGA 실험을 실시한다.

조직확장술을 이용한 광범위한 두피 탈모의 재건

양정민,정재호,설정현 대한성형외과학회 2002 Archives of Plastic Surgery Vol.29 No.5

Tissue expansion has been used for several decades in plastic and reconstructive surgery. Recently tissue expansion of the hair bearing scalp provides an excellent surgical option for the treatment of wide alopecia.During the period 1990 to 2001, 34 patients, 37 cases of wide alopecia with various causes were treated using tissue expansion. Choice of the size, shape, and the numbers of the expander was done by a senior author. The capsule of the expanded tissue remained intact and transposition flaps were use to redistribute expanded scalp. For three patients, serial expansion was performed to completely remove the remaining alopecia. Another patients with male pattern baldness were also successfully treated using tissue expansion technique.In conclusion, tissue expansion for alopecia is a simple, safe, and reliable method and provides excellent aesthetic results. It is the treatment of choice for wide alopecia due to burn, tumor excision, traffic accident and even for male pattern baldness.

다리 궤적을 조정하는 육각 보행 로봇의 내고장성 걸음새

양정민,Yang Jung-Min 대한전자공학회 2005 電子工學會論文誌-SC (System and control) Vol.42 No.3

This paper proposes a novel fault-tolerant gait planning of a hexapod robot considering kinematic constraints. The failure concerned in this paper is a locked joint failure for which a joint in a leg cannot move and is locked in place. It is shown that the conventional fault-tolerant gait of a hexapod robot for forward walking on even terrain may be fallen into deadlock, depending on the configuration of the failed leg. For coping with such deadlock situation, a novel fault-tolerant gait planning is proposed. It can avoid deadlock by adjusting the position of the foot trajectory, and has the same leg sequence and stride length as those of the conventional fault-tolerant gait. To demonstrate the superiority of the proposed scheme, a case study is presented in which a hexapod robot, having walked over even terrain before a locked joint failure, could avoid deadlock and continue its walking by the proposed fault-tolerant gait planning. 본 논문에서는 기구학적 구속조건을 고려한 육각 보행 로봇의 새로운 내고장성 걸음새를 제안한다. 본 논문에서 고려하고 있는 고장은 관절고착고장으로 로봇 다리의 관절 하나가 어떤 위치에 고착되어서 보행이 끝날 때까지 움직일 수 없는 상태를 말한다. 본 논문에서는 먼저 육각 보행 로봇의 직선 보행을 위한 기존의 내고장성 걸음새가 고장 난 다리의 기구학적 구속조건에 따라서 교착 상태에 빠질 수도 있음을 해석적으로 증명한다. 그런 다음 이러한 교착 상태를 회피하기 위해서 새로운 내고장성 걸음새 계획을 제안한다. 제안하는 내고장성 걸음새는 다리의 궤적을 변경함으로써 고장 난 다리가 야기하는 교착 상태에서 벗어날 수 있으며, 기존 내고장성 걸음새의 다리 움직임 순서와 보폭을 그대로 유지한다. 제안한 걸음새 계획의 우수성을 입증하기 위해서 평탄 지형에서 정상적인 걸음새로 걷고 있는 육각 보행 로봇이 고장이 일어난 후 제안한 걸음새 계획을 이용하여 교착 상태에서 벗어나 내고장성 걸음새로 전이하는 사례 연구도 기술한다.

육각 보행 로봇의 내고장성 세다리 걸음새

양정민,노지명 대한전기학회 2003 전기학회논문지 D Vol.55 No.6

Fault-tolerance is an important design criterion for robotic systems operating in hazardous or remote environments. This paper addresses the issue of tolerating a locked joint failure in gait planning for hexapod walking machines which have symmetric structures and legs in the form of an articulated arm with three revolute joints. A locked joint failure is one for which a joint cannot move and is locked in place. If a failed joint is locked, the workspace of the resulting leg is constrained, but hexapod walking machines have the ability to continue static walking. A strategy of fault-tolerant tripod gait is proposed and, as a specific form, a periodic tripod gait is presented in which hexapod walking machines have the maximum stride length after a locked failure. The adjustment procedure from a normal gait to the proposed fault-tolerant gait is shown to demonstrate the applicability of the proposed scheme.

The Effect of Overtreatment at Medical Institutions on the Recovery and Satisfaction of Patients

양정민,김창훈,김재현 융합연구학회 2023 융합연구학회지 Vol.7 No.1

The purpose of this study was to analyze the effect of overtreatment of inpatients at medical institutions on recovery and satisfaction. In this study, 1,098 inpatients excluding missing values were analyzed using the 6th to 10th Korea Health Panel Survey (KHPS). To identify the relationship between overtreatment and recovery and satisfaction, the chi-square test and generalized estimation equation were used for the analysis. Compared to the group that answered ‘not at all’ about overtreatment, the negative recovery degree of the group that responded ‘very much so’ was 2.995 times higher (Odds Ratio [OR]: 2.995, 95% Confidence interval: 1.338 -6.705, P-value 0.008), and dissatisfaction was 35.272 times higher (OR: 35.272, 95% CI: 14.682-84.750, P-value <0.001). Furthermore, as a result of stratified analysis of the correlation between overtreatment and recovery and satisfaction according to whether the selection treatment was recommended, the group who responded ‘very yes’ to the overtreatment or not among the group who received the selection treatment recommendation was ‘not at all’ compared to the group that responded, their negative recovery rate was 5.553 times higher and the degree of dissat- isfaction was 271.375 times higher. Whereas, in the case of the group not recom- mended for elective treatment, the negative recovery rate was 2.775 times higher and the dissatisfaction rate was 26.656 times higher. As a result of the study, the higher the group with a stronger awareness of overtreatment, the higher the degree of patient dissatisfaction and discomfort, and a particularly strong correlation was found in the group recommended for selective treatment. Hence, if the institutional standards for providing appropriate medical care to the group experiencing excessive medical treatment through medical institutions and sufficient explanations about the medical services pro- vided to patients are provided, the satisfaction and recovery of patients will increase, and it is expected to be used as the basic data for preparing policy and institutional measures towards that end.

에너지 안정여유도를 이용한 사족 보행 로봇의 내고장성 걸음새

양정민 대한전기학회 2006 전기학회논문지 D Vol.55 No.7(D)

- This paper proposes a novel fault-tolerant gait for quadruped robots using energy stability margins. The previously developed fault-tolerant gaits for quadruped robots have a drawback of having marginal stability margin, which may lead to tumbling. In the process of tumbling, the potential energy of the center of gravity goes through a maximum. The larger the difference between the potential energy of the center of gravity of the initial position and that of this maximum, the less the robot tumbles. Hence this difference of potential energy, dubbed as Energy Stability Margin (ESM), can be regarded as the stability margin. In this paper, a novel fault-tolerant gait is presented which gives positive ESM to a quadruped robot suffering from a locked joint failure. Positive ESM is obtained by adjusting foot positions between leg swing sequences. The advantage of the proposed fault-tolerant gait is demonstrated in a case study where a quadruped robot with a failed leg walks on a even slope.

독거가구 및 기초생활수급 여부와 절주권고, 음주문제 상담 간의 연관성 분석

양정민,김하은,김재현 한국병원경영학회 2022 병원경영학회지 Vol.27 No.4

Purpose: The purpose of this study was to analyze the association between single-person households & Beneficiary of National Basic Livelihood and recommendation on alcohol consumption, and counseling on drinking problems for adults 19 years of age or older. Methods: In this study, excluding missing values, the association between the single-person household & Beneficiary of National Basic Livelihood and recommendation to refrain drinking alcohol, counseling for drinking problems was analyzed by using the chi-squre test and logistic regression analysis. Results: In the case of non-single person households, compared to single-person households, the recommendation rate to refrain drinking alcohol was 1.519 OR (Odds Ratio [OR]: 1.159 , p-value <.0001). meanwhile, in the case of Beneficiary of National Basic Livelihood, the recommendation rate to refrain alcohol consumption was higher by 1.414 OR (OR: 1.414, p-value: 0.011), and the drinking problem counseling rate was also higher by 2.257 OR (OR: 2.257, p-value: 0.026) compared to non-beneficiary group. Discussion & Conclusion: Based on the 2016-2019 National Health and Nutrition Survey, this study investigated the associaiton between single households & Beneficiary of National Basic Livelihood and recommendations to refrain alcohol, and counseling on drinking problems. Compared to the Beneficiary of National Basic Livelihood group, single-person household group has recently been classified as a socially vulnerable group, but it is not applicable in the policy category. If policy and institutional measures for treatment are provided, it is expected that the problem of alcohol abuse can be reduced.

비결정 모델에 대한 비동기 순차 회로의 교정 제어 I: 도달가능성 분석

양정민 대한전자공학회 2008 電子工學會論文誌-SC (System and control) Vol.45 No.4

The problem of controlling asynchronous sequential machines is addressed in this paper. Corrective control means to make behavior of an asynchronous sequential machine equal to that of a given model. The main objective is to develope a corrective controller, especially when a model is given as nondeterministic, or a set of reference models. The structure of corrective control system for asynchronous sequential machines is addressed first, followed by description of nondeterministic models. Then, we propose a method for analyzing reachability of asynchronous machines and nondeterministic models. Proposed methods are demonstrated in an example. 본 논문에서는 비동기 순차 머신의 교정 제어 문제를 다룬다. 교정 제어는 머신의 동작을 주어진 모델의 동작과 일치시키도록 하는 모델 매칭을 실현하는 제어를 말한다. 본 논문의 주요 목적은 비동기 순차 머신이 추종해야 하는 모델의 형태가 비결정적일 때, 즉 여러 개의 결정적 모델의 합으로 주어질 때 교정 제어기를 설계하는 일이다. 본 논문에서는 먼저 비동기 순차 머신을 위한 교정 제어 시스템의 형태와 동작 원리를 설명하고 비결정 모델의 표현 방법을 제안한다. 또한 교정 제어기 존재 조건을 표현하기 위해서 비동기 순차 머신과 비결정적 모델에 대한 도달가능성을 분석하고 예제를 통해서 분석 방법을 검증한다.

비평탄 지형 보행을 위한 내고장성 FTL 걸음새

양정민 대한전자공학회 2006 電子工學會論文誌-SC (System and control) Vol.43 No.3

In this paper, fault-tolerant gait planning of a hexapod robot for walking over irregular terrain is presented. The failure concerned in this paper is a locked joint failure for which a joint in a leg cannot move and is locked in place. Based on the previously proposed fault-tolerant tripod gait for walking over even terrain, fault-tolerant follow-the-leader(FTL) gaits are proposed for a hexapod robot with a failed leg to be able to walk over two-dimensional rough terrain, maintaining static stability and fault tolerance. The proposed FTL gait can have maximum stride length for a given foot position of a failed leg, and yields better ditch crossing ability than the previously developed gaits. The applicability of the proposed FTL gait is verified by using computer graphics simulations. 본 논문에서는 비평탄 지형을 보행하기 위한 육족 보행 로봇의 내고장성 걸음새 계획을 제안한다. 본 논문에서 고려하고 있는 고장은 관절고착고장으로 로봇 다리의 관절 하나가 어떤 위치에 고착되어서 보행이 끝날 때까지 움직일 수 없는 상태를 말한다. 기존에 제안되었던 평탄 지형 보행을 위한 내고장성 세다리 걸음새 계획을 바탕으로 본 논문에서는 육족 보행 로봇이 관절고착고장이 발생한 후에도 이차원 착지 불가능 영역이 존재하는 비평탄 지형을 걸을 수 있도록 하는 내고장성 FTL(Follow-The-Leader) 걸음새를 구현한다. 제안된 FTL 걸음새는 고장 난 다리의 착지점에서 로봇이 가질 수 있는 최대한의 보폭을 낼 수 있으며, 기존 내고장성 걸음새보다 착지 불가능 영역을 뛰어넘는 능력이 더 우수하다. 컴퓨터 시뮬레이션을 통해서 제안된 FTL 걸음새의 응용가능성을 검증한다.