• 대한소아치과학회지
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• 제28권4호
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• pp.694-699
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• 2001

III급 부정교합은 유치열기나 혼합치열기에 이미 그 증상을 예측할 수 있을 뿐 아니라 많은 경우 그 증상의 악화를 예방할 수도 있다. III급 부정교합의 원인으로는 단순한 상하악 치아의 위치 이상에 의한 치아 치조성 혹은 기능성 III급 부정교합과 상악골과 하악골의 비정상적 성장발육에 의한 골격성 III급 부정교합으로 나누어 볼 수 있다. 특히 초기의 기능적 III급 부정교합 환자의 경우 방치되면 다양한 환경적 유전적 요소와 함께 골격성 부정교합으로 전이될 수 있고 많은 경우 악골의 비대칭적 성장에 원인이 될 수도 있다. 따라서 이러한 부정교합의 일차적 조기치료는 소아치과 치료영역에서 중요한 관심 분야라 할 수 있다. Inverted labial bow appliance는 통상적인 active plate의 장점과 activator와 같은 양악장치의 장점을 동시에 수용할 수 있는 장치로 상악치아의 개별적인 치아이동이 용이하고 동시에 기능적으로 전방 변위된 하악을 쉽게 정상위치 시킬 수 있는 장치이다. 특히 구호흡 등의 기질적 원인을 가지는 환자나 복잡한 양악장치를 착용하는데 어려움이 있는 협조도가 부족한 환자의 경우 효과적으로 사용할 수 있다. 이러한 장치를 이용하기 위해서는 골격성 III급 부정교합과의 정확한 감별진단이 선행되야 함은 물론이다. 본 증례는 기능성 III급 부정교합으로 진단된 7세 여아에서 Inverted labial bow appliance를 이용하여 전치부 반대교합을 해소한 경우로 치료결과는 상하악 전치부의 치아 치조성 이동에 의해 주로 이루어졌다.

• 한국해양공학회지
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• 제23권2호
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• pp.1-7
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• 2009

This paper presents a sliding mode controller based on Ackermann's formula and applies it to stabilizing a two-wheeled mobile inverted pendulum in equilibrium. The mobile inverted pendulum is a system with an inverted pendulum on a mobile cart. The dynamic modeling of the mobile inverted pendulum was established under the assumptions of a cart with no slip and a pendulum with only planar motion. The proposed sliding mode controller was based upon a class of nonlinear systems whose nonlinear part of the modeling can be linearly parameterized. The sliding surface was obtained in an explicit form using Ackermann's formula, and then a control law was designed from reachability conditions and made the sliding surface attractive to the equilibrium state of the mobile inverted pendulum. The proposed controller was implemented in a Microchip PIC16F877 micro-controller. The developed overall control system is described. The simulation and experimental results are presented to show the effectiveness of the modeling and controller.

• 한국기계가공학회지
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• 제20권2호
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• pp.107-119
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• 2021

The cross-flow turbine is one of the most famous and widely used hydraulic power systems for a long time. The cross-flow turbine is especially popular in many countries and remote regions where off-grided because of its many benefits such as low cost, high efficiency at low head, simple structure, and easy maintenance. However, most modern turbines, including the cross-flow turbine, are unsuitable for the ultra-low head situation, known as less than 3m water head or zero head with over 0.5m/s flow velocity. In this study, we demonstrated a 20kW class inverted-type cross-flow turbine's performance. First, we reevaluated our previous studies and introduced how to design the inverted-type cross-flow turbine. Secondly, we fabricated the 20kW class inverted-type cross-flow turbine for the performance test. And then, we designed a testbed and installed the turbine system in the demonstration facility. In the end, we compare the demonstration with its previous CFD results. The comparing result shows that both CFD and real model fitted on guide vane angle at 10 degrees. At the demonstration, we achieved 42% turbine efficiency at runner speed 125 RPM.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1262-1266
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• 2003

Fuzzy sliding mode controller for a class of uncertain nonlinear dynamical systems is proposed and analyzed. The controller's construction and its analysis involve sliding modes. The proposed controller consists of two components. Sliding mode component is employed to eliminate the effects of disturbances, while a fuzzy model component equipped with an adaptation mechanism reduces modeling uncertainties by approximating model uncertainties. To demonstrate its performance, the proposed control algorithm is applied to an inverted pendulum. The results show that both alleviation of chattering and performance are achieved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 B
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• pp.428-430
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• 1997

An LQG/LTR based gain scheduling control scheme for the two link inverted pendulum is presented. It is shown by simulation that the gain scheduling scheme based on the robust linear control theory still preserves the robust property of the linear control scheme and can be applied to control a class of nonlinear systems.

• 한국멀티미디어학회논문지
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• 제19권2호
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• pp.460-468
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• 2016

The teaching method of colleges and universities is traditionally lectures then professors has described orally in class and students has listened to accompanying with papers, mid-terms, and final exams. Jon Bergmann and Aaron Sams have developed new way of teaching called flipped learning; Classwork at home and homework in class. By adapting the method, this paper researched how efficient it is and what factors tutors should consider for better results. Specifically this research examined the flipped learning applying to basic 3D graphics class of J University in Korea and students answered surveys and took a couple of tests. Since the most students of the class did not have any background of 3D graphics, it was the first time for them to work with 3 dimensional space coordinate system. As a result, the research showed positive side of flipped learning like increasing peers' interest to the class and positive attitude about video lectures watched before coming to class.

• Korean Journal of Mathematics
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• 제23권1호
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• pp.93-114
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• 2015

The "flipped" or "inverted" classroom, in which students study lecture-type material at home and do their "homework" in the classroom, has been the subject of research, particularly in the area of student achievement. Yet Bishop and Verleger (2013) state the need for an underlying theory to the practice. The purpose of this paper is to explore "multidimensional teaching," the authors' extension of the two-dimensional "flipped" classroom concept in light of Cambourne's (1995) Conditions for Learning. One author's math class for pre-service teachers was taught in two styles, a more traditional lecture format and in the \inverted" format. Students in the "flipped" format achieved at a higher level. Moreover, students' open-ended comments reveal that Cambourne's Conditions for Learning were implicit to the teaching practice. The authors suggest that practitioners of this style of teaching should deliberately develop student-centered practices, such as those mentioned by Cambourne, in order to retain the power that this teaching style currently has.

• Computers and Concrete
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• 제31권6호
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• pp.469-484
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• 2023

The response mechanism of simply supported two-way reinforced concrete (RC) slabs under fire was numerically studied from the view of stress redistribution using the finite element software ABAQUS. Results show that: (1) Simply supported two-way RC slabs undergo intense stress redistribution, and their responses show four stages, namely elastic, elastic-plastic, plastic and tensile membrane stages. There is no cracking in the fire area of the slabs until the tensile membrane stage. (2) The inverted arch effect and tensile membrane effect improve the fire resistance of the two-way slabs. When the deflection is L/20, the slab is in an inverted arch effect state, and the slab still has a good deflection reserve. The deformation rate of the slab in the tensile membrane stage is smaller than that in the elastic-plastic and plastic stages. (3) Fire resistance of square slabs is better than that of rectangular slabs. Besides, increasing the reinforcement ratio or slab thickness improves the fire resistance of the slabs. However, an increase of cover thickness has little effect on the fire resistance of two-way slabs. (4) Compared with one-way slabs, the time for two-way slabs to enter the plastic and tensile cracking stage is postponed, and the deformation rate in the plastic and tensile cracking stage is also slowed down. (5) The simply supported two-way RC slabs can satisfy with the requirements of a class I fire resistance rating of 90 min without additional fire protection.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권8호
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• pp.467-472
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• 2000

A three-level decoupled sliding mode controller is developed to achieve asymptotic stability for a class of sixth-order nonlinear systems. The sixth-order system is decoupled into three subsystems according to the structure of the whole system. Each subsystem has a separate control target in the form of a sliding surface. The information of the third sliding surface is transferred to the second one through an intermediate variable and the information of the second sliding surface is transferred to the first one through another intermediate variable. Consequently, the controller designed on the basis of the first sliding surface can make three subsystems move toward their sliding surfaces, respectively. The three-level decoupled sliding mode controller is applied to the double-inverted pendulum problem where the zero stable states are required.

• 전기학회논문지
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• 제57권7호
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• pp.1247-1253
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• 2008

A design method of a T-S fuzzy model based reduced order nonlinear unknown input observer(NUIO) is presented. The fuzzy NUIO is designed based on the parallel distributed compensation(PDC) concept. It consists of a number of the linear UIOs, each of which is designed for each local linear model in the T-S fuzzy model of a class of nonlinear systems. The fuzzy NUIO provides not only the state estimates insensitive to the unknown inputs, for example, disturbances and faults etc., but also the estimates of the unknown inputs. Therefore, It can be employed in the state feedback control and disturbance rejection control of a class of nonlinear systems with unknown disturbances. It also applied to the robust residual generation for the fault detection and isolation systems and to the design of fault tolerant control systems. As an example, the NUIO is applied to an inverted pendulum system to show the state and disturbance estimation performance and to illustrate the fuzzy reduced order NUIO design method.