논문 : 비물질적 표현특성을 이용한 미디어 벽체의 동적 회화 구성

고경진 ( Kyung Jin Ko ),이현수 ( Hyun Soo Lee ) 디자인융복합학회 2003 디자인융복합연구 Vol.2 No.1

비물질적 표현특성은 투명성, 일시성, 상호 관입성, 콜라주 등과 같은 표현특성으로 대표될 수 있다. 이러한 비물질적 표현특성은 정보화의 가속화에 따라 더욱 확산될 것으로 예상되며, 앞으로의 디자인 방향에 많은 영향을 미칠 것이다. 디자인 분야에 비물질적 표현특성을 보다 효과적으로 반영하기 위해서는 그 개념을 중문하게 이해하고 있어야 한다. 따라서, 본 논문에서는 비물질적 표현특성을 체계적으로 분석하고 분석의 결과를 바탕으로 미디어 스크린의 동적 회화 구성 방법을 제안하는데 연구의 목적을 두고 있다. 이를 위해 비물질적 표현특성을 크게 반영하고 있는 디자인 사례와 관련문헌을 이용하여 비물질적 표현특성을 도출해내고, 이를 표피적 특성, 공간적 특성, 매체적 특성 등의 세 가지로 나누어 설명한다. 그러고 이와 같은 비물질적 표현 특성을 반영한 미디어 스크린의 동적 회화 구성방법을 제안하고 있다. 미디어 스크린의 동적 회화 구성 방법을 보여 주기 위해 본 연구에서 사용하고 있는 사례는 몬드리안의 회화이다. 몬드리안의 회화를 사용한 이유는 회화의 구성 형태가 기하학적으로 구성되어 있기 때문에 회화의 구성에 대한 수정이 용이할 것이라고 생각하였기 때문이다. 이와 같은 미디어 스크린의 동적 회화 구성은 여러 분야에서 관림자의 심미적 욕구를 만족시키기 위해 활용될 수 있을 것이다. Dematerial Characteristics can be representative of many characteristics, such as Transparency, Simultaneity, Fluidity, Collage, etc... It is forecasted that these Dematerial Characteristics will be spreaded by the acceleration of the digital information wave. This study aims to interpret Dematerial Characteristics and develop methods for dynamic composition of painting in a media screen reflecting demateriality. In this study, Dematerial Characteristics are derived from building cases and related researches retlecting demateriality. And Dematerial Characteristics extracted from 6 papers related to demateriality are classified from the perspective of 3 types, such as surface characteristic, spacious characteristic and media characteristic. Dynamic composition of painting in a media screen means to transform an image in a media screen continuously or make a picture corresponding to a dweller`s requirements. This study describes 4 methods for dynamic composition of painting in a media screen. Those are methods for composition of painting by color changeability, transparency changeability, picture changeability, pattern changeability. To show Dynamic Composition of Painting in a media screen, this study has used Mondrian`s painting as a case. Because Mondrian`s painting is composed of geometrical composition. it is ease to modify composition of painting. As we know it, Dynamic Composition of Painting in a media screen can be applied to satisfy dweller`s aesthetic desires.

EXPERIMENTAL INVESTIGATION OF CHARACTERISTICS OF PRESSURE MODULATION IN A FUEL INJECTION SYSTEM

D. HUANG,M.-C. LAI 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.1

A piezoelectric atomization device achieves fuel pressure modulation through vibration of a piezoelectric pressure modulator. As a consequence, the fast alternating and slow moving streams collide with each other and further break up the fuel drop. In this paper, an experimental investigation was carried out to study the fluid dynamic characteristics of the spray atomization process of automotive port fuel injectors with a piezoelectric pressure modulator. The investigation mainly focuses on: (a) the coupling characteristics between the piezoelectric stack and the hydraulic as well as the transfer characteristics of pressure modulation from the piezoelectric modulator to the point above the orifice; (b) the time history of the pressure dynamic response at the point above the orifice under a typical modulation frequency, which reflects the variation of pressure modulation while the fuel injector is working; and (c) the time-variation characteristics related to mechanical structure and fluid dynamics. The experimental results expose some important dynamic characteristics of pressure modulation, which will be very significant and lead us to greatly improve the fuel injection system, optimize the control parameters and implement spray atomization with a high quality performance in the near future. A piezoelectric atomization device achieves fuel pressure modulation through vibration of a piezoelectric pressure modulator. As a consequence, the fast alternating and slow moving streams collide with each other and further break up the fuel drop. In this paper, an experimental investigation was carried out to study the fluid dynamic characteristics of the spray atomization process of automotive port fuel injectors with a piezoelectric pressure modulator. The investigation mainly focuses on: (a) the coupling characteristics between the piezoelectric stack and the hydraulic as well as the transfer characteristics of pressure modulation from the piezoelectric modulator to the point above the orifice; (b) the time history of the pressure dynamic response at the point above the orifice under a typical modulation frequency, which reflects the variation of pressure modulation while the fuel injector is working; and (c) the time-variation characteristics related to mechanical structure and fluid dynamics. The experimental results expose some important dynamic characteristics of pressure modulation, which will be very significant and lead us to greatly improve the fuel injection system, optimize the control parameters and implement spray atomization with a high quality performance in the near future.

Analysis of vorticity dynamics for hump characteristics of a pump turbine model

Deyou Li,Ruzhi Gong,Hongjie Wang,Lei Han,Xianzhu Wei,Daqing Qin 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.8

Conventional parameters based on CFD methodology for the investigation on hump characteristics of a pump turbine cannot reflect the dynamic interaction mechanism between the runner and the fluid. This research presents a dynamic interaction mechanism of a pump turbine operating in the hump region. First, vorticity dynamic parameters were obtained based on the theory of vorticity dynamics. Second, 3-D unsteady flow simulations were performed in a full pump turbine model using the SST k-ω turbulence model, and numerical results have a good agreement with the experiments. Then, analysis was carried out to determine the relation between the vorticity dynamic parameters and hump characteristics. The results indicate that the theory of vorticity dynamics has an advantage in evaluating the dynamic performance of a pump turbine. The energy transfer between the runner and the fluid is through vorticity dynamic parameterspressure and friction terms, in which the pressure term accounts for the most. Furthermore, vortex generation mainly results from the skin friction. Combining vorticity dynamic analysis with the method of Q-criterion indicates that hump characteristics are related to the reduction of the surface normal pressure work and vortex motion on the suction surfaces close to the leading edges in the runner, and the increase of skin friction work in the stay-guide vanes.

의료행위의 특질 재론

석희태 대한의료법학회 2024 의료법학 Vol.25 No.1

It has become a general idea today that the characteristics of medicine should be considered as a basis when discussing a medical personnel’s duty of care and whether or not it has been violated, and when discussing its duty of explanation and whether or not it has been fulfilled in medical practice. However, in the discussion of its characteristics, some shortcomings still exist, so the need for a re-discussion has been raised. Firstly, existing discussions on characteristics have failed to comprehensively grasp and explain the characteristics of medical practice. Secondly, in some researchers’ arguments, there are discrepancies between the terms used to express characteristics and their conceptual definitions or content. Thirdly, the lack of exemplified cases that reflect the characteristics of medicine - especially Supreme Court precedents - has led some to think negatively about the recognition and reflection of certain characteristics. In my early writings, I have described five characteristics of medical practice: ‘conflict in medical goals’, ‘initiating appropriate medical actions (progression of illness)’, ‘dynamics of medical intervention (diversity of symptoms)’, ‘diversity of medical effects’, ‘inherent risk of medical treatment (invasiveness)’. In this paper, keeping in mind the reasons for the need for reconsideration, I aim to analyze the characteristics of medicine in detail and cite key parts of representative Korean Supreme Court precedents that reflect each characteristic. The characteristics of medicine extracted from this paper are; There are ten factors, including the legitimacy of the essence of medical practice, timeliness of medical execution, dynamics of medical progress, diversity of medical effects, risk of medical invasion, non-uniformity of medical methods, limitations of medical capabilities, intervention of the medical subject, high degree of medical standards, and maldistribution of medical data.

Vibration characteristic analysis of gearbox based on dynamic excitation with eccentricity error

Wen Liu,Hang Zhao,Tengjiao Lin,Biao Gao,Yun Yang 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.11

In this study, the vibration characteristics of gearbox considering the eccentricity error and the friction excitation of helical gear pair were evaluated theoretically and experimentally. A geometric model of a single-stage helical gear pair with eccentricity error was established to obtain the calculation formula of the length of the dynamic contact line and the friction excitation. The multi-degree-of-freedom dynamic model of the transmission system was established considering the influences of tooth friction, support stiffness and damping, meshing stiffness and damping, static error, and dynamic tooth backlash. Then, the dynamic meshing forces of the system were obtained and applied to the gearbox for vibration response analysis using mode superposition method. A correlation test rig was developed to measure vibration under different operating conditions for verifying the correctness of the simulation models. Comparison between simulation and test was performed to demonstrate the accuracy of the proposed model in predicting vibrations. Results showed that eccentricity greatly influenced the overall vibration characteristics. The relative error between measurement and prediction can be significantly reduced by considering the eccentricity error in the dynamic model of transmission system.

Dynamic axial and radial temperature prediction of multi-plate frictional wet clutches in vehicle transmissions with the thermal resistance network method

Tianyan Liu,Xiangyang Xu,Minghui Zhang,Runbo Zhang,Yue Wu,Hongzhi Ji,Yanfang Liu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

Under the engaging process, excessive temperature of clutch plates may lead to thermal failure. Existing research has failed to find the hot spot and the radial temperature difference real-timely. They also neglected the influence of dynamic sliding process and hydraulic characteristics. Thus, a multi-domain dynamic model of the whole clutch was proposed, involving the mechanical dynamics, the hydraulic dynamics and thermics. With the thermal resistance network method, the real-time axial and radial temperature prediction of clutch plates was realized. The highest temperature occurs on the friction pairs of axial middle and the maximum value occurs on the radial 5th mass. Compared with the results by FEM, the deviation is about 6.5 %, but the time duration is reduced significantly. Furthermore, the influence of the outer hub vibration (160 Hz, 0.2 Hz) on the dynamic characteristics was discussed. This work was tested to be an effective and good basis for the health prediction of wet clutches.

Investigation on large turbo-generator stator end winding dynamic characteristics based on response surface method

Zhao, Yang,Xiao, Yang,Lu, Sheng,Sun, Hao,Huo, Wenhao,Liao, Yong The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.10

The natural frequencies corresponding to the particular mode shapes of a large turbo-generator must not be in the resonance region before delivery. Different parameters may clearly affect these dynamic characteristics. Different from other studies, this paper introduces a method for obtaining the inherent characteristics of end winding in a short period of time under multiple simultaneously changing parameters. The proposed process is based on the response surface method (RSM). In this method, the main concerned natural frequencies were taken as the critical index to describe the dynamic behaviors of the end winding, with which the mathematical relationship between the dynamic characteristics and design variables was analyzed. First, the stiffness of the rings, stiffness of the radial braces and number of pins bonded to the radial braces were used as samples for orthogonal experimental design. Then, the natural modes and frequencies of 25 different samples were acquired by conducting modal analysis with ABAQUS software. Utilizing these dynamic results, a second-order polynomial response surface model was established to describe the relationships between natural frequencies and these three different parameters. Then, the quality of this model was verified by calculating the valuating indexes for comparison with support vector regression (SVR). With the response surface model, the variation regularities of the natural frequencies and modes due to the above parameters were discussed. The method proposed in this paper can enable natural frequencies in the whole design space to be quickly determined without finite-element analysis, greatly improving the development efficiency and laying a foundation for dynamic response prediction during normal operation with different parameters and additional large turbo-generator stator end winding optimization.

전력계통 연계 풍력-터빈 발전기의 과도특성

서규석(Seo, Gyu-Seok),박지호(Park, Ji-Ho) 한국산학기술학회 2013 한국산학기술학회논문지 Vol.14 No.6

본 연구에서는 최근 각광받고 있는 풍력-터빈 발전기의 동적 특성에 관한 시뮬레이션을 수행한다. 풍력을 이용한 전기의 생산은 기존의 화력발전에 비해 환경에 악영향이 거의 없고 풍력자원 또한 무한하다고 할 수 있다. 즉, 풍력발전 자체는 많은 장점을 가지고 있다. 하지만 풍력-터빈 발전기가 기존의 전력계통에 연계되면 전력계통에 미치는 영향은 동기발전기만으로 구성된 전력계통과는 다르며 특히 동적특성이 달라진다. 따라서 안정적인 풍력발전 을 보장하기 위해서는 기존의 전력계통에 풍력발전기를 연계할 때 그 특성을 검토하는 것이 필수적이다. 본 논문에 서는 PSS/E를 이용하여 GE1.5MW의 풍력-터빈 발전기에 대한 동적특성을 시뮬레이션 한다. 풍속의 변화, 부하의 변 화 그리고 무한대 모선의 전압변화를 통하여 GE1.5MW의 풍력-터빈 발전기의 특성을 검토하였다. In this paper, a simulation study on dynamic characteristics of wind turbine generators is performed. The generation of electricity using wind turbines is being recently spotlighted as a renewable way. The wind is an infinite primary energy source. Further, other environmental impacts of wind power are limited as well. Therefore, the wind turbine generation itself has many advantages. However, when generators using wind turbines are connected to the conventional power system, the impact of the power system is different from that of the power system that consists of only synchronous generators, especially in dynamic characteristics. Therefore, it is essential to examine the characteristics of wind turbines in order to ensure reliable wind turbine generation in the power system containing wind turbine generators. In this paper, the dynamic characteristics of GE1.5MW wind turbine are simulated by using PSS/E. In the simulation of GE1.5MW wind turbine, wind speed variation, load change and voltage deviation of infinite bus are considered.

Dynamic Characteristics Simulation for a Simplex Swirl Injector

박홍복(Hongbok Park) 한국항공우주학회 2006 韓國航空宇宙學會誌 Vol.34 No.9

스월 인젝터의 비선형 동적특성을 모사할 수 있는 수치해석 모델을 개발하여 인젝터내의 정적/동적 특성을 분석하였다. Boundary Element Methods (BEMs)을 적용한 수치모델은 유체 경계면 산출에 매우 유리한 장점이 있어 표면의 불안정성 해석에 유용하게 적용되어 왔다. 이전의 연구 결과에서는 스월효과를 고려할 수 있도록 확장된 수치모델을 이용하여 인젝터의 형상을 고려한 정적특성을 보여주었다. 본 논문에서는 유입 흐름에 교란이 발생했을 때 인젝터의 각 구성요소에서의 동적응답을 분석하였고, 이론적 결과와 비교하여 수치모델에 대한 타당성을 검증하였다. 본 수치해석 결과는 입력류에서의 교란이 각 인젝터 구성품을 지나면서 감쇠/증폭되고 위상차를 만들게 되는 과정을 잘 모사하고 있다. 개발된 수치모델은 인젝터의 다양한 설계변수들이 유동특성에 미치는 효과 분석과 이론적 모델로는 예측이 어려운 비선형 영역에서의 동적 응답특성 분석에 유용하게 적용될 수 있을 것이다. A fully nonlinear model accounting for swirling effect has been applied in analyzing the dynamic response for a classical swirl injector. The current work applied highly accurate Boundary Element Methods (BEMs) in assessing its static and dynamic characteristics. On the basis of moving surface treatment method and surface instability study, which are obtained from the previous static characteristics analysis in pressure-swirl injectors, this work was expanded for analyzing the dynamics of a classical swirl injector. The dynamic response through injector components for disturbed inflow condition was investigated. The modified code was validated from comparison with the theoretical result for a typical swirl injector. Clearly the simulated result shows the interesting characteristics of swirl injectors to provide either amplification or damping of the input disturbance through each component. These results give promise in applying the current model to nonlinear dynamic characteristics of swirl injectors.

위치결정 스테이지에 대한 동적 모델링과 입력성형 제어

박상원(S. W. Park),홍성욱(S. W. Hong),최훈석(H. S. Choi),장준원(J. W. Jang) 한국생산제조학회 2008 한국생산제조학회지 Vol.17 No.2

This paper presents the dynamic analysis and input shaping control of a positioning stage. Vibration characteristics of the positioning stage are affected not only by the structural dynamics but also by the servo actuators that consist of the mechanism; driving motor and controller. This paper proposes an integrated dynamic model to accommodate both the structural dynamics and the servo actuators. Theoretical modal analysis with a commercial finite element code is carried out to investigate the dynamic characteristics of the experimental positioning stage. Experiments are performed to validate the theoretical modal analysis and estimate the equivalent stiffness due to the servo actuators. This paper deals with an input shaping scheme to suppress vibration of the positioning stage. Input shapers are systematically implemented for the positioning stage in consideration of its dynamics. The effects of servo control gain are also investigated. The experiments show that input shaping effectively removes residual vibrations and then improves the performance of positioning stage.