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.

Effect of clearances in rolling element bearings on their dynamic performance, quality and operating life

Mostafa Yakout,M. G. A. Nassef,Soheir Backar 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.5

The performance of rolling element bearings is one of the machine quality measures in industry. The fatigue life and performance of rolling element bearings depends mainly on the dynamic characteristics of those bearings. This paper studied the effect of the internal radial clearance on the damping characteristics, natural modes of vibration, and fatigue life of rolling element bearings. Vibration modal analysis was performed on rolling bearings of the same size and type to measure their dynamic characteristics. These dynamic characteristics include the natural frequency of the first mode of vibration, damping, and amplitude of frequency response function at resonance. The internal radial clearances of these bearings were measured. A statistical analysis was performed to study the correlation between the internal radial clearance and the dynamic characteristics of rolling bearings. It was found that the damping ratio of the bearing assembly increased by reducing the internal radial clearance of the bearing. Similarly, rolling bearings that have large internal clearances showed short predicted fatigue life. It is concluded that the dynamic characteristics, and consequently the dynamic performance, of rolling bearings are significantly affected by the internal radial clearance.

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.

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.

젠더특성에 따라 조직문화가 동적역량을 매개로 조직유효성에 미치는 영향

곽효근 ( Kwag Hyo Keun ),서철승 ( Seo Cheol Seung ),이상진 ( Lee Sang Jin ) 한국경영공학회 2019 한국경영공학회지 Vol.24 No.1

Many companies attempt to transform themselves into creative organizations to create high performance. Organizational culture and dynamic capabilities are essential to make a creative organization. As the participation of women in society is more prevalent than ever, enterprises should have more concern on creating an environment that maximizes the capability of women as a way of improving the business performance. The purpose of this study is to verify the mediating effect of dynamic capabilities that affects creativity for the organizational culture to influence organizational effectiveness in a rapidly changing environment, the fourth Industrial Revolution. Furthermore, this research investigates differences in organizational culture and dynamic capabilities according to gender characteristics. The result of this research is as followings. Rational culture affected to organizational effectiveness, however, Hierarchical culture affected only to creativity as a sub-factor of organizational effectiveness. Absorptive transformation capabilities as a sub-factor of dynamic capabilities mediated organizational culture and organizational effectiveness. And absorptive transformation capabilities positively affected to the organizational effectiveness in hierarchical culture as well. Rational culture positively affected to both dynamic capabilities and organizational effectiveness regardless of gender. In the rational culture, women are more involved to their job than men, and their performance is more than twice as high. Hierarchical culture influenced men's dynamic capabilities, but did not affect women's dynamic capabilities. Thus, this study represents that enterprises should build rational culture to business performance by utilizing the competence of female workers and have more concern on making environment for employees to exercise their dynamic capabilities.

Optimal sensor placements for system identification of concrete arch dams

Altunisik, Ahmet Can,Sevim, Baris,Sunca, Fezayil,Okur, Fatih Yesevi Techno-Press 2021 Advances in concrete construction Vol.11 No.5

This paper investigates the optimal sensor placements and capabilities of this procedure for dynamic characteristics identification of arch dams. For this purpose, a prototype arch dam is constructed in laboratory conditions. Berke arch dam located on the Ceyhan River in city of Osmaniye is one of the highest arch dam constructed in Turkey is selected for field verification. The ambient vibration tests are conducted using initial candidate sensor locations at the beginning of the study. Enhanced Frequency Domain Decomposition and Stochastic Subspace Identification methods are used to extract experimental dynamic characteristics. Then, measurements are repeated according to optimal sensor locations of the dams. These locations are specified using the Effective Independence Method. To determine the optimal sensor locations, the target mode shape matrices which are obtained from ambient vibration tests of the selected dam with a large number of accelerometers are used. The dynamic characteristics obtained from each ambient vibrations tests are compared with each other. It is concluded that the dynamic characteristics obtained from initial measurements and those obtained from a limited number of sensors are compatible with each other. This situation indicates that optimal sensor placements determined by the Effective Independence Method are useful for dynamic characteristics identification of arch dams.

Rolling element bearings absolute life prediction using modal analysis

Mostafa Yakout,A. Elkhatib,M. G. A. Nassef 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.1

In this paper, the authors introduce an experimental procedure for predicting the fatigue life of each individual rolling element bearing separately using vibration modal analysis. The experimental procedure was developed based on a statistical analysis. A statistical analysis was performed to find an empirical model that correlates the dynamic load capacity of rolling bearings to their dynamic characteristics (Natural frequencies and damping). These dynamic characteristics are obtained from the frequency response function of each individual bearing that results from vibration modal analysis. A modified formula to the already known Lundberg-Palmgren life formula is proposed for rolling element bearings. Given the modified formula, one can predict the fatigue life of each individual rolling element bearing based on its dynamic characteristics. The paper compares the results from the modified formula with those from Lundberg-Palmgren formula. The modified formula provides an accurate prediction for the fatigue life of each individual bearing based on its dynamic characteristics. The experimental validation of the modified formula is considered for future work. Therefore, it can be used in various applications of rolling element bearings in machinery systems.

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.

Time Dependent Changing of Dynamic Characteristics of Laboratory Arch Dam Model

Ahmet Can Altuni ik,Bar Sev m,Alemdar Bayraktar,Süleyman Adanur,Murat Günaydin 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.4

This paper investigates the time dependent changing of dynamic characteristics of laboratory arch dam models using ambient vibration test. For this aim, a prototype arch dam-reservoir-foundation model is constructed in laboratory conditions. The first experimental measurement tests are performed after the poured concrete aged for 10 months for some damage scenarios such as undamaged, minor-damaged and severely damaged of dam body in November 2009. To extract the experimental dynamic characteristics such as natural frequencies, mode shapes and damping ratios, a small impact effect is used as a source of ambient vibrations. Experimental measurements tests are repeated using same excitations considering severely damaged conditions with and without reservoir water in February 2014, and the dynamic characteristics are obtained, experimentally. Enhanced Frequency Domain Decomposition Method in the frequency domain is used to extract the experimental dynamic characteristics. At the end of the study, experimentally identified dynamic characteristics are compared with each other and time effects are investigated in detail. Maximum differences between the natural frequencies obtained as 15.36% and 14.38% in the third mode for empty and full reservoir conditions, respectively. It is thought that the increase of the natural frequencies is resulted from gaining of rigidity of the concrete, ageing, temperature and different environmental effects.

그라우트 주입율 변화에 따른 사질토의 동적계수 특성

안광국(Ahn Kwangkuk),박준영(Park Junyoung),오종근(Oh Jonggeun),이준대(Lee Jundae),한기환(Han Kihwan) 한국지반환경공학회 2011 한국지반환경공학회논문집 Vol.12 No.5

전단탄성계수와 감쇠비와 같은 동적지반계수는 반복하중과 동적하중을 받는 지반구조물 설계에서 중요한 요소이다. 선형한계변형률 내에서 미소변형률에 관한 전단탄성계수와 감쇠비는 변형률과 관계없이 일정하다. 전단탄성계수는 최대전단탄성계수로 감쇠비는 최소 감쇠비로 고려하였다. 동적변형특성 범주내의 최대선형탄성계수에 관련된 많은 시험들이 수행됨과 동시에 간극비, 과압밀비, 구속압, 지질이력, PI 그리고 하중주기수에 관련된 많은 인자들이 동적지반특성에 영향을 미친다. 그러나 그라우팅에 의해 향상된 지반동적특성에 관한 연구는 지하연속벽시공, 심층혼합처리공법, 강관다단그라우팅과 같이 미비한 실정이다. 본 논문에서는 그라우팅에 의해 향상된 동적지반특성을 연구하기 위하여 함수비(20%, 25%, 30%), 그라우트 주입율(5%, 10%, 15%),양생기간(7일, 28일)을 변화시키면서 공진주시험을 실시하였다. 그 결과, 밀크 그라우트의 주입율과 재령, 함수비에 따라 동적계수인 전단탄성계수와 감쇠비가 영향을 받는 것으로 나타났다. Ground dynamic parameter such as shear elastic modulus and damping ratio is a very important variable in design of ground-structure with repeated load and dynamic load. Shear elastic modulus and damping ratio on small strain below linear limit strain is constant regardless of strain. Shear elastic modulus as the maximum shear elastic modulus and damping ratio as the minimum damping ratio were considered. As a lot of experiment related to the maximum shear elastic modulus, which is in dynamic deformation characteristics, have been conducted, many factors including voiding ratio, over consolidation ratio(OCR), confining pressure, geology time, PI, and the number of load cycle affect to dynamic soil characteristic. However, the research of ground dynamic characteristic improved with grout is absent such as underground continuous wall construction, deep mixing method, umbrella arch method. In order to investigate the dynamic soil characteristics improved with grout, in this study, resonant column tests were performed with changing water content(20%, 25%, 30%) and injection ratio of grout(5%, 10%, 15%), cure time(7th day, 28th day) As a result, shear elastic modulus and damping ratio, which are ground dynamic parameter, are affected by the injection ratio of milk grout, cure time and water content.