• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.25 no.1
• /
• pp.75-82
• /
• 2016

In this study, a cross-damped low vibration controller was developed to reduce vibration in ultra-precision dual stage driven by master/slave principle. In master-slave structure, the master stage leads the driving motion and the slave stage follows it so as to maintain a constant gap between two stages. In this structure, a small perturbation of master stage makes big oscillations in slave servoing stage, so a low damped master stage composed of voice coil motor makes a long vibration in settling area after driving motion profile. In this research, an effective feedback damping algorithm for increase the damping characteristics of the dual stage was developed. The designed velocity damping algorithm improves the system stability and reduces the settling time of the whole system. Simulation and experimental results show that the developed algorithm reduces settling time and improves the regulating performance.

• KSTLE International Journal
• /
• v.3 no.1
• /
• pp.1-6
• /
• 2002

The purpose of this paper is to investigate the effects of design parameters on the friction loss in piston skirt. An analytical model to describe the friction characteristics of piston skirt has been presented, which is based on the secondary motion of piston and mixed lubrication theory, It could be shown that the skirt friction closely depends on the side force acted on the piston pin. The side force is inf1uenced by cylinder pressure at low engine speed, but by inertia force at high engine speed. The usage of extensive skirt area and low weight piston is effective to reduce the friction loss at high speed. The low viscosity oil considerably decreases viscous friction as engine speed increases, but it increases boundary friction at low engine speed. From the parametric study, it is found that the skirt axial profile is the most important design parameter related to the reduction of skirt friction.

• Transactions on Electrical and Electronic Materials
• /
• v.18 no.5
• /
• pp.257-260
• /
• 2017

In this paper, we present the design of a 4.5 V low dropout (LDO) voltage regulator implemented in the 130 nm CMOS process. The design uses a two-stage cascaded operational transconductance amplifier (OTA) as an error amplifier, with a body bias technique for reducing dropout voltages. PMOS is used as a pass transistor to ensure stable output voltages. The results show that the proposed LDO regulator has a dropout voltage of 32.06 mV when implemented in the130 nm CMOS process. The power dissipation is only 1.3593 mW and the proposed circuit operates under an input voltage of 5V with an active area of $703{\mu}m^2$, ensuring that the proposed circuit is suitable for low-power applications.

• Land and Housing Review
• /
• v.4 no.3
• /
• pp.211-223
• /
• 2013

Massive migration is underway in rapidly urbanizing Guangzhou, the south gate of P. R. China. Over half the migrants choose to rent in "villages-in-the-city" in the downtown area because of the low-cost and prime location. The overpopulation and resulting poor environment and high crime-rate turn villages-in-the-city into de facto ghettos. As a result, these ghettos are undergoing a manner of demolition-development, leaving migrants' housing needs unmet. A private-sector initiative-the Tulou Commune-intends to address this considerable market potential. Targeting low-income groups, the Tulou Commune creates a socio-spatially exclusionary enclave. This paper analyzes the Tulou Commune and the implications if more low-income migrants shifting from village-in-the-city (excluded ghetto) to Tulou Commune (exclusionary enclave). This study argues that the intervention of the private sector causes the demographic, social, and spatial similarities and differences of the two living arrangements. Socioeconomic and institutional factors also affect the initiative. This study also provides more empirical evidence in the field of low-cost housing and socio-spatial development in transitional Chinese cities. As the first project of its kind, the analysis of the case can suggest how to improve strategies for accommodating migrants in the future.

• Korean Institute of Interior Design Journal
• /
• no.21
• /
• pp.42-53
• /
• 1999

The purpose of this study is to clarify the relationship between the exhibits layout and the spatial organization in exhibition spaces. As an analytical method, the space syntax theory devised by Bill Hillier(1984) was applied for analysing the potential differentiation of exhibition spaces and remodeling method in Seoul City Museum selected for case study. The results are as following. Especially from the convex analysis, axial analysis and exhibits(interpretation); 1) the closed spatial system(1F) has high visibility and high intelligibility in hall area but lacks route continuity, 2) the circulated spatial system(2F) has low global visibility but offers high intelligibility and connectivity due to its coercive circulation, 3) and the organization of exhibition design consists in differentiating space that reintegrates them into another spatial order. Therefore, there process are expected to provide a methodological framework for analysing and interpreting spatial organizations of design, leading to the clear explanation of remodeling.

• Proceedings of the IEEK Conference
• /
• 2002.07c
• /
• pp.1736-1739
• /
• 2002

The advanced in semiconductor, hardware, and software technologies enables the integration of more com- plex systems and the increasing design complexity. As system design complexity becomes more complicated, System-level design based on the If block and processor model is more needed in most of the RTL level or low level. In this paper, we present a novel approach fur the system-level design, which satisfies the various required constraints and an optimization method of image encoder based on codesign of function, algorithm, and architecture. In addition, we show an MPEG-4 encoder as a design case study. The best tradeoffs between algorithm and architecture are necessary to deliver the design with satisfying performance and area constraints. The evaluations provide the effective optimization of motion estimation, which is in charge of an amount of performance in the MPEG-4 encoder module.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2002.06a
• /
• pp.57-76
• /
• 2002

As piling works in urban area increasing, SIP which is low noise & vibration piling method is taking place of driven pile which has good bearing charateristics and economics. Since SIP has been used for more than 15 years and it's application is increasing year by year, however, accurate analysis of bearing mechanism of SIP is not enough. So the design of SIP is much more conservative than driven pile. This paper is aimed to analyse the bearing charateristics of 103 SIPs constructed in Korea to give rational design criteria. Research result shows that bearing capacity of SIP is 40% lower than that of driven pile and conservative Meyerhof(equation omitted) method produced closer result to load test results than other design method. And this result show that to use optimised design criteria for the economic SIP design, quality control criteria must be settled down to produce high in-situ bearing capacity.

• Korean Journal of Agricultural Science
• /
• v.28 no.2
• /
• pp.108-115
• /
• 2001

In this study, to propose the reasonable evaluation method of degree of consolidation considering the depth of soft ground, the two soft ground areas were chosen and analyzed for the consolidation degree. One was a western coast area in which depth of soft ground was low, and the other was a southern coast area in which depth of soft ground was deep. At the area in which depth of soft ground was low, Barron's and Yoshikuni's methods showed that the evaluation of consolidation degree was large, and it is reasonable that $C_h=C_v$ be recommended to apply the Hansbo's and the Onoue's methods. At the area in which depth of soft ground was deep, it is reasonable that $C_h=C_v$ be recommended to apply the Barron's and the Yoshikuni's methods, and $C_h=(2{\sim}3)C_v$ to apply the Hansbo's and the Onoue's methods. According to the Hansbo's and Onoue's methods, degree of consolidation proved to be applicable with measured data when using the $k_s=(1/3)k_v$ at the area which depth of soft ground was low and using the $k_s=(1{\sim}1/2)k_v$ at the area which depth of soft ground was deep. According to the Hansbo's and Onoue's methods, degree of consolidation was proved to be applicable with measured data when using ds=(3~5)dm at the area which depth of soft ground was low and using ds=2dm at the area which depth of soft ground was deep.

• Journal of the Society of Naval Architects of Korea
• /
• v.51 no.4
• /
• pp.300-310
• /
• 2014

This paper presents a mooring design procedure of a floating offshore wind turbine. The environment data of south offshore area of Jeju collected from Korea Hydrographic and Oceanographic Administration(KHOA) are used for hydrodynamic analyses as environmental conditions. We considered a semi-submersible type floating wind turbine based on Offshore Code Comparison Collaborative Continuation(OC4) DeepCWind platform and National Renewable Energy Laboratory(NREL) 5 MW class wind turbine. Catenary mooring with studless chain is chosen as the mooring system. Important design decisions such as how large the nomial sizes are, how long the mooring lines are, how far the anchor points are located, are demonstrated in detail. Considering ultimate limit state and fatigue limit state based on 100-year return period and 50-year design life, respectively, longterm predictions of breaking strength and fatigue are proposed.

• Journal of The Korean Digital Architecture Interior Association
• /
• v.13 no.4
• /
• pp.69-76
• /
• 2013

As the energy consumed in building area has occupied a lot when looking into energy usage weights in area over the world, energy reduction building, eco-friendly architecture comes to the fore in the modern architecture. Discussions on the eco-friendly architecture have various concept definitions and targets to be achieved.The architectural works of Norman Foster are expressed as high-tech buildings using iron, glass, etc. in appearance, but they appear as those buildings with low energy load by analyzing environmental conditions from initial design stage that each building has, utilizing natural energy with design of outer shell and applying proper technical system. Thus, this study aims at providing basic data of outer shell planning through eco-friendly element technologies by considering pattern and outer shell design of buildings, principles of eco-friendly building plan as an eco-friendly building planning technique of Norman Foster as an example of plans to utilize building pattern, outer shell design and natural environments, in order to utilize passive measures as much as possible to increase energy saving methods and increase comfort by analyzing element technologies in the eco-friendly architecture in line with the modern flow.