• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.65-75
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• 2004

In this paper, a mechanism of the soil structure reinforced by geosynthetics is discussed. The reinforcing mechanism is interpreted as an effect arising from the reinforcement works preventing the dilative deformation (negative dilatancy) of soil under shearing. A full-scale in-situ model test was carried out in Kanazawa of Japan (1994), and in the laboratory test the strength and the characteristics of deformation conducting a constant volume shear test are examined. The parameters needed in the FEM are also applied by using the experimental data. The elasto-plastic finite element simulation is carried out, and the results are quantitatively compared with that of experiment. As a results, it is known that the theoretical predictions could explain effectively the experimental results which are obtained by a full-scale in-situ model test.

• Journal of the Korean Geotechnical Society
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• v.29 no.11
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• pp.85-97
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• 2013

Electric pole foundations for overhead catenary system of railroad should be designed so that they may resist significant overturning moment but relatively small vertical forces. Also they should have proper shapes to be installed at restricted narrow areas adjacent to railroad track. In this paper the moment responses of rectangular pole foundations according to their shapes were investigated numerically. A three-dimensional finite element method was developed and verified so that the numerical behaviors of the foundation resisting the overturning moments were compared reasonably well with those from an existing real-scale load test. The influences of aspect ratio, varying section with depth and loading directions for rectangular section were investigated using the developed numerical method. From the numerical results, the optimized shapes of pole foundation for more effective and economic installation adjacent to railroad track are proposed.

• KIEAE Journal
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• v.6 no.2
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• pp.67-74
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• 2006

As sustainable design technologies, advanced daylighting systems with lightshelves have been developed and are currently under monitoring the daylighting performance. This study aims to evaluate the comparative daylighting performance of sloped lightshelf and conventional glazing window with mock-up model, reconstructed as a prototype of Korean office building, sized $12.0m{\times}7.3m{\times}3.7m$ ($w{\times}d{\times}h$) and $1.8m{\times}4.8m$($w{\times}h$) for the south facing side-window was installed on the rooftop of engineering building, Kyung Hee University in Korea. It has an identical configuration of reference room and the test room. For the test room, the sloped type lightshelf system was designed as 10mm transparency sheet glass, tilt angle degree $29^{\circ}$, and total sized 1.28m (interior length 0.88m, exterior length 0.49m). It consisted of daylighting collector, entrance glazing and reflector. To assess daylighting performance, the totally 37 measuring points for illuminance and 2 view points of luminance were monitored in every 30 minutes from 12:00 to 15:00. For the detailed analysis, photometric sensors of each room were installed at work-plane (8 points), wall (7 points), ceiling (3points), and exterior horizontal illuminance (1 point). Luminance of window, rare of the room was measured under clear sky. It is to be monitored by Agilent data logger, photometric sensor Li-cor and the Radiant Imaging ProMetric 1400. Comparisons with a light factor, increase-decrease ratio, uniformity, and luminance are discussed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.7A
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• pp.967-977
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• 2000

In this paper, we apply a mixed $H_2/H_{\infty}$ control to a generalized plant of inverted pendulum system represented by an LFR(Linear Fractional Representation). First, in order to obtain the generalized plant, the linear model of the inverted pendulum represented by an LFR(Linear fractional Representation) is derived. In LFR, we consider system uncertainties as three nonlinear components and a pendulum mass uncertainty. Augmenting the LFR model by adding weighting functions, we get a generalized plant. And then, we design a mixed $H_2/H_{\infty}$ controller for the generalized plant. In order to design the mixed $H_2/H_{\infty}$ controller, we use the LMI technique. To evaluate control performances and robust stability of the mixed $H_2/H_{\infty}$ controller designed, we compare it with the $H_{\infty}$ controller through the simulation and experiment. In the result, with the fewer feedback information, the mixed $H_2/H_{\infty}$ controller shows the better control performances and robust stability than the $H_{\infty}$ controller in the sense of pendulum angle.

• KDI Journal of Economic Policy
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• v.26 no.1
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• pp.3-33
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• 2004

This paper investigates the effects of inflation on real estate prices, particularly the discrepancy between the sales and chonsei prices of housing, in an economy in which real interest rates are secularly declining due to the fall in capital productivity. When real interest rates fall, real estate prices rise relative to chonsei prices, and thus the well-known adverse effect of inflation, or the discrepancy between the value of financial assets (or chonsei principal) and the value of real assets (or real estate), is aggravated although the monetary authority maintains the same rate of inflation. This theoretical prediction can help explain the trend of the ratio of apartment sales prices to chonsei prices. That is, the stabilization of inflation relative to real interest rates appears to have contributed to the secular stabilization of this ratio in the 1990s, while the fall in real interest rates appears to have led to the rise of this ratio since 2001.

• KDI Journal of Economic Policy
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• v.20 no.1_2
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• pp.153-230
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• 1998

우리나라의 소득분배문제에 대해서 종래에는 적어도 1980년대 이후 개선되고 있으며, 국제비교에서도 다른 나라에 비해 결코 나쁘지 않다는 평가가 주류를 이루고 있었으나, 최근에는 그에 대한 반론이 만만치 않게 전개되고 있다. 본고에서는 "도시가계연보"의 원자료를 이용한 새로운 추계를 시도하여 1980년대의 소득분배가 지금까지의 통설처럼 그렇게 많이 개선된 것은 아니라는 결과를 제시하였다. 마찬가지로 일부의 반론처럼 1980년대의 소득분배가 실제로 악화되었다는 주장도 과장일 가능성이 크다는 점도 지적하였다. 단, 근로소득의 분배가 개선되고 있음은 분명하나 토지나 주식 등에 의한 불로소득까지 포함하면 결과는 크게 달라질 수 있다. 이 문제의 검증은 아직 끝난 것이 아니며, 올바른 결론에 도달하기 위해서는 앞으로 보다 많은 자료들이 발굴, 분석되어야 할 것이다. 한국의 자산분배에 대해서는 지금까지 자료가 별로 없어서 논의 자체가 어려운 상태였다. 최근 대우경제연구소의 패널 자료를 분석해본 결과, 한국의 부의 분배는 지금까지 알려진 것보다 훨씬 더 불평등하며, 특히 토지 등 실물자산의 불평등이 심각한 것으로 나타났다. 한편 한국의 빈곤은 많이 줄어든 것이 사실이며, 다른 후진국과 비교해서 빈곤 축소에 큰 성과를 거둔 것으로 평가된다. 본고에서 좀더 현실적인 최저생계비를 가정하여 분석해본 결과 한국의 빈곤은 물론 많이 줄어들었지만 아직 상당히 남아 있으며, 빈곤의 크기 자체(빈곤 갭)는 그다지 크지 않은 것으로 나타났다. 본고에서는 이러한 연구결과에 기초해서 우리나라의 분배문제에 대한 평가를 내리고 효율성과 형평성의 조화라는 관점에서 정책의 기본방향을 설정하였으며, 조세정책가 재벌정책에 초점을 맞추어서 정책방향을 논의하였다. 분배정의 관점에서, 우리나라의 세제는 직접세 비중을 높이고, 종합토지세, 상속 증여세 등 재산관련 세제의 기능을 강화하며, 근로자와 비근로자간 세부담의 형평성을 제고하는 방향으로 개편되어야 한다. 그리고 재별의 소유분산 자체보다는 재벌이 자행할 수 있는 경제적 부조리를 막기 위한 장치를 강화하는 것이 중요하다. 상속 증여세제 등의 강화나 기업경영의 투명성을 제고하기 위한 감시장치가 강화되어야 할 것이다. 특히 자유주의자가 강조하는 '정당한 권리의 원칙'으로서 '부정의의 시정'의 원칙이 보다 적극적으로 반영될 수 있어야 하며, 이러한 주장 자체가 시장 메커니즘을 옹호하는 진정한 자유주의 원칙에 입각하고 있다는 점이 강조되어야 할 것이다.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.359-366
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• 2013

In this paper, we studied how the data obesity can affect in which the response speed of database gradually slows down. Our research is performed by analyzing how the game data infrastructure is well-formed. Although there are a variety of ways to evaluate to measure the level of infrastructure, we performed with real information system. We analyzed data obesity by comparing the entity-relationship models between the products of real game information system and newly modeled databases. We could find data obesity is over 60% among overall average of game information system. It shows that 45% higher than standard obesity which is 15%. In this paper, data redundancy rate after performing the procedure of the data modeling was 41% resulting in an improvement of 23% compared to 64% of an existing model.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.1
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• pp.37-43
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• 2002

Recently, the construction of tunnels longer than one kilometer has increased rapidly. Considering characteristic of limiting structure of longer tunnel, if fires inside tunnel broke out because of vehicle incidents, the catastroph would have high possibility to take place due to toxic smoke and heat of fire. In case of highway tunnel, safety facilities which can cope with tunnel fire are installed in the tunnel but according to rapid increase of heavy good traffic, dangerous goods and enlargement of tunnel magnitude, the research has to carry out about heat fluxes and smoke behaviour during tunnel fire. Therefore, through full-sized fire experiment the paper analyzed temperature distribution, wind velocity, smoke behaviour during tunnel fire.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.5
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• pp.533-540
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• 2013

Prime movers in engine rooms inherently are much affected by the adjustment of their governors for the steady state and transient properties, consequently requiring that marine engineers shall be well familiar with the way to manage governor dials for normal operation. The hydro-mechanical governors basically have different control characteristics and adjustment parameters of stability from digital governors. The former include compensation mechanism using dash pot while the control algorithm of the latter is usually based on the PID action. This study is for configuring a simulation module to let trainees practice how to adjust dials for stability on hydraulic governors in the view that the practice by real governors and engines is time consuming and high cost for operation. The governor module includes the adjusting points such as speed set, speed droop, needle valve and compensation pointer with engine module of $2^{nd}$ order coupled. The results of simulation showed satisfactory responses as a training tool for the adjustment of control parameters.

• Journal of the Korean Geophysical Society
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• v.6 no.4
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• pp.277-294
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• 2003

Structures show the phenomena of deformation and lowering of function with time-lapse by artificial environments and changes of geotechnical conditions or accumulation of initial deformation elements. This study aims the structural assessment of cultural property, Chum-Sung-Dae, located in Kyeongjucity, Korea. It was built about 1,300 years ago, and has undergone deformation and ground-subsidence with time-lapse. Non-destructive evaluation techniques were applied to the Chum-Sung-Dae, to protect it from survey. Because of this reason, 3D precise laser scanning surveying system was applied to measure the exact size of Chum-Sung-Dae, displacement and declining angles. Geophysical exploration also was applied to study the subsurface distribution of geotechnical parameters or physical properties. Natural frequencies were measured from real and model of Chum-Sung-Dae to study the dynamic characteristics of vibration and/or earthquake load and stiffness of structures.