• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.2
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• pp.119-131
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• 2005

The two dimensional behaviors of the existing upper tunnel and the ground at crossed area due to the excavation of a lower tunnel were studied experimentally, The model tests were conducted by changing the relative location of the existing upper tunnel and the lower tunnel. The results of the study show that a vertical earth pressure outside the loosened area was increased due to longitudinal arching effect same as a single tunnel. In case vertical distance between the upper and lower tunnel is 0.7 H and 1.0 H respectively (H is a height of the lower tunnel), vertical earth pressure increased in the loosened area behind the tunnel face. But when a vertical distance is 1, 3 H, ground behaviors appeared similarly to a single tunnel.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.1
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• pp.39-46
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• 2017

In this paper, a model updating procedure based on the response surface method combined with the multi-objective optimization was proposed and applied for updating of the FE models representing a low-rise reinforced concrete building before and after the seismic retrofit. The dynamic properties to be matched were obtained from vibration tests using a small shaker system. By varying the structural parameters according to the central composite design, analysis results from the initial FE model using a commercial software were collected and used to produce two regression functions each of which representing the errors in the natural frequencies and mode shapes. The two functions were used as the objective functions for multi-objective optimization. Final solution was determined by examining the Pareto solutions with one iteration. The parameters representing the stiffnesses of existing concrete, masonry, connection stiffness in expansion joint, new concrete, retrofitted members with steel section jacketing were selected and identified.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.1
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• pp.94-99
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• 2007

Many cases of acute cardiac shock and cardiac arrest in emergency room and ICU have been increasing. In this case, ECMO with centrifugal pump has been used generally. However, due to the heavy weight and big size, the system is not adequate for emergency cases. And other defects of this system are that membrane oxygenator's pressure is high and blood are exposed to the air. There was some tries of ECMO using pulsatile pump, but it was found that the weak point of these system is high peak pressure and hemolysis. The mechanism of twin pulsatile pump is that Membrane oxygenator Outlet Pump(MOP) make negative pressure when Membrane oxygenator Inlet Pump(MIP) provides high positive pressure, and the negative pressure will decrease positive pressure of Membrane Oxygenator. Our group analyzed this advantage through In-Vitro and 12 Cases In-Vivo test.

• Journal of the Korean Geotechnical Society
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• v.29 no.1
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• pp.71-80
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• 2013

Before and after the test constructions, and after an 11-month hiatus from the pilot pile installations, the in-situ tests (CPT, SPT) were carried out at the ground adjacent to the noise- and vibration-free screw concrete piles installed by 2 kinds of construction methods (i.e., the toe-jetting shoe type, the pre-digging type). In the toe-jetting shoe type construction methods, after construction, the soil strength within 3.5D (where, D = pile diameter) from the pile center decreased greatly by about 46% of the original ground and, after an 11-month hiatus, a strength recovery adjacent to the piles appeared about 71% of the original ground. In the pre-digging type construction methods, a strength recovery adjacent to the piles appeared 100% of the strength of the original ground.

• The Korean Journal of Rheology
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• v.6 no.1
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• pp.30-40
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• 1994

고분자 물질의 신장점도를 측정하기 위하여 설계된 수렴관을 지나는 시험 유체 M1 에대하여 유한요소방법으로 수치모사를 수행하였다. 구성방정식은 세 개의 이완시간을 가진 적분형 K-BKZ모형을 사용하였다. 신장변형이 지배적이고 변형속도가 매우 큰 흐름에 대하 여 실험적 방법으로 측정이 가능한 범위까지 수치모사를 수행하였다. 두 개의 압력 측정꼬 지 사이의 벽면 압력차에 대하여 압력 신호로 측정한 실험값을 수치모사결과와 비교하였다. 걷보기 전단속도가 매우 큰 1300s-1에 이르는 높은 유속의 전 실험범위에 대하여 안정된 수 치해를 얻을수 있었다. 3$0^{\circ}C$에서는 모든 실험범위의 유속에서 압력차에 대한 수치모사 결과 가 실험값과 잘일치했다. 21$^{\circ}C$에서는 0.1$\times$10-3m3/s보다 낮은 유속범위에서 실험값과 일치하 는 결과를 얻었으나 그보다 높은 유속에서 실험값과 일치하는 결과를 얻었으나 그보다 높은 유속에서 실험값과 다른 경향의 결과를 얻었다. 이것은 낮은 온도 높은 유속 조건에서 M1 유체의 성질이 불안정하고 또한 그러한 조건의 실험에서 발생한 압력 측정꼭지 부근의 기포 들이 정확한 압력측정에 영향을 끼쳤기 때문이다. 수치모사 결과로부터 얻은 압력과 응력분 포로부터 수렴관 유변측정기의 유동특성을 밝힐수 있었다. 이는 실험적 방법을 통해서는 얻 기 어려운 결과들로서 중요한의미를 가진다. 특별한 모양을 갖도록 설계된 수렴관을 통과하 는 M1 유체가 중심부근에서 일정한 신장변형속도로 변형됨을 확인할 수 있었으며 수직응력 은 지수적으로 증가하다가 축소부분을 지난 후 매우 장점도를 얻기 위하여 신장변형속도가 일정한 구역이 두 배로 확장된 수렴관이 수치적으로 다루어졌고 이를 통하여 기존의 수렴관 에서 구한 값보다 큰 신장점도를 얻을 수 있었다.

• Tunnel and Underground Space
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• v.27 no.6
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• pp.406-421
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• 2017

This study describes a precise numerical analysis process by adopting the real image of mine openings obtained by LIDAR, which can produce a point cloud data by measuring the target surface numerically. Research area is a section of underground limestone mine which is used hybrid room-and-pillar method for improving the production rate. From the application of LIDAR to this section several results were deduced, that is, the central axis of upper and lower vertical safety pillars is distorted to the direction of NW and the section area of lower vertical safety pillar is $34m^2$ smaller than the designed area of $100m^2$. The results of precise measurement in geometrical shape of mine openings and precise simulation in numerical analysis confirms that LIDAR techniques can be suggested as a valuable tool for stability analysis in underground mine by configuring the mine opening shape.

• Tunnel and Underground Space
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• v.18 no.5
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• pp.386-392
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• 2008

Recently, an earthquake-resistant has become essential to the large-scale structures at Gyeonggi and Gyeongsangnam province in Korea, but it is generally compared the measured data with foreign references because of the lack of the research data. It will be presented the characteristics of suitable dynamic elastic modulus in Korean geology, which characteristics are characterized the seismic wave velocities($V_p,\;V_s$) and correlation with dynamic elastic modulus($E_d,\;G_d\;K_d$) by each rock type of Korean granite, because it is very different between the values of foreign references and Korean geological characteristics.

• Journal of Sericultural and Entomological Science
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• v.8
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• pp.1-9
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• 1968

This experiment was carried on to investigate the root system of the half bench terracing mulberry field of 170cm wide at slope 1and. The results obtained are as follows; 1. Total root weight per nest in case of p1anting two sapling is from 2.4 to 2.8kg, of which most are over l0mm in diameter, 1-5mm intermediate, and below 1mm and 5-10mm fewest. Total root length. per nest is 177-255 meter except less than 1mm in diameter, of which 1-5mm is longest and over l0mm shortest. 2. From the view of vertical distribution of root, the weight and length of root (90%) are mostly concentrated 20cm below and then 20-40cm from the surface of land. 3. Most roots have grown right and left within 30cm from the mulberry stock. 4. Most roots have grown at 35-70cm block and 70-105cm block from front side of terrace, if further than this, roots have become fewer. Root distribution at front side is more considerable than that at rear side of terrace. 5. There was no significant difference among the mulberry varieties.

• Analytical Science and Technology
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• v.14 no.3
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• pp.266-273
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• 2001

One pulp manufacture facility was selected as surveying facilities to examine the discharged rate and generation mechanism of dioxin in bleaching stag wastewater. The analytical method was established in the wastewater and the sample was collected and analyzed. The outlet concentration of bleaching stage was increased 5 times for 2,3,7,8-TCDF and 7 times for OCDD, and the discharged ratio between PCDFs and PCDDs was surveyed about 2:3. The 2,3,7,8-TCDF and 2,3,7,8-TCDD were mainly detected in acid wastewater of bleaching stage that is known as the typical discharged patterns of chlorine bleaching stage.

• Journal of the Korean Society for Library and Information Science
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• v.45 no.4
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• pp.139-155
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• 2011

The failure of distinguishing homographs in describing relations of individual authors and relations of authorship(i.e. distinction of persons with the same name or persons of the same literary author's name) will cause difficulties of retrieving exact information. It is because relations of automorphism cannot be formed between the two sets mentioned above. Therefore, it is ultimately necessary to set up the criteria or tools to distinguish homographs in order to retrieve more exact information. In the past, some efforts were made to develop authority data in order to solve the homograph problems by individual libraries, documents and portal sites in Korea. It is well understood that developing authority data by an individual institution was very difficult with no criteria or no rules to clarify the homograph problems at the national level. This study is to develop ways of recognizing individual names including subject words and proper nouns. The results of the study will present methods of distinguishing and describing homographs between individual author sets, and authorship sets particularly focused on the areas of arts and popular culture.