• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.796-799
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• 2005

In 2005, a regulation on the heavy-weight impact sound was released, which restricted concrete slab thickness of standard floor to 210mm. To reduce heavy-weight impact sound, damping materials and structural reinforcement system have been proposed. In this study, the effect of compressive strength on the heavy-weight impact vibration and sound were investigated. FEM analysis was conducted for the 34PY apartment with different concrete strength (210, 350, 420kg/cm$^2$). In addition, apartment floors with different concrete strength were constructed and the floor impact vibration and sound were measured. Results of FEM analysis and measurement show that the resonance frequency of concrete slab was increased by the increment of concrete strength. However, floor impact sound pressure level did not decrease because the nor impact vibration and sound pressure level in 63Hz band increased.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.619-619
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• 2003

This study was intended to evaluate the influence of different base materials on the marginal integrity of posterior direct composite resin restorations. Large conventional butt-joint MOD cavity preparations, with margins in enamel and dentin, were prepared in vitro in 24 extracted human mandibular molars and randomly divided into four equal groups. One of three base materials(RMGI, compomer, flowable resin) was placed on the pulpal floors, of the teeth of the groups. One group of teeth, which served as the control group, was not given any base mterial.(중략)

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.4
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• pp.99-106
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• 2002

In the composite deck system, beams and deck plates deflect during construction. This lens-shaped deflection may cause problems in the serviceability of a building. Therefore, it should be compensated to be level. Several methods for leveling of floor slab are available, such as (1) increasing stiffness of structural members, (2) propping floor system, (3) cambering beams, (4) pouring additional concrete. In this study, additional weight and volume of concrete for level compensation are examined for various size of floors.

• Earthquakes and Structures
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• v.7 no.3
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• pp.385-400
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• 2014

Pounding damage to bridges and buildings is observed in most major earthquakes. The damage mainly occurs in reinforced concrete slabs, e.g. building floors and bridge decks. This study presents the results from pounding of reinforced concrete slabs. A parametric investigation was conducted involving the mass of the pendulums, the relative velocities of impact and the geometry of the contact surface. The effect of these parameters on the coefficient of restitution and peak impact acceleration is shown. In contrast to predictions from numerical force models, it was observed that peak acceleration is independent of mass. The coefficient of restitution is affected by the impact velocity, total participating mass and the mass ratio of striker and struck block.

• Structural Engineering and Mechanics
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• v.46 no.4
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• pp.505-518
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• 2013

In this study, the seismic performance of a residential building which was damaged in the 1992 Erzincan (Turkey) Earthquake (Ms = 6.8) is performed. Damages on columns due to short columns are estimated analytically implementing the shear hinges and results are compared with the observed damages on the building after the earthquake. In seismic performance evaluation, a deformation based approach is adopted, whereby the structural behavior under external and seismic loads is evaluated. Furthermore, the effects of short columns formed by band windows in basement floors are investigated analytically. The sizes of band windows are parametrically changed in order to understand the effects of short columns on overall building behavior.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.29 no.4
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• pp.91-99
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• 2006

A POP system, which collects manufacturing data from the shop floors and supply them to higher level systems, should be maintained and upgraded according to the change of production environment such as new product introduction. This situation leads to the need of a cost-effective system development methodology. In this paper, a methodology based on the classification and the similarity comparison of manufacturing processes is proposed. In this, a new product is classified according to the similarity of its manufacturing processes, which enables recycling of existing system modules. The proposed methodology has been tested in the case of an electronics parts manufacturing company, where a POP system is implemented. The result shows that the proposed methodology can save time and efforts for system implementation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.23
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• pp.71-100
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• 1991

Investment in FA facilities has been accerelated since 1986, turning point by labor strife in Korea firms. Most commonly adopted automation tech, in their manufacturing process consists of NC. Robotics, PLC, CAD/CAM now on and further confused system oriented FMS, CIM, etcs. undergoing. But for all their remarkable notices in manufacturing systems, The competitive position on product cost, quality, shorten delivery and profit has never been recovered in global swing market. To make some empirical suggestions with a view to competitive strategy of Korea firms by FA, to the conclusion largely FA tech. adoption can be justified only when its application on new product productions and improved the structure of products comparatively. Because of when it was applied in old production process. The effectiveness is very doubtful to the lacks of consistent and integrate manufacturing policy with the strategy of the fim and their poor standardization level in shop floors.

• Journal of the Korea Safety Management & Science
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• v.5 no.4
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• pp.209-217
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• 2003

The traditional Kanban needs a lot of preconditions for fitting conditions of dynamic production processing environment. The traditional Kanban isn't suitable conditions of dynamic production processing environment. Therefore conditions of dynamic production processing environment is needed more stable system. This study is describe CONWIP system such as suitable in dynamic production processing environment. Most Pull system is a Kanban system than use Kanban cards or signal for production management and inventory control. The object of Kanban system is reducing inventory between shop-floor that can reduce inventiry cost. If the system reduce the number of Kanban cards would be reduce the working process WIP, can be reduced and can be found all potential problem of production between shop-floors. This study apply to CONWIP system model for Korean industrial companies.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.381-386
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• 2006

This study is to research application cases of domestic ventilation system for developing ventilation system which is energy-saving and improve Indoor Air Quality and to research application possibility of foreign hybrid ventilation system. This is a basic research data of developing ventilation system for energy saying and improving indoor quality which that research the function and a feature of the ventilation system which is applied in five domestic skyscrapers over 30 floors, and research application instances and features of foreign hybrid ventilation system.

• Earthquakes and Structures
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• v.17 no.3
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• pp.283-295
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• 2019

During the seismic performance assessment of existing buildings, staircases are generally not taken into account as structural members but as dead load. Staircases, as secondary structural members, not only serve for connecting successive floors but also provide considerable amount of strength and stiffness to the building which can modify its seismic behaviour considerably. In this parametric study, the influence of staircases on the seismic response of substandard RC frame buildings which differ in number of storey and span, presence of staircase and its position has been examined. Modal Analyses and bi-directional Non-Linear Time History Analyses (NLTHA) were conducted to compare several engineering demand parameters (EDPs) such as inter-storey drift ratio (ISDR), floor accelerations, modal properties, member shear forces and plastic hinge distribution. Additionally, short column effect, variation in shear forces of columns that are attached to the staircase slab, failure and deformation in staircase models have also been investigated. As the staircase was considered in the analytical model, a different damage pattern can be developed especially in the structural components close to staircase.