• Journal of the Korean Society of Safety
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• v.7 no.1
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• pp.31-38
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• 1992

This paper presents a study on application of expert system technique for the diagnosis of fire-causes in plants. A need is recognized for new methods to diagnose exactly the causes of fires without the help of the human experts. To cope with the difficulty, the expert system techiuque is applied to this area. The expert system suggested in this paper is developed to infer the causes of fires(or, ignition source ) by using the information drawn from the circumstances in fire. For the convenience of inference, ignition sources we classified into eight types ; elecoic spark, adiabatic compression, welding spark, material of high temperature, impact and friction, spontaneous ignition, naked fire, and static electricity. The knowledge base is composed of the rule base and dynamic database, which contain the rules and facts obtained by the expenence in this area, respectively. Both depth-first search and backward chaining schemes are used in reasoning process. This expert system is written in an artificial intelligence language "PROLOG", and its availability is demonstrated through the case study.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.31-36
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• 2010

This paper introduces a practical determination method for soil parameters adopted in the new performance based design code for port and harbour facilities in Japan. In the new port-design code, the depth profile of the derived values is modeled as the profile of the estimated values so as to be either the mean value or the regression line, then the correction factors are multiplied to the estimated value according to the coefficient of variation (if COV > 0.1) and the number of the data entries (if n < 10). The new port-design code is applied to the unconfined compression test results for the Hiroshima Port clay in order to evaluate the undrained shear strengths. From the discussion, it is emphasized that not only the statistic treatment but also the engineering judgment are required in the procedure of the soil parameter determination for the reliability design.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.61-64
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• 2004

This study presents results from an experimental work for two normal prestressed concrete beams and three dual prestressed concrete beams. The dual prestressed concrete beams made with normal concrete in compression zone and high performance steel fiber reinforced concrete in partial depth of tension zone. Through cyclic loading test under low frequency, structural behavior and resistance to dynamic loading for dual prestressed concrete beams are investigated. Considerable increase of crack and yield load capacity of Dual prestressed concrete beam is shown compared with normal prestressed concrete beam. In addition, re-loading and un-loading rigidity of dual prestressed concrete beam under cyclic loading are increased comparing with normal prestressed concrete beam.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.4
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• pp.343-351
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• 2010

Bending and axial compressive stresses are distributed across the whole upper flange of a box girder bridge which has the span-to-depth ratio (B/L) of below 0.5, according to Korea Bridge Design Specifications (Minister of Land, Transport and Maritime Affairs, 2005). Shear lag phenomenon, however, can take place in the construction phase of cable-stayed bridge, in which stresses combining bending moment due to dead weight and cable vertical compression are induced. This study aims to analyze the effective width of flange over which composite stresses are given, which should be calculated during the construction phase of stiffening girder of single plane cable-stayed box girder bridge. The study results indicate that the full width of stiffening girder can be regarded as the effective flange width when the span-to-depth ratio for the deck is below 0.38. In other words, the area, where shear lag is taken into consideration, is larger than the width of box girder in single plane cable-stayed box girder bridges. Therefore, the current practice of considering the full width as the effective flange width regardless of changes of the span-to-depth ratio during the construction stage can produce an unsafe bridge. If the effective flange width is determined according to the single span structural system in the early stage of construction when the span-to depth ratio for the deck is high and composite stresses of every part expect each end of the bridge are calculated, it can result in a safe structural design. Since the span-to-depth ratio gradually decreases, however, it is appropriate to determine the effective width of flange on the basis of the full width and the cantilever structural system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.6
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• pp.118-126
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• 2011

The objective of this paper is to study the structural behavior of Composite Basement Wall (CBW) according to shear span-to-depth ratio through an experiment and predict the nonlinear behavior of CBW by using ADINA program widely has been being used for FE analysis. Especially, this study focuses on the part of CBW in which the Reinforced Concrete (RC) is under compression stress; At the region of CBW around each floor, RC part stresses by compressive force when lateral press by soil acts on the wall. The contact condition between RC wall and steel (H-Pile) including stud connector is main factor in the analysis since it governs overall structural behavior. In order to understand the structural behavior of CBW whose RC part is under compressive stress, an experimental work and finite element analysis were performed. Main parameter in the test is shear span-to-depth ratio. For simplicity in analysis, reinforcements were not modeled as a seperated element but idealized as smeared to concrete. All elements were modeled to have bi-linear relation of material properties. Three type of contact conditions such as All Generate Option (AGO), Same Element Group Option with Tie(SEGO-T) and Same Element Group Option with Not tie(SEGO-NT) were considered in the analysis. For each analysis, the stress flow and concentration were reviewed and analysis result was compared to test one. From the test result, CBW represented ductile behavior by contribution of steel member even if it had short shear span-to-depth ration which is close to "1". The global composite behavior of CBW whose concrete wall was under compressive stress could be predicted by using contact element in ADINA program. Especially, the modeling by using AGO and SEGO-T showed more close relation on comparing with test result.

• Journal of Korean Academy of Nursing
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• v.42 no.3
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• pp.361-368
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• 2012

Purpose: The purpose of this study was to analyze the cardiopulmonary resuscitation skills and teamwork of nurses in simulated cardiac arrests in the hospital. Methods: A descriptive study was conducted with 35 teams of 3 to 4 registered nurses each in a university hospital located in Seoul. A mannequin simulator was used to enact simulated cardiac arrest. Assessment included critical actions, time elapsed to initiation of critical actions, quality of cardiac compression, and teamwork which comprised leadership behavior and communication among team members. Results: Among the 35 teams, 54% recognized apnea, 43% determined pulselessness. Eighty percent of the teams compressed at an average elapsed time of $108{\pm}75$ seconds with 35%, 36%, and 67% mean rates of correct compression depth, rate, and placement, respectively. Thirty-seven percent of the teams defibrillated at $224{\pm}67$ seconds. Leadership behavior and communication among team members were absent in 63% and 69% of the teams, respectively. Conclusion: The skills of the nurses in this study cannot be considered adequate in terms of appropriate and timely actions required for resuscitation. Future resuscitation education should focus on improving the quality of cardiopulmonary resuscitation including team performance targeting the first responders of cardiac arrest.

• Journal of the Korean Geosynthetics Society
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• v.5 no.1
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• pp.15-23
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• 2006

Sand Compaction Pile and Stone Column method have been used in widely during several decades as a technique to reinforce soft soils and increasing ultimate bearing capacity, accelerate consolidation settlement of the foundation ground. Stone column method, making a compaction pile using crushed stone, is a soft ground improvement method. However, stone column method is difficult to apply to the ground which is not mobilized enough lateral confine pressure because no bulging failure resistance. Hence, in present study, development the geogrid reinforced stone column system for settlement reduction and wide range of application of stone columns. To develop this system, triaxial compression tests were conducted for evaluation which is about behavior characteristics of stone column on replacement rate and confine pressure. Then, 3-dimensional numerical analysis were evaluated for application of the GRSC (geogrid reinforced stone column) system as evaluate behavior characteristics and settlement reduction effect of stone column reinforced by geogrid on types and reinforcing depth change of geogrid.

• Tunnel and Underground Space
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• v.26 no.2
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• pp.68-86
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• 2016

Understanding the frictional properties of rock discontinuities is crucial to ensure the stability of underground structures. In particular, the frictional behavior at depth depends on the complex interaction among mechanical, hydraulic, thermal and chemical characteristics and their coupled effects. In this study, a series of shear tests were carried out in a triaxial compression chamber to investigate the shearing behavior of saw-cut granite surface and rough shear surface of synthetic rocks. The test results were analyzed using Coulomb's shear strength criterion. The frictional behavior of saw-cut granite surface showed little variation at different confining, water pressures and temperature conditions, however in case of synthetic rocks, the frictional behavior showed different trend depending on normal stress level. In addition, the variation of stiffness and dilation at different testing conditions were analyzed, and the stiffness and dilation showed little variation at different water pressures and temperature conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.480-489
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• 2015

This study aimed to compare the education effect of easily accessible cardiopulmonary resuscitation (CPR) applications on smart-phones. The differences of performance and accuracy of CPR between animation CPR group and modified Pocket CPR group in Reserve Officers' Training Corps students of K university were evaluated by 2010 AHA guidelines. Data were collected from May 19, 2012 to May 20, 2012. There was no statistically significant difference between both of group in the performance and accuracy of CPR. However, the modified Pocket CPR group showed significant increase in the accuracy of chest compression depth (26.4%, p<.05), while the animation CPR group showed significant increase in the accuracy of chest compression location after the education (25.2%, p<.01). In conclusion, the methods using advantage and complementing disadvantage of animation CPR application and Pocket CPR application could help that people could easily access and perform to CPR.

• Journal of Biomedical Engineering Research
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• v.31 no.1
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• pp.56-66
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• 2010

The various total replacement artificial discs have developed because spinal fusion has shown a lesser mobility of an operated segment and an accelerated degeneration at adjacent discs. But almost artificial discs have not yet been reached on the substitute surgery of fusion because many problems such as those clinical success rates were not more than them of fusion have not solved. In this paper, vertically inserted assemble-screw fixture in vertebrae was proposed to improve the fixed capability of artificial disc. And also, to evaluate the design suitability of newly designed screw-type, including fixtures of commercial discs such as wedge and plate type, the 1/4 finite element model with a vertebra and various implanted fixtures were generated, and next, 3 bending motions such as flexion, bending and twisting under the moment of 10Nm and compression under the force of 1000N were considered, respectively and finally, FE analyses were performed. Results of three fixture types were compared, such as Range of Motion and maximal stress, and so on. For ROM, the screw type was average 58% less than the wedge type and was average 42% less than the plate type under all loading conditions. For average stress ratio at closer nodes between vertebra and each fixture, the wedge type was the lowest as minimum 0.02 in twisting, screw types were the highest as maximum 0.28 in compression. As the results of using cement material, it was predicted that the instability problem of the wedge type was better solved. The screw type which could be increased by implanting depth according to the number of assembling mid screws, showed that the decreased tendency of ROMs and maximal cancellous bone stresses. In further study, controlling the number of assembling screws that was suitable for a patient's bone quality, development of surgical tools and keeping on design supplementations, which will be able to develop the competitive artificial disc.