• International conference on construction engineering and project management
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• 2022.06a
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• pp.1250-1251
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• 2022

Measuring management is an important part of preventing the collapse of retaining walls in advance by evaluating their stability with a variety of measuring instruments. The current work of measuring management requires considerable human and material resources since measurement companies need to install measuring instruments at various places on the retaining wall and visit the construction site to collect measurement data and evaluate the stability of the retaining wall. It was investigated that the applicability of the current work of measuring management is poor at small and medium-sized urban construction sites(excavation depth<10m) where measuring management is not essential. Therefore, the purpose of this study is to develop a laser sensor-based hardware to support the wall displacement measurements and their control software applicable to small and medium-sized urban construction sites. The 2D lidar sensor, which is more economical than a 3D laser scanner, is applied as element technology. Additionally, the hardware is mounted on the corner strut of the retaining wall, and it collects point cloud data of the retaining wall by rotating the 2D lidar sensor 360° through a servo motor. Point cloud data collected from the hardware can be transmitted through Wi-Fi to a displacement analysis device (notebook). The hardware control software is designed to control the 2D lidar sensor and servo motor in the displacement analysis device by remote access. The process of analyzing the displacement of a retaining wall using the developed hardware and software is as follows: the construction site manager uses the displacement analysis device to 1)collect the initial point cloud data, and after a certain period 2)comparative point cloud data is collected, and 3)the distance between the initial point and comparison point cloud data is calculated in order. As a result of performing an indoor experiment, the analyses show that a displacement of approximately 15 mm can be identified. In the future, the integrated system of the hardware designed here, and the displacement analysis software to be developed can be applied to small and medium-sized urban construction sites through several field experiments. Therefore, effective management of the displacement of the retaining wall is possible in comparison with the current measuring management work in terms of ease of installation, dismantlement, displacement measurement, and economic feasibility.

• Wind and Structures
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• v.6 no.2
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• pp.107-126
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• 2003

This paper describes a simple and practical approach through the application of Linear Stochastic Estimation (LSE) to reconstruct wind-induced pressure time series from the covariance matrix for structural load analyses on a low building roof. The main application of this work would be the reduction of the data storage requirements for the NIST aerodynamic database. The approach is based on the assumption that a random pressure field can be estimated as a linear combination of some other known pressure time series by truncating nonlinear terms of a Taylor series expansion. Covariances between pressure time series to be simulated and reference time series are used to calculate the estimation coefficients. The performance using different LSE schemes with selected reference time series is demonstrated by the reconstruction of structural load time series in a corner bay for three typical wind directions. It is shown that LSE can simulate structural load time series accurately, given a handful of reference pressure taps (or even a single tap). The performance of LSE depends on the choice of the reference time series, which should be determined by considering the balance between the accuracy, data-storage requirements and the complexity of the approach. The approach should only be used for the determination of structural loads, since individual reconstructed pressure time series (for local load analyses) will have larger errors associated with them.

• Journal of architectural history
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• v.10 no.3 s.27
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• pp.45-60
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• 2001

The Tongdo temple have been transformed continuously since its first establishment about 1300 years ago. Nevertheless three critical elements specified by 'Jajangyulsa', founder of the temple have not varied over the times but rather strengthened and strongly combined. All elements and doctrines of the religion coexist and form a harmony within the whole of the temple. This researcher examined what changes, or combinations, in spatial formation were sought for such unique structures of the Tongue temple by focusing mainly on the Sangrojun area of the temple to obtain the following findings. First. unlike a work by a Japanese researcher 'Sekino Tadashi', the east yard of the main building was found located on the section line which corresponded to the separation line of Yungkuncheokdo(營建尺度=measure running) from the edge of the Keumkangkyedan(金剛戒壇 =Buddhist platform) embankment to the corner column of the Kamrodang. This was confirmed as a result of the review of photos shown in [Chosun Kojukdobo]. Second, the number of stairs used for the Keumkangkyedan was thought to become three when the temple was firstly restored in 1379 as a result that this researcher reviewed Chinese literature 'DoSun' and [Kyedandokyung(戒壇圖經)], records by 'Lee saek' and 'Jung Shihan', studies of Yungkun measure and actual changes in the temple. Then the temple was forth restored in 1705 when the second of the stairs was changed in area and height and at the same time grounded hard for a space for a Buddhist service. Third, the roof of the main building was probably changed in shape during the Koryo period when the plane structure, furnish arrangement, emphasized front, stone lanterns of the building and political factors of that time were all considered. Fourth, the main building was Initially designed to provide a Buddhist sermon service which was assumedly followed by a similar service at a Keumkangkyedan. Thus the main building had a small window on the northern side which might be opened up to look out or otherwise go outside like a door. However, the window was probably locked up like a surrounding wall since the main building was entirely repaired after the end of Japanese invasion of Korea in 1592.

• Structural Engineering and Mechanics
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• v.65 no.6
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• pp.679-687
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• 2018

In composite materials technology, the fiber-reinforced polymers (FRP) have opened up new horizons in infrastructural engineering field for strengthening existing structures and components of structure. The Carbon fiber reinforced polymer (CFRP) sheets are well suited for RC columns to this application because of their high strength to weight ratio, good fatigue properties and excellent resistance to corrosion. The main focus of present experimental work is to investigate effect of shapes on axial behavior of CFRP wrapped RC columns having same cross-sectional area and slenderness ratio. The CFRP volumetric ratio and percentage of steel are also adopted constant for all the test specimens. A total of 18 RC columns with slenderness ratio four were cast. Nine columns were control and the rest of nine columns were strengthened with one layer of CFRP wrap having 35 mm of corner radius. Columns confined with CFRP wrap were designed using IS: 456:2000 and ACI 440.2R.08 provisions. All the test specimens were loaded for axial compression up to failure and failure pattern for each shaped column was investigated. All the experimental results were compared with analytical values calculated as per the ACI-440.2R-08 code. The test results clearly demonstrated that the axial behavior of CFRP confined RC columns is affected with the change in shapes. The axial deformation is higher in CFRP wrapped RC circular column as compared to square and rectangular columns. Stress-strain behaviour revealed that the yield strength gained from CFRP confinement was significant for circular columns as compare to square and rectangular columns. This behaviour may be credited due to effect of shape on lateral deformation in case of CFRP wrapped circular columns at effective confinement action.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.573-576
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• 2008

Recently, it is the well-known that there are some kinds of problem the waste concrete generated while repairing, reinforcing and dismantling of structures in the domestic and overseas. In this paper, various tests were performed about the use of the recycled concrete fine aggregate for the materials of high quality and structural concrete. And also, in order to improve structural performance of the concrete structure the steel frame was under overcrowded arrangement of steel bar. Consequently, it was be necessary the Self-Consolidating Concrete(SCC) that can fill the concrete into the work-form corner which has become overcrowded arrangement of steel bar without any other vibration. The purpose of this study is related to the properties of Self-Consolidating Concrete(SCC) according to mixing ratio of recycled concrete fine aggregate.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.2
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• pp.124-133
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• 1998

This paper describes a research work of developing a computer-aided design of blanking and piercing for irregular-shaped sheet metal products. An approach to the development of compact and practical CAB system is based on the knowledge-based rules. Knowledge for the CAD system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. The system has been written in AutoLISP on the AutoCAD with a personal computer. Based on knowledge-based rules, the system, STRT-DES, is designed by considering several factors, such as complexities of blank geometry and punch profile, availability of press equipment and standard parts, utilization ratio which minimizes the scrap in a single or a pairwise operation, bridge width, grain orientation and design requirements which maximize the strength of the part when subsequent bending is involved. This system checks a forming feasibility with both internal and external features, a dimension of blanked hole, and a corner and a fillet radius for irregualrly shaped sheet metal products. Therefore this system can carry out a die design for each process which is obtained from results of an automated blank layout drawing with a best utilization ratio for irregular shape of product that was successful in production feasibility check module and those of an automated strip layout drawing and generate part drawings and the assembly drawing of die set in graphic forms.

• Structural Engineering and Mechanics
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• v.57 no.4
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• pp.717-731
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• 2016

In orthopedic surgery and more especially in total arthroplastie of hip, the fixing of the implants generally takes place essentially by means of constituted surgical polymer cement. The damage of this materiel led to the fatal rupture and thus loosening of the prosthesis in total hip, the effect of over loading as the case of tripping of the patient during walking is one of the parameters that led to the damage of this binder. From this phenomenon we supposed that a remain of bone is included in the cement implantation. The object of this work is to study the effect of this bony inclusion in the zones where the outside conditions (loads and geometric shapes) can provoke the fracture of the cement and therefore the aseptic lousing of the prosthesis. In this study it was assumed the presence of two bones -type inclusions in this material, one after we analyzed the effect of interaction between these two inclusions damage of damage to this material. One have modeled the damage in the cement around this bone inclusion and estimate the crack length from the damaged cement zone in the acetabulum using the finite element method, for every position of the implant under the extreme effort undergone by the prosthesis. We noted that the most intense stress position is around the sharp corner of the bone fragment and the higher level of damage leads directly the fracture of the total prosthesis of the hip.

• Transactions of Materials Processing
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• v.16 no.8
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• pp.603-613
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• 2007

This paper is concerned with joining of thin metal sheets by single stroke clinching process. This method has been used in sheet metal work as it is a simple process and offers the possibility of joining similar-dissimilar thin sheet metals. Clinching generates a joint by overlapping metal sheets deforming plastically by punching and squeezing sequence. AA 5754 aluminum alloy of 0.5 mm thick sheets have been selected as a modal material and the process has been simulated under different process conditions and the results have been analyzed in terms of the quality of clinch joints which are influenced mainly by tool geometries. The rigid-plastic finite element method is applied to analyses in this paper. Analysis is focused mainly on investigation of deformation and material flow patterns influenced by major geometrical parameters such as die diameter, die depth, groove width, and groove corner radius, respectively. To evaluate the quality of clinch joints, four controlling or evaluation parameters have been chosen and they are bottom, neck thickness of bottom and top sheets, and undercut thickness, respectively. It has been concluded from the simulation results that the die geometries such as die depth and diameters are the most decisive process parameters influencing on the quality of clinch joints, and the bottom thickness is the most important evaluation parameter to determine if the quality of clinch joints satisfies the demand for industrial application.

• The Journal of the Korea Contents Association
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• v.18 no.1
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• pp.587-595
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• 2018

This research aims to analyze the importance-performance among multiplex cinema selection attributes. Therefore, we collected data for visitors who visited the multiplex cinema and want to watch movies. Of the various multiplex cinema selection attributes, four factors were deduced that includes: major services, human services, physical environment, auxiliary services using exploratory factor analysis. In the quadrant I, the area of 'Concentrate Here' was 'diversity of screening time', 'diversity of movie genre', 'convenience of mobile app use', 'size and convenience of parking facility'. In the quadrant II, 'Keep up the Good Work' area was 'convenience of website booking', 'discounts through card partnerships', 'employee friendliness', 'accurate employee information delivery', 'comfortable seating', 'screen size', 'cinematic sound quality', and 'convenience of traffic' etc. The quadrant III, 'Low Priority' appeared to be 'membership system', 'tidiness of staff attire', 'resting space for waiting time', 'accessibility to the neighboring area', 'diversity of the snack corner', and 'overall cleanliness' etc. The quadrant IV, 'Possible Overkill' was 'appropriateness of the auditorium temperature' and 'service proficiency'.

• Korean Journal of Oriental Medicine
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• v.15 no.2
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• pp.85-91
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• 2009

The manufacture date of the number 198 wooden tablet excavated at Anapji is estimated to be between year 751 and 774. As medical artifacts around this period of time is scarce, the discovery of an artifact with distinct medical information such as names of medicinal drugs recorded in hand writing holds great value in the history of medicine. This wooden tablet was presumably a prescription for a medicinal formula. That the '灸' character which is a method of processing drugs is found after '甘草' indicates the possibility of this wooden tablet to be a practical form of prescription. On this slip, a certain sign can be found at the upper right corner of the names of drugs. This is thought to be an additional sign added to the original text. It seems to have been originated from the letter '了', based on the composition and finishing touches of the strokes, presumably to confirm the end of a work by adding the letter '了' which means 'to finish'. The base material of 靑黛 and 藍淀 are the same, and the two often took each other's place in a prescription. It is difficult to find an example of a formula where both drugs are included. Therefore, the prescription on the front with 靑黛, and the one on the back with 藍淀 of tablet 198 can be understood as separate formulas.