• Smart Structures and Systems
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• v.21 no.4
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• pp.521-535
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• 2018

The main purpose of this paper is to predict missing absolute out-of-plane displacements and failure limits of infill walls by artificial neural network (ANN) models. For this purpose, two shake table experiments are performed. These experiments are conducted on a 1:1 scale one-bay one-story reinforced concrete frame (RCF) with an infill wall. One of the experimental models is composed of unreinforced brick model (URB) enclosures with an RCF and other is composed of an infill wall with bed joint reinforcement (BJR) enclosures with an RCF. An artificial earthquake load is applied with four acceleration levels to the URB model and with five acceleration levels to the BJR model. After a certain acceleration level, the accelerometers are detached from the wall to prevent damage to them. The removal of these instruments results in missing data. The missing absolute maximum out-of-plane displacements are predicted with ANN models. Failure of the infill wall in the out-of-plane direction is also predicted at the 0.79 g acceleration level. An accuracy of 99% is obtained for the available data. In addition, a benchmark analysis with multiple regression is performed. This study validates that the ANN-based procedure estimates missing experimental data more accurately than multiple regression models.

• The Journal of the Korean bone and joint tumor society
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• v.1 no.2
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• pp.244-248
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• 1995

Glomus tumor is uncommon tumor with an incidence of about 1% in soft tissue tumors and the single most common location is the subungual region of the finger. Many reports have emphasized that glomus tumors were difficult to diagnose and that the result of surgical removal was good, but nail deformity has received little attention. Most of authors removed the entire nail or partially splitted the nail to exposure the nail bed and tumor. Nobody reported whether nail deformity after operation was present or not. But, an abnormal nail is both a cosmetic and a functional problem in that catches on objects. In this study, our attention was postoperative nail deformity as well as the results of surgical removal. Seven patients(eight cases) who were diagnosed as a subungal glomus tumor in the hand were treated by surgical excision without removal of the nail and followed over twenty two months. And then we report on our experience with 8 cases of subungual glomus tumor which were successfully treated by complete excision without nail deformity.

• Journal of Korean Neurosurgical Society
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• v.40 no.5
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• pp.384-386
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• 2006

Acute subdural hematoma is an exceptionally rare, but life-threatening complication of spinal anesthesia. The authors report here on a case of acute subdural hematoma in a 52-year-old male who underwent an arthroscopic knee joint operation under spinal epidural anesthesia due to tearing of the medial meniscus. He complained of headache after surgery. Computed tomography[CT] revealed acute subdural hematoma in the right fronto-tempo-parietal area. The headache progressed in spite of analgesics and bed rest; two weeks later, the CT showed subacute subdural hematoma with a mass effect. The patient improved after surgical decompression. The pathogenesis of subdural hematoma formation after dural puncture is discussed and we briefly review the relevant literature. Prolonged and severe postdural puncture headache[PDPH] should be viewed with suspicion and investigated promptly to rule out any intracranial complications. Immediate treatment of the PDPH with an epidural blood patch to prevent further CSF leakage should be considered.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.127-133
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• 2018

The Saemangeum master plan includes dredging and waterproofing materials, construction projects that can change the hydraulic characteristics of the Saemangeum and Mangyeong and Dongjin River basins. In this study, the river safety of 2030 when the Saemangeum master plan was completed for 100 year frequency, 500 year frequency and 100 year frequency applied RCP 8.5 scenario was examined using Delft3D. As a result of the analysis, it was confirmed that there was no overflowing point at the 100 year frequency, but the difference between the flood level and the river bank elevation was relatively small at the curved and river joint part. At the 100-year frequency with the 500-year frequency and the RCP 8.5 scenario, the possibility of overflowing at several locations was confirmed. The possibility of river bed loss due to fast velocity appears in the upstream part of Mankyung River and it is necessary to monitor the safety of hydraulic structures continuously. In addition, it is expected that the expansion of the area showing the characteristics of the lake due to dredging will affect the sediment mechanism and water quality, so detailed and diverse studies will be needed.

• Journal of the Korea Furniture Society
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• v.28 no.2
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• pp.126-134
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• 2017

This study explores PyeongSang, a piece of traditional Korean furniture, in order to make people know the details about what the piece is in the first paper. And based on the paper, PyeongSang will be developed as moulded multi-useful beds and sofas adapting the joint and ornament from the structure and pattern of the piece in the next paper. As the result, it appeared as two styles such as bed types mentioned as SalPyeongSang and ttulmaru in Korean. The pieces have been used from the three Kingdoms period in Korean history. The styles appeared as the structure of four parts with the lower fences called as nangan, the seats jointed by thin wood pieces, the wind hole, and the legs of foot types. The parts were beautifully carved with the ornament such as lattice patterns like geokjamun and manjamun, flower patterns like dangchomun, elephant eyes patterns like ansangmun from the Korean tradition. And the legs showed various shapes such as supports transformed from horse foots, tiger legs and bamboo, and board types carved with elephant eyes and geometric patterns. Hence, in the next paper based on this paper, PyeongSang will be developed as moulded multi-useful beds and sofas adapting the joints and ornaments from the structure and patterns of the piece.

• Advances in concrete construction
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• v.8 no.2
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• pp.77-90
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• 2019

This paper aims to investigate vibration frequency decrease (vibration period elongation) of reinforced concrete (RC) structure with unreinforced infill wall and reinforced infill wall exposed to progressively increased artificial earthquake load on shaking table. For this purpose, two shaking table experiments were selected as a case study. Shaking table experiments were carried on 1:1 scaled prototype one bay one storey RC structure with infill walls. The purpose of this shaking table experiment sequence is to assess local behavior and progressive collapse mechanism. Frequency decrease and eigen-vector evolution are directly related to in-plane and out-of-plane bearing capacities of infill wall enclosure with reinforced concrete frame. Firstly, frequency decrease-damage relationship was evaluated on the base of experiment results. Then, frequency decrease and stiffness degradation were evaluated with applied Peak Ground Acceleration (PGA) by considering strength deterioration. Lastly, eigenvector evolution-local damage and eigenvector evolution-frequency decrease relationship was investigated. Five modes were considered while evaluating damage and frequency decrease of the tested specimens. The relationship between frequency decrease, stiffness degradation and damage level were presented while comparing with Unreinforced Brick Infill (URB) and Reinforced Infill wall with Bed Joint Reinforcement (BJR) on the base of natural vibration frequency.

• Computers and Concrete
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• v.23 no.2
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• pp.97-106
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• 2019

This paper describes the design of a new interlocking masonry system, the production of designed interlocking units and mechanical properties of interlocked masonry assemblages with mortar. In this proposed system, units have horizontal and vertical locks to integrate the units to the wall and have a channel to enable the use of horizontal reinforcements in the wall. Using these units, unfilled, filled or reinforced walls can be constructed with or without mortar. In the production of the interlocking units, it was decided to use foamed concrete. 12 trial productions have been carried out at different mix proportions to obtain the optimum concrete mix. At the end of the mentioned productions, the units were produced with foam concrete which is selected as the most suitable in terms of compressive strength and specific gravity. Then, axial compression, diagonal tension and bed joint shear tests were carried out to determine the mechanical properties of the interlocked masonry assemblages with mortar. Results from the tests showed that interlocks designed to strengthen the system against shear stresses by creating discontinuity throughout the joints have been successful to achieve their aim. Obtained data will enable structural analysis of walls to be constructed with these new units.

• Journal of the Earthquake Engineering Society of Korea
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• v.26 no.1
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• pp.1-11
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• 2022

In this study, the seismic performance of a two-story unreinforced masonry (URM) building was assessed following the linear and nonlinear static procedures specified in the seismic evaluation guideline of existing buildings. First, the provisions to assess failure modes and shear strengths of URM walls and wall piers were reviewed. Then, a two-story URM building was assessed by the linear static procedure using m-factors. The results showed that the walls and wall piers with aspect ratios h_e // (i.e., effective height-to-length ratio) > 1.5 were unsafe due to rocking or toe crushing, whereas the walls with h_e // ≤ 1.5 and governed by bed-joint sliding mainly were safe. Axial stresses and shear forces acted upon individual masonry walls, and wall piers differed depending on whether the openings were modeled. The masonry building was reevaluated according to the nonlinear static procedure for a more refined assessment. Based on the linear and nonlinear assessment results, considerations of seismic evaluation for low-rise masonry buildings were given with a focus on the effects of openings.

• Journal of Astronomy and Space Sciences
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• v.32 no.4
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• pp.357-366
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• 2015

By using the Optical Wide-field Patrol (OWL) network developed by the Korea Astronomy and Space Science Institute (KASI) we generated the right ascension and declination angle data from optical observation of Low Earth Orbit (LEO) satellites. We performed an analysis to verify the optimum number of observations needed per arc for successful estimation of orbit. The currently functioning OWL observatories are located in Daejeon (South Korea), Songino (Mongolia), and Oukaïmeden (Morocco). The Daejeon Observatory is functioning as a test bed. In this study, the observed targets were Gravity Probe B, COSMOS 1455, COSMOS 1726, COSMOS 2428, SEASAT 1, ATV-5, and CryoSat-2 (all in LEO). These satellites were observed from the test bed and the Songino Observatory of the OWL network during 21 nights in 2014 and 2015. After we estimated the orbit from systematically selected sets of observation points (20, 50, 100, and 150) for each pass, we compared the difference between the orbit estimates for each case, and the Two Line Element set (TLE) from the Joint Space Operation Center (JSpOC). Then, we determined the average of the difference and selected the optimal observation points by comparing the average values.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.893-901
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• 2023

The International Association Marine Aids to Navigation and Lighthouse Authorities (IALA) proposed guidelines for VTS manual operation in 2016 for safe and efficient operation of ship. The Korea Coast Guard (KCG) established and operated 19 VTS centers in ports and coastal waters across the country by 2022 based on the IALA VTS manual and VTS operator's education and training guidelines. In addition, IALA proposed the Inter-VTS Exchange Format (IVEF) Service recommendation (V-145), a standard for data exchange between VTS, in 2011 for efficient e-Navigation system services and safe and efficient VTS service support by VTS authorities. The IVEF service in a common framework for ship information exchange, and it presents seven basic IVEF service (BISs) models. VTS service providers can provide safer and more efficient VTS services by sharing VTS information on joint area using IVEF standards. Based on the BIS data, interaction, and interfacing models, this paper introduced the development of the cloud-based VTS integration services performed by the KCG and the results of the VTS integration platform test-bed for IVEF service implementation. In addition, the results of establishing a cloud VTS integrated platform test-bed for the implementation of IVEF service and implementing the main functions of IVEF service were presented.