• The Journal of Korean Orthopaedic Ultrasound Society
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• v.7 no.1
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• pp.39-44
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• 2014

The patellar clunk syndrome is one of the patellofemoral complication, caused by formation of the fibrous nodule at the suprapatellar region after total knee arthroplasty. The symptom involves painful catching, crepitus and clunk during knee extension. It has been mainly but not exclusively associated with the posterior stabilized total knee system. The fibrous nodule is entrapped in the femoral intercondylar notch of the femoral component during flexion and as the knee is extended, it displaces back to the trochlear groove abruptly and the typical symptoms occur. The risk of developing this complication is primarily related to the design of the femoral component and higher incidence was noted with earlier designs of posterior stabilized knee prosthesis. Modifications have been made to the femoral component to optimize the kinematics of the patellofemoral joint and thereby reduced the incidence of patellar clunk syndrome but did not eliminate the problem completely. Clinical examination is the gold standard of diagnosis and imaging study has been used as a possible adjunct to diagnosis. Especially ultrasonography is an imaging modality, which can be easily performed to detect the fibrous nodule on the quadriceps tendon. We report a case of patellar clunk syndrome which was diagnosed with ultrasonography.

• Journal of the Korean Institute of Gas
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• v.17 no.5
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• pp.64-68
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• 2013

Non destructive testing(NDT) methods of electrofusion(EF) joints of thermoplastics pipes are required for fusion joint safety and for the long term reliability of a pipe system. Electrofusion joints, which are joined at the proper fusion process and procedures, may encounter defects due to the difference of ovality between pipes and coupling, improper fusion process or porosity result from electrofusion joining. These defects can cause the failure of pipeline and by extension, they can be caused the limit to expand the use of plastics pipes. This paper studies inspection results using ultrasonic imaging method for damaged polyethylene electrofusion joints. Gas was leaking from 250mm diameter polyethylene electrofusion joints at February 2004 which was electrofused at December 1994 and operation pressure was 2.45kPa. First, surface inspection was conducted and then in order to find the types of defects examination using ultrasonic imaging method was performed. Lack of fusion and inappropriate inserting for polyethylene pipes into electrofusion coupling were found and causes of the gas leak were judged that misalignment and insert defect. Cutting inspection was performed and each inspection results were compared to. Results of ultrasonic imaging method and cutting inspection were the same.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.5
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• pp.347-355
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• 2000

To determine nitrogen balance (Input-Output) of Korea that was asked by Joint Working Party of the Committee for Agriculture and the Environment Policy Committee, OECD, nitrogen input and output were separately investigated as followings: nitrogen input included the amounts of chemical fertilizer consumption, cattle manure production, and biological nitrogen fixation in the national scale, and nitrogen output summed amounts withdrawn by crop and pasture harvesting, and crop residue removal, and lost by denitrification. In 1997, nitrogen balance of Korea was $158kg\;ha^{-1}$ and $211kg\;ha^{-1}$ on including and excluding denitrification loss, respectively. N balance excluded N loss by denitrification and N withdrawal by crop residues on nitrogen output was $250kg\;ha^{-1}$, which OECD asked to except two items from N balance determination because participants were not enough their data. Nitrogen balance was increased to 1.7~2.3 times in 1997 compared with 70 and $162kg\;ha^{-1}$ in 1985, which calculated on the condition of including denitrification and excluding denitrification and removal of crop residues in nitrogen output, respectively. This increase was caused mainly by increasing livestock manure production and chemical fertilizer consumption together with agricultural land area decrease. Nitrogen input was composed with 59% of chemical fertilizer. 42% of cattle manure and 5% of others in 1997, and output was with 73% of crop production, 23% of crop residue withdrawal and 4% of pasture production. Average nitrogen balance excluded N loss by denitrification and N withdrawals by crop residues in 1995~1997 calculated by OECD was $253kg\;ha^{-1}$, which was the second highest rank in OECD participants following $262kg\;ha^{-1}$ of Netherlands. Japanese N balance that has similar farming system with us was $135kg\;ha^{-1}$.

• Journal of Korean Society of Transportation
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• v.19 no.6
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• pp.89-102
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• 2001

Using a multiproduct translog cost function model, this paper examines the existence or absence of scale and scope economies in Seoul's urban bus industry. The Paper then conceptualizes that the bus firm produces three outputs (city, seat and local bus-kilometers) using low input factors(labor, capital, fuel and maintenance). Using 1996 annual observations for 81 Seoul's bus firms, the equation system consisting of a cost function and three input share equations is estimated with the nonlinear iterative Zellner method. The findings show that the cost function corresponding to a non-homothetic production technology with separability between local bus outputs and inputs adequately represents the structure of cost for Seoul's bus firms, and that the demand lot all input factors is quite inelastic with respect to their own price. On the other hand, nearly all firms experience mild overall economies or scale, but rather marked product-specific economies of scale with respect to all the three outputs. In addition, there appear to be substantial economies or scope associated with the joint production of city and seat bus services, while considerable diseconomies of scope associated with that of city and local bus services. These results indicate that the merger of smaller firms into larger firms with a fleet of approximately 200 buses would result in more cost-efficient bus services.

• Journal of Korean Society of Transportation
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• v.22 no.6
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• pp.159-173
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• 2004

Using a generalized translog multiproduct cost function model, this paper examines economies of scale and scope in the vertically-integrated Korean railway industry. The paper then conceptualizes that the Korea National Railroad (KNR) produces four outputs (passenger-kilometers, ton-kilometers of freight, average length of passenger trips, and average length of freight haul) using three input factors(labor, fuel and maintenance, and rolling stock and capital). Using time series data collected from the KNR's annual records for the years from 1977 to 2002, the simultaneous equation system consisting of a cost function and two input share equatins is estimated with the Zellner's iterative seemingly unrelated regression. The findings show that the cost function corresponding to a non-Cobb-Douglas, non-homothetic, and non-homogeneous production technology adequately represents the KNR's cost structure. On the other hand, the Korean railway industry experiences sizeable overall scale economies, which result from substantial product-specific scale economies associated with passenger-kilometers and freight ton-kilometers and from scope economies associated with their joint production. In addition, the magnitude of economies of scope is influenced largely by the ratio of passenger trips, and has increased over time as the former has increased while the latter has decreased.

• Korean Journal of Construction Engineering and Management
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• v.19 no.5
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• pp.10-21
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• 2018

This study analyzes difficulties of enterprise activities in Chinese construction market by surveys on early entrants and interviews with experts. This study also suggests future strategy to enter the market by using inducement coefficient model. Korean construction companies in China are under heavy pressure to maintain requirement of licenses, despite recent deregulation. They are in dire predicament for market entry due to the Foreign Direct Investment System. It is almost impossible to participate in public projects and also it is not easy to do PPP projects. Therefore, Korean government should make more efforts to solve those issues through negotiations in FTA and GPA. For future expansion in Chinese construction market, it is highly recommended to boost cooperation models between Korea and China according to the empirical results of inducement coefficient model. Korean companies should collaborate with Chinese companies in some fields: smart city, environment and water treatment. Also, Korean government should support Korean companies by diplomatic means such as requesting for further opening of China's market. In GPA or GATS negotiation, Korean government should ask Chinese government that Korean companies can obtain order independently (without joint venture with Chinese companies) in China. Lastly, Korean construction companies should participate in construction projects ordered by international organizations such as ADB, AIIB.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.5
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• pp.333-340
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• 2019

Tests using a middle velocity propulsion impact machine (MVPIM) were performed to verify the impact resistance capability of sandwich concrete panels (SCP) in a modular liquefied natural gas (LNG) outer tank, and numerical models were constructed and analyzed. $2{\times}2m$ specimens with plain sectional characteristics and specimens including a joint section were used. A 51 kg missile was accelerated above 45 m/s and impacted to have the design code kinetic energy. Impact tests were performed twice according to the design code and once for the doubled impact speed. The numerical models for simulating impact behaviors were created by LS-DYNA. The external steel plate and filled concrete of the panel were modeled as solid elements, the studs as beam elements, and the steel plates as elasto-plastic material with fractures; the CSCM material model was used for concrete. The front plate deformations demonstrated good agreement with those of other tests. However the rear plate deformations were less. In the doubled speed test for the plain section specimen, the missile punctured both plates; however, the front plate was only fractured in the numerical analysis. The impact energy of the missile was transferred to the filled concrete in the numerical analysis.

• The Korean Journal of Archival Studies
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• no.30
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• pp.175-204
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• 2011

Electronic records are generated not only in public sector but also in private sector. Records will be used across the public-private boundary. The Certified e-Document Authorities(CeDAs) may keep electronic documents in private sector for preservation and evidence, like the official Record Management Systems for Public sector. A CeDA is the Trusted Third Party (TTP) as a business to be entrusted and proof interchanging documents between parties. This CeDA system could be sustainable only if the CeDA earn the enough sales through enough uses. And yet, all the eight CeDA companies have not had enough users. How to utilize CeDAs is one of the hot issues in this area. In this paper, We analyze the threat to trustworthiness of CeDA due to payment of only one party among others, and describe the difficulty in use of CeDA for an individual user. These things make CeDAs cannot have enough users. To do address these, We expand the boundary of relevant parties for a document, present a delegate-establishing option under a joint name, show the needs of identifying and notifying minimum relevant parties, and suggest the proxy parties to help the individual users.

• Journal of the Korean earth science society
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• v.42 no.2
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• pp.185-194
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• 2021

A lava dome and sheet lava flow can be observed at the seashore of Aewol, Jeju island. The cylindrical lobes are characterized by a concentric structure consisting of a massive core and radial joints. Columnar joints with different thickness between the upper and lower parts are developed in the sheet lava flow around the rock salt field in Goeomri. The upper part of the columnar joints is uneven in shape, and has a diameter of 120-150 cm. The lower part of the columnar joints is hexagonal and pentagonal in shape, and has a diameter of about 60 cm. The cylindrical lobes can be divided into two groups based on size and shape. One is a megalobe, with a semicircular outline and a maximum diameter of 30 m. The other is a circular lobe with a diameter of less than 10 m. The columns in the radial joints have hexagonal and pentagonal cross sections and gradually increasing diameter, outward from the core, to a size of 80-120 cm at the rim. The concentric structure observed in the cylindrical lavas is attributable to a combination of four factors. The first is a circular crack caused by the decrease of the temperature and density difference between the inside and outside of the cylindrical lava flow. The second is a concentric chisel mark of the radial joints, which formed at the same time as the radial joints. The third is a flow band, which is a trace left in a round passage when lava flows through. The fourth is a vesicular band formed in a cave by gas bubbles escaping from the lava flow.

• Journal of Broadcast Engineering
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• v.26 no.3
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• pp.269-282
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• 2021

As the distribution of 3D content such as augmented reality and virtual reality increases, the importance of real-time computer animation technology is increasing. However, the computer animation process consists mostly of manual or marker-attaching motion capture, which requires a very long time for experienced professionals to obtain realistic images. To solve these problems, animation production systems and algorithms based on deep learning model and sensors have recently emerged. Thus, in this paper, we study four methods of implementing natural human movement in deep learning model and kinect camera-based animation production systems. Each method is chosen considering its environmental characteristics and accuracy. The first method uses a Kinect camera. The second method uses a Kinect camera and a calibration algorithm. The third method uses deep learning model. The fourth method uses deep learning model and kinect. Experiments with the proposed method showed that the fourth method of deep learning model and using the Kinect simultaneously showed the best results compared to other methods.