• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.133-144
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• 2003

The resonant column testing is a laboratory testing method to determine the shear modulus and material damping factor of soils. The method has been widely used for many applications and its importance has increased. Since the first use of the testing method in 1960's, the low-technology electronic devices fir testing and data acquisition have limited the measurement only to the amplitude of the linear spectrum. The limitations of the testing method are also attributed to the assumption of linear-elastic material in the theory of the resonant column testing and also to the incomplete understanding of the dynamic behaviour of the resonant column testing device. Recently, Joh et al. proposed a theory to overcome the limitations of the resonant column testing by deriving the equation of motion and providing its solution for the resonant column testing device. This study proposed the improved data reduction and analysis method for the resonant column testing, thanks to the advanced data acquisition system and the new theoretical solution for the resonant column testing system. For the verification of the proposed data reduction and analysis method, the numerical simulation of the resonant column testing was performed by the finite element analysis. Also, a series of resonant column testing were performed fir Joomunjin sand, which verified the feasibility of the proposed method and revealed the limitations of the conventional data reduction and analysis method.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.8
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• pp.3403-3410
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• 2014

Context: Interest exits in whether TNF-alpha antagonists increase the risk of breast cancer and total malignancies in patients with rheumatoid arthritis (RA). Objectives: To analyze the risk of malignancies, especially breast cancer, in patients with RA enrolled in randomized control trials (RCTs). Methods: A systematic literature search for RCTs from 1 January 1998 to 1 July 2013 from online databases, such as PubMed, WILEY, EMBASE, ISI web of knowledge and Cochrane Library was conducted. Studies included RCTs that compared the safety of at least one dose of the five TNF-${\alpha}$ antagonists with placebo or methotrexate (MTX) (or TNF-${\alpha}$ antagonists plus MTX vs placebo plus MTX) in RA patients for more than 24 weeks and imported all the references into document management software EndNote${\times}6$. Two independent reviewers selected studies and extracted the data about study design, patients' characteristics and the type, number of all malignancies. Results: 28 RCTs from 34 records with 11,741 patients were analyzed. Of the total, 97 developed at least one malignancy during the double-blind trials, and breast cancer was observed in 17 patients (17.5% of total malignancies). However, there was no statistically significant increased risk observed in either the per protocol (PP) model (OR 0.65, 95%CI [0.22, 1.93]) or the modified intention to treat (mITT) model (OR 0.75, 95%CI [0.25, 2.21]). There were also no significant trend for increased risk of total malignancies on anti-TNF-${\alpha}$ therapy administered at approved doses in either model (OR, 1.06, 95%CI [0.64, 1.75], and OR, 1.30, 95%CI [0.80, 2.14], respectively). As to the two models, modified intention to treat model analysis led to higher estimation than per protocol model analysis. Conclusions: This study did not find a significantly increased risk of breast cancer and total malignancies in adults RA patients treated with TNF-${\alpha}$ antagonists at approved doses. However, it cannot be ignored that more patients developed malignancies with TNF-${\alpha}$ antagonists therapy compared with patients with placebo or MTX, in spite of the lack of statistical significance, so that more strict clinical trials and long-term follow-up are needed, and both mITT and PP analyses should be used in such safety analyses.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.69-78
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• 2013

A Korean MP3player also has become complex multimedia device which can provide various functions such as DMB, image playback, radio, electronic dictionary, storage device, and Internet. However, these functions are not provided through one-time mediation. Therefore, studying which changes were made for obtaining or installing these functions and what made such changes possible will be a basis to approach the change factors of medium through medium. Ultimately, by enabling to access the factors of cultural and social changes through MP3player, the main point of this study, it will be a methodological attempt to study a social aspect through medium. This study approached re-mediation according to the genealogical change of MP3player. This study researched the change of media through mediation of MP3player, and approached the change in social contextuality through this. The factors for which a medium is changed are various, but in the change of MP3 player there is re-mediation of each medium in addition to technical change. That is, it is deemed that there are 're-mediation among devices' and 'socially contextual re-mediation' in the change through re-mediation of MP3player.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.153-162
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• 2017

Weapon systems have been developed with high technology electronic equipment due to technology growth. In addition, the capital, operational and maintenance costs of weapon systems have all increased. However, cost of operation and maintenance for weapon systems has been decreased relatively compared to the increased capital cost of weapon systems. Therefore, the defense industry needs to research the life cycle cost of weapon systems that have high operational and maintenance costs. This paper focuses on maintenance equipment for the operation and maintenance of weapon systems. Recently, it seems that the weapon systems that have periodic calibration with maintenance equipment are valid. The equipment requires periodic calibration by the manufacturer to check its own validation. Basically, customers demand high reliability devices from foreign companies that have qualified in the global market. Therefore, the tools need to be calibrated overseas. In other words, weapon systems are not available when the equipment has to be calibrated overseas because the systems require validation with valid maintenance equipment. A purpose of this paper is to compare the loss costs that arise from the calibration of the equipment overseas and the purchasing cost of the tools. Finally, the research shows the number of equipment that customers need to minimize the cost. This research will help to improve the efficiency of operation of weapon systems and solve the problems associated with the need for maintenance overseas.

• The KIPS Transactions:PartD
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• v.13D no.2 s.105
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• pp.271-278
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• 2006

This paper presents industry feedback and a case of improvement trial on enabling reuse driven software development which is one of several activities to improve software quality and productivity in a company which develops software that are embedded into consumer electronic products. Several case studies will be introduced that are related to software reuse strategies and practices to show how to establish environment for reuse basis in a company, how to apply it to development team and project and how to improve that through trials and errors. To enable reuse-oriented software development in a huge company, integrated and focused approach is needed among technical, management and environmental point of view. We tried to solve that problem in technical field with reuse method, in management filed with reuse metric and in environment field with reuse repository. The characteristics of our software development environment could be summarized as below. The first, embedded software which would not independent to hardware devices and the second, it is very huge company which develops extremely various products by many different organization with different domain characteristics and the third, development lead time is extremely short and many variation models are stems from basic models. We expect that our study would give contribution to industry struggling to solve similar problem for presenting our experience and could be a reference model for enabling software reuse in a real world practically.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.596-601
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• 2020

Silicon carbide is considered a potentially useful material for high-temperature electronic devices because of its large band gap energy and p-type or n-type conduction that can be controlled by impurity doping. Accordingly, the thermoelectric properties of -SiC powder prepared by refined diatomite were investigated for high value-added applications of natural diatomite. -SiC powder was synthesized by a carbothermal reduction of the SiO₂ in refined diatomite using carbon black. An acid-treatment process was then performed to eliminate the remaining impurities (Fe, Ca, etc.). n-Type semiconductors were fabricated by sintering the pressed powder at 2000℃ for 1~5h in an N2 atmosphere. The electrical conductivity increased with increasing sintering time, which might be due to an increase in carrier concentration and improvement in grain-to-grain connectivity. The carrier compensation effect caused by the remaining acceptor impurities (Al, etc.) in the obtained -SiC had a deleterious influence on the electrical conductivity. The absolute value of the Seebeck coefficient increased with increasing sintering time, which might be due to a decrease in the stacking fault density accompanied by grain or crystallite growth. On the other hand, the power factor, which reflects the thermoelectric conversion efficiency of the present work, was slightly lower than that of the porous SiC semiconductors fabricated by conventional high-purity -SiC powder, it can be stated that the thermoelectric properties could be improved further by precise control of an acid-treatment process.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.49-61
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• 2011

In recent, library is considered as an integrated knowledge convergence center that can respond to various requests about information service of users. Therefor it is necessary to establish a novel information system based on information communications technologies of the era. In other words, it is currently required to develop mobile information service available in portable devices such as smart phones or tablet PCs, and to establish information system reflecting cloud computing, SaaS, Annotation, and Library 2.0 etc. In this paper we design and implement a library information system using collective intelligence and cloud computing. This information system can be adapted for the varieties of mobile service paradigm and abruptly increasing amount of electronic materials. Advantages of this concept model are resource sharing, multi-tenant supporting, configuration, and meta-data supporting etc. In addition it can offer software on-demand type user services. In order to test the performance of our system, we perform an effectiveness analysis and TTA authentication test. The average response time corresponding to variance of data reveals 0.692 seconds which is very good performance in timing effectiveness point of view. And we detect maturity level-3 or 4 authentication in TTA tests such as SaaS maturity, performance, and application programs.

• Journal of radiological science and technology
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• v.28 no.4
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• pp.307-315
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• 2005

In the ubiquitous computing environments, ICT industries of current society are developed in enormous growth. Medicine or patients with mobile devices can access at any time, any place. The medical procedures at the patient bedside are out of the scope of current systems, which means that patient record and image data access during the medical visit or the execution, recording and confirmation of the medicine prescriptions, still do not enjoy computerized support. Today, the exchange of medical images and clinical information is well defined by DICOM and HL7 standards. The DICOM independent terminal equipment image access system was developed in which a DICOM Engine acts as the gateway between a PACS DB and user's terminal. Implementation system is compatible with most currently available Integration system models. This paper presents a software technology where the medical and nursing staff will be equipped with any device connected by wire and wireless to a central server that provides access to the electronic patient records and that will actively inform about tasks pending distribution. The prototype described in this article implements a medical images and structured reports server that makes the search and recovery of data stored in the DICOM standard possible.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.429-434
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• 2016

This study was performed in order to identify the relation between bone nineral density and life styles of some of Korean colleage students. A total of 121 college students were assessed through bone mineral density test on femoral neck and lumbar spine using dual energy X-ray absorptiometry(DEXA). The survey about their lifestyles with a self-rating questionnaire, was conducted from September 2014 to November 2014. SPSS 18.0 Program was used for those research data analyses such as the frequency analysis, the cross analysis. The percentage of the osteoporisis, osteopenia and normal groups were 0.0%, 24.8% and 75.2%. BMI, Regular menstrual cycle, Walking and Regular exercise in adolescence were positively related with T-score. But Using time of electronic devices was negative related with T-score. It can be concluded that desirable life style in time of college students and adolescence is important for their bone health. The necessity of preparing guideline for preventing bone disease in old age connected with the school curriculum should be recognized to the public and educational authorities.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.250-250
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• 2012

Recently, multiferroic materials have attracted much attention due to their fascinating fundamental physical properties and potential technological applications in magnetic/ferroelectric data storage systems, quantum electromagnets, spintronics, and sensor devices. Among single-phase multiferroic materials, $BiFeO_3$, in particular, has received considerable attention because of its very interesting magnetoelectric properties for application to spintronics. Enhanced ferromagnetism was found by Fe-site ion substitution with magnetic ions. In this study, $BiFe_{1-x}Ni_xO_3$ (x=0 and 0.05) bulk ceramic compounds were prepared by solid-state reaction and rapid sintering. High-purity $Bi_2O_3$, $Fe_3O_4$ and NiO powders were mixed with the stoichiometric proportions, and calcined at $450^{\circ}C$ for 24 h to produce $BiFe_{1-x}Ni_xO_3$. Then, the samples were directly put into the oven, which was heated up to $800^{\circ}C$ and sintered in air for 20 min. The crystalline structure of samples was investigated at room temperature by using a Rigaku Miniflex powder diffractometer. The Raman measurements were carried out with a Raman spectrometer with 514.5-nm-excitation Ar+-laser source under air ambient condition on a focused area of $1-{\mu}m$ diameter. The field-dependent magnetization and the temperature-dependent magnetization measurements were performed with a vibrating-sample magnetometer. The x-ray diffraction study demonstrates the compressive stress due to Ni substitution at the Fe site. $BiFe_{0.95}Ni_{0.05}O_3$ exhibits the rhombohedral perovskite structure R3c, similar to $BiFeO_3$. The lattice constant of $BiFe_{0.95}Ni_{0.05}O_3$ is smaller than of $BiFeO_3$ because of the smaller ionic radius of Ni3+ than that of Fe3+. The field-dependent magnetization of $BiFe_{0.95}Ni_{0.05}O_3$ exhibits a clear hysteresis loop at 300 K. The magnetic properties of $BiFe_{0.95}Ni_{0.05}O_3$ were improved at room temperature because of the existence of structurally compressive stress.