• Transactions of Materials Processing
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• v.23 no.8
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• pp.489-494
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• 2014

Micro forming is an appropriate process to manufacture very small metal parts which can be employed in the field of electronic devices or electrically controlled mechanical systems. The purpose of the current study was to investigate the influences of both blankholding force and blank diameter for the deep drawing of very small cups. It is essential to control the blankholding force because improper force can result in defects such as wrinkles in the flange or cracks in the corner of the drawn cups. In the current study blankholding force was controlled by springs connected to the blankholder of a press die. Exchangeable bushing dies with various die-corner radii were also used. To obtain the limit drawing ratio for each working condition several sizes of circular specimens were prepared using blanking tools. Beryllium copper(C1720) alloy sheet of $50{\mu}m$ thickness was chosen for the experiments. The maximum limit drawing ratio of 2.1 was achieved experimentally for the conditions of the blankholder force(BHF)=5.3kgf and Rd=0.3mm. Both thickness and hardness along the central section of drawn cups were measured and compared for different drawing conditions. It was found that the deviation of measured data in the thickness and hardness distribution increases with increasing blankholder force and blank diameter.

• Proceedings of the Korea Information Assurance Society Conference
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• 2004.05a
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• pp.297-302
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• 2004

Internet becomes absolutely necessary tools due to rapid progress of information technology. Educational correspondence abount an age of information demand is a education focused on a learner and remote education based on information technology. WBI(Web Based Instruction) is a formation that remotly educate a learner using web, possible mutual reaction between instructor and learner, submint various studying material, has a good point to overcome spatial restriction. Internal and external standardization working is accelerated and recently XML security studies are activated using XML which is next generation web standard document format. And XML electronic signature raise interworking between digital signature systems used by various field of using XML document. Using these merit and complementing defect are main contents that users have to pay about Certification service to get CA certificate from 2004 june. This paper propose multiplex Certification remote education agent system using XML digital signature to satisfy security requirement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5B
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• pp.247-252
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• 2005

The testing tools implemented up to now for the LDAP(Light-weight Directory Access Protocol) interoperability tests are not easy to modify or add new test items since their source codes are not open. The object-oriented approach, therefore, is required to implement such a testing tool which can be easily modified or add new test items. Thus we designed the architecture for the testing tool applying the object-oriented approach. Java language, appropriate for the object-oriented approach, was used to implement the testing tool. The newly implemented testing tool can modify partly to adapt to the already stored data in the test suite information even during tests. Five LDAP servers can be tested simultaneously with the same configuration setup. Actual testing for the two LDAP servers validates the usefulness of the designed architecture with the proper working of the implemented testing tool according to the architecture.

• Convergence Security Journal
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• v.8 no.1
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• pp.101-108
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• 2008

This research focuses on the process improvement of port logistics by using Lean methodology. On the one hand, we firstly analyze the current situation and weakness of the processes in port logistics, and then re-design the current processes by the principles of Lean discipline. Based on the appropriately changed processes, the improvement scheme of port logistics will be figured out. On the other hand, we construct the port logistics system by implementing the improved processes. The port logistics' processes accomplished in steel company will be further assorted and identified. The relationship of wharves process, operational process, shipping process, construction process, quality process, and purchasing process are also defined. Every process has been improved by Lean Tools in order to analyze the value added or non-value added processes, to improve the service level, and to reduce the cycle time, inventory, changing time, re-working and waste. Based on above, the appropriate environment that is suitable to Lean process of port logistics will be established and the modeling that can help to implement the improvement scheme will be figured out.

• BMB Reports
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• v.45 no.1
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• pp.44-46
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• 2012

Recent advances in high-throughput genotyping technologies have enabled us to conduct a genome-wide association study (GWAS) on a large cohort. However, analyzing millions of single nucleotide polymorphisms (SNPs) is still a difficult task for researchers conducting a GWAS. Several difficulties such as compatibilities and dependencies are often encountered by researchers using analytical tools, during the installation of software. This is a huge obstacle to any research institute without computing facilities and specialists. Therefore, a proper research environment is an urgent need for researchers working on GWAS. We developed BioSMACK to provide a research environment for GWAS that requires no configuration and is easy to use. BioSMACK is based on the Ubuntu Live CD that offers a complete Linux-based operating system environment without installation. Moreover, we provide users with a GWAS manual consisting of a series of guidelines for GWAS and useful examples. BioSMACK is freely available at http://ksnp.cdc.go.kr/biosmack.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.1
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• pp.51-58
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• 2005

The development of the high-efficiency machine-tools equipment and new cutting tool materials with high hardness, heat- and wear-resistance has opened the way to application of high-speed cutting process. The basic argument of using of high-speed cutting processes is the reduction of time and the respective increase of machining productivity. In this sense, the spindle units may be regarded as one of the most important units, directly affecting many parameters of high-speed machining efficiency. One of the possible types of spindle units for high-speed cutting is the air-bearing type. In this paper, we propose the mathematical model of the dynamic behavior of the air-bearing spindle. To provide the high-level of speed capacity and spindle rotation accuracy we need the adequate model of "spindle-bearings" system. This model should consider characteristics of the interactions between system components and environment. To find the working characteristics of spindle unit we should derive the equations of spindle axis movement under the affecting factors, and solve these equations together with equations which describe the behavior of lubricant layer in bearing (bearing stiffness equations). In this paper, the three influence coefficients are introduced, which describe the center of spindle mass displacement, angle of shaft rotation around the axes under the unit force application and that under the unit torque application. These coefficients are operated in the system of differential equations, which describes the spindle axis spatial movement. This system is solved by Runge-Kutta method. Obtained trajectories and amplitude-frequency characteristics were then compared to experimental ones. The analysis shows good agreement between theoretical and experimental results, which confirms that the proposed model of air-bearing spindle is correctis correct

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.307-315
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• 2020

In this study, we investigate child-care teachers' perceptions of emerging technologies, with a particular focus on fields connected to the Fourth Industrial Revolution. More specifically, we explore how satisfied child-care teachers are with existing educational tools, whether they are interested in or willing to use the latest technology within child care, and their perceived likelihood of adopting these new technologies within child care sites. A total of 181 directors and teachers working at child care institutions in Seoul and Gyeonggi Province participated in the survey. The findings are as follows: firstly, child-care teachers were moderately satisfied with current teaching methods and their effects; secondly, child-care teachers were not especially interested in emerging technologies; thirdly, although interest in applying the latest technology to child care sites was moderately high, refusal to use this technology was also somewhat high; fourthly, many agreed that this technology would eventually become common. This study is expected to provide useful information to those planning to introduce the latest technology to child care sites and basic data to improve teacher training.

• Journal of Digital Contents Society
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• v.13 no.3
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• pp.459-467
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• 2012

In this work, we develop an instructional method in which students create 3D animations based on problem-solving techniques and computational thinking. The educational, easy-to-learn programming environment/language called "Alice 2.3", which supports story-telling, is used for the delivery of the instructional method. Unlike typical 3D animation instructional methods using command-based demonstrations and/or 3D animation tools, learners engage in a group project in which they develop a story and solve problems by creativity, computational thinking and reasoning skills. Then they develop animations based on the story by programming with Alice. The analysis based on the collected data showed that learners had to put much effort while working on the project, but their critical-thinking skills were improved. It also showed they were more involved and their interests were heightened in developing animation through programming.

• Design & Manufacturing
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• v.14 no.1
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• pp.42-48
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• 2020

Titanium alloy has been in the spotlight as a core material in high-tech industries that require high strength and light weight because it has excellent strength and corrosion resistance and strength is higher than that of steel. Therefore, in various industries, existing steel products are intended to be replaced with titanium alloys. Titanium alloys can cause cutting tool breakage during cutting, and heat generated during cutting does not dissipate, accumulates in tools and workpieces, resulting in large wear and tear on thin workpieces. In addition, since titanium alloy is a metal with high chemical activity, the wear of the tool becomes more severe when the cutting speed is high, so machining of titanium bolt through cutting is very disadvantageous in terms of productivity. Therefore, the production of bolts using titanium alloys is being produced through a forging process to improve productivity and product quality. In this paper, hot forging molding analysis was performed on bolts used for fastening automobile parts using Ti-6Al-4V alloy, which is the most commonly used titanium alloy.

• Journal of agricultural medicine and community health
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• v.18 no.2
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• pp.121-129
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• 1993

This study was conducted to investigate the incidence and related factors of farming tool-machinery injuries developed in the Chonnam rural area in 1992. A total of 9,068 persons (4,571men and 4,497women)were selected in a stratified cluster sampling manner, and interviewed individually to complete a structured questionnaire covering farmer characteristics, duration of farm working, annual income, kind of farming tools and machinery, type of injuries and medical care. The results were as follows : 1. The incidence rate of farming tool-machinery injuries was 63 per 1,000 persons over all, 73 in males and 54 in females. The age standardized incidence rate was 69 per 1,000 persons over all, 83 in males and 65 in females. 2. The associated factors with farming tool-machinery injuries in univariate analysis were sex, age, duration of farming and monthly income. The occurrence of injuries was higher in men than in woman, and the higher in high-income group than in the low-income group. 3. More men than woman were involved in trunk injuries and treated at the large scale medical care units such as hospitals, and they paid much higher medical fees. 4. The complaint rates for each item of farmers' syndrome in the injured group were higher than those of the non injured group in 'shoulder stiffness', 'sleeplessness', 'dizziness', and 'gastric fullness'. 5. When multiple logistic regression was applied to farming tool-machinery injuries, the significant variables were farmer's syndrome, age, and duration of farming in both males and females.