• Journal of Welding and Joining
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• v.35 no.2
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• pp.43-51
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• 2017

The automatic welding systems, have received much attention in recent years, because they are highly suitable not only to increase the quality and productivity, but also to decrease manufacturing time and cost for a given product. Automatic welding work in semiconductor or space industry to be carried out in pipe line and butt joint mostly and plasma arc welding(PAW) is actively applied. To get the desired quality welds in automated welding system is challenging, a mathematical model is needed that has complete control over the relevant process parameters in order to obtain the required mechanical properties. However, In various industries the welding process mathematical model is not fully formulated for the process parameter and on the welding conditions, therefore only partial variables can be predicted. Therefore, this paper investigates the interaction between the welding parameters and mechanical properties for predicting the weld bead geometry by analyzing the S/N ratio.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.630-630
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• 2013

Recently, atomically smooth hexagonal boron nitride(h-BN) known as a white graphene has drawn great attention since the discovery of graphene. h-BN is a III-V compound and has a honeycomb structure very similar to graphene with smaller lattice mismatch. Because of strong covalent sp2bonds like graphene, h-BN provides a high thermal conductivity and mechanical strength as well as chemical stability of h-BN superior to graphene. While graphene has a high electrical conductivity, h-BN has a highly dielectric property as an insulator with optical band gap up to 6eV. Similar to the graphene, h-BN can be applied to a variety of field, such as gate dielectric layers/substrate, ultraviolet emitter, transparent membrane, and protective coatings. However, up until recently, obtaining and controlling good quality monolayer h-BN layers have been too difficult and challenging. In this work, we investigate the controlled synthesis of h-BN layers according to the growth condition, time, temperature, and gas partial pressure. h-BN is obtained by using chemical vapor deposition on Cu foil with ammonia borane (BH3NH3) as a source for h-BN. Scanning Transmission Electron Microscopy (STEM, JEOL-JEM-ARM200F) is used for imaging and structural analysis of h-BN layer. Sample's surface morphology is characterized by Field emission scanning electron microscopy (SEM, JEOL JSM-7100F). h-BN is analyzed by Raman spectroscopy (HORIBA, ARAMIS) and its topographic variations by Atomic force microscopy (AFM, Park Systems XE-100).

• Korean Journal of Childcare and Education
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• v.9 no.5
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• pp.181-200
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• 2013

This study aimed at exploring how an instructor constructs meanings through content-based instruction (CBI) offered to pre-service teachers majoring in early childhood education. The course, early childhood mathematics education, was conducted during the spring semester in 2011. This study adopted a narrative inquiry, and data were collected through observations, interviews, and work samples. This study found that during the whole process from the preparation phase to the end-of-program evaluation, the instructor captured diverse challenging moments. During the preparation phase, she needed to have careful orchestration in designing lessons in order to overcome her feeling of pressure as a non-native speaker of English and design the integration of contents and English language learning to be truly powerful. In the phase of implementation, the lack of student motivation and building a good rapport between the instructor and the students were certainly challenges. The result of the student evaluations weakened her desire to implement CBI. The instructor incorporated diverse instructional strategies to overcome the obstacles. The instructor's experiences in this study will positively shape future educators' thinking and learning about meaningful and appropriate academic English instruction for content-area teaching of college students who were majoring in early childhood education.

• The Research Journal of the Costume Culture
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• v.23 no.2
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• pp.193-212
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• 2015

The purpose of this study is to analyze the characters and images of Picasso's muses, to extract the color chip from the works of Picasso, and to apply these results to fashion design. The study includes a literature review, an analysis of visual materials. The results are as follows. Fernande, who was cheerful and voluptuous, was depicted with pink-brown, a few browns, grey, black, white, and green and represents an ethnic and elegant image. Eva, a star-crossed lover, was depicted with a few browns, black, and pale-yellow and represents a gorgeous and natural image. Olga, who was jealous and sickly wife, was depicted with a few blues, browns and neutral-color and represents a classic and dandy image. Th${\acute{e}}$r${\grave{e}}$se, who was innocent and sweet, was depicted with the bright and pastel colors of red, green, violet, and yellow and of white, blue, brown, and black and represents a romantic, pretty, and casual image. Dora, who was intellectually and emotionally- challenging, was depicted with the strong colors of red, yellow, green, and blue, which are in contrast to black and also to white, grey and brown and represents a wild and dynamic image. Gilot, who was strong-willed and prideful, was depicted with the symbolic color of green, a color contrasting with black and white, grey, and pale brown and represents a clear, cool casual and modern image. Jacqueline, the self-giving and reclusive wife, was depicted with deep red, blue, green, black, white, dark brown, grey represents a formal, dandy, and chic image.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1009-1012
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• 2008

The fiber dispersion performance in fiber-reinforced cementitious composites is a crucial factor with respect to achieving desired mechanical performance. However, evaluation of the fiber dispersion performance in the composite PVA-ECC(Polyvinyl alcohol-Engineered Cementitious Composite) is extremely challenging because of the low contrast of PVA fibers with the cement-based matrix. In the present work, an enhanced fiber detection technique is developed and demonstrated. Using a fluorescence technique on the PVA-ECC, PVA fibers are observed as green dots in the cross-section of the composite. After capturing the fluorescence image with a Charged Couple Device(CCD) camera through a microscope. The fibers are more accurately detected by employing a series of process based on a categorization, watershed segmentation, and morphological reconstruction.

• 한국사회복지학회:학술대회논문집
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• 2004.06a
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• pp.3-50
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• 2004

${\cdot}$ Recent social policy and labour markets debates in Europe, responding to the difficulties faced by the traditional neo-Keynesian welfare state settlement, stress the value of positive investment alongside de-regulation and greater flexibility as a way of achieving both economic and social goals. ${\cdot}$ Patterns of policy reform are complex and reflect differing national circumstances. A general move towards deregulation, constraints on entitlement to passive benefits, programmes to enhance employment, particularly among high-risk groups such as single parents and young people, targeted subsidies for low earners and casemanagement may be identified. ${\cdot}$ In relation to investment in education, research and development and combined training and benefit programmes to enhance mobility between jobs the picture is less clear. Education standards continue to rise, but research and development spending stagnates and few countries have developed substantial ‘flexi-curity’ programmes to support job mobility. ${\cdot}$ The labour market tradition in much of Europe has been one of conflict between labour and employers. As labour grows weaker, new approaches develop. These tend to stress productivity agreements and greater flexibility in work practices within firms and reforms to passive social security systems more broadly, but movement to support the more challenging investment and flexi-curity policies is slow. ${\cdot}$ In general, social and labour market policies in Europe stress deregulation and negative activation more strongly than social investment and ‘flexi-curity’. The countries with high growth and employment achieve that goal by different routes: Sweden has a closely integrated social democratic corporatism with high spending on benefits and training programmes and the UK a more liberal market-oriented system, with lower spending, highly targeted benefits and less mobility support. ${\cdot}$ Europe has something to learn from Korea in achieving high investment in human capital and R and D, while Korea may have something to learn from Europe in social investment, particularly flexi-curity and equal opportunity policies.

• Ocean Systems Engineering
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• v.7 no.2
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• pp.143-155
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• 2017

For complex flexible structures such as nets, the determination of drag forces and its deformation is a challenging task. The accurate prediction of loads on cages is one of the key steps in designing fish farm facilities. The basic physics with a simple cage, can be addressed by the use of experimental studies. However, to design more complex cage system for various environmental conditions, a reliable numerical simulation tool is essential. In this work, the current load on a cage is calculated using a Morison-force model applied at instantaneous positions of equivalent-net modeling. Variations of solidity ratio ($S_n$) of the net and current speed are considered. An equivalent array of cylinders is built to represent the physical netting. Based on the systematic comparisons between the published experimental data for Raschel nets and the current numerical simulations, carried out using the commercial software OrcaFlex, a new formulation for $C_d$ values, used in the equivalent-net model, is presented. The similar approach can also be applied to other netting materials following the same procedure. In case of high solidity ratio and current speed, the hybrid model defines $C_d$ as a function of Re (Reynolds number) and $S_n$ to better represent the corresponding weak diffraction effects. Otherwise, the conventional $C_d$ values depending only on Re can be used with including shielding effects for downstream elements. This new methodology significantly improves the agreement between numerical and experimental data.

• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.23-29
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• 2020

Since the movements of a machine are driven by a certain principle, there is a fundamental principle that governs the movement of the machine, no matter how complex and diverse it may be. Autonomous movements are a way to avoid repetition, to approach more humane and more natural factors. That's all the more so when it comes to original movements, not cloning. So now, the dynamics of the machine are more multi-sensory by human participation. It is challenging the potential to be expressed and is gradually expanding its sphere of expression in the boundaries of fact and cloning. Theo Jansen's works have changed from period to period to adapt to different circumstances, indicating that his decades-long work has continued to evolve from early to present. The evolution's focus, among other things, can be seen as having the same source of circular motion and horizontal reciprocating motion, which are repeated from the principle of organic coupling between the parts that make up the object.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1438-1439
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• 2006

$Ge_{2}Sb_{2}Te_5$(GST) thin film at present is a promising candidate for a phase change random access memory (PCRAM) based on the difference in resistivity between the crystalline and amorphous phase. PCRAM is an easy to manufacture, low cost storage technology with a high storage density. Therefore today several major chip in manufacturers are investigating this data storage technique. Recently, A. Pirovano et al. showed that PCRAM can be safely scaled down to the 65 nm technology node. G. T Jeonget al. suggested that physical limit of PRAM scaling will be around 10 nm node. Etching process of GST thin ra films below 100 nm range becomes more challenging. However, not much information is available in this area. In this work, we report on a parametric study of ICP etching of GST thin films in $Cl_2$/Ar chemistry. The etching characteristics of $Ge_{2}Sb_{2}Te_5$ thin films were investigated using an inductively coupled plasma (ICP) of $Cl_2$/Ar gas mixture. The etch rate of the GST films increased with increasing $Cl_2$ flow rate, source and bias powers, and pressure. The selectivity of GST over the $SiO_2$ films was higher than 10:1. X-ray photoelectron spectroscopy(XPS) was performed to examine the chemical species present in the etched surface of GST thin films. XPS results showed that the etch rate-determining element among the Ge, Sb, and Te was Te in the $Cl_2$/Ar plasma.

• Safety and Health at Work
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• v.9 no.1
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• pp.42-52
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• 2018

Background: Maintenance operations on-board ships are highly demanding. Maintenance operations are intensive activities requiring high man-machine interactions in challenging and evolving conditions. The evolving conditions are weather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress. For example, extreme weather condition affects seafarers' performance, increasing the chances of error, and, consequently, can cause injuries or fatalities to personnel. An effective human error probability model is required to better manage maintenance on-board ships. The developed model would assist in developing and maintaining effective risk management protocols. Thus, the objective of this study is to develop a human error probability model considering various internal and external factors affecting seafarers' performance. Methods: The human error probability model is developed using probability theory applied to Bayesian network. The model is tested using the data received through the developed questionnaire survey of >200 experienced seafarers with >5 years of experience. The model developed in this study is used to find out the reliability of human performance on particular maintenance activities. Results: The developed methodology is tested on the maintenance of marine engine's cooling water pump for engine department and anchor windlass for deck department. In the considered case studies, human error probabilities are estimated in various scenarios and the results are compared between the scenarios and the different seafarer categories. The results of the case studies for both departments are also compared. Conclusion: The developed model is effective in assessing human error probabilities. These probabilities would get dynamically updated as and when new information is available on changes in either internal (i.e., training, experience, and fatigue) or external (i.e., environmental and operational conditions such as weather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress) factors.