• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.6
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• pp.128-133
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• 2011

In this study, the steel material for shipbuilding(LR-A class) was used, and FCAW was taken advantage of 3G attitude and they are welded by different welding ways. As a result of analyzing wave with welding monitoring system, the stable values are obtained which are the first floor(electronic current 164~182 A, voltage 24 V), the second floor(electronic current 174~190 A, voltage 22~25 V), the third floor(electronic current 158~188 A, voltage 22~25 V), and fourth floor(electronic current 172~184 A, voltage 22~25 V), at this time, the stable wave standard deviation and changing coefficient could be obtained. When the welding testing through nondestructive inspection was analyzed know defect of welding, there was no defect of welding in A, D, E, but some porosities in B, and slag conclusion near the surface in C, because the length of arc was not accurate, and the electronic current and voltage was not stable. After observing the change of heat affect zone through micro testing, each organization of floor formed as Grain Refinement, so welding part was fine, the distance of heat affect zone is getting wider up to change the values of the electronic current and voltage. As a result of degree of hardness testing, the hardness orders were the heat affect zone(HAZ), Welding Zone(WZ), and Base Metal(BM). When the distribution of degree of hardness is observed. B is the highest degree of hardness The reason why heat effect zone is higher than welding zone and base metal, welding zone is boiled over melting point($1539^{\circ}C$) and it starts to melt after the result of analysis through metal microscope, so we can know that delicate tissue is created at the welding zone. Therefore, in order to get the optimal conditions of the welding, the proper current of the welding and voltage is needed. Furthermore the precise work of welding is required.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.1951-1957
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• 2007

A new synthetic strategy based on the acid-base catalyzed sol-gel method was developed for the preparation of a series of mesoporous TiO2 nanoparticles. A key feature of the method involves a gradual change in pH (0.8- 9) during the sol-gel transition, which guarantees easy introduction of mesoporosity without relying on the well-established sonochemical or template approach. In addition, this method leads to the exclusive formation of the anatase phase stable enough to the calcination temperature up to 600 oC. The physicochemical properties of the particles in the series were characterized by various spectroscopic and analytical techniques such as wide-angle XRD, SAXRD, BET surface area, FE-SEM, TEM, FT-IR, TGA, and XPS. The photocatalytic efficiency of these materials was investigated for the oxidation of toluene under UV-irradiation. All but T-ad in the series exhibited high photocatalytic activity pushing the reaction into completion within 3 h. The reaction followed the first order kinetics, and the rate reaches as high as 3.9 × 10?2/min which exceeds the one with the commercially available Degussa P-25 by a factor of 3.2. When comparison is made among the catalysts, the reactivity increases with increase in the calcination temperature which in turn increases the crystallinity of the anatase phase, thus revealing the following rate orders: T-3 < T-4 < T-5 < T-6.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.4
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• pp.53-62
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• 2009

Lee[15] examined quantity discount contracts between a manufacturer and a retailer in a stochastic, two-period inventory model where quantity discounts are provided based on the previous order size. During the two periods, the retailer faces stochastic (truncated Poisson distributed) demands and he/she places orders to meet the demands. The manufacturer provides for the retailer a price discount for the second period order if its quantity exceeds the first period order quantity. In this paper we extend the above two-period model to a k-period one (where k < 2) and propose a stochastic nonlinear mixed binary integer program for it. In order to make the program tractable, the nonlinear term involving the sum of truncated Poisson cumulative probability function values over a certain range of demand is approximated by an i-interval piecewise linear function. With the value of i selected and fixed, the piecewise linear function is determined using an evolutionary algorithm where its fitness to the original nonlinear term is maximized. The resulting piecewise linear mixed binary integer program is then transformed to a mixed binary integer linear program. With the k-period model developed, we suggest a solution procedure of receding horizon control style to solve n-period (n < k) order decision problems. We implement Lee's two-period model and the proposed k-period model for the use in receding horizon control style to solve n-period order decision problems, and compare between the two models in terms of the pattern of order quantities and the total profits. Our computational study shows that the proposed model is superior to the two-period model with respect to the total profits, and that order quantities from the proposed model have higher fluctuations over periods.

• Journal of the Korean Home Economics Association
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• v.29 no.4
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• pp.115-130
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• 1991

The purpose of this study is to examine the variables which influence old widows' life satisfaction. The subjects were 318 old widows over sixty years old in Kwangju. The data were taken by questionaires and analyzed by frequency distribution, percentile, AHOVA, scheffes test and multiple regression. The major findings of this study were as follows: 1) The majority of old widows were low educated and 36.2% were poor in health. Their living aspect that they live together with their married child was 74.2%. Degree of participation in social activities was very low. 42% were satisfied or very satisfied with their pocket money. 76.4% had religions. 25.5% had no old friend. Solidarity with their children was generally good. In their economical status, 8.4% of living together with married children were low while 35.3% of living separately were. 60% thought that they were important person at home. 35.5% answered that they were satisfied with their living condition and 6% were very satisfied. 2) The variables which affect the old widows' life satisfaction were age(p<0.05), state of health(p<0.001), degree of pocket money(p<0.01), economical status(p<0.05), roles at home(p<0.01), solidarity among their relatives(p<0.001), solidarity with their children(p<0.001), status in home(p<0.001) participation in social activities(p<0.05) and existence of old friend(p<0.01). 3) The significant orders which affect the old widow's life satisfaction were satus in home first of all (β=0.26, p<0.001), objective solidarity with their children(β=0.21, p<0.001), subjuctive solidarity with their children(β=0.19, p<0.01), state of health (β=0.15, p<0.01) and economical status who living with married child (β=0.15, p<0.01).

• The KIPS Transactions:PartD
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• v.13D no.3 s.106
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• pp.357-368
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• 2006

This paper discusses the way of processing time-series subsequence matching under time warping. Time warping enables finding sequences with similar patterns even when they are of different lengths. The prefix-querying method is the first index-based approach that performs time-series subsequence matching under time warping without false dismissals. This method employs the $L_{\infty}$ as a base distance function for allowing users to issue queries conveniently. In this paper, we extend the prefix-querying method for absorbing $L_1$, which is the most-widely used as a base distance function in time-series subsequence matching under time warping, instead of $L_{\infty}$. We also formally prove that the proposed method does not incur any false dismissals in the subsequence matching. To show the superiority of our method, we conduct performance evaluation via a variety of experiments. The results reveal that our method achieves significant performance improvement in orders of magnitude compared with previous methods.

• Korean Institute of Interior Design Journal
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• v.21 no.5
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• pp.244-253
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• 2012

Vincent van Gogh is a Dutch postimpressionism artist that is one of the most influential painter of the 20th century with his vivid colors and sensibility. 'The Bedroom at Arles' is the art piece that van Gogh himself had admitted to be a great artwork, which also reflects the story of his life and inner thoughts. The spacial characteristics of 'The Bedroom at Arles' are amanufactures the following. First, the space shown at 'The Bedroom at Arles' exhibits the phenomenon of undoing the law of perspective by authorizing individual existence to the objects and space, instead of fitting in the objects into the space in the order given by the law of perspective; entirely rearranging the reminiscent space from past. Secondly, the expression 'bedroom' reflects that the subject was about his own experience with the space and a representation of his imagination, which is a metaphorical symbol. Thirdly, van Gogh used strong colors and brush touches to express his subjective opinion, which aren't the actual shades of the scene, but chosen only to approach the space and objectives with his own symbolic interpretation from his heart. Through a synthetic overview of the characteristics of van Gogh's 'The Bedroom at Arles', it could be told that he holds an essential Space perception system, in hir inner self. The space is intentionally rearranged and strangely altered to form an entirely new relation, breaking the tension from the systematically stable rules and orders. 'The Bedroom at Arles' seems to express an unique and symbolic sensation and experience through the combination of its colors and spacial structure.

• Journal of the Korean Society for Library and Information Science
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• v.34 no.3
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• pp.109-132
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• 2000

With purpose of improving library technology, one of the core elements of library automation technology, are suggested. The results of the study revealed article database standards briefly described as follows: First, database concerning articles in serials are generated from previous indices & abstracts journals. Second, bibliographic elements of ten representative domestic and international bibliographic database systems showed many dissimilar descriptive field types, as well as differences in entry orders and details. Third, database standards or guidelines were non-existent in domestic and international bibliographic database agencies, and different format have been adapted among those agencies. It is strongly recommended that all library should create a plan for adapting internationally standards in data input format as well as output format. Fourth, conforming with ISO 690 bibliographic descriptions, their ten components will be adapted as the basic framework for building the database and appropriately select additional seven data components of total 17 categories.

• Journal of Ocean Engineering and Technology
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• v.27 no.5
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• pp.105-114
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• 2013

Lots of orders of special vessels and offshore plants for developing the resources in deepwater have been increased in recent. Because the most of accidents on those structures are caused by fire and explosion, many researchers have been investigated quantitatively to predict the cause and effect of fire and explosion based on both experiments and numerical simulations. The first step of the evaluation procedures leading to fire and explosion is to predict the dispersion of flammable or toxic material, in which the released material mixes with surrounding air and be diluted. In particular turbulent mixing, but density differences due to molecular weight or temperature as well as diffusion will contribute to the mixing. In the present paper, the numerical simulation of hydrogen dispersion inside a simple-shaped offshore structure was performed using a commercial CFD program, ANSYS-CFX. The simulated results for concentration of released hydrogen are compared to those of experiment and other simulation in Jordan et al.(2007). As a result, it is seen that the present simulation results are closer to the experiments than other simulation ones. Also it seems that the hydrogen dispersion is closely related to turbulent mixing and the selection of the turbulence model properly is significantly of importance to the reproduction of dispersion phenomena.

• Journal of the Korea Society of Computer and Information
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• v.26 no.11
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• pp.75-84
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• 2021

In this paper, we propose an adaptive concurrency control scheme to reduce conflicts and working time in the cooperative work in mixed reality. To this ends, we first classified the goals, tasks and ownerships of the cooperative work. Then, the classified relationships are mapped according to their temporal and hierarchical relationships of shared object manipulation in the cooperative work. The proposed system provides adaptive concurrency controls of the shared object according to temporal orders of the sub-goals. With the proposed scheme, a participant is enable to move and rotate a shared object although another already has an ownership of the shared object in a specific order of the sub-goal. Thus, the proposed system provides adaptive and realistic cooperative working environment. We conducted a user study of the proposed scheme. The proposed system could reduce conflicts and working times comparing to conventional approaches.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.4
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• pp.907-918
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• 2019

The purpose of this study is to understand the cybersecurity policies and critical infrastructure protection of the United States through analyzing Donald Trump's administration executive orders, the national cyber strategy, and the legislation. The analysis has three findings. First, the Department of Homeland Security (DHS) became a main agent in the cybersecurity while the role of the White House was reduced. Second, Trump's administration expanded its role and mission in the policy area by extending the meaning of critical infrastructure. Third, in the case of cyber threats, the government can be involved in the operation of critical infrastructures in the private sector. The opinions of the professional bureaucrats and DHS were more reflected in the direction of the cybersecurity policy than those of the White House. In contrast to Barack Obama's administration, the Trump administration's cybersecurity strategies were not much studied. This study provides insights for improving cybersecurity policies and critical infrastructure protection.