• Advances in concrete construction
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• v.10 no.5
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• pp.403-416
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• 2020

This study investigated the effect of alkaline activators - NaOH_aq (NH) (NH: 0-16 M) and Na₂SiO_3aq (NS) (NS/NH: 0-3.5) in the synthesis of silico-manganese fume (SMF) and ground blast furnace slag (BFS) blended alkali-activated mortar (AASB). The use of individual activator was ineffective in producing AASB of sufficient fresh and hardened properties, compared to the synergy of both activators. This may be attributed to incomplete dissolution and condensation of oligomers required for gelation of the binder. An inverse relationship was noted among the fresh properties and the NH concentration or NS/NH ratio. This was influenced by the dissolution and condensation of silicate monomers under polymerization process. The maximum 28-day strength of ~45 MPa, setting time of 60 min and flow of 182 mm was obtained with the use of combined activators (10M-NH and NS/NH=2.5). The combined activators at NS/10M-NH=2.5 constituted SiO₂/Na₂O, H₂O/Na₂O and H₂O/SiO₂ molar ratio of 1.61, 17.33 and 10.77, respectively. This facilitated the formation of C-S-H, C/K-A-S-H and C-Mn-S-H in the framework together with an increase in the crystallinity due to more silicate re-organization within the aluminosilicate chain. On comparison of the high concentrated with mild alkali synthesized product, it revealed that the concentration of OH^- and Si monomers together with alkali metals influenced the dissolution of precursors and embedment of the constituent elements in the polymeric matrix. These factors eventually contributed to the microstructural densification of the mortar prepared with NS/10M-NH=2.5 thereby enhancing the compressive strength.

• Journal of the Korea Society of Computer and Information
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• v.17 no.5
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• pp.1-7
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• 2012

In this paper, we design and implement the simulator for WAN storage replication model performance evaluation in cloud computing environment. Each cloud of simulator is composed of virtual machine emulator and storage emulator. The virtual machine emulator is composed of read/write ratio module, the read/write sequence combination module, and the read/write request module. The storage emulator is composed of storage management module, data transfer module, read/write operations module, and overhead processing module. Using the simulator, we evaluate performance of migration scheme, pre-copy and the post-copy, considering about read/write ratio, network delay, and network bandwidth. Through simulation, we have confirmed that the average migration time of pre-copy was decreased proportional to the read operation. However, average migration time of post-copy was on the increase. Also, the average migration time of post-copy was increased proportional to the network delay. However, average migration time of pre-copy was shown uniformly. Therefore, we show that pre-copy model more effective to reduce the average migration time than the post-copy model. The average migration time of pre-copy and post-copy were not affected by the change of network bandwidth. Therefore, these results show that selects the storage replication model to be, the network bandwidth know not being the important element.

• Journal of Engineering Education Research
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• v.20 no.5
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• pp.59-73
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• 2017

This study aims to examine whether a gender works to make the difference on the university experiences of natural sciences and engineering major students; and the income and quality gap between the graduates. In this study, university experiences means job market and job searching related experiences such as job fair attending, The main research questions are as follows; fist, what are the significant university experiences related job preparation and application, and is there a gender gap on those experiences? Second, how is the job market performance of the national sciences and engineering graduates for their income level and quality job, and is there a gender gap on the job market performance of the sample? Third, which variables among the university experiences for job searching and application impacts the job quality and income level of the natural sciences and engineering graduates? To find out the research results, this study conducts a panel data analysis with GOMS (Graduates Occupational Mobility Survey) throughout survey year of 2006 to 2015, towards 568,264 as weighted value number. As analysis methods, this study carries out a descriptive analysis, ANOVA, discriminant analysis, linear regression and T-test. Therefore, here are the brief outputs of the study; first, for natural sciences and engineering students, the off-campus experiences such as job fair, job recruit festival and internship programs are more favored; second, female students are more likely to attend personal and self-driven job preparation programs; third, on job market performance, the graduates' income level and company scale rate are higher in the male but job stability is higher in the female; fourth, as a result of the linear regression, gender factor decides the income level in considerable degree; additionally, gender factor shows the difference of the job satisfaction and self-effectiveness on one's job as a qualitative variables. For obtaining strictness, university program factors are controlled through model fitness process. As above, this study finds out the main factors of university life of natural sciences and engineering graduates which are related their job searching and preparation experiences and figures out stronger factors in job market; and examines the statistically significance of the gender in this casual-effect relationship between job preparation and job quality of the graduates.

• Journal of the Economic Geographical Society of Korea
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• v.22 no.4
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• pp.422-437
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• 2019

Compared to the significant number of researches on international immigration, there has been less attention to return migration. This is partly because return migration has been understood as a simple phenomenon resulted from a successful return with accumulated capital or adaptation failure. Since the mid-1990s, a large number of Korean-Chinese have migrated to Korea, and recently it became more common to witness the return of them. This study examines the strategic choice of self-employed Korean-Chinese returning to Yanbian, Recently, an increasing number of Korean-Chinese starts a small business, such as restaurants in Yanbian after accumulating capital in Korea. The relatively short stay in Korea is not only for saving money to initiate their own business. Rather, they could obtain new business opportunities in Yanbian by using the experiences and networks built in Korea. In short, the return migration of the Korean-Chinese to Yanbian can be understood as a strategy of capital accumulation utilizing the gap in the World-systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.363-372
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• 2017

This study was conducted to investigate the effects of nursing professional attitude and employment strategy on graduate nursing students core fundamental nursing education program, after applied the core fundamental nursing education program for one semester. There were 165 subjects who were surveyed from June 23 to 24, 2016. The mean score of the core fundamental nursing education program satisfaction was $3.99({\pm}0.48)$. The mean score of nursing professional attitude was $3.77({\pm}0.49)$ and that of employment strategy was $3.28({\pm}0.49)$. The nursing professional attitude related to campus life satisfaction n(p=0.004), employment preparation(p=0.002), factors affecting employment(p=0.005), and employment strategy related with motivation for entering(p=0.018), average credits(p<0.001), employment preparation(p<0.001), information route of employment(p=0.048) showed statistical significance. A significant and positive correlation was found between nursing professional attitude and employment strategy(r=0.472, p<0.001). Nursing professional attitude(${\beta}=0.462$, p<0.001) was found to be an influential variable in core fundamental nursing education programs. The regression model explained 29% of the core fundamental nursing education program(F=17.79, p<0.001). In conclusion, nursing students' nursing professional attitude was related to employment strategy. To increase the core fundamental nursing skills, it is necessary to develop a practical education program and institutional strategies to establish a nursing professional attitude and strengthen employment strategy.

• Journal of Korean Society of Forest Science
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• v.84 no.1
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• pp.77-86
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• 1995

To effectively modify tree function with genetic engineering, transgenes must be expressed at the proper level in the appropriate tissues at suitable developmental stages. Toward understanding the spatial and temporal expression of transgenes in woody plants, transgene expression was evaluated in three greenhouse-grown, transgenic lines of Populus alba ${\times}$ P. grandidentata hybrid clone 'Hansen'. All transgenic poplar lines possess constructs containing the bacterial nopaline synthase(nos) promoter linked to a neomycin phosphotransferase II(NPT II) selectable marker gene. In addition, each transgenic poplar line contains one of the following gene constructs : 1) a wound-inducible potato proteinase inhibitor II (pin2) promoter linked to a chloramphenicol acetyltransferase(CAT) reporter gene. 2) a nos promoter linked to a PIN2 structural gene : or 3) a Cauliflower Mosaic Virus 35s promoter linked to a PIN2 structural gene. Polymerase chain reaction(PCR) was used to verify the presence of foreign genes in the poplar genome. Enzyme-linked immunosorbent assays(ELISAs) were used to evaluate organ specific expression of the nos-NPT II construct. NPT II expression was detected in leaves, petioles, stems, and roots of transgenic poplar, thereby indicating that the nos promoter is potentially effective for general constitutive expression of transgenes. NPT expression varied among transgenic poplar lines and among organs for one transgenic line, Tr15. With Tr15, NPT II levels were highest in older leaves and petioles. These results indicate that screening of several transgenic lines may be required to identify lines with optimal transgene expression.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.8-16
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• 2016

This study presents the visualization of shape information based on Octree using 3D laser scanning. The process of visualization was established to construct the Octree structure from the 3D scan data. The scan data was converted to a 2D surface through the mesh technique and the surface was then converted to a 3D object through the Raster/Vector transformation. The 3D object was transmitted to the Octree Root Node and The shape information was constructed by the recursive partitioning of the Octree Root Node. The test-bed was selected as the steel bridge structure in Sungkyunkwan University. The shape information based on Octree was condensed into 89.3%. In addition, the Octree compressibility was confirmed to compare the shape information of the office building, a computer science campus in Germany and a New College in USA. The basis is created by the visualization of shape information for double-deck tunnel and it will be expected to improve the efficiency of structural health monitoring and maintenance.

• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.343-347
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• 2017

The analytical method of silicon dioxide ($SiO_2$) in health functional food products was developed employing inductively coupled plasma optical emission spectrometry (ICP-OES) method assisted by acid (hydrofluoric acid and boric acid) digestion in open system without alkali fusion. The limit of detection (LOD) and limit of quantification (LOQ) of this method were found to be 0.07 and 0.20 mg/L, respectively. Linearity ($r^2$) and linear range were 0.99 and 0.20~20.0 mg/L, respectively. The accuracy and precision of $SiO_2$ (0.4, 1.0, and 2.0%, w/w) in spiked glucosamine exhibited to be the range of 90.22~94.14% and 0.72~1.67%, respectively. The contents of $SiO_2$ in 11 health functional food products were detected in range of 0.02~1.80% (w/w). Every sample showed below content of the permitted use level (2%, w/w) of $SiO_2$. Therefore ICP-OES method with acid can analyze the content of $SiO_2$ in health functional food products easily and rapidly. Consequently, the application of specification analysis of $SiO_2$ in health functional food products could be a significant work.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.7
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• pp.1042-1047
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• 2014

This study examined the quality characteristics of Yanggaeng added with tomato powder (0, 5, 10, 15, and 20%) and oligosaccharides instead of red beans and sugar. The moisture content of tomato Yanggaeng was 45.89~33.64% and was highest in the control group. The pH ranged 3.96~6.24 and significant decreased with the addition of tomato powder. Hunter's color value, lightness (L value) were the highest in Yanggaeng added with 20% tomato powder. Redness (a value) increased with tomato powder content, except for 20% tomato powder. Yellowness (b value) significantly increased with tomato powder content (P<0.05) but decreased with 20% tomato powder. In the texture profile analysis, hardness, cohesiveness, gumminess, and chewiness significantly decreased (P<0.05) with the addition of tomato powder. Total soluble solid content ($^{\circ}Brix$) was the highest (5.16) in the control group, whereas that of tomato Yanggaeng ranged 4.46~4.92 and significantly decreased (P<0.05) with the addition of tomato powder. The antioxidative activity based on 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of Yanggaeng increased with the concentration of tomato powder, although those of Yanggaeng added with 15% and 20% tomato powder were not significantly different (P<0.05). Yanggaeng added with 5 and 10% tomato powder showed acceptable sensory properties, including color, flavor, sweet taste, sour taste, and overall quality. In terms of sensory evaluation and antioxidant activity, the results show that Yanggaeng added with 10% tomato powder was the best, but more research should be conducted in order to improve sensory acceptability.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.756-761
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• 2016

The objective of this study is to design and manufacture a fuel pump with the plunger diameter of 4 mm and stroke of 7 mm that can be mounted in a small single-cylinder four-stroke agricultural diesel engine, and to investigate the performance characteristics of the pump. The combustion pressure in a cylinder was reproduced by forming the back pressure of 1, 6, 11, 16 and 21 bar with a nitrogen gas in the home-manufactured modeling cylinder. In the experiment, the discharge pressure was measured at the spot of 1 cm away from the discharge port of a developed fuel pump. The delivery pressure and delivery flow rate were measured at the spot of 30 cm away from the discharge port of the pump, and the pump efficiency was calculated. The pump motor speed was changed from 600 to 800, 1000, 1200 and 1400 rpm. It is found that the delivery feed rate of fuel pump is increased as the rotational speed is raised, and is decreased as the back pressure, compression pressure in the cylinder, is increased. Also, the pump efficiency is reduced as the rotational speed and back pressure are increased.